External wastegate questions!

R

RO_SUNNY

Active Member
Hi.

As some of you know I've decided to go with the external wastegate.
So ...until now I have welded a external wastegate conestion pipe on my manifold and blocked the internal wastegate.

But now I don't know how I will do with the external wastegate.
What size should the wastegate be 38, 40 , 44 mm???
What spring setting should I use?

Please advice you guys because it seems that I solve a problem and bump into another!

Cheers,
Bogdan
 
T

Tim

New Member
This isn't a problem, more a question of getting what's right for you.

I can't answer your question about size, but get a spring rated to the lowest boost pressure you want to run.
 
Empty Pockets

Empty Pockets

New Member
A 38mm or 44mm would be fine, personally i would get the biggest wastegate you can fit mate, you will have no problem running an over-sized gate, unlike if you run an under-sized one, plus if you upgrade turbo's or switch cars you will have more options to re-use the wastegate, As already said mate, the spring you choose to use will determine the lowest boost presure the wastegate opens, you are obviously going to be using a boost controler of some sorts to achieve 1.2bar so i'd go for a 14.5psi spring, if you're not going to use a controller then fit whatever psi/bar spring you want to boost too. Hope that helps mate.
 
watoga

watoga

Member
Hi Bogdan,

Is a 38mm external wastegate bigger than the stock internal wastegate on a 3071RWG? I would have thought so. Therefore, unless you plan on running HUGE boost, I'd stick with a 38mm external wastegate. Apparently there can be issues of larger external wastegates not holding low-boost consistently.

Dave
 
M

Makaveli_se7en

Member
To work out what size wg is needed you need to know the about of flow you want to gate. Then assume the wg orifice to be choked ie mach number = 1, then you can calcuate the area and hence diameter required.
 
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