I was trying to use Gates cogs belts for my Vortech application, but they only had cog belts sizes in 560-8MGT-20 and 480-8MGT-20, I need something more in the 520-8MGT-20 range, in between those two sizes.

I tried Jason Industries as well, but they said that most belt manufacturers use the same sizes.

Anybody knows a company that can create a custom cog belt size?

 

I have tried in the past to order custom gates cog belts but it turned out to be a big FAIL..If i remeber a minimum order of 200 belts was required for them to produce the particular belt i was looking for. What are you trying to do if i may ask?

 

I'm trying to run a 28/34 cog pulley combo on my built revup engine...I have a 928 blower that can get up to 60k rpm, and I wanted to avoid getting a 2.62 pulley becuase of slippage issues....

 

So you've tried both the gates belt and neither could have the slack removed with the idler pulley?

If thats the case, 2.62 with a GTM idler is going to be your only solution. That shouldnt slip anyhow.

 

The 560 belt was too loose; the 480 belt was too small...

Yeah, it looks like I'll have to get the 2.62 from GTM...I'll see if they can sand blast it for me for better grip...

I have a revup, so the GTM idler pulley mod dosen't work with my setup...

 

That's why i had to come up with this idea with Sam at GTM! Has been working great for over two years now. As you can see the belt has more contact area around the pulleys so the cog belts last longer and can take more abuse than how vortech originaly designed it. This is how i went about installing a non revup cog pulley setup on my revup kit. 28/32 cog pulleys instead of 32/34. i am using the 560 cog belt BTW as well as machined the lips down on the idler pulley a bit for added clearance.

 

I just called Sam...He dosen't have the original template for the bracket/pulley he made you, but he says he can re-create it if I bring him a blower, and it just so happens I have an extra one ...it'll delay the final max tune of my car a bit, but It'll be worth it in the end...

BTW, for those of you guys who are interested, GTM does not make the 2.62 machined pulley anymore...

 

but the same place you bought your blower upgrades (928M) makes pulleys even cheaper and all sorts of sizes......

 

Keep us updated on your build!! i am curious what your final numbers will be with a built rev-up and running the 928 impeller with your pulley combo. What serp pulley size have you decided on? i am running the 2.87,32/28 combo. I would love to see you throw a T-trim on that and realy spool it up!!!

BTW what compression ratio are you running on your built engine?

 

Well, after further conversations with Sam, it looks like he's too busy to work on the bracket. For now, I'll run a 30/34 cog pulley combo with a 2.75 from 928 Motorsports, that'll get me to around 60k rpm on the blower. My engine is a stage 2 IPP engine with JWT S7R cams for revup, and wiseco 9.5:1 comp pistons (had to wait forever for those since the it's a custom compression piston).

As for the T-trim I would love to do that, but it's only rated to 55k rpm...so we'll see what the 928 can do ( and I still have my carb number on my blower lol). I will be more than happy with 500 whp dynojet with meth, I don't need to beat pharmd ....but who know's, we'll see...

 

just did that ordered a 2.75 pulley....any idea if I have to get it machined for it to work?

http://www.928motorsports.com/parts/6ribpulley.php

 

u might have to get it machined, but thats only like 1 minute on a lathe

 

Nice setup, I wish I had gone with higher compression and a wilder cam. I think urs might just put yours over the top... cant wait to see

 

I took you advice from your build for the pistons

as for the S7 I don't know if it's any more agressive than your nismos...

Please sell me you Reichard Racing pulley, lol

 

I'll do my build/dyno thread here since most of the Vortech guys are already probably reading this thread

As promised, here are the results. The yellow readings are no meth, and the green is with meth.

Keep in mind I realize that Dynapacks read higher in general; in the future I will re-dyno with a dynojet to get a more standardized comparison. However, I do know I am over the 500whp range for sure dynojet; that was my goal all along, so I'm content <b>for now</b> with the results.

Also, with the issues I had with the cog belts, I'm not at the 60K rpm limit of the 928 impeller. I am still currently running the 2.87 pulley which gets me to 57k rpm, but I just got the 2.75 from 928 Motorsports which will get me to 60krpm, I just need to have it machined and sand-blasted for my setup, and we'll see how much more I can get.

Props to IPP for the great motor (thanks Kyle!), 928 Motorsports for their impeller and great rebuild of my Sc trim blower (thanks Carl!), Project Import for the great, thorough engine install, and Church Automotive for the great tune as always(Thanks Shawn!).

Also props to Mr_pharmd, and str8dium for breaking the 500whp mark with the Vortech and giving me something to shoot for past my 400whp goal, and all the rest of the Vortech guys for the great info in this forum and the guidance. Enjoy the clip.

http://www.youtube.com/watch?v=eIhIMGi2-JE

Oh...and for those wondering about the huge delta between whp and torque, I think its probably inherent in centrifugal superchargers and perpetuated further by a revup setup, which tends to have less torque than its non-revup counterparts.

 

What were your number like before this last tune?

 

My previous dyno was with my stock block and an Si trim blower w/ Meth...I was getting about 457 whp/390 torque on the same dynapack dyno...

 

That is a nice gain going from the Si trim to the Sc trim with an impeller upgrade. You gained 77whp and 36lbs TQ on the same dyno. Were there any other changes made?

Also were the privious numbers on meth?

 

77 whp with no meth, yeah...a much bigger gain w/ meth...

As for other changes...

IPP Stage 2 Built block w/ JWT S7R cams
30/34 Cog pulley combo (up from stock Revup 32/34 pulley combo)
Bigger Intercooler

 

now get out there and pop off a sweet 1/4 mile time!