# 38mm wastegate good for 600whp?



## vr6turbo500whp (Apr 20, 2010)

I am currently working on a 600whp vr6 Turbo set up in my 92 Jetta. I have been reading about wastegates and I have been wondering if my wastegate will be enough. They say with big turbos (high boost) run a small wastegate and with big turbos (low boost) run a bigger wastegate. Now is this true?

So my question is should I upgrade the spring inside the wastegate?

Or should I buy a 44mm wastegate?

My goal is 600whp. 

Set up:
Fully built 3.0L From head to bottom
PT6765 T3 .81 a/r 


Here's what I have been reading. 

http://en.wikipedia.org/wiki/Wastegate

Thanks for your input.


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## MaxVW (Nov 4, 2004)

bigger wg for more power


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## TBT-Syncro (Apr 28, 2001)

vr6turbo500whp said:


> They say with big turbos (high boost) run a small wastegate and with big turbos (low boost) run a bigger wastegate. Now is this true?
> Here's what I have been reading.


this is correct.

and your hotside is going to be small for your HP goals.


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## Dub-Nub (Sep 27, 2005)

TBT-Syncro said:


> this is correct.
> 
> and your hotside is going to be small for your HP goals.



to add to what TBT-Syncro said, when you run low boost you need alot more air to bypass the turbine whereas high boost less air needs to escape the turbine wheel, hence needing a bigger wastegate to make sure enough air gets bypassed.


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## Richard_Cranium (Mar 28, 2010)

yup, Dub-Nub has it right. larger WG for better control down low..... some of my honda race buddies dont even use a WG.....


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## vr6turbo500whp (Apr 20, 2010)

So should I keep the 38mm wastegate and just put a bigger spring in. 

Also TBT what would be a good hotside for my power goal. T4 .96 A/R? 

Thanks for the help guys.


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## radoman57 (Jan 16, 2007)

T4 .81 would be a good setup 
I had the T4 .96 on my pt6776 and it was kinda laggy, full boost at around 5500rpm
the .81 is around 4500 rpm


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## Dub-Nub (Sep 27, 2005)

vr6turbo500whp said:


> So should I keep the 38mm wastegate and just put a bigger spring in.
> 
> Also TBT what would be a good hotside for my power goal. T4 .96 A/R?
> 
> Thanks for the help guys.


You may be better off going with a slightly larger wastegate. 38mm may be good on a 1.8L but with a 3.0L that flows alot more gas it may not be sufficient. 

Find out how much boost you are going to run to achieve your power goals also.

What you could do is get a larger wastegate connection at the exhaust manifold and get a custom plate created that will do a 38mm to bigger connection so you can use the 38mm wastegate to see if it will hold up.


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## TBT-Syncro (Apr 28, 2001)

vr6turbo500whp said:


> So should I keep the 38mm wastegate and just put a bigger spring in.
> 
> Also TBT what would be a good hotside for my power goal. T4 .96 A/R?
> 
> Thanks for the help guys.


t3 1.06 or t4 81 (or whatever the 35 housing in that range is). *3782 would be worth considering too.

with a t3 .82 i can make boost at 2000 rpm, with 'real' boost well below 3500.


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## TBT-Syncro (Apr 28, 2001)

Richard_Cranium said:


> yup, Dub-Nub has it right. larger WG for better control down low..... some of my honda race buddies dont even use a WG.....


go old school and just run a small exhaust to control boost levels (corvair style).

i've also heard about guys controlling boost off of exhaust pressure, which i think is a pretty cool way of doing it.


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## Big_Tom (Aug 19, 2007)

rock a 44mm wastegate just to be safe man. it will be way less of a hassle to throw on a slightly bigger one from the start. screw swapping out wastegates after you get the car together :thumbdown:


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## vr6turbo500whp (Apr 20, 2010)

Big_Tom said:


> rock a 44mm wastegate just to be safe man. it will be way less of a hassle to throw on a slightly bigger one from the start. screw swapping out wastegates after you get the car together :thumbdown:


I was thinking about getting the Precision 39mm wastegate or the 46mm one. Does anyone have experience with Precision wastegates? They are cheaper then Tial and they come with more springs so you don't have to waste your money on buying bigger springs.

Thanks for the help guys.


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## zwogti (Jan 11, 2004)

Tial 44mm, 650WHP 550WTQ and no problem


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## Big_Tom (Aug 19, 2007)

^^^ There ya go


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## zwogti (Jan 11, 2004)

vr6turbo500whp said:


> I am currently working on a 600whp vr6 Turbo set up in my 92 Jetta. I have been reading about wastegates and I have been wondering if my wastegate will be enough. They say with big turbos (high boost) run a small wastegate and with big turbos (low boost) run a bigger wastegate. Now is this true?
> 
> So my question is should I upgrade the spring inside the wastegate?
> 
> ...





^^^^^ T3 back hose may be a problem for a 3.0L vr6 to get 600WHP, kind of small for 600WHP, boost may come in too strong on your gears, so far my last version straight cut APTuning gears are holding but now thinking on selling the tranny and some parts, I'm thinking on doing something different.


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