speed rII

Just got back from the dyno, the car made 184.9kw on wheels.
This seems a bit low?
The problem is that secodary boost is going up and down between
0.65bar and 0.85bar? What could be causing this?
Mods on my car..

-pfc
-v-mount ic
-300zx tt fuelpump
-intake
-midpipe, catback and jdm downpipe

twisted7

iTrader: (3)

Have you compression tested the motor?

speed rII

No, engine idles and run normal when the primary turbo is only used.
So, some mod think its exhaust leak?

DaleClark

iTrader: (55)

Do you have fresh plugs? Looks like you're getting ignition breakup on the top end.

Also, get the new updated coil pack harness - the old ones can cause problems similar to that. Less of a boost problem and more of a spark problem.

Start with the basics first .

Dale

speed rII

Plugs have about 500km, on track use only.
Would the brake up feel the same way in rotary and piston engine?
I mean that the engine pulls strong but pulsing with the boost...
No misfires or sharp stops.

Dudemaaanownsanrx7

iTrader: (23)

yeah ignition breakup and fuel cut outs can feel similar. both will also effect the boost because its like your letting off the gas on and off. so check both the fuel and ignition problems before suspecting the turbos. ignition break up is more of a problem at higher rpms and higher boost pressures also.

speed rII

Checked the coils, plugs and wires today.
All was ok, chanced the wires anyway, still the same issue.
Revired the fuel pump to continous 12v, nothing chanced (exept the idle afr :P)
Could the wastegate solenoid be the problem, if its sticking or binding, could this cause the boost to go up and down?
Is there safe boost/fuelcut setting in pfc? I did not find it on datalogic...
Allso tested if the car was knocking (and thus in safemode), no the knock readings were 4-6 in wot pull.

all the way to redline.

RLaoFD

iTrader: (6)

What is your boost supposed to be set at??

Even boosting .65 bar you should be seeing numbers closer to 300whp instead of ~245whp with your mods.

speed rII

Boost should be 0,8bar, on the pfc settings.
I know that im missing 50hp... But first i must get the boost stable, then find the lost ponies.

scotty305

iTrader: (2)

Have you experienced anything like this while driving the car? Does it feel like a smooth loss of power (as if you were modulating the gas pedal), or a sharp quick loss of power (like a rev limiter)?


Have you tried adjusting boost control settings in the PFC, maybe even disabling the wastegate solenoid?


Are you monitoring fuel pressure?

speed rII

The symptoms are the same on dyno and road, and yes its a smooth powerloss.
Like lifting small amount the throtle and then depressing it again.
Im planning to move the fuelpressure gauge outside of the hood so i can see the pressure when driving.
On idle the pressure rises to 9 bar when i pinch the returnline closed.
For the pfc settings and wastegate solenoid, not tryed yet but ill see if the those fix the problem.

fendamonky

iTrader: (6)

245whp is a fine number for near stock boost on the dyno he is using. A lot of european power figures seem much lower than what we, in America, base our standards off of. This is due to the dyno's used predominantly over here returning a lower number (15%-18%) than the ones used mostly in the states.

It's the reason I specify in my sig that my numbers (325rwhp @ 1.1bar) are from a DynoDynamics brand Dyno, and also the same reason the first thing I ask people from europe wondering about low numbers is what kind of dyno they are using.

Before I had my car mapped the first time I was showing 247rwhp with a PFC (base mod map), intake, GReddy SMIC, DP/hi-flow cat/Apex N1 dual and reliability mods at 12psi.

I wouldn't fret too much over the power level at this point, though (mods dependent) with a good tune he should be able to expect around 280rwhp @ .85 bar.

speed rII

Thanks for everyone that helped to fix this problem.
I lowered the pfc dyty setting to 50 and it seems to do the trick.
Only thing that puzzles me, is that the car havbeen working on the first settings.
So is the problem solved, or is it just lurking somewhere in enginebay so it can jump out on my face again

And fendamonky, thanks, now that the car is running good, it feels more powerfull.
On a *** dyno it feels like 30hp more

scotty305

iTrader: (2)

Glad you got it figured out, my car felt a bit like that when I was adjusting the boost control settings in my EMS (not a PFC, though).

I had my EMS configured to change the wastegate duty cycle too quickly, the boost would get a little too high and the EMS would drastically decrease the wastegate duty cycle. The boost pressure would decrease quickly and the error control would drastically increase the duty cycle, letting the car overboost again. When the boost pressure fluctuated, there was a very smooth loss and regain of power, it felt like the driver was gently modulating the throttle from 80-100%.

What ended up working well was decreasing the aggressiveness of the error feedback, and slowly adjusting the base duty cycle settings (10%, 20%, 30%, ...) to find what boost pressure resulted from a certain wastegate duty cycle.

RLaoFD

iTrader: (6)

I'm curious to see how much whp you've actually gained.

speed rII

Dynoed the car today, 214,1kw on wheels. So it gained about 45hp.

The injector dyty is 93% and boost 0,8bar

Ill post the dynochart soon as i get it on my computer.

The dynos wideband showd a little lower afr:s than my cars innovate,
afr is about 11 to 5000rpm and rises after that to 11,2-12,2 no knock tho.
But i think i need bigger injectors.
After 5000rpm the afr is fluctuating so there might be some problem with the secondary injectors?

Zhé

iTrader: (2)

wat size r your injectors?

speed rII

Stock.