Jackson Racing Rotrex Supercharger System Info and Discussion

[OICU812]

Originally Posted by CSG Mike

It helps when development started summer 2012 :p

Hoping you guys have your kit soon, REALLY anxious to see how this does in your hands.

[ramiram1984]

Yep, has been pushed back a few days (25-26th NOV now).

[hamlet]

Also -
Oscar Jr. says they passed all the emissions testing for CARB and are waiting for the official sticker and #.

[SirBrass]

I'm not certain what a rotrex supercharger is or how it differs from other sc's, but if that dyno graph is correct, then this kit will essentially give us the simplicity of SC (no turbo exhaust manifold to deal with, etc.) but without the lack of upper band gains that sc's have, correct?

[CSG Mike]

Originally Posted by SirBrass

I'm not certain what a rotrex supercharger is or how it differs from other sc's, but if that dyno graph is correct, then this kit will essentially give us the simplicity of SC (no turbo exhaust manifold to deal with, etc.) but without the lack of upper band gains that sc's have, correct?

If you're comparing with a positive displacement supercharger, then yes.

[SirBrass]

Like I said, I'm not sure how a rotex SC is different than a centrifugal SC or a twin-screw SC, etc. JR's info on their site doesn't discuss this. But including the name in the kit seems to place some importance on the fact that this is a "rotrex supercharger" as opposed to other SC's out there. I'm just curious as to how this sets this kit apart from the others besides being another option.

[FT86Insider]

went by JR today and confirmed kit will ship in a few days ... i thought i would scoop mine up while on a mini-vacation but unfortunately not today! for those that have pre-ordered, hang in there!

[CSG Mike]

Originally Posted by SirBrass

Like I said, I'm not sure how a rotex SC is different than a centrifugal SC or a twin-screw SC, etc. JR's info on their site doesn't discuss this. But including the name in the kit seems to place some importance on the fact that this is a "rotrex supercharger" as opposed to other SC's out there. I'm just curious as to how this sets this kit apart from the others besides being another option.

A rotrex is a centrifugal supercharger like the Vortech. However, the design is different, and the impeller spins at a much higher speed. Depending on the blower, the speeds max out at 200k RPM, similar to a turbo, rather than the 50k of the Vortech. This leads to turbo levels of efficiency on the compressor side, but you still have to use engine torque to spin the supercharger.

The C30-94 used in this kit spins at approximately 100k RPM.

The end result is that for the same level of peak boost pressure, the Rotrex will be making more power with less heat, simultaneously have a fatter midrange, and begin to have noticeably more power lower in the RPM band.

This is for a S2000, but the comparisons still apply.



Red line = Rotrex (exact same C30-94) 10psi intercooled
Blue line = Positive displacement (similar to Innovate but larger) 8.5 psi intercooled
Green line = Greddy turbo (exact same turbo on the s2k!) 8 psi intercooled
Purple = Vortech 1200/1220 (exact same supercharger on the s2k!) 10 psi intercooled
Yellow = Stock

[SirBrass]

Originally Posted by CSG Mike

A rotrex is a centrifugal supercharger like the Vortech. However, the design is different, and the impeller spins at a much higher speed. Depending on the blower, the speeds max out at 200k RPM, similar to a turbo, rather than the 50k of the Vortech. This leads to turbo levels of efficiency on the compressor side, but you still have to use engine torque to spin the supercharger.

The C30-94 used in this kit spins at approximately 100k RPM.

The end result is that for the same level of peak boost pressure, the Rotrex will be making more power with less heat, simultaneously have a fatter midrange, and begin to have noticeably more power lower in the RPM band.

Sounds like the kind of FI that I was looking to add to my BRZ. Initially I was looking at the SC numbers and while I like the twin screw SC's improvement of the low end, I didn't like the expense and complexity of the AWIC setup despite its necessity, and the vortech's SC has been reported as being quite peaky among other issues. So I was considering turbo, especially considering the near lack of lag due to turbo location to the IC, intake, and intake and exhaust manifolds and the low boost being run, but I didn't like the complexity of setup (headers, up-pipe, downpipe, etc.).

This seems to be my kind of compromise.

Now I just need to begin setting up a budget and "mod schedule" for my car .

Edit: One last Q: can we use our stock airbox? I don't like the idea of sucking hot engine bay air into the intake with a bare filter. I'd want something that's closer to "CAI" than that, since I DD this thing all year, and that includes the blistering heat of Phoenix freeways in the height of summer.

[CSG Mike]

Originally Posted by SirBrass

Sounds like the kind of FI that I was looking to add to my BRZ. Initially I was looking at the SC numbers and while I like the twin screw SC's improvement of the low end, I didn't like the expense and complexity of the AWIC setup despite its necessity, and the vortech's SC has been reported as being quite peaky among other issues. So I was considering turbo, especially considering the near lack of lag due to turbo location to the IC, intake, and intake and exhaust manifolds and the low boost being run, but I didn't like the complexity of setup (headers, up-pipe, downpipe, etc.).

This seems to be my kind of compromise.

Now I just need to begin setting up a budget and "mod schedule" for my car .

Edit: One last Q: can we use our stock airbox? I don't like the idea of sucking hot engine bay air into the intake with a bare filter. I'd want something that's closer to "CAI" than that, since I DD this thing all year, and that includes the blistering heat of Phoenix freeways in the height of summer.

"CAI" doesn't matter (the difference is not significant) when FI is in the picture. When's the last time you saw a CAI on a big hp Supra?

Air gets sucked in, compressed (made really hot), cooled via intercooler, and then goes into the engine. lowering the temperature by 20 degrees won't make a significant difference when you're adding a few hundred degrees by compressing the air 10 psi over ambient. The intercooler virtually mitigates the difference you'd see by using a CAI. PV=nRT. Atmospheric air isn't an ideal gas, but it gives you an idea.

[Pscylo]

Damn that intake spot is terrible for my hood lol...right under the vent where itll get soaked when it rains.

[SirBrass]

Originally Posted by CSG Mike

"CAI" doesn't matter (the difference is not significant) when FI is in the picture. When's the last time you saw a CAI on a big hp Supra?

Air gets sucked in, compressed (made really hot), cooled via intercooler, and then goes into the engine. lowering the temperature by 20 degrees won't make a significant difference when you're adding a few hundred degrees by compressing the air 10 psi over ambient. The intercooler virtually mitigates the difference you'd see by using a CAI. PV=nRT. Atmospheric air isn't an ideal gas, but it gives you an idea.

Good point. I guess ambient temps matter more for intercooler effectiveness than it is in intake temps.

But when it's >140F off the pavement and 110F-120F ambient, I worry about temps coming into the FI system.

[Poodles]

Originally Posted by CSG Mike

"CAI" doesn't matter (the difference is not significant) when FI is in the picture. When's the last time you saw a CAI on a big hp Supra?

Air gets sucked in, compressed (made really hot), cooled via intercooler, and then goes into the engine. lowering the temperature by 20 degrees won't make a significant difference when you're adding a few hundred degrees by compressing the air 10 psi over ambient. The intercooler virtually mitigates the difference you'd see by using a CAI. PV=nRT. Atmospheric air isn't an ideal gas, but it gives you an idea.

I don't have it handy, but I've seen data logs that show that CAI is indeed a better route for FI as well. The intercooler can only take so much heat out.

The main reason you don't see a CAI on a high HP Supra is because there's no way to fit it (other than the guys that feed the turbo straight out of the hood or from where the front headlight would be)

[imom]

Hi CSG Mike, that blue line has about 75 more lbs of torque on the low end... what's the tradeoff of an innovate type supercharger versus the Rotrex? Perhaps the KW redline is more suitable for track and corners, but the blue line seems more fun for street low end power...

Side note...wish Jackson would reply to my previous post and comment more often now that SEMA is over...like more info.