SRT Engineers' Answers

[Cuda340]

Here are some of the SRT engineers' answers to the questions posed on tonight's very informative Chat Session (there are some "gold nuggets"):

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 muscle car 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.

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.

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.

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.

The ducts in the hood do not go to the engine intake. They would be a restriction. The scoops have been fully water tested.

All of the 09 SRTs will get the new Challenger diff. The new diff is an heavy duty aluminum body limited slip with various ratios, 3.06 for the automatic, 3.91 for the manual transmission and a 3.73 ratio for the manual base car. The internal gear sets and carriers are interchangeable for the new housing but not with prior differential models.

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.

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. Also, 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? Same answer as above... new car... new opportunities to improve performance. That's what you want, right?

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 aggressive final drive ratio for a balance yet aggressive launch. The MTX will have a reduced gas guzzler tax and we are in final certification with EPA as of today.

The Challenger SRT8 and 300 SRT8 wheels are 6 pounds lighter than the Charger SRT8 and the Magnum SRT8. (Is that stamp a change in manufacturer or just a newly added stamp?) Same weight...newly added stamp!
255 F1's hit the splash 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. Most people love the 20's. You are welcome to put 18" wheels on if you want.

Don't believe everything you read. 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.

Does the 6.1 now have an oil dip stick so that we can check the oil level?
The 6.1L has a dip stick.

How theft-proof is the ignition lock?
The Challenger has a digital key.

Is it true that the computer learns your driving habits and the engine will not “come alive” if you drive too conservatively? The trans controller and the engine controller both adapt to the car more than your driving habits. It compensates for build and system variables of the components to torque and time events.

If you have tuned the SRT for maximum performance, why are owners buying tuners like Predator and Diablo to gain more hp? I would not spend the money as most of the aftermarket tuning packages we have evaluated may put spark in or take fuel out of the wrong places and create durability issues.

What you think of the new high energy spark plugs - i.e. Halo, Pulstar and like that for improved performance, better fuel economy and reduced emissions? Snake Oil


If the general public believes that the calibration engineers leave any ponies on the table when competitive 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.

The Caliber SRT4's have spacers because they are lowered much more from the regular Caliber than the SRT8s are from regular LX/LCs. The spacers are there mainly to get the Calibers off the clamshells in the plant. The Challengers shouldn't be getting damaged any more than 300C and Charger SRT8's. They have the same clearance and approach angles.

The ECU adjusts boost to generate the requested torque at a set of given conditions. The boost limit will also vary according to the ambient conditions.

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? 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- 1 mpg.

Don't know that level of detail on the R/T. They stole our seats out of the 300C SRT8 (Chargers, Magnums, and Challenger SRT8s have stiffer bolsters). We doubt they made a new hybrid seat out of the cheap bottom and good seatback.

The suits and bean counters won the fight on that 4 spoke, and we fought for a new wheel. The armature tooling and impact validation of a new wheel is quite expensive (like 7 figures), though

Is the new re-formulated Mobil 1 0W40 oil still ok to use on my 2006 SRT8? It will be fine.

[EVERRET]

Nice Round-up of the session..... Thanks !

[RoostKing]

Thanks for the Cliff Notes!

[ekool]

What you think of the new high energy spark plugs - i.e. Halo, Pulstar and like that for improved performance, better fuel economy and reduced emissions? Snake Oil

This is my favorite... its something that we all kind of "feel" and and "know" but its hard to get someone "in the know" to really take a stand on the issue.

[djwhog]

Very nice thank you much!

[425hpChargerSRT8]

Originally Posted by ekool

What you think of the new high energy spark plugs - i.e. Halo, Pulstar and like that for improved performance, better fuel economy and reduced emissions? Snake Oil

This is my favorite... its something that we all kind of "feel" and and "know" but its hard to get someone "in the know" to really take a stand on the issue.

lol, that was funny. I remember reading that. It is hard to get those guys at times to give you their honest opinion about that stuff. I guess its more of a "if you think so, then yes" lol