Jump to content
SAU Community

Recommended Posts

  • Replies 50
  • Created
  • Last Reply

Top Posters In This Topic

Thanks for your offer 6boost. unfortunately i havnt checked posts for a while

Based on the backpressure we were pretty sure it was the manifold but not 100% as the power droped off just before the backpressure rose...

Built a new one anyway, based on a well proven design :D

Bolted it up, drove, and hello, NO CHANGE. (I now own 2 manifolds:(

Decided at this stage to rule out and cam timing valve float issues so fitted Kelford RB20DET 272 - 9.35mm cams and uprated valve springs... some change but minor.

Computer is away getting fixed as had a ramdon issue causing the injectors to wildley pulse when the key was turned on - flooding the engine and making it impossible to start. When i get it back I will pressure test manifold and exhaust.

So I still have something causing high back pressure issues killing flow...

*exhaust is 4" straight through

*turbo is GT35 0.82 rear

what am i missing??? this is driving me nuts!!!

will post dyno sheet

cheers rob

post-29626-1208165239_thumb.jpg

post-29626-1208165329_thumb.jpg

Edited by roba

Is the problem with the ECU a random fault with your specific unit or is it a problem with the design of the unit or the firmware it uses? Was it produced by TF Electronics here in AUS?

Regardless of the outcome, 6BOOST's offer is pretty exceptional to say the least and I would jump on it once your problem has been solved. My bet is you'll see even more improvements.

looks like you have the cheap cam gears, they have been known to let go and fully adjust to one side. take the exaust side off, (cas and bracket) and check where the mark is.

I had to replace the allen keys on mine with some bolts because they were screwed....

check that out

Dyno Plot uploaded, first plot is manifold pressure vs boost pressure.

It is not the cam gears, they were checked and adjusted during the tune.

Yeh its a TF electronics unit, I dont know what the fault is but hopefully the dealer who is fixing it does.

230208_dyno.pdf

i agree, it sounds like you have poo IGN timing

check the cam gear, its probably come loose and retarded itself

I think our man has got it right here, my R32 was doing a similar thing, it was the ecu backing the timing off because 1. the knock sensors where not plugged in, 2. the O2 sensor was playing up 3. the MAF was dirty. fixed all that and the ecu stopped retarding the timing. does yours tend to level out at a certain rpm an sturggle to gain revs too?

I think our man has got it right here, my R32 was doing a similar thing, it was the ecu backing the timing off because 1. the knock sensors where not plugged in, 2. the O2 sensor was playing up 3. the MAF was dirty. fixed all that and the ecu stopped retarding the timing. does yours tend to level out at a certain rpm an sturggle to gain revs too?

1 Knock sensors not connected

2 O2 sensor not connected

Correct me if im wrong... these are not accepted/required on this ecu ie. no knock function, and o2 only required for closed loop running for fuel economy.

Dont think its the exhaust as it 4 inch right through with no cat (not rqd in clean green nz) but i will be checking the back pressure when i get the ecu back.

cheers

post-29626-1208247261_thumb.jpg

hey roba

Nice exaust system you have there!!!

Interesting issue your having now. im interested in knowing whats wrong.. if you work it out let me know

actually when i think about it, get a set of stock RB25 cams and whack them in to test it. see if you get any power out of that.

I am not sure that RB20 & 25 cams can be changed around just like that ?

Edited by Guilt-Toy
my money is on the gate set up.

your manifold pressure is raising out of control while your boost pressure is dropping.

Could you explain this a bit further dangerman, i dont really understand what you are getting at.

But i tend to think the restriction is in the turbo/gate setup.

But i cant see how.

ps. the pressure drop is only 1-1.5 psi

after thinking in my thinking chair..

anyway my money is still on the waste gate setup. I really think the first manifold was garbage, i think the design of the last one was a lot better. (i know i have no evidence or actual proof as we cant flow test by looking at it on the net!)

I really think it would be worth while trying a new Ex. housing (same size) and run the gate with a screamer and test again. even if you hate scream, if it solves ur problem, you could plumb it back further in the zaust after testing

hope you sort it mate.

cheers

P.S if i were you i'd take up 6boost up on his offer and bolt a 38mm gate on with screamer!

what happens if you turn the boost up to 20 pound?

i can only think the manifold pressure would rise even higher as boost increases.

looking at the dyno sheet you provided you have nearly 3 x the manifold pressure as you have boost pressure.

i have seen similar set ups to what you have in the past and they have worked ok.

But they may have been installed differently, bigger hole in housing etc.

at the end of the day the external gate exhaust housing isnt designed to have a big ass hole drilled in it and a gate welded on near the outside of the turbine. so total gas flow will never be optimal. i will mention that the other setup's that i have seen have all been low power cheap fixes not designed for massive amounts of air flow.

i personaly would look at manifold #3 having a ex gate outlet and then grab another exhaust housing.

your exhaust cant be causing the pressure increase so there is only 2 things that can.

the external gate, or your exhaust housing.

my finger is pointed at the exhaust housing.

dangerman4 is spot on the money, at 4700rpm where your manifold pressure skyrockets off the chart you can see your torque dips way out and the linear curve of power pans out to a gradual climb instead of a fast ramp upwards. its like the engine cant breathe enough, or its being chocked. so look at the wastegate setup and runners etc on the manifold

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

    • just an update to this, poor man pays twice  Tried sanding down the pulleys but it didnt do the trick. Chucked another second hand alternator in the na car which I got for free off my mate and its fixed the squelling. Must have been unlucky with the bearings.    As for my turbo car, I managed to pick up a cwc rb alternator conversion bracket + LS alternator for 250 off marketplace, looked to be in really good nick. Installed it , started the car and its not charging the battery.... ( Im not good with auto elec stuff so im not sure if this was all I needed to do but I verified such by using a multimeter on the battery when the engine was running and I was only getting 12.2v )   I had to modify the earth strap for the new LS alternator , factory earth strap was a 10mm bolt which did not fit the bolt on the LS alternator which was double the size so I cut it off , went to repco bought some ring terminals that fit, crimped it onto the old earth strap and bolted it up to the alternator , started the car and same issue. Ran like shit and was reading 12.2 at the battery.  For a "plug and play" advertised kit thats not very plug and play but alas.  My question is , am I missing something ? Ive been reading that some people recommend upgrading the stock 80 amp alternator fuse to a 140 amp but I dont see how that would stop the alternator charging especially at idle not under load.  Regardless ive pulled it out and am going to get it bench tested by an auto elec tomorrow but it would be handy to know if ive missed something silly or have done something wrong.   
    • My wild guess is that you have popped off an intake pipe....check all of the hoses between the turbo and the throttle for splits or loose clamps.
    • Awesome, thanks for sharing!
    • To provide more specific help, more information is needed. What Android screen? What is its wiring diagram? Does the car's wiring have power at any required BAT and ACC wires, and is the loom's earth good?
    • So, now all you need to do is connect the 2 or 3x 12v feeds into the unit to permanent 12v, ACC 12V and IGN 12V that you can find in the spot behind the stereo, and the earth, and then it will switch on with the car.
×
×
  • Create New...