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finally got my c30-74 rotrex setup running and dyno'd.
At the dyno, the car shredded a belt but i had another and we pushed on. Ended up with this even with the belt slipping past 7k.. Flamesuit on for low torque.
I guess the question i have i can i convert to a 6 rib setup with a supermiata s/c damper? 949racing says it wont work, but my pulley has 2 more ribs on the front side and the spm sc pulley says its the same alignment as a stock pulley but with two more ribs out front. my basic math tells me it would work. ill just need a new pulley for the rotrex aswell.
Blower has a 80mm pulley. About 9 psi before it slips. slip indicated by the rubber everywhere/hot belt and the belt breaking and the psi tapering off at high rpm
Your pics make the ic look like its supposed to fit there.. this is also a much bigger ic hence the pain in the *** to make fit
Blower has a 80mm pulley. About 9 psi before it slips. slip indicated by the rubber everywhere/hot belt and the belt breaking and the psi tapering off at high rpm
Your pics make the ic look like its supposed to fit there.. this is also a much bigger ic hence the pain in the *** to make fit
With the four rib set up they can slip when you go too small on the pulley, but I've only heard of problems with the 75mm pulley. I've never moved on from my 85mm pulley and have never experienced any issues with it. Are you running A/C and P/S? What size belt?
no a/c or p/s. the belt is a 4pk1160, its the smallest i could fit for maximum wrap. im starting to think the no PS is the issue. there is no guidance up there by the blower and the belt being longer stays cooler.
Great numbers for the smaller Rotrex. I bet the intake plays a big role.
What’s up with that throttle body-IC tube funkiness. Square up that TB plate and you’ll be left with a straighter shot to the intercooler. Get some good bends and loose all those goofy pie cuts. I bet you can make the transition in 1-2 cuts.
I wish i could ditch the pie cut piece but I was having issues with the spm radiator and the charge pipe. The intake manifold has the tb pointed toward the center of the car so not much I could do. I’m not happy about it, but it works!
Regarding belt sleeping, I don’t think a 6 rib setup would help. That rotrex support is flexing , that’s my guess as I’ve seen before, it even ended up breaking on the top of the rotrex where the support its thinner.
I wish i could ditch the pie cut piece but I was having issues with the spm radiator and the charge pipe. The intake manifold has the tb pointed toward the center of the car so not much I could do. I’m not happy about it, but it works!
look closer at the intake. That looks like a bolt on adapter that’s causing the throttle body to be cocked. Can you machine that piece square?
You say you have 2 more ribs on both the SC and the crank, and they go the proper direction? That kinda sounds like a no-brainer to me. You can space the autotensioner forward, and get a different pulley for it.
Edit: i have no experience with Rotrex, but I DIY superchargers.... an additional bracket on the back of the SC makes a world of difference.
So I had a giant clusterfuck with 949racing and bhj but luckily bhj is semi local to me and I was able to get the right crankpully and overlay to run the 6 rib setup. It took some work but I got it done.
i replaced the crappy small bearing manual tensioner pulley for a Hyundai Elantra timing belt idler.
Then i spaced in the auto timing belt pulley a few mm closer to the bracket.
Found my 6 rib belt for my new blower pulley and hit the track. No belt dust and the belt lasted the entire day no problem.
Ill hit the dyno later later this month to confirm no more belt slip and consistent boost. but I’m pretty sure it’s fixed
the spm supercharger pulley is not the same alignment with two more ribs out front. It’s actually one rib on each end of the stock pulley. This was why I had to space the auto tensioner in closer to the bracket
i was actually gonna use the exhaust to spin up a pinwheel with an extra flywheel i have so even when im not accelerating the pinwheel can propel me in a forward direction to make me faster.
I was able to get the right crankpully and overlay to run the 6 rib setup. It took some work but I got it done.
i replaced the crappy small bearing manual tensioner pulley for a Hyundai Elantra timing belt idler.
Then i spaced in the auto timing belt pulley a few mm closer to the bracket.
Found my 6 rib belt for my new blower pulley and hit the track. No belt dust and the belt lasted the entire day no problem.
Twibs,
I want to go to a six-rib setup for my Rotrex C30-74. I have the same problem--80mm pulley, no p/s or a/c, and I can only get to 9.3 psi before I get belt slippage.
Could you be more specific about the parts you used?
I'd be interested in anybody else running a six-rib setup on their Rotrex for the track, as well.
Thanks much,
Last edited by poormxdad; Mar 19, 2019 at 10:00 AM.
Bhj supercharger pulley and overlay. No longer avalible As far as I know. You could substitute for a stock pulley overlay. Make sure it’s one that retains a damper
i tossed out the plastic idler pulley and used a full metal wide bearing 2009? Hyundai Elantra timing belt idler
used washers behind the tensioner pulley to get it closer to the bracket. I also had to use a trimmed down bolt to hold the sc bracket on. You’ll know it when you see it.
Also to note. This setup has been 100% solid. Still on the original belt I put on there. Many dyno pulls and some track hours on it. Zero issues with this part of my car.
Rotrex belt slip at high rpm
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