What Size Wastegate?

[Steve]

Hi,

Just wondering if anyone would have any idea what is the minimum size wastegate I should run with a HKS 3037S 56T?

Also anyone have any idea where I can pick one up for a decent price and how much I should expect to pay?

Cheers

Steve

[GTS-t VSPEC]

Hi Steve,

We have tended to use the 45mm wastegates, these seem more than ample for most applications. We have even run a 45mm with a T78 with no problems.

I think they retail for around $770, but it may be possible to pick-up a 2nd-hand one, just be careful that the spring it still stiff enough to hold the boost.

See'ya:burnout:

[G0DF4Th3R]

quick question, are they ppl running external wastegates on the stock turbos and is it possible and have they just wasted money etc?

[GTS-t VSPEC]

GODF4Th3R,

The factory turbo is fitted with an internal wastegate, and while it would be possible to fit a pipe and external wastegate on it there would be no benefit.

The factory manifold is not designed for an external wastegate, so this needs to be replaced when going for a bigger turbo. Some upgraded turbo's do come with internal wastegates, but the externally wastegated versions are considered far superior.

See'ya:burnout:

[G0DF4Th3R]

thanks for the info

since the factory turbo has an internal wastegate, is it possible to set boost from there and how is it done?

sorry for dumb Q's

[Steve]

Gday GTS-t VSPEC,

Thanks for the reply - out of interest, do you have any idea of the problems that would be associated with fitting an undersized wastegate?

G0DF4Th3R,

The factory wastegate (as all wastegates) is used for setting boost - thats its job. About the only exception I have heard to this (though there may be others) is a mob in Melbourne I think that use a BOV to regulate boost as they believe it is more accurate.

The wastegate works by opening when the desired boost has been reached, thereby preventing too much boost. There are a number of ways you can control this:

A) fitting a bleed valve - this deceives the wastegate actuator by into thinking that it hasn't developed enough boost to open the gate until it it is at a higher boost than the actuator was designed for - you have to manually dial in the boost you want.

B) EBC - much more accurate than the bleed valve and will automatically take into account atmospheric conditions to give you accurate boost at whatever pressure you set - these will bring on boost alot quicker than a bleed valve and also dont have as many problems with boost spikes. Whilst more expensive this is probably one of the best ways to control boost - cost notwithstanding.

C) Upgraded wastegate actuator - HKS have release a range of upgraded wastegate acturators that utilise a higher minimum boost threshold before they open - they will hold the wastegate shut longer - eg minimum boost required, in one example, is I believe 9psi. Probably better than a bleed valve, as it is less prone to spike, but not adjustable, also less likely to creep.

This is a pretty basic reply - if I have got anything wrong, please someone, correct me.

Steve

[predator]

Some good info there Steve! Thanx!

[raist60]

Steve an undersized wastegate will cause overboost... a 45mm gate will be fine for your turbs.

[GTS-t VSPEC]

Steve,

I'm pretty sure that if the wastegate is undersized that when the wastegate opens it doesn't release the pressure fast enough and casues back-pressure build-up and will play havock with getting on boost again. I'm confident that 45mm will be fine for a 3037s, if you were using a huge turbo then scale the wastegate accordingly.

See'ya:burnout:

[Steve]

Thanks for the replies and predator666 - you're welcome.

The reason I was thinking about undersize is I can get a HKS standard 40mm wastegate for $290, and its in really nice condition

Think I'll give it a try and see what happens - just have to do it carefully so I dont blow anything up..hehehe. If it is no good I'll just sell him and get a bigger one.

Thanks again

Steve

[GTS-t VSPEC]

The 40mm should probably still do it, you'll find out on the dyno whether it is working well enough. Sounds like you car is starting to make serious progress Steve, pity you had to move to Adeliade to do it.

See'ya:burnout:

[Steve]

Well my credit card bill is making serious progress - wont be able to get the turbo up and running until end of march when I have some more funds for the manifold and injectors/fuel pump. Tilbrooks tell me that they can fit top feeds in with the stock plenum - which is not going to be there forever just until I get the heads done. But this will save me needing to get all the money at once and if I'm lucky a second hand plenum might become available - Yeh right.

Till then, all I can do is dream

Would have like to stay in Perth, but sometimes you don't have too much of a choice - People here are really friendly (was quite taken aback when I got here), dare I say it, friendlier than in Perth - but the roads - Perth is heaven compared to Adelaide city - just glad I have got Ohlins suspension instead of some kidney jarring setup.

All in all anywhere in austalia isn't too shabby.