when i was a kid (don't ask how long ago that was), i remember that the headers i put on my V-8 67 Mustang not only bumped my power up about 10%, but also improved MILEAGE by a similar amount - of course, that was dependant on me not keeping the pedal to the metal to constantly exploit my newfound power.

then a few weeks ago i heard a car show on the radio in which they talked about milking the last bit of mileage out of some big V-8 in a truck. with a better intake and freer-flowing catback system, the guy said his mileage went up around 20%!!!

are any of you getting better mileage due to intake/exhaust mods?

Ps - anyone using these OBX headers? how are they, and are they 49-state legal?

http://cgi.ebay.com/ebaymotors/OBX-R...QQcmdZViewItem

 

Not an expert but anything that would make a car faster to me would make it suck up more gas. When you have more flow and less restrictions, I would think that it would consume more gas.

 

Intake/exhaust mods basically allow the engine to become more adiabatically efficient. Less power wasted on the in/out side of things, which allows more power to be obtained from the same ammount of fuel.

This does increase milage if you drive the same. Don't expect 20% or anything close though. You might reasonably expect 3-5%.

 

I heard that the engine does not work as hard with mods that eliminate restriction, thus using less gas. I have an intake and when I drive like a regular person, it seems to save about 1~2mpg.

 

It all depends on your driving style though for me, completely stock I would get 30+ mpg with a peak of 33, the highest I've ever gotten since that with the mods is 28 peak 30.

 

If there is any "improvement" it will be very minimal. Less restrictions would "improve" a little bit. It more dependant on your right foot, and maintiance.

 

NOS increases mileage

 

Yes, they increase mileage however people rarely see the gains b/c of increased "spirited" driving

 

If there isn't any written documentation of the gain, dont go for it..

 

20% is high, sure in a computer slimulated world it might be 20% more effective. But in real world things are way less so yes maybe 5% but if you keep on it gas as said before not a chance. Boy i sure try to sound smart

 

I havent noticed an increase in my gas mileage. I was talking to a friend of mine who owns a 97 Maxima and he gets around 400 to the tank, but almost always highway driving. I get 300 usually to the tank..maybe a little bit more if its highway driving. I have an intake, ypipe and catback and the other day I got 370 to the tank...but about 270 of that was one trip all highway. haha when i came back to normal stop and go traffic with half a tank left, i only got alil bit over 100miles out of it.

 

well put.....the freeer intake and exhaust track = more efficency out of the motor...but yes u will tend to go WOT more often than not

 

I get about the same milege as i did when i was stock, but i do drive my car harder now too. When I switch to my brother's maxima which is stock, i get much worse milege than i do in my car doing the same type of driving. It improved but i don't necesarrily get better milege because of my driving style

 

I'm going to be looking for better highway mileage when I slap on my y/catback this summer, but I'm not expecting any miracles for city driving...

 

Since i put mods on my car (intake/exhaust) my cars MPG has gone down 20%. The sound of the intake and exhaust at WOT is addicting

 

My mileage has went up in highway driving because of less restriction. I also has a crimped resonator issue and replaced it. I think sometimes little things here and there help with the mileage. Tire pressure, clean throttle body, synthetic engine and tranny oil. Drove cross country and it did very good on gas.

 

NOS increases mileage........
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