Since I know there is an abundance of Carsound, etc. equipped owners in this forum I figure this is best place to post.

My question is. How has a 2.25 or 2.5'' high-flow cat affected your gas milage? I have heard from someone that having a high-flow cat or a test pipe decreased gas milage noticably. I haven't heard complaints before, so what are your experiences? Does it hurt lowend also, because I personally can't really think of a reason why it would hurt gas milage unless it took more throttal to get going...

BTW, I love and respect ITR's

 

No adverse affects at all. Saturday road trip = 30-31 mpg... same as with the test pipe. I am sure my "on track" gas mileage will be different.

I did notice a little bit of power loss on the top end.
Low end is better!

Plus no CEL

Willis

 

That's odd, I always thought it was the opposite.

 

Mike,

I think he was comparing the cat to a test pipe. I have not noticed any major difference. Granted, I have only had mine on for a week, but the mileage seems the same. I am making a pretty long trip tomorrow so I will know for sure.

 

Mines a 2.5 Carsound 9004 and I haven't felt or seen any adverse affects associated with mileage. I think that my mileage might suffer based only on the fact that I tend to spend more time in Vtec where my header performs so much better than stock.

I mean my mileage has gotten better from day one "of owning the car," and I notice it is certainly less than my old Ls used to be but, hey it's a performance car and mileage while being important is NOT the most important part of my satisfaction while I own my R.

I experienced better mileage on long trips with full I/H/E on my Ls and would expect the same or similar results with my R, "though I haven't recorded or tested this theory out yet." I mean I added the intake, header and cat to boost my HP and TQ, and with the R it just stands to reason that when you live in the high-end of Vtec more often that gas mileage is substantially less than hen driven more mild mannered.

IMHO of course,

A.

PS
1. intake= happy but not neccesary
2. JDM header= a big difference from stock
3. 2.5 cat= neccessary but, JDM cat was also an option

 

Also,

I feel absolutely NO loss in any part of my powerband. I have only experienced gains especially after Vtec engages and in the upper-end. It's not been dynoed yet but thats coming shortly.

A.

 

Thats false the high flow cat gives better gas milage. Probably some dumb ****** that told you that.

 

I averaged 37.3mpg on my carsound cat equipped car last weekend for a distance of over 2,030 miles. I'd say that it didn't hurt my mileage

Tom
I also passed emissions with this cat on.

 

Wow