Hiboost

iTrader: (9)

So from what I am gathering the stock actuator may be able to adjust minimum boost levels from 16 up to 18 PSI where as the Forge can bring that up to 21 PSI and beyond using the stiffer spring? This is assuming that the crackpressure where the actuator starts to move is about 2 PSI less than those numbers. I'm sure in a 100% stock setup where you are getting 16 PSI at redline, just swapping a Forge in can give you a solid boost increase that may well be 30-40 whp at the top end. However with a manual boost controller and the stock actuator adjusted in it may be very similar results based on the fact I am already getting 20 PSI with an MBC.

I'll see what I can find out tonight once I get my exhaust bolted on and boost set again. I'll adjust my arm in and see if I can increase my max boost near redline in 3rd gear.

benklepacki

So if you were using an EBC like the AVC-R you can pretty much tune around getting a new actuator?

benklepacki

double post, sorry

Geo@SpeedClinic

iTrader: (2)

We adjusted our stock one and it was not enough to run the boost we wanted to. The Forge works wonders just like it does for the older evos. Definately recommended.

Mike@Forge

iTrader: (23)

As I said earlier, the higher spring pressure within our unit allows for the wastegate flapper to be held closed tighter and for longer against the exhaust gas pressure flowing through the turbo.

With the weaker spring of the stock unit, as well as the poor placement of the wastegate flapper within the exhaust housing, the exhaust gas pressure can easily force the wastegate flapper open prematurely. When this occurs, the exhaust gas that is supposed to be spooling the turbo is dumped which will slow the speed of the compressor wheel and limit the potential to build boost further.

Tightening the stock unit will have the same effect as ours, as many people are finding, but to a much lower degree. You're working with an altogether weaker spring to begin with. Somewhere in the neighborhood of 12-15 PSI base pressure.

We assemble our units with a 19-24 PSI base spring pressure, so the possibility of the exhaust gas pressure prematurely opening the flapper against this higher spring pressure is minimized, if not completely eliminated.

All of the exhaust gas is kept within the exhaust housing of the turbo and is forced to continue spooling the wheels keeping boost at it's peak potential.

A boost controller will still allow you to adjust up from the base actuator spring pressure, and it will open the actuator when the target boost pressure is reached, but with the stock unit, there is still the potential for the exhaust gas pressure to prematurely open the wastegate BEFORE peak boost is reached and the boost controller would send the signal to open the actuator.

With our unit, the boost controller will still function in the same way, sending the pressure signal to the actuator to open it fully when the target boost level is reached, but there is far less chance of the exhaust gas pressure opening the flapper before that occurs.

Depending upon how the units are adjusted, you will see changes like quicker spool, less tapering, and an overall increase in the area under the boost curve. The units are piston based, and fully rebuildable. They carry a lifetime warranty.

teamturbo

The stock actuator simply will not hold increased boost pressure to redline. Add a flash with an extended rpm range this issue increasingly gets worse.

Boost Controller allows you to spike higher and indeed will increase the power because of that but undisputed fact remains the boost will still taper off.

We are holding a solid 30psi on our car everyday. The car is on forge actuator and a mbc.

Red Dragon

iTrader: (17)

is that with a tune? How much boost do you spike to?

Has anyone trigger limp mode while running 30psi to redline?

I would like to see some dynos on a stock evo x with wastegate actuator and boost controller.

Hiboost

iTrader: (9)

Thanks Mike, that makes sense then! Basically it's almost as strong/controllable as an external wastegate with just the upgraded internal WG actuator. I've got about a 3-4 PSI taper now on the stock turbo, I would imagine some of that is the small turbo running out of steam but the actuator tapering the boost due to being forced open by the exhaust flow is worth saving assuming my charge temps are ok with an upgraded FMIC.

Hiboost

iTrader: (9)

BTW I adjusted my actuator in 3 turns and got some interesting results.

Backed the MBC down 2 full turns since I figured it would start at 2 PSI higher than before.

Spike to 25 PSI, settled at 23 PSI in 5th gear so I think great!

Well as soon as the RPM's got past 4k it started to creep higher.

Next test as 4th gear and it Spiked to 25 PSI and, settled at 23 PSI but 4k+ it started to head past 26 PSI.

I have the boost restrictor pill in the boost lines right off the turbo source so either:

A) The source boost is too weak and getting out powered by the 3 turns in WG actuator

B) The maximum opening angle of the internal WG is now too restrictive and forcing exhaust flow at higher RPM's to spin the turbo faster.

C) Both things are happening!

The max turns on my car was 3 and 3.5 wouldn't flip into the proper angle to put on the WG actuator arm. Once it all cools down I'll try it with just 2 turns in and see what happens. If it still seems uncontrollable at higher RPM's I'll swap in a regular non boost pill restricted hose off the turbo boost source.

Maybe the bleed hole is too big in relation to the signal coming in. Looks like I'll be busy tonight!

Hiboost

iTrader: (9)

And the answer is:

B) The maximum opening angle of the internal WG is now too restrictive and forcing exhaust flow at higher RPM's to spin the turbo faster.

So with my mod level I am actually getting boost creep with 3 turns on the WG actuator rod!

I tested this with:

MBC adjusted to 15 PSI with very small bleed hole.
Boost hits 15 PSI, stays there til 4000 RPM in 4th then takes off towards 26 PSI as it approaches 5000 RPM when I of course let off.

Just in case I also tested with a hose from the Turbo directly to WG Actuator and I got identical behaviour... The angle of that internal WG flapper must really choke the flow off towards the end of the adjustment!

So basically I'm going to back the WG Actuator mod down to +2 turns and see where that gets me. As long as my minimum boost with the creep on the top end sticks around 23 PSI I'll be good with that and can use the MBC to tweak it slightly upwards from there. A quick tip on the exhaust heat shield, you can remove the 5 bolts and then shift it towards the passenger side and slide the left side downwards and out of the way. Beats trying to force it past the front strut bar and valve cover by miles.

Mike@Forge

iTrader: (23)

With our units, you maintain just as much, if not more travel within the flapper's range of motion than the stock actuator, so for every adjustment you make with our unit, you'll have the same level of travel as a similar level of adjustment of the stock unit.

STi2EvoX

The stock turbo will not hold 30 psi to redline, it'll just hit it for a couple hundred rpms and then fall on it's face. I don't understand why everyone wants to run such high boost on this baby stock turbo. It's more effective to just raise the turbo's boost to it's maximum efficiency and then just run timing to make power. Cylinder pressure is cylinder pressure, whether it comes from compression ratio, boost, or timing, so it's best to make power in a way that keeps everything efficient and cool. When you raise the boost far beyond what the turbo's really capable of doing, it overheats the turbo and just blows hot air, heat soaking the intercooler and pumping your engine full of hot air.

Plus, you overspin the turbo and it puts lots of stress on the bearings and it just plain wears the turbo out and causes premature failures. If you want to run 30 psi all the way to redline then get a GT3076, run some race gas and then call it a day. A turbo like that will actually be able to hold the boost to redline and still stay cool and efficient because it was designed to do so. Now just to be clear, I'm not saying that rasing the boost doesn't have a positive effect on the stock turbo but it has to be done within the turbo's efficiency range.

Robevo RS

iTrader: (16)

its funny how you call the X turbo "baby stock turbo"
when actually moves alots of air, due for the deign. FACT the new factory video stating about the new turbo:
it is a completely different , larger size and improve performance. Build for big boost pressure and moves a huge amount of air compare to the previous one's.
Around 5 minutes 10 second in the first cd/video/

i try to find the video on youtube, but i know is it somewhere in this forum too.

STi2EvoX

^Well, what you are failing to realize is that the compressor housing is actually smaller on the new turbo. It's a 15g housing compared to the 9's 16g housing. The compressor wheel itself is similar in size, and the hotside is bigger but it still limits the amount of lbs/min flow of the turbo when compared to last year's model. This is the reason why the taper characteristics of the new turbo are worse than the evo 9.

The X's engine has a lot of improvements and it's a better overall engine in my opinion, but the turbo is not better than the 9's. That training video is just spouting off corporate nonsene that's been put into the brochure to sound good. The real truth of the matter is that the new turbo has been optimized to produce more boost pressure than the 9's turbo at low rpms to help spool up characteristics but at the expense of high rpm output. This doesn't matter that much because the new engine is more efficient and utilizes a better head design that allows high rpm power output even as the boost drops.

This combined with the fact that the engine has a square bore and stroke makes it more rev friendly and contributes to the engine being more willing to run higher timing at high rpms without detonation which as mentioned earlier, produces good power at high rpms even as the boost drops. Ask any shop and they'll tell you that the turbo on the 9 is a better turbo for making big power. Don't take this as me bashing the X, hell I own one and love it. I'm just saying that you can't think that everything is better about the X just because it's an OVERALL improvement compared to the 9.

Red Dragon

iTrader: (17)

How much hp increase will we see with the forge wastegate, tune, and manual boost controller??