Truth about tuners

[CaFordDude]

For post number 500 I thought I would start thread to see if we can't get to the bottom of this whole tuner issue. Good tuners, good companies, Bad tuners, Bad companies, detectable, not detectable. Is there such a thing as responsible tuner use. What mods are musts with tuners. How does a tuner work exactly. I know what the MM Act is but real world what happens?

Since I don't have a tuner on my truck (Have given it some thought tho) I guess this will all just be my opinion.

Do I think tuners are detectable? Yes and no. I do believe that a tune can be completly wiped from the onboard computer but I think there are probably other signs that will lead to a good tech being pretty confident a tuner has been used.

I do believe there can be responsible tuner usage for improved power for towing, maybe MPG etc. I do not believe that lighting the tires up once in a blue moon is any worse then doing it in an untuned vehicle.

I know a tuner modifies the trucks programming but WHAT does it modify?

I'm not trying to start any wars here, and this isn't really that kind of crowd but lets try and look at this issue as objectively as possible.

Just looking for some facts and honest opinions.

 

[Brian_B]

I don't know the anwers.

I have an SCT tuner for my explorer. Doug at bamma chips programmed it for me.

Unfortunately, when gas prices shot up, I stopped using it. I need to play with the 87 octane tune and see what it does.

I can't afford 93 octane for as many miles as I drive now.

 

[04Xcursion]

I guess the first question I have is: Is this a gas or diesel topic?

I think the realms are significantly different enough to warrant a distinction.

I'm going to stay away from the gas side of the equation because I just don't know enough about it. For the diesel side of the equation I can go on for an awfully long time.... But before I do that I want to make sure I'm not hijacking the thread

 

[CaFordDude]

I guess the first question I have is: Is this a gas or diesel topic?

Well you got me on that one as I did not know there was a significant difference. I have a diesel truck so feel free to spout away on the diesel side.

Since you did note a difference maybe when people make a post on this topic put "Diesel" or "Gas" in the title box.

 

[04Xcursion]

Diesel!!!!!!

Alright... This may be a little long winded but bear with me.

There are essentially 2 separate families on diesel performance electronics they are inline chips (Edge, Banks, Bullydog etc) and full blown tuners, within the tuner class there are 2 distinctions preloaded (Predator) and custom (SCT).

In order to understand how these devices create power I will go through some basic engine principles. If this is too basic I apologize but I don't really know the knowledge level of my audience.

First, do not confuse compression test figures with pressure test figures.

Compression testing only gives an indication of the status of the combustion chamber in an engine. It verifies that the piston rings are sealing, the cylinder isn't destroyed; there isn't a hole in the piston; the valves are still there, etc etc. The maximum value observable by the gauge is determined by the compression ratio of the engine. (P1V1=P2V2; assuming an ideal gas)

Pressure testing refers to taking in cylinder pressure readings which the engine is running under load. The readings here are affected by the mechanics but are primarily a result of fuel delivery, and to a lesser extent boost. As you can imagine these numbers are much larger than the compression test because of the effects of fuel exploding inside the cylinder.

Now as to the effects of injection timing and how chips make power with it.

The inline chips function, as their name implies, in line with the PCM. They essentially lie or modify data output streams to effect changes to fuel timing and fuel delivery. They have a couple of major drawbacks; the biggest one commonly experienced is that the transmission (for those with autos) does not respond properly to the new power levels, slippage and transmission damage have been commonly observed. Second, because they have a limited number of variables they can effect from the PCM they have only a couple of techniques by which they can increase power, basically increased timing and increased fuel delivery. These two techniques often result in exceedingly high cylinder pressures which can lead to (and often have) blown head gaskets.


Now by making the PCM delivery the fuel charge earlier, the fuel enters the cylinder further before TDC. Now when the fuel enters the cylinder it starts to burn, which is effectively increasing the amount of "air" in the cylinder. Now as the amount of "air" increases rapidly so does the pressure, bear in mind that while this is happening the piston is still moving upward, reducing the available volume for the combustion gases. This is a recipe for rapid pressure spikes.

Diesel engine always run with some degree of advanced timing because it takes time to burn the fuel, and for maximum efficiency you want the expanding gases to push down on the piston for as long as possible.

The problem with chip is that they usually play with timing and volume of fuel delivered into the cylinder, not the duration of delivery. So imagine this scenario: fuel is injected earlier and more fuel is injected; does this sound like and equation that will increase cylinder pressures to dangerous levels? You bet.... The more you increase timing and fuel volume the higher your cylinder pressures get. To add even more fuel to the fire so to speak chips usually allow for much higher boost levels. Higher boost levels = higher pressure at BDC of the intake stroke = higher pressure at TDC; ends up making the pressure increases from timing/fuel delivery combination that much higher. As you can see this is why headgaskets and studs are at risk. This also results in higher EGTs

High combustion pressures = higher power output because you have more pressure on the piston = more force to the crankshaft.

The custom tuners completely rewrite the PCM program and remap a host of variables to accomplish their tuning. I will limit my discussion here to the SCT XCalII product because I have a fairly clear understanding of how it functions.

Power in a diesel engine is derived from the mean effective pressure (mep) during the power stroke. Which means the average pressure over the entire stroke, not necessarily the peak pressure, although by definition high peak pressures do increase the mep.

What the SCT allows is the entire PCM strategy to be rewritten. Which means that all the parameters that affect power can be completely altered. A critical parameter which chips do not affect is the fuel delivery time. What this allows is an increase in power by increasing the mep. If you continue to deliver fuel while the piston is traveling downwards you extend the burn time, and maintain a high cylinder pressure longer but not creating the massive pressure spike which occurs with lots of timing advance. This results in higher mep but lower peak pressures.

Also there is a tremendous flexibility dealing with timing/fueling/boost. The relationships between these parameters can get quite convoluted to explain, but with the proper combination you can derive much higher power with the same or lower peak cylinder pressures.

In addition to the control of the combustion process SCT tuners also have the capability of full TCM control; which allows full control over shift points, shift scheduling, line pressure, torque converter lockup and all the other various parameters involved in the coordination between the transmission and the engine. This is what allows custom tuners the ability to extract substantially more power from the engine without causing the failures which have been so prevalent among the in-line chips. Eventually there are mechanical limits to what can be achieved and things break but the window is much larger with programmable tuners such as the SCT.

Also bear in mind that custom tunes are only as good as the guy writing them; they can be anywhere from amazing to undriveable. Chose your tuner wisely and be prepared to work with them to get your tunes exactly the way you want them (yet another advantage of this kind of product).

Now I have failed to address the preloaded tuner class, they are somewhere in between inline chips and the fully custom tuners; they have the ability to control many of the variables but fail to address the individual consumers; everyone drives differently; has different levels of modifications; expects different things from their vehicles. So in an effort to appease everyone they often use shortcuts and compromises to get to the ends they want. I know the early versions of the Predator used a ton of timing advance and rapid fuel delivery to get good power and awesome mileage but the result was many blown head gaskets.

OK..... There's my novel for the evening,I think I've beaten it to death I hope it has provided some explanation as to how chips/tuners work. If I have been unclear please do not hesitate to question me; I will try to explain in more detail if requested.

My personal poison of choice is the SCT XCalII with tunes from Spartan Diesel.

Thanks for your indulgence

Jason

 

[6L PWR]

Another DIESEL post

Eventually there are mechanical limits to what can be achieved and things break but the window is much larger with programmable tuners such as the SCT.

My block has a window in it.

Hopefully, ya'll that are interested in souping up a 6.0L Diesel have read my thread on my THEORY of why my 6.0L blew up. It was NOT the tuners fault. I still believe in using a tuner like the SCT xCall 2 as Jason does. If you're going to change the programming, you have to change it all. Also, you have to change the programming, NOT fake out the sensors to change variables as an in-line chip does.

 

[bowtiehatr]

diesel and gas

very good point todd. the ones that "lie" to the pcm, usually change tempertures and load percentages to outrageous number and the inlines also will not allow me to reprogram the pcm due to blocking the programming line. also i have seen random codes pop up due to these "lies" which was only the add on module/harness which i enjoyed those customer pay times. also on 7.3 diesels with the plug in chips, i have seen several no starts or corrupted tranny strategies due to lose improper seated chips in the back of the pcm.

on gas, i have seen some strange stuff being caused by chips. on lightnings i have seen the pats system be disabled causing a no start, to ebing hooked up to a car with a tune or chip and the wds would recognize it as completely different vehicle instaed of what was there.

all in all, it is just a computer and software. sooner or later there will be issues to some degree. whenever someone calls me over funky codes in a tuned truck, or a stupid acting truck, first thing i tell them is remove the tuner and see if that fixes the issue. so many things can happen if the software gets a glitch in it somwhere.

 

[CaFordDude]

If this is too basic I apologize but I don't really know the knowledge level of my audience.

Too basic? Shoot this is the last sentence I fully understood. Good write.

 

[Bob Ayers]

Higher boost levels = higher pressure at BDC of the intake stroke = higher pressure at TDC; ends up making the pressure increases from timing/fuel delivery combination that much higher. As you can see this is why headgaskets and studs are at risk. This also results in higher EGTs

Good write up.....one small correction, intake should be compression.

 

[04Xcursion]

Good write up.....one small correction, intake should be compression.

Thank you sir; I was thinking BDC intake stroke, TDC compression stoke and didn't say it

 

[O'Rattlecan]

informative, 04Xcursion. Thanks!

Ryan

 

[mrxlh]

Aaron, I will dumb it up for you. No a tuner cannot be traced on a 6.0 if certain steps are taken. Yes good techs can speculate or guess that they were used, but only if you admit it. Next, for your specific truck, the Xcal II is the top performer and is about as safe as it gets, depending on who tunes it and what you tell them you want. No a tuner is no more dangerous for your truck than if the VGT sticks and overboosts to 40 psi towing a 12k load up the grapevine. Pros and cons to be made by insuing people I am sure, some far more educated than me. When your ready to play, be willing to pay up front, and you will have zero issues. $2500 and a little help from friends and you'll have more fun than is probably legal in CA, oh wait your a cop, scratch that.

 

[mrxlh]

Well now that Matt is here, any specifics, give him a shout, as he knows way more about them that I do.

 

[JohnBoyToo]

Deezle too

Good tuners, good companies, Bad tuners, Bad companies, detectable, not detectable. Is there such a thing as responsible tuner use. What mods are musts with tuners.

Think you got the "How does it work?" answered
Since we started at the last question, I'll try the next previous

Musts Mods ?

Some say gauges, but I say
ANYTHING other than stock exhausts !!!

gauges will tell you when it gets too hot....
better flowing exhausts will stop it from getting too hot in 99% of the situations

The best is a good mandrel bend full turbo back exhausts (what I did on the 03 Ex),
next is a good mandrel bend cat back exhaust,
and then it gets into opinion...

some say remove the muffler and cat - I won't do that for a few reasons...
(LOUD and $10k federal fine if your are caught

what I did on the 05 Ex was a Walker BTM (Big Truck Muffler) - inexpensive - lifetime warranty - good mellow sound - lowered egt's in the 250 degree range.


Now that you have the output taken care of.... what about the intake since an engine is JUST a big air pump
Some go aftermarket, but I've decided the stock one flows VERY well, filters the best, and last a LONG time...
(DO NOT USE A K&N on a turbo charged deezle !)


Responsible?
Mine is a race tune on an everyday driver....
if you don't use the race portion of it, it's still better than stock !

the perfect tune to me though is:
max hp & torque AND mpg
short shifts when not racing.... (both quick/firm and low rpms - it WILL go 70 mph @ 2K rpms )
get into highest gear when running around in town with traffic going a steady state 40 mph...
(don't need to be in third !)
locked torque converter in 2nd thru 5th

 

[blacksnapon]

So far, looking at them from a dealer tech standpoint (are you ready?) Matt is the only one I have seen putting in concerns for engine/trans longevity. All the others have been "Damn the consequences, more HP!", and "Take it off, they'll never know!". When all the efforts are concentrated on only those two, I cant see them doing much for customer satisfaction, and long term happiness.

 

[mrxlh]

Vince, that is the reason why he has the customer base he enjoys. You and I both know that certain parameters of Fords calibrations are detrimental to survival of the entire package. I don't and will not ever expect you publicly agree to that. If you tell Matt where you stand (financial, warranty, ect) he will not steer you wrong. I begged him to go the direction that he is now pursuing with his tuning. So far it is proving a correct guess.

 

[Brian_B]

I guess the first question I have is: Is this a gas or diesel topic?

I think the realms are significantly different enough to warrant a distinction.

I'm going to stay away from the gas side of the equation because I just don't know enough about it. For the diesel side of the equation I can go on for an awfully long time.... But before I do that I want to make sure I'm not hijacking the thread

After he asked that question...I stepped out of this one. I know nothing about diesel engines or their tuning.

 

[blacksnapon]

There are some things that can be thought of as "questionable". When they are attempting to balance emissions, fuel economy, longevity, suppliers wants and needs, some decisions can raise more questions than answers. In this world of contracts, I think the package they provide is the best they can offer, under all circumstances. My stand is to work with whatever I am given, with as little bloodletting as I can. I often do sit back and admire some peoples work (sometimes looking to see if it is adopted by Ford later). The pulling of cabs to facilitate engine work is an example. At first, it wasn't sanctioned by Ford either.

 

[mrxlh]

Good point Vince on the cabs. Some of the aftermarket tuning has made it into the ECM.

 

[captchas]

didn't read the whole thread guys.but in my shop i have found that the good ones are from sct and diablo. bully dog and edge are giving me supper head aches with thier over twisting of the motors anad tranies.

right now i have a blown 6.4 with melted pistons and a dodge we can't keep a trans behind for more then a week. the dodge has a edge. this last time every peice of the trans and converter was broken apart and converter wise i'm talking a presision unit one of the best made and only after the kid reinstalled the edge tuner.

with our custom sct tune we don't have any problem. any ideas what to do next guys? and yes i have called edge and bully dog they say no problems in thier testing