i was wondering if really modded sevens still got about the same gas milage as stock ones. the reason im asking is because the turbo sevens get almost the same mpg as N/A.

 

Actually with the correct mods you will get better than stock gas mileage, however 99.9% of the drivers will use that extra HP and suck the mileage back down.

 

14 city, 22-24 fwy.
400+ whp

 

nice

 

12* positive split from max vacuum to about 16-18", then about an 8* negative split with about 45ish degrees overall advance. afr's in the low 15's.

it'll actually fire the mix well into the 16's, but running that lean takes so much power away that you need a higher throttle position, and hence-less vacuum, so it's less efficient with the current motor.

next motor has ports that open later (not the best thing for power at low boost levels), a cosmo inermediate (primaries open later than fd's), so it's got less overlap overall. i'm hoping that will let me run the mix into the high 15's and stay efficient. can't say until it's all said and done, but i'm hoping for 25+ mpg consistantly after it's all re-tuned with the new motor. and yes, it'll still be above 400 whp

 

 

Just because it is a turbo car doesn't mean you have to use the turbos. Riding down the interstate you are going to be under vaccum anyway. The only difference is the turbo car will probably have a little more exhaust restriction due to the turbo manifold, which will rob alittle mpg but probably not enough to be noticable.

 

the engine compression being lower in the turbo cars will have more of an effect than the manifold.

 

i get 17 city 24 highway. i think i can do a bit better though.
because thats still going to redline every now and then.