The following was copied from another car club. I am not the one who wrote it.
12-10-2006, 02:55 AM
RWTD
Junior Member Join Date: Dec 2006
Posts: 3
First off, please let me state that I am not here to create and rift or issues. I'm only here to clarify any incorrect information, and I will do it with tact and professionalism.
Quote:
Originally Posted by MikesMerc
The issue being discussed here is whether the Trilogy kit is inherently flawed because the IAT is at the MAF. Most of us contend that the answer is no.
In my professional opinion, I would state that is a flaw in the system. Futhermore, there is another inherent design flaw in the Marauder kit, and that being only one port that actually sees boost, and it's only used for a boost gauge. Therefore, the FRPS (fuel rail pressure sensor) does not reference boost, and it only sees intake vacuum (never boost). This isn't so much of an issue if the car is tuned for a specific boost level, but once boost is raised then it must ALWAYS be retuned, otherewise it'll lean out, regardless that it has a MAF sensor.
With proper FRPS boost referencing, and a properly tuned MAF curve, one would not have to have their vehicle returned for small changes in boost (generally changes of 2 to 6 psi either way). This also only applies if the spark table has been properly tuned, in both the spark values inputted, and also proper Load axis scaling, otherwise the pcm will continue to use the same spark values when increasing the boost, and that's not a good thing at all.
This is not a bash on Trilogy, but rather simple facts. I would hope that they would use information that myself and other prominent professional tuners give them to improve their kit even further, because it is a nice system with a LOT of potential and promise.
Quote:
Originally Posted by MikesMerc
Powersurge already posted the fact that the OEM cobras also have there IAT sensors in the intake tube. The IAT2 (which is after the blower) doesn't do squat to the timing or tune.
Let me stress that the information you were given is 100% incorrect!
The IAT2 on a Lightning and on a Cobra, and on ANY supercharged Ford that has two IAT sensors, is specifically used to add/retard spark based on post-blower temps. This is fact. From the factory, when post-blower temps exceed 100 degrees F on either a Lightning or a Cobra, the pcm will use a multiplier, based from two different parameters, to determine how much spark to retard. The higher the post-blower temps get, the more spark is retarded. If one has done much datalogging on a Cobra and a Lightning, they will find that even with the very efficient intercoolers the IAT2 will generally always be above 100 degrees, regardless of outside weather. From the factory, Ford's programming is already retarding spark based on IAT2! I'm more than happy to post up screenshots of various parameters so that I can help to properly educate everyone to cause and effect. Please just let me know if you would like such.
So everyone will know, I study IAT temps *extensively*. It is something I do not only for work, and I do it daily, but also for fun. One of my product lines for intercooled vehicles is also heavily involved in this regard.
Quote:
A much better approach to tuning is to assume the intercooler is working as designed and then dictate exactly what you want to happen in the tune. Powersurge commented on this as well and I fully agree. So does Lidio. We spoke on this matter. "Adaptive" tuning is NOT the way you want to go with a high horsepower car.
"Assuming" is never smart when it comes to tuning. Using actual data supplied correctly is. Adaptive spark correction, due to changes in conditions, is 100% proper and correct.
Quote:
The reality of "well, what if my inter cooler stops working" is a silly reason to go through the time and energy to re locate the IAT sensor. I suppose I could have a sensor on my bumper that will warn me if my bumper falls off too...but is it really what I need?
I just do not understand the logic of comparing a bumper falling off to something as important as proper placement of an IAT sensor? If you go by that, then just take off the IAT sensor altogether. Who needs it, right?
There has been many Ford supercharged vehicles that have had their IC (intercooler) pumps up and fail. Not a month goes by that I do not get a Lightning to dyno tune that has a bad IC pump. Before I dyno tune them, I do check every supercharged vehicle with an IC pump for proper pump function, but one can also easily determine via a datalog if something is out of ordinary with the IC system. At times I'll get a vehicle in with the IC pump working, but somewhere along the line it stops working (not too often, but it does happen). Having my datalogging program set for me to be able to see post-blower temps can allow me to abort a dyno pull before its too late.
Quote:
Apparently the OEMs felt the risk was very very small.
Being that this applies to your first paragraph of your post, it doesn't any longer apply. However, I do want to state that Ford, and other OEM manufacturers, do feel that proper placement of the IAT sensor is very critical to proper function of the system as a whole. Ford put the IAT2 sensor on their supercharged cars to after the blower purposely, and for good reason, and exactly why I explained above.
Quote:
Zack, your answer is right there for you. Just ask Powersurge and Lidio what they do with IAT sensor readings for intercooled SC applications and you'll have an even more obvious answer.
I know Powersurge (Sal, if that is him), quite well. I'm actually surprised he didn't know that IAT2 is the one the pcm uses for spark function. Are you sure you didn't mistake him?
Quote:
Another thing to consider is that we haven't seen FoMoCo do a recall on the eaton Supercharged Cobra to update its use of the IAT2 just because they figured out how to do it for the new Shelby. Technology advanced and the IAT2 is now optimally placed. But that doesn't make the previous application unreliable or unsafe.
FoMoCo won't have to recall, because they already have it placed and utilized by the pcm properly, and that's the exact same way they are doing it even on the new Shelby (btw, which I have one on order; OMG I can't wait!).
I realize I've already disputed correctly the incorrect information you were given, and I don't want to keep reiterating the facts over and over, as that can be viewed as somewhat a slap. However, since you now know the information you were given was indeed incorrect, I'm sure you can feel more confident in knowing the realities of the matter.
Now, in regards to retuning a vehicle that has the IAT sensor moved to post-blower, someone, and I can't recall who, stated it would take a lot of work to redo the programming to work with the relocation. That's actually very incorrect, as well. Fact, it takes about 30 to 60 seconds to rescale the pcm's IAT parameters for relocation of the IAT sensor. There is actually only 1 that needs to be rescaled, tho better use of the pcm's IAT spark function can come by rescaling two parameters. Since I dyno tune so many Cobras and Lightnings, and various other supercharged vehicles, I know exactly where these parameters should be set.
Everyone, my information given is for the benefit of the entire aftermarket industry. Please understand that I would not give it out for any reason other than to help, especially when I see that it is needed. Proper education of individuals within this industry and community has always been my ultimate goal.
I do not plan to post here often, tho I hope I am welcome to give my professional expertise from time to time, because I can assure you that it is very valuable.
Very Sincerely,
James
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Last edited by RWTD; 12-10-2006 at 03:36 AM.
Last edited by sailsmen; 08-11-2010 at 08:02 PM.
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