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SRT Engineers Roundtable: 01/26/11

127K views 209 replies 85 participants last post by  DMAG 
#1 ·
SRT Engineers Round Table Discussion

Wednesday, January 26th 5pm - 7pm ET

The ground rules:

  • First off, the SRT Engineers take time out of their busy schedule making go fast goodies to be here to answer our questions. Let's show them the proper courtesy and patience. There will be many questions and they may not be able to answer every question asked. If your question is skipped, please be patient as questions are not answered in order.
  • Please only ask one or two questions. There are lots of people who want to ask questions, so let's give everyone a chance.
  • Stay on the topic at hand. SRT Vehicles! Keep the off-topic chat to the other sections of the website. There is to be no discussion between members in this forum. Ask your question and enjoy the replies from the Engineers!
  • If your question has already been asked (by you or someone else). Don't re-post it in hopes to get it answered quicker.
  • Make sure you let the SRT Engineers know what model SRT vehicle you are driving or inquiring about. Yes, a head gasket is quite different between an SRT8 and an SRT4. :wink:
  • As much as everyone is salivating over what comes in the future, the SRT Engineers cannot answer any questions regarding future product.
This thread is now open for you to post your questions!
 
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#2 ·
The thread is now open for you to post your questions. Please read the above rules and read questions others have posted first to make sure your questions have not been asked yet.

Thanks to you and thanks to the SRT Engineers for giving us this opportunity to learn more about these incredible vehicles!
 
#3 · (Edited)
Glad you have elected to return and answer questions, we really appreciate it;

There is conflicting information regarding the Magnum's F/R weight distribution; can you enlighten us please, specifically the RT/SRT version. Thanks!
 
#10 ·
My questions:
Do you guys have any aerodynamic data for the SRT8 Magnums? I'm mostly interested in front and rear lift, but I'll take anything you've got.

Also: Do you know the motion ratio for the SRT8 Magnum's front coilovers, rear shocks and rear coils?

Thanks!

There is conflicting information regarding the Magnum's F/R weight distribution; can you enlighten us please, specifically the RT/SRT version. Thanks!
My SRT8 with very little gas, the rear trays removed and the Mopar hitch:
1128 1108
975 1029

Thats 52.7% front, 4,240 total.
 
#5 ·
Hello SRT Engineers!

First and Foremost a Sincere Thankyou for allowing this 60 year old to relive his youth of the Muscle Car era! I have not had this much fun since 1967 to 1971! My 2010 Dodge Challenger SRT 6-spd is a BLAST to drive! I have 2000mi's on it b-4 it went into winter storage.

My first question is the Tremec 6060's gear nibble in 2nd and 3rd? If I double clutch there is none, but with normal shifting below 2200rpm there is a persistent nibble, but at 3500rpm it appears to float smoothly into gear. I have called Tremec and their response was YES there is an issue, contact your dealership. My dealership claims there is NOT! Or is heavier loading needed(more break-in time)?? Per my tranny's serial# TUET 10430BL2493 P05038209A6 04918 it was produced 11-24-2009 on 3rd shift

Also the wheel hop issue? Does Mopar have a suggestion to a more solid fix than heavier motor mounts? Such as a No Hop kit, or a Mod from Mopar?

Thanks Again for helping us GEAR-HEADS keep smiling! :-D


Teo
 
#78 ·
Hello SRT Engineers!

First and Foremost a Sincere Thankyou for allowing this 60 year old to relive his youth of the Muscle Car era! I have not had this much fun since 1967 to 1971! My 2010 Dodge Challenger SRT 6-spd is a BLAST to drive! I have 2000mi's on it b-4 it went into winter storage.

My first question is the Tremec 6060's gear nibble in 2nd and 3rd? If I double clutch there is none, but with normal shifting below 2200rpm there is a persistent nibble, but at 3500rpm it appears to float smoothly into gear. I have called Tremec and their response was YES there is an issue, contact your dealership. My dealership claims there is NOT! Or is heavier loading needed(more break-in time)?? Per my tranny's serial# TUET 10430BL2493 P05038209A6 04918 it was produced 11-24-2009 on 3rd shift

Also the wheel hop issue? Does Mopar have a suggestion to a more solid fix than heavier motor mounts? Such as a No Hop kit, or a Mod from Mopar?

Thanks Again for helping us GEAR-HEADS keep smiling! :-D

Teo
The cars we have shift with the presicion that we have come to expect from the TR6060. Personaly I like to feel each and every segment of the shift rather than a numb/dead stick. I've heard some peolpe describe this a notchy, but if your getting nibble that's something different. If the car is cold you might feel something and I would consider that normal and par for the course on a high performance trans. I don't know who you talked to at Tremec but we have not seen an issue on a warmed up car. If you are seeing an issue the dealer should be able to reproduce it.
 
#6 ·
On an '08 srt charger, why is there so much bump steer? Would you have a suggested solution to this problem in the way of a fix? Perhaps a certain popular kit, that involves bushings. This bumpsteer can get a little hairy at times. An example would be those times when you get out of the groove a little at the big end of the strip. The car starts going all over the place.
 
#64 ·
Based on the signature, your vehicle has had several modifications done to it. Any changes to the front tires, tention links, suspension bushings, or power steering could have a negative effect to bump steer. We would recommend inspecting your front supension bushings for any exessive wear, and replace them as required.
 
#9 ·
Thank you all for taking the time to answer our questions and share your knowledge with us.
My question is in regards to the new MPTCM for the SRT's. Other than already being pre-programed with the 3.06 gear ratio, what makes this more advantageous than the previous MPTCM? Can you share some of the Specs with us? Shift points, TC lock, line pressure ect...

Thanks again for taking the time to be with us.
 
#70 ·
Thank you all for taking the time to answer our questions and share your knowledge with us.
My question is in regards to the new MPTCM for the SRT's. Other than already being pre-programed with the 3.06 gear ratio, what makes this more advantageous than the previous MPTCM? Can you share some of the Specs with us? Shift points, TC lock, line pressure ect...

Thanks again for taking the time to be with us.
The two part numbers are very similar except for the gear ratio difference you mentioned. In repsonse to customer requests we introduced an SRT version of the 5.7L Performance TCM. The calibration was optimized for use with the Mopar Performance Torque Converter and also includes the hold in gear feature. Performance gains will be greatest for those customers with a higher slip converter.
 
#11 ·
I have an 2009 Challenger SRT, automatic. It seems to have two different issues starting. Twice (once the outside temperature was high 20s, the second time outside temperature was in the mid 40s) I've used the push button start from inside the vehicle. The starter turns over, but doesn't engage the engine. To get the car to start, I have to pull out the push start button and insert the key. Today when it happened, the car started for about two seconds then quit. Then did the starter thing. It started fine with the key fob inserted. Any ideas on what is happening?

The second issue is the remote start does not always remote start. It seems to happen more on colder days, than not, but this is not always the case. I cannot find a definite pattern for when the remote start works and when it does not.

Thank you for any insight and for answering my and others questions.
 
#62 ·
Regarding your issues starting your vehicle: the starting system is pretty complex and would be very difficult to diagnose remotely. I would suggest working with your local dealer and familiarizing yourself with the conditions listed in your owner's manual with regards to when your remote start will and will not work.
 
#12 · (Edited)
Thanks for coming to this forum again. I've talked to a few of you in person several times and I really appreciate what you guys have to say.

I was wondering why Chrysler has decided to stick with iron blocks when the competition is using aluminum blocks and the LX/LC cars are already considered heavy in comparison. With the '11 Charger (and Challenger I assume) gaining 100 lbs is there anyone at Chrysler considering ways to lighten these already heavy cars?

My '07 Charger SRT8 is down to less than 3500 lbs. so I'd be happy to take the job of "weight reduction czar" at Chrysler if that position ever comes available :mrgreen:
 
#13 ·
Thanks for coming by the forum!:thumbs_u:

I know you can't comment on future products, but are the ideas of "SRT", "Charger" and "AWD" mutually exclusive, only in pairs, is there hope for all three from the factory in this new generation?:modding:
 
#14 ·
Is the 2011 6.4 Hemi based more from the previous 6.1 engine (like the MP 6.4 crate engine) or is it more based from the latest 5.7 Hemi ? In other words, is it a stroked 6.1 or a bored and stroked 5.7 ?

Thanks so much for taking the time to come visit with us and answer our questions..
 
#65 ·
Is the 2011 6.4 Hemi based more from the previous 6.1 engine (like the MP 6.4 crate engine) or is it more based from the latest 5.7 Hemi ? In other words, is it a stroked 6.1 or a bored and stroked 5.7 ?

Thanks so much for taking the time to come visit with us and answer our questions..
The 392 is a combination of new, modified 6.1L, and carry over 6.1L and 5.7L We use what works for us. Most parts are new.
 
#16 ·
Why did the 392 Challenger receive a different front chin spoiler and what added benefit does this do compared to a 2010 SRT8 Challenger chin spoiler? Will a 2010 SRT8 be able to utilize this new part or will the front fascia also have to be replaced?

Thanks a bunch and will always remember the SRT driving experience!
 
#73 ·
Why did the 392 Challenger receive a different front chin spoiler and what added benefit does this do compared to a 2010 SRT8 Challenger chin spoiler? Will a 2010 SRT8 be able to utilize this new part or will the front fascia also have to be replaced?

Thanks a bunch and will always remember the SRT driving experience!
The new front fascia integrated spats into the fascia to give a more pronounced front end. The new part chin spoiler matches profile to the old fascia, but it will not work since the attachments are different location and size (however close)
 
#17 ·
Hello and thank you for taking the time out to do this. I have a 2007 Jeep Grand Cherokee SRT8 and there is a vibration from 60 to 80 mph. The tires have been balanced, and they are the factory runflats. The vehicle has 29000 miles. Is there anything you can suggest to remedy this problem? The vehicle is stock, no additions whatsoever.
 
#74 ·
Hello and thank you for taking the time out to do this. I have a 2007 Jeep Grand Cherokee SRT8 and there is a vibration from 60 to 80 mph. The tires have been balanced, and they are the factory runflats. The vehicle has 29000 miles. Is there anything you can suggest to remedy this problem? The vehicle is stock, no additions whatsoever.
Have you noticed the vibration getting worse over time? If you have had the tires balanced and had the road force variation measured, than we would recommend having a dealership look at it, and possibly do a system balance to the AWD system.
 
#21 ·
hey gang great to have you back here on the LXF!!!
thanks for taking the time to come and share with us again!

first off i have to say it is awesome to see a dual muffler set up for the new cars rather than the suitcase. someone was thinking ahead!
just had two questions;
1) do you think you folks will ever get the green light to produce a factory supercharged srt vehicle?
2) i run royal purple in my motor. i notice a lot more in my catch can than with the mobil. is the purple too thin for our motors from your points of view?

thanks for being here with us and looking forward to some great discussion.
 
#76 ·
hey gang great to have you back here on the LXF!!!
thanks for taking the time to come and share with us again!

first off i have to say it is awesome to see a dual muffler set up for the new cars rather than the suitcase. someone was thinking ahead!
just had two questions;
1) do you think you folks will ever get the green light to produce a factory supercharged srt vehicle?
2) i run royal purple in my motor. i notice a lot more in my catch can than with the mobil. is the purple too thin for our motors from your points of view?

thanks for being here with us and looking forward to some great discussion.
1) We can't talk about future products

2) We have not tested royal purple or catch cans so we can't really tell you much anything about them.
 
#22 · (Edited)
In regard to the use of GPEC controller on the new 2011 + SRT8 Challengers and 2012+ SRT8's, will the NGC series of PCM's ever return to production or is the NGC PCM system dead?


It can't be just a Chrysler US/German thing because GPEC was the brainchild of Chrysler and a couple Japanese firms.
I know the GPEC 3 will run the Phoenix and Tigershark series of engines

The same microprocessor is used in both so why the change from NGC to GPEC?

Some claim the GPEC is the only controller that can run VVT properly is that true?

Or was cost the factor in rewriting the NGC operating system and GPEC was already in the stock bin?
 
#81 ·
In regard to the use of GPEC controller on the new 2011 + SRT8 Challengers and 2012+ SRT8's, will the NGC series of PCM's ever return to production or is the NGC PCM system dead?

It can't be just a Chrysler US/German thing because GPEC was the brainchild of Chrysler and a couple Japanese firms.
I know the GPEC 3 will run the Phoenix and Tigershark series of engines

The same microprocessor is used in both so why the change from NGC to GPEC?

Some claim the GPEC is the only controller that can run VVT properly is that true?

Or was cost the factor in rewriting the NGC operating system and GPEC was already in the stock bin?
The NGC is still in production in Trucks and Jeep products. In general, module technology changes due to increased memory requirements due to feature requirements or regulatory requirements.
 
#23 ·
ok guys, here's an abstract one for you, or to maybe forward on.

where in the (2007 vintage) FCM-CGW is the vehicle's advertised engine displacement stored. for example, a 5.7 car, flashed as a 6.1 in the PCM. it's still recognized as a 5.7 by the star scan and star mobile. the PCM and ABS recognize it as a 6.1 though in their configurations. i don't see it in the FCM configuration, does it read it from the VIN?
 
#87 ·
Due to their respective calibrations, the ABS and PCM communicate to each other via bus message to let each other know the important configuration bits. Additionally, if you can find the 5.7L configuration via a diagnostic tool, that would be the configuration where it would say it's a 6.1L
 
#83 ·
- Will the 392 share interchangeable parts with the current 6.1?
- Will the new Android phone apps work with 2006 300 srt Bluetooth software?

Thanks for making my car J
Here's a quick summary:
PT : 6.1L vs 6.4L is all new - some minor interchangeability misc parts like rocker arms but mostly all new.
Body : Pretty much c/o (except for front fascia attach)
Interior: New seats and seat tracks (can't put '11 seats in '10)
Chassis: New Front/Rear cradles -- Front (new steering / eng mounts, camber), Rear (park brake, susp links)
Electrical : c/o with new alternator and starter (Still CAN based)

As for Android Phone question - not sure
 
#25 ·
Thanks for listening and answering our questions, i have a 2009 charger srt-8 the tranny still upshifts out of first at ant time it wants. Will the new mtcm change that and what are the shift points? Part #on the box is p5155177, part # on the actual controller is pp5155179aa, have not installed this yet because the dealership installed the first one by the insrtuctions and fried it, im now told just to install it at home and run the adaptives, yes or no, thanks again.
 
#91 ·
Thanks for listening and answering our questions, i have a 2009 charger srt-8 the tranny still upshifts out of first at ant time it wants. Will the new mtcm change that and what are the shift points? Part #on the box is p5155177, part # on the actual controller is pp5155179aa, have not installed this yet because the dealership installed the first one by the insrtuctions and fried it, im now told just to install it at home and run the adaptives, yes or no, thanks again.
P5155177 is the kit part number. P5155179 is the part number for the actual controller. The new TCM does have the hold-in-gear feature that will prevent it from upshifting in Autostick mode. The shift points are the same. Sorry to hear your first controller got damaged. The instructions do warn against intializing the controller as that will wipe out the Mopar Programming. See below.

DO NOT USE THE STARSCAN "INITIALIZE EGS - 52/53" FUNCTION AS YOU WOULD WHEN REPLACING A FACTORY TCM. DOING SO WILL CORUPT THE MOPAR PERFORMANCE TCM PROGRAMMING AND WILL RENDER THE MODULE NON FUNCTIONAL.

Most customers should be able to install the part themselves, just be sure to follow all the instructions included with the kit.
 
#26 ·
Hello team SRT, at 55k miles my 300 is as strong as ever and has required very little maintenance and basically zero repairs. Thanks for making such a great car, it's definitely driven like you intended it to be :)

Two questions...

1 - You have to admit the other American manufacturers are doing forced induction, is there a coprorate mandate against superchargers at Chrysler? No profit in it???

2 - Did you guys ever share your thoughts on the bad calipers you got your hands on? Finding bad pistons on the front calipers is still happening. Have you shown them to Brembo, and what was their response???

Keep up the great work!
 
#42 ·
Big thanks to you guys again for taking the time to answer questions for us here! Your efforts are greatly appreciated!!!

I wanted to re-iterate Eric's question from earlier in this thread - corroded front calipers continue to be an issue for quite a few folks - myself included. I've been tracking this issue for a long while and would be extremely interested in knowing if you've been able to make any progress with this. I'd also like to make you an offer: If you let me know where I can send pics (wasn't able to get them in time for this session, sorry), I'd be more than happy to get my car on a lift and get as many pictures of a corroded caliper currently on my car as you'd like. Additionally, I'm going to have to replace this caliper in the near future, and would be more than happy to send the caliper direct to you guys if you tell me where to send it. Alternately, if it would be helpful to have the caliper looked at by a dealership of your choosing (I'm in the Midwest), I'd be happy to do that as well.

The prospect of having to replace the front calipers every year or two is not a fun one, and I'm more than willing to do anything I can do help solve this issue!

Thanks again!

2 - Did you guys ever share your thoughts on the bad calipers you got your hands on? Finding bad pistons on the front calipers is still happening. Have you shown them to Brembo, and what was their response???

Keep up the great work!
 
#27 ·
Thanks for taking the time to be here and answer our questions.

I have a 2009 SRT8/6SPD Challenger that I use as a track toy for drag racing and road racing.

Can you tell us what the 2011 6-spd gear ratios are? I heard that 5th and 6th gear were changed to bring down the speeds and make them more usable but have been unable to find the detailed ratios for each gear.
 
#84 ·
Thanks for taking the time to be here and answer our questions.

I have a 2009 SRT8/6SPD Challenger that I use as a track toy for drag racing and road racing.

Can you tell us what the 2011 6-spd gear ratios are? I heard that 5th and 6th gear were changed to bring down the speeds and make them more usable but have been unable to find the detailed ratios for each gear.
The trans ratios are unchanged for 2011.
 
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