Whipple guys! Dropping pulley size to raise the boost, but is a belt change needed? - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Aries240SS · 05-18-2020, 11:29 AM

I've been running a 3.75" pulley for a while now with the stock belt, but reports vary on when you need a different belt to prevent slapping/shredding them. I'm about to drop to a 3.5" pulley and looking for real world experience on what belt to use, and wether to order the pulley from Whipple or go with a Griptec (or other maybe?). The car is 6 rib with no belt slip and will likely not go to 8/10 rib in the future.

Batmanntexas · 05-18-2020, 01:34 PM

For a 3.5" pulley, definitely go with a Grip-Tec, even with that, you may still get some belt slip. Yes, you will also definitely need a shorter belt. I'm running a 3.625" pulley on mine right now. I'll look at the belt number when I get home and post it here for you.

-Scott

POWERFREAK · 05-18-2020, 01:37 PM

I run a 3.5" pulley...I'll see if I can get you a # off the belt.

EDIT....sorry, I don't see a pn on it anywhere...but it is a 6rib (with no issues).

Greenhornet2 · 05-18-2020, 02:52 PM

Whipple has a good belt wrap and really strong tensioner i'm still on stock belt at 3.75". You'll have to get a shorter belt but i don't think you'll have a slip issue as long as your boost is reasonable

Juiced1 · 05-22-2020, 10:19 AM

If you drop from a 3.75 to a 3.5 a new belt might not be required. In stead of having charts on charts on charts to figure out every cars correct belt length for every pulley combo on the planet, we find its easier to just do a little research. First find out your current belt size and then look up on Gates website to see the next size smaller. If it's a big jump, wait till you decide to drop down again. If its just a bit smaller go ahead and give it a shot. Droping .25" on a pulley would not require a much smaller belt at all. Especially if the current belt was difficult to put on.

Aries240SS · 05-27-2020, 05:57 PM

Quote:

Originally Posted by Juiced1

If you drop from a 3.75 to a 3.5 a new belt might not be required. In stead of having charts on charts on charts to figure out every cars correct belt length for every pulley combo on the planet, we find its easier to just do a little research. First find out your current belt size and then look up on Gates website to see the next size smaller. If it's a big jump, wait till you decide to drop down again. If its just a bit smaller go ahead and give it a shot. Droping .25" on a pulley would not require a much smaller belt at all. Especially if the current belt was difficult to put on.

Good advice. Thanks!
The current belt was rather easy to put on, so I'll check the Gates page and see if there's something just a tiny bit smaller to use.

Now if I could just find someone with the griptec pulley's in stock...

05-18-2020, 11:29 AM	#1
Aries240SS Drives: 2011 1SS RS Camaro, 1995 LSX 240SX Join Date: Mar 2011 Location: Austin, TX Posts: 462	Whipple guys! Dropping pulley size to raise the boost, but is a belt change needed? I've been running a 3.75" pulley for a while now with the stock belt, but reports vary on when you need a different belt to prevent slapping/shredding them. I'm about to drop to a 3.5" pulley and looking for real world experience on what belt to use, and wether to order the pulley from Whipple or go with a Griptec (or other maybe?). The car is 6 rib with no belt slip and will likely not go to 8/10 rib in the future. __________________ 2011 Camaro 1SS Whipple Supercharged 1150/1100 @ 24psi - Removed blower and went Turbo Huron Speed T6 1135/1070 @ 20psi so far. 15 more PSI loading...

05-18-2020, 01:34 PM	#2
Batmanntexas Drives: 2012 Camaro SS (2SS) Join Date: Aug 2012 Location: Stafford, VA Posts: 1,394 View My Garage	For a 3.5" pulley, definitely go with a Grip-Tec, even with that, you may still get some belt slip. Yes, you will also definitely need a shorter belt. I'm running a 3.625" pulley on mine right now. I'll look at the belt number when I get home and post it here for you. -Scott __________________ 745RWHP/634RWTQ on 93 @ 10psi 806/676 on E85 @ 10psi Currently @15-16psi.... COTW 9/8/14

05-18-2020, 01:37 PM	#3
POWERFREAK I.AM. Drives: 2011 2SS/RS/A6 cammed-n-whippled Join Date: Oct 2008 Location: NY Posts: 2,637	I run a 3.5" pulley...I'll see if I can get you a # off the belt. EDIT....sorry, I don't see a pn on it anywhere...but it is a 6rib (with no issues). __________________ https://FeelingCreativeBlog.com Last edited by POWERFREAK; 05-18-2020 at 05:10 PM.

05-18-2020, 02:52 PM	#4
Greenhornet2 Drives: 2011 Camaro 2SS LS3 Whipple Join Date: May 2019 Location: Connecticut Posts: 1,925	Whipple has a good belt wrap and really strong tensioner i'm still on stock belt at 3.75". You'll have to get a shorter belt but i don't think you'll have a slip issue as long as your boost is reasonable __________________ Whipple 2.9 CAI ID1050x injectors ZL1 Pump JRE FPCM JMS Voltage booster JRE Rough Idle blower cam BTR .660 springs CHE trunnion kit 1 7/8 Speed Engineering Borla Atak JRE scoop 1.5" lowering springs BMR trailing arms and toe links Cradle inserts 704WHP 603WTQ 93 octane

05-22-2020, 10:19 AM	#5
Juiced1 Account Suspended Drives: 2012 2SS CAMARO 45th Join Date: Apr 2011 Location: St. Charles, IL Posts: 18,648	If you drop from a 3.75 to a 3.5 a new belt might not be required. In stead of having charts on charts on charts to figure out every cars correct belt length for every pulley combo on the planet, we find its easier to just do a little research. First find out your current belt size and then look up on Gates website to see the next size smaller. If it's a big jump, wait till you decide to drop down again. If its just a bit smaller go ahead and give it a shot. Droping .25" on a pulley would not require a much smaller belt at all. Especially if the current belt was difficult to put on.