Hello everyone,

I'm not willing to remove the factory ABS and I'd like to ditch the booster to have better feel. I know that most factory brakes incorporate a crossover. method. This way if one of the master cylinder fails, the cross of front to back will help stop the car. With these units, you get two master cylinders and a cable adjuster. If my theory is correct and the factory ABS is setup with this crossover method, it would make for some sketchy braking with one of these boxes.

Unfortunately, I can't find any information on this and was wondering if anyone has setup a proper pedal box for an Evo 7-9 with factory ABS unit.

I've found this company that makes a setup for us. - https://www.compbrake.com/product/mitsubishi-evo-floor-mounted-hydraulic-pedal-box-kit-sportline-3-pedal-ap-cylinders-kit/

Thank you all!

 

Problem is that the ABS unit regulates the brake bias. I will presume that you want to go to a double master cylinder setup in order to have fine regulation of brake bias? I am afraid it will not work that way.

 

I don't really need adjustable brake bias as I trust the ABS does it's job well. It's more or less getting rid of the power assist that numbs the brake feel and getting the weight lower. I honestly don't know how these pedal setups work and I have only seen the double master on the boxes.

I did look at Bosch motorsports M5 setup. I do wonder if that crossover issue may not be a thing on modern ABS units.




Mitsubishi OEM

 

ABS is the last thing we really need dissected for our cars to understand and control. The best Ive been able to learn is just how to keep it happy with bias and pads. When its not happy, the ABS is really ****ty but when things are right it tolerates some proper hamfisted braking.

 

I totally agree. All the current options require a whole lot of money. However, I've learned setup and drive around it. I feel if you can ditch the vacuum assist and have more pedal feel, ABS will only be on when you screwed up.

 

He's got a point.... This assumes of course that vac is the sole culprit of "ice mode" but I don't believe it is. The wheel speed data still comes into play. Tis why manual is so preferred because you can tune it with your foot wither it's light cause it's in the air or heavy with tons of downforce. But at the club level I agree that ABS is a saving grace, I know lol.

 

Yes, most factory brakes are setup with diagonal brakes circuits, (FR + RL on one and FL + RR on the other) so in the event of a hydraulic failure, there are still 2 corners that work. This is why there are two output lines from the factory master cylinder.

You can still use a dual master pedal box, but instead of being front and rear brakes they will be controlling the diagonal circuits. So you wouldn't need to worry about adjusting a balance bar, you'd just have to make sure they're set even. As for converting to a traditional front + rear circuit setup, I've seen no documentation for the ABS module so you'd likely need to acquire a second module to dissect to see how the internal passages and valving are laid out to see if it's possible. There's also no guarantee that the programming on the module would work for that either.

Also, since we're on the topic. It's not something I've heard of before I found them but Tilton sells ABS specific master cylinders and they claim that high pressure pulsations from abs modules can mess with seals on traditional master cylinders.

https://tiltonracing.com/product/79-...ter-cylinders/

 

For what it is worth, the GrN solution is a small spacer that is installed instead of the OE brake booster (https://www.4turbo.pl/brake-booster-...,3,49895,52110). System keeps stock master, and dual circuit setup, but removes ABS of course as rally cars do not need/want ABS. They also use a dual valve for adjusting the brake bias. If you want to just remove booster, that is the easiest solution. I am doing exactly that. You can always keep the OE ABS but just remove the brake booster.
After you remove the brake booster, messing with pedal box will not gain you much (unless you want to adjust the brake bias of course).

 

You could get one of these kits, https://www.chasebays.com/products/c...bd918452&_ss=r I had one briefly but they are a bit of band aid fix.

I thought the same as you I was adamant I wouldn't get rid of my ABS but now that I have my lap times improved and braking is more consistent, not to mention its very rare i have a lockup and if it is its generally minor. I got the OBP evo specific pedal box kit for mine. It isnt as bolt up as they make out. I think the only thing vehicle specific is the master cylinder sizes. I had to get a bracket made up and welded to the factory floor to fit it. And likely if you were wanting to keep the stock wheel and everything in place youd need to cut and box the firewall so you can sit the pedals far enough forward ( not an issue for me as aftermarket wheel with spacer and the seat is set far back for weight) then youd need to have a throttle cable made up to attach to the pedal as the factory one wont reach.

Need to weigh up why you want a pedal box. They are great for heel toe and general feel and i find you get better control with floor mounted pedals but it would be quite alot of hassle especially if you want to keep your ABS.

If you really like ABS and budget permits look into a Bosch or similar motorsports ABS kit. Road car ABS isnt really designed for circuit work.

 

I don't believe it to be the sole culprit, but It's a factor since the assist helps overpower a quick stab and can make the pedal a bit numb. But Yes, ABS has saved my a@@ a few times and Ice mode isn't too bad from my experience. Nothing like the Corvettes.


I have one I can dissect, I just figured I'd ask on here first. Was hopping someone had done this before. Interesting on the Tilton ABS masters, I'll keep that in mind.

Thanks for sharing this option. I wonder if this would increase pedal effort, since OEM master is design for a booster. This setup is not very cheap and for a bit extra, I would consider a floor mount setup.

Yeah, I would love to go Bosch M5, but the cost is around $10,000 to make ABS and ACD all work. Thank you for your feedback and I really need to consider removing ABS. I was hopping to start with the pedal box to see if I could improve the OE setup first. Looking to move in stages.

 

I think it is stupidly expensive, but can be fabricated. It is a simple piece. I have driven the grN cars and yes, the pedal effort is increased but it is not bad. It has to be said that the stock pedal effort is actually too low for race cars. I have driven some single seaters where max pedal (pedal, not master cyl) force was in the range of 900 N

 

For sure. That can definitely be done for less. I'm not in a position to go pulling the booster off my car right now but if someone can measure things for me I can get a few booster deletes made.

 

I made a solidworks model for the flanges, as I wanted to do it in steel and weld it up, but could do an single piece alloy one too if you want to throw it in a CNC

 

That is interesting to know. Thank you for sharing your experience.

it looks like STM makes one for $50 dollars, it might be worth trying.

https://stmtuned.com/collections/mit...r-delete-plate

 

For sure would be the route to go if you're on a budget and don't mind bending brake lines. I imagine the GrN is the shape that it is to keep the master cylinder in the same spot and work with factory brake lines. If the STM one doesn't require you to lengthen lines you could bend the stock lines to make them fit but otherwise you're making new lines, which isn't a big deal for some people. I'm also not sure what/if modifications are required to the push rod on the pedal either.