Supercharged LS bypass valve problem

[spf_lexus]

Im fairly new here at lextreme but i own a 91' LS and have been piecing "The Fish" together for the last 2 months. I have the bracket mounted, my IC mounted w/ all piping ran. I just got my maf adapter in the mail and I can finish off my intake, but I need to buy a relief valve, im having trouble deciding which one to buy. I am between either a TIAL bov or just gettting the boosted tundras "bypass valve" for this project. Any ideas whats more appropriate for this specific setup? finished it will run a vortech V1.

any help appreciated

sean

 

[striker]

which one is teh boosted tundra's one???

I need two eaton style bypass valves for my project, and sofar only have found 2 company's selling the same thing, if there are more options please share.

Grtz Thomas

 

[boostedtundra]

A supercharger bypass valve and a turbo blow-off valve are two completely different valves. You must use a bypass valve with a S/C
The bypass valve is always open during high vacuum /cruise speeds or any normal driving situations. This re-circulates excess air back to the intake side of the blower,and eliminates pressure. As soon as it see no vacuum (eg,acceleration)or the onset of boost it closes and directs all air/boost in to the motor. Remember,the blower is engine driven and must have a way to get rid of excess pressure when the throttle plate is closed,or almost closed.
I have documented TRIPLE the amount of normal boost between the blower exit and the throttle plate when the throttle plate is suddenly closed (de-celeration) My bypass valve if shown on the Lextreme website or you can contact me through www.boostedtundras.com. Rob

 

[cribbj]

Rob, how about a link to your bypass valve?

Also, here's a dual port butterfly type that Whipple sell. I have this valve and plan to use the 2nd port for boost control, but haven't tested it yet on the motor.

I did some bench testing of it in my supercharged Supra thread, so you can get the cracking & full open pressures there.

 

[boostedtundra]

The bypass valve is shown on the Lextreme website---I fabricated these valves to be inline and the largest diameter of any on the market. They use a 3/8" vacuum line for rapid and positive response. They connect with a 1.5" hose. Anyone who wants pics can email me at [email protected]

 

[striker]

Hey John,

what the difference in the single and twin port?

I run 2 superchargers in parralel so the act as one, think I'll be fine running one bypass valve, but need an actutuator to opperate.

also what's the diameter of a normal M90 or M112 bypass valve, I can make the butterfly valve housing myself but have nothing to opperate it.

Grtz Thomas

 

[JustenGT8]

A supercharger bypass valve and a turbo blow-off valve are two completely different valves. You must use a bypass valve with a S/C
The bypass valve is always open during high vacuum /cruise speeds or any normal driving situations. This re-circulates excess air back to the intake side of the blower,and eliminates pressure. As soon as it see no vacuum (eg,acceleration)or the onset of boost it closes and directs all air/boost in to the motor. Remember,the blower is engine driven and must have a way to get rid of excess pressure when the throttle plate is closed,or almost closed.
I have documented TRIPLE the amount of normal boost between the blower exit and the throttle plate when the throttle plate is suddenly closed (de-celeration) My bypass valve if shown on the Lextreme website or you can contact me through www.boostedtundras.com. Rob

You can use a BOV as a bypass valve Just need to make sure you understand what's doing what so you get all the plumbing right. Over 1000km on my M90 setup thus far with a $30 Ebay BOV and still working fine.

Price is about right for you Striker...maybe a little expensive ;-)

 

[cribbj]

The single port is a conventional bypass actuator; it has the port above the diaphragm, so that negative manifold pressure sucks (pulls) the diaphragm and actuator rod, and opens the butterfly.

The dual port has a 2nd port under the diaphragm, so positive (boost) pressure "pushes" the diaphragm and strokes the rod and opens the butterfly.

With the 2nd port, it can then be used with a manual or electronic boost controller to limit boost, similar to a wastegate in a turbo setup. That's my theory anyway; we'll see how well it works in June on the next dyno session.

Here's Rob's bypass valve:


Available on this page: http://www.lextreme.com/allgo.html

Rob, could your valve be fitted with a 2nd port to operate like the dual port actuator? If so, your valve would be more compact, and I think much easier to fit to a Roots/twin screw/Richwood setup than the butterfly type.

 

[striker]

@ Justin, What no way far to much $$$ offcourse, :biglaugh:

care to share what you did on your set-up? I have the provision in the new manifold to get a butterfly valve installed in the bottom of the manifold, in the valley. I will only have to drill the holes for it so thats easy. I plan to have the intake throttle(s) at behind the rear waterbridge, and I because of that I can the have a very neat (invisible) route for the bypass plumbing. also I will the have the bypass valve after the intercoolers, as per the original BMW installation.

I know how the bypass system works btw, I just wonder why the eaton manufacturers and users all use the butterfly thingy's which you can't find anywhere on ebay or such.

since the 2 eatons act as one, I take I don't need two seperat bypasses which would probably be a nightmare to get closing at the exact same moment.

anyway please share what you did.

Grtz Thomas

 

[boostedtundra]

Unless you have figured out a way to hold the BOV open all the time that you are not in boost--then the BOV is not doing what a S/C needs
As I understand the function of a BOV --it just opens momentarily to bleed turbo boost then shuts again. A supercharger system needs it open all the time until the valve senses lack of vacuum ans/or boost,then shuts

 

[JustenGT8]

^^^ exactly and what does a BOV do under vac? stay open of course It's an adjustable one so you can set the spring pressure pretty soft so doesn't take bugger all vac to hold open. Plus the way it is plum,bed you have the flow path also acting on the BOV valve (valve style BOV of course) which also holds it open and vice versa on boost the manifold pressure ensures it stays shut.

It works mate have no fear of that...i know boats

Striker, pretty straight forward. BOV hangs off the side of the plenum entering the SC and plumbs down into the manifold. Flow path from, the plenum is past the opening valve so it's actually helping to push it open...hope that makes sense.

You can kinda see the setup here....http://lextreme.com/forums/showthrea...6163#post86163

 

[JustenGT8]

Hm,m,m, try again...here

http://lextreme.com/forums/showthread.php?p=86163#post86163

 

[stevechumo]

Very interesting info about the bypass valve and the BOV. I think Spf_lexus is using the centrifugal supercharger and he needs the BOV. I believe he can place the BOV the same way as with the turbocharger. The centrifugal supercharger builds boost as the engine turn faster. It's similar as with the turbocharger, where it builds boost when the engine makes more power. The piping system is the same between the 2 systems. The BOV should be placed far before the MAF. I used to place it after the MAF and the engine stalled when I let off the gas...LOL.

 

[NZ_V8farmer]

My understanding of supercharging and turbo charging but from what i gather from here and other sources your both right a normal valve is the "proper" way of doing it, but justin is very right too in the a BOV set up right will work extremly well if not better in my opion.

 

[striker]

hmm nice!

food for thought.

I presume you could also use it as a boost limiter?

grtz Thomas

 

[JustenGT8]

hmm nice!

food for thought.

I presume you could also use it as a boost limiter?

grtz Thomas

Not anywhere near as controllable as a dual port actuated butterfly valve in that application but yeah i imagine a modluated solenide valve could control things well enough to give some level of boost control?

 

[cribbj]

hmm nice!

food for thought.

I presume you could also use it as a boost limiter?

grtz Thomas

Justen's, (and any standard BOV setup) is vacuum actuated, so I don't think they can be used for boost control.

There's not much vacuum available when you're going down the road at 20psi of boost....... That's why you need two ports on the valve. One above the diaphragm to open it under vacuum, and one under the diaphragm to open it under boost.

 

[striker]

@ cribbj, can you set the treshold of the boost diafragm in some way?

the plan is to make the valve and housing myself on the lathe,(because I like that) and buy a diafragm from someone and mount it all up.

what does such an bpv actuator cost anyway?

Grtz Thomas

 

[cribbj]

@ cribbj, can you set the treshold of the boost diafragm in some way?

Not that I'm aware of - this unit is completely sealed, so the spring is fixed, and there's only one spring available. I had planned to make it controllable by PWM'ing a solenoid valve, similar to the way we control wastegates.

the plan is to make the valve and housing myself on the lathe,(because I like that) and buy a diafragm from someone and mount it all up.

Wow..... that's the ultimate in DIY. Sounds to me like you're just looking for an excuse to buy a new machine tool!

Why not just take a motorcycle throttle body and cut off what you don't need, weld a little bellcrank to the shaft for the actuator, and voila.

what does such an bpv actuator cost anyway?
Grtz Thomas

$69 IIRC, hehehe

 

[striker]

Wow..... that's the ultimate in DIY. Sounds to me like you're just looking for an excuse to buy a new machine tool!

:bigok: BUSTED!!!:irked:

nah no MC valve that's called wasting, far to much fun bolting them to 4age's

I have a complete T-vis manifold in a box somewhere, I'll dig it up and take one of the butterfly valves, and make an ITB out of billet 6061t6. the thought of it working when lifting the throttle when you're on the road is far to much fun, I made that myself!

+ indeed being a true scotsman or whatever I have a stash of T6 round bar lying on the shelf waiting to be carved in something beautifull, which I got for free offcourse! (well.... ok I wired up his car)

for the actuator, would a t-vis actuator diafragm also work? it pulls a lever when you put vacuum on it, I however do not know at how much vacuum a normal (eaton lysholm etc) one opperates, any ideas?

it might all stike as el cheapo but I bet a new T6 billet one would look far better than an old MC ITB, and be just as cheap.....

Grtz Thomas