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HKS Actuator Results on Stock Turbo

Guest Robo's

By Guest Robo's,
in Engines & Forced Induction

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Guest Robo's

Guest Robo's

Posted
Posted

The big question??? Does the HKS Actuator stop boost dropping up high on a stock turboed RB25DET?? The answer is NO.

Initial instalments werent too good, i was having no boost down low and a little up high, say 8psi at 6000rpm, but 5psi mid range was aweful, explains why i struggled against a VR4 owner. But after some more testings, im getting some mixed results. The problem is i am getting 11psi at 3000rpm, then it gradually rises with revs to 13psi and slowly filters off at the top. But i am pulling at least 1psi more up top and yes it is holding it longer. But i cannot get fullboost down low for some reason. Also, i am not using the bleed valve at the moment.

I will do some more testing. I am planning to back the actuator off a little and fit my bleed valve and raise it from there. Then once i've got a reasonable state of tune, i will whack it on the dyno and monitor A/F ratios and boost levels.

To be continued!!!

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R31Nismoid Grand Master

R31Nismoid

Posted
Posted

so your saying you get 11psi @ 3000rpm ?

And you want more down low?

If so, you aint gonna find much more at all. How early do you think the stock turbo will make 11psi? :consfused:

And actuator wont stop the boost dropping off much at all, as the turbo is just getting out of its efficiency. No gadget (save for a better turbo) will fix that problem.

Guest Robo's

Guest Robo's

Posted
Posted
so your saying you get 11psi @ 3000rpm ?

And you want more down low?

If so, you aint gonna find much more at all. How early do you think the stock turbo will make 11psi?  :consfused:

And actuator wont stop the boost dropping off much at all, as the turbo is just getting out of its efficiency. No gadget (save for a better turbo) will fix that problem.

I used to get 13spi with the stock actuator down low.

aqik33 Contributor

aqik33

Posted
Posted

Definately wastegate issue. Critical to this HKS actuator is the rod length. Any small change in the rod length will result in poor boosting.

The bleed valve has like an inbuilt delay which fights the wastegate creep. Running the HKS actuator by itself and u have to expect some creep, thats how its designed to work, smooth boost transition, not WHACK.

I mucked around with carby return springs on the wastegate flap with my old VL turbo. Worked a treat once the right spring was found, ie not to heavy, not to light.

Guest Robo's

Guest Robo's

Posted
Posted
Definately wastegate issue.  Critical to this HKS actuator is the rod length.  Any small change in the rod length will result in poor boosting.

The bleed valve has like an inbuilt delay which fights the wastegate creep.  Running the HKS actuator by itself and u have to expect some creep, thats how its designed to work, smooth boost transition, not WHACK.  

I mucked around with carby return springs on the wastegate flap with my old VL turbo.  Worked a treat once the right spring was found, ie not to heavy, not to light.

Your right, its a smooth transistion to full boost. I can watch the boost guage creep as revs rise. Time to pull the tension back out of the actuator and bleed some boost into her.

  • 2 months later...
tang0 Proficient

tang0

Posted
Posted

stock turbo, stock actuator, HKS EVC IV, and i get .75 bar from about 2800 / 3000 rpm ish, until redline ...

this bring me to conclude that its all in the wastegate control ... yes, the actuator plays a big part in this, but it also need to be told WHAT to do, this is where the EVC comes in and seems to do a GREAT job at it ...

Robo's Mentor

Robo's

Posted
Posted
stock turbo, stock actuator, HKS EVC IV, and i get .75 bar from about 2800 / 3000 rpm ish, until redline ...

this bring me to conclude that its all in the wastegate control ... yes, the actuator plays a big part in this, but it also need to be told WHAT to do, this is where the EVC comes in and seems to do a GREAT job at it ...

Try boosting it further and then watch it drop

Robo's Mentor

Robo's

Posted
Posted
would prefer not to kill the stock turbo until i have another one sitting on the shelf waiting to be installed .....

If you dont race it on a track, lap after lap, its not going to die straight away. Ive been on 13psi for at least a year now, and i have just taken out my turbo last night and its still as tight as ever.

Bass Junky Grand Master

Bass Junky

Posted
Posted

It's more to do with heat in the exhaust wheel.

If you are running stock management you are less likely to bust the thing as you are when running a PowerFC.

When you lean the mixtures you heat up the exhaust gases and therefore the exhaust wheel.

The exhaust wheel delaminates at very high temperature and it spits itself into the turbine housing, hence destroying the impeller.

BASS OUT

sweetr33 Experienced

sweetr33

Posted
Posted

hi flow it or bolt on 2530 or something similar and have no ceramic issues wories, personally i found the stock turbo to be very reliable, i was running 13psi and sometimes 15psi on stock turbo. The oil seal let go and the rear wheel is still all intact although my engine also decided it could handle it anymore so......rebuilding

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