Hey everyone,

My car:
1988 Chevrolet Beretta GT.
3.1L MPFI v6.
5 SPD trans.
Centerforce Stage 1 clutch.
Stage 2 Racing chip.


I bought an Eaton M62 Supercharger. I found this link that explains how the boost bypass valve is controlled:
http://farm7.staticflickr.com/6098/6378719399_8934cb429b_z.jpg

1 = Boost Bypass Valve Actuator
3 = Boost Control Solenoid
4&5 = Supercharger
7 = Boost Bypass Valve
8&11 = Throttle Body

Basically the thing operates in 2 conditions:
1) When boost is not needed, like at idle, or cruising.
2) When boost becomes to high.

I know the best way to control boost with a supercharger is to buy a smaller pulley. But this supercharger, is has a solenoid that the origional 3800 v6 engine it was from, controlled with the ECM.

Because this is a turbo forum, and I know a lot of people who buy turbochargers and work with them are familiar with Blow off valves and BOV controllers, I was wondering if I could get some help/advice.

In the photo there is a solenoid. Previsouly, that solenoid was controlled by ECM, the solenoid controlled the bypass valve, from there that controlled the boost pressure.
(Bypass valve in a Supercharger is like a blow off valve in a turbocharger, only difference is mine is all internal).


My question:
Does anyone here know of an electronic controller I can buy, where I can have it in my car on my dash somewhere, and turn a knob. Which will increase or decrease my boost pressure?
Something simple that just works, and doesn't cost to much? (hopefully no more than $150)

The knob would be connected to a controller, that controller would electronically read the boost pressure in PSI, and then control an electronic solenoid like in the photo to open the bypass valve and decrease boost pressure when needed?

I found some non-electronic ones that are just a valve that goes under the hood. And thats fine and all, but the darn thing costs 90 dollars.
I see some crazy electronic controllers that do everything for 250 dollars, and I'm hopinng someone here can help me find one for about 150 dollars or less that simply adjusts boost pressure. Maybe even shows a digital readout of the current PSI?

I have everything purchased and sorted out, except this. I have no idea how to make the bypass valve (blow off valve equivalent) work without a way to control the solenoid.

Schematic in link above.

 

I never thought of it that way.

Yah, the bypass will open when it sees a vacuum because it doesn't need the supercharger on at full blast.

My main concern was when I put it at WOT, Because then the bypass will close because it sees it needs the supercharger at full blast.
I'm just worried I'll end up with to much boost for my engine, and I was hoping for something that I could control and reduce boost while driving if needed.

Do you think I could use a manual boost controller? Its just a valve with an in and an out hose, you turn the valve and forget it.


The 3800 v6 engine I got the M62 from was 8.5:1 compression with a 7" crank pulley.
Mine is a 3.1L v6 with 8.9:1 compression and 6" crank pulley.

 

Just use a manual boost controller and a boost gauge, hook up your air compressor to test your setup so the gate opens at whatever you set the knob too.

 

I'm lost. Pulley it to make whatever you want max boost to be and leave it alone. You're making this about 1000x more complicated than it is.

 

I was just reading that that will not work since on engine the exhaust pressure is also trying to push the WG open.

 

First off to clarify a few things on the Eaton Supercharger.

1) The By-pass was implemented to take some of the "belt" drag load from the supercharger off of the engine to reduce the idle emissions and loss in fuel economy on the EPA Emissions and F.E. testing. It is not a wastegate for exhaust side of the engine.

2) The by-pass quickly closes with any low vacuum conditions or ANY Boost level. So the boost is controlled by the Belt drive ratio vs the engine rpm. (PULLEYS).

3) Max Boost on an Eaton Supercharger based on a maximum supercharger rpm of 14000 rpm. Most times the pulleys are sized in the 10,000-11,000 supercharger rpm range.

So playing around with a vacuum control actuator that does not really bleed off any boost pressure (on a stock calibration) unless the factory assumes that the engine will see very high
rpm from an abusive driver and even higher supercharger speeds (boost) and so they have a "protect mode" in the EEC to at least try to save the engine.

Tom Vaught

 

Pretty sure the 3800 series II engines came with the M90, and not M62? How are you getting the supercharger from the 3800 (90 degree V6) to fit on to the 3100 (60 degree V6)?

 

Agree the 3800 engines had the M90 Eaton unit on them (both at Ford and GM).

TV