What makes COGs UN-Streetable?
07-14-2007, 02:35 PM
#1
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What makes COGs UN-Streetable?
Everyone Ive told that hears Im putting a COG Pulley setup on my supercharged Trans am flips out and tells me cogs are unstreetable and that im gonna hate it...but nobody can give me a straight answer as to why...
It seems that everyone with ribbed pullies tries to get the widest belt they can in order to not slip...so if not slipping at all and having the most ""traction" is everyones goal...why wouldnt a cog setup be everyones pinnacle?
The cog tensioner can be run looser to allow for less tension to be put on the bearings and snouts of the crank and blower, so it seems like itd be a safer and more reliable setup...with NO SLIP
Anyone?
It seems that everyone with ribbed pullies tries to get the widest belt they can in order to not slip...so if not slipping at all and having the most ""traction" is everyones goal...why wouldnt a cog setup be everyones pinnacle?
The cog tensioner can be run looser to allow for less tension to be put on the bearings and snouts of the crank and blower, so it seems like itd be a safer and more reliable setup...with NO SLIP
Anyone?
07-14-2007, 08:00 PM
#3
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I think the answer is, that rib belts do slip on deceleration.
I believe that the step up gear set inside our blowers, don't really like the shock when we pull out of the throttle. The tensioner on a rib belt setup absorbs some of that shock. Allowing a little slip when the motor goes from 6500rpm to Idle instantly. A cog won't do that
Checkout this solution
click on the engine vid, you'll see the blower freewheel at shutdown. http://www.atiperformanceproducts.co...lley/index.htm
It appears to only come in 2 shaft sizes to fit Prochargers and ??, and that is not ATI/Procharger thats making it. That is ATI performance products (tranny stuff
).
As always JMHO ---Bill.
I believe that the step up gear set inside our blowers, don't really like the shock when we pull out of the throttle. The tensioner on a rib belt setup absorbs some of that shock. Allowing a little slip when the motor goes from 6500rpm to Idle instantly. A cog won't do that
Checkout this solution
click on the engine vid, you'll see the blower freewheel at shutdown. http://www.atiperformanceproducts.co...lley/index.htmIt appears to only come in 2 shaft sizes to fit Prochargers and ??, and that is not ATI/Procharger thats making it. That is ATI performance products (tranny stuff
).As always JMHO ---Bill.
07-15-2007, 06:30 AM
#5
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I'm still confused, but it not that hard of of task to accomplish
07-15-2007, 10:24 AM
#6
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The lack of slippage puts a lot of strain on the whole thing when the rpm suddenly changes. Race cars just don't see enough duty cycles for it to be a problem. I suppose that an auto with a loose converter might be ok with cogs on the street. But to get back to basics, why do you need a cog? Even a 4th gen has enough room to run a 12-rib, with a little massaging. You can drive a bigger blower with a 12-rib than you run on the street anyway.
Rich
Rich
Last edited by rskrause; 12-11-2007 at 10:14 AM.
07-15-2007, 12:01 PM
#7
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>I'm not doubting you or anything, but if this is true, then why are we not rebuilding the head units when we put them in the actual "race cars" not for the streets? They go from WOT to idle instantly continuously.
I'm still confused, but it not that hard of of task to accomplish
I'm still confused, but it not that hard of of task to accomplish
After rereading what that sprag pulley is designed to do.
"The ATI Super Pulley uses Sprag Technology to release each time the blower is spinning faster than engine RPM – thus virtually eliminating belt failures when the car is pedaled at the drag strip. Also look for more boost between shifts, as the blower will not ramp down as fast as the engine during the gear change. Finally, the pulley will also reduce wear on your Supercharger by not allowing the gear drive to mesh in the opposite direction when spinning down."
Maybe first it saves the cogs on the belt, as the impeller is acting like a gear reduction flywheel on decell. It seems that would be hard on the belt, gears, bearings, and cranksnout.
I'd like to completely understand this too ---Bill. OBTW, I use a 12 RIB belt.
Last edited by sc68z28; 07-15-2007 at 12:04 PM.
12-11-2007, 09:31 AM
#13
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Yes, I ran the cogs and they are streetable
The ysi is however, not so much. The secret Ive found is to have the good belts. The first time I used a cheap rubber timing belt and it was destroyed in about 300 miles. The second, a gates 1040-8MGT30 has been fine and seems like a much stronger belt
The ysi is however, not so much. The secret Ive found is to have the good belts. The first time I used a cheap rubber timing belt and it was destroyed in about 300 miles. The second, a gates 1040-8MGT30 has been fine and seems like a much stronger belt
12-11-2007, 10:17 AM
#14
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To sum it up, they aren't needed on the street, so why bother with the expense and the possible problems? They do not need as much tension as a ribbed belt though, and this may be somewhat protective of the crank snout. I am sure there are people out there using them sucessfully on the street. I suspect it is a matter of luck as much as anything else - like those people who somehow have a stock A4 or 10-bolt last forever on the track.
Rich
Rich
