quote:

Originally posted by wideopen231:
question for guys with roots style blower.

Are you running a street or race blower? Race being ones the nylon and Teflon stripping and street having no stripping.

8.71 hi helix/retro stripped. I re-strip it every other year.


Dave

Ok now that paramedics revived me. Every other year? Either they have gotten a LOT better or the low OD does not wear them like the old 14-71 hi helix we ran. Hell every other run was more the norm for a while.
Have you ever checked suction to see when it drops off? I figure et or mph is your indicator.We always checked suction at idle(same rpm every time and never changed idle screws) and 1" difference was 6.0-- to a 6.15-- just example. but it made big difference and I could almost dial the car by it.

I keep track of boost, then watch ET, mph.

ET stays pretty darn consistent year to year to be honest. Boost is consistent depending on overdrive.
I was turning it 5%, then went to 7% and did not gain anything. Thinking my heads are the restriction.

Now if I could just keep a set of lifters in it I would be happy..

Dave

Like Steve I wanted a blower my whole racing career, now that I’ve had one would never go back. Ran an 8/71 for a couple seasons, I could slow it way down with a pulley change and run 6.80’s (4.40’s) and drive it to and from the lanes and it would repeat like crazy. I found it varied less with DA than my injected combo did. Put a couple hundred passes on it between freshens, shift at 7600 finish at 7700 and found my parts artesian was no worse than my 7.20 injected combo, plus when a T/D race was close or I wanted to wow the crowds at my local track I would spin it faster and run 6.50’s @ 204mph. As T/D got quicker I moved up to 14/71 and with the increased fuel consumption I don’t drive to and from the lanes but still really enjoy it, and if I went away from T/D I would put a 8/71 back on and let it eat.

As far as the question on blower, it’s a race prepped with the 3 strips per lobe. 4 season and not freshened yet. Like how it spins faster when looser (vs when restripped) and my boost has not changed the last couple seasons. Found as the rotors broke in the first season after fresh it dropped some boost then settled in, now it’s been the same last couple seasons. I could get that little bit back by freshening it but then it would very again (harder to dial) and I can always spin it faster if I need to, but as long as I’m qualified mid pack see no reason to do that. Monitor my boost with data logger, so if I see another big drop off or it starts verging run to run will get it in for freshen. Do pull it apart every season and make sure the parts inside are happy.

quote:

Originally posted by 3677:
I started a post awhile back rate my combo 477bbc b+m 250 powercharger 12psi flat top pistons 643 roller cam patriot freedom 320 heads rons flying toilit on top home made injecter plate I love this combo been running it for awhile now pushes my undercover car at 1925lbs to 4:80s easy I believe Foley just runner up at one of the SFG races running small blower combo secret is out these combo make consistent power and reliable

I was considering doing a 582 that has somewhat decent compression (around 14-1 probably) and a relatively normal bracket cam for a 582, not small but not super large. Then was thinking a set of Dart Pro2's with the bigger intake valve installed and then putting a TBS 250 street blower on, keep it around 4-5 psi and thinking it'd probably run pretty good. Then have the ability to turn it up with a pulley swap. But the thing with bracket racing that some guys I have talked to, is that with a blower they essentially "create their own atmosphere" so consistency is actually better throughout an entire day as well as day to day etc. That's one of the main reasons I was thinking about doing it.