here the m90's sc are about $300 tops second hand.. and to do the turbo swap is average about $4000.. that huge difference.

bypass valve
 

what is that bypass valve from? what car please tell me.... im almost there

That "bypass valve" looks suspiciously like my $20 bosch BOV I have.. from either a saab, mitsubishi, volvo... etc..etc..

where can i get that bypass valve from? for 20 bux?

Ebay is always a good bet for anything

who here is actually going to do this? im going to the junkyard tomorrow to pull myself a eaton m90 supercharger , my friend owns a yard and sait 100 bux if I pull it....cant beat that with a stick! ill be hunting this week, just not for eggs!

You quoted my post but didn't appear to read it. I never they wouldn't work, I said they would be restrictive. RB headers are designed for naturally-aspirated engines, not supercharged ones. More powerful engines needs bigger pipes or their power will be restricted by the exhaust. It's a pretty simple concept.

I assume you mean the auxiliary ports. Wiring open the secondary throttles would be a very bad thing...

So if I weld my own custom exhaust as true duals as 2 inch each I should be ok? Including the header. But when I think about it, the racing beat racing header is 2 inches, so i should make one 2.5inches?

Maybe I could make it 2 inches as a true dual because people here were referring to a collected system???

anyways, it's fun to think about, and great job on the supercharging man!...later:)

Re: sc question
 

Smaller SC pulley = more SC boost


-Ted

other things
 

Man i really appreciate your input on this thread. If you don't mind and have the time, I would really like to hear what else should be considered. I realize that this can end up a disaster if you take the wrong things for granted!

Dave

wow... very nice

So can someone answer my questions? The air bypass is recylcing the air back into the intake before the charger right? And the tube coming off the back of it goes where? Is it a calibration tube so that it knows when to let air through?

Yes, thats exactly what I did.

Come on guys, stop arguing about reading each others posts and give some real answers. I know you guys are knowledgable enough.

I finally got ahold of and eaton 90

sweet let us know how it goes. dezerte..

Basically the bypass is just like a BOV, and since it's recycling air that's already been metered (at idle, not decel), it has to be routed back to the intake (before the supercharger, otherwise you'll have pressure on both sides. It differs from a BOV in the sense that it is open even at idle, since your plates are too closed, but the supercharger is still spinning fast enough to create boost. This is done by either a vacuum line to open it (it should NEVER see boost, only vacuum), or too much boost pressing on the valve. Now a blow off valve will help alleviate the high RPM shifts where the bypass valve is overworked. I hope this helps.

Thank you very much sonic, That's what I thought, I just wasn't sure. Where would the vac line be run to get vacuum at the right time?

stock TII has a bypass valve.. would probably work fine for this.

pat

If this is not an April Fools joke then I hand it to ya. Good job for a 19 year old. Nice welds too... Give us more details and pic and let us know how it all works out. I AM IMPRESSED!!!

This is going to be an awesome project... when he said he was going to install a blowoff valve, does he mean hes going to have a blowoff valve AND A bypass valve?

Yeah, the bypass valve can't relieve all the pressure at high rpms so he is putting in a BOV to relieve the extra pressure.

Anything after the throttle plates should see vacuum at idle, since it can't suck in the air (due to the fact that they're closed) This should allow the valve to open, however there's always some air that escapes, wether or not this overcomes the total ammount of vacuum, I can not tell you. But that's how it should be setup. For those of you who asked prior if he was going to use a BOV and a bypass, he said this is what he was planning on doing, as the bypass couldn't relieve enough pressure at high rpm/load.

Please be aware that the BOV and bypass valve are not set up the correct way.

They do work but they are used to save money by not having to relocate the throttle body.

The correct way would be to have the SC suck through the throttle. A bypass valve in this setup would be nice but not strictly necessary. A BOV would not be necessary at all because a roots style SC has constant boost.

However the correct way is more complicated and more expensive. This incorrect setup does work but he is running into some problems with not being able to bypass enough air so he needs two of them.

ed

I might be wrong but I haven't looked down the throat of my throttle bodies lately.

You can wire the vacuum operated throttles open but you must leave the throttle linkage operated throttle plates alone.

A lot of ITS racers remove those throttle shafts completely.

Maybe I have the naming convention confused?

ed