PhillyLS1

iTrader: (3)

What should my F1A be boosting at w/ the 3.90. I am getting inconsistent boost. In 4th gear I am only boosting 5-7psi. Needless to say I'm starting to get pissed off.

Don't get me wrong, the car is a BEAST, but this is getting silly. I also understand weather effects boost a lil, but I should be pushing at least 10 more psi... right?

I will post pics of my set-up. I think I may be sucking the filter closed? I can't think of what the hell the issue is.

ANY help would be appreciated.

C5kid

iTrader: (12)

belt slip?

Bob@BruteSpeed

iTrader: (16)

My 408 with an F-1A made 19 psi of boost. Try a run (clean road...) with the inlet side off the blower to see what happens to your boost level. Bob

PhillyLS1

iTrader: (3)

No belt problems whatsoever. I have a custom set-up. And there are ZERO signs.
I had the same belt for 2 years.

Bob, do I have the correct pulley?

Also Bob if you don't mind I'm going to post up what I have for a set-up. Let me know what you think.

Ws6kid.

bob is that 408 on a Fbody?
i would like to see your belt set up
i hear alot of bad things about belt slip with such a huge procharger
trying to decide to go TT or F1-r/a

Bob@BruteSpeed

iTrader: (16)

Yes. It was with a the standard 7.65 ProCharger 8 rib crank pulley and a 3.90 pulley on the head unit. At the first LSX Shootout the car did a 9.12 at 146 mph. The car was driving through the Powerglide's torque converter big time. Couldn't even hear the 1-2 shift. We were checking and tightening the blower belt after every run. KP was using the SCDE tensioner on his T/A, he didn't have any belt slippage problems with his blower belt at all that I know of. Bob

Ws6kid.

Thanks for the info, been looking into the F1-R/A or the modular twin turbo kit
looking for 800ish+ rwhp. also want to run a single digit at the track but with a full interior car....

PhillyLS1

iTrader: (3)

Pics of the set-up:

ttranssam

iTrader: (10)

dude....lol clean them wires...

PhillyLS1

iTrader: (3)

soon as i get all this **** figured out

speedracer5532

iTrader: (8)

Keith, there is no way you have trapped almost 140 mph in the 1/4 on only 5-7 psi of boost. I would first check your boost gauge. I am sure your getting way more than 5-7 psi.

PhillyLS1

iTrader: (3)

LOL Wanna see the slip? The logs indicate the same thing.

The MOST I've seen is 11psi in 3rd gear, which goes along with the logs and performance of the car. Why would I get a higher boost reading in 3rd rather than 4th?
When the gauge says 11psi, the logs say 11psi. When the gauge says 5psi etc etc.
I also had this gauge when there was a turbocharger on the car and it was dead accurate.

I wouldn't have spent money on fabrication over a $150 gauge. Nor would I make this thread.

I have no indication of belt slippage and yet inconsistent boost. I'm at a loss just like you are.
The only thing I can think of is the gear I'm in and the RPM of the supercharger? I dunno. I've been looking for answers on the web all day.

EDIT: Also I've hit higher boost levels before the engine build, but I've had this issue since day one. Any theories are welcome.

speedracer5532

iTrader: (8)

I have got the most boost with an auto tensioner setup but I have also broke the most belts with the auto tensioner setup also. I made a much better manual tensioner pulley holder so I could really crank the belt super tight and keep the pulley from wanting to caulk towards the bracket from too much tension on it. I haven't broke any belts running with a manual tensioner but it is harder to get the boost with a manual tensioner.

TransAmatt99

iTrader: (24)

What does it do if you pull your airfilter off and run it open? I gain two psi just by pulling the lid. Your airfilter looks dirty too, try it both ways and see if it makes any difference. As for my theory it seems it would have to be either belt slip or that bypass valve you have on there isnt closing all the way and letting air escape. But with an F1 you should be getting a ton of boost, I see 14lb with my V1SI on a 403. Good luck.

PhillyLS1

iTrader: (3)

I haven't had the time to put it on a dyno and see if this works. I'm gun-shy about running the blower filter-less. The filter that you see there came with the kit provided by EPP.

Dirt may be an issue, but do you think the filter may be getting sucked closed?

9sectruck

iTrader: (9)

im sure you have the crank pined? the filter does look like it may be collapsing, my f1 would suck my filter shut I would see 21psi of boost then bomb it would just drop to 0 instantly by the 6-7th run it chuck the gears out of the blower, $3700 repair
try pulling the filter itself off the inlet tube, that very well could be the problem

PhillyLS1

iTrader: (3)

Yep, crank is pinned with both pins. Ok, gonna pull the filter like you guys said. Dyno time I guess.

AFASTYZFR1

iTrader: (55)

The filter appears to be getting sucked in. I would pull filter and see how it does. The inlet pipe doesn't appear to be restrictive.

J_Croatia

Original filter you purchased with kit? Dunno if this makes sense but, it may have lost its rigidity over time and is now being sucked shut.

Bad30th

iTrader: (13)

If you're nervous about running with no filter, try putting some pantyhose or screen over the charge pipe.

A blown 408 needs a lot of air - I may be wrong but that filter doesn't look like it's up to the task... Definately worth checking. Not sure it would cause the variation in boost you're seeing though. ...maybe an intermittent boost leak somewhere ?

Rob (Bad30th)