LX Forums Forum banner
Status
Not open for further replies.

SRT Engineers Roundtable: 07/21/10

120K views 146 replies 56 participants last post by  WitchyWndy 
#1 ·
SRT Engineers Round Table Discussion, Part III

Wednesday, July 21st 6pm - 8pm 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 so you can start posting your questions.
 
See less See more
#3 ·
They were still considered "Future Product" this weekend at LX & Beyond in Ohio. I doubt they can say anything other than it exists and it is currently in production. When the OFFICIAL numbers are released I'm sure it will blaze across the forums faster than anything.
 
#4 ·
Is there a way to test a Throttle body to see if the motor is going?
 
#5 ·
Can you shed any light on the theory that line locs may be causing Getrag clucth pack failures, and why?

Thanks,

Ken
 
#6 ·
Have you had a lot of issues with fan motors, I am on my third set and the car is only 3 years old ?
 
#7 · (Edited)
SRT Engineers,
Thanks so much for taking your personal time to have these discussions with us. This type of interaction with the engineering knowledge behind these great cars was a significant contributing factor in my decision to buy a new SRT8 for myself. In the few months we've owned our car we've enjoyed it so much that we've just added another new SRT8 to our garage for my wife.

We are really enjoying our hot rods - Thanks!

Questions

-For the Chassis guys:
Has your testing of the front and rear strut tower braces shown a measurable positive performance result? Any info/metrics you can share with us would be greatly appreciated.

-For the Engine guys:

What is the limiting factor for the 6100rpm redline on the 6.1? Valve springs? pistons? heads??

Thanks again!
 
#39 ·
SRT Engineers,
Thanks so much for taking your personal time to have these discussions with us. This type of interaction with the engineering knowledge behind these great cars was a significant contributing factor in my decision to buy a new SRT8 for myself. In the few months we've owned our car we've enjoyed it so much that we've just added another new SRT8 to our garage for my wife.

We are really enjoying our hot rods - Thanks!

Questions

-For the Chassis guys:
Has your testing of the front and rear strut tower braces shown a measurable positive performance result? Any info/metrics you can share with us would be greatly appreciated.

-For the Engine guys:
What is the limiting factor for the 6100rpm redline on the 6.1? Valve springs? pistons? heads??

Thanks again!
The valvetrain is the limit on the engine but the A/T trans shift speed limit is right there too.
 
#8 ·
Lots of 5.7 guys have added the 6.1 oil pump to their 5.7 engine. Some have issues with MDS since pressure is higher, any other issues to be concerned about as it was designed for the 6.1 oiling circuit and not the 5.7?
 
#9 ·
Can you shed some light on the diagonal braking that the SRT engineers mentioned at LX ? Beyond and it's impact on the Getrag clutches when using a line-loc. Thank you
 
#10 ·
Spark plugs.
Is there a recommended mileage for changing plugs in our vehicles for day to day, spirited driving?
Combustion/injector cleaning.
Your recommended maintenance schedule for combustion cleaning and as well as fuel injectors with again day to day spirited driving habits.

Note of thanks.
For designing the best vehicle I have ever driven lifetime.

 
#62 ·
Your SRT8 spark plugs are Platinum tipped and are good to well past 100K miles. If you are driving "spirited" they should be cleaning themselves continuously. For injectors (and valves for that matter) using good quality premium fuel will give you the detergents and additives necessary to keep those components clean.
 
#11 ·
Hypothetically,if you guys had a LX and wanted a stock cat back exhaust what would you do to modify it, if anything to support say 650-700hp? I know what Pauls answer is,but I wondered if there were any other opinions on increasing the flow or if it is even needed.
 
#12 · (Edited)
A lot of folks on the forum have had a problem with engine stalling. For me on three separate occasions the car (2009 Challenger SRT8) has stalled when slowing down and preparing to make a turn. It happened twice with my 6.1L engine and once with the 426. Given it has happened with the stock and stroker engines I don't think it is the engine. Is it a potential problem with how the fuel system/tank is designed ? Would like any insight on where to look for the problem and how to solve the issue?
 
#13 ·
Why is the TCM programming still such a mystery to aftermarket companies. Seems like the PCM tuning has either been released or at least decoded allowing us to reap some good performance gains. Why not release the TCM tuning codes to allow us to keep up with the competition (which is getting very stiff).

Lots of these cars with aftermarket parts are making power past 6400 rpms and my buddy with an '06 300 SRT8 (without the TCM flash) is able to paddle hold the shift at times to 7000 rpms without a problem. Some of us here are big boys and are willing risk popping a motor (on our dime).
 
#53 ·
Why is the TCM programming still such a mystery to aftermarket companies. Seems like the PCM tuning has either been released or at least decoded allowing us to reap some good performance gains. Why not release the TCM tuning codes to allow us to keep up with the competition (which is getting very stiff).

Lots of these cars with aftermarket parts are making power past 6400 rpms and my buddy with an '06 300 SRT8 (without the TCM flash) is able to paddle hold the shift at times to 7000 rpms without a problem. Some of us here are big boys and are willing risk popping a motor (on our dime).
Sorry, for right now there are no plans to open up the cals for modification. Altough we know many of you are capable ofmaking the right kinds of mods remember the trans is not rated for anything above the production performance output.
 
#15 ·
Thank you for electing to attend these Q&A's; we consider them of great value to us.

Please forgive the reference to a non-SRT part in this comparison; it has been suggested that the new 2009 composite intake manifold is very similar to the 6.1 aluminum intake in rate-of-flow, runner length, and therefore power band. Flow results have the 2009 composite unit within a few CFM of the existing SRT intake manifold.

Can you kindly confirm or deny please they are pretty close in actual configuration. The idea being the composite version offers less mass and a lot less heatsoak...
 
#73 ·
OK, you must be talking about the Eagle composite intake manifold as a comparison to the 6.1L manifold. There are several Eagle intakes (for different applications) with different features. Generally we would not recommend swapping the intakes. If you were really intent on improving the intake flow on the 6.1L a port and polish of the aluminum runners on the 6.1L would be a better way to go.
 
#16 ·
It's noteworthy the number of camshaft chain tensioner backplate assemblies developing stress cracks (between the lower mounting bolt and the slot used to drip-lubricate the camshaft chain) on both the 6.1 and 5.7, to the point in some cases where the bottom section has separated.

Beech-marking is present at the fracture face indicating an incremental failure over time, along with other signs that point directly to the leaf spring structure(s) themselves being the root cause (failed first - allowing the chain to whip, thereby stressing the tensioner backplate). The camshaft chain tensioner assembly on the 6.1 has an extra leaf spring (when compared to the 5.7 unit). Can you explain why this is please.
 
#17 · (Edited)
It continues to be bandied about that the 6.1 (and to a lesser degree the 5.7) has an excessive PCV oil vapor ingestion issue that is the root-cause for pulling timing (by-way of the knock sensors - supposedly reacting to octane level degradation because of significant oil consumption/oxidation under normal operating conditions. The cure recommnded by the vendors for this ailment is purchasing/installing a catchcan.

During (factory) engine assembly, are the knock sensors raw voltage O/P tested, or even monitored from engine-to-engine? It appears the amount of timing being pulled due to knock sensor activation (real or perceived) varies from platform to platform. Is this normal (it's understood that fuel quality, engine load, atmospheric conditions, etc play a part)?
 
#58 ·
It continues to be bandied about that the 6.1 (and to a lesser degree the 5.7) has an excessive PCV oil vapor ingestion issue that is the root-cause for pulling timing (by-way of the knock sensors - supposedly reacting to octane level degradation because of significant oil consumption/oxidation under normal operating conditions. The cure recommnded by the vendors for this ailment is purchasing/installing a catchcan.

During (factory) engine assembly, are the knock sensors raw voltage O/P tested, or even monitored from engine-to-engine? It appears the amount of timing being pulled due to knock sensor activation (real or perceived) varies from platform to platform. Is this normal (it's understood that fuel quality, engine load, atmospheric conditions, etc play a part)?
Both the 5.7L and 6.1L engines meet all corporate requirements for PCV performance. However, as we have mentioned in previous chats, installing a catch can shouldn't harm anything.

During end of line testing, output from the knock sensor is verified to be present. Comparing the amount of knock retard between vehicles can be deceiving. As you mentioned there are many factors that affect knock limit. Unless the conditions of your test subjects are identical (highly unlikely), the amount of knock retard can vary.
 
#18 · (Edited by Moderator)
Hello & Thank you for your time

I own a 2009 300C AWD, I'm trying to build an AWD SRT8. The new Borg Warner front axle disconect system is both AWD & or RWD!! I would like to drop in a new 6.4 392 VVT MDS when it comes out. Will the Borg Warner transfer case handle the power, can I change the 3.07 ratio to 3.55 or 3.73 LSD with a transfer case performance upgrade & what else would I have to consider to make my 2009 300C AWD, a 300C AWD SRT8?

Thank you very much
 
#56 ·
Hello & Thank you for your time

I own a 2009 300C AWD, I'm trying to build an AWD SRT8. The new Borg Warner front axle disconect system is both AWD & or RWD!! I would like to drop in a new 6.4 392 VVT MDS when it comes out. Will the Borg Warner transfer case handle the power, can I change the 3.07 ratio to 3.55 or 3.73 LSD with a transfer case performance upgrade & what else would I have to consider to make my 2009 300C AWD, a 300C AWD SRT8?

Thank you very much

Mods List to Date:

Mopar Cold Air Intake, Billet Aluminum Fuel Rails w/ Fuel Pressure Gauge for the 392 Crate Motor, 6.1 SRT8 Injectors & Spark Plugs, Engine Strut Brace & Rear Sway Bar
Custom Borla Cat Back #140112, KW Varient 2 Coilovers, Jet 180 Thermostat, MSD Hemi Blaster Coils, StopTech Cross Drilled Rotors fr/rr, Hawk Performance Pads Ceramic up front & HP Plus rear, SLP Line Lock, Functional Fiberglass Ram Air Hood, Vossen VVS 075 Wheels 20x9 fr/rr, Nitto Invo 245/45/ZR20 Ultra High Performance Summer Tires ft/rr,
Mopar SRT8 Illuminated Door Sills (Scuff Plates), SRT8 Trunk Lip Spoiler, & SRT8 Badges
SRT8 Pedals & Custom SRT8 Cluster Gauges

Future mods List:

Kooks Long Tube Headers with High Flow Cats, or Borla XR-1 Long Tube Headers, CNC Aluminum Heads & Cam for the Eagle Engine, 90mm Throtle Body, 5.7 Eagle 392 Stroker Kit, or a New 6.4L 392ci VVT MDS Hemi, STS Rear Mount Twin Turbo or SMS Super Charger, 1000 Hp Half Shafts front & rear, 1000 Hp Drive Shaft, 1000 HP Nag1 Transmission, 1000 HP Borg Warner Front Transfer Case Upgrade & 3:55 or 3:73 rear end gears to match the Transfer Case, Brembo GT Drilled Rotors w/8 Piston fr & 6 piston rr Aluminium Calipers w/ High Performance Pads & w/ High Performance Metal Braided Tubes, Vossen VVS 075 20x10.5 in. w/ Nitto NT05R 285/40/ZR20 rears, 4000 Stall Converter, Police Transmission & Engine Oil Cooler, B5 Blue Pearl SRT8 Challenger front Seats, AWD Custom Tune, Predator.
The BW T-case is normally RWD but engages the front when needed. So yes it is kinda both AWD and RWD.
 
#19 · (Edited)
Hey guys and gals..thanks for having these disscussions...I have posted this before and wondering if this is going to take place per earlier chats..
Quote:
Quote:
http://www.chargerforums.com/forums/showpost.php?p=1520964&postcount=173
Originally Posted by Joeyclutch
I've been having a problem with a front end noise. Its been to the dealership several times and nothing has been resolved. They have replaced the steering rack, control arms, the bushings, struts and bracketts. I only drive this car abhout 4000 miles a year so I feel that this should not ben happening. The regional service rep said that this "noise" is a characteristic of the SRT vehicles from 2006-2007. I have driven in other SRT vehicles and did not notice this noise at all. Obviously they thought there was a problem with my car or they would not have switched out all of those parts. I even went so far as to look into the Lemon Law but unfortunately I was passed the alloted time. I dont think this is fair and need advice. Thank you.

For 2008, there was a check valve change to the shocks which helps this noise. They are retuned for better ride as well, so we suggest replacing all 4 if you want to go this route. The source of the remaining noise is the front upper strut mount in rebound events. We are working on a design change to help the issue, but it will be some time before we will have something out. Thanks to these webchats, we are able to convince management we need to keep working on it.
Is there a replacement strut mount available yet? If so, is there a way to differentiate the new design vs. old to make sure I am getting the new one?

Is there a way to differentiate (visually) the revised dampers from the old ones?

Thank you

I was just wanting a time line that I could possibly get the redesigned dampers..The dealership has replaced both struts and several other parts, but when showing them the chat answer from before..they are also waiting the redesigned part.....Any thoughts on this

And thanks in advance..
Ralph
 
#37 ·
2007 Magnum SRT8

Does the TC lockup in all gears except 1st? I get a bog under light throttle in 2 and 3rd gears and I'm assuming its the TC locking up. Is there something else I may be missing that is causing this bog? Under WOT, it pulls as it should.
And second, why does the 6.1 have such a major issue with Knock retard? Even stock alot of them knock on 93 octane, and modded, forget it, its horrible. I've never seen a naturally aspirated motor knock the way the late model Hemis do.
I have the same questions!
 
#22 ·
have you got a fix for the coolant overflow on teh 09 GC SRT? it is a PITA to keep clean and I have to add all teh time...

Also,

at what point does the oil light on teh 6.1 come on? I have seen with my own eyes that a 6.1 was driven with only 2 qts in it and the oil light or low oil or check oil inticator did not come on...
kinda stupid if the car is equipped with a check oil indicator and it does not illuminate untill after catastrophic damage..
 
#71 ·
have you got a fix for the coolant overflow on teh 09 GC SRT? it is a PITA to keep clean and I have to add all teh time...

Also,

at what point does the oil light on teh 6.1 come on? I have seen with my own eyes that a 6.1 was driven with only 2 qts in it and the oil light or low oil or check oil inticator did not come on...
kinda stupid if the car is equipped with a check oil indicator and it does not illuminate untill after catastrophic damage..
Since the coolant overflow bottle was common on all WK's, the cost to change the bottle for just SRT could not be justified.

As for the oil light, it only comes on when there is a drop in oil pressure and not oil level. Would this be something that you would want?
 
#23 ·
Why can't we have an option from the factory to have a Dana 60 in our cars? I know it would be an expensive option but thats our choice, please consider! I have a 2008 twin turbo challenger and we just installed a Dana 60 in it and it looks great and hoping for some 9.2's here in the near future. I was at LX and Beyond but we didn't get to talk to each other. Thank you for your time!
 
#24 ·
When out on a road course my Traction Control Light comes on by itself and stays on until the session is over. Can you explain why it does that? I have heard it does that because the brakes are hot and the computer doesn't want to keep applying the brakes so much. Any truth to that? This is happening on a 2006 GC SRT8.
 
#26 ·
I`m havn sum issues with my 6.1 after moving and was wanting to know if you guys can help me. I moved from S tx to S Va about a week ago. Since being here the car is kinda sluggish till it hits 3-4K rpm`s and then it takes off like a bat outta hell? Also, when i`m running the car hard in 2nd gear it will hesitate like its missing or havivg fuel issues right befor it does the auto shift....did it once today so i ran the piss out of it and it has not happened again. I have reset the addaptives once by disconnecting the battery, but its still happening? I do not have a tuner and have never had one and i only have bolt on mods like a CAI and exhuast. Any ideas would be much appreciated as this is drivn me CRAZY! I have no engine codes what so ever
 
#75 ·
Since we're all about performance we suggest moving back to Texas or keeping the RPMs above 3,000 :racing:Seriously, there is no reason your car should run any different in your new location.

The hesitation before the shift was probably the rev limiter. The SRT TCU programming has a smaller RPM window than a 5.7L to execute a shift. If the shift takes longer than expected or the rate of RPM increases during the shift, it is possible to get a torque reduction from the rev limiter before the shift can complete.
 
#27 ·
I have one question and it will probably be considered a "Future Product" question but...

Is the Viper Dead? simple yes or no is all I need.

Thanks for your support on our site and at LX and Beyond. We really appreciate your team taking the time out of your busy schedule to speak with us enthusiasts.

Greg
 
Status
Not open for further replies.
You have insufficient privileges to reply here.
Top