Got my car to a dyno today for it's first initial tune. We're a bit stumped on how late the boost is building. Another issue we're having is controlling the boost pressure. We aimed to run 10psi, using a Turbosmart Actuator and 10psi spring combo, but little f#cker of a turbo just want's to keep boosting once it's on.

Why do I want to limit boost, we'll my built motor is still in boxes in the garage, till then low boost.

Kraken manifold, EFR6258 .64a/r, 3" straight pipe, engine stock.

Up top we had to limit the timing, the high boost was causing valve float.

We also wired the wastegate open, boost still crept up to 4psi, which is kinda interesting too.

 

Common causes:

Lazy= boost leak, wastegate not closed completely, boost leak, wastegate not closed completely, cam timing off, spark timing off, displacement deficiency, wastegate signal source wrong, boost leak, wastegate not closed.

Overboost= small a/r, small wastegate opening, wastegate not opening fully, boost controls interfering, other things (needs coffee).

 

Cheers man, looked into the wategate opening.

Here's what I've got so far, stroke length is 20mm (0.78") which I think is correct according to the EFR Technical docs. Without removing the turbo I can't confirm it's opening fully. That will be a later resort.

Moving on to check the other suggestions.

 

Likely it's binding. I had the same issue tuning EO2K's car. gotta re-align the actuator rod properly

 

We didn't hookup EBS yet, so that might explain the laziness ???

Checked for binding, it moves really freely, we did built a custom bracket for the actuator, but it moves very easily. One thing I did noticed is.
Stock actuator throw ~20mm (0.78") total wastegate arm movement ~28 (1.1")
Turbosmart actuator throw ~15mm (0.59") total wastegate arm movement ~20mm (0.78")

So the stock actuator opens the gate way way further, so that might explain the overboost, the picture shows how far the stock actuator moved the gate, you can lightly make out my pen marks from the Turbosmart actuator

That's really concerning, anyone else using one of these actuators?

 

Which actuator is it?

I'm running a 7psi spring in a dual-port TurboSmart IWG75 on my 6758 0.85 A/R vBand setup, with a Gleaseman / Fab9 manifold and 3" downpipe and back. Obviously we aren't running equal things here, but I digress... If I leave my EBC disabled, boost onset is markedly slower but the turbo still caps out at 7psi quite reliably, actually tapering down just slightly beyond ~6750 into redline. With the EBC enabled and dialed in, it will load up 4th gear enough on a simple dynojet 248c roller to hit 15psi by 3650 and hold it flat to redilne; spool is easily 300RPM sooner on an actual road.

 

@albuquerquefx It's the Turbosmart IWG75 Single port actuator

 

I made a video showing the difference in how far the difference actuator opens the wastegate

 

The lack of opening angle certainly explains the overboost / creep, but doesn't explain "lazy." My first whack at fixing the opening angle, would be backing out the preload. I see you have some thread left, I'd see if backing it out to nearly the full extent fixes much. IIRC, my dual-port IWG75 wanted 3mm of preload, no less and no more, but it absolutely opens as much as the stock canister. If you disconnect both the stocker and the IWG, and hold them in free air, do both have the same actuator rod travel from unpressurized to fully pressurized? If so, then I'm suspect of your custom-made mounting flange. If not, I wonder if somehow you got a bad part...

On the "lazy" side of things, does the WG close fully / tightly when there is no pressure applied to the actuator can?

 

Stock Canister and Turbosmart one doesn't extend to equal lengths. Took them off and tested it side by side... I also tried with the stock mounting bracket didn't make any difference :(

This might sound extreme, but we're actually thinking of putting an external gate on it now

 

Use a stock one.

 

Yeah, this is where my head would start. First and foremost, it sounds like your IWG75 is somehow wrong or broken. If it cannot fully actuate the gate, then ****'s broke.

Second, why buy the IWG75 and only use a single port? The ONLY reason I replaced the BW can was to get that sweet sweet dual-port action (fapfapfap.)