Supercharger Discussion For all you misguided souls.
Sponsored by:
Sponsored by:

Rotrex belt slip at high rpm

 
Old 03-31-2019, 12:55 PM
  #21  
Junior Member
 
Join Date: Dec 2010
Posts: 491
Total Cats: 10
Default

Twibs,

I'm wicked confused. You say this...

Originally Posted by Twibs415 View Post
the spm supercharger pulley is not the same alignment with two more ribs out front. Itís 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
But also this...

Originally Posted by Twibs415 View Post
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.
I can't find spm supercharger pulleys in the google machine. Did you replace the pulley on the Rotrex? Mine already has a six rib pulley. What I need is an overlay for the crank pulley. If your Rotrex came with a four-rib pulley that lined up with the stock crank pulley, how were you able to use a new six-rib supercharger pulley that had an extra rib on each end without spacing it out at least one rib's thickness from the Rotrex?

You used an overlay for your crank pulley. Doesn't that mean you should have used a larger pulley for the Rotrex as well? I thought 80mm with the stock crank pulley would take the Rotrex to its max rpm of 120,000, so a larger overlay would overspin the Rotrex when you get up into the higher engine rpms.

I did check out your IG page. Beautiful car.

Thanks,
poormxdad is offline  
Old 03-31-2019, 02:38 PM
  #22  
Senior Member
Thread Starter
iTrader: (6)
 
Join Date: Feb 2011
Posts: 538
Total Cats: 64
Default

The spm pulley is itís own beast with its own issues. And things with it werenít as advertised. I would disregard anything you read about it because I donít think there were even a handful of them made.

Iirc all the rotrex pulleys come in 6-8 rib. There no issues with this side of the equation. Figure out what crank pulley diameter youíll be running and then give kraftwerks a call and They can set you up.
Twibs415 is offline  
Old 04-01-2019, 05:55 AM
  #23  
Junior Member
 
Join Date: May 2015
Location: Portugal
Posts: 83
Total Cats: 16
Default

BTW poormxdad , the 75mm rotrex pulley will put the c30-74 just under 120k RPM at 7000rpm with the stock miata BP pulley, not the 80mm one.
lbatalha is offline  
Old 04-04-2019, 04:53 PM
  #24  
Junior Member
 
Join Date: Dec 2010
Posts: 491
Total Cats: 10
Default

Originally Posted by lbatalha View Post
BTW, the 75mm rotrex pulley will put the c30-74 just under 120k RPM at 7000rpm with the stock miata BP pulley, not the 80mm one.
Irregardfull, that doesn't mean he's not overspinning the Rotrex. I should be at about 10psi with the OEM crank pulley and 80mm s/c pulley, but I've got some belt slippage as well. If he's got an overlay, he should be making more than 10 psi.

Twibs, did you see an increase in boost when you got it all sorted out?
poormxdad is offline  
Old 04-07-2019, 01:22 PM
  #25  
Senior Member
Thread Starter
iTrader: (6)
 
Join Date: Feb 2011
Posts: 538
Total Cats: 64
Default

If I remember right I was slipping about .5 of a psi before the belt broke on the dyno.

My before the overlay and after had similar max blower rpm. So no measureable difference except not breaking belts.

I did see an increase In boost with my bigger exhaust.
Twibs415 is offline  
Old 04-07-2019, 04:15 PM
  #26  
Junior Member
 
Join Date: May 2015
Location: Portugal
Posts: 83
Total Cats: 16
Default

poormxdad if you dont have P/S, it might be worth looking into an ATI Damper, they have 6 rib support so they might line up correctly with the rotrex (since they align with the stock PS, and just have more rib space forward, its likely you can just bolt it on and add a 6 rib belt, and be done with it)

https://www.flyinmiata.com/ati-dampe...-kit-36-2.html

Probably better to talk with FM about it to confirm though.
lbatalha is offline  
Old 05-23-2019, 11:13 AM
  #27  
Junior Member
 
Join Date: May 2015
Location: Portugal
Posts: 83
Total Cats: 16
Default

Update: Installed 75mm pulley and am using a very cheap weird brand belt at the moment while waiting for the Gates RPM belt. The current belt is also a tiny bit too long as my static tensioner is almost touching the P/S pulley.

I have not seen any slip yet, even with this garbage belt not being tensioned that much (auto-tensioner is a bit away from the optimal position)

I have measured 0.84 bar (12psi) @ 7200rpm with MAT of 21C (70f). With a MAT of 38C (100f) with ambient temp of 33C (91f) I was seeing 0.75bar (10.8psi) @ 7200rpm

The boost the 85mm pulley was giving me at 7200rpm (0.64bar) I am now making at 6000rpm

With the new belt I should have a bit of slip margin hopefully. I have yet to track the car in this spec so slippage during consistent hard conditions is unknown as of yet.
lbatalha is offline  
Old 05-23-2019, 01:16 PM
  #28  
Junior Member
 
Join Date: Dec 2010
Posts: 491
Total Cats: 10
Default

I installed the Elantra timing belt idler. That was a great find. It gave me a little more tightening adjustment with the 40457 belt. It's 60mm. 62mm or so would be even better.

Have any of you found a significantly better tensioner assembly than what comes with the kit(s)?

Thanks,
poormxdad is offline  
Old 05-23-2019, 01:23 PM
  #29  
Junior Member
 
Join Date: Jul 2015
Posts: 463
Total Cats: 31
Default

Audi ones *could* work; need to get my hands on one to measure how much load it can apply.
HarryB is offline  
Old 05-24-2019, 05:17 AM
  #30  
Junior Member
 
Join Date: May 2015
Location: Portugal
Posts: 83
Total Cats: 16
Default

Originally Posted by poormxdad View Post
I installed the Elantra timing belt idler. That was a great find. It gave me a little more tightening adjustment with the 40457 belt. It's 60mm. 62mm or so would be even better.

Have any of you found a significantly better tensioner assembly than what comes with the kit(s)?

Thanks,
Can you give us a part# for this? does it fit perfectly in the kraftwerks bracket?

Also for future reference, and everyone on the internet trying to figure this out:
The part numbers for the stuff that comes with the kraftwerks kit, as best as I can tell
Auto-tensioner - Gates 38164
Tensioner Idler - Dayco 89003

The auto-tensioner looks to have the same mounting pattern, but the pulley wheel is obviously different, so I dont know if this one has more tension than the one I have.
lbatalha is offline  
Old 05-24-2019, 08:10 AM
  #31  
Junior Member
 
Join Date: Jul 2015
Posts: 463
Total Cats: 31
Default

The part numbers are indeed correct; the Gates autotensioner gives about 450NM of torque. The Audi one I have been mentioning as a possible replacement is from an Audi A4 2.0 2009-2011, part no. 06H903133F, which I need to measure in terms of load that it can apply.
HarryB is offline  
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
thumpetto007
Miata parts for sale/trade
19
08-16-2016 06:12 PM
gsyk59
Supercharger Discussion
2
02-02-2016 09:46 AM
jrmotorsports55
Miata parts for sale/trade
11
09-08-2014 08:15 PM
falcon
Supercharger Discussion
15
06-01-2011 10:09 PM
D.dutton9512
Supercharger Discussion
4
01-05-2011 11:54 PM


Thread Tools
Search this Thread
Quick Reply: Rotrex belt slip at high rpm


Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.