Silvia Club of NSW

Am i correct thinking that a wategate is simply a means of removing unwanted exhaust gases before the turbine? Like how a BOV removes the unwanted air before it has a chance to back through the turbo...

Do most turbos come with an internal wastegate? Can an external wastegate be used in conjuntion with a turbo with an internal wategate? Whats the benefit of an external wategate?

Im thinking of upgrading to the HKS GT2835... what information do you have regarding wastegates for this turbo?

most turbos do have an internal wastegate, and you can use an external one at the same time......

The wastgate is what's used to control boost. When the appropriate boost level is reached the actuator opens the wastegate to vent exhaust gas out, bypassing the turbine. If all the exhaust had to go through the turbine it would just keep producing more boost, and spinning faster until the turbo failed.

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The Engine Whisperer - fixer of things

I see... so what would be the situation if you used an external wastegate instead of the internal one that is built into the turbo?

If i went with the HKS 2835 on a SR20DET, what type/size/etc external wastegate should i be looking for?

dunno about the size, but you could definately do it.. You might be better just to re grind the internal one for more flow though. Unless you're running massive amounts of power you won't really need an external one... (unless of course your turbo doesn't have an internal one )

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The Engine Whisperer - fixer of things

What do you consider massive amounts of power?

Im going for a mild 250kw at the wheels (180sx btw)... easily obtainable without an external wastegate, but with of course the other right gear.

I would call 250 at the wheels massive for an SR20, considering it will need major internal work as well as a huge turbo / cooler / fuel system, custom intake manifold, throttle body, etc...

The wastegate then becomes a question of whether or not the turbo you use has one on it already...

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The Engine Whisperer - fixer of things

damn..

250kw@rw = mild

i thought my 160-170kw@rw was mild.
makes my aim look like a chomp hehehe

i've heard that bigger wastegate the louder the fluttering noise gets.
is that true..

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Officer ! I swear its all factory standard.

RHiSC, a 35mm w/gate will do the job well. 250kW@wheels will NOT require upgraded internals, etc. It can be done, but you will need bigger injectors, pump, etc. I would even suggest a/market management for this.

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Project M111
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Use only under adult supervision

maybe, but so far we haven't seen anyone get over 200 without internal work...

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The Engine Whisperer - fixer of things

only in Japan... maybe it's their climate and their fuel.. damn bastards! why can't we get 100+ octane from the pump!!

dont use anything smaller then 42mm.
dont forget, large turbos such as the HKS GT2835 will expell alot of gasses. with a smaller wastegate your going to restrict your turbo's performance.

a smaller wastegate won't restrict the turbo, it will just limit the amount of power you can make while still controlling the boost.
If the wastegate's too small you'll run too much boost at high revs - so you need a bigger one to "waste" more gas to keep the turbo running slower.

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The Engine Whisperer - fixer of things

If you are looking at running high boost, a metal head gasket is at least suggested. Again, this is just opinion from my own experiences and trips to Japan.

There HKS 2835 version with internal wastegate, with the correct flange for an SR20.

Although this is an s15 they are referring too there is an article in one of the HPI or Zoom or maybe hot4s mags one of my friends have that they get close to 250rwkw from the sr20 no internal mods. New computer, FMIC and so on i will try and find out exactly which mag and maybe scan in the pages? While they refer to s15 shouldnt be too much more required for s13/s14 i hope anyway?
Hope this helps
Pete

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To be old and wise you must first be young and stupid.
If we aren't supposed to eat animals why are they made of meat?

Don't believe everything you read in mags, I know of at least one S15 they simply made up the power figure for as the owner hadn't dynoed it. Also don't believe everything a dyno says, particularly when it's being published in a mag, they're so easy to fudge it's not funny.

That said, you could get to 250kw atw without internal work, just not for long. By that stage you would need pistons and head bolts, I'd be doing rods, and sleeves. The head gasket actually can take quite a bit but you'd likely be replacing it. To get it to work properly you'd also be running bigger cams, likely upgraded valvetrain gear, possibly lash killer etc.

With the external wastegate you start to need them as basically they are bigger and have finer control. An internal gate struggles to clear the air and makes a bit of a mess of the airflow in the exhaust. The other big advantage is that with the external gate you can hold it completely closed for longer as it clears the gasses so much quicker, this makes quite a significant difference to spool time, lag etc. You wouldn't use the two together as you couldn't control them properly though you can use an external gate with an internally gated turbo, you just weld the internal gate up (not perfect, but it works).

Contrary to what some believe getting 250kwatw out of an S13 SR is a lot harder people think. I'd recommend that you actually sit down and talk to some people who have done it, and I mean really talk to them not just a quick chat, and find out just what it takes. On paper it often seems pretty simple, I can assure you the reality is quite different.