Garretts Gt30/gt35 Iw Housing + Actuator Travel Concern

[Cubes]

To dig up a thread.

No issues with overboosting 15.5psi smack on perfectly the actuator appears to be a tad lazy but its apparently a common trait with the Garrett actuator.

I went with Shauns advice and stuck with a bell mouth to prevent boost creep. It has done the trick nicely.

BUT boost drop up top sucks. Its definitely blowing the gate open.

Time to get rid of the small diaphragm Garrett 1bar actuator and in with a large diaphragm 18psi actuator.

[dano4127]

large diaphragm 18psi actuator

whats one of these worth?

could be used on an XR6 3540?

You still running the standard flapper?

[Cubes]

No idea haven't priced one up yet. Expecting 100-200 or there abouts.

The actuators can be used on the gt35's with out problem.

Yes still running the std flapper with a bell mouth its the .82 rear.

[Lithium]

Checking everything over I noticed I have to place a hell of a lot of preload ~9mm on the actuator to get it over the wastegate flaps stud.

Hmm I never checked over mine that closely. Something that has been bothering me is a strange habit my car has - the wastegate opens at ~11psi no matter what. Boost will build sharply until it reaches 11psi, then it acts like the flap has cracked open slightly then boost will build until it reaches the preset amount I am after.

An electronic or manual boost controller does not seem to fix this - it only affects what happens afterwards. If I wind up any more preload on the actuator to alleviate this, it will boost creep past 15psi - it kind of puts me in a rock or a hard place. I will have a proper look at how everything is lined up tomorrow, perhaps I am getting the same thing but my car may be more subject to boost creep.

[Cubes]

Something that has been bothering me is a strange habit my car has - the wastegate opens at ~11psi no matter what. Boost will build sharply until it reaches 11psi, then it acts like the flap has cracked open slightly then boost will build until it reaches the preset amount I am after.

An electronic or manual boost controller does not seem to fix this - it only affects what happens afterwards. If I wind up any more preload on the actuator to alleviate this, it will boost creep past 15psi - it kind of puts me in a rock or a hard place. I will have a proper look at how everything is lined up tomorrow, perhaps I am getting the same thing but my car may be more subject to boost creep.

Its the crap 1bar actuator. Mine lifts off the seat hard at 11psi also. The ebc does help some what though as we have it not allowing any boost to the actuator until around 13psi. It seems to get it past the hump; much less and it will be crapo as you are experiencing.

The difference is huge. Without the ebc 1bar at 4300rpmish. with ~11psi at 3000rpm. Shove the ebc on it and it will make 1 bar at 2800rpm; usually on the street I see 19psi by ~3k.

[Lithium]

Its the crap 1bar actuator. Mine lifts off the seat hard at 11psi also. The ebc does help some what though as we have it not allowing any boost to the actuator until around 13psi. It seems to get it past the hump; much less and it will be crapo as you are experiencing.

The difference is huge. Without the ebc 1bar at 4300rpmish. with ~11psi at 3000rpm. Shove the ebc on it and it will make 1 bar at 2800rpm; usually on the street I see 19psi by ~3k.

Nice. With the AVCR I cannot use 100% duty, and it always creeps open - it effectively makes it take its time to 1bar and is really annoying. It gets to 11psi fairly acceptably and does climb a crapload faster than without the AVCR on, but still. Would an HKS actuator or something like that help, maybe?

[dangerman4]

what you need to do is think about the final boost setting you wish to run at.

dont waste your time having a low boost setting and a high boost setting thats just silly.

pick your desired final boost level say 20 psi, and then get a new actuator as close as you can get to that level.

ie a 18 psi actuator.

once you have that make the shaft to suit the position thats its in so the rod is pulling central on the diaphram and set about half a hole prelaod on the gate pivot.

then you will have good, stable, boost control.

the main benifit i found is boost will ramp up real hard to 18 psi before the gate cracks open so the midrange is improved dramatically.

and by using just half to 3/4 a hole prelaod you will get max travel from the flapper and therfore have good wastgate flow up high in the revs.

[Lithium]

what you need to do is think about the final boost setting you wish to run at.

dont waste your time having a low boost setting and a high boost setting thats just silly.

pick your desired final boost level say 20 psi, and then get a new actuator as close as you can get to that level.

ie a 18 psi actuator.

once you have that make the shaft to suit the position thats its in so the rod is pulling central on the diaphram and set about half a hole prelaod on the gate pivot.

then you will have good, stable, boost control.

the main benifit i found is boost will ramp up real hard to 18 psi before the gate cracks open so the midrange is improved dramatically.

and by using just half to 3/4 a hole prelaod you will get max travel from the flapper and therfore have good wastgate flow up high in the revs.

I know, and that is exactly what I did. I want to run 1-1.1bar (completely stock internal RB25) and in theory its a ~1bar actuator but it lazily creeps open before it reaches 1bar, hence the problem.

Edited August 8, 2008 by Lithium