Jackson Racing SC Kit - C30-94 Rotrex Supercharger High Boost Pulley Release

[dj2020]

Originally Posted by CSG Mike

This is something CSG and Shawn have experience with; it's been around for years, even on this platform

Do tell us more! I'm wondering if I should go a pure tune route through Church to make 91 safer or should I explore this wastegate/boost control option.

[xsnapshot]

Just out of curiosity.....is the JRSC maxed out with this smaller pulley? What % of capacity is it running? Just wondering if one could go another tiny step smaller. I think this is a 100mm pulley right? And standard is 110mm? So maybe a 95mm? Just curious.

[CSG Mike]

Originally Posted by xsnapshot

Just out of curiosity.....is the JRSC maxed out with this smaller pulley? What % of capacity is it running? Just wondering if one could go another tiny step smaller. I think this is a 100mm pulley right? And standard is 110mm? So maybe a 95mm? Just curious.

That depends on RPM for your given redline. At 7400, it is at 97% with the 100mm pulley.

[xsnapshot]

Originally Posted by CSG Mike

That depends on RPM for your given redline. At 7400, it is at 97% with the 100mm pulley.

Let's say you left redline at 7400. What would a 95mm pulley put the blower at? My guess is over 100%, but by how much would be the question.

[Jackson Racing]

Originally Posted by dj2020

I'm thinking of doing this soon and Shawn Church says it's no problem for him doing a 91/e85 flex fuel tune. I'll probably run e85 full time but he says he can make it safe when on 91 for road trips.

He also said something interesting that I never thought of, which is to add a wastegate to the intake tube to limit your boost to 9psi on the HBP. That would be another way of making the HBP safer for 91 octane. I did some research and it looks like a lot of domestic muscle cars on centrifugal SCs will run a higher boost pulley but limit the actual boost at the top end with a wastegate. That way you'll have higher boost levels at a lower rpm. Just thought I'd share and have a discussion.

Yeah, we have done this on different applications. There are additional components, cost, and complication associated with it. But yes, it works.

If you are planning to run E85 most of the time, it really would never be used. Also, guys are running around with 91/E85 flexfuel without the wastage system. We don't recommend using 91 octane with the high boost pulley because the benefit of the additional boost is taken away by the amount of timing you need to pull out.

[CSG Mike]

Originally Posted by xsnapshot

Let's say you left redline at 7400. What would a 95mm pulley put the blower at? My guess is over 100%, but by how much would be the question.

About 102%.

But, you need to leave overhead for slight overrevs. Don't do it. You *will* destroy your supercharger.

[DaiTT500]

Has any testing be done with supercharger efficiency past stock redline with built heads and upgraded valvetrain?

[CSG Mike]

Originally Posted by DaiTT500

Has any testing be done with supercharger efficiency past stock redline with built heads and upgraded valvetrain?

That's more of an engine efficiency question, than supercharger.

If the engine is free flowing, then the SC will keep reving.

Example: S2ks rev higher, so the supercharger's pulley ratio (vs crank) is higher to spin it "slower per rev". But, up at 9000 (engine) RPMs, it's singing along just as happily.

[dj2020]

Couldn't find it on this thread: what are the torque specs for the supercharger pulley bolts?

Also, any pros and cons using a 2.5 vs 3.0 bar MAP sensor on this type of set up?

[xsnapshot]

Originally Posted by CSG Mike

About 102%.

But, you need to leave overhead for slight overrevs. Don't do it. You *will* destroy your supercharger.

Oh I'll never need more power than the highboost pulley provides

I was just curious as to the theoretical max of this supercharger. Thanks for the info though!

[CSG Mike]

Originally Posted by dj2020

Couldn't find it on this thread: what are the torque specs for the supercharger pulley bolts?

Also, any pros and cons using a 2.5 vs 3.0 bar MAP sensor on this type of set up?

locktite red and... something low.

lower map sensor gives you more resolution; higher bar map sensor gives you more theoretical overhead.

Both will be fine for a JRSC.

[dj2020]

Originally Posted by CSG Mike

locktite red and... something low.



lower map sensor gives you more resolution; higher bar map sensor gives you more theoretical overhead.



Both will be fine for a JRSC.

Googled and got these specs:

http://www.rotrex.com/media/7df7470f...30%20Range_pdf

Mounting torque pulley bolt: looks like it's M10 bolts, torqued to 37 ft-lb. Much higher than the oil banjo and and bracket mounting bolts. Anyone, please correct me if I'm wrong because it does seem awfully high for such small bolts.

Also, any brand map sensor is okay? All similar quality?

[CSG Mike]

Originally Posted by dj2020

Googled and got these specs:

http://www.rotrex.com/media/7df7470f...30%20Range_pdf

Mounting torque pulley bolt: looks like it's M10 bolts, torqued to 37 ft-lb. Much higher than the oil banjo and and bracket mounting bolts. Anyone, please correct me if I'm wrong because it does seem awfully high for such small bolts.

Also, any brand map sensor is okay? All similar quality?

Jackson Racing also offers a MAP sensor now; PM @CounterSpace Garage to get one.

[CSG Mike]

Originally Posted by dj2020

Googled and got these specs:

http://www.rotrex.com/media/7df7470f...30%20Range_pdf

Mounting torque pulley bolt: looks like it's M10 bolts, torqued to 37 ft-lb. Much higher than the oil banjo and and bracket mounting bolts. Anyone, please correct me if I'm wrong because it does seem awfully high for such small bolts.

Also, any brand map sensor is okay? All similar quality?

Torque to 9ft lbs, per the Installation Manual from JR.