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Back from the dead! After two years of mishaps and delays from the mechanics, the motor is finally built and ready to be put inside the car! Stay tuned!
After lots of experimentation, a 85mm pulley was fit to the Rotrex, driven from a 156mm crank pulley and we got 500hp at the crank. It seems that the Rotrex behaves quite differently from other centrifugal superchargers in the market and the efficiency map provided needs to be interpreted in a quite different manner.
Rotrex C38-91, spun at ~12800 rpm at the pulley, 0.8bar max boost, 11.5 AFR, 8.8:1 compression, stock ignition timing
Ok, so after a few months waiting and repairing, the results are: +0.35bar boost, +70bhp, +80Nm. Boost was a bit less than 1.2bar spinning the C38R at full speed. Some things worth noting are:
- Despite the 8.8:1 compression, regular gas dictated a -10 decrease of ignition advance after 5500rpm, going to 16deg of value. We decided to use 100oct gas in order to go to 20deg
- With 6ribs belt, there was slippage after 4500rpm. We went with 8rib belt which had no slip. However, we misdiagnosed belt slippage near red line due to the fact that stock ECU has soft rev limiting.
Hope this will give you insight as to whether you will be using a C38R or not...
Last edited by goatofrafin; May 1, 2019 at 11:40 PM.
Reason: Wrong ignition advance values and belt slippage diagnosis
Great to see that you are still going at it and great job on the result. Any other plans coming for it or enjoying it for a while?
Well, at some point I am thinking of VVT tuning. I had a V-Manage but for some reason, when engaged, idle was going to about 950rpm so I removed it. Second thing is my JWT clutch, it has started getting noisy and I might go to a twin clutch system. Other than that, I have no other plans for upgrades!
Originally Posted by 350z-Helsinki
This is supercool stuff and great numbers. If I only had the skills to do what you do this would have been a nice approach to supercharging!
Thanks! Well the numbers should be much higher according to Rotrex but for some reason, they are not... Other than that, the bracket from Auto-Gruppen is a perfect fit but having the supercharger so low is both a good and a bad thing; the good thing is that it always sucks fresh cold air and the bad thing is that no proper air filter can fit and there is an increased danger of sucking water.
Last edited by goatofrafin; May 1, 2019 at 07:01 AM.
i fodn your post on google because i'am searching for c38r expieriences.
i'm driving an Opel Calibra 4x4 V6 with 3,0 litres and an c38-81. at 520HP and 1,3bar with "only" 12300rpm at the pulley.
I was surprised u only reach 500HP even with overreving the c38-91.
I think the reason is your intercooler.
I tried several intercooler by myself on my car. I was able to increase my boost from 0,9bar to 1,3bar only by changeing the intercooler. First i started with a cheap 600x180x60 bar and plate. Then i tried a tube and fin and got 1,1bar. At the moment i have a huge 600x300x90 Bar and plate Treadstone intercooler with 1,3bar boost.
I think, if u replace your intercooler with another one which has its entrance and exit on the other side and as big as possible u could increase your power-output and boost by far.
A friend of mine has the same rotrex-setup and placed a intercooler like u in his car, he got only 0,6 bar of boost and about 360hp.
I dont want to be a smartass. I just thought it could be interesting for u.
i fodn your post on google because i'am searching for c38r expieriences.
i'm driving an Opel Calibra 4x4 V6 with 3,0 litres and an c38-81. at 520HP and 1,3bar with "only" 12300rpm at the pulley.
I was surprised u only reach 500HP even with overreving the c38-91.
I think the reason is your intercooler.
I tried several intercooler by myself on my car. I was able to increase my boost from 0,9bar to 1,3bar only by changeing the intercooler. First i started with a cheap 600x180x60 bar and plate. Then i tried a tube and fin and got 1,1bar. At the moment i have a huge 600x300x90 Bar and plate Treadstone intercooler with 1,3bar boost.
I think, if u replace your intercooler with another one which has its entrance and exit on the other side and as big as possible u could increase your power-output and boost by far.
A friend of mine has the same rotrex-setup and placed a intercooler like u in his car, he got only 0,6 bar of boost and about 360hp.
I dont want to be a smartass. I just thought it could be interesting for u.
Best Regards Thomas
There must be a pressure loss situation going on which would be one good way to explain what you experienced.
Is this bracket currently in production to adapt the rotrex to the VQ engine?
I tried several intercooler by myself on my car. I was able to increase my boost from 0,9bar to 1,3bar only by changeing the intercooler. First i started with a cheap 600x180x60 bar and plate. Then i tried a tube and fin and got 1,1bar. At the moment i have a huge 600x300x90 Bar and plate Treadstone intercooler with 1,3bar boost.
I think, if u replace your intercooler with another one which has its entrance and exit on the other side and as big as possible u could increase your power-output and boost by far.
A friend of mine has the same rotrex-setup and placed a intercooler like u in his car, he got only 0,6 bar of boost and about 360hp.
I dont want to be a smartass. I just thought it could be interesting for u.
Best Regards Thomas
What can I say... First of all, thanks for sharing your experience. To be honest, I am not COMPLETELY satisfied by my power output, considering the promises from Rotrex. My explanation is that the traction drive has variable efficiency and that is where the problems start.
Moreover, if there is no leakage, the air will get in somehow. I can understand pressure loss but not air loss if the whole plumbing is air tight. Do you have a pre/post Rotrex dyno pull? What dyno are you using? Please share your dyno charts!
P.S.: At wikipedia, the V6 Calibra is 2.5 liters. What is your model and how much HP was it making NA? Did you swap with the X30XE making 208bhp?
Last edited by goatofrafin; Jun 1, 2019 at 08:52 AM.
This was my Dyno last year, with the 1,1bar setting, i dont know which dyno-brand ist was. just wanted to see some numbers
The Calibra was a naked 2.0Turbo 4x4 frame. But i already have a 2.0T calibra, so i decided to put in the X30XE 3.0V6 from the Omega B with stock 211HP. I used the intake manifold from Z32SE Vectra C and some Headers build by my own. I had around 230HP naturally aspirated.
I reinforced the Engine with Woessner Pistons (8,5:1) and Pauter X-Shaft Conrods and some other modifications.
I'm pretty satisfied with the performance, did some comparisons at the trafficlight and its really quick. Other cars with the same Power are slower. 2 Weeks ago i was on a carmeet with 1/8 mile racing. I had a race vs. a Calibra 2.0T with 400HP and racing-4x4 (50:50 distribution fully locked). I lost the start but mananged to win this race (other car was even 250kg lighter).
A friend of mine has the same rotrex-setup and placed a intercooler like u in his car, he got only 0,6 bar of boost and about 360hp.
My friend has 0,8Bar before he put in the intercooler with a 110mm pulley, now he has 0,6bar with a 90mm pulley. that shows pretty well how much pressureloss u have with a bad intercooler. (ofc. lower IAT results in lower pressure but not that much)
Last edited by Lumberjack2302; Jun 17, 2019 at 10:45 AM.
