MK20 -> MK60 Swap

[heinzboehmer]

Have done some more street driving and a track day now with the MK60, so I'll give some driving impressions. This is all subjective and I'm just some random dude on the internet, not a professional driver, so keep that in mind when reading. I'll split the impressions up into the three separate functions of the system and will mostly focus on comparing it against the MK20.

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Traction Control:

This is the bit that I felt was most similar between the two modules. Traction control seems to come on at about the same threshold and allows about the same amount of spin. The one difference is that the MK60 intervention seems a bit more gradual. On the MK20, you can feel the entirely drivetrain clunking and jerking around whenever power is cut. This feeling is still there with the MK60, but it's less aggressive. Hard gear shifts with cold tires still result in the same level of annoyance when you forget to turn DSC off, though.

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Stability Control:

I'll start with my impressions about the system fully on. It seems like the slip threshold is pretty similar to the MK20. Doesn't really allow you to get sideways at all, but is much more subtle about it. The pulsing felt through the pedal is of lesser magnitude and the system seems to intervene at a higher frequency but less aggressively. All of this yields to less upsetting of the car in a turn. Biggest difference is probably that it feels like the system is intervening less, when in reality it's doing about the same. This is great because it lets you focus more on your driving inputs vs trying to work around the stability control. That being said, the system will still be just as jerky if you truly try to get the car sideways (say, when you take a sharp turn from a stop and break traction), but that's to be expected.

When M track mode is enabled, the slip threshold increases, but not as much as I thought. It seems like it works mostly on wheel speed delta between the front and rear axle. It won't let you get the car super sideways at lower speed, but it will allow slip in corners at higher speeds. I've found that the biggest difference isn't so much in the amount of oversteer it allows, but instead in the amount of understeer. With the MK20, pretty much any steering input with the front end loaded up resulted in the system activating. The MK60 with everything on is much less aggressive at this, but still intervenes a bit (especially at the track). M track mode makes it so that you reaally have to be pushing the front end a lot before it starts intervening.

I've booked an autox in two weeks, so I'll get a chance to test M track mode a bit more there, but that's been my experience so far with it. I will say that I didn't find it super useful on track. It would start getting in the way as soon as the tires warmed up. However, it was nice for catching mistakes in the first couple laps when I thought the tires had warmed up and they hadn't.

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ABS:

This is where I felt the biggest difference (and it was especially huge on track). I do have to give a disclaimer and say that I wasn't the best of scientists, though. I changed three variables at once (MK60, tires, track), so it wasn't truly a fair comparison. Regardless, I felt the difference was big enough that it was worth writing about.

I will probably book a track day at the track I'm most familiar with (Thunderhill East) and take the wheels + tires I was using before (PS4Ss) to run a couple sessions with. This should yield the most direct comparison, but for now, my bad science will have to do.

I can't speak to stopping distances, but I can say that hard ABS braking feels MUCH more controlled with the MK60. When the MK20 was on and I got hard into ABS braking, the entire car would get unsettled and I would have to actively counter steer to keep it going straight. With the MK60, this is no longer the case. I can stand on the brake as hard as I can and the car will come to a stop in a much more calm and controlled manner, no steering input required at all. The system even handles ABS braking with the steering wheel turned surprisingly well. Not that you ever really want to be doing that, but I was messing around with it on track and the car just slowed down as it turned, instead of squirming around all over the place.

Additionally —kinda like with the stability control the feedback in the pedal is significantly improved. MK60 makes the pedal shake at a lower amplitude and higher frequency than the MK20. It's a lot more confidence inspiring and gives the impression that just the unsprung bits are experiencing the effects of ABS and not the entire car. Feeling is much more refined, which makes it feel like you can tell what each tire is doing through the pedal. Probably just something I'm imagining, but it definitely feels like that.

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In conclusion, I'm happy with the swap. The ABS improvements alone make it worth it to me. If anyone close to me has a similar weight MK20 car on PS4Ss, we could do some brake tests to see which one stops better. I have a feeling MK60 will win, but it would be nice to have concrete data

[thegenius46m]

Mk60 vs MK20 is drastic. Id venture to say its the end of 1990s tech vs 2000s to the teens as E9x and later used newer variants of an already drastic upgrade. I haven't driven an MK20 car but have friends with them and the big one is the ability to programmed for brake bias change due to a bbk and/or rack ratio change. Buddy and I both have zhp racks and with M track I can push very hard in the canyons, onramps, on track, etc and the system works very well with little intervention. Friend's MK20 car if he starts to push the car on a simple cloverleaf onramp dsc kicks on full force because of a rack change. So you have those issues and then just the inferior ABS system even with dsc fully disabled, I'd venture to say MK60 is a huge drivability upgrade. Large reason in the early days when I bought my M3 an MK20 car was not an option.

[heinzboehmer]

I have an 818.3 unit and it seems to have a pretty high limit. I have yet to overstep the limits of the ABS or let's say the ABS has a higher limit that me at this point.

My buddy has an MK20 equipped car. I can always out brake him even when the cars were similar. He had a 4.10 diff and I was a little lighter (no cage or anything crazy at that point). Power was about the same.

Nice, sounds like I should notice a big difference then. Excited to try it out.

I also signed up for an autox in a month or so. Will be nice for messing around with m track mode and all that.

[bigjae46]

I felt this a lot on the track, even with stock brakes. Car would get super unstable and squirm around a ton under heavy braking. Thought it was a sticking caliper or bad rotor at first, but I checked that and it was all good. Hoping the MK60 makes the car more stable under ABS braking.

I also agree with what you say about feeling what the front wheels are doing through the brake pedal with the MK60. I've gone out a couple times when the streets are empty to test out higher speed braking (~80 -> ~40) and that was the main difference I noticed. It's hard to describe with such limited exposure to the sensation, but the feedback just feels tighter and crisper. Anyway, I'm sure I'll have more to say about this in a week or so after the track day.

I have an 818.3 unit and it seems to have a pretty high limit. I have yet to overstep the limits of the ABS or let's say the ABS has a higher limit that me at this point.

My buddy has an MK20 equipped car. I can always out brake him even when the cars were similar. He had a 4.10 diff and I was a little lighter (no cage or anything crazy at that point). Power was about the same.

[Nate047]

Cool, yea I have tracked my E36 a lot and experienced what sounds like a similar lackluster, borderline out of control ABS feeling. I'm just assuming the MK20 E46 must be kind of like that? I have only tracked my E46 once so far and I'm just starting to get my build planned out. So TBH, the whole "buy a MK60 car" is not completely off the table. But I kinda don't WANT to do that. I feel like this mod might be inevitable down the road, and I have definitely thought about it a lot before today. But maybe I don't need to come hot out of the gate and do it first. I'm just really not confident in my own ability to putt off a retrofit like this unsupervised. I have an awesome friend who can definitely do this, but that's a biiiig favor to ask someone who's very busy with customer cars.

[heinzboehmer]

Right on, thank you for this. I sent you a DM to see if I can pick your brain and not clutter up OP's thread.

Nah, feel free to keep the conversation going here. Feels like there's little talk about the difference in feel between the two systems besides "MK60 is better", so it's good to be able to read through some of these impressions (even though they're subjective).

[heinzboehmer]

Problem is, the pedal has no feedback, and when you get into the abs, it destabilizes the whole car.

I felt this a lot on the track, even with stock brakes. Car would get super unstable and squirm around a ton under heavy braking. Thought it was a sticking caliper or bad rotor at first, but I checked that and it was all good. Hoping the MK60 makes the car more stable under ABS braking.

I also agree with what you say about feeling what the front wheels are doing through the brake pedal with the MK60. I've gone out a couple times when the streets are empty to test out higher speed braking (~80 -> ~40) and that was the main difference I noticed. It's hard to describe with such limited exposure to the sensation, but the feedback just feels tighter and crisper. Anyway, I'm sure I'll have more to say about this in a week or so after the track day.

[Nate047]

MK20 will work, I have an AP 9668 and AP rear kit. Problem is, the pedal has no feedback, and when you get into the abs, it destabilizes the whole car. On the E46M MK60 race cars I drive you can feel exactly what the front tires are doing through the pedal. That was on Falkens that we run in WRL races. On slicks I expect the MK60 with race map to be even better.

Right on, thank you for this. I sent you a DM to see if I can pick your brain and not clutter up OP's thread.

[eacmen]

I don't know what the MK60 motorsport versions get you specifically, but the Bosch M4 Motorsport kit lets you do precisely that

https://www.bosch-motorsport.com/med..._m4_ait_en.pdf

Contintental has this: https://conti-engineering.com/domain...otorsport-abs/

Apparently based on the "MK100" stability control modules. Perhaps in the past there was a listing for an MK60 variant, but I cannot find them now. Honestly at $7k for a full kit new with software support and tunability... I think that'd be well worth the expense over a $3-4k mk60 "race" kit if I were actually building a race car.

Where things could get interesting is if the consumer variants of those newer modules can be flashed with the respecitve motorsport software without having to pay some guy in Germany a few grand to do it. Contintental RSX = MK100 (and various variants are like $60 on ebay), bosch M4 = bosch 8.1, bosch M5 = bosch 9.0. The bosch 8.1 apparently has an MPC555 CPU, so that might actually be feasible to flash even for us mere mortals if we can get the software dump.

But I digress. Sorry for taking thisthread off topic.

Hopefully CrookedCommie can verify this when he gets his kit. Anxious to see what tuning parameters you get with the motorsport ABS flash!

Tuning ABS could be a dangerous proposition, Done poorly could be unsafe.


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[CrookedCommie]

Gotcha, yea the fronts I am using are also the 345mm. But again that begs the question of how something like a 355mm StopTech for example works with the MK20 ABS. Or older cars like the E36 which has 3-channel ABS, lots of people run BBK of various types on those cars. Just kind of spitballing here. Sounds like you looked into this a lot so I just wanna soak up some secondhand info.

MK20 will work, I have an AP 9668 and AP rear kit. Problem is, the pedal has no feedback, and when you get into the abs, it destabilizes the whole car. On the E46M MK60 race cars I drive you can feel exactly what the front tires are doing through the pedal. That was on Falkens that we run in WRL races. On slicks I expect the MK60 with race map to be even better.

[Nate047]

Doing 996 all around, but will also be going up to the ZCP rotor size. I mean it would work, but ABS wouldn't be working optimally if it thinks the rotors are a different size than what they actually are. ABS is the one thing I do care about on track, so wanted to make sure that was working correctly. I'll likely be getting a ZHP yellow tag steering rack.

Gotcha, yea the fronts I am using are also the 345mm. But again that begs the question of how something like a 355mm StopTech for example works with the MK20 ABS. Or older cars like the E36 which has 3-channel ABS, lots of people run BBK of various types on those cars. Just kind of spitballing here. Sounds like you looked into this a lot so I just wanna soak up some secondhand info.

[tlow98]

Just came in here to say, thank you. Incredible write-up. Something to consider when I drop the entire driveline from my 2002 sedan… consider being the key word. This far more involved than I thought!

[heinzboehmer]

Cool, which brakes are you going with which might not be compatible with MK20? I'm curious because my car is an early '01 MK20 and I am about to jump into my build. I have the Freaky Parts front brakes and 996 rears, I assume you must be talking about something more intense than that but I'd like to hear what you have planned and why it wouldn't work with MK20. I'll probably leave my steering rack alone but I'd like to hear your thoughts on that just for my knowledge base too.

I'm not personally concerned with DSC, or M track mode. I drive my cars either on the street with street tires and not very fast, or on the track with DSC off. What I have read is that ice mode *tends* to not present itself until you are on slicks and using aero, unpredictable freak accident circumstances notwithstanding. And I feel like if I ever get my car to that phase where I'm doing aero and slicks, I can tack on another couple grand to upgrade the ABS, but I probably won't worry about it until then.

Doing 996 all around, but will also be going up to the ZCP rotor size. I mean it would work, but ABS wouldn't be working optimally if it thinks the rotors are a different size than what they actually are. ABS is the one thing I do care about on track, so wanted to make sure that was working correctly. I'll likely be getting a ZHP yellow tag steering rack.

[Nate047]

Cool, which brakes are you going with which might not be compatible with MK20? I'm curious because my car is an early '01 MK20 and I am about to jump into my build. I have the Freaky Parts front brakes and 996 rears, I assume you must be talking about something more intense than that but I'd like to hear what you have planned and why it wouldn't work with MK20. I'll probably leave my steering rack alone but I'd like to hear your thoughts on that just for my knowledge base too.

I'm not personally concerned with DSC, or M track mode. I drive my cars either on the street with street tires and not very fast, or on the track with DSC off. What I have read is that ice mode *tends* to not present itself until you are on slicks and using aero, unpredictable freak accident circumstances notwithstanding. And I feel like if I ever get my car to that phase where I'm doing aero and slicks, I can tack on another couple grand to upgrade the ABS, but I probably won't worry about it until then.

[heinzboehmer]

Nice write up. Appreciate the cheek too lol.
So let me ask the 2 million dollar question(s). How mush was all of this in total? And... Was it worth it? Tell me about the difference in drive experience.

Just added it all up and it came out to right around $2.1k.

• $1100 - new parts (brake lines, clips, gaskets, etc.)
  • I'll get ~$300 of this back once I send all the lifetime warranty parts back to FCP (exhaust gaskets, exhaust nuts/bolts, CSB, etc.)
• $700 - used MK60, wheel speed sensors, brake booster, master cylinder, fluid reservoir and pigtail
• $400 - wiring, PCB and non-M MK20 (used for connector)
  • This was the most unexpected expense because I had originally planned to just splice/solder wires from the MK20 plug to the MK60 pigtail, which would have been basically free. Worth it for the debuggability, reliability and safety though.
• $200 - tools I didn't have (crimper for the wire pins, brake line bender, brake line cutter, etc.)
• $100 - consumables (brake cleaner, shop towels, etc.)

So yeah not exactly cheap. I should be able to sell the MK20 parts and make some of this back, though.

So far, I've noticed zero difference in driving experience. I've only had a chance to drive around town and on the highway a bit (on cold track tires too), so this is actually a good thing. I would expect the car to feel exactly the same during the mundane driving bits and so far that has been the case.

I'm sure M track mode makes a decent difference in the canyons, but I haven't tried it. Friend also recently flipped their car there (everyone was fine) and that has kinda put me off of spirited driving on public roads, so don't expect those types of driving impressions from me any time soon.

Big one is on the track. Going down to laguna seca on the 31st, so I can give my impressions after that. I'll try out DSC fully on, M track mode and DSC fully off. I'm used to driving with DSC off on track (MK20 is horrendous for that kind of driving), so I'll probably just end up doing that anyway, but we'll see.

I do realize that this sorta makes it sound like I spent a bunch of time and money on something that makes no difference to the driving experience, since there's no difference on the street and I don't use DSC on track. I promise I'm not an idiot though (at least not entirely).

The one big thing that pushed me to do this swap is the compatibility with bigger brakes and different steering racks. I plan on doing both of these things soonish (calipers are sitting in the garage) and did not want the MK20 to freak out with those changes. I can code the MK60 for these two things, so the mods should not affect the driving experience negatively.

I've also heard that the MK20 going into ice mode is a decently big problem on track. Never had it happen to me, but still glad to have eliminated that risk.

All in all, I'm not sure yet if it was worth it. It was a great learning experience and it feels good to have a fully refreshed braking system that I can trust, but it was a ton of work. I also have trouble sitting still and not messing with the car though, so I'm sure that played a role in why I decided to go ahead with this swap