Self Learning Ignition

[Mildman]

Yeah I wouldn't doubt with a modified ignition map that you could take advantage of higher than 95RON, as long as you buy it from a high volume station...as I have been informed that the higher octane fuel has an expiry date essentially - thus there will be more variation in higher octance fuels. I imagine this could be trouble if you ignition advance / boost are tuned right on the edge assuming a pure fuel.

I'm waiting to hear back from my bud the engine cal guy re: if the stock computer can do anything with 98RON+ or if it was just the variation that worried him.

Depending on how the edit works I can't see why it could not still take a signal from the knock sensor and retard the timing accordingly...I don't know how sophisticated the edit mapping is....I'm sure someone else does though.

[IH8TOADS]

Well no difference down the 1/4 with 95 and 98 for me. No economy difference either.

[IH8TOADS]

Std ford tune by the way.

[Adam]

  Mildman said:

Depending on how the edit works I can't see why it could not still take a signal from the knock sensor and retard the timing accordingly...I don't know how sophisticated the edit mapping is....I'm sure someone else does though.

I still don't think you get it.

The PCM after editing will work just like it did before, the program is still basically the same with all the same features. The tuner has just changed the values in the tables to suit whatever it is they've done.

So the knock sensor will work just like it did before as long as it hasn't been disabled.

[Mildman]

  IH8PORK said:

Well no difference down the 1/4 with 95 and 98 for me. No economy difference either.

<{POST_SNAPBACK}>

Seems to support my theory...what's the price difference between 95 & 98 at the moment.?

[kawerx]

  XXXR6T said:

Obviously modified will be different, such as edit... it is tuned to run on the higher octane fuel  and using lower will mean it is going to retard timing more often due to knocking.

I would think it takes longer for the stock tune to adapt to fuel though... when you get a re-flash from the factory it will take about 1000km to get to full potential, I have experienced this several times (and even with the EDIT you can notice the difference after 1000km).

I believe the ba ecm have both long term and short term memory.this may explain why it can take 1000 clicks to adapt to new fuel.I thought high octane fuel had a longer shelf life over unleaded?

[Adam]

Yes, I believe the PCM has short term and long term memeory tables for things like fuel trim and knock.

Short term tables are erased when the PCM is reflashed.

Long term tables are erased when you disconnect the battery.

[Mildman]

Just got the following quote, from Something about fuels

"We have heard rumours of the Shell Optimax having only 22 days shelf-life compared to the BP Ultimate 43 day shelf-life, meaning by the time it's manufactured to the time it gets transported to the bowsers, then into your tank and used up, it's shelf-life is almost up, meaning you are using fuel which is almost off ... and yes, just in case you didn't know, fuel definitely does go off!!"

In either case....you pull into a country servo and pick up some premium that has been sitting there a few weeks - you might not be getting what you payed for.

Edited 06/03/06 12:30 PM by Mildman

[Mildman]

My engine calibrater friend has gone futher to say that no Aussie car is calibrated for 98RON, and furthermore due to the lower volume of sales on 98RON fuel it is likely to be close to off when you buy it....

Not sure about japanese cars, but only the sports type euro cars are calibrated for fuel better the 95RON, it's probably the same case with Jap cars too.

Maybe with edit/unichip the calibration takes advantage of 98RON fuel, but with the fuel variability issue you'd want to make sure your fuels good, or the knock sensors are still active and can retard ignition.

[Guest FatBAt]

  RAPHOON said:

  Mildman said:

Hey all,

He goes on to say that 98RON and 100RON are not worth putting in the tank, and to stick with a servo with high fuel turnover for my 95RON.

<{POST_SNAPBACK}>

Thanks for the info Mildman.

You should ask you contact to drive in a modified car and still stick to this statement........

<{POST_SNAPBACK}>

Who mentioned anything about a modified car?

If you buy a stock T just to have a bit more sting than a standard car, why would you want to run it on anything else but 91. If it don't ping, yer save yourself a lot of money.

Not everyone wants a squillion horsepower.

Cheers