3800 Boost Bypass Idea

[98 TGP TOY]

Hey guys, as I was looking at the extra m90 i have, i got an idea. Now I'm not saying this is original, but I have never heard of anyone trying this. Also, I know Ron has done sometype of mod with the boost bypass, but I forget what that is.

So anyways, There is a bolt underneath the control arm of the boost bypass. And when the supercharger is off the car you can gain access to the underside of the bolt. The underside of it is designed for a allen wrench. So I was thinking, you could unscrew this bolt and then screw it back in the opposite way (allen wrench part facing up). Then put the m90 back on the car, and now you can adjust that bolt at anytime. Meaning you can control whether the boost bypass would close all the way. Therefore you could keep it open a little bit and lower boost levels, because some air would go through the bypass.

Now for the questions. Would this effect drivability or set a code? What problems might occur by leaving the bypass open a little bit? Is this a stupid idea?

I was thinking some advantages might be:

If you have kr and cant solve it right away. Instead of getting a bigger size pulley, you could just keep the bypass from closing all the way.

If you want to put on a smaller pulley for the track and run race gas. Then on your way to and from the track you could keep the bypass from closing all the way and so if you wanted to floor it around, you wouldnt have to have race gas in yet or worry about massive amounts of kr.

So what do you guys think? Again, im not claiming this to be all my idea, just something Ive never heard before. Thanx.

Click to read more...

 

[imported_Ron Vogel]

Well the bolt you're talking about is a stop for the butterfly valve. It's easier to bend the tab that contacts it with needlenose pliers. The best way I can think to use the bypass system I could think of is the soleniod off of the vaccum actuator. It has a 12 volt lead into it, I found that supplying it a lower voltage will limit boost. When I would normally run at 11 lbs of boost at 12.8volts supplied to the solenoid, 9 volts woult limit me to 8 lbs. The soleniod basically limits bleed off of the vaccum in the diaphragm of the actuator. To test this, dicconnect the connector to the solenoid and go for a drive, your boost should not exceed 5lbs.

 

[98 TGP TOY]

Well I was thinking with the bolt, you could move it to various positions. Therefore you could lower boost a little, or lower it alot, and not have to bend that tab.

So what does cutting the voltage do in terms of the butterfly valve. Does it cause it to stay open a little bit?

Thanx.

 

[imported_Ron Vogel]

The boost bypass butterfly only opens when the vaccum actuator moves it. The soleniod doesn't let the vaccum bleed off from it all the way and it won't close beacuse of it. With the bypass not allowing it to close, you don't build the same boost. What's nice, is that you can cotrol the amount and when it goes full that way.

 

[98 TGP TOY]

So would leaving the butterfly valve open a little cause a drop in boost? Im assuming so, and would it cause drivability or wot problems?

 

[98 TGP TOY]

OK, another crazy thought, and I may have this backwards. But, from what Im understanding, if you limit the vacuum thats bleeding off, then your keeping the butterfly valve open, and therefore less boost. Do I have that right?

If so, then could you put a manual turbo boost controller on the vac line that is bleeding off. Therefore, you could limit whether it all bled off and shut the valve completely, or you can restrict the vac, and therefore have it stay open more, causing less boost.

This is more of just me coming up with crazy ideas, then actually implementing anything. Just trying to understand the car better. Thanx.

 

[beyerch]

actually i was out playing with this wiht our new software and you can control this on the fly with it. Its a neat way to have a launch control as you can open the valve off the line and then specific when to close it. with my 3.25 if i was barreling down the street @ WOT, I'd see 5lbs with it full open and then it would jump to 10 when i closed it.

It will still build boost because the bypass opening is only so big and you are still back it up.

Its kinda neat though to be doing 50 and then close it and get that instant 5 psi of boost.

This might be a good solution for those guys who want to leave a small pulley on their car, they could just command it opened for normal driving. I'm working on incremental control so that you can actually set % open.

 

[imported_Ron Vogel]

Charles, that's the way to go with it. I found it'll stay about 5lbs and won't go any lower than that with the solenoid closed. I had a switch to flip it on and off instead of the electronic controller thingy for awhile. It is pretty cool to flip it at WOT, it's like hitting a n20 button. The only problem to watch out for are the LT's since the backed up boost goes into the intake, blows by the MAF and causes some turbulence. I noticed that with the race gas it would leave white residue in my f-duct where the boost backed up.

 

[98 TGP TOY]

Well that would be a cool mod to have. New software abilities....charles is a tease.

So was I at least correct in my thinking guys, or do I have it reversed? It would be nice to be able to control the boost easily.

Also, charles I pmed you back a couple days ago, but havent got a response. I know your busy, but I just wanted to make sure you got it. Thanx.

 

[beyerch]

i'll check the pm's i apologize but i was out of town and am now sick... pm's might even be full for all i know!

 

[98 TGP TOY]

Not a problem, I just wanted to make sure that it got to you. Take your time.


But back to the topic, So did I get this right ron or am I turned around? Because you can make a boost controller for like 10 bucks from lowes parts, and since I am having KR problems, I would be able to lower the boost until I got it resolved. Let me know, thanx.