I currently run an 8-rib conversion but I was wondering if anyone has ever tried running a 10-rib conversion? With the 3.4" blower pulley, I see some dusting of the belt...suspect it will get worse if/when I go with an F1 head unit. While changing my optispark, I measured the distance between the back of my 8-rib and the distributor and there is somewhere between .275-.300 space bewteen them...just enough space to squeaze two more ribs? It may require some shimming for adequate clearance. The down side is I can't find any 10-rib belts in the 54"-57" range. I would be willing to cut a 12 rib belt down to size if I could find the right length...any ideas?

 

Misc. info. on belts (posting it here so I can find it again)...

Detroit Diesel Astro D9K w/tilt, fan belt w/o fluid clutch, Gates part number: K100540 (10-rib, 54" long?) & K100570 (10-rib, 57" long?)...has anyone ever seen one of these belts? Do they even look like automotive belts or are they something all together different?

 

Chris
I am sure a 10 rib can be done. As you mentioned may have to shim it alittle. Here is a nother source for belts. mailto:info@beltsforanything.com?subject =Contact Us - Website

 

I think when you step up to the F1 you need to be thinking cog... I have a F2 and was running a 12-rib... it slipped... I know some of the guys who have C5s run the F1 with a 6 rib.. but that belt has to be slipping like crazy...

 

Actually, I have been thinking cog drives, too. It's a lot of work to put one together and I can't seem to find anyone willing to do it on a one-off project without breaking the bank.

If the price is right, perhaps we could get one of the sponsors to take this project on (TJWong??). How many folks would be interested in either a 10-rib or cog drive conversion for their ATI (P1SC, D1SC, or F1--sorry, P600B uses a different bracket style) LT1/4 based cars?

It would require:
-crank pulley being sleaved and machined
-keyed crank hub
-new bracket
-belt
-adjustible idler
-spring tensioner
-blower pulley
-hardware
-balancing

If there are no interested sponsors, I'll see what I can do to pull it together myself for actual costs, provided the group would be willing to cover the cost of my setup (I would show all receipts). I figure we'd need 10 or more people to keep the cost down and I would need your crank pulley for about two months (jan/feb??).

 

Aaargh. I just got done paying for my 8 rib.

...If I ever have belt slip with my future upgrades, I'll just add nitrous.

 

who makes a 12 rib conversion? or an 8 rib. Im gonna do a D-1 for my l98...... how much do those pulleys usually run?(8 or 12?) who made them?

 

There really isn't a C4 conversion kit for the LT1 based ATI blowers setups...it's mostly custom stuff. Sorry, I can't speak to L98 stuff.

 

As a refernce, I paid around $325-375 for my crank pulley from ASP which has a small 6-rib drive for the accessories which steps up to a 12 rib drive for the blower (I'll sell it if someone wants it!). Lee knows his stuff and totally understands the engineering involved. You are not going to be able to do a 12-rib that drives all of your accessories as I do not believe 12-rib belts are made that long. At least I couldn't find one. I guess could run two 6-ribs side by side like I did... but it didn't work very well for me... My guess is you are looking at $1200 or so for a 12-rib conversion.

 

Lee at ASP made the 8-rib crank pulley I'm currently running--the rest of the conversion I fabbed myself. He's a good guy and he would probably be the person I'd have mod the crank pulleys for this project. As you probably know, ASP will do an 8-rib conversion for the Vortech setups but not the ATI ones...at least they didn't when I converted to 8-ribs. I learned a few lessons when mocking up my 8-rib drive setup I'm currently running...highlights are outlined below:

The two main problems with the ATI conversion are the bracketry and tensioner. Once you have a dedicated belt driving your blower, you'll need a dedicated tensioner and a bracket to hold it. However, it's not as simple as bolting a tensioner to your ATI bracket. The blower placement with the new pulley is up, inboard, and back (up to have the volute clear the cross member, inboard to clear the upper A-arm, and back to get it to align with the new drive pulley location). If you go too high, the blower inlet elbow clearance with the radiator shroud becomes critical and you start getting into hood clearance issues (there's underhood support channel that is about 3" thick and runs directly over the top of the blower). Too far inboard and you start crowding the optispark, water pump, and belt angles feeding from and to the crank pulley start getting critically close as you must have an idler low enough to get the belt to clear the underside of the water pump...plus you'll need to have room for the tensioner, as well.

It's not terribly difficult to mock up a new bracket but it does take some time to get all the offsets and locations right. The hardest part of the project wasn't getting everything where it would fit, it was getting everthing where it would fit and having an off-the-shelf 8-rib belt the right length! (check the availability of 8-rib belts between 54" and 57" inches...I think there are only two size in that dimensional window).

To get a 12-rib to fit on an LT1 engine, you'd have to convert to LS1 coil packs and remove the optispark (except the crank sensor), which would free up enough room for that wide of a belt--10-rib is about the limit w/an optispark in place. If you went the way of coil packs and you could get a belt in the right length, I can't see any reason why it couldn't be done...hmm, interesting idea!

Thanks for letting me ramble-on about this stuff. I know there must be fellow LT1 owners frustrated with belt slip and I thought I'd share some of my experience on the subject.
CT

 

Hey Chris, at what boost level did you start to experience belt slip.

About the belt sizes. I think I'm running a 55 1/2" belt. There are sizes of a half inch between 54 and 57 inches. I used the Gates belt from Napa like you'd suggested. It didn't turn out to be as much of a problem as I thought.

 

I started seeing belt slip around 6-7 psi w/6-rib, 12-14 psi w/8-rib, and I'm hoping to see 19-21 psi w/out slip w/10-rib...I hope that helps!

 

Brand X,
What blower are you running that you are able to see these type of boost numbers. What RPM are you seeing these boost values? What RWHP numbers are you at with 20 psi?

I do not experience belt slip, am turning just slightly less than max impellor speed and I do not think I will ever see 20 psi. ATI claims that you can see high 30s with this head unit, yet I struggle to even reach 20 psi.

Are your heads, intake, cam, TB fairly large. I know that these items on mine are part of the reason that I do not see big boost numbers, but others seem to get there.

Thoughts?
Aaron

 

Aaron,
I've not hit +20 psi yet. I run a D1SC but was considering stepping up to the F1C. The most I've seen with my head unit was 19 psi while bypassing the intercooler (383 LT1 w/ported stock heads and mild cam...very similar to Bruce's combination). At those boost levels, I was seeing a 7 psi drop across the ATI intercooler (12 psi thru it, 19 psi bypassing it...hence all my questions about alky injection about a year ago and the reason why I sold my intercooler. I rev my car to 6500 with rev limiter set at 6800...which I often bounce off of when I experience traction problems. I run an 8-rib conversion with 3.4 blower and 7.6 crank dia. which puts me just over 62000 rpm impeller speed at the rev limiter. What combination are you running and what boost levels are you seeing? My new combination is in my sig. below:

 

Does anyone use that "sticky" belt dressing? Whats the pros and cons with it?

 

I've not used it...I too would be interested in hearing about it.

 

I have posted this before but i have
a custom made 1belt 10 rib system.

Not sure about the slippage, never saw more than 13 psi.

 

Try bypasing your ATI intercooler and let us know how much boost you pickup.

 

I know, that ati 2 core is pretty small!

QUestion about the 12 rib setup that you were having belt slip with. What size crank pulley was it and what blower pulley? At what rpm/boost levels did it start slipping?

 

btw, that last message was for tonydee