Kraftwerks Rotrex Supercharger Discussion - Page 39 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

gmsii · 12-19-2013, 05:07 PM

Quote:

Originally Posted by CSG Mike

I may have missed this, but can anyone post the diameter of the pulley on the Rotrex? @gmsii @KraftWerks

you are asking the wrong question.

CSG Mike · 12-19-2013, 06:15 PM

Quote:

Originally Posted by gmsii

you are asking the wrong question.

I'm not understanding... I just want to know the diameter of the default cogged pulley on the supercharger is.

Will you be offering alternate pulleys for the current C30-94 setup?

Calum · 12-19-2013, 06:21 PM

Quote:

Originally Posted by CSG Mike

I'm not understanding... I just want to know the diameter of the default cogged pulley on the supercharger is.

Will you be offering alternate pulleys for the current C30-94 setup?

Let me see if I can translate douche to english for you. What I think he's getting at is that you would have to know the number of teeth on both pulleys to know what the actual speed ratio is.

I've been thinking about asking the same question though, so, @gmsii how many teeth are on both gears. Or if you feel like saving us the time of doing the math, what did you end up with for a supercharger impeller rpm at 7450 engine crankshaft rpm?

And Mike, do you know the supercharger impeller rpm for the JR kit.

Ralph Spoilsport · 12-19-2013, 07:01 PM

Quote:

Originally Posted by CSG Mike

I'm not understanding... I just want to know the diameter of the default cogged pulley on the supercharger is.

Will you be offering alternate pulleys for the current C30-94 setup?

Looking at DA's pics, I think I see 30T(-75mm?) on the small cog and 40T on the big one.

CSG Mike · 12-19-2013, 07:10 PM

Oh, I forgot the belt system is independent. I suppose I'll be counting the teeth. Be back in a minute.

*edit*

Okay, I can't see all the teeth, and I don't have a kit on hand to do any math.
@gmsii: What RPM is the supercharger spinning at redline with the included pulley?

CSG Mike · 12-19-2013, 07:17 PM

Quote:

Originally Posted by Calum

And Mike, do you know the supercharger impeller rpm for the JR kit.

About 87k. The blower is rated for 100k. Impeller RPM is about 9100 at 7400 engine RPM on the Jackson Racing kit. I'm trying to figure out what it is on the Kraftwerks kit.

cobrabyte · 12-19-2013, 07:20 PM

Being as though they recommend a redline of 7800 RPM, that may tell you what the rotational speed is at that point. Dunno if they've put some wiggle room in there. I have no clue.

cobrabyte · 12-19-2013, 07:23 PM

Perhaps the parts sheet has what you need:

CSG Mike · 12-19-2013, 07:33 PM

Crank pulley 100mm, Rotrex pulley 75mm. Got it. Not sure why it was so difficult for them to just tell me that... brb after I do some quick math.

3 rotations on crank = 4 rotations on Rotrex. Essentially, 1.33 multiplication. Teeth counts confirm, 30 vs 40.

7800 RPM redline * 40 teeth / 30 teeth = 10400 impeller RPM.

The Rotrex C30-94 is spec'ed out for 10500 impeller RPM.

Quote:

Originally Posted by gmsii

the blower is set up to hit 10.2psi with a max engine RPM of 7800.
we have a smaller pulley set-up where the engine redline is set for 7300rpm engine that makes about 13psi boost and about 15whp more in the midrange and 30whp more peak

Essentially, the blower is maxed out with the Kraftwerks kit, at the 7800 RPM that Kraftwerks recommends (per the post above). I'm guessing the 7300RPM redline pulley is a 38 tooth pulley/71mm pulley??

gmsii · 12-19-2013, 07:45 PM

Quote:

Originally Posted by CSG Mike

Crank pulley 100mm, Rotrex pulley 75mm. Got it. Not sure why it was so difficult for them to just tell me that... brb after I do some quick math.

3 rotations on crank = 4 rotations on Rotrex. Essentially, 1.33 multiplication. Teeth counts confirm, 30 vs 40.

7800 RPM redline * 40 teeth / 30 teeth = 10400 impeller RPM.

The Rotrex C30-94 is spec'ed out for 10500 impeller RPM.

Essentially, the blower is maxed out with the Kraftwerks kit, at the 7800 RPM that Kraftwerks recommends (per the post above).

wouldn't have been hard to tell you bro....just wanted peeps to slow down and think about things a bit...no ****ishness intended. sorry

yes, blower is close to being maxed out at 7800rpm, but kit performance is not maxed out by any means....we will be offering a pulley upgrade shortly that will change the power delivery quite dramatically

OjiGeorge · 12-19-2013, 07:46 PM

Would it make sense to wait for C38 kit for those of us that want higher power numbers on stock internals? Planning on WMI w 93 octane and upgraded fuel system.

gmsii · 12-19-2013, 07:49 PM

Quote:

Originally Posted by OjiGeorge

Would it make sense to wait for C38 kit for those of us that want higher power numbers on stock internals? Planning on WMI w 93 octane and upgraded fuel system.

we'll be releasing preliminary test data soon enough for you to make that determination...keep an eye out

CSG Mike · 12-19-2013, 07:50 PM

Quote:

Originally Posted by OjiGeorge

Would it make sense to wait for C38 kit for those of us that want higher power numbers on stock internals? Planning on WMI w 93 octane and upgraded fuel system.

Only if you have the supporting mods for that kind of output (Transmission, axles, etc). The base kit is plenty of power...

OjiGeorge · 12-19-2013, 08:28 PM

Can't seem to stop spending money on the car, so the supporting mods are sure to follow. ATM trying to reduce the risk of buying a system that will not be able to keep up with future mods. It will likely come down to the the KW or the AVO kit. Both because Drift Office is relatively close, and has experience with tuning both of these kits.

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12-19-2013, 07:10 PM	#537
CSG Mike Join Date: Jul 2012 Drives: S2000 CR Location: Orange County Posts: 14,516 Thanks: 8,909 Thanked 14,161 Times in 6,826 Posts Mentioned: 966 Post(s) Tagged: 14 Thread(s)	Oh, I forgot the belt system is independent. I suppose I'll be counting the teeth. Be back in a minute. edit Okay, I can't see all the teeth, and I don't have a kit on hand to do any math. @gmsii: What RPM is the supercharger spinning at redline with the included pulley?

12-19-2013, 07:46 PM	#543
OjiGeorge Senior Member Join Date: Jul 2012 Drives: White 2013 FRS Location: Langley, BC Posts: 450 Thanks: 441 Thanked 146 Times in 92 Posts Mentioned: 6 Post(s) Tagged: 0 Thread(s)	Would it make sense to wait for C38 kit for those of us that want higher power numbers on stock internals? Planning on WMI w 93 octane and upgraded fuel system.

12-19-2013, 08:28 PM	#546
OjiGeorge Senior Member Join Date: Jul 2012 Drives: White 2013 FRS Location: Langley, BC Posts: 450 Thanks: 441 Thanked 146 Times in 92 Posts Mentioned: 6 Post(s) Tagged: 0 Thread(s)	Can't seem to stop spending money on the car, so the supporting mods are sure to follow. ATM trying to reduce the risk of buying a system that will not be able to keep up with future mods. It will likely come down to the the KW or the AVO kit. Both because Drift Office is relatively close, and has experience with tuning both of these kits.

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