Help: Wastegate setup with compounds

[chevyburnout1]

I'm curious on how everyone is controlling their wastegate with compound setups. I feel like my setup is very cheesy and 'Cummins-ish' and could be done a lot better. Been trying to dial in the setup and I just can't seem to get a happy set spot.

I have a Precision external gate with the two ports. When I bought the kit it only had two springs in it, from which I tested open up roughly around 5-7psi. I installed some washers to bump up the pressure roughly as Precision wanted $50+ per spring and were not very nice on the phone. So now just spring pressure it will open around 18-25psi. I then have manifold boost pressure being fed into the top port to emphasize keeping the valve shut. On that boost line I have a tiny adjustable orifice with a small regulated bleed after the orifice. The bottom port of the gate is just vented.

My understanding is with the orifice completely open, full boost and the spring pressure will be trying to hold the valve closed, where-as the drive pressure will be trying to force the valve open. I have a drive pressure gauge but I assume the actual pressure working against the valve would be manifold drive pressure minus hot pipe drive pressure. Now when I shut that orifice completely total boost drops but the LP charger rises, along with EGT's. So I know it's operating the valve.

My main question is, I feel like that orifice is not a good way to control the gate. Minuscule changes with the orifice make drastic changes with the charger control. My understanding is you want the high pressure charger spun up as fast as possible and then the gate should open to keep the charger spinning in it's efficiency range. I feel like the regulated orifice does not do a correct job with that. Am I over-thinking this? I've been thinking an actual pressure regulator like for an air compressor would be ideal, but they are huge and bulky. Are there small car versions? Should I invest in a fancy electronic boost controller? What about utilizing drive pressure only to control the gate? I've already grenaded my small charger once so I want to make sure everything is dead on correct.

Sorry for the long post haha. Been a long weekend and I think my mind is fried a bit.

 

[S Phinney]

I worked on setup for quite a while. I tried most everything that guys suggested. I finally tried what Turbosmart said and it works like it is suppose too. It goes against what most all diesel guys say as well. They told me to run maximum spring pressure for my gate which is 33 lbs if combined spring rate. Using the manual conto let from them apply total boost pressure to the lower port and vent the top port. It works just like they explained and I can control the boost from one end if the scale to the other. I didn't believe them NJ UT said what do I have to loose. Glad I tried their way out.

 

[chevyburnout1]

That's understandable. I originally did run full boost into the lower port of the wastegate but noted no difference if I ran it with or without. So I left it disconnected. With how high I can get drive pressure I figured I didn't need any more force trying to open the gate haha. After messing with it more today and doing more research I feel like I need an actual pressure regulator which will actually let only a set pressure to hit the top of the gate and that's it. I assume my setup now, with the bleeding orifice just creates a lower pressure differential from total boost, but still allows a linear pressure to be built on top of the gate with the actual pressure getting higher and higher, which is counter-active.

 

[chevyburnout1]

Basically to sum all this rambling up, do I just need a pressure regulator, say for an air compressor, in place of my cheesy bleeder/orifice setup? And then run full boost into the lower port of the gate? Should I spend the money and get all the springs that Precision has available for my gate?

 

[S Phinney]

I tried everything. Finally doing what my waste gate manufacture said worked. How much spring pressure can you get for your gate? I would get the springs for at least 30 pounds and regulate total boost to bottom of the gate.

 

[chevyburnout1]

It's looking like I can get enough springs to hit mid 30's. What contraption are you using to regulate total boost reference to the gate?

 

[Chevy1925]

Basically to sum all this rambling up, do I just need a pressure regulator, say for an air compressor, in place of my cheesy bleeder/orifice setup? And then run full boost into the lower port of the gate? Should I spend the money and get all the springs that Precision has available for my gate?

i would. i had what you are talking about dustin and it was a pain to set on my small turbo. seemed like there was no inbetween, not to metion when i did get it right, the motor vib would cause the adjustor to move and change boost. i put a small 5-150psi regulator on from mcmastercarr on that delong recommended and it was much easier to set and it locks into place once set.

i would do this as well as try what S Phinney is talking about

 

[S Phinney]

It's looking like I can get enough springs to hit mid 30's. What contraption are you using to regulate total boost reference to the gate?

I used a manual controller from Turbosmart. It has a rachet action click so it stays where you adjust it. Cost about a hundred bucks for one. Most use cheaper manual controllers but I wanted matching components.

 

[chevyburnout1]

Thanks for all your help guys! I'll order up a regulator right now!

 

[chevyburnout1]

Got the regulator installed. Working flawlessly! However I had to install it on the bottom port of the gate due to, I believe, the lack of spring pressure I have with only two springs. With full boost on the bottom port it would push the gate open regardless of pressure on top. So with regulating the bottom port it is working very well!

 

[Chevy1925]

Good to hear Dustin!

 

[Yellow Jacket]

What if you run drive pressure to bottom side of gate and boost pressure to top side of gate, with lighter spring like 5 lbs, when drive pressure exceeds boost by 5 lbs gate will open....

 

[S Phinney]

Got the regulator installed. Working flawlessly! However I had to install it on the bottom port of the gate due to, I believe, the lack of spring pressure I have with only two springs. With full boost on the bottom port it would push the gate open regardless of pressure on top. So with regulating the bottom port it is working very well!

I was told that with that setup it would work up to three times the spring pressures. That us how a I am running mine now and it us working the best that you could get it. I have a full range if control when it comes to pressure splits.

 

[chevyburnout1]

What if you run drive pressure to bottom side of gate and boost pressure to top side of gate, with lighter spring like 5 lbs, when drive pressure exceeds boost by 5 lbs gate will open....

If I was to run it that way my gate would open almost immediately as soon as the chargers would start creating boost. Drive pressure on my setup runs about 1.4:1 to 2:1 depending on fueling and where I set the gate.

I have debated on running drive pressure to the top of the gate thereby partially canceling out the drive pressure against the gate trying to open it. Then run regulated boost into the bottom port. But I feel the setup I'm running now will have just as much control as needed.