The design of the wastegate is the most awful thing I've seen in some time. It's tiny, and the flap doesn't even open all the way. I'm grinding the crap out of it and putting a bigger plate on but has anyone customized it so the gate can actually open all the way?

What do you have to do to keep the actuator from blowing open too?

 

Try this from the archive:
https://www.rx7club.com/showthread.p...hreadid=125744

 

Just figuring out? Not exactly. I knew it was small and bad but I didn't know it was this damn small. Bear in mind I just got my turbo a few months ago and haven't run it yet...

 

OK, Snrub's initial triple post was by accident. The rest of your are just post ******. Thread cleaned up.

 

Yes the HT-18 wastegate is very small, but you can't have seen too many turbos if you're complaining about its basic design. All internal wastegates work essentially the same. The flap can only open as far as the back plate will allow.

You have to remember that once it's that far open, opening any further doesn't increase the wastegate's flow. Imagine putting your hand over the pipe of your vacuum cleaner. When you lift your hand off half an inch air starts flow, but moving it further away doesn't make it flow any more. Similar principle.
Did yours actually blow open? That's a very rare problem...

 

I didnt think that was even possible with a stock turbo, I was under the impression they don't flow anywhere near enough air to actually force the gate open.

 

I was just asking because if you've got the exhaust pressure coming out say doing X amount of course with the stock wastegate and then you double the diameter of the wastegate, you are opening up 4 times as much space. The force across that opening is going to be a force over the area. You increase the area by a factor 4, you up the force by a factor of 4. This question was to see if the wastegate has any problem holding this much force against it seeing as you're looking at 4x the exhaust pressure you were previiously at 10 psi.

Some other car people talk about this problem that some cars will have when you do too large of a port.

 

You're mixing up your terms terribly. What I think you meant was:

If you double the diameter of the wastegate, you have four times as much area. The force applied to the flap is going to be a pressure times area. You increase the area by a factor of four, you increase the force by a factor of four. This question was to see if the wastegate has any problem holding this much force against it seeing as you're looking at four times the force you were previously at 10 psi.

In reality this is not a problem, because at high boost the flap is open anyway. The worst that will happen is that the flap is forced open prematurely and the rate of boost increase will be slowed a bit. This is still unlikely and max boost will still be the same.

From your question I thought you were asking about the wastegate actuator actually failing, i.e. splitting open. That's why I said it was rare. Your terms were a bit dramatic.

 

yeah, my writing has gone down hill, it's been a bad day, sorry about that.