Dyno Tuning?...

[Anquetil]

Just wanted to know what sort of tuning can actually be done to say a RB25DET when you only have the stock ECU?

When I first started reading these forums I was under the impression (and i'm sure others still are) that the the factory ECU could be retuned by anyone

But I soon realised that it can only be done if you have a remapped/rechipped ECU or you have a PowerFC etc...

My bosses brother owns an Ultra-Tune outlet, so I can possibly get a significant discount or even free dyno time.

I know what some are saying "Ewww! Not UT!" But hes no spring chicken when it comes to Jap Imports having tweaked his own RX7 and his brothers S14.

So, allot of people mention getting their cars tuned but what is actually tweaked when you have a stock ECU... A/F ratio's, timing?

[silver33]

Good question Shane.

I would also like to know the answer to this.

[Anquetil]

Surely someone has some info?...

[predator]

Timing, idle speed, that is about it as far as I know... the ECU adjusts most things internally to keep everything running smoothly. Like most modern cars, its pretty much self-tuning. But while jap cars are pretty flexible in adapting to a few modifications (such as a bit more boost, greater air intake, better exhaust), once you go beyond this basic 20% or so, you're starting to go beyond what the original ECU was designed to adapt for.

Most people run some sort of aftermarket fuel management (such an S-AFC, or like you say, a full aftermarket ECU) to be able to really tune the car to its full potential.

Don't think the dyno will be that useful until you really start getting into that side of things.

[Duncan]

I found 2 things useful in a recent dyno run.

1) power vs rpm, lets ou know when to change gears for best power (and its 6,500, not the redline)

2) Confirm that the AFRs are safe

[JimX]

A second hand S-AFC is probably the best bang for buck tuning tool you have available for an R33. It should cost around $350 (I just sold mine for that, heh) plus $150 for tuning, and you will have an easy 20 extra rwkw, not to mention smoother running and better fuel economy.