HKS Actuator Results on Stock Turbo

[Guest Robo's]

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!!!

[R31Nismoid]

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.

[Zombie]

I have had great experience with my garret actuator. Holds 15psi really well but does drop off to 13psi up high in the rev range, but that is, as R31Nismoid said, the turbo getting out of its efficiency.

Adam

[Guest Robo's]

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.

[R31Nismoid]

i'd be well happy with 11psi at 3000rpm

[aqik33]

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]

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.

[Bass Junky]

So what are the further results.....

[sweetr33]

date???

[Robo's]

Latest, stock actuator back in place now reaching full boost of 13psi at less than 3000rpm.

Latest on the HKS actuator, ready to test on a HKS 2530.

[tang0]

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]

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

[tang0]

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

Try boosting it further and then watch it drop

[Robo's]

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.

[tang0]

just don't want to take that chance at the moment, it seems that a rule of thumb is .75 for a stock turbo ... as with everything there are exceptions to rules, but just dont want to take that expensive chance, yet ...

[Bass Junky]

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

[Robo's]

My A/F ratios at the moment are around the low 12's, so its not running rich at all, probably a bit lean at the moment

[sweetr33]

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