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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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#4 ·
Do not know if this was ever asked but why not have the "ram air" ducting go to airbox instead of over exhaust? I see slight benefit to current design but would like to know why y'all went that route instead of traditional to intake route?
 
#44 ·
It would have been a big tear up to the induction system which is rather expensive to tool. Also and probably the bigger reason is there is so little room to route between the hood scoop, throttle and where a airbox would have to be place the higher restriction would overcome any gains in ram air.
 
#7 ·
How many many engineers work full time for the SRT team?

Any that are "just" mechanics?

Have you had any new people brought into the division by Fiat, not just a new hire but a Fiat guy?


Sorry if these have been asked before but the last few sessions have been on short notice and I missed them.


Oh and thanks for the work you guys do. I love my SRT8.
 
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#42 ·
Our group has a lot of wonderful, smart, FULL TIME engineers...right now our group is at about 60 SRT engineers.

We do have a group of also wonderful, team player mechanics that work on our SRT products.

SRT does not have any new FIAT employees in our group yet.

Glad to hear you love your SRT.

How many many engineers work full time for the SRT team?

Any that are "just" mechanics?

Have you had any new people brought into the division by Fiat, not just a new hire but a Fiat guy?

Sorry if these have been asked before but the last few sessions have been on short notice and I missed them.

Oh and thanks for the work you guys do. I love my SRT8.
 
#8 · (Edited)
On an 08MSRT the intake track from the airbox to the throttle body, where/what are the restrictions, in order from most to least?

The temp readings in Diagnostic EVIC mode where one is over the other, where are their readings taken from (sensor locations)? It seems the lower one in EVIC that varies is from the sensor in the intake tube in front of the throttle body, but the upper one in EVIC that remains constant where is that located??

Also what temp. thermostat would yield the best results for A. street, B. street and strip, and C. strip only (I live in the Atlanta area)?

Thanks
Steve
 
#48 ·
The biggest restriction in an L-Body Intake system is the 90 degree Clean Air Duct. Its very efficient, don't get us wrong, but improvements have been made and can be seen on the Eagle L bodies now. The second restriction is the 80mm throttle. Air Charge Temperature is read in the Clean Air Duct in front of the throttle and Ambient Temp is read from the bumper beam (i believe). Air Charge Temp is going to move around much more depending on how fast the car is moving and/or how long the car has soaked.....Ambient should obviously be releatively constant unless you travel from the Sahara to the Frozen Tundra in less then a day. Stock Thermostats work great in Atlanta....and everywhere else!

On an 08MSRT the intake track from the airbox to the throttle body, where/what are the restrictions, in order from most to least?

The temp readings in Diagnostic EVIC mode where one is over the other, where are their readings taken from (sensor locations)? It seems the lower one in EVIC that varies is from the sensor in the intake tube in front of the throttle body, but the upper one in EVIC that remains constant where is that located??

Also what temp. thermostat would yield the best results for A. street, B. street and strip, and C. strip only (I live in the Atlanta area)?

Thanks
Steve
 
#9 ·
Can you please release for sale the Viper engine conversion kit that you installed on the Challenger you brought to Ohio. You guys put in all that hard work. According to your team, everything worked on the car and the motor was seamlessly integrated into the CANBUS system. PLEASE SELL IT TO US. WE WILL PAY FOR IT.
 
#51 ·
Can you please release for sale the Viper engine conversion kit that you installed on the Challenger you brought to Ohio. You guys put in all that hard work. According to your team, everything worked on the car and the motor was seamlessly integrated into the CANBUS system. PLEASE SELL IT TO US. WE WILL PAY FOR IT.

We haven't given up yet. What did you have in mind? Just engine or all of the bits and pieces?
 
#11 · (Edited)
Before production started, I had read that the stick-shift Challengers would get stiffer motor mounts. Do they have stiffer motor mounts and if so is it a different design or just stiffer rubber?

Many of us have swapped in the 09 Getrag LSD rear into our pre-09 models. Most of us with the Getrag experience gear whine at light throttle at 50-55 MPH. Would changing to a heavier gear oil have any negative effect on the Getrag's functioning? I know the 215mm diffs took 75-140 gear oil, but the Getrag is 75-90. I assume the change was made to aid in MPGs, no?

Thanks for the great vehicles and keep up the good work!!!!
 
#81 ·
Before production started, I had read that the stick-shift Challengers would get stiffer motor mounts. Do they have stiffer motor mounts and if so is it a different design or just stiffer rubber?

Many of us have swapped in the 09 Getrag LSD rear into our pre-09 models. Most of us with the Getrag experience gear whine at light throttle at 50-55 MPH. Would changing to a heavier gear oil have any negative effect on the Getrag's functioning? I know the 215mm diffs took 75-140 gear oil, but the Getrag is 75-90. I assume the change was made to aid in MPGs, no?

Thanks for the great vehicles and keep up the good work!!!!
The stick shift Challengers have totally different mounts than the autos. The autos have hydro mounts and the manuals have constrained rubber mounts. The reason for the change is to keep them alive with the larger spike loads that come with a stick shift. The SRT manuals are slightly different that the R/T. They have less travel before they snub to the housing for lower less enigne movement.

We haven't used the 75W-140 gear oil in the Getrag diff. The higher viscosity certainly couldn't hurt with gear noise, but I wouldn't expect much of a change. The risks are seal life and clutch chatter. No way to tell without testing it. The clutch pack will still need friction modifier added to it. Good luck if you want to try, but I can't say I'd recommend it.
 
#12 ·
2008 Challenger 500

With a lot of SRT's running around in a boosted state via superchargers or turbos, part throttle boost isn't recognized by the ECM. This leads to lean (14.7) air fuel ratios in part throttle boost situations. Since the SRT4 will handle fuel management under a wider range of throttle positions and boost conditions it has been demonstrated that your team can make things work in these situations. What is the best option to get our forced induction SRT8's to overcome this shortfall and allow us to be competitive with the factory supercharged cars of other manufacture? I'm sure the ECM code is locked up pretty tight, but would you please throw us a bone?

Thanks for your great products and support!!!!
 
#63 ·
Your right, our Turbo cars (Neon and Caliber SRT4's) are capable of part-throttle or pre-boost. They were capable because we wrote the software allowing that type of control. Unfortunately, your SRT8's are not run with the same controllers as the previous cars and therefore do not have the capability of controlling boost in less than a WOT condition. Could we do it....yes....just need the right product and some new software. Sorry, but AEM FICs and Diablosport is all you have on this one.

2008 Challenger 500

With a lot of SRT's running around in a boosted state via superchargers or turbos, part throttle boost isn't recognized by the ECM. This leads to lean (14.7) air fuel ratios in part throttle boost situations. Since the SRT4 will handle fuel management under a wider range of throttle positions and boost conditions it has been demonstrated that your team can make things work in these situations. What is the best option to get our forced induction SRT8's to overcome this shortfall and allow us to be competitive with the factory supercharged cars of other manufacture? I'm sure the ECM code is locked up pretty tight, but would you please throw us a bone?

Thanks for your great products and support!!!!
 
#13 ·
Hi guys,
go a 2009 Challenger SRT8 6speed.

If you had to build a Challenger roadcourse racecar which is still used as some kind of daily driver which parts would bring the biggest efficiency regarding space savings?

Seats, carpet, ... are a startingpoint but what are the heaviest parts which can be exchanged?
Is it the Challenger body or the engine or .... ?

Thx a lot for this really nice piece of automotive history!
 
#67 ·
Obviously an aluminum block engine would save almost 100 lbs. The rest of the weight comes from unnecessary options (radio, sunroof, seats, etc...) and the body structure. When you start hacking out body structure, you are taking street risk and should substitute with cage structure which is very dangerous on the street without harnesses and a lid. The front and rear cradles are steel and heavy, too, but we have yet to see someone do one out of AL.
 
#14 ·
I have a '08 Charger SRT8. I want to replace the stock differential assembly. The unit I would like to install is the Limited Slip unit available in the Stick shift Challengers with the 3.73:1 gears. Talk to me. I need part #'s and any info on the install. I am an automotive instructor, my students are looking forward to doing the install.
 
#116 ·
I have a '08 Charger SRT8. I want to replace the stock differential assembly. The unit I would like to install is the Limited Slip unit available in the Stick shift Challengers with the 3.73:1 gears. Talk to me. I need part #'s and any info on the install. I am an automotive instructor, my students are looking forward to doing the install.
To make that work you will need a driveshaft from an 09 A/T and an axle from the 5.7 R/T. You will also need to replace the halfshafts, hub unit bearings, and new fasteners for the driveshaft (special pink ones). The cradle and rear floor will need some "massaging" to get the larger axle in. Keep in mind that the trans controller is going to get confused if you don't tell it that the gear ratio changed. There are aftermarket solutions that allow this modification so I hear ;)

I don't have all the part numbers in front of me, but your dealers parts department can help you out with that. I think one of the forum members might have posted them on here before too.
 
#74 ·
i guess my main question would be around CAI [cold air intake]

1) does the bore size of a CAI make a difference?
[mopar offered cai is not the largest, nor the smallest]

2) is there a measureable difference in using a CAI vs not using one?
The bore size of the CAI kit does affect the intake system tuning. In our development vehicles CAI kits have shown improved performance under most conditions.
 
#17 ·
My question is more geared to Mopar Performance. When I had my 2005 Magnum R/T they
made headers that came with the catted mid-pipes and the O2 extensions for about $1000.00 shipped. Will headers like that become available for both the SRT and R/T challengers?? The after market people are bending us over for their headers if you want the mid-pipes and extensions. I have the Challenger R/T and would really like to finish off my exhaust system with Mopar headers and cats.
 
#40 ·
My question is more geared to Mopar Performance. When I had my 2005 Magnum R/T they
made headers that came with the catted mid-pipes and the O2 extensions for about $1000.00 shipped. Will headers like that become available for both the SRT and R/T challengers?? The after market people are bending us over for their headers if you want the mid-pipes and extensions. I have the Challenger R/T and would really like to finish off my exhaust system with Mopar headers and cats.

Can't comment on future product but stay tuned.
 
#18 · (Edited)
2005 MRT with SRT8 suspension and wheels...

I have a 2005 MRT and I have - over time - improved upon the car by picking up a 300SRT suspension and hotchkiss sway bars (and the most beautiful wheels on any production car available from a SRT CHALLENGER :rock:)- and I have been extremely impressed with the improvements in handling.

I have heard that because of the dailmer/chrysler relationship, that some of the mercedes/AMG performance parts might be used to replace the cast suspension parts with aluminum componets designed for the mercedes platforms...

What dailmer/AMG suspension components (if any) could be installed on my 05 MRT?
Are there any other AMG parts that you know of that can be pilfered for our domestic LX's?

Thanks
Wayne
New Orleans , Louisiana

WHO DAT!
 
#59 ·
I have a 2005 MRT and I have - over time - improved upon the car by picking up a 300SRT suspension and hotchkiss sway bars (and the most beautiful wheels on any production car available from a SRT CHALLENGER :rock:)- and I have been extremely impressed with the improvements in handling.

I have heard that because of the dailmer/chrysler relationship, that some of the mercedes/AMG performance parts might be used to replace the cast suspension parts with aluminum componets designed for the mercedes platforms...

What dailmer/AMG suspension components (if any) could be installed on my 05 MRT?
Are there any other AMG parts that you know of that can be pilfered for our domestic LX's?

Thanks
Wayne
New Orleans , Louisiana

WHO DAT!
Bitter Divorce.... don't remember.
 
#19 ·
In our efforts to improve upon what are already two great powerplants (5.7 & 6.1), folks are putting the 6.1 intake manifold on 5.7's (either employing spacers that match the ports - or modifying the 5.7 cylinder head intake track) and moving the power band up with a modest increase in TQ/HP.

The 09' and later 5.7 powerplants have a composite intake manifold that appears to be similar to the SRT aluminum version (intake track length/volume and powerband).

1) Are the intake tracks lengths similar?
2) Would you expect similar results between the SRT (aluminum) and the composite 09' and later intake manifolds on either the 5.7 or 6.1 (09' composite version is significantly less mass and less heatsoak)?

Thanks, and Happy holidays...
 
#65 ·
The plastic intake on the 09 5.7L cars was derived after the 6.1L, by the same person in fact....so yes, they are pretty similar in design and function. They do however have some differences since the 09 5.7L has Variable Cam Timing and the 6.1L doesn't, so there were additional tweaks done to the 09 5.7L Plastic Intake for optimization with the cam. I'm not 100% sure, but the intake tracks should be similar to the old 5.7L vs. 6.1L. As far as performance goes, the plastic will certainly have less heat soaking issues, but again the systems are different. So, play at your own risk when it comes to spark knock due to airflow mixture motion. Let me know what you guys find.....I'd expect performance to be similar.

In our efforts to improve upon what are already two great powerplants (5.7 & 6.1), folks are putting the 6.1 intake manifold on 5.7's (either employing spacers that match the ports - or modifying the 5.7 cylinder head intake track) and moving the power band up with a modest increase in TQ/HP.

The 09' and later 5.7 powerplants have a composite intake manifold that appears to be similar to the SRT aluminum version (intake track length/volume and powerband).

1) Are the intake tracks lengths similar?
2) Would you expect similar results between the SRT (aluminum) and the composite 09' and later intake manifolds on either the 5.7 or 6.1 (09' composite version is significantly less mass and less heatsoak)?

Thanks, and Happy holidays...
 
#20 ·
So are catch cans . . . just kidding! First off, thank you for a wonder product. I am looking forward to more great products from SRT (like a 2012 Jeep SRT8 - ahem)!
Questions:
1) Are there any hidden EVIC screens or 'easter eggs' on the Jeep SRT8?
2) How can I get the pantone numbers for the interior color and HEMI Orange on the Jeep SRT8?
 
#22 ·
A question on WOT. At freeway speeds 110kph / 70mph, when punching the throttle to pass or accelerate, I have noticed a hesitated, surging acceleration. When this happens I back off and continue at normal speeds. I mentioned this to another member with an 2007 Super Bee at a meet, and he recognized the same type of symptoms. To this day, we can't figure it out. Again, it is very intermittent, but when it does hook up normally, well, we all know the feeling when that happens.. When you take it to the dealer, it's like going to the doctor, they can't diagnose anything out of order. Hopefully there may be an answer.
Thank you for your time.
 
#71 ·
Is the surging the entire pull until you let off the gas, or is it just when you tip-in on the throttle and then you pedal it? Also, it could be some knock retard stored in those cells when you hammer the gas. Do you know what your ACT is? Let me know some more details and I'll try to help out.

A question on WOT. At freeway speeds 110kph / 70mph, when punching the throttle to pass or accelerate, I have noticed a hesitated, surging acceleration. When this happens I back off and continue at normal speeds. I mentioned this to another member with an 2007 Super Bee at a meet, and he recognized the same type of symptoms. To this day, we can't figure it out. Again, it is very intermittent, but when it does hook up normally, well, we all know the feeling when that happens.. When you take it to the dealer, it's like going to the doctor, they can't diagnose anything out of order. Hopefully there may be an answer.
Thank you for your time.
 
#79 ·
Do you have any numbers of how much downforce the front and rear spoilers on the SRT Challenger generate? Does the SRT front spoiler create more downforce than the R/T spoiler or just duct some air to cool the brakes?

Thanks,

Bruce
The SRT8 at 130 mph generates about 60 lbs of downforce at the rear and about 150 lbs of lift at the front. That is MUCH better than most manufacturers in the industry who make much more lift. The R/T is less aggressive on both ends. The SRT airdam is better than the R/T one. You want aero understeer in the car to compensate for the natural instability as speed increases. This is why racecars have more wing in the back than splitter in the front. More down always feels better, but we have to balance aero downforce with drag.
 
#24 ·
The lack of 2009 Challenger Service Manuals has been raised on earlier chat sessions. Many of us have had them on order with the distributor, Tech Authority for months. We still have not seen a single one shipped. When we call Tech Authority, they say they are waiting on Chrysler to provide the materials.

We are blind without service manuals to help us correctly service and repair our vehicles.

Chrysler customer service has been unable to expedite or assist with this because they do not recognize the part number of the Service Manual in their system.

Is there some other way to escalate this issue?

Here is the link to Tech Authority

https://techauthority.gltghosting.c...rHome?storeId=10051&langId=-1&catalogId=10051
 
#25 ·
how far into an engines life can we see some oil consumption due to piston ring set-in? 3100 miles on my challenger r/t 6-speed, and its consuming a bit of oil (about 1/4 of a quart) over the last 1000 miles or so. funny thing is, it didnt do it during the first 1900-2000 miles. although, the last 1500 miles or so is when i started pushing it harder from time to time. i switched to mobil full synthetic 5w-20 at 1000 miles.

edit: shoot guys, sorry...i see this is only for SRT related questions...
 
#77 ·
It all depends on the duty cycle your car see's....I can seat (break-in) a set of rings really fast if you'd like me top ;) In all honesty, the first 500-1000 is the most critical at getting enough heat cycles through the engine. After 2000 miles, your rings should certainly be fully seated. With that said, depending on how hard you drive your car and where you drive it in the rpm range (you do have a 6spd), you could still consume a small amount of oil. 1/4qt over 1000 miles doesn't really concern me, but keep an eye on it and let us know at next months chat.
 
#57 ·
I want to install a Dual Shift Light on 2009 Challenger SRT8 6 speed.

What one is best to use: MSD, Autometer, etc?

Will MOPAR Performance offer a shift light?

Will the TA hood be offered with a fresh air intake system?
The only shift lights Mopar offers are included with Mopar branded tachometers. We are still investigating fresh air options for the T/A hood but are not ready to release any details at this point.
 
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