Changing The Wastegate Actuator

[Plugg3r]

I ordered a 11.8psi actuator with new arm and bracket for my .70A/R housing.

But when trying to fit today the actuator wont fit as it touches the turbo and wont fit, you think they sent me a .50A/R bracket?

[HI PSI]

Turbo out.. You can do the majority yourself.. Machining of sealing suface is desireable...It depends on your fussy you are. My self ported housing is going on this weekend.. I found it alot easie by purchasing a spare housing and doing it at my own pace...

Check out this thread..

Bigger Flapper Thread

There is a simialr link in post 27 that shows some pics after porting and machining has been performed..s of the porting that I did..

Edited 25/02/10 08:34 PM by HI PSI

[conrad]

the porting of the exhaust housing is a must if you really would like to control the overboosting XR. Even though there are other forms of adjustment (ECU Tuning) sooner or later you are going to need this mod done once the boost is raised higher than factory.

Cheers

Conrad Lovett

[riptide]

If I understand this correctly the rating of the actuator is the minimum psi it can command. So if I had a 12psi actuator I could only control boost above 12psi? say 12psi to 25psi if it holds that much. At present I am running about 13psi max boost so I guess that only gives me a command range of 1psi with my 12psi actuator. Does this mean I would be better off with and 8psi or 10psi actuator to increase my command-able range to 3psi or 5psi below my maximum tuned boost and give me more acceleration control?

[Wenier]

The spring pressure on the wastegate is basically the lowest boost you can ever have. So 12psi gate you cant go below 12, so if your thinking bout having less than 12 at anytime (maybe a diff tune) then the 10psi gate or lower could be better.

[riptide]

I kinda get that but what I'm really wanting to know is is there an advantage to controlling boost through a maximum usable range with the waste-gate or is it best to take it to a certain boost pressure and let the butterfly control the usage of the boost? ie: is it more useful to control boost from 8psi through 18psi or 12psi through 25psi if you are maxing at say 15psi? Or doesn't it really matter that you can't control the lower range?

I am considering getting a lower pressure actuator. I assume an 8psi actuator will have about an 18psi ceiling???

[Ralph Wiggum]

Go for an actuator rated as close to your intended boost pressure as possible. If your running 13lb max boost I would def go for an 11.9 psi actuator.

With the ported gate and larger flapper mod on my 3566r with not boost controll applied the turbo makes a lazy 11lb's of boost on an 11.9lb actuator. Its very smooth and maintains traction nicely. I can also tune with the EBC im running to produce 15lb's so it comes on like sledgehammer or as smoothly as the wastegate spring only. Talk to your tuner and discuss with him how you want the boost too come on. An 11.9lb actuator wont give you 11lb as soon as you touch the pedal if tuned properly. Dont forget the tension on the actuator can be adjust and this will affect the ramp up rate for the boost.

The problem you may run into with an 8 or 10lb actuator is uneven boost control up high. Dont forget the exhaust backpressure acts on the flapper and this reduces the over all spring tension so you can loose a pound or 2 or effective spring pressure before the boost control solenoid has started feeding boost too the actuator

[riptide]

Cheers Luke, that's the information I was after.

As for setting the tension on the actuator is there any rule of thumb? I had to stretch mine about 4m/m to get it on the flap pin. I set it up exactly the same length as factory.

[Ralph Wiggum]

I generally use a pressure reg and gauge to set them up. Usually cracking a LB or two below spring pressure and full open at spring pressure gives good results, unless you want sledgehammer style boost then set it up so it crack a couple of LB about spring pressure

[riptide]

I recently fitted a GReddy Profec S electronic boost controller. It has a high and low boost setting and works very well. The advantage it has over standard is that it works on MAP rather than a combination of waste-gate cycle time, RPM and charge temp, from what I can tell.

My only regret is that I didn't fit a 10PSI actuator so I can have a nice "nana tune" for the low boost tune as the high setting would probably still be enough to max the turbo out.

I have played around with the boost table and got reasonable results but the main difference/advantage with the GReddy set-up is I can have the boost coming in harder without it spiking when loading up in any gear. It just goes straight to the pre-set boost and stays there.