***Topgunz ROTREX C38R Supercharger Kit***

14Q60awdSPORT

In light of COBB's recent announcement, and rumors of Ecutek to follow.

Any update on different pulley sizes?
I believe the changes may prevent the evap purge solenoid from being repurposed for controlling boost.

FrankEtier

Add a Wastegate and remove the need to control boost via the EVAP purge solenoid. I made this change and it seems to be more consistent.

__________________
‘14 Topgunz Speedworks Rotrex Supercharged VR30 7AT 370Z Magma Red.
@liquid.magma

14Q60awdSPORT

That is a possible alternative people may have to do in the future if needing a tune/retune.


My setup has no issue holding 10psi low boost map or 11psi high boost map to redline at the moment. But good to know you aren’t getting boost creep on a wastegate.

cgr406

What wastegate are you using and where did you mount it? There's not much room in there!

__________________
TopGunZ Rotrex SC / CJM RFS / 1300 / Ecutek / Dynosty / F.I. TP & CBE / Z1 / Swift / SPL / Whiteline / Hotchkis / Michelin SP4

FrankEtier

I don't have the specs on the wastegate with me but it is a Tial.

Attached Images

wastegate.jpg (66.1 KB, 36 views)

__________________
‘14 Topgunz Speedworks Rotrex Supercharged VR30 7AT 370Z Magma Red.
@liquid.magma

cgr406

Thanks. I just got mine tuned @ Dynosty. I'm very happy w/ the power , but I'm definitely having the periodic power cut due to the safety factors in the tune, which Hal warned me might happen. The tune was just yesterday, so they've not yet had a chance to address it.

__________________
TopGunZ Rotrex SC / CJM RFS / 1300 / Ecutek / Dynosty / F.I. TP & CBE / Z1 / Swift / SPL / Whiteline / Hotchkis / Michelin SP4

FrankEtier

I gave the Ecutek Boost Control it's fair shake. In the end it seemed like it should work in theory but didn't really work that great in practice. Got a lot of safety cuts for overboost/boost spike on hard pulls. Since the WG installed I've had no boost spikes or safety cuts. It seems like a solid addition to the TopGunz Kit.

__________________
‘14 Topgunz Speedworks Rotrex Supercharged VR30 7AT 370Z Magma Red.
@liquid.magma

redondoaveb

Dyno results?

__________________
Fast Intentions "Stage Seb" twin turbo #098- Specialty Z/Tial-Xonarotor/CJM/Ecutek/HKS/KW/SPL/Hotchkis/Rohana/Toyo
750whp/700ft.lbs

cgr406

All I have so far is a pic of the printout they gave me. HP & TQ scales are not the same, so graph looks a bit odd. This is on 93 octane. 603 / 494.

Attached Images

DynostyDyno1(b).jpg (44.5 KB, 61 views)

__________________
TopGunZ Rotrex SC / CJM RFS / 1300 / Ecutek / Dynosty / F.I. TP & CBE / Z1 / Swift / SPL / Whiteline / Hotchkis / Michelin SP4

DrBacon

You may be better off with a fixed boost/pulley size anyways honestly. What you gain in low end torque from hitting peak boost earlier in the powerband you lose by decreased efficiency beyond that. This isn't a turbo where you are just bleeding off the excess wasted combustion anyways, you are making the engine work harder by spinning the supercharger at a certain rpm producing a specific CFM, by bleeding off the excess you are essentially wasting "work", also position of the wastegate/bypass valve matters as well, hopefully it's pre-intercooler.

14Q60awdSPORT

Yes that has always been my thought process, it does make 10lbs of boost by about 4k rpm whereas a 10psi pulley would only be making about 5.5psi at same rpm. So you’d end with same peak power but the current pulley setup will make way more power across the entire powerband.

Typically a general rule is 1psi add 6.7% more power but takes about 1.7% power away to create that psi with a supercharger. Generating 20+psi but only using 10psi isn’t very efficient but the supercharger spinning lets say 50k rpm with zero back pressure or in this case 10psi, is a lot easier than doing it against 20+ psi of back pressure so it’s not quite as inefficient as it initially seems, but still could be better optimized.

I always thought a 16psi pulley would be a good middle ground in still being able to hit about 10-11psi by 5500rpm and then flatline it only bleeding about 5psi at redline vs 13psi or so now.


I am already tuned so if I do retune it might be because of a built block and then I’ll be making max boost anyways. But who even knows timeline on if/when ecutek is following suit to COBB.