Aston Martin DB9 BBK Retrofit for E46 M3 Review

The Aston Martin DB9 BBK Retrofit for E46 M3 is a new set up that I have been testing for the last few months. A few months ago we did a guide to do an Brembo E31 retrofit on the E46 M3, but this one is slightly different. Both are 4-piston calipers, but the calipers can be bought for a little cheaper than the E31. Nonetheless this retrofit is not very well known in the community, but it sure is a great one. I first came across the idea from Milla Bimmer on E46 M3 Owners Only Club on Facebook so a big shout out to her for letting me know about the kit. If you’re interested in the market to upgrade your brakes, but don’t want to spend thousands on a new kit, take a read.

What’s great about this setup is that the calipers do not require any machining and the adapter kit includes an upgradable bracket that allows for either stock 325mm or 345mm CSL rotors to be used. You will need the VagBremTechnic kit which costs about $260 USD shipped. VagBremTechnic is based in the UK and supply very high quality adapters and brake lines. From UK to California, I received my kit in 2 days upon ordering from them. This means no rust rings since the design fully sweeps for both rotor setups. The fitment is pretty much perfect and you can tell that detailed attention was paid to the machined parts. The piston sizes are well matched to the stock brake system with only about a 1.7% piston area decrease, meaning that the pedal distance/feel will feel extremely OE. It also retains the more of the stock brake bias with 40/44mm pistons compared to the much smaller 36/40mm pistons in the 996 front calipers. Technically, its a tad bit more front biased than stock brake bias than the 996 setup.

We are getting a lot of comments on the article’s lack of emphasis on brake bias or too much emphasis on brake bias. These are my thoughts, I have tried out rear bias and front bias before in the past as well as mixing pads to adjust bias via the coefficients. There isn’t anything wrong with oem brake bias or shifting bias to rears or front per say. As long as you can adjust compression and adjust your braking threshold to compensate. It is important to note balance is key at the track. Professional drivers will want adjustable rear bias before rears break traction to maximize braking zones but this is more of 10/10 driving all out. For majority of HPDE drivers, a neutral or slightly rear is preferred to maximize driver confidence instead in order to improve lap times as you will have a bigger buffer zone for mistakes while still having the ability to trail brake effectively. A setup that has too much front bias will induce understeer characteristics but a slight front bias would behave the same as stock bias. Either way, you can mix and match pads with different coefficients to get it just right. But for the general street setup, you want as OEM as you can get. -Oscar

Front Bias: High understeer characteristics

Slight Front Bias: Slight understeer characteristics

Stock Bias: Slight understeer characteristics

Slight Rear Bias: Neutral

Rear Bias: Snap oversteer characteristics

Bias Comparison (Calculator Courtesy of CLAWHAMM3R on m3forum):

Update 8/30/2019: User Mr. T-Rex suggested the calculation used for CLAWHAMM3R’s formula included a 54mm front brake pad and not a 61mm pad, which it seems, therefore the stock ZCP ratio should be 1:76. This is not confirmed.

1. 345mm DB9 + 996 Rear = 68.52% Front 31.48% Rear
2. Stock M3 + Stock M3 Rear = 66.87% Front 33.13% Rear
3. 325mm DB9 + Stock M3 Rear = 65.89% Front 34.11% Rear
4. CSL Front + CSL Rear = 64.37% Front 35.63% Rear
5. 996 Front + 996 Rear = 64.06% Front 35.94% Rear
6. 325mm DB9 + 996 Rear = 63.91% Front 36.09% Rear

Front:  2004-2009 Aston Martin DB9 4 Piston or Audi TTRS 8J 4 Piston or Audi RS3 8P 4 Piston

Rear: Porsche 996 Base

Aston Martin DB9 calipers can be found on eBay for about $250 per caliper used or about $466 new on parts stores. If you scout eBay enough, you can find them for dirt cheap on the used market. You can also use Audi TTRS 8J model or RS3 8P model but you will have to flip the calipers since they are reversed from Audi.

The downside running the 345mm setup is that 345mm CSL are soft and do wear out quicker than most. You may need to replace them more often, but lucky for us, FCPEuro has lifetime warranty. OEM 18” wheels will require 16mm spacers per side for a 325mm disc, and 12mm for a 345mm disc. Unfortunately, there is no 355mm rotor pairing for this kit. If you want to upgrade from 325mm or 345mm rotors, you need to get the VagBremTechnic kit for the AP Racing 362mm rotors. This 362mm kit is quite costly and may not clear 18” wheels. We believe that optimal rotor size for the track should be 345-365mm; any larger may not yield much more benefit.

OEM 18″ wheels require wheel spacers:
On the 325mm disc a minimum of 16mm per side
On the 345mm disc a minimum of 12mm per side & be cautious of wheel weights.

My Current Setup

• Aston Martin DB9 Front
• Porsche 996 Rear
• VagBremTechnic Kit + 345mm CSL rotors
• Carbotech XP12/XP10 track pads
• Endless brake fluid
• Titanium brake pad shims

Caliper Performance

I went to test this setup at Streets of Willow on 10/28/2018 and was extremely pleased with the performance. Upon first lap, I noticed that the linear braking was drastically improved. I was able to extend in a much later braking zone over my previous E31 BBK setup due to larger rotors and pad size. There was zero brake fade and braking stayed consistent throughout all my sessions thanks to Endless brake fluid. When paired with Hankook TD C30 tires, I was very confident to brake at an excess of 1G, according to my Aim Data. I didn’t notice any pad knockback despite pulling close to 1.77Gs while cornering. I believe the titanium shims helped with reducing the amount of piston travel needed to contact the pad again. The increased rotor size of 345mm dissipated heat well and with just hints of glazing. The floating nature of the 345mm aided in weight reduction and made the vehicle more responsive to steering inputs.

This is by far my favorite retrofit setup with the 996 rears and is highly recommended for a budget BBK system. In comparison to the stock 325mm rotors, the 345mm CSL rotors are well worth the price in exchange for performance. Aesthetics-wise, these look visually bigger than the 996 front calipers as well. This setup has both form and function in my opinion.

Parts List

Below are the parts list for the DB9 retrofit. There are links included with pricing information, however we suggest you shop around with the part number (if given) to get the best current market price. As a side note, the DB9 part number has two X’s at the end. These are variable letters depending on the color of the caliper – the part is the same. If you want to see the parts list for the Brembo 996 rear caliper, check it out on our Brembo E31 996 Big Brake Kit article.

Aston Martin DB9 Calipers

As listed on Vagbremtechnic’s site, below are some of the available brake pads but not conclusive:

• Pagid Road Front Brake Pad Set (T3132)
• Mintex Road Front Brake Pad Set (MDB1859)
• Mintex M1144 Race Front Brake Pad Set (MDB1859M1144)
• Mintex M1155 Race Front Brake Pad Set (MDB1859M1155)
• Mintex M1166 Race Front Brake Pad Set (MDB1859M1166)
• Ferodo DS2500 Race Front Brake Pad Set (FRP3067H)
• Ferodo DS3000 Race Front Brake Pad Set (FRP3067R)
• Pagid RS4-2 Race Front Brake Pad Set (E2487RS42)
• Pagid RS29 Race Front Brake Pad Set (E2487RS29)
• Project Mu H16 Race Front Brake Pad Set (F906-H16)