mypontiac

I will be going from a 3.90" pulley to a 3.40" pulley on my D-1SC.

I was told by ATI that the same belt would work (080645), but I see different experiences from posts on this site.

Anyone with this setup please give me your experiences with your belt size.

I figure that I will get the next size smaller and keep it on hand just in case.

Thanks!

mypontiac

Anyone??????

I have found past posts that the 080644 is still too long and the 080640 is too short (1/4").

If I get the 080640, can the belt be stretched 1/4"????

Thanks.

mypontiac

I have been doing some research.

When I originally put on my D-1SC with a 3.90" pulley the supplied Gates 080645 was very difficult to get on. I finally got it on by unbolting the SC and much effort rebolting it. The belt walked off when I started the engine and got ruined. I bought a NAPA 080645 and it went on in 20 minutes! I am still using this belt.

So I got some info on Gates and NAPA belt lengths to see what differences there might be between the manufacturers. Here is what I found:

NAPA:

080645: Length= 65.5"
080644: Length= 65"
080635: Length= 64.50"

Gates:

080645: Length= 65.25"
080644: Length= 65"
080635: Length= 64.25"

The difference in the affected pulley circumference between the 3.90" and 3.40" pulley is 0.785" (measured as 1/2 circumference which is touching the belts).

I was using a NAPA 080645 at 65.5" for the 3.90" pulley so the belt size I will need for the 3.40" pulley is 64.715".

The closest belt size is the NAPA 080635 at 64.50". Since this is less than 1/4" too small it is comprable to the Gates size that was sent with the 3.90" pulley which was also too small. Therefore, it should fit with the same difficulty as I mentioned above.

Does this sound right????

Thanks!

mypontiac

So am I the only F-Body on the list with the Procharger 3.40" pulley???

Like Willie just said in a recent post, "Where no man has gone before."

Need some input here!

biggtime

get the shorter belt and redrill the hole for your idler.

mypontiac

Thanks for the reply Biggtime.

I am planning on using the shorter belt. Dorian at ATI suggests trying to get it on as the belt will stretch over time anyway.

He did also say that he could send me different size idler pulleys if necessary.

I plan on doing this work over the Christmas holidays so we will see what happens.

gmgod

Mypontiac, do you have any pics of the twin intercoolers on your bird?

B4Ctom1

there is a sticky at the top of power adder here showing a twin intercooler setup

mypontiac

Hi Gmgod,

I posted a few pics on this thread:

https://www.thirdgen.org/techbb2/sho...hreadid=152214

gmgod

Thanks man, did you put your front fender ground effects back on? If so, did you have to mod them to clear the intercoolers and/or supply air to the intercoolers?

mypontiac

Yes. I did initially modify the front corner pieces. Looked pretty good and allowed the air to enter the intercoolers.

When I had my new hood painted and installed, I also got the front bumper and ground effects repainted.

While doing this work, the bodyman made the cut on the side ground effects even sleeker. He has worked on my cars for the last 5 years and is very maticulous.

I can send some photos later.

mypontiac

Just to finish off this thread.

The correct belt for the D-1SC with a 3.40" pulley is a NAPA 25080635: Length= 64.50".

I just installed mine with the help of my wife. I had to remove the driver's side top bolt, the two passenger side bolts and loosen the bottom driver's side bolt of the blower to get the belt onto the pulley. I then pulled the blower into place and she threaded and tightened the two larger bolts. I took it from there.

The belt rides on the pulleys just fine.

I took it out for a ride and was able to get 12# boost . Too much traffic to go all out. ATI expects the blower to produce 15# on my set up.

This will give me 460 FWHP. Not too bad for the little 305!

I plan on tuning the alky injection over the holidays to ensure that I am getting zero knock.

This is the end of my project. Hope others can get some help from my experience.

Happy holidays!

gmgod

pics, pics, pics, (of front ground effects) . I am going with the d-1 and twin hi flow's on the 92 bird.

mypontiac

I wasn't happy with the way the 3.40" pulley made the car run in cold weather.

It would cause the supercharger to vibrate badly.

So I went to a 3.70" pulley.

I am now going to try a 3.55" pulley afer all of these years!

I will advise of the outcome.

Tony89GTA

iTrader: (7)

Nice to see your car is still working 7 years later lol

Where you getting this 3.55" pulley? didn't know procharger made one for our cars.

mypontiac

I just called ATI and asked what sizes were available for the D-1SC.

The 3.55" was the next size up from the 3.40".

The car popped in cold weather with the 3.40" so I stopped using it 7 years ago.

Call em up and for a c-note they will send you one too!

Sean

Tony89GTA

iTrader: (7)

I got the 12 rib setup might be why.

Good luck with the new pulley.

3rd gen Will

iTrader: (8)

Yea the options are far less for the 12 rib vs the 6 and 8 rib setups.

Here is a great site that sells/lists all the pulley's procharger has available.

The offset is the one you need for the P/D/F series unit's on the Fbodies.

http://www.houseofboost.com/store/su...s/cat_162.html

mypontiac

Thanks for the update!

Sweet.

OUTATIME GTA

iTrader: (2)

Hey guys - Sorry to bring this classic back up 2 months later and change course a little, but I thought I'd get some good "power adder" minds input.

Thanks for the pulley info link btw 3rd gen Will. Who is the best priced vendor these days for ordering procharger pulleys?

I have purchased from D'agostino Racing and direct from ProCharger. Always seems to be around $80-$90.

In the past 2 years I have changed pulleys from 4" to 3.7" and recently had a friend fabricate a pretty trick extra bracket to help reduce the main bracket flex issue I was having to reduce slippage.

After all that I'm still only getting 6psi with a P1SC kit that's only a couple years old. This is on my aftermarket TPI|Trick Flow headed|Comp cam'd, but still stock short block, GTA 350.

I was planning to drop down to a 3.4" pulley next year, but it seems to me I should already be closer to 10psi at this point, which is my goal. Any thoughts? Thanks. ..

3rd gen Will

iTrader: (8)

I haven't purchased any pulley's so your guess is as good as mine as far as cheapes place. I have seen quite a few pulleys go for around 50-60 on ebay new and used though.


What PSI @ RPM are your pulley's set up for? w/ better flowing heads/cam it's not uncommon to be a couple PSI below what procharger says. Their #'s are typically for stock setup's, if you don't have boost leaks and are making less PSI than you expect, you would actually be making more power because your engine is flowing the air through VS it stacking up in the intake. You are actually moving more CFM of air through the engine which is what makes power.

Tony89GTA

iTrader: (7)

Well since our cars are sorta simular having heads intake and cam change I can tell you with my D1SC I was making about 8psi at 5500 rpm's with the 4" pulley and with the 3.7" it's making 10 psi. It's about a 2 psi drop after heads and cam change from stock but now I usually rev to 6k so it adds another 2 back in. Not sure whats the difference in boost the P1SC will make compaired to my D1SC, no one here has ever posted a boost chart at the different rev's.

OUTATIME GTA

iTrader: (2)

Thanks for the reply. I'm aware of how the supercharger works and the expectations of a modified engine vs stock.

The ATI advertised ratings for P1SC was I think 9/12psi on a stock motor (w/2-core intercooler), but that is with the 4.25 pulley that it came with.

I've changed pulleys twice, 4.25->4->3.7 thinking that 5 tenths of pulley size drop would make up for ~5psi worth considering my setup is far from stock.
I do have the 3-core intercooler btw. No major boost leaks to note. We did notice the surge valve did leak some and capped it during testing which showed minor gain. Going with a BOV shortly.

Seems to me that there are plenty of streetable head/cammed ProCharged cars running ~10+ psi. My setup can't be that efficient at moving air can it? haha.

Tony - Yes, your car is a similar example I've seen over the years to compare, but yes it's the D1SC instead so it's hard to say. I think I'm missing at least 2 more psi somewhere at least.

OUTATIME GTA

iTrader: (2)

Forgot to mention I'm still using the FMU/24lb injectors, but moving towards 42lbs, a 749 ecm swap and SD/2-bar setup this winter.

Tony89GTA

iTrader: (7)

You might want to consider using EBL since you haven't already converted over, looks like a great way to go plus you get to keep some of your emissions systems working. I find the 749 system kind of a pain in the *** to work with and more setup for the V6 but with the code 59 it's still workable. Also you might want to go bigger on your injectors the FMS 42's I had before never really idled very well, my siemen 60Ibs work much better plus I have room to grow.

OUTATIME GTA

iTrader: (2)

That's funny, you just posted this while I was reading the dynamicefi site on the EBL. I've not kept up on what's out there and have already purchased everything I need for the 749 swap and 42's however, doh!

I did buy some SVO green tops, not from FMS though. I have a very experienced tuner helping me with that aspect whom has had amazing results with this swap on his '87 Corvette. We were never able to really perfect the idle and cold start issues on my current MAF setup, so I hope this is a step in the right direction. Not to mention ever being able to tune for boost. Unfortunately all this probably won't do much power wise I don't think, just getting rid of the band-aid FMU. It's been awhile since I calc'd, but I thought 42's was leaving me a little room to grow already.

3rd gen Will

iTrader: (8)

Procharger rates the P1sc at 1200cfm 30 psi and the D1 at 1400cfm and 32psi.

With a P1SC unit, assuming you have an 8" crank pulley with a 4.25 pulley you would see around 7.5 psi @5500 rpm and 9.4 psi at 6000. going to a 3.7 pulley would get you 10.5 @ 5500 rpm nearly 13spi at 6000, all of these figures are approx. for a stock TPI engine.

For reference 8" crank 4.25" blower at 6k rpm, A P1 puts out 9.4 psi vs the D1 should make 12.1 psi All things being the same except using a 3.7 blower pulley The P1 should make 12.9 and the D1 16.1

OUTATIME GTA

iTrader: (2)

Thanks, good reference points there.
So that being said, if ~13psi@6000 on stock TPI with a 3.7", you would think my peak 6psi@ roughly 5500-6000 is under par, no? I think it should be closer to 8 at least! I just hate to throw yet another pulley, the 3.4", if there is something else I'm overlooking. When I last spoke with ProCharger they said much like anyone else would; check for bracket flex/slippage/leaks, which I think we've covered.

3rd gen Will

iTrader: (8)

yea I'd say you should be at least at 10 psi. My buddy's car is missing about 7 psi also, and he has a cog setup so we know it's not belt slippage, he is pulley'd for 18 it makes 11. We think it might be the surge valve or a piping leak.

OUTATIME GTA

iTrader: (2)

Keep me posted if you guys discover where that 7psi went. I got back maybe 1psi just by capping the surge valve during testing. Not sure where else to look for a few more psi other than getting a smaller pulley and maybe having it coated to reduce higher rpm slipping possibly.

3rd gen Will

iTrader: (8)

Well with a smaller pulley you just winding the blower up even more, which you shouldn't have to do. Have you looked into the Reichard pulleys? I guess if you slip with those though it trashes the belt, no personal experience w/ them.

OUTATIME GTA

iTrader: (2)

Yeah I've read and talked to the Reichard folks before. They claim as long as you're aligned properly, it won't trash the belt.

I got some good info/feedback about Carbinite Racing and the coating they add to pulleys.

Not sure what else to do at this point. It would have to be a noticeable boost leak I'd think to be losing 3+psi

3rd gen Will

iTrader: (8)

I'd sure hope so! I have seen a kit that had a cap for both ends and one of them has an air chuck fitting so you can pressurize the system to find leaks. I am thinking that would be a really helpful tool!

Tony89GTA

iTrader: (7)

A simple fix that you might want to try is sand blasting your pulley, gives a nice rough finish to make it more grippy. I did this on my 3.4" pulley and found it did help a lot. One thing to make sure of is the top of the V's on the pulley ribs that they are flattened off, one of my pulleys the ribs were a perfict V and made the belt ride on the top of the V and wasn't able to grib the sides of the V, I machined the tops flat and made a world of difference also.

Pic of my sand blasted pulley to give you a idea, be lot cheaper then getting it coated or messing around with a new pulley.

OUTATIME GTA

iTrader: (2)

Unless I truly have no major issues and I want 10psi, right?? In all honesty I could care less about the # of pressure. Just want to get closer to mid 11's in this car with this setup. Considering the price of these kits, I don't think I'm asking too much from it. I'll also be changing the converter next year to match the cam better which should help the cause.

Nice ideas and visuals. Gives me something to think about.

Tony - Any measurable difference noted with that coating? Your earlier post said you are using 3.7". Is this coated one a separate 3.4" that you have layin' around now? Doubt you'd go backwards. Wishful thinking, heh.

There's also a guy on eBay that constantly has auctions for doing what Reichard does to pulleys for a lot less with the slots and he puts holes in them too for supposed weight savings. I prefer to try the coating route first, sounds safer.

Tony89GTA

iTrader: (7)

Yes is a spare pulley I was using when I was running stock heads and cam making 16psi. I was having lot of problems with belt slip then after blasting it down to the bare metal I found it keeped the boost at a steady repeatable level.

OUTATIME GTA

iTrader: (2)

I forgot you were using a 12-rib setup. Would've asked to give it a whirl on mine if it was 8.