kamAccord

How is the wastegate size determined for a turbo application? I'm attempting to produce atleast 400 whp with an H22 street applicaation and I'm trying to determine what size Tial wastegate to purchase.

Thanks!

adictionbass

There seems to be alot of theory behind it, but the one i have come to understand is the higher the boost, the smaller wastegate you can use. The lower the boost, the bigger gate you want.
This comes from the fact that at high boost (more pressure) X amount of air can go out a smaller hole faster than at a lower pressure. To release that same amount of air at a lower pressure, then you need a bigger gate.

SE-Rawkus

^^^Makes perfect sense only if the wastegate was fully compressed. Remember, a wastegate is constantly moving (up & down)...this is how it regulates boost. If it stayed open...the flow can be too much and lose some boost because too much exhaust gas is being released.
You want to choose a wastegate that can flow as much exhaust as possible when matched to a certain turbo. Imagine having a T78 with a Tial 35mm It wouldn't be able to flow at high boost levels...Boost Creep City

That is also a reason why once in a blue moon you want to replace your wastegate spring because the metal actually because fatigued over a long period of time.

Gravy

well thats not true. if u want to boost 50 psi on that t78 and dont want to release alot of the gasses u can go with a smaller wastegate......rosado racing is pushing 53psi on their corolla using a 40mm hks standard making 1000whp.

SE-Rawkus

ah...due to that excessive boost...their only real option is to run a smaller gate since most EBC's, if not all, can only regulate to 43.5psi. Well, atleast my new Greddy Profec Type S can only regulate to 43.5psi