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SRT Engineers Roundtable: 12/02/09

113K views 179 replies 65 participants last post by  SRTEngineers 
#1 ·
SRT Engineers Round Table Discussion, Part II

Wednesday, December 2nd 6pm - 8pm

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 so you can start posting your questions.
 
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#27 · (Edited)
Ok now that we have a few guys doing the standing mile runs and are getting close to the 200 mph mark I have a few areo questions on the LX line of cars.

At up to what speeds have you tested the cars ( Track and Wind tunnel )

What are the front and rear down force numbers ?

On the factory SRT suspension what is the corner weight bias ? w/o driver

How much drag do you see from the rear fascia ? Is the under pan there to reduce drag/turbulence ? or to just keep it from flapping around at speeds ?

The 09 Getrag center section, is it used any any other cars that you know of ? And are rebuild kits going to be made available as there are a few that are peg legging already.

-Robert
 
#91 ·
Ok now that we have a few guys doing the standing mile runs and are getting close to the 200 mph mark I have a few areo questions on the LX line of cars.

At up to what speeds have you tested the cars ( Track and Wind tunnel )

What are the front and rear down force numbers ?

On the factory SRT suspension what is the corner weight bias ? w/o driver

How much drag do you see from the rear fascia ? Is the under pan there to reduce drag/turbulence ? or to just keep it from flapping around at speeds ?

The 09 Getrag center section, is it used any any other cars that you know of ? And are rebuild kits going to be made available as there are a few that are peg legging already.

-Robert
The fastest I have gotten the '09 Challenger SRT8 up to is 181 mph (rev limiter in 5th, manual trans) with a tailwind on our test oval. Our full scale wind tunnel goes up to 140 mph. There is not much reynolds effect on the Challenger, so the aero numbers stay proportional with speed.

See previous post for aero numbers.

Corner weights are decent and depend on options. Who cares what it is without the driver? What it is with the driver is what matters.

There is very little drag with the rear fascia. The rear tire tub and resonators fill the hole nicely.

Cluch packs are common to the new CTS-V. Ring and pinion are not.
 
#29 ·
My SRT8 Charger has been a blast for the past couple years. I've enjoyed the whole experience and want to thank you guys for the input you've had.

I notice MOPAR is making an aluminum block available now. Was cost the only consideration in making the 5.7 and 6.1 blocks out of iron?

This may have been addressed before but it has been noticed that some factory x-pipes are closed off and only appear to cross gases from each pipe. Was this intentional? If so, why?
 
#83 ·
My SRT8 Charger has been a blast for the past couple years. I've enjoyed the whole experience and want to thank you guys for the input you've had.

I notice MOPAR is making an aluminum block available now. Was cost the only consideration in making the 5.7 and 6.1 blocks out of iron?

This may have been addressed before but it has been noticed that some factory x-pipes are closed off and only appear to cross gases from each pipe. Was this intentional? If so, why?
Cost is the major issue behind the iron vs. alum.

The X-pipe closed vs. open was actually done for sound quality. We wanted a more aggressive exhaust note on the Charger vs. the 300C so the Chargers got the closed x-pipe.
 
#30 ·
Mopar Performance has Coil Overs, Fuel Rails, Cat-Back, and CAI for the 6.1.....

Are there any plans to release more Mopar Performance Parts for the LX SRT?
 
#31 ·
Thanks for coming.

Challenger SRT8 cars are criticized for numb steering, we are told a certain amount of body roll was dialed in for retro handling. Really?

Is a 2009 ChargerSRT8 suspension different, how do we Challenger owners "dial in" a better handling ride and what can be done about numb steering feel?

Thanks again John.
 
#88 ·
Thanks for coming.

Challenger SRT8 cars are criticized for numb steering, we are told a certain amount of body roll was dialed in for retro handling. Really?

Is a 2009 ChargerSRT8 suspension different, how do we Challenger owners "dial in" a better handling ride and what can be done about numb steering feel?

Thanks again John.
All the L series SRT's have the same steering systems, with unique suspension tunes to give them unique personalities. The 2009's do have a caster change and a slight retune to the suspension.
 
#32 ·
I was at Talladega this fall for the race and witnessed the SRT experience with the drifting. It was freaking amazing!!!

Two questions:
1. Do you know what special mods were done to these cars, if any?

2. Please see picture below and I'm pretty sure those rims aren't stock Challenger SRT rims and maybe Magnum SRT rims. Do you know why this might have been done?

Thank you!

 
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#35 ·
we truly appreciate you taking the time out to answer our questions and chat with us about these incredible cars you guys make.

Thank you!
ditto!!!!!
 
#36 · (Edited)
SRT Engineers - thanks for doing this chat session for us! Couple of questions please:

1) For the new Challenger, lowering springs are a common and popular modification. Currently Mopar offers SRT8 springs for the Challenger R/T, but there is nothing for the SRT8. Are there any plans to offer offer Mopar lowering or higher performance springs for the Challenger SRT8?

2) Are there any plans to offer Mopar supercharger kits for the 5.7 or 6.1 Hemi?

3) The 6.1 L Hemi has been built to be considerably stronger, with forged crank and strengthened block, etc. Can you tell us what "limit testing" has been done to see how much horsepower this configuration will support without the use of more forged internals? You guys are all motorheads just like us, so I'm sure you've tested these engines with varying levels of boost. Wondering what level will remain safe before getting the engine's capability too close to the safe upper limit. If I had to guess I'd say 10PSI or under is safe, but would love confirmation.
 
#94 ·
SRT Engineers - thanks for doing this chat session for us! Couple of questions please:

1) For the new Challenger, lowering springs are a common and popular modification. Currently Mopar offers SRT8 springs for the Challenger R/T, but there is nothing for the SRT8. Are there any plans to offer offer Mopar lowering or higher performance springs for the Challenger SRT8?

2) Are there any plans to offer Mopar supercharger kits for the 5.7 or 6.1 Hemi?

3) The 6.1 L Hemi has been built to be considerably stronger, with forged crank and strengthened block, etc. Can you tell us what "limit testing" has been done to see how much horsepower this configuration will support without the use of more forged internals? You guys are all motorheads just like us, so I'm sure you've tested these engines with varying levels of boost. Wondering what level will remain safe before getting the engine's capability too close to the safe upper limit. If I had to guess I'd say 10PSI or under is safe, but would love confirmation.
1) PN P5155436 lowering springs are available at your dealer today.

2) Well, we never say never but soon.

3) As engineers we work hard to optimize all of the components. So the answer to your question would be there's risk inherent in any increase in boost for your engine. How much your willing to except would be up to you.
 
#37 ·
the Mopar TCM for the LX platform is listed for 2005-06 vehicles only. there are a few people who have tried using it on later models and succeeded. Mopar's tech hotline states it is not applicable for later model years. they mentioned a new TCM coming.

which is accurate? should it work on all 05+ LX's or not. if not, is there a part number for the new TCM?
 
#38 ·
Just to follow on....

It also states that it is for not for the 6.1L. Why is that?
 
#46 ·
What is the thickness of the upper ringland on an 09 rt challenger. Thanks for the greatest car built by Man(and woman)
 
#49 ·
I have a 2010 Challenger SRT8 6spd and I despise the skip shift. I know you can`t recommend disabling the skip shift, but there is a kit out there that emulates the resistance of the solenoid to avoid tripping the MIL due to that, but can you confirm the `10 models will trip the MIL because the ecm knows the transmission is not in 4th?
 
#50 ·
Staggered f to r

I am trying to stagger the wheel/tire diameter difference between front and rear.
What is the largest percent difference I can achieve before the ABS or other electronic control device will be affected.

Can these controls be modified or eliminated?


Love my RT 100k and doing a Big Daddy redo!
 
#99 ·
I am trying to stagger the wheel/tire diameter difference between front and rear.
What is the largest percent difference I can achieve before the ABS or other electronic control device will be affected.

Can these controls be modified or eliminated?

Love my RT 100k and doing a Big Daddy redo!
5% diameter difference.

They can't be modified. If you eliminiate it, you eliminate ABS. Unless you built tonewheels with more teeth on the front than rear...
 
#53 ·
I have an 08 GCSRT8, and I'm having problems on wet roads. Until yesterday every once in awhile, from a standing start, the vehicle will loose traction and all the power seems to go to one wheel ( rear Wheel ) quite an expearance to say the least. Yesterday it started doing something new, unless you barley gave it any gas and just putt putted at start off, the ESP would engage and the vehicle would get a little unstable but not like before when it would just plain get out of control. Prior to this the vehicle was as stable on wet roads as dry roads. Any ideas the Tech. who is great with SRTs, can't find anything. Any Ideas?



Thank You
Jack
 
#114 ·
I have an 08 GCSRT8, and I'm having problems on wet roads. Until yesterday every once in awhile, from a standing start, the vehicle will loose traction and all the power seems to go to one wheel ( rear Wheel ) quite an expearance to say the least. Yesterday it started doing something new, unless you barley gave it any gas and just putt putted at start off, the ESP would engage and the vehicle would get a little unstable but not like before when it would just plain get out of control. Prior to this the vehicle was as stable on wet roads as dry roads. Any ideas the Tech. who is great with SRTs, can't find anything. Any Ideas?

Thank You
Jack
It seems like you may be having a wheel sensor dropping out or your transfer case is not engaging correctly.

When the system is working correctly as soon as the system detects rear wheel spin the AWD system starts to send power to the front wheels, and the ESP system pulls power until the tires catch up.... withone wheel spin, the BLD system starts pulsing the brakes to optimize traction.

Next time, see what the vehicle does with ESP partial off, which would preload torque to the front axle. My bet is that you have a bad wheel speed sensor.
 
#108 ·
Hello team SRT!

I would like to know your opinion on this...

We build a lot of supercharged SRT-8's and they all seem have the same issue.

When you apply part throttle, as soon as MAP goes to 0, the throttle fully opens.

Any ideas?
Good to hear you're a serious enthusiast but we didn't engineer the car with forced induction. It's really hard to say what the engine and sensors are doing. Kinda like telling a mechanic "it goes clacker clacker when I turn left".
 
#56 ·
Thank you for taking out time in your obviously busy schedules. Since you already answered my question about the upcoming production 6.4L, I'll ask a couple about the 6.1L. Having both the 5.7L and 6.1L apart at one time or another. Why was the 6.1L never equipped with MDS??? The provisions are there in the block, so why not??? I know you'll probably say that the 6.1L is all about performance, not economy, but we all have the ability through the way of aftermarket programmers to shut the MDS off, so why not??? Also, when the 5.7L was updated with VCT, why wasn't the 6.1L as well??? It would have opened up the performance of the 6.1L, and been MORE competitive with the Camaro SS's 6.2L, possibly out performing it.

On a final note, I would hope that the 6.4L definetely has VCT, and ALLOT more power than what has been projected to be able to compete with the competition.

Thank you again.
 
#97 ·
Thank you for taking out time in your obviously busy schedules. Since you already answered my question about the upcoming production 6.4L, I'll ask a couple about the 6.1L. Having both the 5.7L and 6.1L apart at one time or another. Why was the 6.1L never equipped with MDS??? The provisions are there in the block, so why not??? I know you'll probably say that the 6.1L is all about performance, not economy, but we all have the ability through the way of aftermarket programmers to shut the MDS off, so why not??? Also, when the 5.7L was updated with VCT, why wasn't the 6.1L as well??? It would have opened up the performance of the 6.1L, and been MORE competitive with the Camaro SS's 6.2L, possibly out performing it.

On a final note, I would hope that the 6.4L definetely has VCT, and ALLOT more power than what has been projected to be able to compete with the competition.

Thank you again.
You make a lot of good points.
 
#58 · (Edited)
As a very loyal SRT fan owning 1-06 SRT8 Magnum, 1-08 SRT8 Magnum(11 miles on it), 1-08 SRT8 Jeep, 1-2005 VIPER COMP COUPE (#007), and 1-2008 SRT10 Viper. I can only say, THANK YOU. You keep building them and I will keep buying them. Tell Erich H. his 2006 One Lap Magnum buddy said hello. I listen to him when Erich said keep these cars, they will be worth big $ in 20+ years. Mine aren't going anywhere.

My questions are these, Can the 08 Magnum front end be put on an 06 without TOO MUCH trouble? Is it worth the effort?
 
#70 ·
As a very loyal SRT fan owning 1-06 SRT8 Magnum, 1-08 SRT8 Magnum(11 miles on it), 1-08 SRT8 Jeep, 1-2005 VIPER COMP COUPE (#007), and 1-2008 SRT10 Viper. I can only say, THANK YOU. You keep building them and I will keep buying them. Tell Erich H. his 2006 One Lap Magnum buddy said hello. I listen to him when Erich said keep these cars, they will be worth big $ in 20+ years. Mine aren't going anywhere.

My questions are these, Can the 08 Magnum front end be put on an 06 without TOO MUCH trouble? Is it worth the effort?
You should start a separate thread about swapping front ends. I'm sure someone on here will help you out with an answer. ..not really an SRT Engineer question.. :doh:
 
#61 · (Edited)
I understand that the powers to be will not let you guys comment on future products like the 6.4L that coming out. I will say this and hope it reverberates back to the powers that be......if the 6.4L does not have atleast 500 HP and forged internals for FI applications i really dont know why SRT would waste there time. We...Mopar heads need a car that can compete with the competition thats stock. IMO 500HP NA would be ideal with no VVT. The only way mopar will get me to buy another SRT would be with these specs and nothing less. I will say that my 08 SRT has been the best car i`v ever owned for all around performance, looks, and room.......i just want more power without spending 20K at a mod shop.
 
#62 ·
Is there a way to reset the ECU / PCM to the original factory settings, pre April 2006? It appears that the many times that Chrysler has flashed the ECU on the SRT8 the software has dumbed down the performance, taken away the slap-stick functionality and removed the slippage quotient of the rear end and added an adapttive mode.
 
#68 ·
Coolant Gunk 2007 Magnum SRT

I am having trouble getting my local dealer to perform the RRT #07-026 for cloudy coolant with chunks. Service writer says my vin does not apply to this RRT. But this Magnum SRT8 is 2007 with very early build date Sept 06. I had gunky cool very early on complete with the ammonia smell. So before this RRT was even issued I flushed the coolant myself after chatting with you guys during another SRT chat. And basically the gunk is back.

After the the RRT was issued I decided to wait to see if the problem came back and it did. I think it is possible my vin was not included in the RRT because my car was not SOLD it was a prize for the Autorox Car Show. I tired called Chrysler customer service but I wasn't really able to make any progress there. Can you guys help me cut through some red tape? I think one of you guys knows the service manager at my local dealship.

Craig Marr at Chuck Patterson in Chico,CA

I really want to get the flush and coolant tank replaced, it has lots of residue coating the inside and floaters still.

Thanks Chris Teasdale

my vin: 2D8GV77347H609110
 
#73 ·
Why did the Superbee get axed from production ?
 
#75 ·
Maybe this isnt the place for this question-BUT has been floating around the forums for awhile.
How IS IT that a few early model road and tracks and daytona's came from the factory with the 350mm [police package] rear rotors instead of the 320mm? WAS THIS A DEALER SHIP ORDER / A OPTION/ or just sliped out of the factory due to parts unavailable at the plant??
06 daytona mango #0666 has 350mm rotors on the rears from the factory with no mention of it on the window sticker which i found in the glove box
 
#85 ·
Did you come up with any options for the rear supension for drag raceing to help the cars launch like on the 60's cars where u had the pinion snuber and the ss springs with the extra leaves on the front half of the springs and maby som more room in the fender wells for som bigger slicks also the ability to use 15 inch wheels so we can use the big slicks.
 
#123 ·
Did you come up with any options for the rear supension for drag raceing to help the cars launch like on the 60's cars where u had the pinion snuber and the ss springs with the extra leaves on the front half of the springs and maby som more room in the fender wells for som bigger slicks also the ability to use 15 inch wheels so we can use the big slicks.
Currently some rear axle options are being investigated, both for street and strip. At the moment, nothing to announce, but stay tuned in early 2010.
 
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