2001redSS

I'm just curious what some of you guys with light mods and 4.10s get in your M6 cars. I can only manage to get about 21.5 mpg out of mine on the highway. Now granted I drive fast, but I used to get 26 mpg in my '01 SS A4. I'm pretty sure it's running rich since it puffs black smoke on WOT and my bumper has soot on it, but would just running rich kill my mileage THAT much? Thanks.

ramairetransam

iTrader: (18)

thats probably gonna be a tough one to get answers, most who have 4.10s usually have a cam and some mods done that automatically drop the mpgs .

ZHAWK154

iTrader: (1)

enjoy your 20 plus man. cammed m6 and 4.10s in nine inch .... 11 mpg no matter how i drive!

Starz T/A 17

iTrader: (6)

I would say running rich is hurting you a little bit but not that much. I used to get 25 in my M6 4'10 LT1, so you could probable bring it up a little bit, but I wouldn't expect 30 like a stock M6.

Also how fast do you drive? with 4'10's if you go fast enough you are going to pretty much cancel out the overdrive with the increase in gears.

2001redSS

@ramairetransam
I'd be happy to hear from some guys with cams. If they are getting as good as or better mileage than I am, that would still tell me something is wrong.

@Starz T/A 17
Recently it was interstate and I was driving 80-90. I know that kills it too. I'd be happy with 25ish. I was really surprised when I bought this car at how shitty the gas mileage was after what I got in my SS. I wish it still had the stock gears in it.

Starz T/A 17

iTrader: (6)

Whats the speedlimit 70? 75? I would try doing around 70-75 and seeing if that helps. but my guess is that its a result of the car not being tuned and the high speeds. With my DD I can see a few MPG gain/loss difference between 65-70mpg and 80mpg.

I would also recommend getting the car tuned unless your planning more major mods soon.

Rare96LT1Formula

iTrader: (32)

21.5 MPG in an LS1/M6 sounds pretty damn good to me. Although I'd definitely look into the fuel issue. As stated earlier though, many guys on this board with M6/4.10's are going to be H/C/I and tuned. Just food for thought. Your MPG sounds pretty good to me.

BigBirdLS1

I don't know if you have corrected your speedo or not for the 4.10s. If you haven't you are showing more miles driven than you are actually traveling. I assume you are doing math w/ how many miles driven and how many gallons of gas you use. That will skew you numbers some. I have 3.90 gears in my car and the odometer would show 1.1 mile for every mile actually driven. That difference adds up quick.

BigBirdLS1

BTW I got 24mpg highway 20 city w/ 3.90 gears and boltons. With tune and cam I get 19 no matter what.

Hartje

iTrader: (1)

I was getting about 25 on the highway with my 3.42's. I never used 6th gear on the interstate though because my exhaust drone drove me crazy at 1800 rpm in 6th at 65-75.
Also my bearings were beyond shot, not sure if that little bit of resistance hurt my mpg.

Now I get about 26 mpg with my 4.10's (tuned cpu for new gears) in 6th at about 1900-2100 rpm or 65-75mph. (opposite )

All my mods are in my sig I switched to 4.10's less than 800 miles ago... no other mod since

Rare96LT1Formula

iTrader: (32)

Those are some impressive stats. I'd imagine these results would all depend on the tuning. That true?

blt91RS

iTrader: (3)

I'm getting 13-16 mpg around town just bolt-ons and 4.10s..Could really use a tune.

nissan 570sx

I'm quite a bit lighter than an F-body and I get a hair over 20mpg with 4.08 and M6. That's mostly rural/country roads.

fccs

iTrader: (26)

m6 w/4.10s is going to get more then a a4 thats for sure. Mods in sig tuned N/A I get around 15-17mpg city and I would say a around 24-26mpg highway. Your tune has alot to do with it that's for sure. I was once running WOT around 14-14.5 A/F which is pretty lean.., but I was getting around 18-20mpg city and almost 30 on highway then. After tuned right it dropped obviously lol

flintwrench69

iTrader: (11)

Right now I am getting around 25 with 3.73s. I will let you know next month after I install the 4.10s.

DukesOfHazard

With the mods in my sig I can barely get 17 city only. I do drive rather aggressively and my trip is only 3-5 minutes away from work so the car can't properly warm up. I think the car had more mods before I bought it though and was tuned for it.

ttranssam

iTrader: (10)

if i drove very nice on the highway i was able to get around 25, maybe more if i was driving long distance and that was with heads and cam lol but city...hmmm with driving like it was a hotrod (not an idiot!) just crusing id say around 14-17 max

noah89

19/24 with mods in sig. Though, I could go much lower when goofing around.

BriancWS6

iTrader: (18)

With heads/cam and 4.10s running 75-80 most of the time, in less than ideal conditions (hills/mountains) my car knocked off just under 25mpg. I had to down right ABUSE it to get under 20, I only got under 20 ONCE in years and years, and it was 19.xx then.

Anyone with a reasonable setup that's not getting 20+ needs to get a better tune, and check things over.

fccs

iTrader: (26)

Don't forget, if your getting high mpg you should also check what your A/F is while driving. I could set mine to super lean and get 30mpg if I wanted to lol