NitoV

I have 3.42s and I shift up to 6th at 50. She doesn't lug at all.

02chickenhawk

I like having 3.73 gears for the mods installedon my car. When I am cruising 81 mph, the tach is around 2050 rpm....which is almost lugging the motor. 85-90 mph is perfect. I am getting 25-27 mpg on the highway. I don't even calculate mpg in town due to my driving habbits.

Best mod so far to improve fuel economy is my right foot and driving like a highway patrol officer is following me.

01 CamaroSS SLP

You think your almost lugging your engine at 2050 rpm???

S8ER95Z

iTrader: (3)

I use 6th gear with cruise set at 900rpm frequently... lol

adamantium

iTrader: (3)

Lean part throttle can lead to greater gas mileage. Anyone can chime in on there E85 Gas mileage? i know a friend/tuner who claims to be getting 28-30mpg average on E85.

juSStin4171

iTrader: (2)

I put E85 in my truck (09 Silvy 5.3 6 speed auto) once and only got about 15 mpg vs. around 17.8 avg with 91 octane. It actually cost me about .07 more per gallon.

Is it ok to put E85 in a stock LS1?

02chickenhawk

No, I should have elaborated a little. Sorry.

I should have said it is less efficient...might be a better term. My camshaft is 231/230 .644/.605. The car has plenty at low rpm, but feels a lot better >2200 rpm. My car idle is set to a little over 1000 rpm.

adamantium

iTrader: (3)

Did you tune for E85? Atleast the cruising AFR's?

E85 will work great on anything you just have to tune for it.

There are tons of benefits about using E85 over 91 even 93. It has a higher octane, drastically lowers your IAT, and it's alot cheaper per gallon.

The problem is people usually tune E85 car's like a pump gas car (14.7-15 afr cruising) part throttle wise, which is a nono since E85 is alot more knock resistant, you are able to run a more radical cruising afr (16-17.9). That's if you WANT optimal gas mileage while your on e85.

juSStin4171

iTrader: (2)

No tuning as the truck came "E85 compatible" from GM.

adamantium

iTrader: (3)

I'd suggest you tune it for E85 with a tuner. I highly doubt GM's factory tune is anywhere near optimal for E85 efficiency.

SPRAYED 01

iTrader: (22)

I would love to get a stock m6 car, preferably a vette. Put a 273 gear in it, bump the compression by milling heads,full bolt ons, up the tire pressure and seal all the front end gaps and see what she would do at 65mph highway. I dont think it would lug at all. I used to cruise at 50mph in 6th all the time. I would imagine 65mph with 273 would be about the same.

ocshaman

Sprayed, add thinner low rolling resistance tires, and we are on the same page. Can 15`s or 16's fit on a C5?

S8ER95Z

iTrader: (3)

Not on the front.. 17s or specialty 16s (I think I've heard that mentioned but can't think of what they were bogarts?). The front brakes are too large for 16s or less.

ocshaman

Can't win them all. Downgrading the brakes to F-body or similar would be sacrilegious wouldn't it?

Zebisko

iTrader: (3)

Just as a little bit of information, when I did my head gaskets and cam swap on my lt1, I ended up putting impala head gaskets on, which I am led to believe raise compression to right around 11:1(unsure of that, however). With an untuned lt4 cam in it, it still returns the same mixed/highway fuel mileage it always has, which is usually around 24mpg. Food for thought.

S8ER95Z

iTrader: (3)

On the lt1 you may have gained a couple of points of compression but 11:1? I was 10.7:1 with decked heads and thin gaskets on my old CC306 setup.

ocshaman

https://ls1tech.com/forums/lt1-lt4-m...thickness.html

S8ER95Z

iTrader: (3)

Wow I must have been way over 11:1. :/. Thanks for the info.

ocshaman

No worries, I just typed head gasket impala compression ratio lt1 into google.

S8ER95Z

iTrader: (3)

All good my car was long gone before that conversion ever took place. Lol I probably just had bad information back then. Was 2001ish when I had thy setup.