Does it actually measure out to 38mm exactly?

I have one, but it measure out to 34mm.

 

you got jipped bro
JK I don't know

 

I believe Tial used to make a 34mm EWG. It used the same flange as the 38mm.

 

Will a 35mm wastegate be sufficient for 2560 at 8psi? Or will I encounter creep/overshoot?

Not sure if I should go w/ something bigger.

 

it'll be fine. I've run the 38 on my 2876R at low boost and it's solid.

 

What do you consider to be "low boost?" Regardless, I'm sure the 38 mm is quite big enough for most of us.

I checked the "technical drawing" on their website, but I guess they have a new SolidWorks draft sheet that doesnt tell every measurement it could. IIRC they used to have a plain black and white style one that did. Either way, I'm sure its 38 mm and the inlet and outlet flanges are identical.

I dont think TiAL ever made a 34 mm wastegate, but I could be wrong.

All of that said, I havent found a good reliable site or calculation on what wastegate size to get for an engine. A few "yeah, that'll-be-enoughs," but nothing solid.

 

Keep in mind that smaller turbos / lower boost setups need more wastegate to maintain boost because more of the exaust must be vented away in those setups and especially in a small turbo/low boost setup.

With that in mind, let me tell you about some of my experiences. First setup I had was 1.6 w/ gt2554 and integrated WG. It held the boost well enough at 5psi, though it would start creeping to 6 by redline. Above 5psi, it had no problem as long as I tuned my EBC correctly. My current setup uses a t3 60/48 and Tial 35mm wastegate. For a long time, I ran a 4psi spring and had absolutely no problems with boost control. It would ramp up to 4 and hold it flat to redline. Today, I finally put int the 15psi spring, and I am experiencing the same great control.

To sum it up, EWG rocks and the 35mm is plenty for your setup. OTOH, internal wg setups work just fine, but I never saw such flat boost as I do now on my current setup with my internal WG.

 

Sweet. Thanks for the replies.

Does creep/overshoot still happen w/ EWG during cold weather? How about hot weather?

 

Cant say how it works in the winter, but I can tell you that today in 100* weather, I had no problems maintaining 15psi rock solid, no overshoot, no creep, just great boost control.

 

running a purely mechanical boost control system (including wg) does vary a couple PSI from winter to summer just by the nature of changes in air density, but it's pretty minor. I think I make 9 in summer and 1.5 in winter.

 

ummm ... what? 9psi in summer and 1.5psi in winter? This has to be a typo, please clarify.

 

I just remembered that 38 mm could be the outer diameter, not necessarily the inner diameter.

TiALs are the only wastegates that I've heard NOTHING but good things about, and my personal only choice.

Note that a lot of boost creep can be eliminated by sourcing the boost signal between the intercooler but before the throttle body.