What's changed in an aftermarket "stock" tune?

[Dinosgt]

I can't seem to get a clear answer on this one. For folks that get a "tune only" on their GT500, what is changed in the tune?

Since Ford has to design the car for an incredibly wide range of use, I presume some compromises are made in the tune. For example, my data logs show the factory tunes around 9.7-10.3 AFRs under boost, and throttle openings in the 60-70% range. I presume much of this is to combat detonation, and to ensure clutch protection.

Most importantly, what do you "give up" in an aftermarket stock tune? Knock protection, safe AFRs, clutch protection, etc.?

I know a lot of folks rant about the improved drivability and responsiveness in the Lund, VMP, etc tunes, so I am curious what is modified vs the trade offs/downsides.

Thanks for for any insight anyone can provide.

 

[Imatk]

With an aftermarket tune you're basically getting a more aggressive tune.

The word "safe" is thrown around A LOT.

But the definition of "safe" is different for everyone.

A vendor (no matter who I suspect) will tell you their tune is "safe."

And of course they wouldn't want you to load one of their tunes and blow up your motor because then you'd be on the internet and on them because of it.

So like you suspected, there are trade-offs.

As far as improved driveability I've never noticed that with any aftermarket tune I've run.

More power? Yes... better driveability no... in some cases driveability was worse until the tune was worked out... but I've never had it be "better."

In the simplest terms what you're getting with an aftermarket tune is more aggressive timing and possibly turning off various features that will retard timing (like you suspected to prevent detonation).

For instance... some tuners will turn of COT in the tune. Which is a catalytic converter protective measure that basically dumps fuel into the engine to cool off the cats if they get too hot.

You lose power, but you have longer cat life.

That's just one example... there are many others.

And for one final thought.

If a tuner says XXX tune is "safe" ask them if they will warranty your engine and have them put that in writing. It'll probably never happen BTW... which shows you maybe just how "safe" a tune is

I'm not looking to scare you off BTW... just trying to be realistic with you. Lund, VMP I can personally say I've received excellent service from both. And so have many others... just know what you're getting when you get it

 

[VNMOUS1]

On a performance custom calibration for a 13-14 GT500, there are a lot of knobs being turned. But the basics are... depending on your location and fuel... Spark advance, base fueling calculations, adjusting some of the parameters that pull timing at x downstream temps, etc. We program for 11.1-11.5:1 on a Trinity.

We do not do anything with cat overtemp protection on catalyst controlled vehicles nor do we shut off nor bypass any factory failsafes.

We use every tool Ford gives you (us) to protect and optimize.

 

[Dinosgt]

With an aftermarket tune you're basically getting a more aggressive tune.

The word "safe" is thrown around A LOT.

But the definition of "safe" is different for everyone.

I'm not looking to scare you off BTW... just trying to be realistic with you. Lund, VMP I can personally say I've received excellent service from both. And so have many others... just know what you're getting when you get it

On a performance custom calibration for a 13-14 GT500, there are a lot of knobs being turned. But the basics are... depending on your location and fuel... Spark advance, base fueling calculations, adjusting some of the parameters that pull timing at x downstream temps, etc. We program for 11.1-11.5:1 on a Trinity.

We do not do anything with cat overtemp protection on catalyst controlled vehicles nor do we shut off nor bypass any factory failsafes.

We use every tool Ford gives you (us) to protect and optimize.

Thanks to to you both for the replies.

I appreciate the real world experience on driveability lmatk. Also, I wouldn't expect to get any guarantees on safety, but I also don't want a tune that squeaks every last drop of power out when conditions are ideal, vs one that accounts for real world driving conditions ( high heat, variable fuel quality at your local pump, etc.)

BJ - many thanks for the reply from a guy who has tuned more cars than most of us can imagine. I don't want the secret sauce in this thread, as I understand your hard work, as well as other reputable tuners is at stake, but I am just trying to get some basic understanding of what I am "giving up", in a tune.

For example, a very reputable tuner told me that Fords PCM wil only pull a max of 1 degree timing when knock is detected, but other lookup tables are used for additional timing considerations if needed (IAT2 for example)

Forgive my ignorance, but if we go to a more agressive spark curve with a leaner mixture, will the knock retard function be relevant anymore? I know it will still " work", but if we added in some more aggressive timing, and its limited to pulling only 1 degree, it seems that we have essentially negated its function.

Also, I have heard that Ford agressively starts pulling timing at IAT2 over about 130 or so. If we change that as well, same concern?

I am presuming most tunes turn on the intercooler pumps sooner than Fords which I think is at around 110 or so (from my data logging this seems to be the spot).

Finally, I noted that I only see about 65-70 throttle on my datalogs. I presume that this due to some type of clutch protection of torque limited function? (BTW this with the trac OFF). If we tune that out as well, and go with commanded WOT at 82% across the board, what do I "lose" in that change? Will I toast the clutch in short order for example?

Again, many thanks for the insight.:beer:

 

[HighTorque]

Sub

 

[SRTchris]

What are you guys liking better.
Ngauge or SCT ?

 

[VNMOUS1]

Dinosgt, the knock sensor limit statement is incorrect. We can command the amount it pulls, the sensitivity, the rate in which pulls as well as how it recovers. As a rule, it will pull quicker than it adds back. So, it's important to have the calibration spot on and not pull any at all. The Spark Adder For A/F @wot will add x amount of timing if everything is in good shape. It's far more efficient and provides better power to command a little less timing in the table and let it add than to have the net result of rapidly pulling then slowly adding back. The KS adding and Spark Adder for A/F@wot are two different things btw.

Downstream temps. Ford stock cal pulls at 110f and scales more aggressively moving upward in the table.

IAT2 averages 30f above ambient so on an 80 degree day you can be pulling timing while idling in your driveway. This is why a fanned heat exchanger like our Triple Pass Dual Fan unit is SO important. When you have one, we raise that threshold in your cal to start later but act more aggressively at higher temps. Not only does it reject heat but the recovery time is monumentally faster.

Throttle angle. Yes, it's 82* at wot. Log both commanded and actual and compare them.

It could be shutting due to torque limits, clutch protection or a couple of other things.

At the risk of sounding like a pitch, this closure isn't something you have to deal with any longer if we tune your car.

Feel free to contact me directly at [email protected] if I can assist you further.

 

[Vegasgold]

I have the VMP stage 4 package and could not be happier. No issues, accelerates extremely fast. The whine on the supercharge is loud and you can still hear it with the off road H pipe. Best performance parts I ever purchased. I know there are other vendors with similar results. I am happy with my decision. You cant go wrong with the vendors here.

 

[1 Alibi 2]

As far as improved driveability I've never noticed that with any aftermarket tune I've run.
.
More power? Yes... better driveability no... in some cases driveability was worse until the tune was worked out... but I've never had it be "better."

.
I would have to disagree, the only thing that didn't get better, was gas mileage !!

 

[Bad Company]

BJ

I've heard of a tuner manipulating a table or percentage of commanded throttle angles versus the percentage of driver introduced throttle pedal movements to give the feeling of more Hp. Yet at the same time this causes the throttle pedal to be excessively jumpy at low load cruise conditions with jumpy transitions of the car as the driver is manipulating the throttle pedal lightly.

Could you explain this a little more?

 

[Catmonkey]

I think the better drivability comment has to do with aftermarket mods. The goal for me is making all my mods drive like stock until I plant my foot. A few aftermarket mods can make the car difficult to drive if the tune is not right. I've also driven some tunes where you use the first 1/4 throttle and then your WOT. Some may like that, I don't are for it. To me a custom tune is coming away from the experience with the car behaving like you want it to, not the way the tuner thinks it's supposed to be, so take it or leave it.

 

[Imatk]

.
I would have to disagree, the only thing that didn't get better, was gas mileage !!

How exactly did the driveability get better for you?

For me I want the car to drive exactly the same as it would on a stock tune until I put my foot in it. Maybe for some that's not what they want I guess.

I've run aftermarket tunes from reputable tuners here that had various issues until they were worked out.

Surging at idle, dipping at idle, inability to maintain idle while coasting etc.

 

[Imatk]

I think the better drivability comment has to do with aftermarket mods. The goal for me is making all my mods drive like stock until I plant my foot. A few aftermarket mods can make the car difficult to drive if the tune is not right. I've also driven some tunes where you use the first 1/4 throttle and then your WOT. Some may like that, I don't are for it. To me a custom tune is coming away from the experience with the car behaving like you want it to, not the way the tuner thinks it's supposed to be, so take it or leave it.

Agreed.

 

[HighTorque]

dinosgt, the knock sensor limit statement is incorrect. We can command the amount it pulls, the sensitivity, the rate in which pulls as well as how it recovers. As a rule, it will pull quicker than it adds back. So, it's important to have the calibration spot on and not pull any at all. The spark adder for a/f @wot will add x amount of timing if everything is in good shape. It's far more efficient and provides better power to command a little less timing in the table and let it add than to have the net result of rapidly pulling then slowly adding back. The ks adding and spark adder for a/f@wot are two different things btw.

Downstream temps. Ford stock cal pulls at 110f and scales more aggressively moving upward in the table.

Iat2 averages 30f above ambient so on an 80 degree day you can be pulling timing while idling in your driveway. This is why a fanned heat exchanger like our triple pass dual fan unit is so important. When you have one, we raise that threshold in your cal to start later but act more aggressively at higher temps. Not only does it reject heat but the recovery time is monumentally faster.

Throttle angle. Yes, it's 82* at wot. Log both commanded and actual and compare them.

It could be shutting due to torque limits, clutch protection or a couple of other things.

At the risk of sounding like a pitch, this closure isn't something you have to deal with any longer if we tune your car.

Feel free to contact me directly at [email protected] if i can assist you further.

do you use sct or hp tuners for ngauge?

 

[VNMOUS1]

do you use sct or hp tuners for ngauge?

hpt

 

[VNMOUS1]

BJ

I've heard of a tuner manipulating a table or percentage of commanded throttle angles versus the percentage of driver introduced throttle pedal movements to give the feeling of more Hp. Yet at the same time this causes the throttle pedal to be excessively jumpy at low load cruise conditions with jumpy transitions of the car as the driver is manipulating the throttle pedal lightly.

Could you explain this a little more?

I'm guessing it's neither, but perhaps increasing driver demand in the cal. Think rheostat on a kitchen light. X amount of movement = x amount of light. Now, imagine the ability to change the scale on which that occurs. If 10% movement= 10% light and suddenly you can get 15% light with 10% movement....well, that's the idea.

bj