Spool improvement valve?

J

jgsturbo

caveman
Joined
Dec 26, 2011
Messages
483
All wastegates will crack open before they reach full boost. So how about an air operated solenoid to block the lift pressure from the wastegate(s) till a certain amount of boost?
spool_imp_valve.jpg

Would be extremely trigger like and maybe able to build that precious boost a few hundred rpms sooner? Very optimistic I know.
Opinions>>?
 
I'm not following. A wastegate can be set to open at a regulated amount of boost.
 
duck_04 said:
I'm not following. A wastegate can be set to open at a regulated amount of boost.
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Yes BUT being effected by the turbine pressure it will start opening well before the target pressure is reached which makes spool slower.
When we vent a wastegate to its own exhaust, its very obvious.
This device would offset that event till the last possible moment.

A lot of electronic boost controllers have a function that does this, this would be doing the same but mechanically.
 
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jgsturbo said:
Yes BUT being effected by the turbine pressure it will start opening well before the target pressure is reached which makes spool slower.
When we vent a wastegate to its own exhaust, its very obvious.
This device would offset that event till the last possible moment.

A lot of electronic boost controllers have a function that does this, this would be doing the same but mechanically.
Click to expand...

I would think that if we were dealing with low boost pressures, like in the gas world, the difference between cracking pressure and full flow would be a source of poor spool up. But when the wastegate doesn't start opening until 35+ psi, I would consider the charger spooled by that point.
 
There been some discussions about having enough spring pressure to make the gates respond better. Some have even gone to dmaxx valve springs. Turbine pressure does need to build before the turbo will make boost, that's a constant. That is why we use bp to control a wg. Also larger springs can be used if your using bp to help it open (vs set to open on dp alone). Which holds it tighter till bp arrives aiding spool. This device would hold the gate shut till the last possible moment.
Gas or diesel we are all trying to build turbine flow ASAP.
Wish I had a manual truck around to test with. Anyway to get an auto NOT to kick down? TV cable?
 
something like this? this has been around for a while and it allows it to restrict boost pressure to fool the wastegate and allow you to build more before the gate actually opens. if i am understanding your device correctly, it works just like the manual boost controllers thats already being used.

MBC.jpg
 
That boost controller keeps some of the boost away from the gate till a certain boost ... idk only thing I don't like is its strictly a blender style boost controller and with the setups I'm doing the ball would only get looser with more boost.
 
Tate said:
But when the wastegate doesn't start opening until 35+ psi, I would consider the charger spooled by that point.
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Yes.

You are trying to design an "automatic turbo barker". If you wait and wait and then dump the gate at once, you are going to break a shaft from reverse torque. No? I applaude your ingenuity, but I'm not conviced you are chasing something that will work. $.02
 
4x4dually said:
Yes.

You are trying to design an "automatic turbo barker". If you wait and wait and then dump the gate at once, you are going to break a shaft from reverse torque. No?
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Its not really anything so violent, The turbine will be gaining speed as if there wasn't a gate then when the device triggers the gate will POP out rather quickly. All the turbine will do is stop gaining speed then the gate will maintain speed. Worse that could happen is boost will overshoot the target IF the device is set to trigger too late. Reverse torque is largely non-existent, its completely masked by the inertia of the rotating assembly.
Barking aka Surging would be from if your turbine was size so small that its shoving the compressor in the bad part of the map, thats a turbo building error nothing to do with this device.

I applaude your ingenuity, but I'm not conviced you are chasing something that will work. $.02
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I know it will work, just what will be the worth? Will it be a huge improvement or will it be barely noticeable. I'm fine with either but unless its been proven NOT to work, I see no reason not to try.
 
thats why you tighten the spring and cause it to tighten and require more boost to open the gate. like mentioned before if you just pop open the wastegate it will relieve the drive pressure off the turbine and with the boost pressure on the compressor will cause it to "bark". that is what i understand from the reading i have done on here. the way i understand the wastegate is that it is supposed to fluctuate with boost pressure to maintain proper flow of exhaust and air without over speeding the turbo.
 
A turbo system is a turbo system and we're ALWAYS trying to design wastegates that work with trigger like action. This really has nothing to do with surge.
Surge (BARK etc.) IS a combination too little airflow and TOO much pressure. Whether or not the compressor surges on spool up is of not matter to the wastegate.
And if you sized your turbo so small (on the exhaust side) that it makes the compressor surge on spool, a WG the cracking open (pre-desired DP) early isn't going to fix or change it.

Wastegates just regulate the maximum DP to control the speed of the turbo.
The WG shouldn't be leaking anything before its set opening point.
That's all this device accomplishes.
 
Chevycummins said:
thats why you tighten the spring and cause it to tighten and require more boost to open the gate. like mentioned before if you just pop open the wastegate it will relieve the drive pressure off the turbine and with the boost pressure on the compressor will cause it to "bark". that is what i understand from the reading i have done on here. the way i understand the wastegate is that it is supposed to fluctuate with boost pressure to maintain proper flow of exhaust and air without over speeding the turbo.
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The only way you are going to bark a turbo by wastegate opening alone is if it is vastly oversized. It should be similar to rolling out of the throttle a bit to hold a constant pressure. I've never had an instance of turbo bark from a wastegate opening. Granted, mine have all been internally gated to this point, but my point remains.

What I understand Lance's objective is to reduce the differential from cracking pressure to full flow pressure by removing the opening pressure from the wastegate until its needed. But I would look at what the cracking pressure is on a wastegate when full flow is around 50 psig. If cracking pressure is 35 psi, is it really that detrimental to the system?
 
If cracking pressure is 35 psi, is it really that detrimental to the system?
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It will take longer to reach 50psi IF your losing DP @ 35psi. Even tho the PRs are lower on a gas engine it really makes a difference. And when considering the turbine RPM required to make 50+psi one would think it would be useful.
 
I used pressure switches that were adjustable from 14-75 psi, and tied in 12v, 3-way solenoids inline with them to work the diverter valve, and quick spool valve on my twins.
Pressure supply was off the secondary...

My back ground is Instrumentation...I know it works like a Hot Damn! I can pop the diverter valve or Quick spool valve open at any pressure I want.
 
jgsturbo said:
It will take longer to reach 50psi IF your losing DP @ 35psi. Even tho the PRs are lower on a gas engine it really makes a difference. And when considering the turbine RPM required to make 50+psi one would think it would be useful.
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I found the only video I have of my truck on a dyno with the gauges in view. I paused it at 30 psi, and again at 45 psi. The timer on the video was at 4 seconds for both. My estimated time between those two pressures is about a half second.

Would this valve noticeably decrease that half second? A 30% decrease is still 3/8 of a second between these two pressures. I must confess, this was on a 450hp truck with a 62mm single. With more fuel on my 66mm turbo, I would say this time was even lower. Just initial spool up was much longer.

I'm not trying to be argumentative here, it just doesn't seem like a place where our trucks fall short. On an engine that has a wastegate set for 10 psi, cracking pressure is 6 or 7 psi, then it seems more prudent when most turbos are very lazy at those kinds of PR's.
 
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