Got a technical question for you guys that know more about these things than I do. I'm a long-time loyal Troyer fan, but due to certain emissions requirements, I had to switch to a local tuner a few years ago. Yes, I am just now getting to this question because I haven't paid the F-150 much attention for a while now.

(I recently inherited the GM version :o of my truck with LOW mileage, so I am trying to get it up to speed and preserved for my son to inherit one of these days. Looking at used 2815/2865/2950 tuners currently.)

Anyway, after dyno tuning my truck and making 10 runs + 4 on the street and getting Superchips involved to get my truck to go open-loop, I asked the tuner for 87 oct "tow safe", 91 oct "tow safe", and 91 oct "max perf" tunes. Since he is more of a car / track performance tuner and not an SUV tuner so to speak, I asked how he would accomplish this based only on the max performance tuning he had just created. He said all he had to do was pull timing for the tow safe tune, and pull even more for the 87 oct. tune. He never mentioned Air / Fuel ratios.

As soon as I got home I loaded the 91 oct. "Tow Safe" tune and have been running it ever since, or about 15k mi. Since I RARELY tow, and now have the Silverado to tow with, I am considering going back to the Max Perf. tune.

I'm just wondering if I might have lucked out since I haven't had to tow anything in the last two years, or if I should be able to trust the tow safe tunes based on the limited info I got about the changes? I did call and ask at the time for him to confirm the changes made, but at the time I didn't consider the A/F ratio specifically, just timing and EGT's.

Here is my old, pre-4.10's dyno graph if it helps at all. 5-speed, so runs were done in 3rd. rather than 4th to keep the tires where they belong. I also can't help but to wonder if there is more to be had. ALL sensors and maintenance items were FRESH at the time of tuning, in addition to full intake, gasket matched everything in the intake track, full exhaust including longtubes and Maggie cats, Troyer fans & pulleys, etc.

Have I mentioned how much I miss Troyer? If the truck were newer or had more duties, I would take the necessary steps to switch back, but it just doesn't see enough annual driving to even justify a mileage based oil change these days. :o

 

If there is a question in there, I'm having a bit of difficulty as to what it is. Your dyno shows a 13:1 air/fuel ratio which is a little leaner than what I'd want at WOT, but not lean enough to hurt anything. If the PCM is programmed for something richer, adaptive controls should take care of that over time. Usually when there is an issue between actual and commanded, the transfer function for the MAF is a little off.

Are you afraid that if the performance tune has the same A/F ratio, it will cause issues with a slight bump in timing? I don't think you have much to worry about, if that's the question. If there more power to be found. Probably, but it would be so infinitesimal, you wouldn't notice it.

 

Sorry for the rambling post.

The question is, if all that was done to the max perf tune was pulling a few deg. of timing, and nothing to A/F, would it be safe to tow with?

If not, and I don't tow anyway, I may as well run the max perf. tune. The dyno graph was with the max perf. tune.

I'm under the impression that A/F and thus EGT's are the issue with towing with max perf causing det. and exhaust valve pitting. I did tow a PWC once for about 100 mi. and I did have to have my exhaust valves faced. This was after running about 35k. mi. on Troyer's max perf. tuning.

Does timing have a direct impact on A/F ratio?

 

I don't think you really need a towing tune unless you're towing something in the range of 2,500 lbs. or more. A/F ratios are more likely to have an impact on timing. You can get away with a little more timing with a rich a/f ratio than a lean a/f ratio. If you start hearing spark knock or detonation with your max performance tune, then the timing is too much for the engine. I doubt the difference in the two tunes is more than a couple of degrees of spark advance.

 

I believe Troyer said a max perf. tune shouldn't haul more than max. payload of like 1,600 lb. in my case IIRC. Would a dyno tune be any different in this regard than a Troyer "mail-order" custom tune for an XCAL2?

My concern is that he didn't think to also compensate for A/F when creating the tow safe tunes because it didn't take him any time and he never mentioned A/F, even when I asked about EGT's. Especially since you and someone previously mentioning the leaner A/F I laid out above.

Not only due to exhaust valve pitting, but also because my long tubes come within 1/8" of the starter at one point. Luckily they are stainless and heat wrapped in the area.

 

I would go with the tuner's recommendation on his tune. When I think of a tune specific for towing it would be a heavier payload than that. I guess it depends where you live. There are no hills in Louisiana. I see you have quite a few modifications to your truck. If the tuner didn't spend any time dialing in the MAF transfer function, I'm not sure how good that tune is. Making sure your MAF reports accurate air flow to the engine is critical to the rest of the PCMs functions. You should probably do some data logging with that Xcal2 and see what's going on. You can log your short-term and long-term fuel trims as well as the timing and a/f ratios commanded by the PCM.

As far as the a/f ratio in that graph. I can tell you Ford does not program anything that lean in the stock calibration. Unless he leaned out WOT fuel commands, I think a lot of your mods are throwing the MAF calibration off. Most stock PCMs command about a 12:1 a/f ratio, give or take a few points in either direction. Hacking air boxes, putting bigger tubes or bends where they didn't previously exist in the intake tract can all throw the calibrations out of whack. If your truck was commanding 12:1 and delivering 13:1, that's not an acceptable error from a dyno tune in my book. A custom tune couldn't catch that same error unless you do some data logging, and unless you have a wideband in the mix, makes it very hard to determine where you are on the high end of the MAF curve.

Give me a little more information on your intake mods and where the MAF is and was located and whether it's stock, modified or aftermarket.

 

No, the max performance tune is factory recommended max. payload for hauling, not towing. Tow safe just compensates for the extra load by richening things up to lower EGT's, I believe.

He spent all day working on it and trying to get it to go open loop sooner. He also ran data logging on the street as well as dyno runs, but no wide-band in place on the street. Only thing I know I didn't like was that he wound it out so high.

Chopped factory airbox with K&N drop-in, stock MAF, ceramic coated WMS Velocity Tube, opened TB to a true 70mm from stock 67mm, also throated and gasket matched the TB elbow and upper intake manifold. I knife-edged the split section at the opening of the upper, and port matched each intake runner on upper & lower. Also blended on the injector shrouds some. I must have removed a pound of Al.

This is a well respected shop that usually sees exotics & high HP muscle rather than rice or pickups. Maybe I put too much into that.

 

To only travel 100 mi., I don't think it matters. I routinely pull a quad on a trailer with no trailer tune and I'm supercharged.

Where was the dyno run you posted in relation to the others? Do you know the sequence? If it was a early run, he could have made changes to the transfer function. The truck strategies are a bit different from the mustangs. If he had that much trouble just getting it to go open loop, I'm not sure you got your money's worth.

 

Not quite sure I know what you mean, but this was the last run of the day. A/F's were richer than that on other runs and it finally hit 13:1 there for him after he claimed to have gotten it figured out. I spent all day, 7 hours or so on the dyno. He didn't do anything but that day.

Not sure whether to get it re-tuned AGAIN or load the max perf tune and forget about towing.

 

Anyone else have any input?

 

13:1 is a little lean in my book... I like 12- 12.5 to 1 on WOT. I don't have any experience tuning fords yet but I can imagine when the egt's hit a certain point the engine computer dumps more fuel to cool things off, as mentioned earlier. As far as Your maf reading incorrectly... I highly doubt that a hole in the airbox or higher flowing airfilter would cause your maf to read incorrectly. Hot wire gets cooled by incoming air, the cooler the wire: the more air flow, all measured by resistance.
Timing advance should not affect your afr. To richen your afr you need to increase injector duty cycle or raise rail pressure.
When maxing out fuel system flow i've seen leaner than 13.8:1 wot on test runs, then had to dial everything back to safe levels... this is on a turbo car running 5 bar rail pressure 39 lb injectors.

 

Do the Mustangs command 13:1? Maybe he tuned it as a Stang rather than an F150...???

 

As far as tuning goes 12.5ish is the standard for most gasoline cars at wot... enough fuel to cool the engine under high load, and usually stated to produce the most power. 13:1 is not terrible and is still richer than 14.7:1 (stoich.) So there is still some decent cooling going on. What are you using to get your afr readings? If you are converting from narrowband voltage, you may not have correct numbers.

 

That was with wide-band up the dumped tailpipe with no restriction up to the brand-new Maggie spun-cats coming off new longtubes.

I have put about 20-25k miles on it like this, so I think I will just continue to run the "Tow Safe" tune I have been running all along. It has to be at least a little "safer" than the Max Perf. tune used on the graph'd run.

I am picking up a Superchips 2865 for my Silverado :x this afternoon, and I will probably run the 91 oct Tow Safe tune on it as well. I don't tow, but since I own a PWC and carry a tow strap, I may as well be ready just in case. No reason to have a Class 3 hitch otherwise. Thanks for the input, I will look at getting on the Dyno again with the F150 when money allows.

 

Going by what is in the OP's signature, he seems to have a different throttle body, air tube and elbow. A combination of these components and a freer flowing exhaust can alter the calibration of the MAF curve from the factory components. This is more prevalent on a 3v engines. If engine output is greater than stock, there's a chance he's exceeded the factory transfer function on the high end of air flow. Ford doesn't much care what happens if the volumetric efficiency of a stock MAF is exceeded on the higher end of airflow on a truck MAF. They tend to make some provision for it on mustang calibrations. A good tuner can reconfigure the transfer function to give more resolution on the higher side of airflow.

This is a pretty poor way to tune. If you're maxing out fuel injectors and MAF, the right way to do it is to get larger injectors and make sure the MAF and fuel pump can handle the airflow and provide enough fuel. I'm not trying to start an argument, but this sort of "tuning" is tantamount to fooling the PCM. The PCM is capable of making the required fuel metering decisions, but the components have to be up to the task.

I've never seen a base fuel table for any Ford product I've had access to written with less than 12.5. on high load fuel, and most are in the 12:1 range or richer. Granted there are all sorts of multipliers that can change the final result. If you want to see what your program is commanding, you need to data log. No one is going to give you any better advice on your current tune unless you can give them a log of what's going on in your tune. Same goes for what's actually happening and the only way to do that is with a wide band.