NVRENUF

I have an '89 IROC with a D1SC.The new engine is on the Dyno right now.It's a 421 c.i.,Dart SHP block,AFR heads etc etc. It has a 3.40" blower pully and the stock ATI crank pully.We are looking for 15 psi boost.We had the belt ATI recommended (sorry,can't remember the lengths) as tight as the tensioner would go, at 9 psi it started slipping at higher rpm.They got the next size shorter belt (approx 1/4" shorter) a total bitch to get it on.It made 11 psi & started shreding the belt as the big front bracket started flexing & the belt rolled over the lip.The engine made 720HP & 720LB/FT with not much timing in it,shooting for the 800 - 900 range.

What has anybody done or used that will eliminate belt slippage? We were talking about a cogged belt set up,not sure if it was ATI who made it?.I'd only have to change the blower & crank pullies then.Need to do something right away as the engine is still on there Dyno!

Thanks in advance

glock

GIVE ASSC RACING / LRS PERFORMANCE A CALL 847-838-0393 and talk to larry he makes a cog setup for our cars .... do you have a big block snount on that crank?

Tony89GTA

iTrader: (7)

I was able to get about 18psi of boost with the 3.4" and stock crank pulley on stockish car but it's a bitch, and I also have a 12 rib setup and a bigger tensioner pulley with a extra brace for the main bracket. You will probably want to go with a clog system if you can get it.

Gumby

Belt slip is nice if you backfire but you want a cogg setup if you want to never slip.

NVRENUF

glock...where is ASSC RACING / LRS PERFORMANCE located? Are they both the same business? Also, any approx idea on price? I'm assuming I would need just the blower & crank pully & the belt? Idlers??(hopefully!!)

I did some more research on here about this.A lot of different opinions on cog vs. adding a OEM style tensioner. Alot were older posts so just trying to get the latest up to date info.

Tony...how does the 12 rib fit width wise, especially by the fans? Would that also be a case of just getting the 12 rib crank & blower pullies? Old idlers work??

glock

http://www.asscracing.com/news.phtml call and talk to larry .... i have a 12 rib setup,there is some customizing you have to do for it to fit with a 2 fan setup .... with a cog setup u have to beef up that crank snount or more than likely you will snap it right off

Gumby

Been round n round it some with the Fagoel V6 Blowers [Got one, new never used] Well to lower the risk of backfire damage most change to serp belting that was stock on the V6 3rd gen but anyways it did helpped 2 ways. But rule 1 it was made for the stock 2.8, to small for a built 3.4 but those who tried had the typical slip.

Here was one solution that looked nice to keep max belt contact with the blower pulley.




Another is to go to cogg so it has to turn, but a smart man who isn't rich n can afford to blow up parts like racers, makes / buys a BOV.
Think of drag racing when you see them suckers belch fire n kick off the belt n just scale it down to your engine if it back fired, on damage n cost.

But cogg is the way

gta324

Here is what I did to prevent slip.

0. 12rib setup
1. spring loaded tensioner
https://www.thirdgen.org/forums/powe...ioner-ati.html

2. New bracket
https://www.thirdgen.org/forums/fabr...r-bracket.html

Will se if I get any issus this year with a 3,55" pulley

Tony89GTA

iTrader: (7)

The 12 rib setup fits fine with a stock rad not sure how it would be with something aftermarket. With the dual fans can't say I did anything special to them only thing I did was cut the upper rad hose end little shorter and zip tied it closer to the rad support. Not sure if your old idlers would work but mine measure about 2 5/16" across.

I was working on my own spring loaded tensioner setup to but I haven't tried it out yet, still finishing the rest of my installs, but here is a few pic's to give you a idea whats going on. I'll be making a post on this after once I can confirm it does work.

Tony89GTA

iTrader: (7)

Another idea you might want to try that helped me was sand blast the V's on the blower pulley to give them a rough surface instead of the nice shinny smooth paint that's on there. I also machined down the top of the V's just a tad since the belt grooves was riding on it and not the side of the V's for better grip.

You also probably want to add something to support the main bracket to stop it from bending in. You can add one from under the blower to the main bracket, the orginal owner of my blower did something like this but I plan to make something new that will attach to the heads, I'll have a pic of this later in the week.


Pic of my sand blasted and machined 3.4" pulley

NVRENUF

I phoned ATI today & he recommended NOT to use a cog drive set up as it may damage the blower as the D1sc was not designed for that.He said I'd have to go to the F-series race set up to use a cog system.He didn't really say exactly what might happen to a D1 if I used a cog set up...maybe due to the fact it has no slippage & no room for error?? Anybody used a cog set up on a D1? Any issues? He also said that they (ATI) don't list a cog set up or even a 12 rib setup for my year car(88-92) They have a 12 rib for a 93 & up.
He also recommend to get the pully coated from these guys http://carbiniteracing.com/index.html Anybody used or heard of these guys?
Talked to my engine builder as well, they are going to try some "green" belt,supposed to be a thicker, heavy duty(agricultural or ??) application & wont stretch.Has some mesh in it or something,not sure right now.

Probably going to have to settle for the 720HP that it makes now!! Get the engine in the car,get the pully coated & fab up a spring loaded tensioner,see if I can get 15 psi out of it & see from there!

Gumby

Probably a good idea, belt slip does save parts if there is a goof..........

But only a cogg won't slip.

glock

they did at one time offer the 12 rib for our cars ( i have a 12 rib setup ) and people have used the cog setup on d series and the only thing that usually happens is bye bye crank snount ...never heard of a cog setup ruining a d series...i think ati has to say that to protect there azz

NVRENUF

The engine builder got a Dayco "Gold Label" belt,tried that as well as strapping the back of the blower to the dyno to keep the bracket from flexing and it's worked so far.I'll try that belt & fab up some support bracket to help stop the main plate bracket from flexing.The engine made 794HP & 762LB/FT torque! Bring it home tomorrow & start the install process.

Thanks for all the advice/opinions

gta324

Yeah, flexing main bracket is not fun, I was bending my long bolts with procharger bolts and "spacers".......


How much boost and timing did you run?

NVRENUF

They got 14 PSI at 6,000 rpm. Not sure on the timing.I'm also doing the LS2 PCM & wire harness change over from EFI Connection.So it's now distributor less coil on plug ignition with there 24X set up.Reluctor wheel on the front of the crank,crank sensor in the front cover,what was the distributor is now a cam sensor....plus all the benefits of tuning an OBD2 LS2 Pcm! It's a great set up,very well made & way cheaper & better then a BigStuff 3 or FAST system.

GTA Sammy

iTrader: (1)

Make sure that you post vids of this Monster!!!!
Can't wait to see it!!!

badgta

iTrader: (4)

i think you might want to watch out for tight belts, search broken crank snount. you will see what i am talking about!

ZZ3Astro

This is the ultimate solution to belt slip

Kendol

And my solution to belt slip:



To each his own.

TransAmGTA88

Do you use the oem bracket for the alternator and power steering pump? I've converted my D1SC over to cog belt. Unfortunately the cog belt is walking under a load, meaning the main bracket is flexing. Trying to find a solution for my belt walking. The double plate setup looks pretty solid compared to a single plate bracket.