Will dyno tune eliminate low octane fuel table issue?

[Ruhlman Race Cars]

Will getting a dyno tune eliminate the issue with the low octane fuel table issue where the fuse pull procedure is necessary? I'm scheduled for a dyno tune next wednesday and I wanted to make sure what is and is not done during the tune.

Any info/ experiences would be appreciated.

[Synner]

It can be fixed if the tuner actually does it.

[axis]

Do any of the tuners actually tune out the low octane table? IMO, they shouldn't. It's a fail safe mechanism incase you get bad gas or have to use lower octane, for whatever reason. There's not an issue with the lower octane table, just that some early cars had a tendency to stay in that table once there or were there from the factory. The latter was the case most of the time and the fuse pull was a way to force it back into the high octane table.

[CamaroFemme]

Originally Posted by Synner

It can be fixed if the tuner actually does it.

How? What would I need to ask my future tuner to do to make this happen?

I would think Axis is right - there's ALWAYS the possibility of lower-quality gas somehow getting into your car, and the lower table is the failsafe on that.

[The Stig]

Originally Posted by axis

Do any of the tuners actually tune out the low octane table? IMO, they shouldn't. It's a fail safe mechanism incase you get bad gas or have to use lower octane, for whatever reason. There's not an issue with the lower octane table, just that some early cars had a tendency to stay in that table once there or were there from the factory. The latter was the case most of the time and the fuse pull was a way to force it back into the high octane table.

Exactly. Tuning out the low octane table is the same concept as taking the net out from underneath a tight-rope walker. You may know what you're doing, but what if some punk kid yells "don't fall" while you're up there? Similarly, if someone thinks they are doing you a favor and ends up topping your car off with 87. If you tuned out the low octane tables, well; congratulations because you just won the need to purchase a new motor (possible/worst case).

[Patrick G]

I don't think it's a good idea to make the low octane table the same as the high octane table for a street driven car running pump gas. Smart tuners will modify the octane scaler so the ECM will not be as aggressive in dropping timing down to the low octane table. The real key though, is tuning the high octane table well enough so you don't have excessive spark knock (which drops you down to the low octane table).

[NoUCantDriveIt]

Originally Posted by axis

Do any of the tuners actually tune out the low octane table? IMO, they shouldn't. It's a fail safe mechanism incase you get bad gas or have to use lower octane, for whatever reason. There's not an issue with the lower octane table, just that some early cars had a tendency to stay in that table once there or were there from the factory. The latter was the case most of the time and the fuse pull was a way to force it back into the high octane table.

I haven't found when this was resolved, either by after VIN# or production date. Lots of info on the subject, just nothing about a fuse pull no longer being needed to reset the table. Does anyone know?

[CamaroFemme]

Originally Posted by NoUCantDriveIt

I haven't found when this was resolved, either by after VIN# or production date. Lots of info on the subject, just nothing about a fuse pull no longer being needed to reset the table. Does anyone know?

As far as I know it was never resolved. Keep at least 91 in it and it won't be an issue.

[Padre]

Originally Posted by Ruhlman Race Cars

Will getting a dyno tune eliminate the issue with the low octane fuel table issue where the fuse pull procedure is necessary? I'm scheduled for a dyno tune next wednesday and I wanted to make sure what is and is not done during the tune.

Yes, make sure you tell your tuner that is your expectation.

Leaving the Low Octane table alone is not wise because it will need tuning too with significant mods. Setting it equal to the tuned High Octane table is the easiest solution. You just need to be careful about gas and make sure not all the Knock Retard is tuned out.

I imagine you could do a differential on the High and Low tables (stock) and apply it to the tuned High table for the new Low table. (If that's not convoluted anough. )

Padre

[east TX Muscle cars]

the low act table is there so if the computer sees a TON of knock or a few other issue it goes to that table to save your motor, it is NOT good to have that table up high. usually when we tune a car that table is 6-8* LESS that the high oct table

[thebrainhart]

Yeah, as annoying as it is sometimes, its best to not tune it out, for safety reasons.

A lot of tuners will turn off a lot of things and codes such as catalytic converter efficiency codes, lean/rich codes, O2 sensor codes, etc, instead of changing the testing parameters to be compatible with the long tubes and other mods. Leaving them active causes a pain tuning at times, only because their tune job isn't good enough to work with them. When they turn them off, the computer doesn't run the tests to determine if the engine is running safely or not, either for the engine, or for other components, such as catalytic converters.
There was a big stink a little while ago about cats going bad with long tubes. If they had tunes which enabled proper testing, the computer would have set the SES light, indicating the tune sucked, and is ruining the cats.
Most of the stuff in the factory tune is a pain, but is there for a very good reason.