Wastegate Size

[s13drifter88]

I got asked a strange question today and it's been bothering the faqk out of me since . What is the wastegate diameter on the S15 28?

[float_6969]

??? why would someone ask that? Were they assuming you had an external wastegate? That's the only thing that makes sense. If they did think you had an external, they're stupid, LOL!

[s13drifter88]

I was talking about going external yes because I made a 38mm flange and extension tube in the machine shop today where I'm in college. It was just a strange question and kind of bothered me that I couldn't answer it lol.

[float_6969]

Why do you need an external wastegate for that turbo? There is a lot of mis-conception regarding wastegates floating around. The stock internal wastegate on the S15 T28 turbo will cover all of the possible boost pressure's that turbo is capable of producing. The main reasons for an external wastegate are for a turbo that doesn't have an internal, or you are trying to run low boost on a large displacement engine with a small turbo. Other than that, internal is fine and you gain nothing with an external.

[boost_boy]

Other than that, internal is fine and you gain nothing with an external.

Yes he will! A frickin' headache with trying to plumb the external gate onto the stock manifold or modifiying the stock turbo to use an external gate. As well as a noisy @$$ car to boot . Don't do it.........

[s13drifter88]

Idk, I found it a bit of an odd question myself but if left me wondering. I'm going external on mine but for an obvious reason. My talk on external wastegate size is what sparked it all

[r34 gtr]

The wastegate flapper thing is about 1" if I recall.

I dont know about anyone else, but my friends and I have had trouble with internal wastegates being too small to properly control higher boost pressures. I would always get boost creep on my s15 t28, and my buddy was having a hell of a time controlling 20psi on his td05h-20g until he went external WG. It seems like if you want to run an internally gated turbo at close to its maximum rated pressure, you need to just tune for maximum pressure because thats what you will be getting regardless. Tiny little WG flapper just can't vent enough gas to control boost.

[float_6969]

TIM'S ALIVE!!! OMG dude, where have you been all my.... last few months since I saw you post last?

[s13drifter88]

Wow 1", that's little lol (that's what she said)! I just found it an odd question to be asked. Never even though about it. It's a 28... who cares

[r34 gtr]

Yeah people are weird and can ask ridiculous questions. I probably wouldn't take tuning advice from that dude though.

Float, I have been on, I just havent posted much. Cruising the classifieds mostly, as my engine needs stuff to run again. I'm torn as to whether or not I want to put the engine back in the 240sx or into my e30, but its all moot since the engine is incomplete anyway. Also spending a dizzying amount of money fuelling my mountain bike habit. That doesn't do anything for my car habit.

[s13drifter88]

What all parts is yours lacking?

[r34 gtr]

Forged pistons, machine work, bearings, rod bolts. Just the usual expensive stuff. Also a drive shaft.

[s13drifter88]

That'll do it. I've noticed there's something about bills that slow down a project

[float_6969]

Well you need to get that isht on the road again man! All the other OG's are getting theirs going and you're a member of the club now!

[r34 gtr]

Ill get there. I am considering going back to school though, so if I do its going to be a while longer. No worries though man.