Hey guys,

I am running a Vortech s/c with the 11psi pulley. I've installed a wastegate designed to bleed off any boost over 9psi. Wastgate is mounted right after the blower and is a Turbosmart. I'm using a manual boost controller from TurboXS to control boost.

Here's the problem, when the boost hits 9psi and the gate opens it's allowing too much boost to escape. Boost hits 9psi then falls to 6 then slowly creeps up. The guy who owns the dyno shop I was at said I should use a electronic boost controller to control the wastegate better. I am only using the top connector on the wastegate currently. From what he says the electric boost controller will open and close the wastegate depending on the settings. Does anyone have an opinion on the difference? I feel it makes sense that you are using the boost to control the wastegate not just open it. I am loosing 20-30 hp I believe because of this. I'm not sold on spending another $500 to try this setup just yet.

Help...

 

did you look into reducing the size of the hole that vents the boost ? So it doesnt dump so much at once

 

When I got the car on the dyno I saw the plunger open and it opens very slow. I feel I would need a pin-sized hole to correctly trap air. I'm concerned that the R&D process would be dangerous. Too small and boost spike. Then again guys are running the 2.87 with success now. Looks like DFW is running it and only pulling 4 degrees of timing at 11psi. EEEKS. I'll get my dyno posts up, you can see the hp climbing towards the sky then down to 345ish. I peaked at 365hp at 5900rpms, but the last 800-1000 hp only see 7psi. On a positive note, this may be a safer setup.

 

I dont know why the Grubb cars get away with less timing . I know he uses a knock sensor when he tunes them . But if you could start with a very small hole and then just drill it out a little at a time , untill it dumps boost at the right rate . It really shouldnt take that many runs .

 

From my understanding an electronic boost controller is better and has more control. RSX8600 had a manual one but when Jotech was tuning they told him to go with the electronic one...wow what a difference! I know it's an RSX but 300 hp at 9 psi. Just my 2 cents worth. Our hobby isn't cheap. Good luck. Someone has to pioneer ahead.

 

I guess us Grubbs guys are lucky - for the moment. Please note I am using the 9lb setup but I am getting spikes up to 10.5 and stopping it with timing retard of 20deg at 11lb.

 

Look at your map again my friend...

 

I have.. I just have not updated my web site yet.

 

Can you post a picture of this wastgate SC setup?

 

Ive seen your recordings on your r4 but I cant remember . At what rpm does the WG start to open ? If you ran it to the point it opens and then just far enough further in the rpm range to find out if to much boost was dumped or not enough . Say it opens at 5,000rpm and run it only to where [ on your recordings ] you seen it go to far . Your BOV should take care of it when you let off the gas . Let us know what you decide to do and how it turns out...BIll

 

Here's a view of my recording

RPM in Red
Boost in Greed

 

 

Again

 

OMG

 

 

I think what I suggested is doable . Boosts realy drops off . I would weld a plate over the port , with a 1/4 inch hole in the middle . It looks like it opens at 6,000rpm . If you just run it to 6,500rpm you'll be able to see if it dumps to much or not enough .If you put in you timing wall while you do the RD on it . It can be done safely . If it doesnt dump enough...open the hole up slightly .You can keep an eye [some one else..passenger ?] on the boost to make sure it doesnt go to high...but I dont think it will be a problem...bill

 

I'll try it...I'll just get a flange that bolts to the wastegate output like you said. I'll keep you guys posted on the progress....or lack of! Thanks for the help Bill.

 

Don't most wastegates have different spring sizes?

 

Yes they do, but when it opens is not the problem. It's how it's opening. The sping sizes are rated by PSI

 

Finally found some time to play with this boost issue. I'm glad to say it's solved!!!! I used my air compressor to simulate boost in the system. What I found was that the boost controller was very slow to react and it was causing the waste gate to open and close very slowly. I know this is not the correct way to use the two devices, but it was worth a try at the time. If you scroll up you can see my old R4 recording. My new one is attached. This is now a true beauty with the 11psi pulley. Notice the boost is very linear from about 4800RPMs and up. Very similar to what a turbo will do. The only thing in the system now is a 11psi pulley and a Turbosmart waste gate with a 8psi spring. The peak you see is my wheelspin (awesome). The car is so much more responsive under boost, and the midrange is worlds above the 9psi pulley. Vortech guys compare your RPM vs. boost at the indicated mark in the recording. 5000rpm @ 6.8psi, the 9lb pulley will be like 4.5 or so at 5000rpm. And with this setup you're not even reaching 9 psi, you just have higher boost sooner where the torque is made.