Yeah, I said it...

Here's the deal - #10 & 3KGSK were installed. The #10 is just about full forward.

Under WOT, I can get 37-40psi.

I have an adjustable fitting in the wastegate line, but opening it up made it drop from a consistant 40, to about 37... I want to get down to the low-mid 30's... Is the wastegate just maxed out?

I'm thinking putting the stock elbow back in wouldn't be a good thing..

 

had that problem initially also, ended up changing up to a bigger fitting bleed off valve (1/4") as the smaller bleed wasn't letting enough air escape. I also "slugged" the line on the turbo side with an allen plug, which I drilled a 1/16" orifice in. Still can't get it down below 30 (not that I want to). Because the stock turbo only wastegates 3 cylinders, the other 3 are still supplying enough energy to run the turbo up. You can ventilate the turbine housing to allow all 6 to wastegate, but not sure how this is done. I have read several posts regarding it though. Next step is bigger charger??

ATS is about to unvail a variable geometery turbo for the 12 valvers that requires no electronics. They have been R&D'ing it for 2 years and are debut-ing it in a month or two. They also have the Aurora 5000. Supposed nasty nine low end, and 75 psi top end with a 1:1 pressure ratio. I'm going to wait and see how the smoke settles....so to speak

Chris

 

On my '95 I had my plate grinded (#6) 3gsk, 370's, and 181dv's. Mine would boost up to 50 psi. I usually tried to keep it around 45 psi. It had 230k on it and no problems.

 

If you go to Holsets website, they offer a pneumatic variable Geometry turbo in the E series. This technology already exists from the manufacturer.

As far as boost is concerned, a change in turbo exhaust housings would help a bit. Dropping down to a 16cm non-gated housing would afford more flow and slow the turbo down a bit. Generally more boost is good, more air brings cooler EGT, but in this case the 12Cm housing is causing alot of backpressure on the engine at those boost levels. This is just making heat. Also the Hx doesn't live long at those levels.

I would try a 16 housing or go to another turbo.

J-eh

 

Nasty nine low end and 75psi top end

 

Wot's wrong with 37-40psi at WOT?

 

Nothing wrong with 37-40 psi on your turbo.

But it's over reving a stock turbo. Pumping super heated (less dense) air, loosing HP, increasing back pressure (TIP) and, in general, operating way outside efficiency "map" for turbo. In past...some have actually blown apart pushing 50 psi...you DON'T want to be there if that happens at over 100,000 rpm.

RJ

 

my hx 35 has been pushing 40 psi or so for over 50k miles, i have had it as high as 53 with the 12cm exhaust housing. i have a wategated 14cm on it now with my own spring hold down set up. i don't worry about a hx till it is over 40 psi. o yea this is the factory original, with only 257k on it.

 

That's what I said....it can't possibly work. He said wait and see. Only problem is the whole turbo end to end is proprietary and in house designed and manufactured. That means longevity in parts availability issues. Don't know the cost either. But I was told by another who has seen this turbo in action that on the truck it was on, it made 1 lb of boost in gear at idle, and indeed ran up to 60 psi fast. I would like to know some IAT and drive pressures though. This is the whole reason I have waited to enter the turbo race.....compounds are common now, mechanical variable geometry units are available, what's next?? I need to makew a decision fast though because my little 35 is getting tired of working hard.

Chris

 

The Banks VG turbo in the Xtreme 4x4 show last weekend (second half this weekend) was an electronically connected turbo. I interpreted that to mean it was controlled electronically, and I believe Mr Banks described it as parameters gathered and processed in the computer are then used to control the position of the wheel in the compressor housing.

 

Economy is better with the lower boost pressures. EGT's are cooler with the higher pressures. At least that is what I have been able to gain from reading everything I can get on the subject. I plan on going to a 16 or even an 18 on mine. but I am always wot pulling hills with very low EGT's. Mine hits the waste gate at very low throttle opening. Except for flat easy pulling mine is always on 30 with the gate open.

 

Before you buy another housing, you can try drilling the center divider on your 12 cm. That got my boost under control.
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