Jump to content
SAU Community

Recommended Posts

  • Replies 61
  • Created
  • Last Reply

Top Posters In This Topic

what series rb26 is it because it looks like an rb25 to me ?

RB26 breather hoses are towards the rear of the cam covers and the covers have different curves on them. So I think you're right. Or its an RB26 with its cam covers swapped.

help, fwiw, I prefer pnuematic boost control too.

Guest INASNT
RB26 breather hoses are towards the rear of the cam covers and the covers have different curves on them. So I think you're right. Or its an RB26 with its cam covers swapped.

help, fwiw, I prefer pnuematic boost control too.

hmm true, didnt spot that.

Y would u swap cam covers???

Could this be part of power problem ? and that T-piece boost controller, they can only handle a certin amount of boost before they do what they want.

eg: it can only hold upto 14psi intill it canrt hold it any more and the boost will go all over the place ? that why i said turn the boost right down and see if it works any differnt.

at a guess its a 1.0 rear housing...

get a few places to look at it as a basic engine checkup and see if they all concur similar idead about your car... i know this is money but it will iron out most of the probs...

forget the t piece to although its not ideal the car still runs 22psi, agains boost controllers affect response and delevery. if the gauge is running from the plenum and it reads 22 psi then the bleeder is working in creating this boost... in responding we need to remember its not that he cant make boost its that the power figure for that boost reading isnt right which means its a ignition issue ie. the fuel isnt being lite, or a fueling issue theres not enough or theres to much fuel... look at this would be my advise to you get a better tuner someone who knows haltech, go to haltech.com.au or something and look up there distributers for your area im sure most of them are workshops with dynos use one of them to tune the vehicle. theres also a forum on the site you can ask whos the best in your area!!

Trust me it is an RB26 I will take a picture of the engine number if you like :) I did that for the exact same reason you guys were argueing. Open the bonnet it just looks like a 25 but it is really a 26. Before I blew my 25 however I did have a gtr plemun and throttle bodies fitted to the car so for those who have asked it can be done just need and adaptor plate made up. It made the throttle heaps more responsive on the 25, I think it was worth it you can get the right people to do the work. RNS11Z thanks for you're help mate I will give him a call today. Thanks for the help guys i will keep you posted on what is happening. Are most of you guys running power fc's and has anyone ripped out and old computer to put in a new had any problems.

Guest INASNT
Trust me it is an RB26 I will take a picture of the engine number if you like :) I did that for the exact same reason you guys were argueing. Open the bonnet it just looks like a 25 but it is really a 26. Before I blew my 25 however I did have a gtr plemun and throttle bodies fitted to the car so for those who have asked it can be done just need and adaptor plate made up. It made the throttle heaps more responsive on the 25, I think it was worth it you can get the right people to do the work. RNS11Z thanks for you're help mate I will give him a call today. Thanks for the help guys i will keep you posted on what is happening. Are most of you guys running power fc's and has anyone ripped out and old computer to put in a new had any problems.

sure u havent been jibbed by the guy that did the convertion??? You cant fit rb25 covers to the rb26, they dont sit on there properly.

I got a PFC and have had no problems with it.

Is anyone here making over 300KW with a halteck on board, if so did you have any tuning problems/sensor problems. What are you guys using computer wise to make good power.

i fink u r using the wrong computer for an rb26 motor...u need something that tunes through throttle position the e6k does not have this feature.... it will thus be running super rich on cruising and possisbly making it feel like a nugget to drive... the mictotech mtx12 or something like that tunes through throttle position or y not go for the e11 which i would recomend for a rb26 ..... hope this info can help.... call adam from JEM in sydney he can tell you what u need to know about haltechs (02) 96006567 correct me if im mistaken :wavey:

i know of a few skylines making over 300rwkw with a haltech

good point amu but this doesnt matter as it is not making power as opposed to not cruising nicely.... WOT is WOT if the computer knows that, which it does, then its tuning and so forth... help, go for your real problem as i have stated before your car isnt making numbers at 22psi... it makes 22psi so theres no turbo related problem the problem lies between where your boost gauge is plumed and the exhaust ports!!!!

Hi Help, I'd like to start with the wastegate, I have pretty good success using this formula to determine external wastegate sizes;

Airflow in lbs per minute = diameter of wastegate in mm X boost correction factor

So let's apply it to your car;

300 rwkw = 480 bhp

480 bhp = 44 lbs of airflow = 44 mm wastegate

Now if you want to run 19 psi, then that's the right size wastegate.

But we need to apply the boost correction....

My experience indicates that to get 300 rwkw out of a GT3040 you would need to run around 1.5 bar (22psi). So using the formula...

44 / 22 X 19 = 38 mm.

For those who haven't read the thread..............

http://www.skylinesaustralia.com/forums/sh...light=wastegate

So I would say that your wastegate is too big, what this means is it has to open and close more often, as it has too little exhaust flow when closed and too much exhaust flow when open. All this opening and closing of the wastegate affects the amount of exhaust flow though the turbine, this leads to fluctuations in the boost control. eg; I have seen a relatively low powered engine, with a very large wastegate, move up and down 0.3 bar in its boost as the boost control circuit struggles to keep up with this open, closed, open, closed requirement.

Moving on to one of my favourite subjects, the wastegate actuator spring rate. If you want to run 22 psi then you should have an 18'ish psi spring in the wastegate actuator. That way the boost controller only has to control the 4'ish psi. If you have say a 12 psi spring, then your boost controller (doesn't matter what type) is struggling to keep up with bypassing (or pulsing) the required amount of pressure (10 psi) to control the boost.

Summing up, I think you have 2 problems, the wastegate is too big and (most likely) you have too light a spring in the wastegate actuator. Consequently I am not at all surprised that you have boost control issues. The bypass style boost controller is probably not helping, but it isn't the cause of the problem.

So the very first thing I would do is make sure you have at least an 18 psi wastegate actuator spring. If not then get one, I reckon it will fix most your boost fluctuation problem.

Lastly, too big a wastegate, since it seems to run OK at low boost and makes good power there, that would confirm the calcs that the wastegate is too big. I would try the spring mod first and if it is still a problem then look at trying a smaller wastegate.

Hope that makes sense.

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

    • As far as I can tell I have everything properly set in the Haltech software for engine size, injector data, all sensors seem to be reporting proper numbers.  If I change any injector details it doesnt run right.    Changing the base map is having the biggest change in response, im not sure how people are saying it doesnt really matter.  I'm guessing under normal conditions the ECU is able to self adjust and keep everything smooth.   Right now my best performance is happening by lowering the base map just enough to where the ECU us doing short term cut of about 45% to reach the target Lambda of 14.7.  That way when I start putting load on it still has high enough fuel map to not be so lean.  After 2500 rpm I raised the base map to what would be really rich at no load, but still helps with the lean spots on load.  I figure I don't have much reason to be above 2500rpm with no load.  When watching other videos it seems their target is reached much faster than mine.  Mine takes forever to adjust and reach the target. My next few days will be spent making sure timing is good, it was running fine before doing the ECU and DBW swap, but want to verify.  I'll also probably swap in the new injectors I bought as well as a walbro 255 pump.  
    • It would be different if the sealant hadn't started to peel up with gaps in the glue about ~6cm and bigger in some areas. I would much prefer not having to do the work take them off the car . However, the filler the owner put in the roof rack mount cavities has shrunk and begun to crack on the rail delete panels. I cant trust that to hold off moisture ingress especially where I live. Not only that but I have faded paint on as well as on either side of these panels, so they would need to come off to give the roofline a proper respray. My goal is to get in there and put a healthy amount of epoxy instead of panel filler/bog and potentially skin with carbon fiber. I have 2 spare rolls from an old motorcycle fairing project from a few years back and I think it'd be a nice touch on a black stag.  I've seen some threads where people replace their roof rack delete with a welded in sheet metal part. But has anyone re-worked the roof rails themselves? It seems like there is a lot of volume there to add in some threads and maybe a keyway for a quick(er) release roof rack system. Not afraid to mill something out if I have to. It would be cool to have a cross bar only setup. That way I can keep the sleek roofline that would accept a couple bolts to gain back that extra utility  3D print some snazzy covers to hide the threaded section to be thorough and keep things covered when not using the rack. 
    • Probably not. A workshop grade scantool is my go to for proper Consult interrogation. Any workshop grade tool should do it. Just go to a workshop.
    • In my head it does make sense to be a fuel problem since that is what I touched when cleaning the system. When I was testing with the fuel pressure gauge, the pressure was constantly 2.5 bar with the FPR vacuum removed. When stalling, the pressure was going up to 3.0 bar (which is how it should be on ignition).
    • ECUtalk pages don't mention they support the ABS computer (consult port has more than one CAN), so you might just need a different scan tool. But, I would expect ABS is a different light to the brake warning/handbrake light, do you see an ABS light come on for a few seconds when you turn the key from ACC to IGN? But since you said: I'd have a look at the ABS sensors in the rear hubs to make sure they are not damaged, disconnected etc.
×
×
  • Create New...