gt2860rs .64 rear housing overboost gen3 3s-gte, Fixed overboost (atleast so far) Options

[delusionz]

Any suggestions? I want to run 16psi, the included actuator should be 12psi but its spiking to 20psi alot faster than i can let off the throttle

am going to pull the downpipe off and test the actuator with a pump, maybe change from 5mm hose to 8mm hose? (Mr Garry's actuator nipple seems a little bigger than Mr CT's)

but has anyone seen this themselves and seen an effective fix short of going external?

if my actuator and door are operating as normal, will porting the gate do the trick? any special tricks?

This post has been edited by delusionz: May 24, 2011 - 12:18 AM

[Culpable04]

make sure to check the downpipe, sometimes the wastegate is not opening completely because it hits the downpipe, so once taken apart the wastegate would operate normally.

and what kind of boost controller are you using ? if it's an electronic boost controller, you will have to set the gain for the new turbo, I know on a Blitz dual SBC the recommended gain setting for a CT based turbo is 5, but that would be different once you go aftermarket.

[delusionz]

started with my HKS EVC I hooked up, then tried bypassing it alltogether, still the same

[Rusty]

Is it an adjustable actuator? Try winding it out a bit. Had the same sort of problem on my brothers old gt starlet(ct9 with HKS adjustable actuator).

[presure2]

creep is pretty common with the internal gated 'rs on the 3s...i assume your running a 3" free flowing exhaust?
some guys have installed a restrictor into the exhaust, others have welded the internal gate shut and go external gate.
IIRC jgreening had problems with creep with his setup, and went with a 11psi actuator that would creep to ~14 or somthing like that.

[korban]

Although i'm going to an external wastegate, i've been advised to run 5psi spring pressure, and let the boost control take it up to 16psi+.

[delusionz]

Fixed overboost.

The wastegate hole was bored out an extra 3mm and the path on the inside was grinded out to direct more flow towards the wastegate instead of straight down to the turbine.

Also the swivelling bracket was modified to bring the actuator arm closer to the pivot point so that the door opens wider. The standard actuator arm only moves so far, in effect the wastegate door opens about 45 degrees instead of 90 deg

Now it seems to hang on to 0.9bar instead of shooting upwards of 1.4bar. I've lost alot of low end response and some midrange punch but I think this can be remedied with a better EBC.

I haven't revved out to 7000 yet, So I'll update this later.

If problems persist, the next step will be fitting either a 2.25" or 2.5" restrictor before the rear muffler

[delusionz]

I dialed my HKS EVC to the 1.0bar marker and hopped onto a motorway onramp, successfully hitting 7000 rpm through 1st and 2nd gears with the boost needle snap to 1.0bar @ 3000 and held there until redline, this thing has assload more power than ct26/t04e-46 hybrid had on 1.15bar and extra 1500rpm early spool

[delusionz]

I only managed to push 5500rpm in 3rd gear otherwise going excessive speed but so far so good.

I was hitting 1.4bar around 4000ish in all gears before with the turbo housing ungrinded.

So now I get to keep my exhaust diameter at 3" through the entire system

This post has been edited by delusionz: May 24, 2011 - 11:02 AM

[presure2]

excellent!!!
do you have any pics of the porting work?
the disco potato is hard to beat for response time and overall streetability!

[delusionz]

Nope.. done it again. I had a good trashing today, just once somewhere at the top of 3rd I don't know where I wasn't looking down but out of the corner of my eye I saw the boost gauge creep towards 1.2bars as fuel cut occured.

1.2 bar = 17.4045285 pounds per square inch

So it's nothing like before where at anywhere between 4000rpm - 6000rpm from 2nd gear onwards the gauge would snap to 1.4bars before abruptly cutting fuel.

This just happened once, so 2nd gear is holding to my boost setting of 1bar, but somewhere near the end of 3rd its still wandering off (depending on conditions) which means 4th gear will do it earlier (not that 4th gear matters, speed cut will set in around the same time as boost cut anyways)

----

So if I want to continue on the stock ecu I have 2 options. A. ruin my nice merge collector on my T28 manifold with an external WG port, or B what size exhaust restrictor should I use and where should I place it? At the moment I have a 3" straight through free flowing system, no cats or mufflers, a 3" pipe squashes down to the EXACT same size as the T28 exit flange so theres no extra bits welded on as there was with the ct20b downpipe.