I recently pulled my s480 off an installed a pt98 in a front mount position an I ran into problem with the wastegate placement. I did something that I seen a few others do and it did not not work for me. I had a race to go to this weekend and didn't really get to compete because of I'm assuming was boost creep. I have a jgs 60mm gate with ams500 and co2, with the controller set at 1 1stage and 1 on second stage, it left on 6psi , made about 12psi at the 1/8 mile and 27psi by the end of the run. It should have only been 6-7 psi since I have the lightest spring in the gate. We tried all kinds of things, checked all the hose routing and nothing would control it. We vented the top port on the gate so it would run off spring pressure and it left on 5 and made 18psi at the 1/8 and I aborted the pass.

I only have pictures on my phone and it won't let me post them. Here is a YouTube video that you can kinda see the wastegate placement on the passenger side of the truck.

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I dont see a way to get it in there with it set up like this. I'm think I am going to redo the hot side pipes and put 2 smaller gates so I can controll both sides. Would 2 40mm jgs gates work well like this?

 

Re: Wastegate recommendation

You would be going down in gate size by a small amount, couldn't keep the gate on top behind the Y pipe?

 

Re: Wastegate recommendation

ok, here are a few pictures of what im working with.

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Re: Wastegate recommendation

Whats easiest for you - reworking the hotside prior to the turbo or covering the hole where the 60mm gate is currently and adding a 40mm gate to each of the 90's before the hotside heads toward the turbo? I had a 5 into 1 collector on my first setup that did exactly what yours is doing and by adding a 38mm gate to the 90 on just ONE side I was able to control boost all the way down to 5lbs.

It seems the simplest fix would be gates on the 90's a ways from the turbo.

 

Re: Wastegate recommendation

The pass side bank is going straight into the turbine regardless of the gate and the driver is at an angle that should work better but the gate is so far that I'm guessing that with everything going on it all goes right past your WG tube inlet.

 

Re: Wastegate recommendation

here is how the gate was on the s480 and it worked great like this and imo, this was a worse piping design, but i could control it down to 6 psi just on the lightest spring

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Re: Wastegate recommendation

Same thing happened to me.... My first turbo was a Master Power which had more back pressure and I could control boost just fine. I switched to a Precision 76 GTS and couldn't control boost at all....

 

Re: Wastegate recommendation

That huge turbo is probably all over 1-1 boost/backpressure, that makes the angle of the gate very important. Id leave the big gate on there and throw another on the driver side as mentioned, it would be the easiest thing to do. New setup looks sick man!

 

Re: Wastegate recommendation

ok, so if i put a second smaller gate on the passenger side pipe, would i plumb that in with the co2 from the other gate? would I need ~equal sized springs in both of the gates? I have never ran 2 gates before and Im not sure on how i would control 2 different sized gates.

 

Re: Wastegate recommendation

I would T the c02 into the second gate as well, granted that's not how I would build the system first time around but it would be letting you vent more exhaust around the turbine without having to redo the whole hotside, yes they're different sizes but you dont have a dedicated twin scroll setup so taking pressure/exhaust out doesnt make a difference. And please don't take me as an expert opinion, I have one turbo build under my belt and actually read a lot of your stuff on pushing the lt1 block.

 

Re: Wastegate recommendation

Im not sure what im going to do right now. I might reclock the exhaust housing and go a different route with all the pipes. i was headed a different direction with it but did not have all my other parts in like the radiator and stuff so i went safe and did it this way so i knew i would have room. I think i may go with a single 3.5 in pipe into the turbo and merge both of the hot side pipes into that 3.5" pipe.

 

Re: Wastegate recommendation

May do better just mounting the gate right to the side of the pass. side hot pipe. its still an open plenum and will feed the gate MUCH better than on the end of a long pipe.

 

I just decided to redo the hot side the way i wanted to do it in the first place. I have all the hotside done except for the wastegate placement. Here are a few pictures of what i have now and where I was planning on putting the gate. This looks to me like the exhaust will have a direct shot out of the gate. But will this cause a flow problem otherwise with the gate being in the bend and is it too far from the turbo?

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Hell yeah that looks textbook! If that doesn't work I don't know what will.

 

Your new routing of the hot side piping looks a lot better and looks like it will for sure help to improve or resolve your wastegate problem-Justin

 

distance from the turbo doesnt matter, and that gate placement looks great!

 

The gate won't be a restriction. When its closed, the exhaust is stacked up in the gate itself, making it "act" like its not there.

 

Looks great! Run it and let us know the results!

I agree with the above regarding flow - all pre turbine air should blow right past that when the gate is closed...