i did use 87 but just switched back. how am i detuning when im am changing shifts points and stuff...

 

detuning your engine, not your shift points. but it seems others have had luck like you have had and seem to like 87 with 89. maybe there is something there i'm not understanding/don't know.

 

If you read threads on this on the SC forum, guys swear they get better mileage and performance with this setup. Not the performance of the Perf. Tune, but better performance than with the 87/87 setup.
The engineers and calibration team has even shown data where this is NOT possible, yet people still swear by it!
Personally, I don't know, but I only use the 91 tune (until they come out with a 93 tune) so I don't really care...

 

I think I get it now

 

The thing with the 87/87 or 87/89 is that it feels like it has alot more in the low end, and if you go by the "seat-of-your-pants" dyno, the truck feels like it is just ripping off the line which makes it really fun for in town/city driving. The reality of it though is that it works great for that 0-40(ish) sprint but anything in the higher speeds just doesnt feel that great with that tune in my opinion. The 91 tune has the better performance throughout the rpm range and feels much smoother. Again this is just how the tunes felt to me when I gave them each a try.

 

OK, I finally tried the XS tune today on a highway ride to Wilmington this afternoon. My plan was to run down and back with the XS tune and see how it performs. I am not really interested in getting better mileage, I just needed to do it to satisfy my own curiousity about this tune. Well, on the way down I got the same exact mileage as I got last time I made this same trip about 2 weeks ago. The only difference was that the truck felt like it had a lot less ***** than it normally does on the 91 tune. I didn't even test it on the way back. Once I got there I went back to the 91 tune and will not be changing it again until the 93 tune. At least now I know for certain what the XS tune does (or doesn't do) for my truck.

 

so you're showing the same thing I'm showing...not a damn thing.

 

Exactly. I got no gain in mileage by installing the XS tune and obviously lost performance as compared to the 91 tune. Not that I really care bc I am not that worried about the mileage that I get but I had thought there would have to be some gain by installing a mileage tune. Guess not. Just one more reason for me to stick with the 91 tune.

 

I keep mine on performance tune all the time and run 91 octane.

 

So far I have only had mine on the 87 tune and havent noticed any gain because my foot has gottin alot heavier. I will run a tank of 91 soon and change over to that tune to see what its like. The MDS delete option is going to be used right away too.