johndeerefarmer

This afternoon I tested the TREX jr 87 octane heavy tow tune. I was running 93 octane.

I first ran it unloaded for awhile to get the truck used to the tune. On my unloaded test run I saw 21 mpg with a 15mph tail wind. On the return trip bucking the wind I saw 16.5mpg (these are at 60mph my usual speed for tests). Averaged together I come up with 18 3/4 mpg. I have run quite a few tow tunes from many different companies and this is the first tow tune that actually gave me fuel economy equal to (or maybe even better than) stock. I will have to do some more runs to get more accurate data but what I see so far looks very good. For those that don't know I have a King Ranch fully loaded CREW cab with 6.5' bed, bedliner, toolbox, gooseneck hitch and air bags. I weigh in at 6500 lbs. Couple that with 3.73 and fuel economy stinks, so if I can get 18 -19mpg at 60mph I am as happy as a pig after a slop bucket. Since I tow nearly every week I need my tow tune to be my daily driver so fuel economy matters to me.
Running unloaded I observed:
knock maxed out at 3. At WOT was 1.8. This tune has lower knock than any other tune that I have ran. My others have been from +5 to +10.
Max boost observed was 19.5 psi
Low end doesn't feel like a tow tune, feels like a performance tune- more on that in a second.

Towing. Today I towed my 6k lb gooseneck. I ran my usual 30 mile test run which includes multiple 1-2 degree rolling hills.
It has so much low end power that my tires would spin at each stop sign or yield sign on the way to my "test track". Shawn is tweaking this a little for me- I don't want to throw my cows down or my dishes out of the RV.
Boost max was 19psi
Knock ranged from -2.77 to +2.99. At WOT was 2.5
I saw an A/F R of 10.8 at WOT. I like it rich for the safety factor as I tend to overload and overwork my truck.
Cat temps are better than T4 or any other tune that I have run. I would say that this tune runs 150 degrees cooler than my others. At 60 mph on level ground I was observing cat temps of 1550 degrees. At the top of the 2 degree hills I was at 1650 degrees. Cat temp max observed was 1728 degrees.
A/F ratio stayed around 14.5 to 15 with cruise set on 60mph
The only thing better than the low cat temps was the fuel economy. I observed 9.7mpg on this towing experiment. 5 star got 8.7 mpg on the same run, T4 got 8.2mpg.

Shawn is making a few tweaks for me and tomorrow I will be out for more test runs. First a few calves to the sale barn then I will come home and load up enough hay to have 10k lbs then go back and rerun my tests. I will report back again tomorrow evening if the rain and storms don't stop my tests. If so I will complete them on Friday

aliass24

Nice review, doesn't your knock seem alittle high for an 87 tune running 93?

johndeerefarmer

I am not a tuning expert nor claim to be, but I have run tow tunes from nearly every tuner out there. I have datalogged all of them and they all show knock of 2-3 under WOT while towing.

jwanck11

Good review. More tweaking to do, but this one is getting close(r). I am curious to see how everything looks when you really load her up!!

SkiSmuggs

Actually, a good tune adjusts for the octane that it sees. If it didn't, you would never realize the performance benefits of higher octane fuel. A tune that always remains at 0 knock is just not trying. On the other hand, a tune that consistently runs at +5 and above is not properly adjusting for conditions, at least that is what I gather from my reading here. And I mean under load for KR. Even the stock tune advances timing at cruise to improve the MPG.

Joewee3.5

It has been noted before that the tuner can set the range of knock that's detected. I think MPT said this and that they set that range higher for safety. I'm not a tuner do I don't know but if that range is set to max read 3 but it's actually knocking 10 that would be a problem. Nice review though. Sounds like a strong tune.

aliass24

So Ski, a tune showing 0 knock and negative knock isn't making max power? I thought running higher octane with a lower tune produced max power with a better safety window?

SkiSmuggs

It does, but I understand your confusion. Technically, the stock or an 87 tune should run just fine on 87 gas, but there can be extenuating circumstances such as running hard (racing, repeated WOT runs, towing, towing up a mountain) that can create heat that the tune with 87 gas can no longer effectively deal with. Think about what the Ford owner manual says about using premium fuel for towing or summer operation. You have a high performance engine that is designed to run on premium fuel, but modified to allow operation at a lower level because a lot of folks won't buy a truck that can't use regular gas. Regular gas just doesn't have enough anti-knock properties to prevent detonation under extreme conditions.
BTW, I have had other tuners tell me we should use premium fuel even with 87 tunes because it is safer and because you get about 20 more HP and 10 ft/lbs of torque even stock. No one has had more problem with this than I have because the penalty for premium is often .50 to .60/gallon here in Vermont.

EcoPowerParts

I don't want to see ANY knock and I saw no knock with my 600HP setup on E85. I don't agree with your philosophy of seeing some knock.

SkiSmuggs

Even the stock tune shows some knock so it must be Ford's philosophy. When it is zero, shouldn't a small timing advance occur to see if there is room for more?