8-71 blower questions for guys with experience please!!
Thread Starter
Junior Member
Joined: Jan 2010
Posts: 37
Likes: 0
Car: '91 Firebird
Engine: 468 BBC w/ 8-71 blower
Transmission: Th400
Axle/Gears: 9-bolt 2.77
8-71 blower questions for guys with experience please!!
I bought a 468 BBC with an 8-71 blower, currently running 90/110 octane 50/50 mix for 100oct. The blower is currently running 15% underdriven, 9.0:1 pistons.
My main question is could I drop to 20% underdriven and run regular 91 pump gas on the street? Other than a decrease in power would this have any ill effects on my set up? From the charts I have seen from Weiand at 20% underdriven an 8-71 is putting out about 5 pounds of boost, and with 9.0:1 pistons I'd be between 11.0:1 and 12.0:1 effective compression. This engine was dynoed at 980hp 980tq running 15% over driven so I have plenty of power to play with here when I take it to the strip, but since this is going into a fun summer driver/show car I'd like to tame the beast and make it a little more drivable, and lastly running that low of boost, is it ok to stick with my power brakes? Thanks in advance!
My main question is could I drop to 20% underdriven and run regular 91 pump gas on the street? Other than a decrease in power would this have any ill effects on my set up? From the charts I have seen from Weiand at 20% underdriven an 8-71 is putting out about 5 pounds of boost, and with 9.0:1 pistons I'd be between 11.0:1 and 12.0:1 effective compression. This engine was dynoed at 980hp 980tq running 15% over driven so I have plenty of power to play with here when I take it to the strip, but since this is going into a fun summer driver/show car I'd like to tame the beast and make it a little more drivable, and lastly running that low of boost, is it ok to stick with my power brakes? Thanks in advance!



