[GTRonn]

There's been a lot of car side discussions while people and my friends check out my new ride. I just wanted to post some of them in hopes you can help decide which ones are myths and/or facts.

1. All new cars (such as my 07 Mustang) have computer processors that keeps track of your driving habits, so it can adjust accordingly based on historical data. Therefore if you baby your car too much, it will feel underpowered when you get on it.

2. Carbon and other fuel combustion byproducts can build up on the plugs, cats, valves, etc. overtime which is why it is a healthy practice to rev up your engine hard every once in a while to help clear it up.

3. If I keep the boost on my Saleen supercharger on or below zero, I am using enigne power alone without the aid of the forced air from the SC. This saves gas during acceleration.

 

[StalkerStang]

Number 1 is true, the PCM will learn your driving habits. If you drive like grandma and never drive over 40 mph and never go above 3000 rpm's, then the PCM will optimize the timing, fuel curves, etc. to make that type of driving as smooth as possible and to where it will get the best gas mileage at those rpm's and speeds. Its all about emissions though, reducing the most amount of by-products at how ever you drive the car. Its not permanent though, if you change the way you drive for long enough, the PCM will re-learn that style of driving.

Number 2 I have heard of, don't know if its really true. I think its more true with older vehicles then new ones. I know cars in the 80's and 90's that have EGR are usually really dirty inside and built up with carbon.

Number 3 is mostly true. If you stay out of the boost, the PCM doesn't have to add the necessary fuel to accommodate the large amount of air coming in. Less fuel, better mpg.

 

[Gotadime]

Nice questions. I'd say that Stalker gave you all the answers you need. I say: "I always can appreciate another reason to rev up that engine!" :bigthumbsup

 

[myltlpny]

That's pretty much what I was going to say verbatim, Stalkerstang.

 

[RedMosesSC]

I read in the manual that the computer records driving actions, in case of an accident law enforcement can better understand the actions preceding the incident. Apparently they need your consent to gain access to this data but...

Carbon build up on the plugs and all that is by design from "Oil blow by", an oil separator/catch can will remedy that.

 

[farnsworth]

I have no evidence to base this upon, but wouldn't a supercharger that isn't supercharging be robbing the engine of horsepower(since it's still turning the pulley and the blower)? What are you comparing the s/c-with-no-boost against?

 

[GTRonn]

I have no evidence to base this upon, but wouldn't a supercharger that isn't supercharging be robbing the engine of horsepower(since it's still turning the pulley and the blower)? What are you comparing the s/c-with-no-boost against?

Just by looking at the boost gauge. I guess you are right, if it's not giving boost, it is making the engine work harder. Then again, how good is that Saleen S/C bypass? Is that a complete bypass until boost gauge goes over 0 lbs? You can imagine how this topic can take several minutes with a bunch of car guys that don't have a lot of technical knowhow.

 

[GTRonn]

I read in the manual that the computer records driving actions, in case of an accident law enforcement can better understand the actions preceding the incident. Apparently they need your consent to gain access to this data but...

True, but that's for a different application. Is that same data being used by the processor to maximize fuel mileage, performance, etc...

 

[pcfrisch]

You can also reset the PCM by disconecting the battery for about 1/2 hour.

I read in the manual that the computer records driving actions, in case of an accident law enforcement can better understand the actions preceding the incident. Apparently they need your consent to gain access to this data but...

Carbon build up on the plugs and all that is by design from "Oil blow by", an oil separator/catch can will remedy that.

They can get the info from a court order. Usually if the accident is fatal.

 

[StalkerStang]

You can imagine how this topic can take several minutes with a bunch of car guys that don't have a lot of technical knowhow.

Speak for yourself, lol :gringreen

The accident data is more or less a data logger. But the PCM uses that data to form its strategy for changing the tune of the vehicle to accomodate your driving style.

 

[XR7GTVIII]

I thought ( basically from what I've read ) that the PCM only recalibrated the auto tranny based on driving conditions............

 

[Rice05eater]

I thought ( basically from what I've read ) that the PCM only recalibrated the auto tranny based on driving conditions............

I understood the last to be true as well, and didn't it first come out on the 99 stang?

 

[StalkerStang]

They are much more advanced now, I can't give you an exact year, but most OBDII vehicles have this capability to adjust to driving styles...

It goes pretty in depth on how it does it. The PCM monitors short term and long term fuel trims, TPS, engine load, I mean I could go on forever.... But especially now since most cars have electronic throttle control, the control the PCM actually has over the car is pretty amazing (sometimes scary).

Even more so in the explorers and expeditions that have RSC, and the bigger cars like the crown vics and mercury's that have electronic steering.

 

[tached_out]

thats why i love my procharger i was driving it with my new street tune and i got 20mpg on the street and 27 on the high way lower compression motor and centrifugal blower

 

[Mic5rbns]

Just by looking at the boost gauge. I guess you are right, if it's not giving boost, it is making the engine work harder. Then again, how good is that Saleen S/C bypass? Is that a complete bypass until boost gauge goes over 0 lbs? You can imagine how this topic can take several minutes with a bunch of car guys that don't have a lot of technical knowhow.

granted your not always in the boost mode, you are still getting air feed to the engine better than a n/a one.. mine runs and sounds good through all modes.

 

[stlwagon]

#3 is absolutely true. :bigthumbsup

 

[Executioner]

So does the PCM learning apply if you have an aftermarket tune?

 

[ski]

Going WOT may not help to prevent carbon build(Read: pinging) up if one continuously uses poor quality gas, and drives mostly short trips that do not allow the engine to reach normal operating temperature. A can or 2 of Seafoam can help to get rid of it.

 

[grabborange]

So does the PCM learning apply if you have an aftermarket tune?

My understanding is an aftermarket tune turns it off. So, it's no longer adaptive it is locked in for aggressive driving styles that we all seem to have.

 

[GTRonn]

My understanding is an aftermarket tune turns it off. So, it's no longer adaptive it is locked in for aggressive driving styles that we all seem to have.

There's something true about that with what I experienced. When we took a bunch of hard revving joy rides one day, my mpg showed 13. When I drove is very calmly one day (shifting between 2000 to 2500 rpm) my mpg went down to 12mpg. I did reset the avg mpg that calm day to get accurate reading for my change in driving behavior. I did same thing on hwy at 75mph with cruise control, making 24 ave mpg.

I really don't care for mpg when I'm in my GT, otherwise I'd be in my Taurus. This is just something to tickle the membrane.:scratchchin