New Rotrex C38R Supercharger

Originally Posted by jefftang04

Hi All,

I just recieved My C38R unit. Will be replacing the C38-81 on my GTM Stage 1.5 kit in February.

Currently I'm doing 450whp and 380lbft at 10PSI. Will update with results once the system is running.

a few points:
1) The inlet is 3" as compared to 2.5' for the C38-81
2) From my calculations current C38-81 is drawing 80+ HP at peak (85mm pulley)
3) If you were to run the C38R at peak rpm it will draw up to 130hp. This will affect the pulley system requirements. currently my system is running 8PK instead of the
stock 7pk. Still, it barely meets the needs of 130hp. i believe 10pk would be needed to maintain the same belt change interval.
4) The C38R (7:1) has a different gear ratio as compared to the C38-81 (6:1) ratio so the pulley size will definitely change.
5) Because of the pressure ratio (assuming rest of the system is the same) IAT will increase by about 25degC so upgrading IC might be unavoidable.

Thanks all

Originally Posted by tiller

Good to hear there actually getting out to customers, have they said when there gona be available for anyone to purchase?I’ve been waiting on info for awhile as iam thinking about upgrading my rotrex on my gtm stage 2 kit.

What was the final cost if you don’t mind me asking? I believe the c38-91 that is on my car is already 3” inlet.

Keep me posted thanks

Originally Posted by Jinxx

The gtm stage 2 kit has a 3 inch pipe with a 4 inch velocity stack

Originally Posted by tiller

Yes your right.

Where’s the rest of the people that were on the pre order list, the suspense is killing me to find out more about this unit.

Originally Posted by Jinxx

I kinda wish I still had my GTM supercharger kit ...but I sold the 2015 nismo..and sold the kit off it ....still pushing the 2017 nismo with the turbo tho ....having 2 Zs was with both kits made it hard to choose which to keep lol

Originally Posted by tiller

Ya my z with that sc kit on it is a great all around car, converting it to e85 this year, but I really want to see how this c38r performs, I think at 17lbs of boost on a Mildly built motor on e85 should put down some good usable numbers.

Originally Posted by tiller

Good to hear there actually getting out to customers, have they said when there gona be available for anyone to purchase?I’ve been waiting on info for awhile as iam thinking about upgrading my rotrex on my gtm stage 2 kit.

What was the final cost if you don’t mind me asking? I believe the c38-91 that is on my car is already 3” inlet.

Keep me posted thanks

Originally Posted by jefftang04

It's almost 3k Euros for the complete kit with coolers reservior plumbing etc.

Sorry it is 3.5" not 3". I corrected my post.

Thanks

Originally Posted by tiller

Ya I was told the c38r will work on existing sc kits out there, I already have the c38-91 installed on my z, so I just need the pump itself, keep us posted on what changes you had to make and the performance of this unit, lbs of boost etc, this pump could determine wether I sell my kit or not, if I can get 17lbs out of this unit that be perfect.

Originally Posted by jefftang04

The charge cooler definitely needs an upgrade. The gtm one most prob will be to limited.

Next would be the serpentine belt. Are you still on stock 7pk? Min it should be 8pk and even that's a stretch. 10pk would be perfect.

Originally Posted by tiller

Have you found a 10pk that fits your gtm? Doubt there is one, I haven’t had any issue so far with the belt on my kit with c38-91, and it’s maxed out ,but I always keep a spare with me.

Originally Posted by jefftang04

I'm currently on 8pk. Had to custom most of the pulleys. But it was worth it as the belt is able to last much longer now.