cdynaco

Yeah I caught that...

Like I said before my stock Bullitt has adjusted great from sea level to 7000' - actually 7800... and that was no leisurely drive either. I got lucky on the last day of the year for the 'Rim Drive' around Crater Lake to be open... they already had the barricades up but let me sneak through since I had called ahead. So I had the entire Rim Dr to myself as my own private race course! LOL I drove it hard and there wasn't any indication that I was at high altitude.


(if you enlarge the pic you can see the 7865' altitude)



http://www.charliehorse.com/Bullitt-Crater%20Lake.htm

So thus far, it sounds like its the Brenspeed tunes that are struggling at altitude. What would confirm it is if someone having trouble would reload the stock tune and drive it to the same area.

oldlugs

B-speed tune on my otherwise stock Bullitt, just falls flat at altitudes over about 6K feet. It's so bad, I had to reload the stock tune, which works fine at altitude. I must say though, that the B-speed tune worked great at low altitude, especially when first loaded. Sucks at high altitude though. I've found that Bamachips tunes work pretty well at altitude. Seems something just not written right or corrected for in the B-speed tune, at least on my car. Your results may vary..

jlmounce

I'm not a tuning expert, but the factory tunes have a certain degree of adaptibility. Obviously they have to be able to work at all altitudes. Using MAF data and I'm not sure if there's MAP sensors or not, could give the car data it needs to operate properly at high altitudes.

I wonder if the Brenspeed tunes simply shut this down in favor of a table driven approach.

At 4500ft where I live my Brenspeed tune is flawless. No holes anywhere and good power from off idle. But you start getting close to 6000 ft and the power drop become noticeable.

Up in the mountains above 8000 ft the powerloss is so numbing as to make the car nearly undrivable.

cdynaco

If I remember correctly... the tuners do disable or limit the adaptability functions at higher rpm and WOT.

Don't know if this helps or not but I saved these notes from Brett @ BKU Motorsports from a pre-crash thread. I keep trying to grasp this tuning & A/F stuff:

First, an air filter would have to be so clogged to restrict enough air flow to throw a MIL you would have "SEVERE" drivability issues noticed, the MAFS to TPS variant is extreme on the EEC-V in open and closed loop, this would also start as a soft code and have to be repeated on consecutive drive cycles to trip the MIL, also if the ECU trips the MIL for improper signal voltage from the MAFS, it will default to open loop. Regarding WOT tables, just so everyone understands this, because most people do not, including Techs, yes I just said that!!! At WOT the ECU runs off from an OPEN LOOP strategy, not closed loop. Because of the Ford factory setting, the Adaptive Strategy Learning function on the EEC-V, with its ability to rewrite Open Loop WOT tables, is a risk to the engines own wellbeing (Basically it’s too smart for its own good) because of this most “good” tuners rework the adaptive learning table in the programming to prevent learned corrections from being applied under WOT, or disable Adaptive Learning all together. Since Colby is running a Brenspeed tune, his ECU would not have leaned his WOT tables, that would of have had to been done manually in the tune, I know Brenspeed reworked the adaptive learning table in his tune, they are a reputable tuner. Also, just for your own information, 3 degrees or even less is a common adjustment to correct for WOT detonation (Pinging). With the EEC-V many ECU parameters are logged in real time, including the STFT. Depending on the data-logging system being used, STFT can be reported differently, sometimes as a plus or negative percent (minus STFT meaning the engine is running lean, so the ECU is reducing its calculated A/F ratio in order to get the actual desired A/F ratio), or as a number around 1.00 (STFT numbers less than one, meaning the ECU is correcting a lean condition). As for Adaptive Strategy, if the ECU constantly needs to shorten calculated PW to achieve the desired 14.6 A/F ratio in CL mode, it knows its programming is calculating a PW too long (possibly from erroneous sensor inputs), and it will remember that correction for next time it makes a PW calculation for the same operating conditions of load and rpm. In other words, the ECU actually learns. The remembered corrections are known as Long Term Fuel Trims (LTFT). The LTFT work oppositely to the STFT, i.e., a plus LTFT (or LTFT greater than one) indicates the ECU is adding some to the calculated PW, in order to get the A/F it wants, based on what it's learned in the past. Even though the ECU only knows it's hitting the desired A/F ratio when the A/F ratio is stoichiometric (in CL mode), the ECU can also apply the learned corrections (LTFT) any time the ECU is operating in OL mode, and commanding an A/F ratio other than stoichiometric. Adaptive Strategy allows sensors to age and drift in their readings, but the ECU can now correct for the errors, and still hit the desired A/F ratio in the end. In the real world, adaptive strategy can be a problem. For the EEC-V, corrections learned at one set of operating conditions (e.g., idle) are also applied under other operating conditions (like high-rpm WOT). In that case, if you have a MAF sensor that reads too rich at idle (typical of many aftermarket MAF sensors), a leaned idle correction is learned, which if also applied at WOT, can spell disaster. It's necessary to either rework the adaptive learning table in the tuning to prevent learned corrections from being applied under other operating conditions like WOT or throttle chops, or make certain the MAF sensor calibration is corrected. The least desirable technique is to disable adaptive learning in the tune. This is why I always preach a good dyno tune is the only way to do things properly, that’s why we won’t sell anyone a tune unless they bring us the vehicle for dyno tuning!!!

jlmounce

That would seem logical for WOT or near WOT operation, but unfortunately we're talking about low speed driving. If I get some time I'll see about calling Brenspeed and see what they have to say on the issue.

It would suck to have to reinstall the stock airbox and tune every time I wanted to go into the mountains.

cdynaco

Oh... right... I forgot about that... can't just reload the stock tune because most tunes are adapted for mods.

jlmounce

RIght. The bullit you can because in general I don't think you guys change your intakes. Just the tuning. That makes it a 2 minute job before you take off. No worries.

For us non-bullit guys with intakes...it pretty much sucks.

Again though 90% of people purchasing tunes and intakes probably don't have wild elevation swings that their car operates under.

jlmounce

I just now read the long excerpt recovered from before the crash.

So it's possible then that the adaptive abilities of the EEC have simply been shut off completely. That could certainly account for issues when the car is driven up in altitude rapidly.

white08gt

What octane is your tune running? 85 octane is about you can get in Colorado, plus your axelback is causing a little loss in torque. When i put straight thru axelbacks on i lost a little down low. Before i put them on i could drive at 40 mph in 5th gear but after axelbacks it lugged in 5th and had to go 4th gear and i am sea level. I travel to Colorado quiet abit in fall to go elk hunting in the fall for the past 20 something years with trucks with carbs and efi, mainly had trouble with the carb running way rich so the octane tune will really make a difference with gas there. I would never run more than a 87 tune in high altitude. Stock mufflers will give you more back pressure for low end, just my experience.

jlmounce

The tune is for 91 octane. The richest swill we get in these parts.

Some loss of torque from a freeer flowing exhaust, and some power loss from altitude is to be expected. What I and a few others are talking about is a debilitating loss of power. Enough to cause the car to be nearly undrivable. Especially if loaded with passenger or traveling up a grade.

06StangSC

That's true too. Octane reduces at higher altitudes right? Hence 91 here and 93 elsewhere? Just call and get a spare tune imo

jlmounce

Octane does degrees with altitude, along with the need for knock resistance.

However the 91 we have in Colorado isn't simply 93 carried to higher altitude. it is a different formulation closer to what California uses.

It's looking like I'll have to get a new tune.

sycd

I have run my car with Brenspeed tune at sea level and 5000 ft and it feels like a complete different car. I had the same issues at high altitude as the folks already stated above. Severely reduced power under 3k rpm, and seemed to run richer from the soot around the tail pipes accumulated after just a few days.

Suntzu

has anyone with the Brenspeed tunes at altitude shown this thread to them? Or contacted them for help getting this sorted out?

I am almost ready to commit to a supercharger this spring and Brenspeed was my number 1 choice to get the kit from, and have them install probabley. However if their tunes can't handle large altitude changes, I will look for someone local.

Thanks.

oldlugs

They're aware of the issue; they have to be. My guess is that relatively few Mustang guys drive at over 5000 feet altitude, so they have relatively few complaints. When I complained, they sent me another tune... And it had the same issues. I had already switched to a Bama tune by that time, and it worked better for me. Right now, I'm running the stock tune. It does have some throttle lag, but gives slightly better gas mileage than the Bama tune, and sounds better on decel with my KR mufflers. I know that most people don't care about fuel economy with their 4.6L V8, but my Bullitt is my sleeper/cruiser. When I want more ZOOM, I take the KR...

jlmounce

Having a bullet would be nice for that specific reason. To do that I have to actually swap out the intake. Although not hard, it's not something I want to do every time I want to go into the mountains.

I've still been researching this a bit and contacting a few people is up this week for me.

Based on some of the things I've read, it may not be a bad tune per-se but how the tune is developed.

If the tune is based on the MAF X/fer funtion, it shouldn't matter where the car is because the MAF will provide the atmospheric information necessary to get the commanded air/fuel ratio regardless of weather or altitude.

If however this is bypassed for a table based operation, then you've only got proper operation at or near sea level where those tables are likely based.