Fluctuating Tunes

[jordak]

What causes custom tunes to fluctuate / lose power over time.

Does it occur as a result of some of the tuning parametres being too close to the knock sensor margins?

[Street Tuner]

A good tune is one that adapts to the atmospheric conditions and the fuel quality in the car. All of which can and will give fluctuating power outputs depending on the scenario of the dyno run. Its the tune that plods out the same power time after time without protections and corrections in place that is a danger to the mechanicals.

[jordak]

A good tune is one that adapts to the atmospheric conditions and the fuel quality in the car. All of which can and will give fluctuating power outputs depending on the scenario of the dyno run. Its the tune that plods out the same power time after time without protections and corrections in place that is a danger to the mechanicals.

<{POST_SNAPBACK}>

So is it fair to say that if a tuner is hell bent on getting big numbers it can be easier for him to do so by tuning "around" the built in protections I.e. disengaging the the knock sensors whilst tuning?

[Guest]

A good tune is one that adapts to the atmospheric conditions and the fuel quality in the car. All of which can and will give fluctuating power outputs depending on the scenario of the dyno run. Its the tune that plods out the same power time after time without protections and corrections in place that is a danger to the mechanicals.

<{POST_SNAPBACK}>

So is it fair to say that if a tuner is hell bent on getting big numbers it can be easier for him to do so by tuning "around" the built in protections I.e. disengaging the the knock sensors whilst tuning?

<{POST_SNAPBACK}>

Seems as though this could be the case

vik...rather go for a safe tune than large numbers myself

[Street Tuner]

So is it fair to say that if a tuner is hell bent on getting big numbers it can be easier for him to do so by tuning "around" the built in protections I.e. disengaging the the knock sensors whilst tuning?

<{POST_SNAPBACK}>

I personally disengage the knock sensors when tuning the engine on the dyno. The whole concept is to give the engine an ignition timing table that doesnt ping (I.e. its right), and then turn on the knock sensors at the end as a fully functional engine protection mechanism. To tune with the knock sensors engaged may give the situation where the engine is riding the knock sensors the whole time, which in turn reduces engine protection on the street.

It is my belief that any tuner that goes searching simply for a big power number (unless the car is being built specifically for dyno competition work...and even then...whats the point) particularly from an XR6T in stock guise, is an imbecile.

[Adam]

Martin I've had my ute tuned using that exact process you describe above.

After the knock control was turned back on it dropped 25rwkw's and there was no sign of pinging and AFR's were spot on. After that my knock control was adjusted to be less aggressive. From all indications I'd say it's lost that 25 again though.

Any suggestions would be appreciated?

[Street Tuner]

Sorry Adam the batteries are flat in my crystal ball, so guessing whats wrong with your car will be fraught with danger. I would suggest that you go and see Nizpro again and put the car on the dyno. Seat of the pants power gains/losses are generally difficult to gauge correctly without the right tools. Being the only tuner I know of to have in cylinder combustion pressure analysis gear Nizpro now have the functionality of altering knock sensor gain tables (sensitivity) to suit your engine. This should help you

[Adam]

I'll be back at Nizpro shortly.

I didn't use my bum-o-meter, 1/4 mile told the story last time, dyno just comfirmed it.