Boost control???
12-20-2001 | 04:40 PM
#1
Thread Starter
Burning Brakes
Joined: Oct 2001
Posts: 1,202
Likes: 1
From: Canada
Boost control???
I've been having a hard time controlling the boost on my 951 with my manual boost controller and the stock wastegate. I would turn the dial the tiniest bit, and the max boost would go up from around 16 psi to over 20 psi. Derrek at Huntley Racing told me it was because of the stock single-port wastegate, and I bought a Deltagate Mark 2 to cure the problem. The wastegate is being installed today, and the turbo-god who's doing the install called me up and is wondering if perhaps the cart is going before the horse, so to speak.
He figures that I should have bought an electronic boost controller instead, and used my stock wastegate with it. Has anyone tried this? How well does it work, or do you really need a dual-port wastegate to control boost properly, even with an electronic boost controller?
He figures that I should have bought an electronic boost controller instead, and used my stock wastegate with it. Has anyone tried this? How well does it work, or do you really need a dual-port wastegate to control boost properly, even with an electronic boost controller?
12-21-2001 | 01:51 AM
#2
Race Director
Joined: Jul 2001
Posts: 14,075
Likes: 3
From: Santa Barbara, CA
Well Ian, don't know if it's too late, but here's my take on the whole wastegate issue...
Typically it's really not the wastegate. Common mis-interpretation by a lot of the "expert" tuners out there. That's because they all use manual controllers with no variable-control mechanism. The issue is that you need a feedback loop with the wastegate due to the fact that the control is based upon TWO factors. Aside from the input boost-level controlling the wastegate diaphram, you also have exhaust pressure on the wastegate valve itself. The SUM of these forces then control wastegate behavior. So as the RMPs rise (and exhaust pressure increases), you have to bleed off the signal going to the diagram to maintain the same wastegate opening. That's why a manual controller will always bleed off boost at high-RPM, it doesn't know to dial back the control signal to maintain a flat boost-curve.
Only an electronic controller with fuzzy-logic and memory and learn the behavior of your wastegate/turbo combo. And they can utilize different boost-control signals in different gears to give you the same boost level in all gears and all RPMs (provided your turbo can generate it).
That said, there's a ton of people getting max-boost all across the board with big turbos and the stock wastegate. As a sure thing, I'd shim the stock wastegate anyway, since it only takes 30-minutes:
Typically it's really not the wastegate. Common mis-interpretation by a lot of the "expert" tuners out there. That's because they all use manual controllers with no variable-control mechanism. The issue is that you need a feedback loop with the wastegate due to the fact that the control is based upon TWO factors. Aside from the input boost-level controlling the wastegate diaphram, you also have exhaust pressure on the wastegate valve itself. The SUM of these forces then control wastegate behavior. So as the RMPs rise (and exhaust pressure increases), you have to bleed off the signal going to the diagram to maintain the same wastegate opening. That's why a manual controller will always bleed off boost at high-RPM, it doesn't know to dial back the control signal to maintain a flat boost-curve.
Only an electronic controller with fuzzy-logic and memory and learn the behavior of your wastegate/turbo combo. And they can utilize different boost-control signals in different gears to give you the same boost level in all gears and all RPMs (provided your turbo can generate it).
That said, there's a ton of people getting max-boost all across the board with big turbos and the stock wastegate. As a sure thing, I'd shim the stock wastegate anyway, since it only takes 30-minutes: