Hi all, new to this forum, looking for some advice as i'm really stuck now.
I recently fitted a td05 unit to my 2.0 starion.
First off, i fitted it with the standard actuator and used it in conjunction with a MBC.
Without the MBC, i was hitting like 7psi, not really any spiking, just not enough boost. So using the MBC set to approx 14/15psi, i noticed it spiking well above that, eventually settling back down.

So i bought a brand new turbosmart MBC thinking that was my issue, however it made no difference.

I then purchased a 1.0bar actuator thinking this would solve it. However it still spikes like hell, it seems to spike worse in lower gears, almost the opposite to boost creep.

I moved the actuator vac hose from the crossover pipe, shortened it right down so it is taking a reference from the turbo outlet pipe, again no difference.

What else can i do? Could my downpipe be my issue?

thanks for any help

Seb

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Definitely seems like you have a delay in your wastegate control system.
Perhaps your control lines (or fittings) are too small in diameter or too long or you have a large volume that needs to fill before the muscle unit starts to move.

 

I also tried a larger bore vac hose, did not make any difference and i moved the ref point from the crossover pipe to the turbo outlet pipe, it's now very short, only just long enough to reach between actuator and turbo outlet.
Do you think an electronic boost controller could stop the boost spike?

 

Is it spiking with the actuator connected directly to a boost source?

MBCs with the check ball are well-known for the tendency to cause a spike above the boost set point. It's just how they work. I prefer a bleed-type like OEMs have used. Bleeders also keep the wastegate diaphragm from being overpressured if the boost is set above the actuator's physical limit.

 

with the 1.0bar upgraded actuator it spikes, that's with it directly connected from turbo outlet to actuator.
With the standard actuator it only boosts to something like 8 psi, but it does not appear to spike, that's with it directly connected. Maybe it's not letting enough boost be produced to let it spike. With a brand new turbosmart MBC fitted, it spikes when connected in line with the standard actuator.
Both standard and upgraded actuators i set up with 2mm preload.
I'm considering an electronic boost controller, but i don't know how quickly they react? if that could prevent the spike and keep boost steady

 

Have you tried porting the internal wastegate to better bleed off exhaust pressure?

 

The 8psi actuator working properly suggests that the wastegate size is not an issue.

Do you have any way to datalog what's happening?

 

I did port it a little before i fitted the turbo. In higher gears i can get my foot flat to the floor and the boost actually drops as opposed to creeping up

 

Ok, unfortunately i don't, it's the standard ecu fitted

 

What vacuum/boost hose are you using?

I've heard of thin-walled/rubber hose can cause issues but haven't seen it myself.

If you are using a manual boost controller have you considered just changing the wastegate spring to suit your needs?

The reason I say this is if it works why change it?

 

I've not looked at the car for a while over the winter, but i believe it was some 4mm silicone hose i was using

i tried an uprated actuator fitted with a 1.0 bar spring, but again, this was still causing a boost spike

I have an EBC to go on the car when i get a bit of time to see if that can control the boost a bit better

 

Just for info to help someone out in the future.....i fitted a HKS EVC electronic boost controller, this has solved my boost spike issue

 

Wish I would have read your thread 2years before I joined the forum. Some info to add to this thread:

The problem was the turbosmart style manual boost controller, they have a ball and spring in them that holds off boost signal to the wastegate until it reaches it set point, by then it's too late the boost spikes as the wastegate opens, then boost settles. The spikes are much worse when spooling in 4th or 5th on the highway.
Ran these types of boost controllers in the early 2000's, constantly pulling over to open the hood and adjust boost. Have to turn it up at the drag track, turn it down on the highway and on cold nights... These types of boost controllers spike less at the drag track if your on the gas and maintain boost the whole run but suck on the road or race tracks, every time your off throttle and floor it again the boost spikes.
Also the tiny spring tends to loose tension with heat so set boost drops the harder the cars is driven.

The best manual boost control set-up uses a simple adjustable valve, the more you open it the more air passes through it.


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You simply bleed off the extra boost you want over the wastegate pressure.
So if the wastegate is rated at 7psi and the bleed off manual valve is set to 5psi, air will choose the path of least resistance, the first 5psi of boost bleed through the manual valve, at 10 psi of boost 5psi is on the wastegate actuator, at 12psi boost the wastegate operates like it would at 7psi without a boost controller, even if boost is instant. The inline reducer simply amplifies the the sensitivity of the manual boost controller, the smaller the reducer is the less the boost controller needs to be turned to increase boost.
The only thing that changes is the increased exhaust pressure against the waste gate flap and that's why the hole should be ported.
I have been running this boost control set up on all my cars for almost 20years, I have never had to adjust set boost on the hottest summer day or the coldest winter night, this controller set-up holds steady boost from spool to rpm cut, never has spikes or drops and that's the irony, this boost control set up is in dash at the drivers finger tips but never needs to be adjusted. Ball and spring manual boost controllers sit under the hood but need constant adjusting.

So to anyone with a budget build or who just doesn't like adding more electronics to their cars don't buy a turbosmart style ball and spring boost controller.
A ball valve, a sink tap knob or drilling tiny holes in the waste gate hose until desired boost is achieved is better boost control than these ball and spring boost controllers.

 

If you go to atmosphere without a check valve you'll pull unfiltered air that will effect idle settings even on speed density systems.

 

That is true but also why I mention running it back to inlet air. However the inline reducer hole is between 0.04" and 0.070" ID and seems to have no effect on idle or air fuel ratios when dumped to atmosphere on most metered air systems.

Tial wastegates installation instructions are to vent bleed off air to atmosphere, don't call for a check valve or inline reducer and don't have any idle or air fuel ratio effects on most cars.

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I could see running a manual controller close to the boost signal source and letting air vent out the outlet port causing idle and driving air fuel issues.

I would say the fact air chooses the pat of least resistance, running hose from the engine bay to the dash, through the controller and back into the engine bay reduces the amount of air sucked in by engine vacuum.
But the inline reducer before the wastegate and boost controller T is what really limits the amount of air that can be drawn back through the manual boost control valve, if the reducer has an I.D. of 0.050" the manual boost controller would only need a 0.035" id passage (based on area) to bleed off half the air going to the waste gate and double boost output.

 

That is true but also why I mention running it back to inlet air. However the inline reducer hole is between 0.04" and 0.070" ID and seems to have no effect on idle or air fuel ratios when dumped to atmosphere on most metered air systems.

Tial wastegates installation instructions are to vent bleed off air to atmosphere, don't call for a check valve or inline reducer and don't have any idle or air fuel ratio effects on most cars.

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I could see running a manual controller close to the boost signal source and letting air vent out the outlet port causing idle and driving air fuel issues.

I would say the fact air chooses the pat of least resistance, running hose from the engine bay to the dash, through the controller and back into the engine bay reduces the amount of air sucked in by engine vacuum.
But the inline reducer before the wastegate and boost controller T is what really limits the amount of air that can be drawn back through the manual boost control valve, if the reducer has an I.D. of 0.050" the manual boost controller would only need a 0.035" id passage (based on area) to bleed off half the air going to the waste gate and double boost output.