Right, right, a wastegate does allow energy to bypass the turbo, however this is only at a preset boost level. That boost level is determined most of the time by an electronic boost controller by way of an on/off solenoid. Affixing wastegates to the manifolds neither inreases nor decreases spool time. The only time a wastegate will have anything to do with spooltime is when they get stuck open. A wastegate that in normal position is closed will allow the turbo spool just as if there is no wastegate at all. It's a matter of safety because the boost is going to shoot to 40psi the first time the throttle goes to 100%, and pistons are going to be sitting in the oil pan. How are you planning on controlling the boost?

Eric

 

ONCE AGAIN THANKS FOR YOUR COMMENT!

When my pistons are sitting in my oil pan, I'll make sure I call "You" LOL!!

 

Is that device on the lower intercooler pipe to control boost? I mean I'm no expert but sure looks like it to me.

 

Scott, what you're seeing is the blow off valve, or bypass valve as it's sometimes refered to. It releases excess charge air when the throttle plate is closed, but in no way controls boost That's the job of the wastegate

 

You are 100% correct Scott

 

Very nice work!

 

Thank You!

Whats the Mustang run?

 

im curious to know as well how the boost will be managed.

Unless its top secret, id like to know. I've always thought that the wastegate spring determined how much boost the turbo puts out.

 

The boost is managed by the wastegate, that you're correct. The wastegate has 2 holes. 1 in and 1 out. The tension of the wastegate spring is set at a preset force that pushes down the wastegate valve (it's more like a shut door for the inlet hole) to close any exhaust gas to be going inside the wastegate and go out the other hole, or you can call it "vented out".

When the exhaust gas reaches enough pressure that can push the wastegate valve against the wastegate spring, the valve will be opened and the exhaust gas will be vented to the second hole (out). This hole will usually direct the exhaust to the downpipe, then muffer, then outside. Some system re-vent this exhaust gas to before the turbo.

The boost is in termed measured as psi of pressure above the atmospheric pressure. When you have the boost gauge reads 10 psi, that means the 10 psi of pressure after the turbo that goes to the engine, not before the turbo. I haven't found any tech note on the exhaust pressure that can push against the wastegate to make it open.

This exhaust pressure is very great. So when you have 10 psi of wastegate spring, it doesn't mean the wastegate tension force is equal to its direct applied pressure from the exhaust gas at 10 psi. You can try to push against the wastgate spring and you'll see what I mean. It's very strong. However, you can block the 10 psi of air flow after the turbo easily.

When you have a stronger wastegate spring, it'll push the valve down longer untill the exhaust pressure can reach its opening point. This will allow the exhaust gas keep flowing to the turbo and spin it more. After the turbo, the pressure will also be increased from more spinning. That's more air and more pressure to the engine.

 

steve, thanks for the detailed explanation.

Bob actually answered my questions about his setup w/o a wastegate in another post, but it had been deleted. Hopefully one of the mods can maybe merge that post or re-open it.

 

Hey Steve thanks for the reply.
I don't have wastegates on the turbos. all the exhaust energy will go through the turbos.
I modified a wastegate and put it on the charge pipe.
I’m only going to regulate boost pressure.
Chris & I did a little research and found the Smokey Yunick used this to keep the turbos spooled better during shifts.
I'm sure this isn't the best for turbo life as it spools them harder.
We have been running this set up on a Prelude for a little bit now, and the Prelude is actually being driven a lot more then we thought, so far no problems. The system works really well.

I hope this explains the no wastegate thing a little better?

 

That's no problem, gents. As for the case the wastegate is installed after the turbo, you will have faster spool time so that's the big advantage, although the turbo lives will be much shorter. There's no free lunch. You may need good oil lubrication and heat vent. Your turbos will get hotter than normal setup. But I'd really this setup. That's too hardcore

 

Thanks Bob. I asked that question about controlling the boost on the intake side in the other post before it got deleted.

I've never seen it before.. But it really makes the engine bay clean and simple. Cant wait to see it running.

 

Thanks Guys!
Hey Steve I don't really know if the initial spool up will be any quicker, as a normal wastegate stays closed until boost is reached anyway, but during the run this should keep the turbo spooled hard with less lag between gears.

 

im really interested in seeing how the car will perform with no waste gate or whats going to happen to the car.

GL with you build..