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LH Performance Modification Discussions
 #385339  by twincharged30
 August 3rd, 2020, 12:45 pm
Hello,

I am new to this forum

Hope all is well

I've been in discussion with Plymouth Prowler performance company (https://theprowlerstore.com)that does PCM tunes for them (Prowlers use the same engine and transmission). The contact told me that he/she can put the same tune on 300M or any other LH platform with 3.5 H.O., the company claims it gives another +25-35 HP Gain. they charged $445 (not including shipping)

So im letting everyone know about this, also i was informed if 3 or more send them in as group purchase he/she will take off 15% of the cost

Im thinking of doing this for my car, so if other people would like to do this also, please contact me so we can save some $$$$

This PCM Upgrade is designed for stock or with some modifications (performance exhaust, cold air intake, headers). Upgrades include:
► Revised Premium fuel & timing tables
► Rev limit raised
► Speed limit raised
► No torque management

Thanks

Dustin
User avatar
 #385347  by Sneke_Eyez
 August 3rd, 2020, 4:14 pm
Dustin, welcome to the Club.
Thank you for sharing this with us.
You will certainly fit right in as many of us are passionate about these cars and unique modifications for them.

What I'm curious about with something like this (for myself and anyone) is whether they are equipped to tune 02-04 PCMs or just 99-01 PCMs?
Their site does not specify.

I would have a number of questions for their tuner about the upgrade before I could follow through with it.

As an example:
My Intrepid (which has a full 02 300M Special PCM conversion) already does not upshift until 6500RPM when in Autostick.
Frankly, I wouldn't see the benefit of a completely removed redline - if that is what is what is meant by "rev limit raised."
Perhaps this would be more valuable for a "base" LH PCM, which does not have the tuning of a Special PCM.
User avatar
 #385349  by LUNAT1C
 August 3rd, 2020, 5:04 pm
I'm not terribly familiar with the Prowler's PCM system. All I know about it what I learned from the videos posted by Hoovie's Garage on YouTube when he bought a 1999 Plymouth Prowler and installed the uprated TCM and PCM. That might be the same as the 1998-2001 computer system for LH cars, not entirely sure.

For 02-04, LH cars switched to a unified PCM/TCM (All one unit) that no aftermarket performance tuning house has been interested in cracking. I'd be curious if the Prowler ever made that switch as well. Considering it went out of production within one model year of the LH series being refreshed and receiving that single PCM, and being extremely low volume, I'd guess it never did have the single module.

I guess what a lot of folks will want to see is evidence that they can safely crack and modify the single LH module, as it does differ from the dual modules used in the early 2G LHs and the Prowler.

Also, I'd be curious as to the expected real world performance gains. As it stands, Special PCMs happily rev to 6500 RPM and technically do not have a speed limiter (the car is aerodynamically limited to 149 MPH, supposedly). I'm not sure what performance gain is expected from the new fuel/timing maps and removal of torque management. I also do not know what removal of torque management refers to... do they have a published resource that explains all of this? Is there a thread on a Prowler forum that contains what those guys have said they've experienced? I know Tyler Hoover was giddy with excitement when he upgrade the PCM, the TCM, and the gears, but remember that Special's already have upgraded gearing (they didn't state what his Prowler was upgraded to though) and don't have the same PCM setup.
 #385356  by twincharged30
 August 4th, 2020, 7:58 am
Sneke_Eyez wrote: Sneke_Eyez
Sneke Eyez,

I did inquire about this before i posted this to the forum. i had picture of the 2002-2004 PCM and explained how it is i a different physical configuration than the Prowlers ECM. The contact did assure me that this was not an issue and i did a double check with them, they said it was not an issue.

To be honest, not worried about the rev limit update whether it applies to the special, im more interested in the deactivating the torque management and fuel map tables for premium fuel. this will give these cars better performance in my opinion. (FYI it hard to determine whether someone being aggressive or smart (CENSORED) in text, i do not have that tone lol)

by the way nice looking Intrepid!! i like it

Thanks

Dustin
User avatar
 #385357  by Sneke_Eyez
 August 4th, 2020, 8:50 am
twincharged30 wrote: August 4th, 2020, 7:58 am Sneke Eyez,

I did inquire about this before i posted this to the forum. i had picture of the 2002-2004 PCM and explained how it is i a different physical configuration than the Prowlers ECM. The contact did assure me that this was not an issue and i did a double check with them, they said it was not an issue.

To be honest, not worried about the rev limit update whether it applies to the special, im more interested in the deactivating the torque management and fuel map tables for premium fuel. this will give these cars better performance in my opinion. (FYI it hard to determine whether someone being aggressive or smart (CENSORED) in text, i do not have that tone lol)

by the way nice looking Intrepid!! i like it

Thanks

Dustin
That's good that they know about the difference in PCM style.
My concern is the real world performance gains of the programming.
I already run my Intrepid on premium fuel only (as opposed to my DD 04 Special that I put nothing but regular into), so the premium fuel tune is interesting to me, but one thing I've never clarified is the real world performance differences between a Prowler PCM and a 2002 Special PCM - I've never driven a Prowler (something I'd love to do).
Are they raising the bar past the 2002 Special programming? Or is it simply catching up?
Frankly, my Intrepid has pretty decent performance for a 250hp family sedan designed in the mid nineties.

I am interested, but $500 is a lot to drop when I don't know much about the actual gains.
I'd love to see someone do this and have their car dynoed before and after the upgrade.
User avatar
 #385359  by LUNAT1C
 August 4th, 2020, 10:22 am
It's definitely good that they're aware of the physical differences. I'd be interested to know how it is they've come by the confidence that they can do it. If I could source a good working 02 Special PCM as a spare to send in, I might be more confident about it (no idea if my local yards have any, I've skipped grabbing the PCM in the half dozen I've seen in the yards in the last decade).

I'll see what I find myself on the Prowler sites, but do you have any links from Prowler owners showing their real world experiences?
User avatar
 #385362  by FIREM
 August 4th, 2020, 1:16 pm
I would proceed with extreme caution on this topic.
Not much if any chatter on the Prowler site about this ( I am registered there and do stop in from time to time)
Typically Prowler folks looking for more power just drop a Hemi in and call it a day.
They did dabble with Superchargers and other attempts but no real quick gains for $500.
As far as "Torque Management" one thing I am aware of, (from discussions with Don Scruggs/Red Barron) is injectors cutting off at trans shift points. Dropping less cylinders at shift to preserve the trans was programmed on the Prowlers but not on the LH's. I think the LH's drop 3 and the Prowlers only drop 1.
Would be good to see some posts about real world results first.
User avatar
 #385372  by mundajames86
 August 5th, 2020, 12:36 am
...so, I guess we are waiting for you to move forward and let us know if you got "a mo powa, baby!"
twincharged30, StealthM liked this
 #385431  by twincharged30
 August 12th, 2020, 2:25 pm
sorry i have been busy

well everyone got to do what they are comfortable with

thanks
 #386673  by TheBurningRom
 November 29th, 2020, 1:35 am
Did anything ever come of this? :)
User avatar
 #386674  by FIREM
 November 29th, 2020, 6:30 am
Nope and never will
 #386960  by twincharged30
 January 4th, 2021, 9:12 am
Well hello MR. negative!! (FIREM). Actually just got the ECM back from them, waited until black Friday to buy the tune.

I will privately PM anyone interested on this subject and outcome of the ECM tune. I did take a post-tune performance measurements and will share the difference also

I'm not trying negative, but I see now why the after market performance never bloomed or flourished for this these cars with enthusiast such as FRIEM and other being pessimistic or bleak on trying and researching new thing for these cars. I would love to go into more details on how engine performance is not "magic" just math, engineering and knowledge!, but not going to waste my energy with obtuse people on forums (been down this road before with 3000gt/Stealth forum, always naysayers and and chest thumpers)

Thank you

Happy New Year!!
 #386961  by StealthM
 January 4th, 2021, 11:08 am
What's the point of joining a forum if your not openly willing to share information that you have gathered? Why should we request a PM? Is it super secret math that you have their. Many people on this forum have been here since the the car has been around and well versed in the mechanics of it. For you to question there knowledge is insulting. When it comes to increasing the engine performance of these cars people will have an interest. So if you got some snake oil to sell lets ALL HEAR IT.. if you can't be part of the collective, and share what you have, then keep it too yourself. Good day sir....
twincharged30 liked this
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 #386962  by LUNAT1C
 January 4th, 2021, 11:10 am
Glad you were able to get something. I'm sure many folks would be interested to know the outcome (genuine performance increase result, any issues with the upgrade, impact to shifting, etc.). I'm very curious if they were able to work with the 2002-2004 PCM, since it's very different from the 1998-2001 PCM and TCM separate module arrangement used in the Prowler. Historically, the LH PCM has not been moddable due to it being locked down tight by DiamlerChrysler and no suitable ROI for an aftermarket company to crack it.

The problem with the aftermarket isn't "naysayers". We've been down this road multiple times with multiple aftermarket manufacturers. Since these cars were designed and made to simply be transportation (get to work and back grocery getter and Sunday Church driver with a "sporty feel"), the vast majority of 1st and 2nd owners back when they were in production weren't interested in upgrades. Heck, 1st owners of 2002 Specials complained enough about the transmission tune that Chrysler detuned and softened it for 2003-2004. Because of that, the aftermarket companies couldn't make a case for it with a positive ROI for them. So, we've been left to DIY nearly everything we've accomplished. And sure, a lot of folks have become a bit pessimistic at times when this topic comes up.
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 #386967  by Sneke_Eyez
 January 4th, 2021, 3:44 pm
twincharged30 wrote:Well hello MR. negative!! (FIREM). Actually just got the ECM back from them, waited until black Friday to buy the tune.

I will privately PM anyone interested on this subject and outcome of the ECM tune. I did take a post-tune performance measurements and will share the difference also

I'm not trying negative, but I see now why the after market performance never bloomed or flourished for this these cars with enthusiast such as FRIEM and other being pessimistic or bleak on trying and researching new thing for these cars. I would love to go into more details on how engine performance is not "magic" just math, engineering and knowledge!, but not going to waste my energy with obtuse people on forums (been down this road before with 3000gt/Stealth forum, always naysayers and and chest thumpers)

Thank you

Happy New Year!!
You'll have to excuse the longtime owners of these cars if we're skeptical and want to ask questions before we spend our money.
Nobody wants to make anything for these cars anymore. Chrysler doesn't even make OEM parts for them anymore, never mind aftermarket tune options.

Lots of companies have made promises about tuning these cars through the years and they have not come to fruition.
They overpromise and don't deliver or underdeliver.

The fact that you found a company who actually delivered a tuned PCM to you is amazing.
The fact that you don't want to share it because of one member here on the Club site who may have been negative is a shame.

From the outset several people told you we were interested in more information and may be interested in a tune.
I was one of them, actually, I was the first reply, with several questions.
I think we both can acknowledge that my Intrepid would be a pretty good candidate for a tuned PCM.

However, little information was provided on what they would really do to a PCM, you didn't seem to be able to answer our questions (which is just fine, you weren't doing the tuning). Several people asked questions, got no information back, and that was that.
Now you are back, you bought the tuned PCM, you're the guinea pig, you say you have measurements, and you don't want to share information with us.

Of course PCM tuning is just math and engineering - that's why so many modern cars have tuners available.
The problem with our cars is that nobody ever "broke" the PCM encoding, so we couldn't change anything in the PCM programming to change tunes. Several different tuners tried, no one was successful. Several tuners through the years said they could, then didn't/wouldn't do it. Now that there are less and less of our cars on the road, it seems even less likely that any aftermarket company would want to work with them.

Frankly, if that company wants to tune our cars, there is no larger home of real LH car enthusiasts for them to speak to/share results with then right here on the Club forums, so they should share information here. I'm not looking for HOW they cracked the PCM, I'm just looking for what changes they make since they cracked it - how will the tuned PCM benefit my Intrepid that already has the best of the LH car PCMs?

It seems to me that you may have the answers to that question - I'd like it if you shared them here.

Every interaction on the internet brings out naysayers - our forum is filled with people who had promises made to them by aftermarket companies who failed to deliver - it is up to you to be the person who helps provide real information since you followed through and bought the PCM.
User avatar
 #386970  by FIREM
 January 4th, 2021, 3:54 pm
twincharged30 wrote: January 4th, 2021, 9:12 am Well hello MR. negative!! (FIREM). Actually just got the ECM back from them, waited until black Friday to buy the tune.

I will privately PM anyone interested on this subject and outcome of the ECM tune. I did take a post-tune performance measurements and will share the difference also

I'm not trying negative, but I see now why the after market performance never bloomed or flourished for this these cars with enthusiast such as FRIEM and other being pessimistic or bleak on trying and researching new thing for these cars. I would love to go into more details on how engine performance is not "magic" just math, engineering and knowledge!, but not going to waste my energy with obtuse people on forums (been down this road before with 3000gt/Stealth forum, always naysayers and and chest thumpers)

Thank you

Happy New Year!!
Sorry if I offended you Dustin.
"We", as in this family of enthusiasts have tried a number of times to have performance and other upgrades for the LH platform , ( especially when these cars were newer and more lucrative for the aftermarket to respond to)
"We" have had success with one particular vendor for suspension parts but that's about it. Others have come before you with alleged performance tuning that did not come to pass. Any upgrades that work have been developed and shared by supporting members of this site.
Enjoy your new enhanced performance, before and after dyno results would be welcomed.
FWIW a little casual recommended reading : https://300mclub.org/forums/viewtopic.php?f=2&t=36915
 #387382  by Feardamichael
 February 24th, 2021, 12:05 am
twincharged30 wrote: January 4th, 2021, 9:12 am Well hello MR. negative!! (FIREM). Actually just got the ECM back from them, waited until black Friday to buy the tune.

I will privately PM anyone interested on this subject and outcome of the ECM tune. I did take a post-tune performance measurements and will share the difference also

I'm not trying negative, but I see now why the after market performance never bloomed or flourished for this these cars with enthusiast such as FRIEM and other being pessimistic or bleak on trying and researching new thing for these cars. I would love to go into more details on how engine performance is not "magic" just math, engineering and knowledge!, but not going to waste my energy with obtuse people on forums (been down this road before with 3000gt/Stealth forum, always naysayers and and chest thumpers)

Thank you

Happy New Year!!

I 100% am interested in this tune!! If you could PM me the results I’d love to get in contact with you and see what kind of differences they made to these cars??

Thanks so much
User avatar
 #387385  by FIREM
 February 24th, 2021, 8:38 am
Feardamichael wrote: February 24th, 2021, 12:05 am
twincharged30 wrote: January 4th, 2021, 9:12 am Well hello MR. negative!! (FIREM). Actually just got the ECM back from them, waited until black Friday to buy the tune.

I will privately PM anyone interested on this subject and outcome of the ECM tune. I did take a post-tune performance measurements and will share the difference also

I'm not trying negative, but I see now why the after market performance never bloomed or flourished for this these cars with enthusiast such as FRIEM and other being pessimistic or bleak on trying and researching new thing for these cars. I would love to go into more details on how engine performance is not "magic" just math, engineering and knowledge!, but not going to waste my energy with obtuse people on forums (been down this road before with 3000gt/Stealth forum, always naysayers and and chest thumpers)

Thank you

Happy New Year!!

I 100% am interested in this tune!! If you could PM me the results I’d love to get in contact with you and see what kind of differences they made to these cars??

Thanks so much
Sorry to say "Dustin/twincharged30" has not visited the site since 01/04/21 and we suspect never will. Unfortunately PCM Performance tuning is just not happening for our cars.
 #387390  by StealthM
 February 24th, 2021, 1:46 pm
Churp,churp..... yep thats what I thought too. 😥😥😥