Prodigy Performance 3.6 Turbo DIY Install

[FieryRobot]

But you can add a wastegate to a supercharger, no? Especially a centrifugal one.

[UselessPickles]

But you can add a wastegate to a supercharger, no? Especially a centrifugal one.

Technically, yes, you could setup a supercharger system with a wastegate (or some sort of precision bypass valve) on the intake somewhere after the supercharger. Then you could use a smaller pulley wheel to over-spin the supercharger some, while relying on the wastegate/bypass to limit boost. With a centrifugal supercharger, this would give you peak boost before redline, then hold peak boost up to redline. With other types of superchargers, it would just over-work the supercharger constantly unless you drove up to a higher elevation.

The big difference between this idea and how a wastegate fits into a turbo system is that on a turbo, the wastegate limits the speed of the turbo. The wastegate bleeds off exhaust, around the turbine side of the turbo, limiting the turbo speed, and indirectly limiting boost. With the supercharger setup, the wastegate would be directly bleeding off boost pressure, but the supercharger would still be spinning faster than necessary to generate the controlled amount of boost. Faster supercharger = less efficient = more heat.

This variable ratio ProCharger looks pretty cool, though: http://www.lsxtv.com/news/procharger...-supercharger/

[gbaumann]

Technically, yes, you could setup a supercharger system with a wastegate (or some sort of precision bypass valve) on the intake somewhere after the supercharger. Then you could use a smaller pulley wheel to over-spin the supercharger some, while relying on the wastegate/bypass to limit boost. With a centrifugal supercharger, this would give you peak boost before redline, then hold peak boost up to redline. With other types of superchargers, it would just over-work the supercharger constantly unless you drove up to a higher elevation.

The big difference between this idea and how a wastegate fits into a turbo system is that on a turbo, the wastegate limits the speed of the turbo. The wastegate bleeds off exhaust, around the turbine side of the turbo, limiting the turbo speed, and indirectly limiting boost. With the supercharger setup, the wastegate would be directly bleeding off boost pressure, but the supercharger would still be spinning faster than necessary to generate the controlled amount of boost. Faster supercharger = less efficient = more heat.

This variable ratio ProCharger looks pretty cool, though: http://www.lsxtv.com/news/procharger...-supercharger/

I think Pickles is spot on. And, I don't mean to hijack this portion of the thread but since we're talking about bypasses and wastegates and how to make desired power I thought I'd "share."

The engineers for these power mods are much smarter than me so I'm sure there is a good reason for bypassing superchargers. I'd just like to know what it is. I understand wastegate operation on a turbo. The turbo boost is not linear with exhaust flow. There's no ideal blade pitch for low RMP through high RPM. Pick a good one for lower RPM operation which would produce too much boost at high RPM and adjust by bypassing exhaust. It's elegant. Makes sense to me, that is, unless the wastegate is eliminating boost altogether which I presume it isn't.

But the bypass on my supercharger is binary (in the case of Magnuson). You're either putting boost into the engine or your're not. There's no middle ground according to Mag. The bypass closes when manifold pressure is ZERO which is pretty near WOT. Great for a dragster. But not for a daily driver. Seriously, the compressor is turning all the time. Why not use the boost better and throughout the RPM range? Again, smarter people than me I'm sure have concluded that you need boost to get you from 0-60 (assuming that you've got your foot all the way to the floor) but you don't need boost when you get there. We'll they haven't' driven my jeep. They've driven corvettes or challengers which have one big difference. When they get to 60 mph and the supercharger goes to bypass the car is still being powered by a big motor. They started life as powerful HP to weight ratio vehicles. Superchargers take them from really fast to downright irresponsible.

But that's not us. We have jeeps. Big, square, heavy, full framed, solid axle, locking differential, large diameter tire jeeps. We started life under powered and overweight. I want boost at part throttle so when I speed up from 40 to 60 mph or 70-80 mph the truck accelerates with confidence. And I don't want to get that by opening up to WOT. There's no need for it. It just causes my auto trans to downshift. Heck, if I want to increase acceleration by lowering gears then I'd put 5.11's in the diffs and accelerate in third gear at around 5 thousand rpm's. I'm sure she'd pin me in the seat and I don't need a supercharger or turbo to do that.

So I've made a decision. For those of you who know that I'm struggling with the "lift to sift" issue I've found new PCM that I can install that will finally control my auto trans. I'm going to have it installed for me after the new year. Good new is it should meet my need for better shifting and all-time power. The catch is the PCM costs $25,500 to install and comes with a 6.4L hemi.