New Rotrex C38R Supercharger

jefftang04

Hope this helps

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tiller

You said you made your own sc pulleys, roughly how many mm, 90? Cuz 85mm would max it out also, we figured that to be roughly 18lbs of boost, how many lbs will you be on the dyno?

jefftang04

Hi, The new C38R has a different ratio (6:1) as compared to C38-91 (7.5:1). Hence C38R will require a smaller pulley to achieve the same impeller speed. Im currently on 82mm pulley. This will give my 80k SC rpm at 7500 engine rpm. For it to achieve 90k SC rpm, the pulley will have to be 73mm, which is a bit smaller than what rotrex recommend as the smallest allowable pulley size.

I have yet to dyno the car yet. will keep you guys updated.

Thanks

jefftang04

Hi Guys.

Latest updates. I maxed out my fuel injectors (550cc) at 400whp mainline at 5200rpm. Because of the increase in boost (7psi to 12 psi at 5200rpm) and my fuel pressure dropping to 40psi, injectors are max out. I'm going to get DW 1000cc in.

Also I'm thinking of getting a fuel return system on the car. What do you guys think. It's troublesome but I'm not sure if I can get away without one.

Thanks.

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tiller

For sure your gona need a fuel return system at 12lbs, I’d recommend cj motor sports, thats what I installed on my z, plus the aluminum fuel hat from cj also. Your gona need a fuel pump relay kit (spal kit)also if you don’t already have one.
You might even want to upgrade your fuel pump while your in there, walbro 450maybe, especially if your gona be going higher then 12lbs of boost, not sure what your using right now for a pump? Or fuel?

I used Bosch ev650cc injectors at 12lbs but iam switching to e85 this year so Id1050s now.

jefftang04

My Fuel Pump Now is DW 300, Fuel is 98 octane

Jinxx

If you go with the return system you could prolly still use the 550 injectors and tune with increased fuel pressure to cover the extra 2500 rpms... you should be around 15-16 lbs of boost at 7500 rpm

jefftang04

Looks like im going with a return system.

so CJM is the way to go?

Thanks

phunk

We made the first returns for the 370z and make frequent improvements any time we can. The kits are very comprehensive, please take a look at our website. As mentioned, the billet top hat is a very desirable upgrade as well. If you have any questions about it please email me at sales@cj-motorsports.com

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tiller

hey phunk, iam gona need the flex fuel adapter set for my hat i think, switching to e85 this season, are they in stock?

sirnixalot

That isn't even a question. I've got the top hat and the S1.SE return system, you will not be disappointed.

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2010 Sport - LS3 swap loading
2012 Frontier - BTWTuning VK56DE swap

jefftang04

Hi guys. Final numbers are out.

471whp on mainline Dyno
HP gain is about 50whp throughout from 5k rpm to 7.5k rpm. Below that is about 20 to 30whp.
14psi of boost at 7500rpm
IAT at peak is 54 DegC
DW 1000cc injectors at 85% duty cycle at peak
No fuel return.......YET........
Fuel pressure at peak is 40PSI. Too low in my books

Cheers guys.




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batboyvaj

What kind of dyno are you using? The numbers seem really low. Do you have baseline numbers from that dyno?

Spooler

That is a mainline dyno. Multiply by at least 1.1 to get dynojet numbers. Some are even off as high as 1.17. So between 518hp/551hp for dynojet numbers that you are use to.

Spooler

Get a fuel return system quick before something bad happens.