Green belt or black belt for superchargers?

[gjpundsack]

So, it's my understanding the Gates green belt for superchargers is more "flexible" than the black belt which is more "rigid". Which belt are y'all using? Any tips to follow?

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[Torinate]

In for info!

 

[Jay-rod427]

The gates green aka HD is not necessarily more flexible, just made with stronger fibers. It just won't stretch as much as the standard black. The rpm line of belts basically won't stretch at all, and requires a little more care setting the tensioner. I'd recommend the HD for sure if anything past a "stock" kit.

 

[gjpundsack]

The gates green aka HD is not necessarily more flexible, just made with stronger fibers. It just won't stretch as much as the standard black. The rpm line of belts basically won't stretch at all, and requires a little more care setting the tensioner. I'd recommend the HD for sure if anything past a "stock" kit.

Thanks. Good advice. I've ordered both to try.

 

[Angrey]

Thanks. Good advice. I've ordered both to try.

It has to do with stretch under load and then how the belt rebounds on sudden rpm drop.

Typically, with a stretch belt, you want the tensioner nearing it's fully tensioned position (like 70% or so) that way, when the engine is under load and it stretches, it has 70% of it's range to soak up the additional length (but still enough not to bottom out on the rebound).

With the RPM belts, as I understand it, it's a little opposite. You want the belt only tensioned as minimal as required for slip, as it doesn't need a whole lot of range to soak up stretch, however, on the rebound, if it's tensioned too far. it can max out the range and damage the belt (which will let go later) or even throw it.

I'm praying that I'm one of the lucky few who doesn't have issues (belt issues seems to be one of those random luck of the draw things, which is kinda frustrating given modern engineering), some guys run and have no issues with noise or throwing them. Some guys end up froth at the mouth mad for noise (under differing conditions) and or chewing up belts.

The green HD belt is definitely unsightly but it's the one whipple recommends. Other manufacturers may have different guidance.

 

[80FoxCoupe]

Gates HD green is a stretchy belt, designed for fleet use. Not specifically designed for a performance application such as the Gates RPM.

Green HD belt in the vid below, not ideal.. RPM has less stretch therefore requires less tension. Its also has more friction on the ribbed surface.

 

[Slow306stang]

I'm running the Gates RPM on my Procharger setup. It had zero slip when making 30-31psi on the dyno but i've yet to track test it. I was at about 25% of the tension that i ran on the HD belts. Like what has been stated already, the belt requires a lot less tension than the green HD belts.

I've always carried a spare belt regardless if it's the HD belt or RPM but the RPM belts do break when too much tension is applied.

 

[illtal]

I'm running the Gates RPM on my Procharger setup. It had zero slip when making 30-31psi on the dyno but i've yet to track test it. I was at about 25% of the tension that i ran on the HD belts. Like what has been stated already, the belt requires a lot less tension than the green HD belts.

I've always carried a spare belt regardless if it's the HD belt or RPM but the RPM belts do break when too much tension is applied.

So how "Slack" does the belt need to be to prevent snapping? I'll be running an RPM belt with a smaller upper,
I couldn't even get the belt on that was supplied with my kit, which was an 82" I ended up running an Conti 82.75" with no problems, The closest RPM belt is 82.59" which is what I got.
My installer said that he was a bit surprised how well the 82.75" belt fits and runs with no noise and virtually no slip. My auto-tensioner is about 50% travel.

 

[givemeadollar]

get an rpm belt for any supercharged application. Green belt is ok if you can't get an rpm belt in the correct size.

 

[Barrel]

Been using a Gates green HD belt the whole time I've been supercharged. 200 half mile passes and never chewed one up or threw one or snapped one. YMMV I guess.

Even when I cracked the snout of my crank and introduced a nasty wobble the belt held up through a full pass.

 

[fuelforfire87]

What supercharger were you running when you snapped your crank?

 

[Barrel]

What supercharger were you running when you snapped your crank?

D1SC

 

[fuelforfire87]

Been using a Gates green HD belt the whole time I've been supercharged. 200 half mile passes and never chewed one up or threw one or snapped one. YMMV I guess.

Even when I cracked the snout of my crank and introduced a nasty wobble the belt held up through a full pass.

D1SC

Same blower as me. You think its safer running a standard belt with the procharger since it has a dedicated drive? Also currently running a green belt.

 

[80FoxCoupe]

Same blower as me. You think its safer running a standard belt with the procharger since it has a dedicated drive? Also currently running a green belt.

Blower type or belt has no bearing on snout failure.

 

[Angrey]

Blower type or belt has no bearing on snout failure.

I'm not sure there's data to support either claim.

I can't imagine having to crank the shit out of the belt (tension) helps the issue. Not saying it's what causes it, but there's a reason the aftermarket and the vendors are developing crank supports (unless you think they're just gimmicks).

I would say different belts require different tension and it's that tension that's the concern (hence the crank supports).

Additionally, a blower that features a larger pulley (while still maintaining good flow) will be preferable to one that requires a tiny pulley (that either has to be tensioned like hell, OR requires cost of wider rib formats).

There's also the pervasive myth/concept that the further out from the face of the block you pull on the snout, the more leverage and strain you place on the crank (again, precipitating the need for crank supports).

So in a way, I think blower selection and belt selection play a role. To what extent is a reasonable debate.

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