[GeorgeRex]

I am wondering what is the real importance of rescaling COBB ST maps? If you hit a hypothetical load of 3.4 for example, does the ECU do a linear interpolation from the last load value such as 2.75?
Is the value of rescaling so that you can achieve greater control or non-linear value progression or both?

I am hitting load values of 3.52 on my standard ST maps which stop at 2.75 load and have not experienced any problems.

I have been trying to rescale maps posted by TMS but can't get Excel to do it right. When I use auto fill on a declining value row, the first value in the new column is higher than the last one in the existing column. e.g. 15,14,13,12,11,12,11... If someone could post a tutorial with screen shots, that would be awesome.

Cheers,
GR

[daemon]

The value of rescaling is so that you actually have control of the timing/fuel/etc. at the values you are hitting. If you are hitting 3.52, but the maps only go to 2.75, you are losing a lot of control in areas were you could better fine tune. Just because you don't doesn't mean you will necesarily have a problem if you tune the 2.75 to what you want at 3.52, but you are losing a lot of resolution.

My understanding is that the ECU will use whatever the value in the last column is for any load past that column. So it isn't interpolating anything, but using the value as-is. I could be wrong about that, just what I thought I read a while back.

I'm not exactly sure I understand the problem you are having with Excel. When I rescale mine, I just change the axes values by hand. FWIW, you can also use the StreetTuner interpolate function keys (h and v) on the axes.

[reid-o]

I had this dilemna on my AEM, as engine management is engine management.

Generally, if you're looking at peak horsepower and dyno runs or drag racing, since you're only tuning the last load points, it's much easier to tune, and honestly, you won't make really make more power by rescaling.

The benefit, I think, comes when you're tuning for variable weather conditions, and or load situations, such as in road racing, where you're feathering the throttle often and doing some weird things with the throttle in general. The 3d mapping allows you to stay safer.

When I used to tune for peak timing advance without a rescale, I would get the car to run great one day and then knock the next when the weather changed. With a rescale, it was able to be more consistent and adaptable to varying conditions and loads. But generally, it was harder to tune.

Also, the BIGGEST benefit of rescaling is more or less for those with larger than stock turbos and larger injectors. Hitting the peak load point assumes that you have rock solid boost control, and that you have absolutely no creep because essentially what you're doing is 2d mapping, richening the a/f based on only rpm. If you have boost creep for any reason or a spike, you're in deep kim chee. But, if you rescale beyond your highest load point, you can compensate for that freak situation that you overboost. It happens.

[GeorgeRex]

Thanks a lot, daemon and reid-o for your responses. I will put a little more effort into rescaling my maps.

[R4ND0M_AX3]

Originally Posted by GeorgeRex

I am wondering what is the real importance of rescaling COBB ST maps? If you hit a hypothetical load of 3.4 for example, does the ECU do a linear interpolation from the last load value such as 2.75?
Is the value of rescaling so that you can achieve greater control or non-linear value progression or both?

I am hitting load values of 3.52 on my standard ST maps which stop at 2.75 load and have not experienced any problems.

I have been trying to rescale maps posted by TMS but can't get Excel to do it right. When I use auto fill on a declining value row, the first value in the new column is higher than the last one in the existing column. e.g. 15,14,13,12,11,12,11... If someone could post a tutorial with screen shots, that would be awesome.

Cheers,
GR

if you run outside of the maps then the ECU just uses the value for the last cell. If the last load colum you had was 3 you would get the same values if you were actually running 3.1 or 3.5 or 4 etc.

I'd use a map that is a little higher than what you actually see.

I don't have an answer to your excel question. If you run into a pinch then just do it manually.

[TheMadScientist]

One way to rescale the maps.
Open your map in one ST window, open the map you want to rescale in a second ST window. Then just copy and paste from one window to the other.

I talked to cobb about rescaling. Cobb's reply was you can run up to 10% over your last load column. If you go higher than 10% over you should rescale the maps. Personnaly I don't like to run off the maps. Mostly it is just training from running a utec for so long.

TMS