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

[xsnapshot]

Originally Posted by PandaSPUR

Just been poking around doing research on different FI systems and this caught my eye. I'm wondering, is it possible to add a boost controller to this system? So I can just go straight for the HBP with all supporting mods, but turn it down until I feel I'm ready. Basically giving myself some growing room without having to go back to the tuner or swapping the pulleys myself.

Again, its a pretty newb question. I searched around but didnt find anything about adding a controller to SC systems. (Probably cause they dont usually put out enough boost to warrant a controller I assume).

I am doing something like this with my car and a Moto-East tune.

It's not a boost controller, but power IS reduced up top via reduced ignition advance. (maybe other things as well like valve overlap or something...Mike would have to chime in on that).

The high boost pulley does provide a little more down low and in the midrange, but I was wary of how much power it puts out up top. It's all about how much torque the motor is putting out. So if you can reduce the peak cylinder pressures and torque via reduced ignition advance or cam timing, 12 psi can be safe up top as well.

[sw20kosh]

Originally Posted by PandaSPUR

Just been poking around doing research on different FI systems and this caught my eye. I'm wondering, is it possible to add a boost controller to this system? So I can just go straight for the HBP with all supporting mods, but turn it down until I feel I'm ready. Basically giving myself some growing room without having to go back to the tuner or swapping the pulleys myself.

Again, its a pretty newb question. I searched around but didnt find anything about adding a controller to SC systems. (Probably cause they dont usually put out enough boost to warrant a controller I assume).

Super chargers are mechanically driven and thus produce a set amount of boost at any given rpm. You cannot control it like a turbo...

Ways around that limitation is to choke the intake on the supercharger with a restricter plate reducing total boost or install a wastegate on your charge piping that vents boost to atmosphere at a certain psi. These are not commonly done although hks kit does come with a restricter.

[PandaSPUR]

Originally Posted by xsnapshot

I am doing something like this with my car and a Moto-East tune.

It's not a boost controller, but power IS reduced up top via reduced ignition advance. (maybe other things as well like valve overlap or something...Mike would have to chime in on that).

The high boost pulley does provide a little more down low and in the midrange, but I was wary of how much power it puts out up top. It's all about how much torque the motor is putting out. So if you can reduce the peak cylinder pressures and torque via reduced ignition advance or cam timing, 12 psi can be safe up top as well.

Looking forward to hearing how that works out for you. With that option, you could theoretically ask for different maps (each producing different top end numbers) and swap between them without going back to the tuner right?

Originally Posted by sw20kosh

Super chargers are mechanically driven and thus produce a set amount of boost at any given rpm. You cannot control it like a turbo...

Ways around that limitation is to choke the intake on the supercharger with a restricter plate reducing total boost or install a wastegate on your charge piping that vents boost to atmosphere at a certain psi. These are not commonly done although hks kit does come with a restricter.

lol right, so you'd control it the exact same way you'd control a turbo. Once boost hits a certain psi, wastegate opens and vents the excess. Thats what I'd want to do, looking to see if there are any ways to do it with this kit or if I should just stick to the normal pulley route. You cant control how fast the supercharger spins just like you cant control how fast a turbo spins, unless I'm missing something?

[CSG Mike]

Originally Posted by xsnapshot

I am doing something like this with my car and a Moto-East tune.

It's not a boost controller, but power IS reduced up top via reduced ignition advance. (maybe other things as well like valve overlap or something...Mike would have to chime in on that).

The high boost pulley does provide a little more down low and in the midrange, but I was wary of how much power it puts out up top. It's all about how much torque the motor is putting out. So if you can reduce the peak cylinder pressures and torque via reduced ignition advance or cam timing, 12 psi can be safe up top as well.

It's not quite that simple...

[xsnapshot]

Originally Posted by CSG Mike

It's not quite that simple...

I don't know exactly how it's being done on my car. I know it involves ignition advance and maybe cam timing. That's something Moto-Mike would have to answer.

But do go on and enlighten us....

[CSG Mike]

Originally Posted by xsnapshot

I don't know exactly how it's being done on my car. I know it involves ignition advance and maybe cam timing. That's something Moto-Mike would have to answer.

But do go on and enlighten us....

It comes at the cost of (an insane amount of) heat. It's okay if its a street driven car that rarely sees redline, but if you do any sort of spirited driving (which I suspect you do if you own a jrsc), I don't recommend that type of intentional power drop, unless its very minor.

[PandaSPUR]

Originally Posted by CSG Mike

It comes at the cost of (an insane amount of) heat. It's okay if its a street driven car that rarely sees redline, but if you do any sort of spirited driving (which I suspect you do if you own a jrsc), I don't recommend that type of intentional power drop, unless its very minor.

Any ideas about a safer way to intentionally drop power with the HBP installed? Or should guys like me just stick to the normal pulley.

[CSG Mike]

Originally Posted by PandaSPUR

Any ideas about a safer way to intentionally drop power with the HBP installed? Or should guys like me just stick to the normal pulley.

That depends. What exactly are you trying to accomplish, and what do you do with the car?

[PandaSPUR]

Originally Posted by CSG Mike

That depends. What exactly are you trying to accomplish, and what do you do with the car?

Mostly street driving. Still haven't taken it to a track or drag strip yet (planning to do so before I ever go FI). But I would like to track it once in a while.

I want more power with some space to grow. Originally was thinking of going with a FBM stage 1 with all the supporting mods. But realized that would take out all my cats and make me fail emissions testing in NYS.

Don't want anything that would kill my transmission or put me at risk without a built block. So basically 300WHP max from what I've read.

[CSG Mike]

Originally Posted by PandaSPUR

Mostly street driving. Still haven't taken it to a track or drag strip yet (planning to do so before I ever go FI). But I would like to track it once in a while.

I want more power with some space to grow. Originally was thinking of going with a FBM stage 1 with all the supporting mods. But realized that would take out all my cats and make me fail emissions testing in NYS.

Don't want anything that would kill my transmission or put me at risk without a built block. So basically 300WHP max from what I've read.

If you have race fuel or E85, that'll give you a *very* significant jump. Now, if you combine that with the high boost pulley, you'll be golden.

I don't see any reason for you to be restricting your output.

[PandaSPUR]

Originally Posted by CSG Mike

If you have race fuel or E85, that'll give you a *very* significant jump. Now, if you combine that with the high boost pulley, you'll be golden.

I don't see any reason for you to be restricting your output.

So you're saying I'd be safe with HBP setup on stock engine (+ supporting mods listed in OP) running on 91-93 octane? Then if I want to go track it, I could just bring some fuel additive to achieve 100 octane and get more power safely?

My main concern is keeping the car safe and reliable on the streets, even when I decide to do some near redline passes on the highway >_>

[Deep Six]

I have to admit I'm confused with this conversation about reducing power up top by manipulating the tune. Why not just lower the rev limiter?


Mine was installed and tuned (HRI) last week and I set the limiter to 7K on map 1 and 7200 on map 2. Sounded good in theory however the revs climb so damn fast its become a nuisance. Going back to 7400 soon. I will just have to exercise constraint on track days. Gonna be tough because I love the way it leaps forward during 7K upshifts. I had no idea it would be this quick.

[sw20kosh]

Originally Posted by PandaSPUR

lol right, so you'd control it the exact same way you'd control a turbo. Once boost hits a certain psi, wastegate opens and vents the excess.

It is not the same. A turbo wastegate vents exhaust gas slowing the rate of spin of the turbine/compressor. This in turn controls boost.

Venting the boost pressure in a supercharged setup doesn't control the spin of the compressor. The compressor spin is directly proportional to engine speed.

[CSG Mike]

Originally Posted by Deep Six

I have to admit I'm confused with this conversation about reducing power up top by manipulating the tune. Why not just lower the rev limiter?


Mine was installed and tuned (HRI) last week and I set the limiter to 7K on map 1 and 7200 on map 2. Sounded good in theory however the revs climb so damn fast its become a nuisance. Going back to 7400 soon. I will just have to exercise constraint on track days. Gonna be tough because I love the way it leaps forward during 7K upshifts. I had no idea it would be this quick.

People often underestimate the system...