Hey guys I am thinking about swapping my cam out on my SS but I would like to know what kind of gas mileage can I expect after this has been done. On my trip from out of town I got excellent gas mileage from my 2 1/2 hour trip I am aware that the added horsepower will decrease my mileage but by how much?? any way thanks for the input!!

 

a4 or m6?

 

233/233 cam
bolt ons
m6 trans
stock 10bolt with 3.42 gears

75-80mph with the windows down and ttops off (reduces mileage by about 1mpg) i consistently knock down 24-25mpg

 

with an m6 you will not loose much because of sixth gear. there are people that have larger cams getting excellent mileage.

 

But always remember, that good performance takes fuel & air.

 

i lost around 4mpg on the HWY with my 4.11s

i would venture to say gear change= cam swap in terms of gas mileage loss

 

sorry it is a M6

 

On my car (94k miles), 01 Z28 M6 with all bolt ons and a 230/232 FMS F13 cam I get ~24-25 mpg highway and 14-16 mpg city. I don't remember what my mileage was before the cam, but I know my car has lost about 2-3 mpg since it was stock (some of that may be the mods, and some may be its age/mileage).

 

what about a heavier foot since it goes faster?

 

I have a G5X3 cam in my Z06, and with a very rich condition in the low RPM's, I was able to get 27mpg's on my 450 miles trip from upstate SC to western Tennessee.

 

In my M6 TA, i have a 228/232 cam... If i drive conservatevly city i get anywhere from 14-16. Highway in 6th gear i still got 26...

Hope this helps

 

i used to get as much as 25 mixed driving w A4 and LTs. now with a stall gears and cam i could imagine i have cut that down by at least 5-10. i think a lot has to do with how you drive it.

 

im running the torquer 2 (232 234), 4:11s and heavy 17s but getting about 21-22 mpg on the highway and about 16-17 in the city b/c theres a friggin stoplight every 1/32nd of a mile...lol but gas mileage really didnt change much after the cam swap

 

11:1 compression, custom cam, M6, stock 3.42's, 243 heads 28 mpg highway at 70mph (better than stock 25ish). Seemed like mileage improved with the new flow matched injectors, also idles smoother. I do my own tuning with hptuners and a wideband (olsd), I can probably get 29-30mpg out of it as I just got it running 3 weeks ago. Averaging 18mpg city/highway while running it through the gears atleast 10 times and a 0-150 run.

 

thanks guys for the info!!!!

 

How did you get 11:1 Compression Ratio? What is stock again?

 

Stock compression is 10.2:1. I milled a set of 243 heads (stock 64.5 cc's) to 62 cc's and used GM MLS gasket .052". Stock 241 and 853 heads are 67cc's.

 

I got about 300mpg's to a full tank with just intake/headers and exhaust with my M6 with 3.42's...

now after my MS3 went in and dyno tuned with 41lb injectors, I get about 240mpg's to a full tank...it doesnt help having the 3.42's driving around 2-2300k opposed to before my cam I was around 1500rpms in cruising speeds.

 

I want to get my DCR upto 8.5>8.7.. Right now i am at 8.2

I was planning on going ported LS6 heads with a .040" head gasket.

By changing JUST THE cam, you do no change static compression do you? You change compression when you change the heads or head gaskets right?

 

Static compression ratio is physical compression ratio determined by piston (dome, flat, dish) deck height, gasket thickness, and cylinder head volume. (Total volume + cylinder head volume) / cylinder head volume = static compression ratio. Dynamic compression is determined by your intake valve closing point from your cam timing events. DCR is not a set and stone thing just kind of a handy tool to play with. Just shoot for around 11:1 static compression and you will be fine. I am right at 9:1 DCR and people say thats not possible on pump gas (92 octane here). I have no issues even with 27 degrees of timing at wot.

BTW its cheaper to get your heads milled for $50 and buy a set of $28 (Scoggin Dickey) GM MLS .052" than it is to buy those exspensive cometic gaskets.