High Flow Cats. would it affect my mpg?
#1
High Flow Cats. would it affect my mpg?
im just wondering if my high flow cats are affecting my mpg for my car. i only get 10-12 mpg per gallon on local or highway and thats not even driving aggressively. do anyone have an idea why this is happening?
#4
I have a 08 5AT with 29k mi, running 89 or 91 octane.
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#8
I have the same problem. Rarely do I see 12, most of the time its 10-11. Ive only had the car for about a month and I thought there was something wrong with it. The only mod I have is KN dropins. I do not drive aggressive at all. I would love to get up to around 17mpg.
I have a 08 5AT with 29k mi, running 89 or 91 octane.
I have a 08 5AT with 29k mi, running 89 or 91 octane.
do your have high flow cats?
and yes my tire pressure are perfect. i only run 93 octane and its a 08 g37s coupe at
#9
I have had HFC's for a while on my car, and they affected MPG in no way whatsoever. Just sound and drone. You might be confusing your HFC's with an mileage effect coming from another issue. If all's done right, you shouldn't have any noticeable MPG changes.
#10
#11
In Australia the basic/cheapest fuel is 93octane with premium being 95 octane and the highest (that I put in my 370gt) 98 octane (BP Ultimate or Shell Vpower). Is there some sort of conversion that should be done or is the fuel in the US just lower quality?
#12
Registered User
There is a formula. The octane rating in Aus is the RON (research octane number). In the US it is shown as the average of the RON and the MON (Motor Octane Number) The actual fuel is not that different in octane.
#13
Minnesota G owners
I added Cats as my first mod, but I of course ended up losing mileage overall since I was accelerating more to hear it. So do be careful, but it will improve your mileage and give you some extra torque. I would say that the HFC are one of the most restrictive parts of the exhaust
#14
Thanks for clearing that up. I have been told on numerous occasions that Japanese fuel is higher quality than Australian fuel so I found it hard to believe that the US fuel would be of a lower quality.
#15
i spoke to a few shops and according to them, they said i need to get my computer remapped to accept the new cats. the computer is reading that too much free air is passing tho, so its dumping more fuel into the motor.