gas milage and boost
Thread Starter
Joined: Sep 2007
Posts: 4,188
Likes: 293
From: woodbine, md
gas milage and boost while we don't exactly build these things for mileage, I usually don't like a tanker truck having to follow me either, lol
anyway, thought I would share what I got on my cruise to the beach
23.3 MPG
72 chevelle, 6.0, LS 3 heads/intake/92MM TB, LS Procharger (D1SC) transplant kit, cog setup, 4L80E trans, 3.50 9", 28.5 tire
I run a 77/46 pulley, around 12 lbs boost, Holley HP controller
the cam is on the mild side, 225/229 , so I could bring in the converter lock up early, around 45 MPH-I run around 1800 RPM's 55
looking at the data log, I was around 14 AFR's, 40 degs total
so you can kind of have it all, lol
on a down note, I had trans trouble, nursed it back home, suspect a pressure problem-I will put a gauge on it today, acts like extreme stall on startup, after a few feet its ok-I built it so its on me, lol
anyway, thought I would share what I got on my cruise to the beach
23.3 MPG
72 chevelle, 6.0, LS 3 heads/intake/92MM TB, LS Procharger (D1SC) transplant kit, cog setup, 4L80E trans, 3.50 9", 28.5 tire
I run a 77/46 pulley, around 12 lbs boost, Holley HP controller
the cam is on the mild side, 225/229 , so I could bring in the converter lock up early, around 45 MPH-I run around 1800 RPM's 55
looking at the data log, I was around 14 AFR's, 40 degs total
so you can kind of have it all, lol
on a down note, I had trans trouble, nursed it back home, suspect a pressure problem-I will put a gauge on it today, acts like extreme stall on startup, after a few feet its ok-I built it so its on me, lol
OD trans and a lock-up converter will make a huge difference! I had my 5.3/th400/3.27/28" tired 'Stang out the other day and it was using ~27lbs/hr which I think =14.4 mpg...pretty bad imo. My converter is loose though.
My buddies car with a 5.3/pt76/ls6 cam/t56 got very good mpgs out of boost, low mid 20s cruising. My car 383/pt76/ls6 cam/4l80e with a tight 3000 stall gets pretty bad mileage by comparison 14-16mpg. The cam is going to hurt you some too, that's one reason I stuck with the ls6 for better drivability, less tuning and better mpgs.
