Bone P.A. wrote:

> NO. As explained to me, @25mph on their dyno they look at wheel speed not
> mph or rpm. My tires is 33", sotck is less, they reference off stock. With
> larger tires you have lower rev's at low rev's engine run lean puts out more
> pollutants. Increase the rev less pollutants. Therefore smaller tires higher
> rev's less pollutants. My gearing is only 4.10

Alas, stock is not 4.10 either! So with the 33's and the 4.10 you are running
right about the right engine RPM for 31.4's, which is only 90% of 30's. If they
let you put stock tires on, while keeping the non-stock 4.10, it seems like
you've found a way to pass these tests even for engines that should fail it!

alan

 

Bone P.A. wrote:

> NO. As explained to me, @25mph on their dyno they look at wheel speed not
> mph or rpm. My tires is 33", sotck is less, they reference off stock. With
> larger tires you have lower rev's at low rev's engine run lean puts out more
> pollutants. Increase the rev less pollutants. Therefore smaller tires higher
> rev's less pollutants. My gearing is only 4.10

Alas, stock is not 4.10 either! So with the 33's and the 4.10 you are running
right about the right engine RPM for 31.4's, which is only 90% of 30's. If they
let you put stock tires on, while keeping the non-stock 4.10, it seems like
you've found a way to pass these tests even for engines that should fail it!

alan

 

Bone P.A. wrote:

> NO. As explained to me, @25mph on their dyno they look at wheel speed not
> mph or rpm. My tires is 33", sotck is less, they reference off stock. With
> larger tires you have lower rev's at low rev's engine run lean puts out more
> pollutants. Increase the rev less pollutants. Therefore smaller tires higher
> rev's less pollutants. My gearing is only 4.10

Alas, stock is not 4.10 either! So with the 33's and the 4.10 you are running
right about the right engine RPM for 31.4's, which is only 90% of 30's. If they
let you put stock tires on, while keeping the non-stock 4.10, it seems like
you've found a way to pass these tests even for engines that should fail it!

alan

 

Alan wrote:
>
> Bone P.A. wrote:
>
> > NO. As explained to me, @25mph on their dyno they look at wheel speed not
> > mph or rpm. My tires is 33", sotck is less, they reference off stock. With
> > larger tires you have lower rev's at low rev's engine run lean puts out more
> > pollutants. Increase the rev less pollutants. Therefore smaller tires higher
> > rev's less pollutants. My gearing is only 4.10
>
> Alas, stock is not 4.10 either! So with the 33's and the 4.10 you are running
> right about the right engine RPM for 31.4's, which is only 90% of 30's. If they
> let you put stock tires on, while keeping the non-stock 4.10, it seems like
> you've found a way to pass these tests even for engines that should fail it!
>
> alan

You know some days I am slower than others.

I just clued into the fact that the computer measures the roller speeds,
not the engine speeds...

Wow, that really cam make a difference in say a stock P215 and my
freaking 33's!

On mine there is a fast radical change in gas mileage vs rpm, so
emissions would be the same. My gas mileage sucks at low rpm.

Hmm, good to keep in mind.

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

 

Alan wrote:
>
> Bone P.A. wrote:
>
> > NO. As explained to me, @25mph on their dyno they look at wheel speed not
> > mph or rpm. My tires is 33", sotck is less, they reference off stock. With
> > larger tires you have lower rev's at low rev's engine run lean puts out more
> > pollutants. Increase the rev less pollutants. Therefore smaller tires higher
> > rev's less pollutants. My gearing is only 4.10
>
> Alas, stock is not 4.10 either! So with the 33's and the 4.10 you are running
> right about the right engine RPM for 31.4's, which is only 90% of 30's. If they
> let you put stock tires on, while keeping the non-stock 4.10, it seems like
> you've found a way to pass these tests even for engines that should fail it!
>
> alan

You know some days I am slower than others.

I just clued into the fact that the computer measures the roller speeds,
not the engine speeds...

Wow, that really cam make a difference in say a stock P215 and my
freaking 33's!

On mine there is a fast radical change in gas mileage vs rpm, so
emissions would be the same. My gas mileage sucks at low rpm.

Hmm, good to keep in mind.

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

 

Alan wrote:
>
> Bone P.A. wrote:
>
> > NO. As explained to me, @25mph on their dyno they look at wheel speed not
> > mph or rpm. My tires is 33", sotck is less, they reference off stock. With
> > larger tires you have lower rev's at low rev's engine run lean puts out more
> > pollutants. Increase the rev less pollutants. Therefore smaller tires higher
> > rev's less pollutants. My gearing is only 4.10
>
> Alas, stock is not 4.10 either! So with the 33's and the 4.10 you are running
> right about the right engine RPM for 31.4's, which is only 90% of 30's. If they
> let you put stock tires on, while keeping the non-stock 4.10, it seems like
> you've found a way to pass these tests even for engines that should fail it!
>
> alan

You know some days I am slower than others.

I just clued into the fact that the computer measures the roller speeds,
not the engine speeds...

Wow, that really cam make a difference in say a stock P215 and my
freaking 33's!

On mine there is a fast radical change in gas mileage vs rpm, so
emissions would be the same. My gas mileage sucks at low rpm.

Hmm, good to keep in mind.

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

 

Alan wrote:
>
> Bone P.A. wrote:
>
> > NO. As explained to me, @25mph on their dyno they look at wheel speed not
> > mph or rpm. My tires is 33", sotck is less, they reference off stock. With
> > larger tires you have lower rev's at low rev's engine run lean puts out more
> > pollutants. Increase the rev less pollutants. Therefore smaller tires higher
> > rev's less pollutants. My gearing is only 4.10
>
> Alas, stock is not 4.10 either! So with the 33's and the 4.10 you are running
> right about the right engine RPM for 31.4's, which is only 90% of 30's. If they
> let you put stock tires on, while keeping the non-stock 4.10, it seems like
> you've found a way to pass these tests even for engines that should fail it!
>
> alan

You know some days I am slower than others.

I just clued into the fact that the computer measures the roller speeds,
not the engine speeds...

Wow, that really cam make a difference in say a stock P215 and my
freaking 33's!

On mine there is a fast radical change in gas mileage vs rpm, so
emissions would be the same. My gas mileage sucks at low rpm.

Hmm, good to keep in mind.

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