Gas Mileage and V8's

[89StangGuy]

Hey everyone, I own a 89 Mustang 5.0, and i was wondering what kind of gas mileage other 5.0's are getting? Doesnt have to be a Stang, just any car with an 8 cylinder. Im averaging on the street about 14mpg and about 22 on the freeway. Im just checking to see if that's normal cause i have a 4cylinder turbo svo and it was putting in about 36 on the freeway, and 28 on the street. Not a stock motor btw, and i was driving like an ass. Any input is appreciated.

[kdracer73]

This is kinda apples to oranges, but throwing it out there. 73 Camaro, 383ci, 4 speed auto trans, carb. I got 12.82 mpg on the last cruise. I can squeeze out 14.82 solid highway cruising.

[89StangGuy]

This is kinda apples to oranges, but throwing it out there. 73 Camaro, 383ci, 4 speed auto trans, carb. I got 12.82 mpg on the last cruise. I can squeeze out 14.82 solid highway cruising.

Whoa, 14.82 highway cruising? Ok i think im just complaining when im getting about that on the street. I have a 306 ci in my 89 Fox with the AOD tranny. Im just trying to compare to see if that's actually the mileage im supposed to be getting or if it's supposed to be more. I haven't driven a v8 in a while so getting less than half the mileage my other car is getting it kinda threw me off.

[94cobra69ss396]

Mike, that sounds about right if you drive with a heavy foot like I do. I did a fuel millage test a while back and the results are in the thread http://www.motorgen.com/forum/showthread.php?t=522. However, just know that in these tests I was very light on the throttle. I don't think I ran the rpms up over 2500 or so during the whole test. I've also checked my mpg a couple times with a combo of city and hwy at my normal driving and if I remember correctly it was somewhere around 18-19mpg.

[94cobra69ss396]

Sorry, I forgot to mention that this is in my 1994 Cobra with a Vortech blown 302, 3.55 gears and a T56 that has a .62 6th. You will also pull better millage with the E303.

[89StangGuy]

Mike, that sounds about right if you drive with a heavy foot like I do. I did a fuel millage test a while back and the results are in the thread http://www.motorgen.com/forum/showthread.php?t=522. However, just know that in these tests I was very light on the throttle. I don't think I ran the rpms up over 2500 or so during the whole test. I've also checked my mpg a couple times with a combo of city and hwy at my normal driving and if I remember correctly it was somewhere around 18-19mpg.

Wow, your Stang gets really good gas mileage for being blown. I bet the story changed as soon as you get on it a few times a day. I always try to do a gas mileage test but i cant keep my foot off the gas, so i can never get a really accurate reading. All i know is i hit like 120 miles and i had 2.2 gallons left, and i have a 12 gallon tank. So im guessing i would have hit around 150. So thats about 12.5 mpg driving with a heavy foot everywhere. Would changing the C shaft this weekend make any difference?

[94cobra69ss396]

Wow, your Stang gets really good gas mileage for being blown. I bet the story changed as soon as you get on it a few times a day. I always try to do a gas mileage test but i cant keep my foot off the gas, so i can never get a really accurate reading. All i know is i hit like 120 miles and i had 2.2 gallons left, and i have a 12 gallon tank. So im guessing i would have hit around 150. So thats about 12.5 mpg driving with a heavy foot everywhere. Would changing the C shaft this weekend make any difference?

Yes, changing to the E303 cam will help. It's the same cam I'm running in the Cobra. Do you know if you have a custom tune?

[89StangGuy]

Oh ok sweet. Better gas mileage would be helpful to my wallet. My car has never been professionally tuned, me and my Uncle pretty much tuned it in his driveway, messed with the tps, and timing and all that. Why whats up?

[94cobra69ss396]

Oh ok sweet. Better gas mileage would be helpful to my wallet. My car has never been professionally tuned, me and my Uncle pretty much tuned it in his driveway, messed with the tps, and timing and all that. Why whats up?

Did the computer already have a tune when you bought the car or is it stock?

[enkeivette]

I've ranged from less than 7 in the city, to mid twenties on the freeway. Depends on the driving, the tune and the gear. It's hard to suck a lot of gas in 6th gear.

[89StangGuy]

Ron - It's the stock computer, It didn't have a tune before. When i got the car it was completely stock, original everything. I changed out the motor when i found out there was about 13 inches of cracks along the side of the block. But besides that, all the electronics are stock.

[89StangGuy]

I've ranged from less than 7 in the city, to mid twenties on the freeway. Depends on the driving, the tune and the gear. It's hard to suck a lot of gas in 6th gear.

Dam, ya it does look like I'm just complianing ha. I have stock gears, stock tranny, but i drive the car hard as i just got the motor in last month and its already broken in. My car is untuned though, i slapped the motor in and messed with the throttle position sensor, advanced the timing and just kept it like that. Im planning on getting a tune after Ron and I put in my new camshaft. Don't know where to get a good one though.

[SeanPlunk]

The Cobra gets about 14mpg. That's pretty much all city though with a slightly heavy foot.

During mixed driving I was getting closer to 17 or 18 and on just open highway I can get 23+.

[94cobra69ss396]

Ron - It's the stock computer, It didn't have a tune before. When i got the car it was completely stock, original everything. I changed out the motor when i found out there was about 13 inches of cracks along the side of the block. But besides that, all the electronics are stock.

Perfect, as long as you have the correct MAF for your injectors. Depending on the heads you have you may not even need a tune. If you do need a tune Steve at Powertrain Dynamics is the guy to go to. He tuned my car both times I've had it tuned. The first time it put down 433rwhp. Then I installed a UPR intake tube and it put down 471rwhp. That's with 70,000 miles on the engine.

Once we get the cam installed you should run it on a chassis dyno just to make sure that the AFR is good. GTR High Performace has a dyno and I think they charge around $75 for three pulls.

What are you running the base timing at now?

[89StangGuy]

So I'm guessing Steve knows what he's doing? Ha I dont remember the exact specs on the heads but i know they are cast iron, and that the ports are almost exactly similair to the AFR 185's but they are said to flow better, they're powerhouse heads i think. The timing is advanced right now 15 degrees, any lower it runs lean and shuts off, any higher it runs too rich and idles all retarded. Im cool with getting it dyno'd too I'm bringing extra cash with me in case we need anything else. Where is the GTR located?

[94cobra69ss396]

So I'm guessing Steve knows what he's doing? Ha I dont remember the exact specs on the heads but i know they are cast iron, and that the ports are almost exactly similair to the AFR 185's but they are said to flow better, they're powerhouse heads i think. The timing is advanced right now 15 degrees, any lower it runs lean and shuts off, any higher it runs too rich and idles all retarded. Im cool with getting it dyno'd too I'm bringing extra cash with me in case we need anything else. Where is the GTR located?

They're located out here in Rancho Cucamonga but you'll have to schedule an appointment with them. If you want to schedule one with them let me know and I'll see if I can get you a deal.

[89StangGuy]

Sweet i'll let you know. Thanks again Ron, See you this weekend.

[Sonic03SVT]

had a 94 5.0 and before the H/C/I it was doing 16/24ish?

after that? less. :P

[SeanPlunk]

had a 94 5.0 and before the H/C/I it was doing 16/24ish?

after that? less. :P

What do you get in your stock pulley Cobra?