Accessory belt sizes, Superchargers, other additions/deletions

The Vortech belt for AP1 is 4060510 (6PK1295) It is 51" (1295cm) and used with 5" Vortech factory supplied pulley. Vortech belt for AP2 is 4060500 used with the 4-1/2" pulley.

Belts for Vortech:
4060510
4060505 (6PK1285) 50.5"
4060500 (6PK1270) 50" used with 4 to 4-1/2+ inch pulley May stretch and become loose on 3.8"
4060495 (6PK1255) 49.5"used with 3.5-4.0 inch


COMPTECH SUPERCHARGERS

For Comptech:
4060400 Standard AP1
4060395 4.25inch
4060390 4.0inch(7#)
4060385 3.5 3.35inch
4060380 3.25inch
4060370 3.0 inch

belt for removing AC: 4060450 (6PK1145) 45"

Factory belt: 4060578 (6PK1480) 57.8

Gatorbacks are available in all these sizes.
Chart modified 4/16/06, 7/4/06, 11/02/06 Thanks to Modifry, FF2Skip
Summitracing.com and others are good sources for Gatorbacks. Some sizes are not in stock and may take additional time to obtain. I suggest you plan ahead.
Additional reading on pulleys: http://www.s2ki.com/forums/index.php?showtopic=380286&hl=

A good source for pulleys with a non-skip lip is ASP Racing You must call them since our pulleys are not listed on the internet.

Thanks for this. I've put this thread into the FAQs.

Will:
4060490 (6PK1245) 49" used with 4 inch pulley

the belt above work with a 3.8" pulley?

3.8 inches is right at the limit. Let us know how it goes.

man i have a 3.5 pulley but i don't know what belt to get (comptech)

The Comptech SC uses shorter belts. Unless I'm mistaken the stock is 40 inch and the one I'using with my 4 inch pulley is 39.

You can roughly work out the difference. If I'm using a 39 with a 4" then the Pi * R (6.3") is the approximate length of the belt going around the pulley. That is because the circumference of the pulley is 2 * Pi * R and we're assuming the belt covers 50% of the circumference and R is D/2.

So if you do the same maths for a 3.5" pulley only 5.5" is around the pulley. The difference is 0.8 if an inch. So I would recommend a 38" belt and I'm willing to bet the part number is something like:

4060380 (6PK0965)

does this sound right for the 3.5 pully i read this somewhere

The brand is Dayco and the part#560390

Well call me psychic but I'd say that was a 39" belt. Assuming you have a Comptech SC that will probably fit. Your tensioner will just be a bit further in than mine.

huh, i am comptech?

The 'psychic' bit referred to my inate ability to determine the belt length from the part number.

My calculation suggests 38", someone has recommended 39". Either way it's pretty close. I'd say try the 38 and if it is too small, exchange for a 39".

oh okay sounds good. i should still treat this like a 9 psi pulley and not a 7 psi one right, b/c i'll be running 8 psi with it

I'm lost. My 4" gives me 8psi before AC. And even with the AC it's the same amount of air even it it exerts less pressure.

I'm not sure what you mean by 'treat'. Just install and tune.

i mean is it where you can use the fpr and tune or should i get an emanage and some 440's and go from there?

Personally I don't think you should run the stock pulley with just the FPR so my answer is pretty obvious.

I recommend the AEM EMS, bigger injectors and a tuner with a brain the size of a planet.

If you can't do that then an E-manage and 440cc injectors.

If you can't afford that don't mess with the pulleys. YMMV.

sweet, j/w what'll work and what won't. i have emanage and 440's on the way so i'm just waiting for that.

I ended up using If I remember correctly the 49", I think its actually a 49.5". But I also had to get a bigger size tensioner pulley, which I happened to find at my local auto part store. If I didn't get a bigger pulley, the tensioner was already at 1/2 its travel, making the belt only slightly tight. So now its good to go. Gotta go tune w/ my new pulley, head, etc...

ON my way to changing my pulley down to a 3.5 from 3.8". Rerouted piping on intercooler and gained 1psi.

So i'm still looking for lost PSI.

Else, im gonna go back to the aftercooler


We will see how much boost gets picked up from a pulley change from 3.8 to 3.5"

Using a 3.5 inch pulley limits your redline to 8500 rpm whereas your 3.8 inch pulley is good for 9300 rpm. Don't exceed the maximum impeller speed.

http://www.s2ki.com/forums/index.php?showtopic=303549

Yes, I did take that into consideration.

But its all right, overspinning a few times for a quick second will not kill it.

If I go to the track though, I plan on dropping the shift point to 8,000.


However, if it doesn't gain that much boost, then I will swap back to 3.8 and live PSI less or go to a front mount bigger water intercooler or like I ultimately planned

go turbo
The dyno will tell the verdict...

I have a Comptech pulley that measures 3.4 inches OD.

Anybody know what boost it's considered to be???

I didn't see a Comptech belt post and just ran across these notes I made when I replaced my belt at 50k.

SC belt (std pulley) - NAPA 25060400 $17
21x1035mm 6 ribs 40° angle

stock serpentine belt - NAPA NBH25060578 $27
21x1483mm 6 ribs, 40° angle

k,
I just ordered a 3.35 pulley from ASP and wanted to make sure I have the right belt for install. So far, I've been told to get a 4060390 (39"), but I wanted to get also a couple of other sizes just incase that one doesn't fit right.

So correct me if I'm wrong but 39" is the biggest/longest I will need right? So I should also get 4060380 (38") just incase and not to worry about a 37" because that will be way too small right?

It's for an 04 CTSC

From experience, the Comptech 3.35" pulley needs a 4060385.

The Comptech 4.25" pulley uses a 4060395

whats the belt size for n/a without the a/c...

Hey Pinyo, can you route something around the pulleys and measure the length of it? A tape measure would work, I think. This should give you an idea of the needed length. I could help you from there.