lowrolr

Have any of you guys done away with wastegates comepletely and only used bov for boost control?

knuts82

Not gonna lie thats a stupid question..

denmah

iTrader: (2)

do you have a theory on how this is supposed to work....?

i would like to hear it all jokes aside.

anyway that would be like using a VCR to play a DVD

they are different tools.

you can use a wastegate on a supercharger cold side setup and limit boost.

but a blow off valve does not have a bottom port, and the whole dynamic of it was not designed to bleed during high pressure situations only release air under vacuum and hold shut under boost.

basically the opposite of what you want a wastegate to do, most of the time.

itsslow98

iTrader: (18)

Not quite sure if this is a serious post.

Anchor

I think he's thinking of an overboost valve. I had one on my inline 6 turbo falcon pickup. 490rwhp through a gt35r. 4L 6. 4" dump and out the side wouldn't net enough backpressure for the internal wastegate. So we fitted an overboost valve on the intake pipe before the throttlebody. Adjusted it on the dyno so it bled boost perfectly once it reached 16psi of pressure.

itsslow98

iTrader: (18)

Im not familiar with them so bear with me.......it opens when it reaches 16psi only, like a wastegate? So what happens when you close the throttle and say there is 15psi left in the charge pipe? Wouldnt that cause compressor surge and eventually damage the turbo?

Anchor

http://www.nizpro.com.au/overboost_valve.html

That, you're not really supposed to use it as boost control. But it works..

itsslow98

iTrader: (18)

So your basically using that as a wastegate?

dimetweaker

iTrader: (1)

Is there an RPM limit on a turbo?? if you ran a turbo up to desired boost pressure and then opened a relief valve on the compressor side, that thing is going to take off and spool like a ****!

Anchor

Was. Till i created some backpressure in the exhaust.

stevieturbo

Yes they do, and yes it works perfectly, because I'm doing it. ( supercharged obviously. For a turbo application it would of course be silly )

Use a 4 port solenoid, then your ecu or a suitable controller and job done.
I use it for boost by gear and also boost by rpm via my ecu. It would probably be more difficult with a generic controller though unless it was a very good one.

The Mondo and BV57 have ports that are readily accessible, the big red I'm using takes a little work to access the bottom side of the diaphragm. Nothing difficult though.

denmah

iTrader: (2)

but for an overboost situation the ecu should cut spark

and if you want boost by gear i think a wastegate is a better solution.

at least that is my opinion

stevieturbo

Overboost should never occur with a blower.

A Wastegate can work too, but why buy another valve with a smaller operating range when you can use what you have ? It's neater and cheaper and works better.

Obviously it will depend on the flexibility of your controller though. Some generic boost controllers might be difficult to get it all to work properly and in that case a w/g would be easier.

got-a-ls1

iTrader: (12)

i see absolutely no advantage to doing something like this on a turbo. you'll push the efficiency off the map and over spin the turbo.

if youre looking for overboost protection wire in a hobbs switch to cut power to the injectors when it is tripped. or you could just do what i did and zero out the ve table in the boost regions you want to cut. it cuts fuel and works perfectly. hit this about 20 times with my stock 5.3 with my cheap boost controller that spiked hard in the mid range. well back when i was afraid to go over 12psi.

stevieturbo

This is in no way suitable or desirable for a turbo setup

dimetweaker

iTrader: (1)

If you cut the fuel for a limiter and kept your foot in it, fuel would cut in and out like a rev limiter, and create a pretty solid lean condition, yes? cutting out spark would be a much safer idea.

stevieturbo

It's easy to think that could happen. But in reality, cut strategies on modern ecu's, that scenario just doesnt occur.

Even Racelogic's traction control cuts injector signals for a power reduction.


Many dont like cutting spark only, because it can leave a scenario where there are large volumes of unburnt fuel getting chucked into a very hot exhaust.

But most aftermarket ecu's you can select between a fuel cut, spark cut or both, as well as the aggressiveness of the cut.

lowrolr

[QUOTE=Anchor;17346538]I think he's thinking of an overboost valve.
Yes thats what i meant. Sorry for the confusion. Atleast everyone got a laugh. Lol thanks for your input

dimetweaker

iTrader: (1)

when you say modern ECUs, does that include all of the GM hardware we are using for LS motors? I had read ( speculation... ) that this was a problem, as in people saying they bounced on the limiter on a factory LS vehicle with boost, and the result was a blown motor. Is this more likely from a hard knock / detonation situation than a lean condition as speculated?

vwdave

iTrader: (3)

Everyone has to ask something dumb at sometime.