Funny Surge.

[WogsRus]

Well ok so my R33 has been funny, allong with some other issues, like cold start.

No idea what is going on. The car has been tuned and so forht, and runs great normally. However, i have some funny surge with the car. At 2500 rpm, in second if i floor it, boost comes up to 14 psi, as preset, and the car kinda surges, well it accelerates, then stops a bit, goes to 3500 and takes off agian and stops a bit, and then form 4500rpm it's fine, no issies at all.

What can this be, It only doe sit on higher boost settings.

BTW the turbo is stock, and i don't normally run it at 14 psi. Car mods as per my sig.

[Dale FZ1]

Showing my ignorance, but what is a Central 20 ECU?

Sounds a bit like electronic intervention to me.

[DjeMz]

Central 20 is a chipped, and remapped ecu from jap

[Gazee]

Showing my ignorance, but what is a Central 20 ECU?

Sounds a bit like electronic intervention to me.

2 much fuel or missfire? r33's normally run rich on higher boost... i had the same problem with my car so i turned it down and left it what it was tuned at lol

[Dale FZ1]

How about failsafe?

Maybe they've retained/modified some of the protection parameters. The AFM reports flow voltages in excess of what is deemed "safe" by the tuners, pushing into map cells that they say it shouldn't do if operating at a certain boost level.

Then it just goes through a series of rich/retard steps to discourage the driver. Guys running stock ECU report the same phenomenon but generally at lower boost.

[WogsRus]

Yeah i guess that sound fesable, as is, after 4500rpm or probably a bit lsee, the car will be fine. So maybe it still has some inbuilt protection.

[blind_elk]

It's probably "compressor surge", caused by the fact that the engine has not been tuned to ingest 14psi of air.

[Dale FZ1]

Compressor surge has nothing to do with an electronic tune.

It is about the physical inability of the engine to ingest the mass of air that the compressor is delivering. It is generally associated with big compressors and small capacity engines running a bit of boost. Garrett offers a really informative tutorial here http://www.turbobygarrett.com/turbobygarre...bo_tech103.html to explain the phenomenon.

Original post indicated a stock turbo, running higher than stock boost. Very very unlikely to be surge @ 14psi.

Edited March 6, 2007 by Dale FZ1

[Tangles]

Buy a Z32 air flow meter and retune the safc to suit?

tune it at say 12psi and keep it there (stnd turbo)

or tune it at 14psi, your call

If you want 14psi talk to Slide about a highflow

that'd sort out alllll the issues, Im sure

* could possibly be the stnd afm maxxing out at the points you mention..................

[Green_s13]

just wondering what fuel pump you have in the car, i had similar issues with a failing fue pump in a silvia

[Dale FZ1]

tune it at say 12psi and keep it there (stnd turbo)

or tune it at 14psi, your call

If you want 14psi talk to Slide about a highflow

that'd sort out alllll the issues, Im sure

* could possibly be the stnd afm maxxing out at the points you mention..................

I'd agree there is a good chance of failure if he's wanting to run it at 14. I wasn't prepared to run mine any higher than stock, knowing that elevated speeds would eventually result in the turbine rotor parting company with the shaft.

Slide's product would be a useful upgrade, but quite frankly a useless change unless the ECU is able to support it. And it seems that the ECU currently won't handle the mass air flow capacity of a stock turbo @ 14psi.

It's not a case of the AFM "maxing out" though, just exceeding tuner defined parameters within the ECU settings at those lower engine speed ranges.