I have gone through the thread and picked out some of the really good stuff and put it all together. Enjoy!
Initially I understood the 2008 Challengers were going to have Limited Slip Diffs., but since then I've heard that only the 09's will have the "Sure Grip" version . I've had many people on this forum help explain the various types available, but I still don't know what's coming on my 08, Canadian 500.
SRT Engineer: The 2009 will be the first year for limited slip.Member Question:
From an overall project standpoint, what was the overall goal when creating the Challenger SRT8 when compared to the overall goal of the Charger SRT8. Basically, how did the vision differ from the Charger SRT8 when you set out to create the Challenger SRT8?
SRT Engineer: We wanted the Challenger SRT8 to have its own personality and driving experience, not just looks. We intentionally tuned the suspension to have a unique, slightly softer musclecar ride with different spring balance due to the different wheelbase. The shock tuning is unique, too. What we found was that we could make it ride much better than we expected and still keep the handling. As a result we retuned the '08 Charger and 300C srt8s to have a better ride. The Challenger SRT8 has its own exhaust tuning as well.Member Question:
Knowing the Charger SRT8 is very similar in platform, I am curious if there were there any significant barriers you ran into with the Challenger SRT8 or if a lot of the things were easily translated from the Charger into the Challenger with minimal tweaking.
SRT Engineer: There was a ton of tweaking, but it was not necessarily hard. In fact, it was nice to take another look at the platform. The more we get to develop a platform, the more refined the cars get, ala the Porsche 911.Member Question:
Is the Challenger SRT exhaust different from the Charger SRT? Does it still have the suitcase and Resonators? Will there be Mopar brand headers, Catback, or a complete system?
SRT Engineer: The '08 Challenger has the suitcase and resonators, although it sounds different than the Charger. The '09 different tuning due to the manual trans which the '09 auto will share. The backpressures are all the same, which is very low and barely legal. Mopar will have stuff, but it is not announced. Sit tight.Member Question:
Are SRT's getting the slotted rotors? Are the SRT rotors the same size as the Chargers?
SRT Engineer: The Challenger SRT8 brakes are identical to the Charger/300 SRT8, slots and all. '08 Challenger SRT8 and '09 Charger/300 SRT8 get knockback mitigation.Member Question:
Do the hood scoops on the SRT Challenger duct air to the intake or just flow cool air over the engine?
SRT Engineer: The ducts in the hood do not go to the engine intake. They would be a restriction.Member Question:
The 09 SRT will have a 6spd option. Is there a diff change or it the same diff that's in the charger? If it's the same will the 3.91 gears and carrier fit in the charger diff? What size if the new ring gear?
SRT Engineer: All of the 09 SRT's will get the new Challenger diff. The new diff is an heavy duty aluminum body limited slip with various ratios, 3.06 for the autonmatic, 3.91 for the manual transmission and a 3.73 ratio for the manual base car. The internal gear sets and carriers are interchangable for the new housing but not with prior differential models.Member Question:
The 6 spd manual trans (based off the Viper manual) has internal improvements (triple cone synchros and more) coupled with the Sachs dual disc clutch is an awesome package.
Previous was 215mm and for the 09MY it is a 226mm ring gear pitch diameter.
I noticed on the Challenger concept car that there wasn't a whole lot of room for an increase in tire size in the rear to improve "launch" traction. Does the production Challenger have the same space restriction?
SRT Engineer: The Challenger has the same tire envelope as the Charger.Member Question:
Is the Suregrip coming out for the 09's an Auburn (cone) or clutch style differential?
SRT Engineer: The Limited Slip available in 2009 uses a multi-plate clutch pack. Unlike the Auburn and most multi-plates that used steel on steel friction surfaces, we are using a carbon kevlar friction material.Member Question:
Why doesn’t the summer tire option for the SRT Challenger come with P255/45ZR20 tires all around instead of P245s in front and P255s in the rear? Also, is there much of a drop-off in handling/performance between the Goodyear Eagle F1 Supercar tires and the Goodyear Eagle RS-A all-weather tires?
SRT Engineer: 255 F1's hit the spash shields at full turn and the fend lips at full jounce. You can probably get away with running them up front if you drive like a wuss. No complaining allowed, though. The RS-A's need to be snow capable which dictates the compound. The compromises the performance in other conditions. The RS-A's actually have more aggressive sidewall construction than the F1 to compensate for the compound and tread differences. We made them as close to each other as we could.Member Question:
Why doesn’t Dodge put on better tires like the Bridgestone Potenza Pole Position or Michelin Pilot Sport PS2?
SRT Engineer: Our Dynamics guy challenges you to show up in Michigan in your car with whatever aftermarket tires you want in the same size as stock and we'll do a runoff on all our tire performance criteria. The Goodyear F1's will win. You want more life, you'll get less stick.Member Question:
For the '09 MY I believe I had read that the 6-speed w/Trak Pak resulted in the muffler being replaced with two resonators. Are there any other exhaust related modifications with the Trak Pak?
SRT Engineer: There is no Trak Pak for the Challenger SRT8. Member Question:
Is there something more complex than monitoring the A/F ratios and knock sensors fooling us into thinking we have a good tune on our cars when we really don't? Most people are tuning with a sniffer on the exhaust or a bung into the exhaust manifold. Any help is appreciated - thanks. I'm of the crowd who really appreciates the starting point you give us.
SRT Engineer: If the general public believes that the calibration engineers leave any ponies on the table when competative pressure around Detroit to one up the industry are so politically charged, they are wrong. This is a bunch of racers and we want always to win. If a change is made to hardware such as long headers which we could not certify for emissions or noise, Fuel air and spark need to be modified. We are also sensitive to the cost of our vehicles and spec the parts to meet our functional objectives. Some components may not like being pushed harder.Member Question:
Why did you guys wait till now to incorporate a 6 speed option with the Hemi engine?
SRT Engineer: The all-new Tremec TR6060, which was developed for the Viper, just came along in 2008. It was a perfect opportunity to put a modified version of the same updated/improved TR6060 Viper gear box in the Challenger.Member Question:
Why are you just now coming out with a true limited slip differential as opposed to the brake limited diff in the current lx's?
SRT Engineer: Same answer as above... new car... new opportunities to improve performance. That's what you want, right?Member Question:
Current road tests of the 2008 Challenger SRT has it consistently doing the 1/4 mi. in 13.3 sec. and 108 mph. How much faster, will the 6-speed manual be in the 2009?
SRT Engineer: Their so close that were actually reporting the same performance numbers, however, top speed is a little higher on the manual...and you should see fuel economy improvements.Member Question:
Why would the manual have a higher top speed if it has a lower gear ratio than the autostick? Also, does the manual have the same $2,100 gas guzzler tax?
SRT Engineer: The Manual is a 6 speed and has 5 and 6th are both overdrive gears there only to help fuel economy. We match it to a more agressive final drive ratio for a ballance yet agressive launch. The MTX will have a reduced gas guzzler tax and we are in final certification with EPA as of today.Again, I would like to thank the SRT Engineers for spending their time with us yesterday and we hope to do it again sometime soon! Cheers!