External Wastegate Advantages ?

2702 Views 18 Replies 11 Participants Last post by rub-a-vee-dub, Feb 15, 2002

Speed-Freak

Discussion Starter · Feb 12, 2002

If this has been asked and beaten to death before please tell me. I searched and did not find anything though.
What is the advantage to running an external wastegate versus an internal wastegate ?
SF

1 - 19 of 19 Posts

VWTornado

· #2 · Feb 12, 2002

Re: External Wastegate Advantages ? (Speed-Freak)

Internal can only handle around 300 crank HP. External is capable of WAY more. Thats all i know..sorry.

Boostcreep

· #3 · Feb 12, 2002

Re: External Wastegate Advantages ? (VWTornado)

It's a more precise way of controlling boost as well.

Speed-Freak

Discussion Starter · #4 · Feb 12, 2002

Re: External Wastegate Advantages ? (VWTornado)

quote:[HR][/HR]Internal can only handle around 300 crank HP. External is capable of WAY more. Thats all i know..sorry.[HR][/HR]

That can't be correct. Why would a "Super 60" that can do 400+ be offered with an internal wastegate?
SF

GerManRacer

· #5 · Feb 12, 2002

Re: External Wastegate Advantages ? (Speed-Freak)

I don't think a super 60 is going to do 400hp+! Billy had a t3s70 that couldn't break into 400's, he only got ~390hp

only, hehehe...

[Modified by GerManRacer, 8:30 PM 2-12-2002]

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2

mrkrad

· #6 · Feb 12, 2002

Re: External Wastegate Advantages ? (GerManRacer)

super 60's are good for about 300hp without blowing too much heat. The problem is once your exhaust flows better than the wastegate, the natural direction of gases will choose the exhaust...
boost creep will occur because the flow of gases doesn't want to exit the wastegate and you'll have uncontrollable boost.

Bug_Power

· #7 · Feb 12, 2002

Re: External Wastegate Advantages ? (mrkrad)

Yeah with externals typically your area for exhaust gasses to be expelled is MUCH bigger thus making boost overruns or boost creap a thing of the past.

Speed-Freak

Discussion Starter · #8 · Feb 13, 2002

Re: External Wastegate Advantages ? (Bug_Power)

So, if I am wanting to hit 350 pr 400 crank Hp, I would not be able to use a Super 60 ?
I will assume that the PES kit that uses a GT28 could do 350 crank Hp. Would a GT25 do 350 crank Hp ?
All turbos being internal wastegate.
SF

Bug_Power

· #9 · Feb 13, 2002

Re: External Wastegate Advantages ? (Speed-Freak)

yes you can get 350 from a gt25 on race gas

AZGolf

· #10 · Feb 13, 2002

Re: External Wastegate Advantages ? (Speed-Freak)

quote:[HR][/HR]So, if I am wanting to hit 350 pr 400 crank Hp, I would not be able to use a Super 60 ?
I will assume that the PES kit that uses a GT28 could do 350 crank Hp. Would a GT25 do 350 crank Hp ?
All turbos being internal wastegate.
SF
[HR][/HR]

Maybe you can, but again, you may have problems with poor boost control. There's a shop here in Phoenix which has done probably 8 GT25 upgrades on Porsche 944's and they always use a Tial external wastegate. Most of those cars make around 400whp on high boost. I think it's mainly a matter of reliability, not just "can it be done".

Speed-Freak

Discussion Starter · #11 · Feb 14, 2002

Re: External Wastegate Advantages ? (AZGolf)

Thanks AZGolf.
Would going to an external wategate help with spooling ?
(I imagine it would, being less restrictive/turbulant exhaust)
SF

16vracer

· #12 · Feb 14, 2002

Re: External Wastegate Advantages ? (Speed-Freak)

Can someone explain something to me? What exactly does a wastegate do? Why is there waste?
If there is a DV or BOV, then what is the wastegate for?

Please enlighten me. I know we have internal WGs stock...but what for?

HK_PREDATOR

· #13 · Feb 14, 2002

Re: External Wastegate Advantages ? (16vracer)

They keep your turbo from grenading basically. When the appropriate boost level is reached and/or gets exceeded the wastegate opens and dumps the exhaust gas into the DP.

16vracer

· #14 · Feb 14, 2002

Re: External Wastegate Advantages ? (HK_PREDATOR)

quote:[HR][/HR]They keep your turbo from grenading basically. When the appropriate boost level is reached and/or gets exceeded the wastegate opens and dumps the exhaust gas into the DP.[HR][/HR]

But how does it know the appropriate boost level?
I saw in Bug_Power's post that he ordered a 8psi spring Tial 35mm Ext. WG, so 8PSI....but the boost will be 15-22psi, so shouldn't the WG be 22psi?
I'm just trying to understand. Further, is ATP's software engineered for an 8psi- spring WG, or are we just "testing" ?
Does the WG require any adjustments, or just bolt on with the stg3 kit and it's ready to go?

Speed-Freak

Discussion Starter · #15 · Feb 14, 2002

Re: External Wastegate Advantages ? (16vracer)

The wategate is a device that is basically a valve that opens to allow exhaust gasses to bypass the turbo compressor. This then keeps the turbo from continuing to accelerate.
An internal wastegate is cast into the exhaust side of the turbo and is a small valve that opens. An external wastegate mounts on the exhaust manifold and allows exhaust gasses to bypass the turbo all together. (See ATP T3/T4 manifold for example)
The wastegate uses a hose to get preussere readings just live out DV's and BOV's.
SF

16vracer

· #16 · Feb 14, 2002

Re: External Wastegate Advantages ? (Speed-Freak)

Speed-Freak- that helped alot. I now understand. Thanks http://****************.com/smile/emthup.gif

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Speed-Freak

Discussion Starter · #17 · Feb 15, 2002

Re: External Wastegate Advantages ? (16vracer)

Yeah, so anyway........
Would an external wastegate help the turbo to spool faster ?
SF

TurbingNYC

· #18 · Feb 15, 2002

Re: External Wastegate Advantages ? (Speed-Freak)

ok ok....wastegate is not to be measured by a HP means, but by rather PSI or exhaust volume....internal wastegate isgood for small turbos and low psi(ex.up to 18psi or no greater than t3/03 in most cases) external wastegate anything above that should work excellent....now hee's why....as you all know the internalhas a small opening that's why at high RPM and big turbos the little opening can create big mess in controlling the boost and letting all these gasses out into the muffla...let's just say it will create drag in the exhaust system...now people gone with bigger internal ones but how big can you go in the exhaust side of the turbo??? not big...that why an external unit was made.. which help to keep steady boost at high PSI and RPMs....due to the much larger piston area than the little exhaust door.,...

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rub-a-vee-dub

· #19 · Feb 15, 2002

Re: External Wastegate Advantages ? (TurbingNYC)

i've never seen a compressor map for a super 70, but just for info., when compared, a T3/T4 50 vs. a T3/T4 54 vs. a T3/T4 60 trim, the 50 looked the best.

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