99 Camaro 3.8 Five Speed MPG

**Chevyfan99** · 06-19-2008, 04:56 PM

Ive got a 99 Camaro with a 3.8 V6 and five Speed. Im trying to figure out the MPG Ill get on the freeway. aI have also added a K&N drop in filter and I have a Flowmaster 50 Series Muffler out back. Im trying to figure out how much the K&N and Flowmaster are going to help. What should I expect my MPGs to be? And also, I dont drive super easy and I dont beat the hell outta it, but I usually shift at 3000-3500 on average. Sorry if this is in the wrong spot. Any help would be appreciated thanks

**FreakV6** · 06-19-2008, 06:05 PM

it really can vary drasticly from car to car. when i was just intake and exhuast i could easily see 24-25mpg on the highway. However i have heard of some people only getting in the teens. It just depends on the maintaince you keep up, and a long list of other little things that can change it.

easiest way to tell is let your car run to almost empty. fill it up. remember how many gallons you get total. set ur trip meter to 0. once that tank is almost out, deived how many miles on the trip meter by how many gallons you got.

**Wesman** · 06-20-2008, 07:57 PM

I can average between 28MPH-32MPG on a trip in my 3.8 Grand Prix GTP. However, its S/C so it has a lower compression ratio which may help when cruising. Its also automatic and weighs more than your Camaro though, so I don't see why you wouldn't be able to get high 20's MPG on the highway if you drive conservatively. Unless you have some ridiculously short gears for some reason or something.

**FreakV6** · 06-23-2008, 06:12 AM

Wesman,

they biggest reason your getting that mpg is your gear ratio. a gtp runs 2.69 (i belive) gears, where we have a much higher gear ratio from stock. with him being a manual i belive his is a 3.23. However it is every possible for him to get mid to high 20's, like i said it all depends on his driving style and the up keep of the car.

**Wesman** · 06-23-2008, 07:55 PM

Originally Posted by lilchubby

Wesman,

they biggest reason your getting that mpg is your gear ratio. a gtp runs 2.69 (i belive) gears, where we have a much higher gear ratio from stock. with him being a manual i belive his is a 3.23. However it is every possible for him to get mid to high 20's, like i said it all depends on his driving style and the up keep of the car.

This is true.

However, I was figuring with his car weighing a couple hundred pounds less and the higher efficiency of the manual transmission, he could be close to the same numbers.

On the highway though, those 3.23's with the 5 speed will definitely drop the numbers down. My GTP only turns around 2,000RPM at 75MPH in 4th, which is nice.

**FreakV6** · 06-24-2008, 05:59 AM

Yea its still possible to get those numbers, just gonna be harder with the gearing. I should have the same gears as to OP and at 2k rpm in 5th im at about 65mph.

**b.lee** · 06-24-2008, 06:11 AM

shit, i got 26.6mpg last time i went up north.
didn't take the freeway though.
LS1 / A4 / 3.73 gear

**FreakV6** · 06-24-2008, 11:38 AM

b.lee thanks for contributing nothing.........

what rpm is that ls1 humming along at when cruzing like that...apples to oranges man apples to oranges.