Here is an interesting article about installing a turbo wastegate (in conjunction with the bypass valve) on a centrifugal supercharger to regulate boost. The idea is to use a high boost pulley to to reach your target boost quickly and set the wastegate to maintain that boost to redline.

If your target boost is 10 psi; use a 20 psi pulley and set the wastegate to 10 psi. Reach 10 psi by 3000 rpm and maintain 10 psi to redline. There may be some power loss up top due to extra heat but the increase in midrange TQ would be AWESOME.....


"Vortech Centrifugal Supercharger Wastegate Install - A Gateway to Street Supremacy"

http://www.musclemustangfastfords.co...egate_install/

 

sounds like a great idea , whos going to be the first to try it ?

 

Guys have been doing it for some time on the car/truck side. Run a big boost pulley and dump the rest when you hit the number you need. Pretty good idea that is tried and true.

 

I'm seriously considering this.

 

I'm thinking abou adding or to my Aerocharger setup as well... I have a couple sitting in the shed.

 

Alright I'm going to explain the down side of this. No need to reinvent the wheel here guy's.

A waist gate is used on turbos because it's not easy to regulate the boost pressure, there's no pulleys it's done by the exhaust flow, there is already large amounts of heat being generated from the exhaust so over boosting is controlled by the waist gate and the heat is helped out by the a inter-cooler.

Now on a supercharged engine it's easy to control the boost psi with pulleys. need more boost, swap pulleys, to much boost, swap pulleys. Now if you create 20 lbs of boost and only want 10 and use a waist gate to regulate it, your over working the supercharger creating more heat in it, shortening it's life span and costing eating more power from the motor to spin the supercharger faster than it really needs remember the motor spins the supercharger it's not free hp like the turbo from the exhaust.

Superchargers don't have the lag that a turbo does ether, there is some but not like a turbo.

If it would be worth while Frank would have already done it. The supercharged funny cars would have already done it. it's not worth the time or money.

 

I'm not really concerned about Supercharger longevity. Everything can be rebuilt.

This would provide to ability to adjust boost on the fly with the boost controller. If you wanted to build a Street/Strip bike this would be a great advantage. You could run a 20 psi pulley and set the waste gate to dump boost at 12 PSI. cruise around all week with no problems. Come race night, simply adjust the boost controller to say 18 psi, add some race fuel, load a tune and crush someones dreams. This would take less then 10 minutes.

This has been done on cars successfully. The article explains how it works and shows dyno graphs that prove how effective this is. If I can come up with an aesthetically pleasing design for this (and some extra cash) I will probably give it a try. If it goes on a Harley it has to look good and be functional you know..

 

boost wondering if anything ever came of this

 

Not Yet, I have been working on my other bike.

I have talked to a local turbo shop and have come up with an idea of how I want to do this. I plan to convert to the procharger side mount intercooler and mount the wastegate before the intecooler inlet. The vacume line will be mounted after the intercooler to more accurately control boost. I want to pully the procharger up to 18-20 PSI and set the wastegate to dump excess boost at 14 PSI. The goal is to hit 150 ft lbs by 3000 rpm and maintain to redline.

It may be a while still before I start this project.

 

Just make sure that you take into account the impeller speed with the new pulley at engine red line. Even though you're dumping boost the that thing is still going spin a lot faster.