Ok here's what I think I know...external wastegates bleed away excess boost. so if you're only boosting 10psi and your turbo spools and puts out 15, your wastegates routes 5psi into the dumptupe which goes into the exhaust/atmosphere. Also, if you have a 5psi spring inside your wastegate, then the lowest your can boost is 5psi?? I know that doesn't sound right, someone please correct me.

Anyway, I need to know what's the difference between the 38, 44, and 48mm Tial wastegates. 48 sounds like overkill for my goals, but I'm worried that 38mm might be too small. I'm not sure if the size is supposed to correspond with the amount of HP your making/aiming for or what. For additional info...

Goals - 350hp on a b16 with room to get to 400 if possible, BROAD TQ band. have no idea which turbo yet. i don't know if that's neccessary info but if you need anymore let me know.

 

Try to think of it this way,

The more boost you make, the more exhaust you make, which makes more exhaust, which makes more boost, etc. etc. All the wastegate is is a valve that opens when you hit your desired boost level and allows the gases to flow around the turbine, instead of through it. It has to be able to flow enough gas to let the turbo slow down so if it doesnt, then you get boost creep where boost levels slowly grow if the car remains under boost. Its not really a matter of getting 10psi here, throwin away 5psi there, more or less having the turbo flow at the boost level you choose constantly. The wastegate controls how much boost your turbo makes, your turbo doesnt make a certain amount of boost and THEN expect the wastegate to dump it.

As far as what size to get, depending on your boost levels you should choose what size accordingly, I have seen 35mm's on high horsepower cars, but then again bigger is sometimes better. Get a little more precise with what your setup is going to be, and Im sure the right size wg will come to you.

Props to a fellow b16 soon to be whipping some ass, keep us updated on this project Im sure theres more b16 fans who would love seeing this kinda power coming from the motor. Happy boosting

 

so the wastegate opens BEFORE the exhaust gases reach the turbine? meaning it allows the proper amount of gases through first, then dumps the rest? if that's the case then how does it know how much gas is needed for the specific turbo to get to a specific boost level? goddammit I'm still confused...

 

there is a spring inside the wastegate.... if its a 10 lbs spring then it opens at 10 lbs...it diverts the flow so that controls how much boost the turbo makes............350 seems like a lot of hp, are you ready for how expensive it will be?

 

The wastegate corresponds to the turbo. In plain ole' terms, the wastegate determine the boost. (actually you do) But its harder to explain....vacuum and other stuff plays a role too. The gate is closed until you hit the boost level you have set, the air tells the gate when it gets to that level then the gate opens a certain amount to keep the turbo going at the same speed so your boost level stays constant. etc.

Anyways about the wastegate to choose, I think 35mm 1-7 psi, 38mm is go to 7-15 psi, 40mm is 15+psi. Im pretty sure thats how it breaks down. I wouldnt worry about getting any bigger than 40mm anyways. I personally liked the Deltagate myself.... but TiAl definately is better quality everyone seems to think.

Check this out anyways:

http://www.turboneticsinc.com/wastegates.html

 

yes..I won't be doing it all @ once. I'll make my way up

 

Buy a tial specifically for your manifold. Most manifolds now days are ready for 38mm tials.

 

that does not answer my question.

 

Yes it does, buy a tial 38mm & have a nice day.

 

hahahaha...................