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V2 rotor/caliper retrofit for V1 cars

86K views 285 replies 48 participants last post by  AAIIIC 
#1 ·
Front Caliper V2 to V1

Has anybody tried Using the front 6 piston caliper on the first gen cts v? Wheels and Rotors will also be changed out for clearance . Any Information would be great. Long time reader first time posting
Thank you
 
#257 ·
reviving a dead thread. But I'm just curious if anyone has photos of the front v2 calipers and where you have to re-drill for it to bolt on?
 
#258 ·
After being away from my car for a few months, I'll finally be picking it up tomorrow. I plan to install the V2 brakes this weekend using the rotors I re-drilled. In the near future I'll pick up some RB rotor rings for my existing rotor hats for track use.


It's just the mounting holes for the caliper, so there's really nothing to show.
 
#261 ·
Okay that makes much more sense.
 
#262 ·
I finally got around to finishing the job with the re-drilled OEM rotors. At some point in the near future I'll be buying a pair of V2 rotor rings from Racing Brake to put on the RB hats that I've already got, but that can wait for now.

Here's a shot from the back with my cooling duct spindle plate installed.

With that gap in between the center hat and the rotor ring I don't know how effective the spindle plate really is - seems like the forced air has too much of a path to escape.

Caliper installed:


And with the 19" Linea Corse wheel installed:


I need to wash the car so I can get a good profile shot to show off the yellow calipers on the Stealth Grey car.

No real change in feel with just street pads installed. I'm definitely looking forward to seeing how they do on track. With the much bigger pads (~50% larger) and beefier rotors I think they should hold up better to my apparently abusive braking style.
 
#263 ·
A variety of updates since the last time I posted:

- I finally had a chance to get the V2 setup on track. Unfortunately, I only got 1 good session in before the alternator crapped out on me :mad: and I had to swap cars and finish the event in my Subaru. For that 1 session, though, the brakes felt frickin' great! :D

- I just discovered that Centric is now making a V2 front rotor - PN 12062128, only $84 thru rockauto.com. :thumbsup: That's a helluva lot cheaper than the OEM rotors. I was worried that an aftermarket option might not become available because of the design of the V2 rotor (cast iron ring cast around an aluminum center section), so I'm very happy to see I was wrong.

- I've verified that the 18x8.5" Rota Torques will clear these brakes. The Rotas are currently my cool weather setup w/all-seasons on 'em, and I put them on the car this week.

- This probably won't affect most folks, but the Racing Brake center hats are thinner than the OEM center hats. As a result, you lose a couple millimeters of caliper clearance (to the back of the wheel spokes) when you install the RB rotors. So, if you're running a set of wheels with tight caliper clearance (like the used set of CCWs I bought and ran for 1 session on track), you might find that you can't run the fancy 2-piece rotors because the ~2.5mm of clearance just became ~0.5mm. :eek: Fortunately, it is not an issue with the Team Dynamics track wheels.
 
#269 ·
- I've verified that the 18x8.5" Rota Torques will clear these brakes. The Rotas are currently my cool weather setup w/all-seasons on 'em, and I put them on the car this week.
BLAM! :D



The picture makes it look like clearance to the barrel of the wheel is tighter than it actually is. There's a bit of lip at the back of the spokes, then it drops a bit to the actual barrel, so there's plenty of clearance (even with balancing weights near the backs of the spokes). Clearance from the back of the spokes to the face of the caliper is huge.

On another note, at the Cadillac V-Series Driving Lab at Circuit of the Americas in early December, they had a Brembo engineer dude there to tell us about how awesome the Brembos are, etc etc. My particular group of participants was mostly full of enthusiast types, which the Brembo guy recognized - "I see a number of personal helmets in the group here..." Instead of just giving us his standard spiel, he opened the floor to questions so we have a more technically oriented discussion. Afterwards, I approached him and asked about getting V2 rotors made with the V1 hub bore and bolt pattern. He said it might be possible to do a batch that way if there was interest, since the aluminum center hat is initially solid and then the bolt pattern and hub bore are machined in. I still need to follow up on our discussion - he told me to contact Brembo USA and give his name as a reference. I'll post up if anything comes of that.
 
#264 ·
Well, here's the thing that I don't understand. Apparently, many have been installing the V2 calipers with Z06 14" rotors on F-body's, with the Z06 rotors the exact same dimensions as our OE rotors, only 5 lug. Here is an article where Scoggin-Dickey provided the parts combination of V2 calipers and C6 Z06 rotors:

http://www.gmhightechperformance.co...brembo_brakes_nitto_tires_wheels/viewall.html

Are you absolutely sure installing the V2 calipers on the OE 14" rotors is impossible?
 
#265 ·
I'm assuming the offset of the caliper relative to the rotor due to the mounting holes causes insufficient overlap of pad and rotor. That is just a guess, so until someone tries it that's just speculation.

AAIIC maybe you could test this out?
 
#266 · (Edited)
Oh, sure, play on my incurable desire to figure this sort of thing out, even when I should be something productive like replacing my alternator. :p Fortunately for you I have one corner of the car already jacked up, the wheel off, and a couple sets of V1 rotors sitting here to play with.

V2 caliper on V2 rotor. Pad material rides maybe 0.5mm inside the outer edge of the rotor:


V2 caliper on V1 rotor. I didn't measure it at all, but the pad material overhangs the outer edge of the rotor by ~1/4". That makes sense, as the V1 rotors are 355mm and the V2 rotors are 370mm.


Closer view (albeit a little blurry):


Inside diameter matches up just fine:


I may have to experiment with this next track season. I think that, for my purposes, the greater thermal mass of the V2 rotor is key to getting the better braking performance that I want on track. However, I'm curious if the larger pad area, which spreads the heat load a bit, would be enough to help the brakes survive the abuse I subject them to.

It's worth noting that there's not a whole lot of selection in pads for the V2 caliper as of yet, and what is out there is substantially more expensive than the V1 pads (which are common to STIs, Evos, 350Zs, S197 Mustangs, etc etc). Not using a chunk of those expensive pads is kind of a shame, but obviously using the V1 rotors does make life easier.

Edit: I just sent an email to Centric via their "Contact Us" page.
me said:
I noticed the other day that you are now offering front rotors for the 2nd generation ('09+) CTS-V (aka "V2"), part number 120.62128. That's fantastic news, as the OEM rotors are very expensive.

A number of folks, myself included, have installed the V2's 6-piston calipers and the larger rotors on our '04-07 1st generation CTS-Vs (aka "V1"). The biggest hurdle to doing this is figuring out the rotors, as the V1 uses a larger center bore and has a funky 6x115mm bolt pattern vice the 5x120mm pattern on the V2. I had a machine shop enlarge the center bore of a pair of OEM V2 rotors, and then re-drilled the hub bolt pattern by hand - definitely not the preferred solution!

I wonder if it would be possible to produce a version of the 120.62128 rotor using the center bore and hub bolt pattern from the V1's 125.62075 rotors. No other changes to the design would be necessary; I am currently using those modified OEM V2 rotors on my V1 using the V1 front knuckles and V1 wheel bearing/hub assemblies. Everything lines up perfectly.

I realize that this is probably not an application your company would normally produce, but I figured it could not hurt to ask. I think a significant number of V1 owners would undertake the V2 rotor/caliper upgrade if an affordable rotor solution was available.

Thank you for your time!
 
#267 ·
This is great information. I wonder if there is still benefit running the v2 calipers and v1 rotors.
 
#268 · (Edited by Moderator)
Thank you for taking the time to go through and document this, really, thank you! Before seeing this, I was contemplating getting the V2 calipers to use on the V1 rotors as in the thread that I posted. I am surprised that SD would suggest this parts combination when they clearly do not match up, especially when SD has such a stellar reputation.

Good idea asking about the V2 rotor, however, it may be easier to ask for them to produce blanks rather than have them drilled for a specific application. There would be sufficient demand, especially since the V2 calipers are being installed across platforms as indicated in the GM High Performance thread that I linked. You could even point them to this thread in an attempt to catch their attention. I believe the only platform the V2 shares the wheel bolt pattern with is the G8.

Thanks again!

----------

Following AAIIIC's lead, I sent Centric an email as well. I figure the more of us that do will only show there is sufficient demand for such a thing.



my email said:
I have noticed that you now offer the 2009+ Cadillac CTS-V front rotors. While you may or may not be interested in this, I would like to ask if it would be possible to purchase these rotors without the center eccentric or wheel bolt pattern machined in the hat of the rotor for aftermarket use.

The V2 (the designation for the 2009+ CTS-V) front rotors are quite popular across many GM platforms due to their six piston calipers and relatively low price (around $350 each). However, the V2 rotors have a somewhat unique bolt pattern which forces many to use the smaller 14" diameter 2006+ (C6) Z06 front rotors.

I personally have a 2004 Cadillac CTS-V (a V1) and would like to upgrade to the V2 rotors as well. However, the V1 front rotors are the smaller 14" diameter as well.

To show you there is sufficient market for a rotor blank, I have a included a V1 to V2 caliper upgrade thread from a board (of which there are many) that has grown to 16 pages and been viewed almost 15,ooo times:

http://www.cadillacforums.com/forum...219790-v2-rotor-caliper-retrofit-v1-cars.html

Here is a magazine article from GM High Performance where they installed teh V2 calipers with 2006+ Z06 rotors on a 2000 F-Body Camaro:

http://www.gmhightechperformance.co...brembo_brakes_nitto_tires_wheels/viewall.html

If you were to make this a reality to the market, i'm sure that you quickly realize the market potential.

Thank you for your time and consideration.
 
#271 ·
Interested and yes v2 calipers clear v1 oem wheels.
 
#273 ·
A few random notes:

(1) First, an install note that I don't think I covered previously. I know it has been mentioned that the V2 uses larger diameter caliper mounting bolts (14mm vs 12mm). The V2 bolts are actually a bit too long (in other words, the V1 knuckle isn't quite as thick as the V2 knuckle where the caliper bolts up). As a result, the OEM bolts will actually touch the back of the center hat section of the OEM V2 rotors. I initially shaved the bolts down a few millimeters, but that resulted in some ugly threads on the end, so they didn't thread into the calipers by hand very cleanly. I have a thread chaser set, but the only 14mm chaser is the wrong pitch, so I couldn't clean up the threads as I would've like. So, I went to Fastenal and bought 4 grade 10.9 (same as the OEM bolts) 14mm-2.0 x 45mm bolts. (The stock ones were ~49 or 50mm long.) They work perfectly; you could just go straight to that option rather than ordering the OEM V2 bolts. I suppose the other option would be some thick 14mm washers under the head of the V2 bolts - I'm sure there's a reason I didn't go that route, but I can't remember it now. :p

(2) I finally got to do a full track event with the V2 setup and I came away very happy that I went through all this effort. I don't have any objective data to refer to, but the brakes felt great and I never once felt I needed to take it easy for a bit to let the brakes recover. When I still had the V1 setup, the lead instructor at one of the events asked me about the brakes and how they did with such a heavy car. I told him that with my Subaru [normally aspirated, thus slow, and obviously much lighter than the V], I can go deep into a braking zone and even though I'm braking very hard, there's still more there. If the guy ahead of me slows down more than I expected him to, I still have braking power left in reserve. But with the V, I always felt like I was using all the braking capacity I had, and it just wasn't as confidence inspiring. Obviously, others find the V1 brakes to be more than enough, but that's how they felt for me on track.

With the V2 brakes, I feel as though I have that reserve now. Going into turn 1 at VIR (upper 130s down to ~45mph) I was able to take some late point-bys, take the inside line, and comfortably haul the car down.

(3) I'm out in the garage putting the street rotors & pads back on and figured I'd post up some weights:
OEM V2 rotors - 25#
Racing Brake 2-piece V2 rotors - 23#

(4) I'm still curious about what rotor options are out there. As I've previously mentioned, Centric now offers a rotor for the V2 - #120.62128. I haven't found an actual picture of one yet, but on RockAuto.com it says it's co-cast (like the OEM rotors), and the weight is about the same as I just measured for my OEM rotor. (If the Centric part was not co-cast, I would expect it to be quite a bit heavier since the center hat would be cast iron rather than aluminum.)

Rockauto.com also has two different varieties of ACDelco front rotors - 1-piece #1771105 (co-cast rotor, corresponds to GM part #25851237), and 2-piece #1771145/1156 (corresponds to GM part #20795300/302). The 2-piece rotors are "only" $297 on rockauto.com, which is pretty damn good. I'm curious if the rotor rings are intended to be serviceable, or if they're basically "throw away" 2-piece rotors. I've done a bit of searching around today but haven't found any info on that yet. If they are replaceable they would be a helluva lot better deal than the RB option!
 
#276 ·
The 2-piece rotors are "only" $297 on rockauto.com, which is pretty damn good. I'm curious if the rotor rings are intended to be serviceable, or if they're basically "throw away" 2-piece rotors. I've done a bit of searching around today but haven't found any info on that yet.
A guy over on cadillacowners.com says Brembo does not offer replacement rings. I would think a V2 owner or ZL1 owner would've figured out how to source replacements through Coleman or TCE or someone like that, but I haven't seen any sign of that in searching around.

Have you driven on the V2 caliper+V1 rotor combo yet? I'm very interested in this setup as an interim to buying the full up RB 2 piece rotors
Although I said earlier that I might give that a shot, I don't think I'll get around to it. As expensive as the V2 track pads are, it seems kind of foolish to not get full use out of them. I suppose I could try it with my street pads - if it ruins them, I won't be all that upset, as I'm not too impressed by them.
 
#274 ·
Have you driven on the V2 caliper+V1 rotor combo yet? I'm very interested in this setup as an interim to buying the full up RB 2 piece rotors
 
#275 ·
Glad this got bumped up today as I just opened up the box with my nice new shiny V2 calipers. I haven't decided which route to go yet with the rotors.
 
#277 · (Edited)
Random update:

When I installed the V2 stuff, I didn't find much in the way of street pad selection for the V2 pads. I ended up going with Hawk HPS. They've been OK, but hardly anything to write home to Mom about. And even a single stop from high speed (quick blast on the highway or something like that) was enough to make them give up the ghost. I was getting increasingly unimpressed by the HPSs, so I decided to look into other options.

Looking at options on rockauto.com I discovered that GM actually offers two sets of pads for the V2. There's the OE Brembo pads, PN 25940447, which have a ~$450 MSRP, but there's also PN 19288002. MSRP on that pad is only ~$70, and you can get them online for about 2/3 of that. (I got them from rockauto.com as ACDelco 17D1405M (Durastop Professional semi-metallic)). For that minimal outlay (less than 1/3 what the Hawk pads cost!), I figured it couldn't hurt to try them out. I'm glad I did. Their performance is worlds better than the HPSs. Still no noise (which was also true of the HPSs), but much, much better initial bite, overall stopping power, and they seem to be able to take a little heat. The only unknown is dust - the HPSs were very non-dusty, which was one good thing about them. Before I installed these pads I had already switched over to my "hyperblack" Rota winter wheels, so it's hard to tell how dusty the ACDelco pads are.

I also picked up a set of Raybestos PGD1405M Professional Grade semi-metallics. They were shown on rockauto.com as a "Wholesaler Closeout", and came in NAPA packaging. I imagine I'll keep the ACDelcos on for now, and maybe try the Raybestos pads in a few months, just to compare. Again, for $25 I figured it couldn't hurt to see how good/bad they are.
 
#278 ·
any clues on where you found them for $25?
 
#282 ·
Re: v2 calipers on v1????

Looking into doing a caliper upgrade on my 05 cts v i read somewhere you can do the 09 cts v calipers. My biggest concern is will the stock wheels clear the calipers?
thanks guys
Allow me to merge your post into the "V2 rotor/caliper retrofit for V1 cars" thread that was literally the top thread in the Performance Mods forum when you decided to post a new thread.
 
#283 ·
Bump for some brake rotor updates. I initially did my conversion using the original OEM 1-piece "co-cast" rotors. Then GM started offering the 2-piece Brembo rotors, so I've acquired a few sets of those over the past few years. Regardless of whether you use the 1-piece or 2-piece V2 rotors, if you intend to use them on V1 hubs, you have to enlarge the center bore (from 67.4 out to 70.7mm), and you have to redrill the bolt pattern to get your 6x115.

Recently, as I was browsing around for brake parts, I discovered something kind of curious. The V2 2-piece rotors are ACDelco 177-1145/1146. I thought that the ATS-V used the same brake setup as the V2, but it turns out the ATS-V has different part numbers for the 2-piece front rotors - 177-1193/1194. According to the specs I can find (clicking the "INFO" button on each part on Rock Auto), they're the same size - 370x34mm - so that made me wonder about the different part numbers. The only thing I can figure is that the hat offset is different; that's one spec that isn't listed for both rotors on Rock Auto (it shows the ATS-V rotor "height" is 2.4", but height isn't listed for the V2 rotors). Someone on LS1tech pointed me to centricparts.com, and sure enough, the specs they list there show the ATS-V rotors have a 10mm different offset (more on that in the pics below).

Similarly, some V7 Vettes (the '15+ C7 Grand Sport package) also run a 370x34mm 2-piece Brembo rotor. It's slotted, but apparently isn't directionally vaned, as I'm only seeing 1 part number - 177-1174. Based on the centricparts.com data, the offset of the GS Vette rotor is the same as the V2 rotor.


I ordered 1 of each of the GS Vette and ATS-V rotors so I can compare them to the V2 rotors I've already got. In the case of the ATS-V rotors it's basically just for the curiosity's sake, as the rotors (at this point) are more expensive than the V2 rotors. The GS rotors are also more expensive, but if someone wants slotted rotors for the V2-calipers-on-a-V1 setup, then the GS rotors might be a way to get there.

I received an ATS-V rotor and a couple of GS Vette rotors and pulled them out of the boxes for a look.

- The ATS-V rotor hat visually has more offset than the V2 and Vette rotor hats. The rotor ring appears identical to the V2 rotor ring, with directional vanes.

- The GS Vette rotor hats appear to be the same offset (to the naked eye) as the V2 rotors, so that's good. The rotor ring is non-directional; it uses pillar vanes that look very similar to the original co-cast V2 rotors (this style). I have a couple of those co-cast rotors that I picked up last year when Amazon was doing the 20% off ACDelco deal, I'll have to pull one out and compare side-by-side with the GS Vette rotor.

Most importantly (for my purposes, sticking with 6-lug hubs), the GS Vette rotor hats have the same center bore as our V1 hubs (testing with an old hub I've got with all the studs knocked out). That makes modifying the rotors to fit the V1 a much easier/cheaper evolution, as I don't have to pay a machine shop to enlarge the center bore of the rotor from 67.4mm to 70.7mm, and instead just have to redrill the bolt pattern. That's something I'm able to do myself.

As of today the GS Vette rotors (ACDelco 177-1174) are ~$15ea more expensive than the V2 rotors (ACDelco 177-1145/1146) on Amazon, but that cost difference is more than made up for by not having to pay for machining. And as many of us have seen, the price of ACDelco stuff seems to bounce around quite a bit on Amazon, so in a few months the Vette rotors may be cheaper. (Or the V2 rotors may be $75ea cheaper instead of $15, who knows?!)

Some comparison pics.

First, ATS-V vs GS Vette rotor. Centric's catalog said there's a 10mm difference in offset, and you can see that pretty easily with the naked eye:


The GS Vette rotor with one of my modified V2 rotor hats:


Visually they look like the same offset, which jives with what Centric's catalog says:


And a straight edge across the two looks purty good:


Here you can see that the GS Vette rotor has the same type of non-directional, pillar style cooling vanes that the original V2 co-cast rotors have:
 
#285 ·
AAIIIC,
Thanks for all the great info. Sorry for reviving a very dead thread, but this is good stuff.
I’m looking to install V2 brakes on my gen1 SRX. If I’m understanding this correctly, I should go with C7 GS rotors (drilling them out for the 6 lug pattern), drill out the mounting bolt holes to accept the larger bolts, but I’m unclear as to what the best solution is to address the slight offset between caliper and rotor? Additionally, I understand there are some additional hurdles with the rear brakes?
Any help would be appreciated!
 
#286 ·
Funny that you've bumped this thread, because I've just finally revived this topic myself. (y) After posting all that info back in 2017, I really hadn't done anything with the rotors, because I had some modified V2 rotors on hand for track duty and was able to use those through the 2018 track day "season". In 2019 I didn't get to any events, and this year I haven't done any events ... until next weekend. I had used up the V2 rotors, so it was time to figure out using the Vette rotors. This evening I installed my modified V2 hats onto the Vette rotor rings; I still need to drill the 6x115 pattern onto the Vette hats, so I'll then have 2 sets of hats with the proper bolt pattern.

AAIIIC,
Thanks for all the great info. Sorry for reviving a very dead thread, but this is good stuff.
I’m looking to install V2 brakes on my gen1 SRX. If I’m understanding this correctly, I should go with C7 GS rotors (drilling them out for the 6 lug pattern), drill out the mounting bolt holes to accept the larger bolts, but I’m unclear as to what the best solution is to address the slight offset between caliper and rotor?
I'm not sure what offset you're referring to. (I say that without remembering what I may have typed here in the past :p.) Everything should line up fine. The only thing I can think of is that I have brake cooling ducts installed, and those sandwich between the hub and knuckle; the aluminum is thicker than the steel ABS wiring bracket that was originally sandwiched in there, but that little difference hasn't impacted anything.

Additionally, I understand there are some additional hurdles with the rear brakes?
The V1 and V2 rear brake setup is the same (other than the obvious bolt pattern difference). I installed the V2 rear calipers just because I wanted the matching yellow calipers all around. I can't speak to any hurdles on the SRX, like if the parking brake is a different size or something like that.
 
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