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Under cruise conditions the Manifold Air Pressure sensor (MAP) acts like a barometer, and sends this info. to the Power Control Module (PCM), which in turn adjusts injector pulse width to maintain the 14.7:1 air-fuel mixture. This is the main input that controls mixture at different altitudes. The Intake Air Temperature sensor (IAT) provides input for changes in temperature. It's really a pretty complex, yet neat setup, but would be better if it were a Mass Air system. The limits of our Speed Density system are mainly the pre-programmed limits/ranges of the PCM. These limits/ranges are designed to accomodate nearly all environmental conditions we are likely to encounter. To indicate the complexity at cruise, for instance...the PCM adjusts mixture by using inputs from MAP sensor, RPM sensor, IAT sensor, engine coolant temperature, camshaft position, knock sensor, throttle position, 02 sensors, air conditioning switch position, battery voltage, and vehicle speed. At Wide Open Throttle (WOT) inputs used ar IAT sensor, engine coolant temp., RPM, knock sensor, MAP sensor, and throttle position. The fuel injection system also has built in pre-programmed short and long term fuel correction (adaptive memory) routines that are triggered anytime mixture reaches a predetermined "switch" point. The adaptive memory is a whole different bucket of worms though. My head hurts! Guess we've pretty much beat this to death.
With regard to Cold Air Intakes (CAI's), the main approach I used is that the cooler air (denser) in, the better for performance and gas mileage. Really though, at this point I am more interested in the gas mileage. This is why my home built CAI utilizes an additional air inlet from behind the grill to the airbox (in addition to the stock "eardrum" inlet in the fenderwell), a double insulated stock airbox, a K and N drop-in filter, and a double wall, double insulated intake tube from filter to plenum. I don't know if this, by itself, works, but I do know that with this and my other minor mods., my in-town and highway mileage has increased significantly. I now get 15-18.4 mpg in town/rural, and 27.5-28.3 mpg on the highway between 60-70 mph. I have recently changed to synthetic oil and will be taking 600 plus mile trip next week. It will include mountain, flat land, and rolling hills. I hope to do even better now. For those who doubt, a true COLD AIR kit...not drawing heated underhood air is a good investment IMO. If anyone is interested on how I did mine, I'll start another thread that specifically addresses my CAI. Let me know.
Yeah, I know the thread's old, but I'm looking for something and this is interesting. Magnuman's Post is the closest to real operation.

Two things to consider at WOT.

1) The long term adaptive memory does impact fuel/air mixture settings. As quoted from the service manual:
"The values stored in long term adaptive memory are used for all operating conditions, including open loop and cold starting"

2) During WOT "The PCM adjusts injector pulse width to supply a predetermined amount of additional fuel, based on MAP and RPM."

I'm searching for people experimenting with changing the sensor value for the IAT sensor to adjust the fuel/air ratio. However, this needs to be done only at WOT or you impact the long term adaptive memory and could negatively impact closed loop modes. (The O2 sensor readings may compensate for this, however....)
 

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jaak,
I've got it!! I also did that quite a while ago. It's worth about two tenths of a second at the drags...if you're lucky enough to guess at the right setting. As you said, it only will work at WOT (open loop), but won't do squat when cruising or anytime you're in closed loop, which is most of the time. As you stated, if you leave it on all the time, the adaptive memory will begin making compensations for its presence, thereby negating its effect. Here's the link for it: http://www.300cforums.com/forums/pe...5-mixture-control-wide-open-throttle-wot.html
Note that I've since added the switch so I can now go rich or lean. I will usually go about 20 degrees above or below ambient. Since most folks that have dyno'ed their Hemi's have found a slightly richer mixture through mid and high RPM ranges, I have been going to the lean side, which is a higher temperature setting on my pot. I use the EVIC for the ambient temp. and set the desired temp. using my ScanGauge reading directly off the IAT sensor for the "phony" setting.

I've recently been running some new temp. tests between ambient, the airbox, and the IAT sensor. The airbox (after stabilization) runs at ambient, or a couple degrees cooler. The IAT, on the other hand, even with my double wall, triple insulated intake tube, normally will run 2-40 degrees warmer than the airbox/ambient temp. It depends on the type of driving....in town long stop and go in 90 degree weather, it'll run between 25-40 degrees above. On the highway at the same ambient, it'll usually run 2-20 degrees above, depending mostly on heat soak and throttle opening. More throttle....more airflow, equals lower IA temp., and vice versa. I've got an idea to run almost continuous ambient airflow between the double walls of my tube, with hopes of cooling it down a little more (retard heat soak), without much additional plumbing. Just have to find time to do it.

Also, since that original IAT posting, I've removed the ear drum silencer and run a 4 in. duct from the bottom of the airbox to behind the lower grill. So, all my intake air into the box is unrestricted, and at ambient. I've also added the Daytona suitcase muffler, SRT8 airbox cover, and the SC Tuner. I've gotten legit. (figured with calculator) 30 plus MPG numerous times since. Highest, so far, is 33.6. That was using the 91 tune, 87 fuel, with 6 oz. of acetone, driving 60-70 mph. Not something I will normally do though, especially as the temps. warm up.
 

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I posted in that thread, thanks magnuman!

I've got a circuit to build... If it works out, I'll share it, as it means no switch for WOT. Instead it will switch automatically for you... Just gas and go!
 

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volant

Hi

yeah u r right bro. i installed the volant to my 300C with the borla cat back system 5-inches.. beleive me guys it's totally different.... BUT,,,u need a programmer.. the american cars designed on a system that u can't change it or adjust it, if u installed something new to the car..it would not be accepted it and may goes to worse. I'M NOT talking about all the 300C cars... it's rear that u installed borla with volant and there in increase in the Hp...

good for u friend.
 

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I may be confused here, but no one has mentioined pulling of fuse 11. My understanding is that causes the computer to re-learn everything, including air/fuel mixtures
 

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300CmeFLY said:
I'm will be putting on a Volant air intake soon, and I was always under the impression that the computer would automatically re-adjust for the increased airflow through the intake. Then I happened to read a section in this artilce, and it states that it would have to be reprogrammed. Here's the link, and quote:
http://www.popularhotrodding.com/tech/0403phr_hemi/
"Unlike an LS6, which has a mass air system that allows the computer to adjust the fuel flow for any given airflow so that the mixture is always right (theoretically at least), the Hemi has a speed density system. This means that any increase in airflow into the engine goes unseen by the rest of the system. If a modification is done that increases mass airflow, such as a cold-air package, the computer has to be reprogrammed accordingly. Fortunately, two companies, Squier Inc and Street & Performance are working on this now and already have what is needed for transplants of the Hemi into other vehicles."

Is this the case? :confused:
I am having Magna Flow with 3" mid pipes and high flow cats and an AirAid CAI installed this Thursday. I am having a before and after Dyno done, so i will be able to see what HP impact there is. For me, the mods are going to make the car sound as mean as it drives (with maybe a little faster launch time). Dyno Comp is installing for me, and they say by their experience, this will add 30-40 HP, we will see.
 

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hi all
i installed a DUBAIR cold air intake,, but i didnt know any thing about re-programmmming the Computer,,
plz update me ):
 

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aussaleen said:
hi all
i installed a DUBAIR cold air intake,, but i didnt know any thing about re-programmmming the Computer,,
plz update me ):
A few ways:

1. Take it to the dealer, say you disconnected your battery and now it runs like SH!T

2. Unplug fuse 11 for 15 seconds or so, then plug it back in. (That is fuse 11 under the hood, not in the trunk)

3. Use the Superchip Flashpak, unless you own a late model 06, then you are SOL for a few more weeks...
 

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Question about reprograming

I have a 2006 300c bought in 2005. I have mopar headers, borla exhaust, air raid filter, 180 deg therm, throttle body spacer, & stage 1 Jet Chip.

The car sounds great and feels strong but I definately do not have the performance that I would expect from these mods.

1) does the jet chip, reprogram the computer for these mods or do I still need to pull fuse 11?

2) I have a stage 2 chip and DUB air intake on the way, does it make sense to send the stage 2 jet module back and just buy a Superchip flashpak?

3) I like the idea of the Jet Chips because I don't need to enter any info. I wouldn't know what to set the parameters at in the superchip flashpak. With the flashpak, can I tell it my mods & it comes up with the best program? Or do I need to "tell it what to do" and it does it?

4) If i pull fuse 11 do i need to uninstall the jetchip first and reinstall after?
 
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