SRT Engineer Chat HERE on January 16th!

[SRT Engineers]

Nader:

• I just finished reading the ACR article in the most recent Viper Magazine. In the article it summarizes the ACR suspension mods. In particular it mentions, "The more aggressive ACR suspension setup requires increased roll stiffness up front, so a new stiffer front stabilizer bar is included." Since I have very similar mods namely lighter wheels and non runflats, Moton adjustable suspension, and stoptech rotors would you recommend the same thicker stabilizer bar? I do track the car 2-3 times a year. The car handles extremely well but not sure i should be running a thicker bar in conjunction with my more aggressive suspension setup. Also, with the StopTech rotors do you have any pad recommendations for light track use but mostly street driving?

The ACR (and all Vipers) are tuned as a complete system. When we put all of the components together that make up the ACR (aero, springs, dampers, tires, wheels, brakes, etc) we found that the stiffer front anti-roll bar was needed to control the high amount grip resulting at the tire.

In your particular situation, it would be impossible to make a recommendation on the front anti-roll bar without knowing everything about your car and then driving to see how it handles. There is no magic speed in the front anti-roll bar stiffness. If you car handles well and you have no complaints of the amount of chassis roll or the handling balance at the limit, I would stick with what you have. All other things being equal, an increase in front anti-roll bar rate will usually lead to more understeer (push) through corners, although there are certainly exceptions to this rule. The solid front bar is also heavier.

[SRT Engineers]

The front timing covers (that include the oil pump housing) for the 03-06 Vipers have been on backorder from the dealer for many months (with no expected new production date). Will these be available anytime in the future? Is this part available with the short block currently available?

We don't have service folks here but we'll pass that one along.

Will the clutch, transmission and differential for the 08 fit the 03-06 models?

There are some of thses types of packages in development.

I have numerous customers asking for the ACR package upgrade for their current 08 models. Will there be a package to convert non-ACR cars?

We do have some plans along these lines. Of course, if someone wants the look right now they should sign up for the car.......

I am very aware of the concerns with emissions and performance upgrades on the new models. Viper owners are known for wanting to increase the performance of their vehicles. With the current concerns, will Dodge be producing performance products (for track and street) that will allow us tuners to upgrade these cars for our customers? In the past products have been developed, but they have either been too late to the game or did not include an emissions certification (track only). This has prompted the aftermarket to jump in.

The Venom system with ETC doesn't give you very much flexibility. Now that the production car has been launched, we are looking a what we can do for the tuner. We can tell you now, however, that there is no opportunity to "mix and match" components. A given cal will only be good for a given stage kit.

How long will Dodge support the Gen 1-2 Models? It seems that most manufacturers support product for 10 years. Can we expect this from Dodge? Parts for the early models are getting thin (I can understand why). Do you think the hard parts will continue to be available for over 10 years?

Again, the right folks aren't in the room.



Viper has been a great journey for all of us, I hope all at SRT and the new Management will continue the passion.

Dan Cragin
DC Performance Inc

[SRT Engineers]

doctorbob: I would like to know the expected wear on the Pilot Cup tires of the ACR and wear if you put on stock PS2s. Obviously, you're just not going to be taking this car only to and from the track so I was interested on advice if you were to take the ACR on an extended trip.


The Treadwear Rating on the ACR is: 80
This compares to the Viper SRT-10’s: 220

As you will expect, tire wear is not an exact science and is completely dependent on driving style. The ACR PSC tires will wear quicker, but worth the performance advantage at a track.

[SRT Engineers]

rcl4668: What pad would you recommend for the Stoptechs for someone who had to run one pad for both street and running 6-7 HPDE/track days per year?


The Viper SRT-10 and ACR share the same brake pad. We have found this brake pad to be an excellent compromise for both street and track use (the compound is very close to a mild racing specification already).
If you want to go more aggressive, the Competition Coupe teams use many different pads that seem to work well with the Viper braking system. PFC 97 is a medium aggressive race pad while Mintex F2R or Ferodo FCP1281R are aggressive race pads. All of these racing pads will improve the initial bite, but you will trade off rotor wear, brake squeal, and ease of street driving. Also be careful with brake temperatures. As you substitute more aggressive race pads, you also increase the heat transfer rate to the brake fluid. Competition Coupes come equipped with large brake cooling systems for this reason and all are filled with Motul racing brake fluid.

[Nader]

Originally Posted by SRT Engineers

Nader:

• I just finished reading the ACR article in the most recent Viper Magazine. In the article it summarizes the ACR suspension mods. In particular it mentions, "The more aggressive ACR suspension setup requires increased roll stiffness up front, so a new stiffer front stabilizer bar is included." Since I have very similar mods namely lighter wheels and non runflats, Moton adjustable suspension, and stoptech rotors would you recommend the same thicker stabilizer bar? I do track the car 2-3 times a year. The car handles extremely well but not sure i should be running a thicker bar in conjunction with my more aggressive suspension setup. Also, with the StopTech rotors do you have any pad recommendations for light track use but mostly street driving?

The ACR (and all Vipers) are tuned as a complete system. When we put all of the components together that make up the ACR (aero, springs, dampers, tires, wheels, brakes, etc) we found that the stiffer front anti-roll bar was needed to control the high amount grip resulting at the tire.

In your particular situation, it would be impossible to make a recommendation on the front anti-roll bar without knowing everything about your car and then driving to see how it handles. There is no magic speed in the front anti-roll bar stiffness. If you car handles well and you have no complaints of the amount of chassis roll or the handling balance at the limit, I would stick with what you have. All other things being equal, an increase in front anti-roll bar rate will usually lead to more understeer (push) through corners, although there are certainly exceptions to this rule. The solid front bar is also heavier.

Answered above. Thanks.

[Y2K5SRT]

Has Mopar set a time line for releasing performance parts for the 2008 (headers, etc.)? This is my first and last question - gotta run to the airport!





PS. GREAT job on the SRT4!!

[SRT Engineers]

Reply for Bobpantax and Vipermann on engine/trans mounts:

'08 Viper engine mounts are increased durometer (harder) compared to the '06 engine mounts to handle the increased engine output. The '08 engine mounts will fit the '03 to '06 cars for those who want to upgrade. The harder engine mounts help resist engine roll which contributes to better shift precision. The Mopar 'Comp Coupe' type rear trans mount will also fit the '08 Viper.

[Nader]

Not sure if you saw these questions or just working on them...

When driving i get an some "creaking" from my top when it is up. It sounds like it is coming from overhead and where the top meets the windshield. If i pull on the driver side handle on the top it stops. Does it need to be adjusted or tightened? Or does it need to be lubricated and if so where and how. Are there any general maintenance procedures for the hardware on the top?
Why the move back to two independent throttle bodies?
Mopar is currently selling the 2008 hood. Questions: Does the intake inlet of the 08 hood line up with the 03-06 filter box? The 08 hood does not come with the vent covers from Mopar nor are they listed as a Mopar part. Are they sold seperately? How does one obtain the vent covers if they chose to change to an 08 hood?

[SRT Engineers]

Nader
Mopar is currently selling the 2008 hood. Questions: Does the intake inlet of the 08 hood line up with the 03-06 filter box? The 08 hood does not come with the vent covers from Mopar nor are they listed as a Mopar part. Are they sold seperately? How does one obtain the vent covers if they chose to change to an 08 hood?

The 2008 hood will fit on 03-06 Vipers but you need to trim the inner panel to look like the earlier hoods in the latch area at the front of the hood.

[SRT Engineers]

black08: Obviously, thousands of hours were logged on the track during the development of the ACR. I was wondering if the SRT engineers could give us an idea of how much quicker the ACR was on the track versus the regular '08 model?


We have tested at many tracks and the results vary with them. At a 2.0 mile track (1:30 lap time range) with high speed corners where the aerodynamics can show off, the ACR is typically 3 seconds faster than the 2008 Viper SRT10 and 4.5 seconds faster than the 2006 Viper SRT10.

[SRT Engineers]

JonB - PartRack: SRT Engineers, FBW Throttle Questions Please:

• How quickly does "The Computer" allow WOT on the 2008 Fly-By-Wire throttle? My Charger Daytona only allows 75% of WOT in 1st when I try to go WOT, and that is meted out til 2000 RPM. How intrusive is the 2008 FBW WOT management? Do we get Full Throttle in 1st?
• The VENOM allows WOT in all gears... there is no torque management.
• How quickly does 2008 throttle go CLOSED-Idle? My Gen 1 went CLOSED/IDLE as soon as I lifted. GREAT on track. Gen 2 "lifts" in a 2-step ISM process, something about better emission burnoff. (I dont like this.) Since the 2008 apparently has no ISM, does it still need to "LIFT" more slowly? When I LIFT I want to go in 1 fast step to idle, please.
• There is a bit of a thottle shut blend to maintain emissions and keep the cats alive under the lift foot conditions.

Thanks again SRT: "WHAT A COMPANY" !!! Jon Brobst

[Nader]

Originally Posted by SRT Engineers

Nader
Mopar is currently selling the 2008 hood. Questions: Does the intake inlet of the 08 hood line up with the 03-06 filter box? The 08 hood does not come with the vent covers from Mopar nor are they listed as a Mopar part. Are they sold seperately? How does one obtain the vent covers if they chose to change to an 08 hood?

The 2008 hood will fit on 03-06 Vipers but you need to trim the inner panel to look like the earlier hoods in the latch area at the front of the hood.

Any comments on how to get the factory grills that cover the vents on the 08 hood?

[Bobpantax]

"The Viper Nation's collective voice needs to be heard." Respectful Email just sent to all three.

[SRT Engineers]

Question: How much slower is the '08 ACR than a non acr '08 as far as top speed and 1/4 mile times?

The ACR 0-60 times are identical to the 08 SRT-10.

In the 1/4 mile, the ACR is about 0.1-0.2 seconds slower than the SRT-10.

We just tested the top speed of the ACR at our Arizona Proving Grounds and reached a top speed of 177 mph.

Of course the reason for the top speed reduction is the drag trade-off due to the downforce improvements. Although the wing, splitter, and diveplanes are extremely efficient (increase downforce at around a 7:1 ratio to drag penalty), the top speed will suffer. Don't worry too much, if they can catch back up to you on the straight, they'll have no chance of staying with you through the corner.

[SRT Engineers]

rcl4668
Q1: What are the exact weights for the 2008 Coupe versus the 2008 Convertible. Is there still a weight differential of about 30 lbs as on the 2006 model? (With the convertible actually being lighter.)

A1: Weight will vary from car to car but these are the official estimates
3,450 lbs. (1564.9 kg) Coupe
3,440 lbs. (1560.4 kg) Convertible
3,408 lbs. (1552 kg) ACR
3,366 lbs. (1533 kg) ACR Hard Core Package


Q2: An article in a recent car magazine stated that the wheel used on the 2008 Viper ACR is a Sidewinder wheel that has been improved over prior Sidewinder rims (like the one one used on the 2005 Copperhead limited edition convertible) using finite element analysis. Is this accurate or is the ACR rim essentially the same albeit with a black paint finish?

A2: It's more than just black paint. The ACR Sidewinder Wheels are further optimized for the ACR using the latest FEA techniques. The spoke sections have been updated for increased performance vs. weight