Replacement Rotrex Supercharger for the GTM Stage 1 kit
 

Can anyone confirm with certainty that the GTM Stage 1 kit uses the Rotrex C38-81 supercharger head? I am fairly certain this is the correct supercharger.

My car was in the shop for a yearly Rotrex service (unicorn blood based traction fluid and filter) and they diagnosed what I thought was a faulty idler as a rattle/grinding noise with the supercharger itself. When the tech drained the Rotrex filter into a container it was completely obvious the fluid was full of metal remnants.

So I am weighing replacing the supercharger versus returning the car back to stock. Sorry guys but going another FI route is not in the cards for me right now. I am a little leery going the replacement route as the original lasted 34 months and 27k miles with no track time and no auto-x. This car was only street driven and it is my DD.

From the site for a Stage 1 SC:



The GTM Supercharger kit has two different Rotrex compressors to chose from: the C38-81 trim and the C38-91. Combined with our custom compressor housing we will offer three different stages .

Stage zero up to 450 HP (CARB approval in progress)
Stage one up to 500 HP
Stage two up to 550 HP

Also from the site:

We are pleased to announce the GTM Stage 1.5 Supercharger Kit for the 370Z. The Stage 1.5 uses the same supercharger head unit as our Stage 1 Kit (the Rotrex C38-81) with the intake system of our Stage 2 Kit

How much do they want to rebuild the unit?

Thanks for the reply. I saw that on GTM's page. I still need to know the correct trim, C38-81 or C38-91.

From what I find online, the units are not rebuildable. There is an online vendor who advertises rebuilds but if I stay FI, I will just purchase a new unit.

My money is on the 81, just call GTM. It's hard to believe the Rotrex isn't rebuildable.

ETA...Sure enough, went on Rotrex's website and they can't be rebuilt. Score one more for Turbo set-ups

Does rotrex do a core credit on a new one? One would think there is a serial number on that bitch somwhere

Edit: googled it gonna throw this in here in case you need it Rotrex instalation guidlines

lol

The stage one is a C38-81, Stage 1.5- C38-81 with larger housing, and stage 2- C38-91. Sorry to hear about your troubles with your unit. I'll see if I can find the only company I know of that rebuilds Rotrex Superchargers. Even though Rotrex says the unit cannot be built, It can be done for a lot less than buying a new one.

Here is the website. I just emailed this company to see if they are still rebuilding C38 units. I Hope you decide to rebuild or upgrade your unit vs going back to stock. I suggest going with the C38-91 if you decide to buy new. More room to grow later, and you could go down on the boost to make similar numbers as you were making. Good luck.

Supercharger Rebuilds » Rotrex Repair C38, C30, C15, SP30

If stage II is really the C38-91 then I'm pretty sure you can't upgrade to that one without a new motor mount. GTM included it with stage II kit. They might sell you one but who knows when you would get it.

Yes, You are right. I forgot to mention that. I went from a stage 1 to 1.5 SC and had install the mount and buy the new air filter relocation kit. Looks like the best bet is for a rebuild or new C38.

When you upgraded to the 1.5 it is a different rotrex unit correct?
Do you by chance happen to know if the larger unit fits without requiring GTM motor mounts and filter relocation kit? I was always curious if a stage 1 owner could bump up one size without actually having to redo a bunch of items and then just throw on a smaller pulley and be done.

Mainly because I do not like the 1.5/2 filter location.

No my Rotrex 1.5 upgrade is the same stg1 sc C38-81 with just a larger housing. The larger Rotrex unit will likely not fit with the stg1 configuration. You could still always use a smaller pulley for more power on your current setup.

That was my plan, looking over the charts of the units at 8psi it is in the lower 50% so plenty of room to drop down a pulley size and bump up the psi to 10-11. Plus my other upgrade idea with that is e85 to squeeze out a little more that 93 octane lacks.

OK -81 is stage 1 and 1.5. You need the GTM kit to upgrade
-91 is stage 2 only

Next you can get a new unit from other non GTM source for $1800.

Last I think your unit may be under warranty contact rotrex direct to find out.

PM me if you want more data

Where did you find a Rotrex sc for $1800? Please do tell:) I believe the Rotrex sc's carry a 12 month warranty. I believe the op has owned his kit longer.

Has anyone with a GTM SC tuned with E85? I'm curious as to what numbers that would achieve.

Yeah....I want to know also. May need one soon. :shakes head:

Why do you think you might need one soon? did they F up your supercharger oil system too? It has a 1 year warranty, man get out of your funk and enjoy your car.

Replacing the BPV on Monday to see if that's the problem. Can't enjoy sh!t right now.

Is there a company besides turbo smart that makes a bpv seems like a lot of guys have had issues with that design. I know their race port valves kick *** but it seems like the cheaper valves(which the BPV is based on) have real problems with sticking.

Edit: the gtm kit is blow through so you could always switch to a race port bov if it keeps doing this, since it seems the tials have had issues lately as well.

My Tial is working well so far. I'll give an update at the end of summer of how it's holding up.

They used to be great but then what are basically rumors about seals and things started popping up, maybe they fixed it or it was never an issue? I wonder how their Q series bypass valves would hold up. apparently perrin makes one also but both of those are near double the price of the turbosmart

A lot of good reviews about the Synapse blow off valve, it's inexpensive too.

I'm sure dirt ends up getting inside the horn of the blow off valve while driving and ends up getting stuck to the piston which in turn scores the sides and it eventually seizes.

This is probably why the recommendation for maintenance every 6 months. I ended up twisting the valve 90 degrees, facing the passenger side. 2 years, no issues so far (knock on wood).

oh yeah there is no question its caused it's caused by dirt getting in the valve and scoring it up, seems like the cheaper turbo smarts may be a little too sensitive to it though. Might have been a good aplication for something like a teflon coating.

Lol this is what I did to mine for now

http://img.tapatalk.com/d/14/05/12/ybuqu8ud.jpg

ahah not exactly what I meant in the other thread of putting a filter over it but hey if it works lol

Hhaha yeah didn't get a chance to order a crankcase filter from k&n so this will do for now lmao!

You have PM

how much do you want for your kit?

You have a PM.