Hello everybody !Please ,tell me what minimum size of procharger pulley is working without slipping with 6 rib belt? My pulley is 3.5" and it is making only 7 psi on 5500 !Procharger people dont want to answer.
Ny unit is D1SC ,crank pulley is stock 7"

 

I would go no lower then a 3.40" on that car.

It's all going to depend on how good your tensioner is.
EA

 

3.4 with 6 rib is about max wo slippage.... could even be slipping now without you aware and so lose a bit of boost there so...

gatorback v belt helps in this regard over the gates my opinion

 

you can try to improve belt wrap on the s/c but then the belt will slip on the crank pulley .even if you put on a new belt and better belt wrap it duznt last long the belt will slip and start to glaze .lots of people say they have no belt slip with a six rib but i bet you if they look under the hood they will see belt dust .it takes a bit of power to spin the blower a 6 rib will just slip.all the guys i know with blowers have belt slip with a6 rib belt.its what i think i tryed every thing on mine like even makeing my tensioner lockable and put about 100lbs of pressure and after about five minutes the car lost 4 lbs of boost and their was a lot of belt dust .so i got a guy to build me cog pulleys for my 91 vette .and i was told by procharger that cog pulley are safe on a blower as long as you have a blow off valve /surge valve give hime a call he can build you 8/10/12rib pulleys if you dont want to go cog his prices are very good check him out www.blackmountainprecision.com

 

Smokeshow, could you post pix of your setup. I'm interested in how it looks as well as functions. Thanks in advance...John

 

Eric,
I didn't know you posted on here...I thought you were a Mustang guy! Will you be at PRI this year?
Brand-X
PS-we are now a Mustang household...my wife bought a '03 Codra w/mods.

 

I disagree with a lot of what is posted above. While I do agree that more ribs (8/10/12) and cog drive will reduce if not eliminate belt slip, it is not necessary in all applications.

I too have run the cog drive and they are tough on the head unit (I run twin Vortech race bypass valves). If you talk to the manufacturers (i.e. someone in tech at ATI/Vortech who knows something, or maybe Greg at BW) they will confirm the wear that is placed by the positive drive. Much of the slip issue is due to the blower trans that is used. If you look at the step-up ratio (SUR), you will note that they vary based on model. The SUR on a P600B is 3.05:1 while the SUR on the D1SC is 4.10:1. This means that in order to get the P600B impellor spinning to max impellor speed (MIS), the driven pulley (pulley on the blower head unit must be significantly smaller than one on a D1SC. The smaller the pulley, the greater the belt angularity is, and the more potential for slip.

To get to MIP on a P600B, people typically will have to go to a 2.25" diameter pulley, while a D1SC can get there with a 3.4" diameter driven pulley. The larger 3.4" pulley has less probability of slipping vs the smaller pulley (think along the lines of drag slicks, larger the diameter, the more contact area, thus more traction).

Additionally, there are only a few C4 engines that suffer from belt slip at the crank, with the 93 LT1 probably being the worst. This is purely a function of belt wrap. Look at the belt routing guides for the various engines, and you will note that most have pretty significant drive belt wrap, such that slippage at the drive pulley (crank) is not an issue. If you do have belt slip, the dust is around the driven pulley, not the drive pulley.

Save yourself some money and improve the belt wrap on the driven pulley and also save the wear on your head unit.

As a side note, I have the cog system off of my car and I am back running a factory six rib. I am seeing 14 psi by ~4700, with 18 psi at 5300. I am not running it up to the 6400RPM redline due to still tuning, but I hope to get there maybe by the end of the Thanksgiving weekend. It will be well past 20 psi. This package uses the factory crank pulley, ATI supplied driven pulley (sized for MIP) and factory tensioner (with no helper springs, jackbolt, etc.). It can be done.

Aaron

You may also wish to take a look at the other post on here about "More Boost, Larger SCs".

 

hi,i seen your other post about more boost but you have a d1r that is a killer blower that will send any engine that is not built right into a million pieces.i cant see it having any problem pushing that kind of boost even with some belt slip.how much do you think if you had cog pulleys on it you would get out of it(p.s.i).and when you say cogs was hard on your blower what did it damage?my friend had a vortech(in my opinion no where near as good as a procharger) with cogs and it did kill it but then he went to a d1oil fed procharger and has had it coged for 3 years with no problem and it a 5 speed mustang.i do think a cog pulley is harder on the head unit .on my 6 rib i increased the belt wrap and put on the best belt and it made good boost but i just kept seeing my boost going down more and more after only about 2 hours of running it.then you see all the belt dust and you see the belt is glazed .i tried everthing and it still sliped ,and the reason i converted all my drive pulleys to cog is because i can run a 90 inch belt that should absorb the belt shock .anyways i allways take your advice and you do got me worried about my head unit ,but i tried what you told me and it worked for a`while but then the belt would just slip .now im going to try out the cog drive.thanks

 

When I last swapped from the cog drive to the 6 rib, I seemed to lose just slightly less than 1.5 psi at 6500. I was at slightly under 12 psi and it dropped back to ~10.5 with the 6 rib. I have some amount of boost variation at the top end when I ran it on the dyno last.

I will agree that the cog is a direct drive between the drive and driven pullies, and will yield the best boost. But, after having the issues with my head unit this last time, I am going to stay with the 6 rib for a while. Besides it is making good boost with the current set-up.

Have you received and installed the new cog set up? If so, how many miles have you put on the car since install? What do you think of the "Gilmer" sound? I think we are all waiting to hear impressions and see pics.

How much did your boost change? How did they manage with the AC compressor and the alternator? What tooth is your drive and driven. Do you have the blower maxed on impellor speed based on engine RPM?

Lets see those pics.

Aaron

 

Let's see some pix. I'm interested in this because I just completed a head/cam swap and may want to change my S/C pulley to bring my boost back up. Thanks in advance...

 

jsavoy,
Do you have room to go to a smaller driven pulley? Are you still far enough awqay from max impellr speed (MIP)? What model Procharger are you running on your '96?

You may can step to a smaller pulley without slip issues.

Aaron

 

I'm running the P1SC and I should have the room to drop the pulley size and stay within max impeller speed. I'm still researching and have a tremendous amount more to read / understand before I do the swap. I'm running an 8 psi system--no where near the 18 psi system you're running but I just want to take advantage of the systems potential.

 

aks,hi ,i got the pulley but have not installed them yet because we got about 2 feet of snow and the temp now is -31 so in my warm house i have been building my stealth ram plenum all the fab work is done now i just got to find someone to weld it up for me .but the cog pulley look great , as for the belt its a 30mm wide 8mm pitch and 90.5 inches long .and for the a/c pulley i sent him my stock one he machined off the stock 6 ribs and pressed on the new hub that he made on to it.and how did youi run a cog pulley on your car?because their is no room between the stock crank pulley and cross brace i see mustangs that bolt the cog pulley to their stock crank pulley but on a vette theirs no room.i would like to see pics of it if you have them,how did you do it .and when you say you had problems with the cog set up what did it damage in the head unit?did it destroy it .as for pics i will get my friend to post them for me because i dont know how to do it on here.but please the one thing i would like to no is what kind of damage the cogs did to your head unit,thanks in advance

 

Smokeshow that cog system sounds good.
By the way, did you get the bracket yet, and drew outlines and holes to paper?

 

I did mine a bit different than what you are doing. I had a new crak pully built by ASP that had a second 1.2" cog drive between the 6 rib and the harmonic balancer. Then I ran just the blower and idlers off of the cog. What was tough, was building the bracket, due to it having to route the belt "sround" the PS pump. When I built mine, the manufacturer (as well as all other manufacturers that I checked) were very implicit about no more than 15° backwatds bend in the cog belt. This approach kept me from doing what you are attempting.

As for the head unit, it is not really designed to have rapid "positive" back and forth movement on the step up trans. There is a lot of inertia in the trans and spinning impellor, and that is what happens with the cog drive (i.e. no slip). My trans just got really loose (read "noisy"), ATI says this is exactly what happens when you run the positive drive, but usually something catestrophic takes it out. Additionally, I had a friend that I set up with a cog on a F series blower and he lost the crank snout. He had a pretty nasty backfire at midrange while going across a large bump (railroad track here in TX), and it "ripped" the snout off the engine. The snout and harmonic balancer and shive were found across the road in a ditch. The engine kept running, but it required a total rebuild. Was it 100% the cog? Who knows, but the engine builder did not help in the cost because he was running the cog drive. Do I think your combo will end like this? No, but I do think that it will prematurely wear the head unit based on the amount of driving that you do.

Don't get me wrong, I like cog drives in the right application. For a full on race project, I think they are great! For a daily driver, or weekend warrior, I think other less expensive options are available.

I would still like to see pics of the cog drive when it is fully installed and hear your impressions.

Aaron

 

What kind of bracket are you gents trying to build? I may be able to add some guidance.
Aaron

 

hi,its the bracket for the d1 on a l98 it would be nice if someone can trace theirs out for me on paper and just send it to me .it would save me $500 ,and i would pay some one to do it .but thats what whe are tryn to do,by anychance do you got the d1 bracket laying around .thanks

 

As a matter of fact, look at the pics on the post "more boost, bigger SC". That bracket is a new D1.
Aaron

 

Hi Aaron,
I am just trying to get a drawing (which is exatly in scale) from D1 bracket to my car, becouse to get one from ATI will cost me a lot,, way too much, becouse I live in Finland and I can also fabricate better and stronger myself.

It is just much more easier to have the drawings, so there is something to start at.

I will do it like Yours, more belt wrap and little bit stronger bracket also. I am myself going to do 8 rib instead cog, becouse I have stick car and its dd.

I will be very glad if someone could draw me a direct copy of D1 bracket to paper and send it to me. I will offer a couple of cool frosted drinks to someone who can do it to me (or send the money, becouse I am not coming to States, least in a year or so)
Smokeshow already promised to get me a drawing, but havent heard it since. But I have trustful mind.

Offtopic/ but do You know where to get 8 rib pulleys to L98? I remember there was a topic in here where was a link to company which make 8 rib conversion to L98, but didnt found it with search.

 

Smokeshow and another guy are trying to buy a few of my spare D1 brackets. I wind up with them leftover, because typically I have been using my own bracket for the install. Maybe Smokeshow is going to copy the bracket once he puchases one.?

With regard to the 8 rib, a company named ASP here in Houston can set you up with all 8/10/12 rib set-up. http://www.aspracing.com/intro.htm

Aaron