Jump to content
SAU Community

Recommended Posts

Hi Team!

Have purchased a Rb25GCG turbo for my RB20. The car will be used for street and track, but mostly track, so will be tuned for the one psi setting. Now I no internally gated turbos do suffer from boost control issue, and I am keen to here you thoughts on options for controlling boost. The turbo has not been fitted yet, so I want to get it right from the start

To start with I have purchased a Greddy Profec B Spec II. But with running a standard rb20 actuator I no I will suffer from spiking and boost tapering off at higher revs.

To give you something to work with, I want to run 18psi, no more.

I would like to here your guys/girls opinions on aftermarket actuators. I no brands such as XTR make 18psi actuators, but wondering the reliability. I have heard actuators can suffer and be quite temperament in different weather conditions.

Also what do you guys think of running a 16psi actuator and using the boost controller to hold the last 2psi.

I want to run the boost controller mainly to eliminate spiking, but keen to here any thoughts or options. (Even external gate if you think 18psi actuator is pushing the limits)

Please feel free to flame, as I tried searching to no avail.

Thanks.

Link to comment
https://www.sau.com.au/forums/topic/234074-boost-control-options/
Share on other sites

If its going to be used mainly as a track car i would suggest having an external gate welded to the top of the standard manifold, next best option would be an adjustable internal gate, i have a hks one that works well, that is assuming you are only going to use one boost level.

The problem with all internal gates is that they start to bleed boost before they get any where near full boost, an external gate does not do this and does not have boost flare either.

i got the manifold for 175, gates can be expensive, a mate has one on his turbo xe falcon that is a cheap 60mm ebay job, costs around $150-$200 and he has not had a problem, would probably cost about $500 all up, but when you consider a good ebc will cost you $400+ and an external gate will work a lot better then its not all that expensive after all, plus it will be a good set up when you go an even beigger turbo in the future.

Edited by W0rp3D

Ive just got the Greddy Profec-B spec-ii, installed it myself yay

with the HKS heavy duty actuator, no spike at 1.15 bar. havent tried higher untill after a little dynotune time setup

Id say ditch the rb20 actuator and get a $150 hks heavy duty actuator, with your profec, easy to achieve steady 18psi surely

Yeah. Well no mater what I will have a boost controller as that has already been paid for. I could still run a boost controller with a cheap eBay gate to regulate and prevent spiking. But still interested to see peoples opinions on actuators as it would be a much cheaper solution.

has anyone tried those XTR actuators on http://www.tweakit.net/

?

ive actually been thinking about this very same situation, for a while now.

as i currently have a rb20, and am thinking of going a rb25 gcg hi-flow.

but ive been thinking of not going the EBC just an 18psi actuator. or will that have to much play with weather changes and heat....etc...

ive actually been thinking about this very same situation, for a while now.

as i currently have a rb20, and am thinking of going a rb25 gcg hi-flow.

but ive been thinking of not going the EBC just an 18psi actuator. or will that have to much play with weather changes and heat....etc...

Yes my thoughts exactly.

Another option I have been toying with is using a T3 wastegate adaptor, that sits between the manifold and turbo. That plus an external gate, is that all that is needed to run?

Or do you need to block of the flapper port on the turbo?

Still very unsure which is an ideal way to run this setup.

Yes my thoughts exactly.

Another option I have been toying with is using a T3 wastegate adaptor, that sits between the manifold and turbo. That plus an external gate, is that all that is needed to run?

Or do you need to block of the flapper port on the turbo?

Still very unsure which is an ideal way to run this setup.

i dont exactly get what your saying here, but if your asking if you run a external gate on an internally gated turbo, yea u need to weld the internal one shut.

id rather not run an external gate on this size turbo, doesnt seem very economical, esp for the power these make/amount they flow. im sure you would be able to flow abit more and hold boost abit bettter, but for the amount its going to cost to get it done (with good quality bits) doesnt seem to be worth the coinage. mot to mention all the other goodies you would be able to get to make that extra 5kw. rather get coil packs/cams/more suspension bits... etc....

1) you do not need to weld the wastegate flap shut, the wastegate only opens due to pressure on the diaphram, with no pressure it shouldnt open, a mate of mine did the external gate thing with an internal gate, he had no actuator and just used a spring to keep it closed.

2) the easiest (and dodgy old school) way to adjust your wastegate is to bend the rod, the other way would be to cut it in half and put a thread on each half both in opposite directions (one left hand thread one right hand thread) then get a hollow rod of the right size and put opposite threads in the middle of that, the screw the rods into the middle of the hollow rod when you spin it one way the two inner rods will be pulled together creating more pressure on the diaphram and needing more pressure to open it, turn it the other way and it losen's it needing less pressure to open it.

3) the t3 adapter you mentioned is no doubt the one in the for sale section, 2 problems that spring to mind 1, will this be so big that the turbo now hits the strut tower 2, how will it effect the dump pump and lines since it is pushing the turbo 2-3" out from the engine, but if there is no problems and everything fits then i would go with that option.

4) once again you mentioned boost fluctuation with temps and other factors, the only way to make it accurate is external gate, the internal gate just does not have the flow and accuracy that an external gate has, there is also a big reason why an internal gate costs $100 and an a good external costs $500, you also have to look at the future, no use spending a few hundred on band aid fix's when down the track when you start serching for more power and better response your going to wish you had have gone this way to start with.

These are just things i have learnt over the years, cheap fix's produce cheap results that later you need to spend more money on keeping it going, do it right the first time and your set.

Sry to hijack..

Quick question..

Say I bought a HKS GTRS turbo for my R34 GTT, would getting the HKS actuator make any difference over say, the stock or RB20 actuator???

I'm assuming the HKS unit would be adjustable...

Quick update. Have emailed GCG and they have offered a 18psi actuator, but it is $250 plus shipping,

what are your thoughts?

Wow, didnt expect it to be that steep... might be worth while just to go external then.

The HKS actuator has a minimum setting of about 14psi and is adjustable. The HKS GTRS kit comes with the HKS actuator so a bit pointless to use a standard one on it.

I have one, when i first put it on it was set to 10psi and worked fine, its now just under 14 (.9 bar).

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Even more fun, leave all the ADAS stuff plugged in, but in different locations, hopefully avoid any codes!   And honestly, all these new cars with their weird electronics. Pull all the electronics out Duncan, and just shove an aftermarket ECU and if needed a trans controller in, along with a PDM. Make it run basic but race car styled!
    • To follow up a question from earlier too since I had the front bar off again (fking!) This is what is between the bumper and the drivers side wheel And this is the navigator side, only one thing but its a biggy! So basically....no putting coolers in the wheel arches without a lot of moving other stuff. Assuming I move to properly race prepping this car I'll take that job on and see how the computers respond to removing a whole bunch of ADAS modules
    • So I prepped the car for another track day on Wednesday (will be interesting to see coolant temps post flushing out and the larger reservoir, with a forecast of 3-14 being 20o cooler than last time I took it out). Couple of things to mention; since I am just driving the car and not taking a support vehicle, I took the rear seats out and just loaded the back up Team Trackday style. Look at all that space! To cover off removing the rear seat....it is weird (note the hybrid is probably different because it wouldn't have folding rear seats) Basically, you remove the lower seat base, very similar to a r series but it is a clip that pulls forward to release the base rather than it being bolted down. Easy Then, you need to remove the side section of the rear seat on each side. There is a 14mm head nut at the bottom of the side piece, the it slides upwards off a hook at the top to release; you also need to unhook the seatbelt from the loop at the top. Then the centre piece is weird. You need to release/fold the seats forward with the tab in the boot on each side From there, there are 2,x12mm headed bolts holding the rear of each seat to the folding bracket, under the trim between the rear seat and the boot (4x christmas tree clips there, they suck). The seat is out but you can see where the bolts attach to the bracket
    • As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
×
×
  • Create New...