ACCURATE SPEEDOMETER?
09-17-2007, 11:48 PM
#141
Guest
Posts: n/a
Re: ACCURATE SPEEDOMETER?
Tracie wrote:
> On Sep 17, 10:36 pm, c <c...@me.org> wrote:
>> Tracie wrote:
>>> On Sep 17, 6:49 pm, twaldron <d...@hairsproutingbunions.com> wrote:
>>>> Tracie wrote:
>>>>> On Sep 17, 3:49 pm, "L.W. \(Bill\) ------ III"
>>>>> <LWBillHug...@------.net> wrote:
>>>>>> Doesn't your Rubicon automatically correct for tire size? Probably by
>>>>>> this '06 it also measures the distance from the ground.
>>>>>> God Bless America, Bill O|||||||O
>>>>>> mailto:LW------...@aol.comhttp://www.----------.com/
>>>>>> "twaldron" <d...@hairsproutingbunions.com> wrote in message
>>>>>> news:WcxHi.1705$ec2.502@trnddc03...
>>>>>>> Your minimal tire size increase likely made your speedo/odo more
>>>>>>> accurate as they tend to read high from the manufacturer. That way
>>>>>>> warranties expire sooner and manufacturers save money. I'd bet you are
>>>>>>> very close now. For fuel economy, use the highest gear you can while
>>>>>>> staying in the power band (not lugging). Lugging will become immediately
>>>>>>> apparent and you do it by feel, not by someone telling you what RPM to
>>>>>>> run. If you shift into too high a gear, you will notice a power response
>>>>>>> loss and ultimately your engine will lug. Downshift.
>>>>>>> tw
>>>>>> --
>>>>>> Posted via a free Usenet account fromhttp://www.teranews.com
>>>>> Well, I do have an appt at the dealership tomorrow around 5 pm
>>>>> (eastern time). When I find out whether or not my speedo is right on
>>>>> or off a few mph, I will certainly post the results to let you all
>>>>> know. In the meantime, I really don't have a lugging issue or a power
>>>>> loss with the 3.07s and 31s. I can start up a moderate sized hill
>>>>> doing 65 (according to the speedometer) in 5th gear, and not have to
>>>>> stomp the gas pedal to continue going up the hill at a nice pace. I
>>>>> am wondering if the spec sheet on my jeep is wrong, and I actually
>>>>> have 3.73s. I will look at the rear diff case tonight and see what
>>>>> the stamp says.
>>>> Are you making a special trip to the dealer to check your speedo??
>>>> tw- Hide quoted text -
>>>> - Show quoted text -
>>> Not really. I have had this appt scheduled for a few days now. I am
>>> not really good at some things when it comes to this stuff. However,
>>> I did try the measured mile trick on the way home tonight, and used
>>> the formula that someone posted here earlier (3600/time it takes to go
>>> 1 mile) = actual speed. When my speedometer reads 60, it took me 54
>>> seconds to go 1 mile. Hence I am assuming my actual speed is
>>> approximately 66.5 mph (3600/54=66.6).
>>> As for the 3.73s, no such luck. : ( I am stuck with the 3.07s.
>>> Although as I mentioned earlier, it's really not that bad. At least
>>> not as bad as I had expected. There is a noticeable difference from
>>> the stock sized tires, but I really don't notice it until I get into
>>> 5th gear. Then again, before this 6 speed, I was used to driving a 5
>>> speed anyway. And finally, there's the great debate of whether or not
>>> to use 6th gear and if so, at what speed/rpm.
>>> One thing.....what is engine pinging and what does it sound like? I
>>> have a 'funny' noise that my jeep makes (seems to be coming from the
>>> passenger side) while going uphill. To me, it sounds like keys
>>> jingling very softly and intermittently. It never happened (that I
>>> remember) prior to the installation of the bigger tires. The engine
>>> is not skipping, sputtering, or seem to be lugging at all when this
>>> noise occurs. It usually starts right at the beginning of a moderate
>>> sized hill and continues intermittently until I get to the top of the
>>> hill. And it NEVER happens when the engine is cold (first 30-45
>>> minutes of driving hills or not) or while going downhill. I don't
>>> know if this makes a difference, but I have been using 87 octane fuel
>>> since I bought it new in November of 2006. Just to see if it made a
>>> difference, I filled her up with 89 octane today. Gonna run her a
>>> couple of days and see if I still notice this noise.
>> The "key jingling" sound you hear is probably pinging. That is actually
>> a good way to describe it. I used to always tell people it sounds like
>> light tapping on a piece of metal with a small hammer.
>>
>> Chris- Hide quoted text -
>>
>> - Show quoted text -
>
>
> Any idea why this would happen when I don't seem to be lugging the
> engine? Could it be strictly related to the increased tire size? I
> know how to 'feel' an engine to shift without lugging (been driving a
> stick for the past 13 years) or to shift into a lower gear while going
> uphill if engine seems to be lugging. Other than the 87 fuel I was
> using, I have no clue. Is this harmful if it continues, and is there
> a way to avoid it from happening? I drive approximately 35 minutes
> each way to work, and it only happens 2-3 times each way for about 10
> seconds each time (not a straight 10 seconds, but intermittently 2-3
> times in that 10 seconds).
>
When your tire diameter increased, it effectively increases the load on
the engine. Kind of like adding weight to the vehicle. Yes it is harmful
to the engine if you let it keep happening. What you are actually
hearing is the fuel igniting in the cylinder before it is supposed to.
It is caused from excessive cylinder pressure. Over time it can cause
broken pistons and piston rings, blown head gaskets, and in extreme
cases, a cracked cylinder or head. Higher octane fuel will stop the
pinging, as will keeping the transmission in a lower gear.
What you can do to test the cost effectiveness of the high octane fuel
is to run one tank of 87 octane while using the lower gear and check
your fuel mileage. then do the same with 89 octane and see if you can
run like you did before the tire change. If the fuel mileage offsets the
cost of the higher octane fuel, then that is the best way to go. Some
vehicles will see a good increase in mileage if the fuel allows it to be
run in the higher gear. The only way you can know for sure is to test
your particular vehicle.
Chris
> On Sep 17, 10:36 pm, c <c...@me.org> wrote:
>> Tracie wrote:
>>> On Sep 17, 6:49 pm, twaldron <d...@hairsproutingbunions.com> wrote:
>>>> Tracie wrote:
>>>>> On Sep 17, 3:49 pm, "L.W. \(Bill\) ------ III"
>>>>> <LWBillHug...@------.net> wrote:
>>>>>> Doesn't your Rubicon automatically correct for tire size? Probably by
>>>>>> this '06 it also measures the distance from the ground.
>>>>>> God Bless America, Bill O|||||||O
>>>>>> mailto:LW------...@aol.comhttp://www.----------.com/
>>>>>> "twaldron" <d...@hairsproutingbunions.com> wrote in message
>>>>>> news:WcxHi.1705$ec2.502@trnddc03...
>>>>>>> Your minimal tire size increase likely made your speedo/odo more
>>>>>>> accurate as they tend to read high from the manufacturer. That way
>>>>>>> warranties expire sooner and manufacturers save money. I'd bet you are
>>>>>>> very close now. For fuel economy, use the highest gear you can while
>>>>>>> staying in the power band (not lugging). Lugging will become immediately
>>>>>>> apparent and you do it by feel, not by someone telling you what RPM to
>>>>>>> run. If you shift into too high a gear, you will notice a power response
>>>>>>> loss and ultimately your engine will lug. Downshift.
>>>>>>> tw
>>>>>> --
>>>>>> Posted via a free Usenet account fromhttp://www.teranews.com
>>>>> Well, I do have an appt at the dealership tomorrow around 5 pm
>>>>> (eastern time). When I find out whether or not my speedo is right on
>>>>> or off a few mph, I will certainly post the results to let you all
>>>>> know. In the meantime, I really don't have a lugging issue or a power
>>>>> loss with the 3.07s and 31s. I can start up a moderate sized hill
>>>>> doing 65 (according to the speedometer) in 5th gear, and not have to
>>>>> stomp the gas pedal to continue going up the hill at a nice pace. I
>>>>> am wondering if the spec sheet on my jeep is wrong, and I actually
>>>>> have 3.73s. I will look at the rear diff case tonight and see what
>>>>> the stamp says.
>>>> Are you making a special trip to the dealer to check your speedo??
>>>> tw- Hide quoted text -
>>>> - Show quoted text -
>>> Not really. I have had this appt scheduled for a few days now. I am
>>> not really good at some things when it comes to this stuff. However,
>>> I did try the measured mile trick on the way home tonight, and used
>>> the formula that someone posted here earlier (3600/time it takes to go
>>> 1 mile) = actual speed. When my speedometer reads 60, it took me 54
>>> seconds to go 1 mile. Hence I am assuming my actual speed is
>>> approximately 66.5 mph (3600/54=66.6).
>>> As for the 3.73s, no such luck. : ( I am stuck with the 3.07s.
>>> Although as I mentioned earlier, it's really not that bad. At least
>>> not as bad as I had expected. There is a noticeable difference from
>>> the stock sized tires, but I really don't notice it until I get into
>>> 5th gear. Then again, before this 6 speed, I was used to driving a 5
>>> speed anyway. And finally, there's the great debate of whether or not
>>> to use 6th gear and if so, at what speed/rpm.
>>> One thing.....what is engine pinging and what does it sound like? I
>>> have a 'funny' noise that my jeep makes (seems to be coming from the
>>> passenger side) while going uphill. To me, it sounds like keys
>>> jingling very softly and intermittently. It never happened (that I
>>> remember) prior to the installation of the bigger tires. The engine
>>> is not skipping, sputtering, or seem to be lugging at all when this
>>> noise occurs. It usually starts right at the beginning of a moderate
>>> sized hill and continues intermittently until I get to the top of the
>>> hill. And it NEVER happens when the engine is cold (first 30-45
>>> minutes of driving hills or not) or while going downhill. I don't
>>> know if this makes a difference, but I have been using 87 octane fuel
>>> since I bought it new in November of 2006. Just to see if it made a
>>> difference, I filled her up with 89 octane today. Gonna run her a
>>> couple of days and see if I still notice this noise.
>> The "key jingling" sound you hear is probably pinging. That is actually
>> a good way to describe it. I used to always tell people it sounds like
>> light tapping on a piece of metal with a small hammer.
>>
>> Chris- Hide quoted text -
>>
>> - Show quoted text -
>
>
> Any idea why this would happen when I don't seem to be lugging the
> engine? Could it be strictly related to the increased tire size? I
> know how to 'feel' an engine to shift without lugging (been driving a
> stick for the past 13 years) or to shift into a lower gear while going
> uphill if engine seems to be lugging. Other than the 87 fuel I was
> using, I have no clue. Is this harmful if it continues, and is there
> a way to avoid it from happening? I drive approximately 35 minutes
> each way to work, and it only happens 2-3 times each way for about 10
> seconds each time (not a straight 10 seconds, but intermittently 2-3
> times in that 10 seconds).
>
When your tire diameter increased, it effectively increases the load on
the engine. Kind of like adding weight to the vehicle. Yes it is harmful
to the engine if you let it keep happening. What you are actually
hearing is the fuel igniting in the cylinder before it is supposed to.
It is caused from excessive cylinder pressure. Over time it can cause
broken pistons and piston rings, blown head gaskets, and in extreme
cases, a cracked cylinder or head. Higher octane fuel will stop the
pinging, as will keeping the transmission in a lower gear.
What you can do to test the cost effectiveness of the high octane fuel
is to run one tank of 87 octane while using the lower gear and check
your fuel mileage. then do the same with 89 octane and see if you can
run like you did before the tire change. If the fuel mileage offsets the
cost of the higher octane fuel, then that is the best way to go. Some
vehicles will see a good increase in mileage if the fuel allows it to be
run in the higher gear. The only way you can know for sure is to test
your particular vehicle.
Chris
09-18-2007, 06:10 AM
#142
Guest
Posts: n/a
Re: ACCURATE SPEEDOMETER?
On Mon, 17 Sep 2007 14:53:07 -0400, SnoMan <admin@snoman.com> wrote:
>On Mon, 17 Sep 2007 12:52:55 -0500, c <c@me.org> wrote:
>
>>Um, your statement is quite wrong. For instance, overdrive on my truck
>>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
>>sooner if I choose to never use it. I will agree with you on the lugging
>>part, especially if it causes pinging, but no, I will not sit here and
>>agree with you that my engine will last just as long turning 3000 RPM as
>>it does turning 2100 RPM. That's insane.
>
>
>Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
>with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
>excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
>all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
>that when 220K with a 3000 to 3500 RPM cruise and more and was using
>a quart maybe every 3500 miles then. Also true RPM drop is determined
>by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
>4L60 or .69 on a Ally 5 speed)
>-----------------
>TheSnoMan.com
Hey Snow, look out! There's another dead horse. Better get your
baseball bat.
--
Old Crow "Yol Bolson!"
'82 FLTC-P "Miss Pearl"
'95 YJ Rio Grande
BS#133, SENS, TOMKAT, MAMBM
--
Posted via a free Usenet account from http://www.teranews.com
>On Mon, 17 Sep 2007 12:52:55 -0500, c <c@me.org> wrote:
>
>>Um, your statement is quite wrong. For instance, overdrive on my truck
>>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
>>sooner if I choose to never use it. I will agree with you on the lugging
>>part, especially if it causes pinging, but no, I will not sit here and
>>agree with you that my engine will last just as long turning 3000 RPM as
>>it does turning 2100 RPM. That's insane.
>
>
>Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
>with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
>excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
>all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
>that when 220K with a 3000 to 3500 RPM cruise and more and was using
>a quart maybe every 3500 miles then. Also true RPM drop is determined
>by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
>4L60 or .69 on a Ally 5 speed)
>-----------------
>TheSnoMan.com
Hey Snow, look out! There's another dead horse. Better get your
baseball bat.
--
Old Crow "Yol Bolson!"
'82 FLTC-P "Miss Pearl"
'95 YJ Rio Grande
BS#133, SENS, TOMKAT, MAMBM
--
Posted via a free Usenet account from http://www.teranews.com
09-18-2007, 06:10 AM
#143
Guest
Posts: n/a
Re: ACCURATE SPEEDOMETER?
On Mon, 17 Sep 2007 14:53:07 -0400, SnoMan <admin@snoman.com> wrote:
>On Mon, 17 Sep 2007 12:52:55 -0500, c <c@me.org> wrote:
>
>>Um, your statement is quite wrong. For instance, overdrive on my truck
>>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
>>sooner if I choose to never use it. I will agree with you on the lugging
>>part, especially if it causes pinging, but no, I will not sit here and
>>agree with you that my engine will last just as long turning 3000 RPM as
>>it does turning 2100 RPM. That's insane.
>
>
>Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
>with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
>excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
>all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
>that when 220K with a 3000 to 3500 RPM cruise and more and was using
>a quart maybe every 3500 miles then. Also true RPM drop is determined
>by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
>4L60 or .69 on a Ally 5 speed)
>-----------------
>TheSnoMan.com
Hey Snow, look out! There's another dead horse. Better get your
baseball bat.
--
Old Crow "Yol Bolson!"
'82 FLTC-P "Miss Pearl"
'95 YJ Rio Grande
BS#133, SENS, TOMKAT, MAMBM
--
Posted via a free Usenet account from http://www.teranews.com
>On Mon, 17 Sep 2007 12:52:55 -0500, c <c@me.org> wrote:
>
>>Um, your statement is quite wrong. For instance, overdrive on my truck
>>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
>>sooner if I choose to never use it. I will agree with you on the lugging
>>part, especially if it causes pinging, but no, I will not sit here and
>>agree with you that my engine will last just as long turning 3000 RPM as
>>it does turning 2100 RPM. That's insane.
>
>
>Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
>with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
>excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
>all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
>that when 220K with a 3000 to 3500 RPM cruise and more and was using
>a quart maybe every 3500 miles then. Also true RPM drop is determined
>by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
>4L60 or .69 on a Ally 5 speed)
>-----------------
>TheSnoMan.com
Hey Snow, look out! There's another dead horse. Better get your
baseball bat.
--
Old Crow "Yol Bolson!"
'82 FLTC-P "Miss Pearl"
'95 YJ Rio Grande
BS#133, SENS, TOMKAT, MAMBM
--
Posted via a free Usenet account from http://www.teranews.com
09-18-2007, 06:10 AM
#144
Guest
Posts: n/a
Re: ACCURATE SPEEDOMETER?
On Mon, 17 Sep 2007 14:53:07 -0400, SnoMan <admin@snoman.com> wrote:
>On Mon, 17 Sep 2007 12:52:55 -0500, c <c@me.org> wrote:
>
>>Um, your statement is quite wrong. For instance, overdrive on my truck
>>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
>>sooner if I choose to never use it. I will agree with you on the lugging
>>part, especially if it causes pinging, but no, I will not sit here and
>>agree with you that my engine will last just as long turning 3000 RPM as
>>it does turning 2100 RPM. That's insane.
>
>
>Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
>with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
>excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
>all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
>that when 220K with a 3000 to 3500 RPM cruise and more and was using
>a quart maybe every 3500 miles then. Also true RPM drop is determined
>by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
>4L60 or .69 on a Ally 5 speed)
>-----------------
>TheSnoMan.com
Hey Snow, look out! There's another dead horse. Better get your
baseball bat.
--
Old Crow "Yol Bolson!"
'82 FLTC-P "Miss Pearl"
'95 YJ Rio Grande
BS#133, SENS, TOMKAT, MAMBM
--
Posted via a free Usenet account from http://www.teranews.com
>On Mon, 17 Sep 2007 12:52:55 -0500, c <c@me.org> wrote:
>
>>Um, your statement is quite wrong. For instance, overdrive on my truck
>>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
>>sooner if I choose to never use it. I will agree with you on the lugging
>>part, especially if it causes pinging, but no, I will not sit here and
>>agree with you that my engine will last just as long turning 3000 RPM as
>>it does turning 2100 RPM. That's insane.
>
>
>Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
>with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
>excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
>all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
>that when 220K with a 3000 to 3500 RPM cruise and more and was using
>a quart maybe every 3500 miles then. Also true RPM drop is determined
>by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
>4L60 or .69 on a Ally 5 speed)
>-----------------
>TheSnoMan.com
Hey Snow, look out! There's another dead horse. Better get your
baseball bat.
--
Old Crow "Yol Bolson!"
'82 FLTC-P "Miss Pearl"
'95 YJ Rio Grande
BS#133, SENS, TOMKAT, MAMBM
--
Posted via a free Usenet account from http://www.teranews.com
09-18-2007, 06:10 AM
#145
Guest
Posts: n/a
Re: ACCURATE SPEEDOMETER?
On Mon, 17 Sep 2007 14:53:07 -0400, SnoMan <admin@snoman.com> wrote:
>On Mon, 17 Sep 2007 12:52:55 -0500, c <c@me.org> wrote:
>
>>Um, your statement is quite wrong. For instance, overdrive on my truck
>>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
>>sooner if I choose to never use it. I will agree with you on the lugging
>>part, especially if it causes pinging, but no, I will not sit here and
>>agree with you that my engine will last just as long turning 3000 RPM as
>>it does turning 2100 RPM. That's insane.
>
>
>Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
>with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
>excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
>all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
>that when 220K with a 3000 to 3500 RPM cruise and more and was using
>a quart maybe every 3500 miles then. Also true RPM drop is determined
>by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
>4L60 or .69 on a Ally 5 speed)
>-----------------
>TheSnoMan.com
Hey Snow, look out! There's another dead horse. Better get your
baseball bat.
--
Old Crow "Yol Bolson!"
'82 FLTC-P "Miss Pearl"
'95 YJ Rio Grande
BS#133, SENS, TOMKAT, MAMBM
--
Posted via a free Usenet account from http://www.teranews.com
>On Mon, 17 Sep 2007 12:52:55 -0500, c <c@me.org> wrote:
>
>>Um, your statement is quite wrong. For instance, overdrive on my truck
>>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
>>sooner if I choose to never use it. I will agree with you on the lugging
>>part, especially if it causes pinging, but no, I will not sit here and
>>agree with you that my engine will last just as long turning 3000 RPM as
>>it does turning 2100 RPM. That's insane.
>
>
>Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
>with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
>excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
>all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
>that when 220K with a 3000 to 3500 RPM cruise and more and was using
>a quart maybe every 3500 miles then. Also true RPM drop is determined
>by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
>4L60 or .69 on a Ally 5 speed)
>-----------------
>TheSnoMan.com
Hey Snow, look out! There's another dead horse. Better get your
baseball bat.
--
Old Crow "Yol Bolson!"
'82 FLTC-P "Miss Pearl"
'95 YJ Rio Grande
BS#133, SENS, TOMKAT, MAMBM
--
Posted via a free Usenet account from http://www.teranews.com
09-18-2007, 08:48 AM
#146
Guest
Posts: n/a
Re: ACCURATE SPEEDOMETER?
On Sep 18, 6:10 am, Old Crow <wallisc...@yahoo.com> wrote:
> On Mon, 17 Sep 2007 14:53:07 -0400, SnoMan <ad...@snoman.com> wrote:
> >On Mon, 17 Sep 2007 12:52:55 -0500, c <c...@me.org> wrote:
>
> >>Um, your statement is quite wrong. For instance, overdrive on my truck
> >>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
> >>sooner if I choose to never use it. I will agree with you on the lugging
> >>part, especially if it causes pinging, but no, I will not sit here and
> >>agree with you that my engine will last just as long turning 3000 RPM as
> >>it does turning 2100 RPM. That's insane.
>
> >Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
> >with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
> >excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
> >all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
> >that when 220K with a 3000 to 3500 RPM cruise and more and was using
> >a quart maybe every 3500 miles then. Also true RPM drop is determined
> >by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
> >4L60 or .69 on a Ally 5 speed)
> >-----------------
> >TheSnoMan.com
>
> Hey Snow, look out! There's another dead horse. Better get your
> baseball bat.
> --
> Old Crow "Yol Bolson!"
> '82 FLTC-P "Miss Pearl"
> '95 YJ Rio Grande
> BS#133, SENS, TOMKAT, MAMBM
>
> --
> Posted via a free Usenet account fromhttp://www.teranews.com- Hide quoted text -
>
> - Show quoted text -
Thanks Chris. That was helpful. :)
I will just have to remember to fill my tank with 89 octane instead of
87. Is there much of a difference in effectiveness between the 89 and
93 as far as pinging is concerned?
> On Mon, 17 Sep 2007 14:53:07 -0400, SnoMan <ad...@snoman.com> wrote:
> >On Mon, 17 Sep 2007 12:52:55 -0500, c <c...@me.org> wrote:
>
> >>Um, your statement is quite wrong. For instance, overdrive on my truck
> >>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
> >>sooner if I choose to never use it. I will agree with you on the lugging
> >>part, especially if it causes pinging, but no, I will not sit here and
> >>agree with you that my engine will last just as long turning 3000 RPM as
> >>it does turning 2100 RPM. That's insane.
>
> >Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
> >with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
> >excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
> >all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
> >that when 220K with a 3000 to 3500 RPM cruise and more and was using
> >a quart maybe every 3500 miles then. Also true RPM drop is determined
> >by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
> >4L60 or .69 on a Ally 5 speed)
> >-----------------
> >TheSnoMan.com
>
> Hey Snow, look out! There's another dead horse. Better get your
> baseball bat.
> --
> Old Crow "Yol Bolson!"
> '82 FLTC-P "Miss Pearl"
> '95 YJ Rio Grande
> BS#133, SENS, TOMKAT, MAMBM
>
> --
> Posted via a free Usenet account fromhttp://www.teranews.com- Hide quoted text -
>
> - Show quoted text -
Thanks Chris. That was helpful. :)
I will just have to remember to fill my tank with 89 octane instead of
87. Is there much of a difference in effectiveness between the 89 and
93 as far as pinging is concerned?
09-18-2007, 08:48 AM
#147
Guest
Posts: n/a
Re: ACCURATE SPEEDOMETER?
On Sep 18, 6:10 am, Old Crow <wallisc...@yahoo.com> wrote:
> On Mon, 17 Sep 2007 14:53:07 -0400, SnoMan <ad...@snoman.com> wrote:
> >On Mon, 17 Sep 2007 12:52:55 -0500, c <c...@me.org> wrote:
>
> >>Um, your statement is quite wrong. For instance, overdrive on my truck
> >>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
> >>sooner if I choose to never use it. I will agree with you on the lugging
> >>part, especially if it causes pinging, but no, I will not sit here and
> >>agree with you that my engine will last just as long turning 3000 RPM as
> >>it does turning 2100 RPM. That's insane.
>
> >Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
> >with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
> >excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
> >all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
> >that when 220K with a 3000 to 3500 RPM cruise and more and was using
> >a quart maybe every 3500 miles then. Also true RPM drop is determined
> >by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
> >4L60 or .69 on a Ally 5 speed)
> >-----------------
> >TheSnoMan.com
>
> Hey Snow, look out! There's another dead horse. Better get your
> baseball bat.
> --
> Old Crow "Yol Bolson!"
> '82 FLTC-P "Miss Pearl"
> '95 YJ Rio Grande
> BS#133, SENS, TOMKAT, MAMBM
>
> --
> Posted via a free Usenet account fromhttp://www.teranews.com- Hide quoted text -
>
> - Show quoted text -
Thanks Chris. That was helpful. :)
I will just have to remember to fill my tank with 89 octane instead of
87. Is there much of a difference in effectiveness between the 89 and
93 as far as pinging is concerned?
> On Mon, 17 Sep 2007 14:53:07 -0400, SnoMan <ad...@snoman.com> wrote:
> >On Mon, 17 Sep 2007 12:52:55 -0500, c <c...@me.org> wrote:
>
> >>Um, your statement is quite wrong. For instance, overdrive on my truck
> >>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
> >>sooner if I choose to never use it. I will agree with you on the lugging
> >>part, especially if it causes pinging, but no, I will not sit here and
> >>agree with you that my engine will last just as long turning 3000 RPM as
> >>it does turning 2100 RPM. That's insane.
>
> >Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
> >with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
> >excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
> >all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
> >that when 220K with a 3000 to 3500 RPM cruise and more and was using
> >a quart maybe every 3500 miles then. Also true RPM drop is determined
> >by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
> >4L60 or .69 on a Ally 5 speed)
> >-----------------
> >TheSnoMan.com
>
> Hey Snow, look out! There's another dead horse. Better get your
> baseball bat.
> --
> Old Crow "Yol Bolson!"
> '82 FLTC-P "Miss Pearl"
> '95 YJ Rio Grande
> BS#133, SENS, TOMKAT, MAMBM
>
> --
> Posted via a free Usenet account fromhttp://www.teranews.com- Hide quoted text -
>
> - Show quoted text -
Thanks Chris. That was helpful. :)
I will just have to remember to fill my tank with 89 octane instead of
87. Is there much of a difference in effectiveness between the 89 and
93 as far as pinging is concerned?
09-18-2007, 08:48 AM
#148
Guest
Posts: n/a
Re: ACCURATE SPEEDOMETER?
On Sep 18, 6:10 am, Old Crow <wallisc...@yahoo.com> wrote:
> On Mon, 17 Sep 2007 14:53:07 -0400, SnoMan <ad...@snoman.com> wrote:
> >On Mon, 17 Sep 2007 12:52:55 -0500, c <c...@me.org> wrote:
>
> >>Um, your statement is quite wrong. For instance, overdrive on my truck
> >>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
> >>sooner if I choose to never use it. I will agree with you on the lugging
> >>part, especially if it causes pinging, but no, I will not sit here and
> >>agree with you that my engine will last just as long turning 3000 RPM as
> >>it does turning 2100 RPM. That's insane.
>
> >Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
> >with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
> >excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
> >all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
> >that when 220K with a 3000 to 3500 RPM cruise and more and was using
> >a quart maybe every 3500 miles then. Also true RPM drop is determined
> >by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
> >4L60 or .69 on a Ally 5 speed)
> >-----------------
> >TheSnoMan.com
>
> Hey Snow, look out! There's another dead horse. Better get your
> baseball bat.
> --
> Old Crow "Yol Bolson!"
> '82 FLTC-P "Miss Pearl"
> '95 YJ Rio Grande
> BS#133, SENS, TOMKAT, MAMBM
>
> --
> Posted via a free Usenet account fromhttp://www.teranews.com- Hide quoted text -
>
> - Show quoted text -
Thanks Chris. That was helpful. :)
I will just have to remember to fill my tank with 89 octane instead of
87. Is there much of a difference in effectiveness between the 89 and
93 as far as pinging is concerned?
> On Mon, 17 Sep 2007 14:53:07 -0400, SnoMan <ad...@snoman.com> wrote:
> >On Mon, 17 Sep 2007 12:52:55 -0500, c <c...@me.org> wrote:
>
> >>Um, your statement is quite wrong. For instance, overdrive on my truck
> >>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
> >>sooner if I choose to never use it. I will agree with you on the lugging
> >>part, especially if it causes pinging, but no, I will not sit here and
> >>agree with you that my engine will last just as long turning 3000 RPM as
> >>it does turning 2100 RPM. That's insane.
>
> >Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
> >with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
> >excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
> >all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
> >that when 220K with a 3000 to 3500 RPM cruise and more and was using
> >a quart maybe every 3500 miles then. Also true RPM drop is determined
> >by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
> >4L60 or .69 on a Ally 5 speed)
> >-----------------
> >TheSnoMan.com
>
> Hey Snow, look out! There's another dead horse. Better get your
> baseball bat.
> --
> Old Crow "Yol Bolson!"
> '82 FLTC-P "Miss Pearl"
> '95 YJ Rio Grande
> BS#133, SENS, TOMKAT, MAMBM
>
> --
> Posted via a free Usenet account fromhttp://www.teranews.com- Hide quoted text -
>
> - Show quoted text -
Thanks Chris. That was helpful. :)
I will just have to remember to fill my tank with 89 octane instead of
87. Is there much of a difference in effectiveness between the 89 and
93 as far as pinging is concerned?
09-18-2007, 08:48 AM
#149
Guest
Posts: n/a
Re: ACCURATE SPEEDOMETER?
On Sep 18, 6:10 am, Old Crow <wallisc...@yahoo.com> wrote:
> On Mon, 17 Sep 2007 14:53:07 -0400, SnoMan <ad...@snoman.com> wrote:
> >On Mon, 17 Sep 2007 12:52:55 -0500, c <c...@me.org> wrote:
>
> >>Um, your statement is quite wrong. For instance, overdrive on my truck
> >>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
> >>sooner if I choose to never use it. I will agree with you on the lugging
> >>part, especially if it causes pinging, but no, I will not sit here and
> >>agree with you that my engine will last just as long turning 3000 RPM as
> >>it does turning 2100 RPM. That's insane.
>
> >Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
> >with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
> >excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
> >all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
> >that when 220K with a 3000 to 3500 RPM cruise and more and was using
> >a quart maybe every 3500 miles then. Also true RPM drop is determined
> >by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
> >4L60 or .69 on a Ally 5 speed)
> >-----------------
> >TheSnoMan.com
>
> Hey Snow, look out! There's another dead horse. Better get your
> baseball bat.
> --
> Old Crow "Yol Bolson!"
> '82 FLTC-P "Miss Pearl"
> '95 YJ Rio Grande
> BS#133, SENS, TOMKAT, MAMBM
>
> --
> Posted via a free Usenet account fromhttp://www.teranews.com- Hide quoted text -
>
> - Show quoted text -
Thanks Chris. That was helpful. :)
I will just have to remember to fill my tank with 89 octane instead of
87. Is there much of a difference in effectiveness between the 89 and
93 as far as pinging is concerned?
> On Mon, 17 Sep 2007 14:53:07 -0400, SnoMan <ad...@snoman.com> wrote:
> >On Mon, 17 Sep 2007 12:52:55 -0500, c <c...@me.org> wrote:
>
> >>Um, your statement is quite wrong. For instance, overdrive on my truck
> >>reduces the RPM by 30% so yeah I am pretty sure my engine will wear out
> >>sooner if I choose to never use it. I will agree with you on the lugging
> >>part, especially if it causes pinging, but no, I will not sit here and
> >>agree with you that my engine will last just as long turning 3000 RPM as
> >>it does turning 2100 RPM. That's insane.
>
> >Gee how did I put close to 200K and a few 4x4's 20 to 30 years ago
> >with 4.10 and 4.56 gears and no OD???? RPM as long as it is not
> >excessive (like 4000 to 5000 RPM cruises ) will not shorten life at
> >all. 2500 RPM or cruise for a V8 is childs play. How about a Toyota
> >that when 220K with a 3000 to 3500 RPM cruise and more and was using
> >a quart maybe every 3500 miles then. Also true RPM drop is determined
> >by OD ratio and to get a 30% drop you need a .7 (like on a 700R4 or
> >4L60 or .69 on a Ally 5 speed)
> >-----------------
> >TheSnoMan.com
>
> Hey Snow, look out! There's another dead horse. Better get your
> baseball bat.
> --
> Old Crow "Yol Bolson!"
> '82 FLTC-P "Miss Pearl"
> '95 YJ Rio Grande
> BS#133, SENS, TOMKAT, MAMBM
>
> --
> Posted via a free Usenet account fromhttp://www.teranews.com- Hide quoted text -
>
> - Show quoted text -
Thanks Chris. That was helpful. :)
I will just have to remember to fill my tank with 89 octane instead of
87. Is there much of a difference in effectiveness between the 89 and
93 as far as pinging is concerned?
09-18-2007, 10:07 AM
#150
Guest
Posts: n/a
Re: ACCURATE SPEEDOMETER?
c wrote:
> Tracie wrote:
>> On Sep 17, 10:36 pm, c <c...@me.org> wrote:
>>> Tracie wrote:
>>>> On Sep 17, 6:49 pm, twaldron <d...@hairsproutingbunions.com> wrote:
>>>>> Tracie wrote:
>>>>>> On Sep 17, 3:49 pm, "L.W. \(Bill\) ------ III"
>>>>>> <LWBillHug...@------.net> wrote:
>>>>>>> Doesn't your Rubicon automatically correct for tire size?
>>>>>>> Probably by
>>>>>>> this '06 it also measures the distance from the ground.
>>>>>>> God Bless America, Bill O|||||||O
>>>>>>> mailto:LW------...@aol.comhttp://www.----------.com/
>>>>>>> "twaldron" <d...@hairsproutingbunions.com> wrote in message
>>>>>>> news:WcxHi.1705$ec2.502@trnddc03...
>>>>>>>> Your minimal tire size increase likely made your speedo/odo more
>>>>>>>> accurate as they tend to read high from the manufacturer. That way
>>>>>>>> warranties expire sooner and manufacturers save money. I'd bet
>>>>>>>> you are
>>>>>>>> very close now. For fuel economy, use the highest gear you can
>>>>>>>> while
>>>>>>>> staying in the power band (not lugging). Lugging will become
>>>>>>>> immediately
>>>>>>>> apparent and you do it by feel, not by someone telling you what
>>>>>>>> RPM to
>>>>>>>> run. If you shift into too high a gear, you will notice a power
>>>>>>>> response
>>>>>>>> loss and ultimately your engine will lug. Downshift.
>>>>>>>> tw
>>>>>>> --
>>>>>>> Posted via a free Usenet account fromhttp://www.teranews.com
>>>>>> Well, I do have an appt at the dealership tomorrow around 5 pm
>>>>>> (eastern time). When I find out whether or not my speedo is right on
>>>>>> or off a few mph, I will certainly post the results to let you all
>>>>>> know. In the meantime, I really don't have a lugging issue or a
>>>>>> power
>>>>>> loss with the 3.07s and 31s. I can start up a moderate sized hill
>>>>>> doing 65 (according to the speedometer) in 5th gear, and not have to
>>>>>> stomp the gas pedal to continue going up the hill at a nice pace. I
>>>>>> am wondering if the spec sheet on my jeep is wrong, and I actually
>>>>>> have 3.73s. I will look at the rear diff case tonight and see what
>>>>>> the stamp says.
>>>>> Are you making a special trip to the dealer to check your speedo??
>>>>> tw- Hide quoted text -
>>>>> - Show quoted text -
>>>> Not really. I have had this appt scheduled for a few days now. I am
>>>> not really good at some things when it comes to this stuff. However,
>>>> I did try the measured mile trick on the way home tonight, and used
>>>> the formula that someone posted here earlier (3600/time it takes to go
>>>> 1 mile) = actual speed. When my speedometer reads 60, it took me 54
>>>> seconds to go 1 mile. Hence I am assuming my actual speed is
>>>> approximately 66.5 mph (3600/54=66.6).
>>>> As for the 3.73s, no such luck. : ( I am stuck with the 3.07s.
>>>> Although as I mentioned earlier, it's really not that bad. At least
>>>> not as bad as I had expected. There is a noticeable difference from
>>>> the stock sized tires, but I really don't notice it until I get into
>>>> 5th gear. Then again, before this 6 speed, I was used to driving a 5
>>>> speed anyway. And finally, there's the great debate of whether or not
>>>> to use 6th gear and if so, at what speed/rpm.
>>>> One thing.....what is engine pinging and what does it sound like? I
>>>> have a 'funny' noise that my jeep makes (seems to be coming from the
>>>> passenger side) while going uphill. To me, it sounds like keys
>>>> jingling very softly and intermittently. It never happened (that I
>>>> remember) prior to the installation of the bigger tires. The engine
>>>> is not skipping, sputtering, or seem to be lugging at all when this
>>>> noise occurs. It usually starts right at the beginning of a moderate
>>>> sized hill and continues intermittently until I get to the top of the
>>>> hill. And it NEVER happens when the engine is cold (first 30-45
>>>> minutes of driving hills or not) or while going downhill. I don't
>>>> know if this makes a difference, but I have been using 87 octane fuel
>>>> since I bought it new in November of 2006. Just to see if it made a
>>>> difference, I filled her up with 89 octane today. Gonna run her a
>>>> couple of days and see if I still notice this noise.
>>> The "key jingling" sound you hear is probably pinging. That is actually
>>> a good way to describe it. I used to always tell people it sounds like
>>> light tapping on a piece of metal with a small hammer.
>>>
>>> Chris- Hide quoted text -
>>>
>>> - Show quoted text -
>>
>>
>> Any idea why this would happen when I don't seem to be lugging the
>> engine? Could it be strictly related to the increased tire size? I
>> know how to 'feel' an engine to shift without lugging (been driving a
>> stick for the past 13 years) or to shift into a lower gear while going
>> uphill if engine seems to be lugging. Other than the 87 fuel I was
>> using, I have no clue. Is this harmful if it continues, and is there
>> a way to avoid it from happening? I drive approximately 35 minutes
>> each way to work, and it only happens 2-3 times each way for about 10
>> seconds each time (not a straight 10 seconds, but intermittently 2-3
>> times in that 10 seconds).
>>
>
> When your tire diameter increased, it effectively increases the load on
> the engine. Kind of like adding weight to the vehicle. Yes it is harmful
> to the engine if you let it keep happening. What you are actually
> hearing is the fuel igniting in the cylinder before it is supposed to.
> It is caused from excessive cylinder pressure. Over time it can cause
> broken pistons and piston rings, blown head gaskets, and in extreme
> cases, a cracked cylinder or head. Higher octane fuel will stop the
> pinging, as will keeping the transmission in a lower gear.
>
> What you can do to test the cost effectiveness of the high octane fuel
> is to run one tank of 87 octane while using the lower gear and check
> your fuel mileage. then do the same with 89 octane and see if you can
> run like you did before the tire change. If the fuel mileage offsets the
> cost of the higher octane fuel, then that is the best way to go. Some
> vehicles will see a good increase in mileage if the fuel allows it to be
> run in the higher gear. The only way you can know for sure is to test
> your particular vehicle.
>
> Chris
I agree. To me the light ping means lugging and bad mileage. Running
in a lower gear ups 'my' mileage radically when this is going on.
I also have a manually tuned carb engine with a 'hot' Accel powered
spark and hot timing curve so mine runs best on 91 or 92 octane.
In 'my' case, it makes 100 miles per tank difference in gas mileage so
it is well worth the extra for the high test.
In our old Cherokee 4.0's case, 91 octane gave slightly lower mileage if
anything at all. It liked regular.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
> Tracie wrote:
>> On Sep 17, 10:36 pm, c <c...@me.org> wrote:
>>> Tracie wrote:
>>>> On Sep 17, 6:49 pm, twaldron <d...@hairsproutingbunions.com> wrote:
>>>>> Tracie wrote:
>>>>>> On Sep 17, 3:49 pm, "L.W. \(Bill\) ------ III"
>>>>>> <LWBillHug...@------.net> wrote:
>>>>>>> Doesn't your Rubicon automatically correct for tire size?
>>>>>>> Probably by
>>>>>>> this '06 it also measures the distance from the ground.
>>>>>>> God Bless America, Bill O|||||||O
>>>>>>> mailto:LW------...@aol.comhttp://www.----------.com/
>>>>>>> "twaldron" <d...@hairsproutingbunions.com> wrote in message
>>>>>>> news:WcxHi.1705$ec2.502@trnddc03...
>>>>>>>> Your minimal tire size increase likely made your speedo/odo more
>>>>>>>> accurate as they tend to read high from the manufacturer. That way
>>>>>>>> warranties expire sooner and manufacturers save money. I'd bet
>>>>>>>> you are
>>>>>>>> very close now. For fuel economy, use the highest gear you can
>>>>>>>> while
>>>>>>>> staying in the power band (not lugging). Lugging will become
>>>>>>>> immediately
>>>>>>>> apparent and you do it by feel, not by someone telling you what
>>>>>>>> RPM to
>>>>>>>> run. If you shift into too high a gear, you will notice a power
>>>>>>>> response
>>>>>>>> loss and ultimately your engine will lug. Downshift.
>>>>>>>> tw
>>>>>>> --
>>>>>>> Posted via a free Usenet account fromhttp://www.teranews.com
>>>>>> Well, I do have an appt at the dealership tomorrow around 5 pm
>>>>>> (eastern time). When I find out whether or not my speedo is right on
>>>>>> or off a few mph, I will certainly post the results to let you all
>>>>>> know. In the meantime, I really don't have a lugging issue or a
>>>>>> power
>>>>>> loss with the 3.07s and 31s. I can start up a moderate sized hill
>>>>>> doing 65 (according to the speedometer) in 5th gear, and not have to
>>>>>> stomp the gas pedal to continue going up the hill at a nice pace. I
>>>>>> am wondering if the spec sheet on my jeep is wrong, and I actually
>>>>>> have 3.73s. I will look at the rear diff case tonight and see what
>>>>>> the stamp says.
>>>>> Are you making a special trip to the dealer to check your speedo??
>>>>> tw- Hide quoted text -
>>>>> - Show quoted text -
>>>> Not really. I have had this appt scheduled for a few days now. I am
>>>> not really good at some things when it comes to this stuff. However,
>>>> I did try the measured mile trick on the way home tonight, and used
>>>> the formula that someone posted here earlier (3600/time it takes to go
>>>> 1 mile) = actual speed. When my speedometer reads 60, it took me 54
>>>> seconds to go 1 mile. Hence I am assuming my actual speed is
>>>> approximately 66.5 mph (3600/54=66.6).
>>>> As for the 3.73s, no such luck. : ( I am stuck with the 3.07s.
>>>> Although as I mentioned earlier, it's really not that bad. At least
>>>> not as bad as I had expected. There is a noticeable difference from
>>>> the stock sized tires, but I really don't notice it until I get into
>>>> 5th gear. Then again, before this 6 speed, I was used to driving a 5
>>>> speed anyway. And finally, there's the great debate of whether or not
>>>> to use 6th gear and if so, at what speed/rpm.
>>>> One thing.....what is engine pinging and what does it sound like? I
>>>> have a 'funny' noise that my jeep makes (seems to be coming from the
>>>> passenger side) while going uphill. To me, it sounds like keys
>>>> jingling very softly and intermittently. It never happened (that I
>>>> remember) prior to the installation of the bigger tires. The engine
>>>> is not skipping, sputtering, or seem to be lugging at all when this
>>>> noise occurs. It usually starts right at the beginning of a moderate
>>>> sized hill and continues intermittently until I get to the top of the
>>>> hill. And it NEVER happens when the engine is cold (first 30-45
>>>> minutes of driving hills or not) or while going downhill. I don't
>>>> know if this makes a difference, but I have been using 87 octane fuel
>>>> since I bought it new in November of 2006. Just to see if it made a
>>>> difference, I filled her up with 89 octane today. Gonna run her a
>>>> couple of days and see if I still notice this noise.
>>> The "key jingling" sound you hear is probably pinging. That is actually
>>> a good way to describe it. I used to always tell people it sounds like
>>> light tapping on a piece of metal with a small hammer.
>>>
>>> Chris- Hide quoted text -
>>>
>>> - Show quoted text -
>>
>>
>> Any idea why this would happen when I don't seem to be lugging the
>> engine? Could it be strictly related to the increased tire size? I
>> know how to 'feel' an engine to shift without lugging (been driving a
>> stick for the past 13 years) or to shift into a lower gear while going
>> uphill if engine seems to be lugging. Other than the 87 fuel I was
>> using, I have no clue. Is this harmful if it continues, and is there
>> a way to avoid it from happening? I drive approximately 35 minutes
>> each way to work, and it only happens 2-3 times each way for about 10
>> seconds each time (not a straight 10 seconds, but intermittently 2-3
>> times in that 10 seconds).
>>
>
> When your tire diameter increased, it effectively increases the load on
> the engine. Kind of like adding weight to the vehicle. Yes it is harmful
> to the engine if you let it keep happening. What you are actually
> hearing is the fuel igniting in the cylinder before it is supposed to.
> It is caused from excessive cylinder pressure. Over time it can cause
> broken pistons and piston rings, blown head gaskets, and in extreme
> cases, a cracked cylinder or head. Higher octane fuel will stop the
> pinging, as will keeping the transmission in a lower gear.
>
> What you can do to test the cost effectiveness of the high octane fuel
> is to run one tank of 87 octane while using the lower gear and check
> your fuel mileage. then do the same with 89 octane and see if you can
> run like you did before the tire change. If the fuel mileage offsets the
> cost of the higher octane fuel, then that is the best way to go. Some
> vehicles will see a good increase in mileage if the fuel allows it to be
> run in the higher gear. The only way you can know for sure is to test
> your particular vehicle.
>
> Chris
I agree. To me the light ping means lugging and bad mileage. Running
in a lower gear ups 'my' mileage radically when this is going on.
I also have a manually tuned carb engine with a 'hot' Accel powered
spark and hot timing curve so mine runs best on 91 or 92 octane.
In 'my' case, it makes 100 miles per tank difference in gas mileage so
it is well worth the extra for the high test.
In our old Cherokee 4.0's case, 91 octane gave slightly lower mileage if
anything at all. It liked regular.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)