RB25 runs like

[Dori!]

Hi everybody

Still in France but the date when I'll be flying to Ireland is approaching

I have a problem with the car of a friend of mine, it's an R33 GTS. It is fairly standard, appart from FMIC + intake + exhaust, and we have an issue with what we think is igniting timing.

When we keep boost standard (i.e. 0.6 - 0.7 bar) everything goes fine.

Once we raise the boost, the car will accelerate like crap. We can go up to 1 bar for example, the driving feels fine but the car does not accelerate like it should. Boost keeps steady at 1 bar, AFR is good (11 at wot), but well, the car does not accelerate. It even accelerates better if we keep it standard. It looks like ignition timing gets retarded like hell, but why ?

We changed the ignition (plugs / cords / coils), the AFM, next we will try knock sensor...

Any idea that could help us ?

[nissan_doctor]

What other mods are on it?

You cannot run 1 bar on either the standard fuel pump(would cause severe underfueling, knock, ignition retardation) or the standard turbo. The standard turbo will fail prematurely if running at 1.0 bar any length of time.

Also if you are trying to run higher then standard boost then you need a colder heat range spark plugs.

[Dori!]

What other mods are on it?

You cannot run 1 bar on either the standard fuel pump(would cause severe underfueling, knock, ignition retardation) or the standard turbo. The standard turbo will fail prematurely if running at 1.0 bar any length of time.

Also if you are trying to run higher then standard boost then you need a colder heat range spark plugs.

Oh yeah I forgot, there is 300 liters/hour fuel pump with cold plugs. Turbo is standard.

[nissan_doctor]

Ok, well I still wouldn't be trying to run 1.0 on the factory turbo.

The factory ecu should be able to run the set up reasonably safe up to 0.9 bar. Have you been able to check the base timing on the engine?

The cas sensors do give trouble on them and it will be even worse if the base timing is off too.

[Dori!]

We tried 0.8, 0.9 bar also, but the result is the same. My friend already blew up a turbo during a rallye by running around 0.9-1 bar (the exhaust part went all the way through the exhaust, lol), but the car always had this problem since he's been owning it.

Base timing seems ok but we had a bad strobo to check it, I'll try to borrow a better one to make sure. Do you know if there is a way to monitor timing while having a test run ?

We'll swap the CAS sensor and I'll let you know.

Thank you very much