rcl4668
Enthusiast
FYI, I made the following post on the srt/caliber forum SRT engineer chat (similar to the ones we enjoy periodically on this site) and got the following response:
"Thank you for taking the time to do this chat.I have a 2008 Viper convertible that will hopefully be
arriving in the next few weeks and I am planning on
retrofitting certain components from the 2008 ACR to my
convertible.
First, what are the exact weights of the 2008
convertible and the coupe version? Is the convertible
still about 30-40 lbs lighter than the coupe?
Second, what are the exact technical differences
between the 2008 ACR stoptech rotors and the two-piece
aerorotors that I can buy direct from Stoptech? From
prior info on the VCA website it seems that the only
differences are that the center aluminum hat has a
different anodized color and has a small "stoptech"
logo on it. Stoptech also believed that the Mopar unit
has a protective anti-corrosion coating. Do you know
what that coating is? Zinc? Those differences aside,
are there any performance or structural differences
between the "over-the-counter" Stoptechs and the
Mopar-branded Stoptech rotors?
Similar question for the KW dampers on the ACR, are
these units specific to the ACR and if so in what
respect? Cosmetic finish or some mechanical difference
or difference in the calibration compared to what I
could buy from KW? Does the addition of the ACR KW
suspension wind up adding weight or saving weight
versus the stock suspension components? If so, how
much?
Finally, I plan on adding a set of Sidewinder wheels
from the ACR with the Michelin Pilot Sport Cup tires in
the stock ACR sizes, 345/30/19 rear and 295/30/18
front. This rim/tire combo will be used for track/HPDE
events only. The stock front tire size on the "regular"
2008 Viper is 273/35/18. Since I will not be adding
the aero components (canards, splitter and rear wing)
or the thicker front stabilizer bar from the ACR will
using the 295/30/18 tire size result in too much
oversteer on my stock suspension? Would I be safer
using the next narrower Pilot Sport Cup size of
285/30/18 to be closer to the spec 275/35 size?
Thanks so much for your help and feedback. Keep up the
great work!
/Rich"
The SRT engineers responded as follows:
"First: Not really prepared with the viper weights. The difference between the coupe and conv. are unchanged, but the new tires are lighter. We are prepared with Caliber SRT4 weights...
"As for the Brake Rotors they are inded different. We have changed coatings to align with Chrysler standards for corrosion protection on the rotor, hat, and bobbins. Sorry don't have the exact specs for the coatings.
"The ACR suspension is a total new development from the Mopar or KW offerings in the aftermarket. We have worked with KW to provide the best valving and spring rates to match the aero and tire loads that can be generated. No exact ACR weight measurements at this time but they are within 1lb. As a comparrison the Mopar Performance pieces from KW are 1.5lbs lighter per corner. Your biggest corner weight savings will come with the Sidewinder wheels and ACR rotors...a savings of 60lbs total.
"Finally: The 295's will reduce understeer a bit. I'd try the 295's before the 285's. Depends on your preferred balance as a driver."
"Thank you for taking the time to do this chat.I have a 2008 Viper convertible that will hopefully be
arriving in the next few weeks and I am planning on
retrofitting certain components from the 2008 ACR to my
convertible.
First, what are the exact weights of the 2008
convertible and the coupe version? Is the convertible
still about 30-40 lbs lighter than the coupe?
Second, what are the exact technical differences
between the 2008 ACR stoptech rotors and the two-piece
aerorotors that I can buy direct from Stoptech? From
prior info on the VCA website it seems that the only
differences are that the center aluminum hat has a
different anodized color and has a small "stoptech"
logo on it. Stoptech also believed that the Mopar unit
has a protective anti-corrosion coating. Do you know
what that coating is? Zinc? Those differences aside,
are there any performance or structural differences
between the "over-the-counter" Stoptechs and the
Mopar-branded Stoptech rotors?
Similar question for the KW dampers on the ACR, are
these units specific to the ACR and if so in what
respect? Cosmetic finish or some mechanical difference
or difference in the calibration compared to what I
could buy from KW? Does the addition of the ACR KW
suspension wind up adding weight or saving weight
versus the stock suspension components? If so, how
much?
Finally, I plan on adding a set of Sidewinder wheels
from the ACR with the Michelin Pilot Sport Cup tires in
the stock ACR sizes, 345/30/19 rear and 295/30/18
front. This rim/tire combo will be used for track/HPDE
events only. The stock front tire size on the "regular"
2008 Viper is 273/35/18. Since I will not be adding
the aero components (canards, splitter and rear wing)
or the thicker front stabilizer bar from the ACR will
using the 295/30/18 tire size result in too much
oversteer on my stock suspension? Would I be safer
using the next narrower Pilot Sport Cup size of
285/30/18 to be closer to the spec 275/35 size?
Thanks so much for your help and feedback. Keep up the
great work!
/Rich"
The SRT engineers responded as follows:
"First: Not really prepared with the viper weights. The difference between the coupe and conv. are unchanged, but the new tires are lighter. We are prepared with Caliber SRT4 weights...
"As for the Brake Rotors they are inded different. We have changed coatings to align with Chrysler standards for corrosion protection on the rotor, hat, and bobbins. Sorry don't have the exact specs for the coatings.
"The ACR suspension is a total new development from the Mopar or KW offerings in the aftermarket. We have worked with KW to provide the best valving and spring rates to match the aero and tire loads that can be generated. No exact ACR weight measurements at this time but they are within 1lb. As a comparrison the Mopar Performance pieces from KW are 1.5lbs lighter per corner. Your biggest corner weight savings will come with the Sidewinder wheels and ACR rotors...a savings of 60lbs total.
"Finally: The 295's will reduce understeer a bit. I'd try the 295's before the 285's. Depends on your preferred balance as a driver."
