[Z06] Unusual question - MPG for h/c/i LS7
12-19-2016, 09:02 PM
#21
Safety Car
12-19-2016, 09:13 PM
#22
Burning Brakes
Its all in the cam. Can be a 2-3mpg hit or a 8-10mph hit.
Fuel system has zero to do with mileage. My car with triple 465s and 140lb injectors get stock mileage, because it still takes same amount of fuel to idle at 650rpm and put around at 900rpm as before, and same stoich ratio.
Big cams need idle bumped up. They need to run richer at lower rpm. They need to be kept at higher cruising rpm to avoid surge/issues. This is what kills mileage. If you pick a very low overlap cam, the changes will be minimal.
Fuel system has zero to do with mileage. My car with triple 465s and 140lb injectors get stock mileage, because it still takes same amount of fuel to idle at 650rpm and put around at 900rpm as before, and same stoich ratio.
Big cams need idle bumped up. They need to run richer at lower rpm. They need to be kept at higher cruising rpm to avoid surge/issues. This is what kills mileage. If you pick a very low overlap cam, the changes will be minimal.
12-19-2016, 09:15 PM
#24
Team Owner
12-19-2016, 09:27 PM
#26
Burning Brakes
12-19-2016, 10:02 PM
#27
Team Owner
Big cams typically need to be tuned in open loop to do driveability. If you have a 25+ degree overlap cam it is very common.
12-19-2016, 11:38 PM
#28
Safety Car
12-19-2016, 11:46 PM
#29
Burning Brakes
I have a ton of overlap with closed loop. Obviously has some hesitation but much of its to be expected. I know people used to do open loop back in the ls1 days. I just haven't heard of someone running open loop on a C6Z.
01-15-2017, 09:54 AM
#30
Racer
LS7 4.130
LS7R cam
E85
12.8:1
32mpg in 6th at 80
26-28ish in 5th @ 60
Really shocked at the HP gains and MPG.
LS7R cam
E85
12.8:1
32mpg in 6th at 80
26-28ish in 5th @ 60
Really shocked at the HP gains and MPG.
Last edited by instg8er; 01-15-2017 at 09:55 AM.
01-15-2017, 04:35 PM
#31
Race Director
E85 has 23% less energy in it than the normal E10, so that means you would be getting over 40 MPG on 91-93 octane E10 (normal gas). Do you think that is realistic? How did you measure the mileage? DIC reading is not accurate.
01-15-2017, 05:29 PM
#32
Safety Car
14.5 with steep hilly freeway driving and some highway stop n go