Some tips on belt slip
Thread Starter
Le Mans Master
Joined: May 2000
Posts: 8,729
Likes: 1,508
From: Redmond WA
Some tips on belt slip
I know for years guys have been fighting with belt slip, myself included. I'm at a particular disadvantage because not only am I running the puny Corvette 6-rib, I've also pulley'd up so that I'm running a much smaller blower pulley (2.75) that "stock".
I'm able to max out the S-Trim and push 12psi into a very free flowing 396 with no belt slip... and to do it, I did the following:
- Use the shortest belt that you can get on. In my case that's a 50.0", but with the original pulley that meant a 50.5" instead of the Vortech supplied 51.0"
- I added a Reichard Racing ultra-grip pulley ( http://www.reichardracing.com/ultra_grip_pulley.php ), and though I can't swear its a big benefit, it sure doesn't seem to be hurting.
I had dreams of a cog setup, going to 8-rib, and so on, but since I'm working the S-Trim about as hard as anyone here and doing it without belt slip, it's sure an easier solution!
Personally, I do not think the benefit of the ultragrip is what most think: it has slits in it that looks like they "grip" the belt, but I think that's negligible. I think its the fact that air under the belt has somewhere to go. You could probably achieve something similar by drilling air ports through an old pulley (but that might cause it to be structurally unsound and explode at 60,000rpm, so I'm not recommending it).
- Dave
I'm able to max out the S-Trim and push 12psi into a very free flowing 396 with no belt slip... and to do it, I did the following:
- Use the shortest belt that you can get on. In my case that's a 50.0", but with the original pulley that meant a 50.5" instead of the Vortech supplied 51.0"
- I added a Reichard Racing ultra-grip pulley ( http://www.reichardracing.com/ultra_grip_pulley.php ), and though I can't swear its a big benefit, it sure doesn't seem to be hurting.
I had dreams of a cog setup, going to 8-rib, and so on, but since I'm working the S-Trim about as hard as anyone here and doing it without belt slip, it's sure an easier solution!
Personally, I do not think the benefit of the ultragrip is what most think: it has slits in it that looks like they "grip" the belt, but I think that's negligible. I think its the fact that air under the belt has somewhere to go. You could probably achieve something similar by drilling air ports through an old pulley (but that might cause it to be structurally unsound and explode at 60,000rpm, so I'm not recommending it).
- Dave
Team Owner
Joined: Mar 2001
Posts: 30,861
Likes: 293
From: Boston, Dallas, Detroit, SoCal, back to Boston MA
A while back an owner put a custom tensioner on his. A simpler hole in the stock one with a j-bolt. Says it worked pretty good. Don't know how long his accessory bearings lasted though.
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 60
From: Fremont Oh
Dave,
The 3.125 is what mine came with.. so the 2.75 is what I would consider as a a smaller pulley....
I run the goodyear belt and I honestly think that it does grip better. I'm running the 3.125 pulley I'm running the older 7 groove, ( I buy the 8 groove belt and trim one rib off.)
As a side note I know Greg with Blowerworks is working on a 8 groove system.
I hope this helps,
Mo
The 3.125 is what mine came with.. so the 2.75 is what I would consider as a a smaller pulley....
I run the goodyear belt and I honestly think that it does grip better. I'm running the 3.125 pulley I'm running the older 7 groove, ( I buy the 8 groove belt and trim one rib off.)
As a side note I know Greg with Blowerworks is working on a 8 groove system.
I hope this helps,
Mo
Melting Slicks
Joined: Jul 2004
Posts: 3,277
Likes: 32
From: Mission Viejo California
Anderson ford motorsport in clinton ill sells what they call "instaboost". I've used it in the past and saw 2 lbs more boost on a pretty warm day that what I saw everyday for the prior 25000 miles. It's a quick fix for the dyno or the track. It lasts a couple runs. It's like vht in stickiness.
Also, if you were using a stock pulley, you could glass bead blast it. I don't know about doing that with the reichard pulley since it's billet. I have a 2.85" reichard sitting at the house that I may try someday.
Getting 12 lbs out of an s trim isn't too bad. Heck, I"m having trouble getting 8 lbs out of mine on my 383.
Also, if you were using a stock pulley, you could glass bead blast it. I don't know about doing that with the reichard pulley since it's billet. I have a 2.85" reichard sitting at the house that I may try someday.
Getting 12 lbs out of an s trim isn't too bad. Heck, I"m having trouble getting 8 lbs out of mine on my 383.
Melting Slicks
Joined: Jul 2004
Posts: 3,277
Likes: 32
From: Mission Viejo California
Tossed on a 2.85" pulley on (not the reichard, but a stock type glass beaded one) with a 50.5" belt. The belt needs to be about a quarter of an inch or a third of an inch shorter. I still think that the belt not being super tight is costing me some top end boost.
How much boost are you guys seeing at about 4750 to 5000 rpm? I rarely get my car into high boost #'s in the 2 lower gears due to lack of traction and I don't want to be going over 90 on the street so I'm trying to figure out how much I'll see at redline when I run it at the track. I'm seeing 5lbs by 4000 and 7 lbs at 4750-5000 rpm. It doesn't seem like the boost is climbing much at that speed. Are you guys seeing similar boost #'s at that speed with your redline boost numbers of 10-12lbs?
How much boost are you guys seeing at about 4750 to 5000 rpm? I rarely get my car into high boost #'s in the 2 lower gears due to lack of traction and I don't want to be going over 90 on the street so I'm trying to figure out how much I'll see at redline when I run it at the track. I'm seeing 5lbs by 4000 and 7 lbs at 4750-5000 rpm. It doesn't seem like the boost is climbing much at that speed. Are you guys seeing similar boost #'s at that speed with your redline boost numbers of 10-12lbs?
Thread Starter
Le Mans Master
Joined: May 2000
Posts: 8,729
Likes: 1,508
From: Redmond WA
I don't think glass-beading provides that much benefit... my opinion is that the benefit of the Reichard is to let air escape.
With a 2.85 pulley you should be able to get a 50.0" on there, which is what I run.
For what its worth, I too run the Goodyear Gatorback belt.
With a 2.85 pulley you should be able to get a 50.0" on there, which is what I run.
For what its worth, I too run the Goodyear Gatorback belt.
Melting Slicks
Joined: Jul 2004
Posts: 3,277
Likes: 32
From: Mission Viejo California
eventually I may send in the pulley to reichard to have them do the notches. You can really feel the difference with the glass beading on there vs a regular pulley.
You're right about the 50" belt. I would have swapped out the 50.5" but I didn't want to spend another 2 hours making the change. Next time I have the belt off I'll make the changes.
You're right about the 50" belt. I would have swapped out the 50.5" but I didn't want to spend another 2 hours making the change. Next time I have the belt off I'll make the changes.
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 60
From: Fremont Oh
I'm also running the gator back belt as well, with my 3.125 I'm pulling probably about a pound more than you, at 6000 I'm tapping 11-12 pounds, but I have a 7 rib, I'm not sure if that is a major difference. It makes me wonder if you are pushing your self pass the efficicentcy of the S/C rpms... or you need to get your fuel in line, if you re runing to rich it will also effect your boost levels... ~just a thought~
Mo
Mo
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Melting Slicks
Joined: Jul 2004
Posts: 3,277
Likes: 32
From: Mission Viejo California
I believe that you're correct with the efficiency comment. I'm sure that the air going into the motor is really hot based on what other guys have data logged when they spin their s trims hard. I'm hoping to really get some good cooling effects with the alky kit to offset some of that. Who knows, maybe I'll actually pickup a little boost once I switch on the alky since the air will be slightly denser(just speculation).
Melting Slicks
Joined: Jul 2004
Posts: 3,277
Likes: 32
From: Mission Viejo California
Dave, how hard was it to get the 50.0 belt on there with the 2.75? I know I could get away with a 50.25" without too much trouble, but 50.0 is probably going to be a bit of work to get on there.
Melting Slicks
Joined: Jul 2004
Posts: 3,277
Likes: 32
From: Mission Viejo California
Originally Posted by Baldturbofreak
how bout a skateboard wheel on a spring loaded arm right on the pulley to enhance wrap? maybe even two running right on the pulley for more than 180 deg of wrap?
Here's a link to a thread with their setup on it. I wonder how I can get mine like that.....
http://forums.corvetteforum.com/show...ap&forum_id=86
Last edited by qwiketz; May 30, 2005 at 01:34 PM.
