Car:
KYTP kit with pt7675, 46mm Precision wastegate, 3 inch dp open

On the dyno yesterday, the car creeped to 12 lbs and we shut it down. That was solely on the gate itself. We started with a 4.5lb spring and went up to 7.5lb spring. It creeped very bad on both springs.

My tuner called precision this morning, and they seem to think it is the way the wastegate/merge was made that is causing the creep problems. Attached is a picture. Any suggestions?

We are about to take the wastegate completely off the car, and see if the car makes any boost at all. If it does...then the placement of the wastegate is the problem.

 

I would definitly change the gate position, exhaust would have to flow backwards to flow into the gate. If you can try to go 90* to the merge or even better angle it the other way a tad if possible.

Or even make a merge off each 2.5 pipe to the wastegate.

Jay

 

Yep, gate position is TERRIBLE.

 

How far back does dp go?

 

Must be the gate location. My JGS40 controls the same turbo on my car just fine.

 

S488, on3 60mm wg, 4" dp to dual 3" quad cme.
With there 6-7psi spring I get 5# off the gate and the merge I made is nothing fancy.

 

If you have a good reference from the intake or compressor housing and the wastegate is functioning properly it is the wastegate location.

 

yeah its the location. the least amount of angle the better. Mine is at a 90degree (not ideal) from the flange, and has a 1/2" stub pipe coming out from the merge, so its really close to the point with the highest backpressure. I have zero boost creep and by boost cure is perfectly flat up top.

You have almost 180degree angle!

45 degrees or less would be ideal.

 

The DP dumps right at the starter. Spoke to Josh earlier at KTYP, he suggested putting some exhaust on it or adding a bigger wastegate. I guess we will see. Thanks for the suggestions. The car made some good power though. Was nice to see it make a small pull after it being down for a year.

 

more exhaust is adding more restriction post turbo, which might help the wastegate open sooner due to increased backpressure pre-turbo. Thats just a crappy bandaid. A bigger wastegate might help, but why buy a $500 WG when you can cut off the old flange, and weld in a new short pipe for $20 worth of materials.



This is a good reference when chosing WG size:

Big Turbo/Low Boost = Bigger Wastegate
Big Turbo/High Boost = Smaller Wastegate
Small Turbo/High Boost = Smaller Wastegate
Small Turbo/Low Boost = Bigger Wastegate

 

As said before, its the wastegate merge. its bad!

Here vvvvvv



Edit: Killer you beat me to it

 

I'm thinking gate position too. But I know he's been building these for years so Idk. I have a TC78 & Tial 44mm gate. They worked fine on my cheap ebay kit but when I switched to a KYTP manifold kit, I'm seeing 11 lbs with a 7 lb spring. Mine looks about the same as yours except it goes toward the passenger side instead of down. My exhaust is dumped at the axle with a Dynomax bullet muffler.

 

I see a lot of cars with this exact set up, not to sure. Any updates?

 

Why spend $500 on a wg when the on3s 60mm are $200 and work flawlessly

 

https://ls1tech.com/forums/forced-in...-w-pics-2.html

Some people get by with this setup, I for one did not. You can see what I did.

 

I had never even heard of on3 three years ago when I bought my Tial

 

260+ manifold setup's built in the last 7 years. Been done multiple times by half a dozen or more other shops and DIY builders.

I have seen the boost creep issue 3-4 times. With this same combo. Mind you this is 3-4 times out of 70+ setup's with the same combo.

The WG is positioned in the highest pressure point of the merge. The angle is not the best but is the best angle that fits the setup the way it was built. We all know there are better ways to do everything. There is not a lot of room in a 4th Gen F-Body to do them though.

I have talked to Andrew about the boost creep. Offered some suggestions and such.

 

Still waiting to see what we are going to do....Pretty much don't give a fXXX...just need the car done.

 

At such a low boost level it's hard to imagine the gate location is the problem.

Are you sure the w/g is plumbed correctly, and have you visually tested the w/g to ensure it does open ?

Have you tried blowing boost pressure only into the port closest to the manifold ? Ignoring the top port for now.

bottom port = blows it open
top port = blows it closed.

Most instructions do tell you to reference both, but try bottom only first and see what happens. After visually testing it to ensure it does actually open of course and what pressure it requires.

 

top port is to atmosphere.....bottom port is referenced to the turbo....other bottom port is closed.