external wastegate fab done. PICS! comments?

Jim Fulmer said:
Here is my first from either late 02' or early 03' I started out venting it to atmosphere then changed it over to the divorced setup and dropped 250 degrees of EGT.....think it works better.
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Jim
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That looks about the same as mine, even the same external gate.


CIMG0589.jpg
 
Smokem said:
A question that should have been asked; What are the turbine housing sizes on both chargers?
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the h1c is pictured with a 16cm housing, but i've got a new 12cm housing for it. and the 3b is a 26cm housing. the way i look at it is, spool it fast down low with the h1c/12 and then when it gets to a certain pressure, set the gate to open and route most of the exhaust to the primary to light it. am i wrong in my thinking here?
 
Charles said:
Exact same spot..... but without having to force itself through the tiny turbine housing/wheel of the second stage charger...

With your line of reasoning, what's the point of a wastegate on any engine.... I mean, all it's doing is dumping exhaust gas right to the place it was going anyway.... the atmosphere.

Except for the fact that it doesn't have to do it through a turbine housing and impart energy into a turbine wheel that you don't want receiving any more energy.
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thank u sir. u know what i am going for here
 
we had the gate dumping out down by the ground as a test. (only 65lbs of boost) plumped it in to hot and now (100lbs of boost) with our S475/.90 T4over S595/1.15 T6. drivepressure stays at 1 to1 all the way.
 
This is exactly what I want to do! The idea being to run a very tight housing on the small secondary to get nice part throttle boost, power, and response, than when full boogy comes on pass the drive along to a large primary, larger than one would be able to drive normally without the extra exhaust hitting the big primary.

Cool deal man!
 
NickTF said:
This is exactly what I want to do! The idea being to run a very tight housing on the small secondary to get nice part throttle boost, power, and response, than when full boogy comes on pass the drive along to a large primary, larger than one would be able to drive normally without the extra exhaust hitting the big primary.

Cool deal man!
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CORRECTAMUNDO:Cheer:
 
As quoted from a turbocharging book i picked up...A wastegate is a simple form of a variable geometry turbine.
 
I'm running 66/12 over a 480. External gate merged at the rear or the T6 plate. I can get the 66 lit by 1700RPMs by 40psi the gate opens fully and feeds the 480, when shes lit, HOLD ON!
 
Datalogging is worth its weight in gold!!! ;)

Below is a datalog of one of my dragstrip passes with the setup as pictured previously so you can see how it works.

White = RPM (0-3600)
Grey = Throttle Posistion (0-100%)
Orange = Secondary wastegate PWM control (0-100%) (100% = Wastegate completely closed, 0% = Wastegate fully open)
Yellow = Primary wastegate PWM control (0-100%) (same as above)
Green = Total Boost (0-72psi)
Blue = Primary Boost (0-72psi)

The Red cursor is indicating a point midway through 4th gear.

I have the wastegate control setup for a max of 70psi total boost and 30psi of primary boost.

As you can see, the secondary wastegate starts to open at 26psi and goes to approx. 70% open by the time 65psi total boost is reached. The primary wastegate starts to open at approx 26psi of primary boost and only needs to open 5% to keep it at 30psi.

This setup goes from 6psi primary and 24psi total boost spooling at the line to 22psi primary and 70psi total boost at the shift from 1st to 2nd gear and in less than 1.5 sec.

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Yup this works well. Thats how Chris's twins were setup back in 2004 when he was running 11.76 in his 24v #2 only.
 
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