High boost on internal wastegate?

[Hypnotik]

I have a Forced Performance TD06 20g on my car with a HKS actuator and a Blitz Dual SBC Spec-R boost controller. My problem is that I cannot get it to HOLD more than 1.1bar. It will spike to 1.3-1.4bar then fall back to 1.1. I thought maybe the internal wastegate wasn't big enough but is seems that it should overboost instead of doing the opposite. I talked to another guy with the same turbo and he has the same problem.

I remember seeing this same turbo on a SR in a R32 skyline and they were making 458whp at around 1.7 bar so I know this turbo is capable but I can't seem to figure it out. Forced Performance advertised this turbo as capable of 29psi.

What is the highest boost some of you guys have been able to run on a internally wastegated SR?

[Def]

Add a secondary spring to the WG arm. Sounds like the turbine is inefficient (probably true for that turbo on an SR), so you're dealing with a ton of backpressure blowing open the WG port.

Bump up the spring pressure by adding a second linear spring and you should be fine. You can't do it just tensioning the WG arm (within reason, otherwise you'll just run out of travel and it won't control boost for crap high or low).

[Hypnotik]

Where would I put the spring? Open up the wastegate actuator somehow?

[Tower240sx]

take the boost controller out of the circuit and use the adjustable waste gate to achieve about 1/3 to 1/2 the max boost you want to run, a boost controller can really only effectively increase the holding ability of the W/G 2-3X, less if you want it stable.

this is because the w/g piston to valve face relationship is so poor in an internal gate setup


EDIT: to answer your question I have run 20 psi stable on my 2871r on internal W/G with the w/g set at 14.7 and the rest from an old profec B

[Hypnotik]

The wastegate is set at 1 bar. I want it to hold at least 1.3.

[Matt93SE]

You need to buy my TiAL external wastegate...

[eazye2000]

Wastegate flapper is being forced open. I had a T2 internal gated 3076R with an S compressor and I ended up externally gating it to fix the issue.

My $.02

[Tower240sx]

if the gate is set at 1 bar and you can't hold 1.1 you need to revisit the boost controller setup.

1 bar on a internal is not a big deal, yes exhaust gases force open the flapper...that's the intention right? but they also work, have for years, (decades actually)

An external on a application of this magnitude is not required (esp at this pressure ratio)

[Def]

Where would I put the spring? Open up the wastegate actuator somehow?

You want to keep the wastegate CLOSED. Add the spring so it's pulling back on the WG shaft.

I also have a Forge internal wastegate actuator that's missing a few bolts that's got a plenty stiff enough spring for you, plus you can change out the internal spring. If you're interested PM me.

[Black R]

You need to buy my TiAL external wastegate...


You the allmotor king have a wastegate fs?

Pm me a price if it's 40mm or bigger.

[Matt93SE]

You the allmotor king have a wastegate fs?

Pm me a price if it's 40mm or bigger.
I bought it about 8-9 years ago when I was planning a turbo build on my Maxima. then I got smart and quit trying to make a Maxima fast. :)

I don't remember the size of it, but it should be plenty for an S-chassis setup.
I'll have to look and see what it is and get back to you.

[CodyAce]

Internal gates suck. Plain and simple.

This fixes any boost issues:
http://www.codyace.com/albums/album20/manifolds_01.sized.jpg

http://www.codyace.com/albums/album20/manifolds_06.sized.jpg

:D



Truthfully though, the only way you can remotely fix big creep are by going with a aftermarket actuator (which I had no luck with), or putting on the springs (like Def suggested) or preloading the crap out the wastegate (which makes them fail).

Another option you can maybe try is setting the gain or onset on the controller to max, to see if it works for you to help hold off the gate from opening...I know on the profecs setting gain to 90 or so percent helped, but it made boost rush on and blow the tires off too.