I posted this in the C5 tech section too. I am wondering how much boost a 3.85" pully (ATI) makes with a 224 Cam, Off Road X Pipe, and LT Headers. I have not got my car on a dyno yet and cant really look over at the boost gage once it starts to come on...I have to concentrate on the road, the last I see is the needle swinging up to 4-5 lbs but it is swinging fast so I know it is going past that.
Thanks

 

Don't know the answer to your question, but I'll bet you will find that the results are very inconsistent between cars. There are just way too many variables with the D1s on non stock setups.

I got 9psi on mine with a 4.25, but I need to get more fuel pump behind it before I can verify. I've seen others only getting 8 with the 3.85.

Try to find a dyno that can log boost in the software, or take a video camera.

I know exactly what you are saying about keeping you eye on the gauge. I’m not even driving mine much until I get the fuel pump issue resolved. At first I thought I could just keep the boost down to around 5, but then I realized that all hell breaks loose when just about any boost starts to read. It’s a good problem to have. :cheers:




[Modified by QuickSilver2002, 6:36 AM 10/20/2002]

 

Kevin,

Give me a call and we'll just meet up so I can wach the gauge while you drive. Simple solution. Maybe we can get a pull in while we're at it. :reddevil

 

I also have the 3.85 pully with TPIS long tubes and the P1S ATI blower...The car does not have a cam...My #s where 508 rwhp, but i have had some long term programming problems which i hope will be solved this week...I should end up around 525 rwhp, so i would think yours might hit 540? Should be a blast for you :cheers:

 

for one thing that Katech Tensioner won’t work! It does not tighten as you rev the motor like the stock unit. And if you get it tight enough you will mess up other components on the car. The biggest reason all the cars are so different is because that piece of crap blow off valve that comes with the ATI unit. Do you self a favor and Get a blitz or some other after market blow off valve.

 

Please explain the blow-off valve problem. Does it leak? Maybe that would explain my intermittent boost? (I know my belt is not slipping and I have no leaks) Where does one get the better valve?

 

If your boost is not consistent then that may be your problem -- there was a lot of talk a few months ago related to the blow-off valve and how it leaked. I am unsure but it appears that the one I received with my kit is of a better quality than those shipped earlier this year. You might want to do a search of old posts -- if they are not to far back there are some threads that may be enlightening. If memory serves me right ATI did replace some of the members blow-off valves under warranty. Summitt Racing carries blow-off valves among others. Sorry I could not be more help.


[Modified by Mad_Dog, 1:11 PM 10/22/2002]

 

I appreciate the responses. I went ahead with the Katech tensioner a number of people are using them on higher boosted cars and appears that they work...at least I hope.. I and many others have found the problem to be with the stock tensioner that when you accelerate or are under power the belt tightens via the spring loaded stock tensioner...when the belt shreds it is on deacceleration when the tensioner snaps back into its normal resting place..the belt rib jumps over the inboard idler pully, the idler pully acts like a pizza cutter and cuts the first rib on that belt. Some of the fixes are to mill the bracket and blower housing to move the inboard idler pully closer to the blower, so that the belt rides more center on the idler pully. I am going to try the tensioner to see if it works, it seems as though you may have some belt slippage Cya5, with 9 lbs of boost on a D1 it seems like you should be making over 550 RWHp vs 500. I know stock c5's running P1's with 7lbs of boost making 485 RWHP...I am not calling you a liar, but did you try the tensioner. I know an ARE setup that got rid of the Katech tensioner and went back to a brand new stock tensioner, but I was told by ARE that they were scratching their heads on that one.
Thanks

 

Let me put it this way. If you are having belts hopping off the pulleys. YOUR BELT IS TO LONG! I have a Katech tensioner I will sell for $100 if any one wants it. I can get any one on the forum new Katech Tensioners for $110. But they don’t work properly. If you don’t car about tearing up your other components running off the belt you might get one to work but….. If your car or tensioner has over 15k on it get a new tensioner.

I wonder if all the guys having all these problems have their blower pull on the right way? The blower pulley will not work properly both ways.

I was one of the first to get this set up to work. My car makes 500 RWHP on PUMP GAS with back-to-back dyno runs and it was 98 degrees out side. At the time I had a stock motor with 9lbs of boost. Currently I run the car at 10lbs of boost with a 4.0 pulley on pump gas still with a stock motor. It goes all day long. If you run a smaller pulley than a 4.0 your belt will smoke with a 6-rib setup. I really should get some new dyno pulls on the car but I don’t really care to mess with it. Why should I? I can spin my 295X18s at over 60MPH.

As far as the blow off valve goes I have ATI’s “good valve” it is just as much trash as the “old one”. Take your blow off valve off and try to pressure it up to how much boost you are running and see if it holds. I have a blitz valve and it works very well. If your car runs with the ATI set up that is cool but the blitz valve is hands down better.

P.S. if I put race gas in the car it makes a little more power. I just don’t advertise that. :D

 

I am not smoking the belt. It is true if you don't have the blower pully on the right way it can cause problems. The pully should be placed on the blower so that is it closest to the blower. My tensioner brackets have been relocated to wrap more of the belt around them (approx. 40% more). I don't think I am having any slippage. I still think that your setup should make more RWHP on the dyno running 9lbs...if it is not than everybody elses system is working amazing. I do think that the 8 rib belt is a necessary mod over 9 lbs of boost and if I see any indication of slippage I will buy one (them)...most likely I will get it from Golden West Performance (GWP). I also agree that maybe purchasing brand new factory tensioners every 10-15K miles could be a solution. I used a very short belt on my car, I had to drive the factory belt tensioner all the way to its limit to put the belt on, it kind of looked like it was starting to tweak a little at that limit...so I switched to the manual tensioner, it arrives on Thursday..so I try it and then will explain how it is working. I think it is logical to assume that if using an 8 rib belt system, one would not have to tighten the belt as much as possible as with the 6 rib system. I know your car is stock, but my car is setup real similar to a car that made over 630 RWHP...using a 6 rib belt!
Most likely I am going to go to a bigger pully because I can not hook the way I would like. I will probably put a 4.36" pully on for the street and road course, and then use the 3.85" for the drag strip.

 

Sounds cool! :cheers:

 

Where can I buy the Blitz blow off valve???? Also Cya5 did you try the Katech tensioner???? What happened or did you just opt not to go with it because of potential accessory wear?
Thanks

 

When you put it on you can tighten the holey ____ out of the belt and you might get it to not slip. But if you tighten it correctly! Not so tight you will screw all kinds of stuff up the belt will slip when you get over about 4500 RPM. The spring tensioner however will tighten as you go up in rpm and loosen as you come down keeping an even tension on the accessories. I know it sounds crazy. I had a mustang that had the Vortech manual tensioner on it and thought for sure the manual would work on the vett. Well it doesn’t the belt is just too long and has too much area to stretch under load. The best and I think only way is to go to an 8-Rib setup. The 8-Rib set up will also bring the boos in quicker because the belt wont slip when you hit the gas. Ideal we should have a cog drive but the 8-rib will work for most of us not wanting to go crazy.

One other great thing about the manual tensioner is if you tighten it to tight it will throw an idler pulley through your radiator. Trust me on this one guys manual tensioners suck! But hey if you want go have fun.

Drop me an email and I will find you the part numbers and get you a picture of my blow off valve set up. It‘s sweet.
:cheers:

 

Shinobi'sZ

You probably already know this, but your belt is going to stretch as it breaks in. You might want to see how the stock tensioner looks after the belt stretches a little.

I would not mess with the manual tensioner if you are not having problems with the stock setup.

 

Here's something for you guys with belt slippage problems to keep an eye on.
http://www.ls1tech.com/ubb/ultimateb...;f=20;t=001169
:smash:

 

Anyone using the Billet 1.5" blow off valve? I've been hearing good results from a couple of people........ :yesnod:

 

Kevin , i'm running a 4.25 Pulley and pushing 8 PSI of Boost.
I've only seen my Gauge get that high on the DYNO , the most i've seen on the highway is about 6 PSI .

:cheers:

Jeff

 

Thanks Jeff, I am going to throw my car on the dyno soon. I just want to hook up my fuel pump first.

 

That was my car where we put the factory tensioner back on and NO more slippage...I personally tryed tightening in tight, tighter and super tight, made no difference...Makes no sence to me either... I am running the 3.85 pully now and making 7 1/2 lbs which i consider max for my car...Car is at ARE for programming now, should have back in a few days... :cheers:

 

When everyone talks about pulley size, be sure to clarify what blower you are running. There is a world of difference between a 3.85" pulley on a P1 vs a D1.

On stock Z06's we run a D1 with a 4.375" pulley. That made 570RWHP on an '02 w/ just headers an exhaust. That is about the most a stock fuel system can handle(actually well beyond, 550RWHP is about the max), plus I have to take out a bunch of timing. The 3.85" pulley on a D1 will make about 12psi @ 6000 rpm if everything is set up right.

I would strongly advise against using anything other than a stock tensioner. A solid tensioner is bad for many reasons. Primarily the belt is not designed to absorb the stresses that occur under acceleration. I have heard of people snapping belts with a solid tensioner. That is a minimal problem usually. A worse case is destroying your accessories over time because they exceed the loads they were designed for.


[Modified by Mike Morgan, 8:55 PM 10/23/2002]