Electronic boost controller for centrificals?
Thread Starter
Burning Brakes
Joined: Jul 2004
Posts: 1,087
Likes: 10
From: Hernando MS
Electronic boost controller for centrificals?
Is there a way to have an electronic boost controller on centrifical blowers that would allow you to run a smaller pulley and have more low end boost ,yet would bleed off boost at higher rpm to keep the boost safe. I know ECS has mentioned a restrictor plate but isnt here somthing better or more sophisticated that would work off MAP pressure or RPM? Could a centrifical boost system be controlled the same as a turbo?
Melting Slicks
Joined: Apr 2005
Posts: 3,418
Likes: 1
From: Chicagoland Area IL
On paper, yes boost can be controlled. To start with inlet restriction such as ECS plate does work but with efficiency hit (picture plugged inlet air filter, sorry for bad comparison).
Ultimately you will always be better off choking inlet versus bleeding discharge pressure. You already consumed HP to turn compressor and bleeding is just like throwing away energy – not a good idea at all.
A variable inlet restrictor is best solution, but with small return. A centrifugal compressor is bound by certain rules, mostly speed squared (very oversimplified) but to get say 2 PSI of boost at idle is very unrealistic.
My take on LSx engines is you have enough bottom end power to overcome low boost of centrifugal compressor (ATI, Paxton and Vortech). If this is a big concern then look at KB or Magunson.
Mike
Ultimately you will always be better off choking inlet versus bleeding discharge pressure. You already consumed HP to turn compressor and bleeding is just like throwing away energy – not a good idea at all.
A variable inlet restrictor is best solution, but with small return. A centrifugal compressor is bound by certain rules, mostly speed squared (very oversimplified) but to get say 2 PSI of boost at idle is very unrealistic.
My take on LSx engines is you have enough bottom end power to overcome low boost of centrifugal compressor (ATI, Paxton and Vortech). If this is a big concern then look at KB or Magunson.
Mike
Drifting
Joined: Oct 2003
Posts: 1,923
Likes: 5
From: San Antonio TX
Originally Posted by Skunkworks
On paper, yes boost can be controlled. To start with inlet restriction such as ECS plate does work but with efficiency hit (picture plugged inlet air filter, sorry for bad comparison).
Ultimately you will always be better off choking inlet versus bleeding discharge pressure. You already consumed HP to turn compressor and bleeding is just like throwing away energy – not a good idea at all.
A variable inlet restrictor is best solution, but with small return. A centrifugal compressor is bound by certain rules, mostly speed squared (very oversimplified) but to get say 2 PSI of boost at idle is very unrealistic.
My take on LSx engines is you have enough bottom end power to overcome low boost of centrifugal compressor (ATI, Paxton and Vortech). If this is a big concern then look at KB or Magunson.
Mike
Ultimately you will always be better off choking inlet versus bleeding discharge pressure. You already consumed HP to turn compressor and bleeding is just like throwing away energy – not a good idea at all.
A variable inlet restrictor is best solution, but with small return. A centrifugal compressor is bound by certain rules, mostly speed squared (very oversimplified) but to get say 2 PSI of boost at idle is very unrealistic.
My take on LSx engines is you have enough bottom end power to overcome low boost of centrifugal compressor (ATI, Paxton and Vortech). If this is a big concern then look at KB or Magunson.
Mike
Le Mans Master
Joined: Jan 2001
Posts: 5,786
Likes: 6
From: Lafayette Colorado
Originally Posted by Skunkworks
A variable inlet restrictor is best solution, but with small return.
Keith
Melting Slicks
Joined: Apr 2005
Posts: 3,418
Likes: 1
From: Chicagoland Area IL
Originally Posted by kromberg
Hmmmm....... maybe something like a DBW throttle body between the intake filter and the inlet of the supercharger? The hamister is running in the wheel
Keith
Keith
A few suggestions – be careful of inlet pressure distortion (impeller eye or face does not like pressure distortion which can be a surge trigger or push surge line right) so keep valve several inches away from inlet. The system needs to be very fast responding, when you start closing valve a transient may develop in which you actually get a pressure spike (this can occur in a blink of an eye). Also consider fail safe operation, because if acts up your engine will likely grenade.
Mike
Le Mans Master
Joined: Jan 2001
Posts: 5,786
Likes: 6
From: Lafayette Colorado
Originally Posted by Skunkworks
I got one on the drawing board, but like I mentioned earlier the returns may not be worth cost and effort.
A few suggestions – be careful of inlet pressure distortion (impeller eye or face does not like pressure distortion which can be a surge trigger or push surge line right) so keep valve several inches away from inlet. The system needs to be very fast responding, when you start closing valve a transient may develop in which you actually get a pressure spike (this can occur in a blink of an eye). Also consider fail safe operation, because if acts up your engine will likely grenade.
Mike
A few suggestions – be careful of inlet pressure distortion (impeller eye or face does not like pressure distortion which can be a surge trigger or push surge line right) so keep valve several inches away from inlet. The system needs to be very fast responding, when you start closing valve a transient may develop in which you actually get a pressure spike (this can occur in a blink of an eye). Also consider fail safe operation, because if acts up your engine will likely grenade.
Mike
As long as the TB is placed before the MAF, I do not see how it would create a problem if it suck opened or closed. If it did stick closed, I think it would be very noticable right away, and the car can be shutdown.
Keith
Melting Slicks
Joined: Apr 2005
Posts: 3,418
Likes: 1
From: Chicagoland Area IL
Keith,
To start with, this topic is a little tricky. Although I have design about done on paper I won’t be testing for a few months. I’m working on a supervisory design that will keep engine from grenadeing/failing. This includes dual wideband O2 inputs and other variables that will monitor critical parameters to determine safe engine operation and take corrective actions.
The biggest problem with centrifugal designs is compressor map or basically speed squared relationship (over simplified). To get a little more bottom end boost, upper end boost gets crazy. I don’t want to give too much away, but variable inlet restriction is only sensible solution. Pressure distortion and throttle transients are two biggest concerns. The bleeding of boost pressure is very inefficient and temperature rise hit is huge!
I’ll PM you in next day or two with more info.
Mike
To start with, this topic is a little tricky. Although I have design about done on paper I won’t be testing for a few months. I’m working on a supervisory design that will keep engine from grenadeing/failing. This includes dual wideband O2 inputs and other variables that will monitor critical parameters to determine safe engine operation and take corrective actions.
The biggest problem with centrifugal designs is compressor map or basically speed squared relationship (over simplified). To get a little more bottom end boost, upper end boost gets crazy. I don’t want to give too much away, but variable inlet restriction is only sensible solution. Pressure distortion and throttle transients are two biggest concerns. The bleeding of boost pressure is very inefficient and temperature rise hit is huge!
I’ll PM you in next day or two with more info.
Mike
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