'98 XJ 4.0L benefit of headers?
 

Hello, group -
While crawling under my XJ 4.0L, I have been amazed by the degree to
which the downpipe from the exhaust manifold is collapsed. It is 2/3
shut at the bend.

I have mentioned this at both the local 4WD shop and at the dealership
parts counter, and the replies have been something to the effect that
"Those 4 Litres seem to like the restriction", to "That's normal.
They're all formed like that".

When I read about modifications for power, those most popular seem to
be (not necessarily in their order):
1. Replace cat-back
2. Headers
3. Bored-out throttle body
4. low-restriction intake

What do the experts on this board think? Does this engine really
benefit from headers,since it seems as though it was engineered for
significant back-pressure?

Thanks.

jim

Re: '98 XJ 4.0L benefit of headers?
 

The 4.0 in my opinion has quite a bit of power for a V6. But I would also
like to find out some little mods to get some edge


<98XJ> wrote in message news:7le9u2tlu4gbsriefjcaf4kit0rj504b6p@4ax.com...
> Hello, group -
> While crawling under my XJ 4.0L, I have been amazed by the degree to
> which the downpipe from the exhaust manifold is collapsed. It is 2/3
> shut at the bend.
>
> I have mentioned this at both the local 4WD shop and at the dealership
> parts counter, and the replies have been something to the effect that
> "Those 4 Litres seem to like the restriction", to "That's normal.
> They're all formed like that".
>
> When I read about modifications for power, those most popular seem to
> be (not necessarily in their order):
> 1. Replace cat-back
> 2. Headers
> 3. Bored-out throttle body
> 4. low-restriction intake
>
> What do the experts on this board think? Does this engine really
> benefit from headers,since it seems as though it was engineered for
> significant back-pressure?
>
> Thanks.
>
> jim

Re: '98 XJ 4.0L benefit of headers?
 

The 4.0 in my opinion has quite a bit of power for a V6. But I would also
like to find out some little mods to get some edge


<98XJ> wrote in message news:7le9u2tlu4gbsriefjcaf4kit0rj504b6p@4ax.com...
> Hello, group -
> While crawling under my XJ 4.0L, I have been amazed by the degree to
> which the downpipe from the exhaust manifold is collapsed. It is 2/3
> shut at the bend.
>
> I have mentioned this at both the local 4WD shop and at the dealership
> parts counter, and the replies have been something to the effect that
> "Those 4 Litres seem to like the restriction", to "That's normal.
> They're all formed like that".
>
> When I read about modifications for power, those most popular seem to
> be (not necessarily in their order):
> 1. Replace cat-back
> 2. Headers
> 3. Bored-out throttle body
> 4. low-restriction intake
>
> What do the experts on this board think? Does this engine really
> benefit from headers,since it seems as though it was engineered for
> significant back-pressure?
>
> Thanks.
>
> jim

Re: '98 XJ 4.0L benefit of headers?
 

The 4.0 in my opinion has quite a bit of power for a V6. But I would also
like to find out some little mods to get some edge


<98XJ> wrote in message news:7le9u2tlu4gbsriefjcaf4kit0rj504b6p@4ax.com...
> Hello, group -
> While crawling under my XJ 4.0L, I have been amazed by the degree to
> which the downpipe from the exhaust manifold is collapsed. It is 2/3
> shut at the bend.
>
> I have mentioned this at both the local 4WD shop and at the dealership
> parts counter, and the replies have been something to the effect that
> "Those 4 Litres seem to like the restriction", to "That's normal.
> They're all formed like that".
>
> When I read about modifications for power, those most popular seem to
> be (not necessarily in their order):
> 1. Replace cat-back
> 2. Headers
> 3. Bored-out throttle body
> 4. low-restriction intake
>
> What do the experts on this board think? Does this engine really
> benefit from headers,since it seems as though it was engineered for
> significant back-pressure?
>
> Thanks.
>
> jim

Re: '98 XJ 4.0L benefit of headers?
 

My 4.0 is the Inline 6, not a V-6.

On Wed, 28 Feb 2007 00:00:09 GMT, "abomb69" <abuse@verizon.net> wrote:

>The 4.0 in my opinion has quite a bit of power for a V6. But I would also
>like to find out some little mods to get some edge
>
>
><98XJ> wrote in message news:7le9u2tlu4gbsriefjcaf4kit0rj504b6p@4ax.com...
>> Hello, group -
>> While crawling under my XJ 4.0L, I have been amazed by the degree to
>> which the downpipe from the exhaust manifold is collapsed. It is 2/3
>> shut at the bend.
>>
>> I have mentioned this at both the local 4WD shop and at the dealership
>> parts counter, and the replies have been something to the effect that
>> "Those 4 Litres seem to like the restriction", to "That's normal.
>> They're all formed like that".
>>
>> When I read about modifications for power, those most popular seem to
>> be (not necessarily in their order):
>> 1. Replace cat-back
>> 2. Headers
>> 3. Bored-out throttle body
>> 4. low-restriction intake
>>
>> What do the experts on this board think? Does this engine really
>> benefit from headers,since it seems as though it was engineered for
>> significant back-pressure?
>>
>> Thanks.
>>
>> jim
>

Re: '98 XJ 4.0L benefit of headers?
 

My 4.0 is the Inline 6, not a V-6.

On Wed, 28 Feb 2007 00:00:09 GMT, "abomb69" <abuse@verizon.net> wrote:

>The 4.0 in my opinion has quite a bit of power for a V6. But I would also
>like to find out some little mods to get some edge
>
>
><98XJ> wrote in message news:7le9u2tlu4gbsriefjcaf4kit0rj504b6p@4ax.com...
>> Hello, group -
>> While crawling under my XJ 4.0L, I have been amazed by the degree to
>> which the downpipe from the exhaust manifold is collapsed. It is 2/3
>> shut at the bend.
>>
>> I have mentioned this at both the local 4WD shop and at the dealership
>> parts counter, and the replies have been something to the effect that
>> "Those 4 Litres seem to like the restriction", to "That's normal.
>> They're all formed like that".
>>
>> When I read about modifications for power, those most popular seem to
>> be (not necessarily in their order):
>> 1. Replace cat-back
>> 2. Headers
>> 3. Bored-out throttle body
>> 4. low-restriction intake
>>
>> What do the experts on this board think? Does this engine really
>> benefit from headers,since it seems as though it was engineered for
>> significant back-pressure?
>>
>> Thanks.
>>
>> jim
>

Re: '98 XJ 4.0L benefit of headers?
 

My 4.0 is the Inline 6, not a V-6.

On Wed, 28 Feb 2007 00:00:09 GMT, "abomb69" <abuse@verizon.net> wrote:

>The 4.0 in my opinion has quite a bit of power for a V6. But I would also
>like to find out some little mods to get some edge
>
>
><98XJ> wrote in message news:7le9u2tlu4gbsriefjcaf4kit0rj504b6p@4ax.com...
>> Hello, group -
>> While crawling under my XJ 4.0L, I have been amazed by the degree to
>> which the downpipe from the exhaust manifold is collapsed. It is 2/3
>> shut at the bend.
>>
>> I have mentioned this at both the local 4WD shop and at the dealership
>> parts counter, and the replies have been something to the effect that
>> "Those 4 Litres seem to like the restriction", to "That's normal.
>> They're all formed like that".
>>
>> When I read about modifications for power, those most popular seem to
>> be (not necessarily in their order):
>> 1. Replace cat-back
>> 2. Headers
>> 3. Bored-out throttle body
>> 4. low-restriction intake
>>
>> What do the experts on this board think? Does this engine really
>> benefit from headers,since it seems as though it was engineered for
>> significant back-pressure?
>>
>> Thanks.
>>
>> jim
>

Re: '98 XJ 4.0L benefit of headers?
 

98XJ wrote:
> Hello, group -
> While crawling under my XJ 4.0L, I have been amazed by the degree to
> which the downpipe from the exhaust manifold is collapsed. It is 2/3
> shut at the bend.
>
> I have mentioned this at both the local 4WD shop and at the dealership
> parts counter, and the replies have been something to the effect that
> "Those 4 Litres seem to like the restriction", to "That's normal.
> They're all formed like that".
>
> When I read about modifications for power, those most popular seem to
> be (not necessarily in their order):
> 1. Replace cat-back
> 2. Headers
> 3. Bored-out throttle body
> 4. low-restriction intake
>
> What do the experts on this board think? Does this engine really
> benefit from headers,since it seems as though it was engineered for
> significant back-pressure?
>
> Thanks.
>
> jim

Well when I had a custom straight pipe with a high flow Dynomax Turbo
muffler put on my CJ7's 258, they did a smooth bend instead of the kink
bend that was there on the downpipe and I sure thought I got a power
increase. I also think I got 2" pipes.

It sure sounds nice anyway....

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
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)

Re: '98 XJ 4.0L benefit of headers?
 

98XJ wrote:
> Hello, group -
> While crawling under my XJ 4.0L, I have been amazed by the degree to
> which the downpipe from the exhaust manifold is collapsed. It is 2/3
> shut at the bend.
>
> I have mentioned this at both the local 4WD shop and at the dealership
> parts counter, and the replies have been something to the effect that
> "Those 4 Litres seem to like the restriction", to "That's normal.
> They're all formed like that".
>
> When I read about modifications for power, those most popular seem to
> be (not necessarily in their order):
> 1. Replace cat-back
> 2. Headers
> 3. Bored-out throttle body
> 4. low-restriction intake
>
> What do the experts on this board think? Does this engine really
> benefit from headers,since it seems as though it was engineered for
> significant back-pressure?
>
> Thanks.
>
> jim

Well when I had a custom straight pipe with a high flow Dynomax Turbo
muffler put on my CJ7's 258, they did a smooth bend instead of the kink
bend that was there on the downpipe and I sure thought I got a power
increase. I also think I got 2" pipes.

It sure sounds nice anyway....

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
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)

Re: '98 XJ 4.0L benefit of headers?
 

98XJ wrote:
> Hello, group -
> While crawling under my XJ 4.0L, I have been amazed by the degree to
> which the downpipe from the exhaust manifold is collapsed. It is 2/3
> shut at the bend.
>
> I have mentioned this at both the local 4WD shop and at the dealership
> parts counter, and the replies have been something to the effect that
> "Those 4 Litres seem to like the restriction", to "That's normal.
> They're all formed like that".
>
> When I read about modifications for power, those most popular seem to
> be (not necessarily in their order):
> 1. Replace cat-back
> 2. Headers
> 3. Bored-out throttle body
> 4. low-restriction intake
>
> What do the experts on this board think? Does this engine really
> benefit from headers,since it seems as though it was engineered for
> significant back-pressure?
>
> Thanks.
>
> jim

Well when I had a custom straight pipe with a high flow Dynomax Turbo
muffler put on my CJ7's 258, they did a smooth bend instead of the kink
bend that was there on the downpipe and I sure thought I got a power
increase. I also think I got 2" pipes.

It sure sounds nice anyway....

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
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)