kasturbo

I know I'm being lazy by not searching this beaten topic, but here it goes. I'm tired of my Lindsey wg leaking off boost and have a buddy selling a Tial 38mm. Question is will this be too small or will I need to get the 46mm?

Thom

Yes.
No point for going bigger unless you have a big exhaust and anyway it's just a bypass valve.

kasturbo

Thom is that the wastegate that you are running?

JonH

You might be close Kevin, SFR lists the 38mm up to 400hp. Soooo, the real question is how much you got there?
http://www.speedforceracing.com/prod...wastegates.php

Thom

I currently run it on the 2.5 and I will definitely reuse it on the 3.0 when it's complete. Stock exhaust, by the way.

reno808

Well bigger is always better lol. If he is selling it for a good price than buy it and run it if not then get a bigger one

reno808

Jim runs a 38mm and he made 602

kasturbo

I'm a little north of that number depending on what I have the boost setup. Not sure if my issue is with the wastegate or not.

If I have the boost set to 18psi it will hit that psi and then immediatly role back 3psi. Never had this issue with the 2.5 with the same wg and boost controller.

DDP

That doesn't mean it's optimal.

How much boost are you planning on running? HP output of the motor? And you can't just look at a WG as "just a bypass valve".

kasturbo

I'll be running 15 to 18 pounds. 400 to 450 to the wheels.

Chris White

38mm is fine. You want to run the smallest gate that works - bigger is not better, bigger is less control!

kasturbo

Thanks Chris. I'll pick it up and give it a try then. Any idea if my issue sounds like a wg problem.

reno808

Oh i know I am not saying it is. I was stateing. He can run it with no ill effects

87944turbo

Sounds like it could be a boost controller problem, which one are you using?

Duke

I'm surprised by the many incorrect answers in this thread..
The HP rating is totally useless and just plain BS.

Yes, the wg is a bypass valve. The higher the boost the LESS gases to bypass.
That means..
Small displacement engine high boost = smallest valve
Small displacement engine low boost = small valve
High displacement engine high boost = larger valve
High displacement engine LOW boost = LARGEST valve.

In one perspective, the hp rating is the otherway around than usually stated.

On a 3.0l turbo running 0.8 bar boost, there will be a lot of exhaust to bypass and I would not run a 38 mm on that kind of engine. It will be sensitive to boost spikes at higher rpms and during fast shifts.
I've seen that on a 3.0l 8v engine with 38 mm valve.
Sure it will work, but I would recommend going with a larger valve.