Inliners International Forums General Discussion Blown and Injected wastegate or blowoff valve

This will be my first turbo build. I am planning on adding a turbo to an industrial 292. I have many questions before I start this build, but I will start with this one. I am planning to use an old TO4 turbo which has no wastegate. Can I get by with using only a blowoff valve, or do I need a wastegate, or do I need to use both?


Thank you

You should use both. The waste gate is in the exhaust potion of the system to regulate boost and the blow off valve is in plumbing after the turbo to protect the turbo when you slam the throttle shut. Gives an escape route for the excess pressure. Some people get away with out the blow off valve. Roll the dice, sometimes you win, sometimes not so much. I'm not an expert by far. I'm on my first turbo project also.

exhaust wastegate for sure. I do not run a blow-off valve on my charge pipe. I am also running a low PSI though. Good Luck and ask away! odds are one of us has been there.

I recommend using both.
No BOV, slam the throttle down after a WOT run and smear the charge side vanes of the turbo and then such them thru the engine.
No wastegate and not have control of the boost.

You can get away without the BOV in a low budget build. Many automatic guys don't use one ever. On a low boost (<10psi) build they would be a nice-to-have not a must-have. However, the wastegate is mandatory unless you are filming the first time you run it hard and then post the video on youtube!

56er I am planning 10psi or less and i am going to use a 700r4 you said automatic guys don't use a bov why is that?

I have said before, Syclones & Typhoons do not come w/a B.O.V.,stock they run 14.7 PSI,the turbo lasts 100,000-200,000 Mile range.

I ran up to 22 PSi w/no B.O.V & never had a problem w/the turbo or blowing off intercooler plumbing.

I now installed a B.O.V. only because I installed a 60-1 compressor wheel on a small shaft turbine wheel & I run up to 25 PSI.Just to take out some of the load on the turbine shaft/bearings & easier on the compressor wheel. Still,stock style Mitsubishi turbocharger.

Running a completely stock 700R4 trans.

MBHD

The thought process is that when the automatic shifts it maintains the load on the turbo, so it doesn't surge or overspeed like it could on a stick shift. Having said that, my turbocoupe didn't have a blowoff valve either, it was set at 14psi and had a stick shift. My 56 that I am building currently has a BOV, but that's just so I can hook up with Asian girls in schoolgirl skirts

On this video, you can hear when the guy closes the TB. the excess boost pressure is going out backwords throuh the turbocharger, this is how they all sound w/no B.O.V.

http://www.youtube.com/watch?v=Q-f3xDWNVag

MBHD

I was planning on running 8psi boost so I can probably get away

with running a wastegate. Are most external wastegates

adjustable or do you have to buy them preset?

Some are adjustable,some you change the spring inside & adjustable hardware to set your base boost pressure.



MBHD

Does anyone have any suggestions on a wastegate? I am planning to fab an adapter pipe from my stock exh. manifold to mount the turbo to so I will have to fabricate the wastegate mounting some how.


Thanks

Depends on how much power you are planning on making.

250 HP, 700 HP?


MBHD

I would expect a 35mm ish 'gate to handle most of what would be practical with a J pipe off the stock manifold.

Much past what that would control any you will likely be better off with a "weld ell" fabricated manifold, as a minimum.