Rb30det - Missing 100kw

[WARLORD]

sorry to say but if you listen to anyone from the forum thats your first mistake,i did that once.go see someone who can find it by seeing your car not guessing .

[roba]

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

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

Edited April 14, 2008 by roba

[roba]

PS. Is there any way the computer could be causing this?

I dont see how, but my engine builder (not tuner) likes to swear and curse about 'that bloody computer'

(autronic SM4 plug and play)

cheers rob

[Mr. Untouchable]

damn what a pain in the a$$

I Havent seen many cars with the same gate setup you are runnning... could be that maybe?

[2rismo]

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.

[Guilt-Toy]

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

[paulr33]

i agree, it sounds like you have poo IGN timing

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

[roba]

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.pdfFetching info...

[Guilt-Toy]

drop the exaust at the end of the front pipe. before the cat. and run it on the dyno and see what happens.

could be cat??

[Pun4N1]

  paulr33 said:

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?

[roba]

  Pun4N1 said:

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

[Mr. Untouchable]

holy shit I could drift a bus thru that.

i highly HIGHLY doubt thats ur problem!

[Guilt-Toy]

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 April 15, 2008 by Guilt-Toy

[dangerman4]

my money is on the gate set up.

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

either try a manifold that has a gate outlet built into it or switch to internal gate.

[rb26s13]

haha definately not the exhaust thats the restriction beautiful exhaust system

[roba]

  dangerman4 said:

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

[Mr. Untouchable]

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!

[dangerman4]

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.

[Guilt-Toy]

how hot does the exaust manifold get when you run it on the dyno ? does it get red hot very quickly ?

do you have a dyno sheet of your boost curve?

[paulr33]

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