TA size Girodisc Rotors

[esm_viper]

Is there any interest in having Girodisc make their rotors in the same size as the TA rotors but priced the same as their narrow annulus rotors on their website, $950 a pair rotor and hat? I spoke with Mike Owen and they'd be willing to produce these rotors for us if there is at least 5 people that commit to buying. I think it'd be a great cost effective option for us non-ACR guys with stock rims. Let me know if anyone is interested and I'll start a list.

Eric

List of people interested:

1. esm_viper
2. ViperGeorge
3.
4.
5.
6.

[Voice of Reason]

Is that cost rotor plus hat or just rotor and then reuse our hats? If just the rotors is that really much cheaper than getting Brembo replacement rotors?

[esm_viper]

Is that cost rotor plus hat or just rotor and then reuse our hats? If just the rotors is that really much cheaper than getting Brembo replacement rotors?

The Girodisc's are $950 a pair hat and rotor. Around $2,000 for 4. I've been emailing Jon B and the Brembo TA rotors are around $1,000 EACH. Around $4,000 for 4.

[ViperGeorge]

If they are the same thickness, diameter, and otherwise the same as the OEM TA rotors, I'd be in for a set. My ACR-E has steel TA brakes.

[esm_viper]

If they are the same thickness, diameter, and otherwise the same as the OEM TA rotors, I'd be in for a set. My ACR-E has steel TA brakes.

Sending another email now.

[Voice of Reason]

The Girodisc's are $950 a pair hat and rotor. Around $2,000 for 4. I've been emailing Jon B and the Brembo TA rotors are around $1,000 EACH. Around $4,000 for 4.

$1k sounds like it includes the hat unless the price for just the rotor has gone way up. I would have swore he had a post early last year where a pair of rotors only (no hats) was about a grand.

[Special Ed]

$1k sounds like it includes the hat unless the price for just the rotor has gone way up. I would have swore he had a post early last year where a pair of rotors only (no hats) was about a grand.

If the current price is $1000 and the price a year ago was $1000 how has the price gone way up? Am I missing something?

[esm_viper]

That's ridiculous if they doubled in price! I'll try and get clarification. This is copied from an email from Jon. MSRP on TA rotors is $1265 Each! 25% off = $949 each by credit card. Pay with check, or B of A or USBank direct walk-in deposit = 27% off.

Here's an old link to a Jon B post from 2015.

https://driveviper.com/forums/threads/7764-SPRING-BRAKE-SALE-Rotors-for-ACR-TA-and-ACR-X-and-a-One-Only-G5-BBK

-Brembo Slotted Rotors for G5/TA: SALE - $1425/Pr. Hat-Ring-Hardware. NOTE: Mopar/Dodge MSRP $2400/pr!!
--Full set of 4 TA Rotors SALE: $2795/4. (Dodge-Mopar $4800)
[Wider Annulus=smaller hat=more swept area=HEAVIER ROTOR. Larger Pads] TA BREMBO Pads $279 MSRP $322.
---We also have PFC-01 Pads for -X and TA in stock at $299/set.

----TA / BREMBO SLOTTED ROTOR RINGS for OE Replacement: SALE $869/pr + hardware recommended $90 per.

[esm_viper]

Jon just said this is the CURRENT pricing and that Fiat raises their prices monthly. MSRP on TA rotors is $1265 Each! 25% off = $949 each by credit card. Pay with check, or B of A or USBank direct walk-in deposit = 27% off.

[ViperGeorge]

That's ridiculous if they doubled in price! I'll try and get clarification. This is copied from an email from Jon. MSRP on TA rotors is $1265 Each! 25% off = $949 each by credit card. Pay with check, or B of A or USBank direct walk-in deposit = 27% off.

Here's an old link to a Jon B post from 2015.

https://driveviper.com/forums/threads/7764-SPRING-BRAKE-SALE-Rotors-for-ACR-TA-and-ACR-X-and-a-One-Only-G5-BBK

-Brembo Slotted Rotors for G5/TA: SALE - $1425/Pr. Hat-Ring-Hardware. NOTE: Mopar/Dodge MSRP $2400/pr!!
--Full set of 4 TA Rotors SALE: $2795/4. (Dodge-Mopar $4800)
[Wider Annulus=smaller hat=more swept area=HEAVIER ROTOR. Larger Pads] TA BREMBO Pads $279 MSRP $322.
---We also have PFC-01 Pads for -X and TA in stock at $299/set.

----TA / BREMBO SLOTTED ROTOR RINGS for OE Replacement: SALE $869/pr + hardware recommended $90 per.

So, the Girodisc rotors are $950 a pair including hats. Half the price of the Mopar/Brembo versions. Correct???

[esm_viper]

I believe so if we can get at least 5 people to commit!

ViperGeorge - You are in a different boat with your ACR, according to Mike at Girodisc, the iron rotors they are selling to the ACR guys are the same size as the carbon rotors.

[darbgnik]

I believe so if we can get at least 5 people to commit!

ViperGeorge - You are in a different boat with your ACR, according to Mike at Girodisc, the iron rotors they are selling to the ACR guys are the same size as the carbon rotors.
His came with TA rotors, not converted carbon rotors.

[esm_viper]

I knew that. But now that I think about it, I forgot that he also has the 4 piston calipers. My mistake.

[esm_viper]

Info from Girodisc.

1. *Yes $950 is for a pair of the complete assembles ready to bolt onto the car.
2.* Yes they are 355mm x 32mm with the larger annulus just like the OEM rotors.
3.* There are two different variants of the wide annulus rotors, the early ones which are curved vane and have similar hardware to ours, there is an outside chance that our rings will work on those hats but if I recall I believe the PCD is a little off.* The later wide annulus rotors which are pillar vane and have the H-bobbin hardware will definitely not work with our rotors.
4.* The cost of the replacement rings is $600 for the pair and that price includes all new hardware as well

[esm_viper]

I think this is a no brainer.... let's start a list and get these made!

[ViperGeorge]

I believe so if we can get at least 5 people to commit!

ViperGeorge - You are in a different boat with your ACR, according to Mike at Girodisc, the iron rotors they are selling to the ACR guys are the same size as the carbon rotors.

No, my ACR is an ACR/TA it came equipped from the factory with TA brakes. It has the same brakes as a TA, it did not come with Carbon Ceramic Brakes. If the rotors are the same as a TA's then I'm in.

Please explain Girodisc's number 3 comment. Will their rotors (hat and all) work on a 2017 TA brake setup?

[kriskyk]

Are these TA rotors at a more economical price point or something more?

I'm delineating over brake upgrade options for track days.

[sharmut]

@ esm_viper
Can you check with GiroDisc if the VANE count is the same as the OE Brembo? If the ring material hardness is comparable to the OE TA Brembo, they could hold up as well. Do know someone with a RS4 with GiroDisc, did not hold up as well as he hoped with track use and the weight of that car.

While looking around for alternatives and found a site listing Brembo type-3 replacement rings (BRE-906530 BREMBO BRAKE ROTOR 355MM X 32MM) for ~$474 each, have not had time to research fitment to TA OE hats.

Currently trying out a set of AP-Racings J-hook rotors (narrow annulus) with ST47 and ST43 pads. They have a higher vane count and lighter. Only had them out for 2 track sessions, too early to say how well they will hold up.

[esm_viper]

No, my ACR is an ACR/TA it came equipped from the factory with TA brakes. It has the same brakes as a TA, it did not come with Carbon Ceramic Brakes. If the rotors are the same as a TA's then I'm in.

Please explain Girodisc's number 3 comment. Will their rotors (hat and all) work on a 2017 TA brake setup?

The #3 comment was in response to my question... 3.* Will the Girodisc rotor bolt to the Brembo hat?

- - - Updated - - -


Are these TA rotors at a more economical price point or something more?

I'm delineating over brake upgrade options for track days.

Yes they are.

[ViperGeorge]

Are these TA rotors at a more economical price point or something more?

I'm delineating over brake upgrade options for track days.

TA rotors have a larger annulus (larger swept area) and are heavier than standard Viper rotors. Despite what some people may think this does not improve brake torque but it does improve cooling. You could use them on a standard Viper as the TA uses the same calipers as a non-TA. Pads are different though. The pads for a TA have more swept area to them, they stick out the bottom of the caliper where stock Viper pads do not.

TA brakes are less likely to fad than stock Viper brakes. as there is more area and mass to dissipate heat.

I went with TA brakes on my ACR-E as the replacement cost of the Carbon Ceramic brakes on an ACR are super high. When you track it a lot this adds up.

[kriskyk]

This is very helpful

Have you ever felt that the TA brakes left much more to be desired?

Trying to decide if I just go the TA route or just buy a big brake kit

[ViperGeorge]

This is very helpful

Have you ever felt that the TA brakes left much more to be desired?

Trying to decide if I just go the TA route or just buy a big brake kit

With the right pads (I use Raybestos ST45s in the front and ST43s in the rear) the car stops like you threw out anchor. On my ACR-E I do not notice the dreaded rear end wiggle under heavy braking either. On my 15 TA 2.0 the rear end wiggled a lot until I changed the rear calipers for the reduced bias Racing Brake setup. As I understand it the ACRs have a different brake bias than the TAs.

[esm_viper]

Here's all we need to do to start production, I've added a list of interested people and if you wouldn't mind updating us if you called and put down a deposit. They are closed today but I plan on calling them Monday to put down my deposit.

A 50% deposit from 5 people would do the trick, so $2375. People can call 360-306-3263 in with their CC info or I can send PayPal invoice to everyone whichever is easiest for you guys.

[Special Ed]

With the right pads (I use Raybestos ST45s in the front and ST43s in the rear) the car stops like you threw out anchor. On my ACR-E I do not notice the dreaded rear end wiggle under heavy braking either. On my 15 TA 2.0 the rear end wiggled a lot until I changed the rear calipers for the reduced bias Racing Brake setup. As I understand it the ACRs have a different brake bias than the TAs.

I run ST47 front and ST43 on the rear on my TA and the rear wiggle hasn’t happened since I changed to this pad combination and you better have your belts tight or you will be eating the steering wheel.

[kriskyk]

Are these rotors similar/same to the ones we are discussing?

http://www.racingbrake.com/Two-Piece-Rotor-Surface-Mount-Slotted-Viper-A-p/2343.htm

http://www.racingbrake.com/Two-piece-rotor-Slotted-Surface-Mount-Dodge-V-p/2504.htm

[ViperGeorge]

Are these rotors similar/same to the ones we are discussing?

http://www.racingbrake.com/Two-Piece-Rotor-Surface-Mount-Slotted-Viper-A-p/2343.htm

http://www.racingbrake.com/Two-piece-rotor-Slotted-Surface-Mount-Dodge-V-p/2504.htm

I would say no. The Racing Brake listing does not mention the TA. The TA has different rotors than other Vipers. They are the same diameter as a regular non-ACR Viper but the swept area (annulus) is larger. In other words the hat has a smaller diameter even though the total assembled rotor is the same size as a regular Viper. This allows you to use a pad with more surface area and these pads actually stick out the bottom of the Viper caliper.

Note that Racing Brakes refers to the rotors in your link as "oversize", meaning a larger diameter. A larger diameter rotor would require brackets to move the caliper further out. The TA's calipers are in the same place as a regular Viper, they were not moved as the rotor has the same physical diameter.

Most ACRs came with Carbon Ceramic Brakes with Carbon rotors. These rotors are much larger than non-ACR Vipers. The exception is if you ordered an ACR with steel brakes (which was an option) you received the TA rotors. That is what my ACR-E has.

[Racingbrake]

Same 355x32mm but RB offers 3 different set up:

P/N 2218 ($898/2 rotors): RB Surface Mt design for Stoptech replacement (Pad=D968/53mm depth) - In stock.


http://www.racingbrake.com/Two-piece-rotor-Slotted-Surface-Mount-Viper-F-p/2218.htm

P/N 2343 ($999/2 rotors): RB Center Mt design upgrading from TA Brembo surface mt (Pad=D1001/60mm depth) - In stock.
- This is the same two piece rotors that helped Igor at Momentatry Racing with podium wins -


http://www.racingbrake.com/Two-Piece-Rotor-Surface-Mount-Slotted-Viper-A-p/2343.htm

P/N 2588 ($959/2 rotors): RB Surfac Mt design for Brembo TA replacement, including the discs (Pad=D1001/60mm depth) - 4 to 6 weeks leadtime.


http://www.racingbrake.com/Two-piece-rotor-Slotted-Surface-Mount-Viper-F-p/2588.htm

Except Stoptech OE replacement (#2218) you can run either 53 or 60mm pads with our wider annulus (65mm) discs.

[Racingbrake]

Here is a detail review of RB caliper and TA rotor metallurgy by MomentaryRacing.
https://driveviper.com/forums/threads/14877-New-kit-under-development-improving-GenIII-IV-brake-balance-for-track-autocross-use?p=236148&viewfull=1#post236148

MomentaryRacing is Wining the race:
https://driveviper.com/forums/threads/14112-Momentary-Racing-completes-SCCA-Majors-weekend-with-2-visits-to-the-podium?p=223989&viewfull=1#post223989

Jon was with Igor at MomentaryRacing during the racing season and he should be able to provide testimonial of RB brakes.

We are proud to be a sponsor of MomentaryRacing to put our brake into real test by torturing them on tracks and compete with other race cars.

RB makes more brake options for Viper (& Hellcat) than all competitions combined (http://www.racingbrake.com/category-s/7328.htm).

No matter you are looking for just replacement or upgrade, standard iron or CCM we have them all.

[esm_viper]

I spoke with Mike at Girodisk today and they are ready and willing to make these for us. Just need some deposits. I highly recommend you call and talk to Mike directly about their products. Very helpfull and knowledgeable.

[Bruce H.]

I spoke with Mike at Girodisk today and they are ready and willing to make these for us. Just need some deposits. I highly recommend you call and talk to Mike directly about their products. Very helpfull and knowledgeable.

Great job for the community! I'm sure others will purchase them also when they need them. Thanks Eric!

[esm_viper]

Great job for the community! I'm sure others will purchase them also when they need them. Thanks Eric!

Thanks Bruce! They seem like a good company with a good product! It's nice to have a more cost effective alternative for guys that are tracking their cars especially since Dodge decided to raise the prices for the stock Brembos. Mike said it was pretty crazy working with Ralph to develop/produce the iron rotors to replace the Carbon rotors that all the Gen V ACR's are switching to. He said people have reached out in the past about the TA rotors but there wasn't enough interest for a production run. Mike also said they recommend the Raybestos pads for their rotors. I'll be ordering a set as soon as we get enough interest to cover the initial deposit for them to start production.

[Racingbrake]

If you are looking for an instant and affordable, swap installation BBK; something better than TA, we have a solution for you that is our 370x34mm* (vs. OE 355x32) oversize rotor kit which we use the same discs as for Camaro ZL1 and CTS-V that's equipped w/Brembo 6 pot calipers, that serious track racers there are in favor of RB two piece rotor upgrade.

Please refer to this thread for more info.
https://driveviper.com/forums/threads/14268-Anybody-tried-the-370-mm-rotor-upgrade?p=329255&viewfull=1#post329255

* Rotor has wider annulus (66.5mm) so you can run TA pad (60mm) or non-TA pad (53mm).

[Racingbrake]

Image of 370x34 BBK Installed

https://cimg2.ibsrv.net/gimg/www.mbworld.org-vbulletin/884x825-1/370x34_kit_e7a391ff9e4d3c2ec4565cfe0fac61c3a8059a0 3.png

Wheel clearance to 18" Sidewinder

https://cimg6.ibsrv.net/gimg/www.mbworld.org-vbulletin/800x1040-1/clearance_d0fad896dfc62acf74c005158508a68d475a8c02 .png

[speedtactics]

Seems like there is no reason to re invent the wheel here, or brake! Looks like RB already did a great job and have several solutions to choose from. Prices are great. Not sure why girodisc would want to do them and what would be the advantage over what is already available and proven?

[serpent]

Image of 370x34 BBK Installed

https://cimg2.ibsrv.net/gimg/www.mbworld.org-vbulletin/884x825-1/370x34_kit_e7a391ff9e4d3c2ec4565cfe0fac61c3a8059a0 3.png

Wheel clearance to 18" Sidewinder

https://cimg6.ibsrv.net/gimg/www.mbworld.org-vbulletin/800x1040-1/clearance_d0fad896dfc62acf74c005158508a68d475a8c02 .png
I wish you guys can make a front kit that rivals Viper exchange's 380mm 6-piston setup (which fit in the Side winder IIs).
The reason I dont like theirs is it has a fat ass aluminum hat. Would be nice if it was painted black so its hard to see.

[Bruce H.]

Seems like there is no reason to re invent the wheel here, or brake! Looks like RB already did a great job and have several solutions to choose from. Prices are great. Not sure why girl disc would want to do them and what would be the advantage over what is already available and proven?

Do we know of any members here who are heavy trackers that have thoroughly stress tested the RB and can report on longevity of the rotors and pad related issues?

[esm_viper]

Seems like there is no reason to re invent the wheel here, or brake! Looks like RB already did a great job and have several solutions to choose from. Prices are great. Not sure why girl disc would want to do them and what would be the advantage over what is already available and proven?

I agree with Bruce, I haven't found much feedback from Viper owners on Racing Brake rotors and track performance. I'm also not crazy about using caliper spacers or grinding down the metal tabs. The guys with ACR's that are switching from Carbon to Iron Girodisc are having great results and I haven't seen ANY negative feedback. Girodisc isn't re-inventing anything, they already have the measurements for the rotor, they just haven't mass produced it because of lack of interest. I'll be getting a set before my next track day in May.

[speedtactics]

They have a solution that does not require any modification and replaces the TA disc and pad. The BBK is the one that requires the spacers and modification. I don't have experience with either jut playing devils advocate here :fpopcorn:

[Racingbrake]

Do we know of any members here who are heavy trackers that have thoroughly stress tested the RB and can report on longevity of the rotors and pad related issues?

...MomentaryRacing to put our brake into real test by torturing them on tracks and compete with other race cars...

BTW anyone here raced harder than Igor of Momentary Racing who represented Viper and competed with other muscle cars?
https://driveviper.com/forums/threads/14877-New-kit-under-development-improving-GenIII-IV-brake-balance-for-track-autocross-use?p=249690&viewfull=1#post249690

Our brakes are serving track racers from Porsches 911 (from 993 to the latest 991), Corvette Z06, Mustang GT350, Camaro G5 ZL1/Z28 and the latest G6 ZL1, Nissan GTR, MB C63, and 700 HP 4700 lbs monster Hellcat.

Among them we think GTR is the community where track guys put different brakes to test; for its weight, speed and popularity, you can search web or this track oriented GTR forum and find out who are there.

http://www.gtrheritage.com/forum/10-handling-and-suspension/

[Racingbrake]

RacingBrakes.com products are amazing!
https://rennlist.com/forums/928-forum/1041893-racingbrakes-com-products-are-amazing.html


Putting on the RacingBrakes.com Rotors on my race car has been one of the best mods yet. now, instead of them cracking out in a half of a season, they last a full 2 seasons
it has to do with their metalurgy and casting methods. (horizontal vs vertical as most common suppliers use). this provides strength and wear consistancy that i havent seen before on any cars i race with.

30540

[LmeaViper]

I agree with Bruce, I haven't found much feedback from Viper owners on Racing Brake rotors and track performance. I'm also not crazy about using caliper spacers or grinding down the metal tabs. The guys with ACR's that are switching from Carbon to Iron Girodisc are having great results and I haven't seen ANY negative feedback. Girodisc isn't re-inventing anything, they already have the measurements for the rotor, they just haven't mass produced it because of lack of interest. I'll be getting a set before my next track day in May.

I have these rotors, but haven't installed them yet. However, I did do a test fit on the driver front and concluded it is best to fully remove the caliper to do the job properly. They will be going on in May 2018, and I will give my feedback after the first or second track event.

[esm_viper]

Look forward to your feedback, thank you! I haven't bought anything yet but need to before my next track day in May.

[esm_viper]

Any interest in the Girodisc TA rotors. I'm ready to buy but they need a few more orders to start a production run.

[parabs]

If anyone doesn’t want to wait I have a set of NEW TA rotors with hats and TA calipers and pads I’d consider letting go for the right deal.

[sharmut]

Any interest in the Girodisc TA rotors. I'm ready to buy but they need a few more orders to start a production run.

I'm not entirely convinced the Girodisc will hold up well over a long period of repeated track use. Saw a set on an ACR-E and the disc developed slight cracking, although not sure how many track miles on the set.
Was under the impression the RB (https://www.racingbrake.com/ProductDetails.asp?ProductCode=DOD-IRK-02) package did not require any modifications. The pad size "ET500 - Street (PD1001-35 & PD1383/968-35)[Included in price]" in their website is confusing. It list the D1001 size(wide annulus) and 968, which I believe is the narrow annulus pad.

[Racingbrake]

I'm not entirely convinced the Girodisc will hold up well over a long period of repeated track use. Saw a set on an ACR-E and the disc developed slight cracking, although not sure how many track miles on the set.
Was under the impression the RB (https://www.racingbrake.com/ProductDetails.asp?ProductCode=DOD-IRK-02) package did not require any modifications. The pad size "ET500 - Street (PD1001-35 & PD1383/968-35)[Included in price]" in their website is confusing. It list the D1001 size(wide annulus) and 968, which I believe is the narrow annulus pad.

You are correct our rotors are made to fit both TA pads (D1001) and non TA pads (D968 or D1383), last 2/3 digits (-35) signify compound.

RB rotors are made with alloyed metallurgy and can last for several seasons because our discs are also heat-treated before machining, so they can deliver a highly consistent brake torque under high heat w/o warping or cracking.

Hardcore track racers review from various tracking communities:

By Porsche 928:
RacingBrakes.com products are amazing!
https://rennlist.com/forums/928-forum/1041893-racingbrakes-com-products-are-amazing.html


RB two piece rotors were voted by Z06 as the best OE replacement (front and rear)
Best 2 pc light weight rotor for grand sport...
https://www.corvetteforum.com/forums/c6-tech-performance/3748239-best-2-pc-light-weight-rotor-for-grand-sport.html

RB is one of the most favorable brake brands in GTR community.

Continued good experience with RacingBrake
http://www.gtrheritage.com/topic/6566-continued-good-experience-with-racingbrake/?hl=%2Bracingbrake#entry115706

[kriskyk]

Patiently waiting for a special delivery from RB :bth_smiley_formula1

[sharmut]

You are correct our rotors are made to fit both TA pads (D1001) and non TA pads (D968 or D1383), last 2/3 digits (-35) signify compound.

Ok I found the section on the website, where the rotor ring part numbers are listed. The ring part numbers are the same for both the front and rear disc.
Replacement Components:
Front Rotor Ring: D403-06-381
Rear Rotor Ring: D403-06-381

[simon455]

Want to bump this thread in case there are still guys interested in TA size girodisc rotors. Mike can make it happen, just need 5 guys

[sharmut]

I was tracking the TA a good amount and couldn't wait for them. Moved on to the ViperExchange BBK package. More leverage and parts are from Stoptech, easy access to replacement parts.

[simon455]

I was tracking the TA a good amount and couldn't wait for them. Moved on to the ViperExchange BBK package. More leverage and parts are from Stoptech, easy access to replacement parts.

I d like to use their acr sized steel front rotors with oem 6 Piston calipers and keep the wide annulus rear rotor size on the back, but the wider face rotors are not available from then yet.

[serpent]

I d like to use their acr sized steel front rotors with oem 6 Piston calipers and keep the wide annulus rear rotor size on the back, but the wider face rotors are not available from then yet.
I believe LMCgrew uses this setup on his acr. He tracks quite often too after seeing his YT vids.
VE bbk for his ACR

Sharmut might be the best person to ask. He tracks both ta and acr.
TA has the VE BBK
ACR is is an ACR-E with gyro rotors I believe.

[simon455]

I’m familiar with girodisc set up on an acr-e, works really well, that’s why im after ta rear rotors to match front (girodisc)
But unfortunately not existant yet. Not looking to do the ve set up.

[sharmut]

The VE BBK price is tough to justify unless you track alot. I don't regret doing it, the extra leverage from the 380mm disc is noticeable.

[simon455]

The VE BBK price is tough to justify unless you track alot. I don't regret doing it, the extra leverage from the 380mm disc is noticeable.

I get really good cost on mopar stuff. I’m not doubting that ve is great way to go for most. In my case, oem stuff is the way to go. Already have most anyways.

[sharmut]

Now I'm really confused, why not just get the OE Brembo disc?

[simon455]

Now I'm really confused, why not just get the OE Brembo disc?

Because it does not match the front 15.4” girodisc rotors aesthetically.
Just to clarify: front oem acr 6 pot calipers, girodisc 15.4” rotors
Rear girodisc 14” rotors with oem calipers, it’s that just 14” wide annulus that would accept the d1001 pad
is not yet produced by girodisc. Only smaller annulus disc that’s identical to oem StopTech rotor
dimensionally is currently available from them.

[sharmut]

Guess availability hasn't changed since I look into a while back. AP-Racing also makes a 355mm narrow annuilus version for the Viper. I have their full set sitting in the garage if someone is interested with matching Raybestos ST47/ST43 pads.

So you want to put the ACR 6-piston caliper with a 390mm disc on the front of the TA and retain the 355mm rotor with 4-piston caliper in the rear.
I see several possible issues.
1) Do you have the wheel clearance in the front? It certainly won't fit in the Sidewinder2. The 380mm Stoptech barely fits.
2) I didn't measure the front caliper bolt spacing, not sure if you need to change the knuckle when changing from the 4-piston TA caliper to the 6-piston ACR caliper.
3) Not sure how much that effects the brake bias.

Isn't the Gen V ACR front caliper a 6-piston monoblock, can't imagine that caliper would be inexpensive.