zapp168

iTrader: (7)

Boost just levels off at 5500 RPM.... no belt slippage, I smoked all the piping to look for leaks....none, and I removed the inlet "hat" no difference. Does that mean the D1 just has no more to give? Specs in sig

9sectruck

iTrader: (9)

My f1 does the same thing, procharger told me that the inlet impeller is making its own turbulence; they said the way to fix is put a velocity bell on the inlet of the charger

DeltaT

iTrader: (5)

The first thing I always suspect is slippage. The fine rubber dust indicating slippage might be getting blown away by the time you hit speeds enough for your boost to go flat.
If your belt is not tight enough to 'twang' like a guitar string when you pluck the longest side of it, it ain't tight enough. Look for dust caught in the cracks farther back on the motor and brackets.

Or possibly your FMIC is restrictive. What is the max rpm you are spinning the D1 to? That's a pretty big motor to feed.

Jim

EPP

iTrader: (22)

How much boost are you seeing? Bob

zapp168

iTrader: (7)

Well I got the tensioner set up that was supposed to eliminate slippage. I have little need to go to 6000 RPMs, I think the limiter is set at 6500. I guess I could by-pass the intercooler and try that, it is pretty well plumbed in though now.

zapp168

iTrader: (7)

About 10 PSI, RPM climbs but boost does not.

ZLEEPER

iTrader: (24)

I would agree on either belt slip or intercooler restriction. I was seeing almost 7 lbs difference from intercooler to intake at one point.

ChevyChad

iTrader: (50)

Gotta be belt slip.

BLOWNBLUEZ06

iTrader: (17)

Often times the belt will slip on the balancer too. Cartek is making a "flip drive" for the Corvettes and they seem to eliminate belt slip. There's a car that they're playing with that's running 21psi on a D1 and a 347, making 730rwhp through an auto and with a 6-rib belt.

https://ls1tech.com/forums/forced-in...nds-boost.html

ChevyChad

iTrader: (50)

While its great for vettes, the flipdrive is completely meaningless tho to the OP here since he is working with a 4th gen fbody..

If tightening the snot out of the belt doesnt help, you may want to look into the SDCE setup. It has a spring loaded tensioner that pretty much eliminates belt slip for the fbodies.

LS1RedZ

iTrader: (19)

You ought to be seeing alot more boost than that I would think. Contact Aster on here if you are looking for a nice bracket that will eliminate belt slip. I just put one of his brackets on my car.

Slowhawk

iTrader: (12)

I hit 14-15lbs on your car with the inlet off. Oop's forgot to tell you that...LOL

Tighten the belt -alot.

vette_c6

if your engine is 6.8
and your stroke 4
means your piston is 4.1
means you are 418 cid
if i am right


max out your supercharger for D1 with pulley 3.2
on 6500 RPM will give u 62460 rpm for supercharge

on 6200 RPm it will give u 6000 RPM for your supercharger
asuming that your crank pulley is 7.5
and you are using D1SC

if you are using D1
you can use pulley size 3.2
and it will give u 64000 RPm(supercharger) on 6200 RPM engine
your maxout will be on 65000 rpm for the supercharger

you will expect boost on what i said MAX out ur superchager
D1 will be 12 PSI
this is true if :
your crank pulley is 7.5
your step up ratio is 4.4 ( D1 ) ) correct me if i am wrong guys
your max blower speed is 65000
your blower cfm is 1400
your engine is 418
----------------------------------------
D1SC same stuff
but your step up ratio is 4.1 and your max blower speed is 62000
you will get 11.5 boost

i hope this will be your answer

zapp168

iTrader: (7)

I got the SDCE tensioner system because I was "convinced" that all my problems was from belt slippage (of course they did not care to hear that there was no difference after the sale, and install). So my understanding is that this system "eliminates" belt slippage. So I took off the hat and went for a drive I did not see a difference, I will admit that was in town and things do get a little hairy past 4000 RPM's but 5# I figured I would notice. I am not too concerned, as the car is not slow, and I thank all the responces. I have put like 500 miles on it since the dyno run in like.... June? We relocated the intercooler and the car runs nice and cool now.

Vette C6 most impressive logic, and makes alot of sence, except for SLOWHAWK saying he got 14-15 PSI with my car on the dyno with the hat off. I was not aware of that. The boost phantom must be stealing my boost

Slowhawk

iTrader: (12)

Didn't want to scare you with no filterHad to make sure the tune was spot on too "when" you redid the intercooler/inlet.

FYI- Our 427ci Vette ran a consistant 14-15lbs of boost with the same pulley combo -for 3 years.As for belt slip,we run the stock pulley setup with a F1 blower car pushing 19lbs without belt slip.

zapp168

iTrader: (7)

I wish that you had scared me, the dick from SDCE convinced me that the hat made no difference and it was 100 % belt slippage. So I bought his pulley setup which did nothing, and the fan setup which fit after two hours of modifying it. I just moved the intercooler forward, since I did not really need to move the radiator........right??? Which BTW I believe was the reason it was running hot the whole time, my fan set up with that radiator was more than adequate.
So now I am faced with taking it all apart again and re-doing the front end all over . Not to mention that I got the injectors re-sized to 73# and just plugging in the numbers from the spread sheet that I have always used messes up the AFR alot.....Re-tuning the VE on the street has almost got me killed, it is breaking up in high RPMS, and I just don't care Next step is the for sale sign at this point........
So had I known before that the hat had been removed and you saw 14-15 LB for sure I would have just ignored SD talking about my choice of tuner and cut a little deeper. Either way I am out a grand, have to do hours of fab work over, and I can't even really get on my car without fixing whatever issue I am having with the IFR table. I have no time to do any of this, and I wish I just left it alone! I am kinda discouraged if you didn't notice.

ChevyChad

iTrader: (50)

What size filter are you using? Stock f-body hat?

zapp168

iTrader: (7)

I am using the long K&N filter with a 3 inch connector to the f-body hat, with the aftermarket radiator being so thick it is all that fits without moving the rad forward

ChevyChad

iTrader: (50)

How long? The 9" long one (RE-0920)? I picked up about 1.5psi on my old P1 setup going from the stock filter to the bigger RE-0920 filter with the fbody hat. Also, not sure if its been proven to flow better, but the truck hat fits and looks like it would flow significantly better than the stock fbody hat.. Just throwin out suggestions.