High boost (~28psi) with -5s/2530s. what actuator needed for stable boost?

[burn4005]

High boost (~28psi) with -5s/2530s. what actuator needed for stable boost?

Hi Guys,

 

Got a question for those of you that have pushed big boost through low mounts (-5s/2530s etc)

I was using some dual port actuators from turbonetics with a 4 port solenoid in the hope they would provide a large control range for boost control, but they leak on the underside of the diaphram through the shaft hole so cannot hold the wastegate closed at significant boost and they also have a weak spring so are not suitable to just use as a single port. on closer inspection they're not going to work so I'm ditching them for some normal single port actuator cans.

 

the question is, what spring pressure will I need to use to hold 28psi on E85? is the 15.6psi spring of the garrett -5 actuators enough to not have them blow open at high exhaust manifold pressures or do I need to go to a garrett 19psi spring actuator to hold them?

it is a flex fuel car so on 98 I would like to be running around 20-22psi and up to 28-ish psi on E85 if possible.

the other option would be going to dual port turbosmart IWG-75s but they're quite a bit more expensive so would rather not and I'm not sure if they'll fit as they're pretty big.

 

thanks!

[Chris32R]

Are you sure you connected up the dual ports on the turbonetics correctly?

They shouldn't leak if pressure is applied to both sides of the diaphragm as far as I'm aware

[Piggaz]

How big is the engine/how well does the whole system breathe? How much power are you making?

I had my -5's modified to increase leverage on the arm using the garrett stock item. I had them cracking at 24 psi but then brought it back to 19-20 psi. Managed to get it to hit 30 psi through the middle but tapering down to 26ish psi by 8000 rpm. That was making 472 rwkw on Unigroups dyno. (2.8, heavily modified head, big lift cams)

At some point, those little compressors are going to run out of puff/flow. if they cant supply anymore air then naturally the pressure is going to taper off.

 

[burn4005]

Appreciate your input guys.

Used to run the hks actuators but one was leaking so went the turbonetics dual ports.. but unfortunately the actuators shaft seal is a token effort and the spring pressure is around the 7psi mark so they're just not up to it and blow open dropping to 0.9 bar at redline. The turbo smart dual port IWG-75 units would be much better suited and I may investigate making them fit as I'm in for 130 bucks for a garret actuator or 200 for the turbo smart dual port with the option of adding more springs down the track.

Engine is a JHH built 2.6 with headwork, hks2530s proper 3 inch dumps, equal length front pipe and 85mm exhaust, 260 x 10mm cams and PAC beehive springs. Has made 550whp at 23psi in the past. Full boost about 4600rpm.

Want to see how far these hks snails will go for fun really.

A big Efr is a few years down the road if I still have the car

Edited November 9, 2016 by burn4005

[KiwiRS4T]

Ideally you want spring pressure close to max so 19psi spring would be better.

[Shoota_77]

@Piggaz good actuators, shit toes!