Just wondering how much difference I would notice between xcal's 87 and 92 octane for milage and towing? I will buying 1st a roush system and then a s&b/xcal at the same time if this makes any differance. I currently tow a 14' trailer everyday for work with my 04 screw 5.4 and I'm getting between 12/14mpgs and want some more.

 

I have an 87 and 91 tune from Troyer and here is what Ive noticed.

When it comes to milage, I really cant make a fair comparision because any time I have the 91 tune in Im WOT every time I can be it seems like. So Ive never figured the milage on 91. BUT, even with being on the gas all the time it seems like I can go just as many miles on 1/4, 1/2, 3/4 of a tank as I can with casual driving on an 87 tune. So, even without figuring out the milage, that leads me to believe I could actually get better milage if I drove civil with my 91 tune.

As for the performance difference. The first time I ran my 91 I didnt think I noticed a big difference. Finally a few weeks ago I ran 91 for about three tanks, then switched back to 87. I could definatley tell the different in performance then. It felt like a dog on 87 compared to the 91.

These are both performance tunes, so I cant tell you about towing with them...

 

if you are talking about a roush exhaust and a S&B intake with a custom tuned Xcal then get the 91 octane towing tune; you'll pull better and probably get better mileage doing it.

talk to your tuner: Mike @ Troyer and Justin @ VMP are both great tuners for xcal2's

add some efans, long tube headers and a set of lower gears, if your towing everyday swap to 4.10's or 4.56 depending on your tire size and you'll be much happier

 

91-93 octane is where it's at.

 

on 87 performance I get 15-16mpg with daily driving
on 93 performance I get 15-16mpg with daily driving
on 93 performance and running the crap out of it I get 15 mpg-and alot more performance
0n 87 towing it tows alot better, but I only get 14.5 mpg(rarely use it though)

 

Thanks guys, the only reason I am a little hesitant about the premium tune is the cost of fuel now a days. But if the performance and mileage is there then its a nobrainer.

Maybe Ill get both tunes and use both of them and see which is better for me.