[OZ200TT]

Hi Guys,

Is it possible to fit an external wastegate on the stock twin turbo setup? If so, what modifications would I have to do? Extractors with a dump pipe?
HAve any of you guys done this? If so, could you email me the pictures of it, and let me know what you've done. This would really help me out, thanks

 

[FYRARMS]

Uhhhhhh...

Well, anything is possible. But why? You would have to:
a) remove factory internal wastegates.
b) remove factory actuator assemblies.
c) weld shut the actuator rod holes left.
d) cut out hole in stock iron manifold.
e) weld on a wastegate flange to manifold.
f) run dump tube from wastegate to exhaust, or leave open.
g) accept laughter from other MKIV owners.

External wastegates are only needed when boost control becomes uncontrollable. With a properly installed electronic boost controller, you will not have any boost creep issues.

Furthermore, use internal wastegates when possible. External units create excess underhood heat, are sometimes problematic for fitment/clearance issues, and are expensive.

My old employer, Hahn Racecraft, may be installing twin INTERNAL wastegate TD06-20G-10CM2 turbos on a custom header for me. Should be good for over 800rwhp and NO boost creep. Half the price of the ridiculously-priced HKS twin setup.

 

[agm]

this is about the only thread i can find thats relevant to a malfunctional stock internal wastegate

my wastegate has a mind of its own since a few days ago on the highway.
i can hear air randomly rushing through the exhaust and my blow off valve isnt making any noise.
if i let off the throttle when its doing that and hammer down quickly after it will shut the wastegate and the car will boost normally (and you can feel the power increase significantly)
then the car will randomly perform perfect for a few seconds or an hour (you never know)

as far as i understand you cant buy just the oem actuator. (aftermarket may be possible, ill check in about an hour with dave.)

TLDR:
if its not possible to replace oem actuator, should i convert to external or just put the car asleep til next spring and upgrade turbos.
thx

discuss.

 

[Nick 95 6sp]

it's complicated, so IMO only somebody who simply wants to do it "because I can" would do this...but here's a bunch of pics and details on what's involved: http://www.utahracing.com/supras/matt/matt94/wastegate/index.htm

 

[Nick 95 6sp]

this is about the only thread i can find thats relevant to a malfunctional stock internal wastegate

my wastegate has a mind of its own since a few days ago on the highway.
i can hear air randomly rushing through the exhaust and my blow off valve isnt making any noise.
if i let off the throttle when its doing that and hammer down quickly after it will shut the wastegate and the car will boost normally (and you can feel the power increase significantly)
then the car will randomly perform perfect for a few seconds or an hour (you never know)

as far as i understand you cant buy just the oem actuator. (aftermarket may be possible, ill check in about an hour with dave.)

TLDR:
if its not possible to replace oem actuator, should i convert to external or just put the car asleep til next spring and upgrade turbos.
thx

discuss.

just curious if you're sure it's the wastegate and not your BOV? Otherwise, have you read Stu's troubleshooting guide for stock twins, which I'm pretty sure includes wastegate VSV testing? http://www.97supraturbo.com/FAQ.html

 

[agm]

actually i should check the vsv's

i dont think its my BOV though because i took it off and cleaned it out, so the piston moves perfectly and the spring is solid, aswell the hole leading into the top of the bov is unhindered (blitz supersound)

among other things i also did a boost leak test, where i found 2. now my car pulls a bit harder and runs perfect once again.... until it gets hot... that is to say it did.

now instead of hesitating a bit (which seems to be wastegate related as far as i can deduce+induce); the wastegate is just pretty much 100% open all the time.

but it will close if i let off the throttle and instantly get back on it, where it pulls normal up to redline, then when i switch gears the wastegate opens and stays open.


i will investigate the VSV's so thx for that. (is it possible for a vsv to malfunction with the symptoms im describing though?)

and i can tell you this is occuring in both sequential and ttc mode.