supercharger vacuum

[mudsurfv6]

1996 vzn185 3.4 v6 5vzfe surf & TRD supercharger.

on dial up until broadband gets sorted so not so easy to google.

surf is running ok most of the time but having problems sorting out one thing, on the back of the supercharger there is a butterfly type of arrangement but not sure how it works or what its for. is it a sort of bov or release for too much boost?

and there is a small hole that is a vacuum when at idle but turns to positive pressure when revving. in centre of photo above round rusty looking hole. what is it? and where is it supposed to go? is it supposed to have a pipe attachment sticking out of it? when you block the hole, at idle it runs really rough and just about stalls.

[dvk-kp]

I'd say the butterfly thing is to recirculate air when it's idling. Same setup as what the supercharged v6 commys have. Stops it loading up on a closed throttle I think. Could be wrong tho.

No idea what the other doofer is tho.

[mudsurfv6]

hey bro

there is a pipe fitting coming off the butterfly thingy. on the commodore do you know where that pipe goes to?

[dvk-kp]

I always thought it just went to a vacuum port after the throttle body but before the supercharger so it opened the butterfly at idle when there's vacuum there. That's what I was going to try on mine but using a modified BOV instead. I could be totally wrong and I'm sure someone will point us in the right direction if that's the case

Good to see its still making progress, must be itching to get it in the mud!

[mudsurfv6]

Good to see its still making progress, must be itching to get it in the mud!

slowly. with moving house not much has been happening. won't be in mud for a while though, body chop, deck & cage, steering brakes, front bump stops plus smaller stuff to do. one day

I always thought it just went to a vacuum port after the throttle body but before the supercharger

there are two factory blanked off ports there.

i'll get up there to drop your transfer case and hubs etc off one day.

[Big]

its bypass valve and MUST see vac and boost so best to place on manifold somewhere the hose as it closes under boost and opens under vac..otherwise the setup will either bypass boost pressure and not see much boost ass it is not closing , i have mine hooked to the map sensor feed as it sees both vac and boost..

[dvk-kp]

i'll get up there to drop your transfer case and hubs etc off one day.

Haha all good. I forgot about that. Just when ever.

its bypass valve and MUST see vac and boost so best to place on manifold somewhere the hose as it closes under boost and opens under vac..otherwise the setup will either bypass boost pressure and not see much boost ass it is not closing , i have mine hooked to the map sensor feed as it sees both vac and boost..

I thought the bypass actuator was spring loaded and full vacuum was only enough to open it, so as soon as the throttle was touched it would close. Does the map sensor feed come from under the SC? Makes sense really.

[mudsurfv6]

its bypass valve

are you talking about the small hole in second photo? or butterfly arrangement in first photo?

[mudsurfv6]

I thought the bypass actuator was spring loaded

if that's the black thing then yes it is spring loaded. there is a steel rod going from black thing to butterfly that has a strong spring working it.

[mudsurfv6]

and MUST see vac and boost so best to place on manifold somewhere the hose as it closes under boost and opens under vac

that small hole in other photo is vacuum at idle and positive /boost? with revs. would that work joining the two?

[Big]

well this is my setup..connection that doesnt have a pipe on it goes to map sensor feed so that see's vac and boost, the pipe attached to the bypass valve also see's vac and boost.


On the T that goes to this


which operates the fuel pressure reg, so again this see's vac and boost.. when in boost it ramps up the fuel pressure more which is a bonus

This is how I have set mine up..

[dvk-kp]

Nice setup big, what's that bypass off? Probly run exactly the same on mine. Does it control boost or is that just dictated by pulley sizes? I read somewhere if ya use a BOV instead of a bypass, ya can set it up to control boost?

Sorry to hijack ya thread a bit Andrew. Just doing some learning

[Big]

Nice setup big, what's that bypass off? Probly run exactly the same on mine. Does it control boost or is that just dictated by pulley sizes? I read somewhere if ya use a BOV instead of a bypass, ya can set it up to control boost?

Sorry to hijack ya thread a bit Andrew. Just doing some learning

Bypass is off a mini cooper and it operates solely by throttle.. more you push it the harder it works..ie not much boost bypass allows some pressure release.. WOT throttle fully closed, no throttle fully open this allows for air to bypass the SC so its not working against itself
Yes you can use a bov but I would use a bypass as this works better instead of bypassing to atmosphere..

Sorry for thread jack also.. Just trying to allow info to help everyone

[mudsurfv6]

Sorry to hijack ya thread a bit Andrew. Just doing some learning

Sorry for thread jack also.. Just trying to allow info to help everyone

sweet as, don't know what your talking about though.

well this is my setup

cheers for that. will try and make sense of it.

[dvk-kp]

The butterfly is there to allow pressurised air from under the supercharger to recirculate back into the intake before the supercharger when at idle, so it just free spins I guess and doesn't load up.

The butterfly is controlled by that black actuator... What Big is saying is You need to attach the vacuum port on the actuator to the manifold after the supercharger so it sees boost and vacuum. When the engine is idling and there is vacuum present it will cause the actuator to open the butterfly and the air will circulate back to before the supercharger as the engine doesn't need it... When you touch the throttle, the butterfly closes and the pressurised air can't bypass and goes thru the engine, thus boost and the more boost, the more pressure holding the butterfly close...

Hope i got that right and it makes sense!

[Big]

The butterfly is there to allow pressurised air from under the supercharger to recirculate back into the intake before the supercharger when at idle, so it just free spins I guess and doesn't load up.

The butterfly is controlled by that black actuator... What Big is saying is You need to attach the vacuum port on the actuator to the manifold after the supercharger so it sees boost and vacuum. When the engine is idling and there is vacuum present it will cause the actuator to open the butterfly and the air will circulate back to before the supercharger as the engine doesn't need it... When you touch the throttle, the butterfly closes and the pressurised air can't bypass and goes thru the engine, thus boost and the more boost, the more pressure holding the butterfly close...

Hope i got that right and it makes sense!

Bingo

[mudsurfv6]

Hope that makes sense!

think so.

so what about that small hole in second photo? got us stumped. sucks like hell at idle but blows when revved. if you put finger over when idleing it makes engine run really rough.
obviously should have a pipe fitting sticking out, but where would/should pipe go to? whats it for?

piggy back computer not wired in yet if that makes a difference. some of the yanks run without though.

[dvk-kp]

No idea, maybe something to do with idle control?? Just guessing tho. Seems strange that blocking it makes it run rough.

[Madaz]

Hope that makes sense!

think so.

so what about that small hole in second photo? got us stumped. sucks like hell at idle but blows when revved. if you put finger over when idleing it makes engine run really rough.
obviously should have a pipe fitting sticking out, but where would/should pipe go to? whats it for?

piggy back computer not wired in yet if that makes a difference. some of the yanks run without though.

Have you hooked up the bipass valve in picture 1 yet?
If you havnt done that yet, that hole your blocking off in picture 2 mite be where the engine is sucking in air to get it to idle?
Possibly why engine starts running rough when you block it off.

[mudsurfv6]

just looked on gadgetonline.com and its the second boost port, 'normally connected to the bypass valve actuator'.

just got to figure out how to hook it up.

[mudsurfv6]

that hole your blocking off in picture 2 mite be where the engine is sucking in air to get it to idle?

so your thinking it should be hooked into intake before sc, so filtered but not forced? somehow with bypass actuator?

[Madaz]

that hole your blocking off in picture 2 mite be where the engine is sucking in air to get it to idle?

so your thinking it should be hooked into intake before sc, so filtered but not forced? somehow with bypass actuator?

I think you might be able to block it off once the actuator is working, and that all its doing at the moment is acting as a leak, but its letting enough air in to keep ur engine running. Hence why it starts coughing when you block it off.

[Big]

Looking at the first picture im thinking that the hose that goes to the fuel pressure reg could be also connected to the bypass valve you have.. part with the hose currently not connected to.. that way it see's vac and boost.. Cant quite see what is wrong in picture 2..

[mudsurfv6]

seems to be running ok at the moment. can't accelerate quickly because piggy back computer not wired in and it just puts into limp mode.
so next job is wire computer in and hopefully all go.....