I am not sure if my MPG is correct for my setup...some say yes some say no.

I currently get 9-10mpg on e85 with 80% highway driving at 60-65 mph (12.5-13 on 93oct)

Forged 364 (9.1:1 compression)
L92 heads
L76 intake
Blower cam (Dur @ .050 232 int 240 exh Lift .595 int .608 exh Lobe Sep 115.0)
F1A Procharger with 3.55 pulley making 16psi)
96lb @4bar injectors
twin walbro 255s with BAP
4L80e
3600 stall (mpg was the same with stock 80e stall)


If my MPG seems correct would swapping out the L92's for 243 heads help?
(bump in compression ratio and better intake port velocity)

I am also experiencing a low rpm/low load missfire that I am pretty sure I can relate to the big intake ports/big cam

thanks in advance

 

yeah im not getting much for mpg with e85,filled mine up today and only got 8.37mpg if i would stay out of the throttle im sure it would be a bit better the best i got so far was 11.3mpg city driving

 

ERic

Im seeing around 11-12 mpg on the e85 but I do hit boost here and there and you can just watch the needle drop and never recover. I cant tighten up the tune a bit and not run 18 psi in my drag radials all the time would help too. Id think if you floored it less you could pick up a few mpg yourself LOL

 

Oh man, not looking forward to this part, lol.

 

auto+blower+e85= unresolvable bad gas mileage.

 

yea...having 700+ rwhp makes it hard to just cruise.

I just wanted to compare and make sure it was right.


P.S.....im not digging the "Mad Dog" add below my post with his bad rep but what are you gonna do...

 

From what I have seen with our cam I would not attribute the low rpm/low load misfire to the camshaft. Are the L92 heads stock, I don't see them being a problem either. Your compression ratio is low, your could stand a healthy bump in compression for running e85. This would really help out your fuel mileage. Bob

 

My previous engine( before a wrist pin committed suicide ) was exactly the same as this one except 10.5:1 compression ratio and my fuel mileage was exactly the same.

 

You could start playing with your timing in your cruising RPM ranges. As Bob suggested, you would benefit from more compression running E85 in both mileage and overall power. I know your experience told you differently, but it's not magic, it's physics. That's why diesels get the best mpg because of the high compression ratio gets the most out of each power stroke.

Stock cruise timing was designed for 10:1 and E0/E10. Now two factors of lower compression and higher octane fuel have slowed the burn rate during combustion and lowered power output. Getting timing on the hairy edge will get the most out of what you got.

In a perfect world, the best way to do this is with a real-time programmer and a load bearing dyno. That way you could play with the timing at different throttle and RPM ranges and get max power (MBT) figured out across the board. This is the way automakers come up with the base spark map.

In the real world, this will be a trial and error process when done on the street. Assuming you still have knock sensors in place you could bump up your timing a degree at a time until you either get knock or mpg stop improving. JMHO