4-Piston Caliper Conversion for Over $145.00

[357]

I'll be jumping head first into the world of brake upgrades in a few days when I start designing the caliper brackets for my recently acquisition. The plan is to fit the entire braking system outboard of the flex lines from a Lancer Evolution IX on my '91L (under 17's, of course). System specs are as follows:

Front:
320x32mm rotors
46/40mm Staggered-diameter 4-piston Brembo calipers
Hawk Performance HPS pads

Rear:
300x22mm rotors (yep, bigger than the fronts on a stock 164)
40mm diameter opposed 2-piston Brembo calipers
Hawk HPS pads

The caliper adapters will be, to say the least, big, given the 39mm and 49mm rotor diameter increases for the front and rear, respectively. Current plan is 7075-T7351 aluminum (hugely better mechanical properties than 6061-T6 -- this stuff is true aerospace-grade aluminum), if I can make the bracket thick enough, and without threads. If not, I'll probably go with 17-4PH stainless. Equipment should arrive sometime later in the week, so I'll be able to post some initial pics, and I'll continue to do so as the work progresses. I'm expecting cost for all four corners to be in the $1200-$1500 range, but that's because I'm doing my own mechanical design, FEA, and machining.

Should be a fun project, and definitely a great learning experience.

Will keep you guys posted.

-Fred

[Alfisto Steve]

Quote:

Originally Posted by 357 I'll be jumping head first into the world of brake upgrades in a few days when I start designing the caliper brackets for my recently acquisition. The plan is to fit the entire braking system outboard of the flex lines from a Lancer Evolution IX on my '91L (under 17's, of course). System specs are as follows: Front: 320x32mm rotors 46/40mm Staggered-diameter 4-piston Brembo calipers Hawk Performance HPS pads Rear: 300x22mm rotors (yep, bigger than the fronts on a stock 164) 40mm diameter opposed 2-piston Brembo calipers Hawk HPS pads The caliper adapters will be, to say the least, big, given the 39mm and 49mm rotor diameter increases for the front and rear, respectively. Current plan is 7075-T7351 aluminum (hugely better mechanical properties than 6061-T6 -- this stuff is true aerospace-grade aluminum), if I can make the bracket thick enough, and without threads. If not, I'll probably go with 17-4PH stainless. Equipment should arrive sometime later in the week, so I'll be able to post some initial pics, and I'll continue to do so as the work progresses. I'm expecting cost for all four corners to be in the $1200-$1500 range, but that's because I'm doing my own mechanical design, FEA, and machining. Should be a fun project, and definitely a great learning experience. Will keep you guys posted. -Fred

[357]

I think I'll be OK with the stock master cylinder, at least for initial testing. The net force applied by the front Evo calipers with the stock MC isn't so much more than the stock calipers that it will be an issue, i think. It's about a 27% increase, yielding a 44% increase in front brake torque due to the larger rotors. If I'm not mistaken, Jason has tried the 24V front calipers with the 12V master cylinder (a net clamping force increase of ~14%) with no ill effects. That being said, I'll probably go to a slightly larger MC sometime in the near future, in order to gain back some of the pedal feel lost with the larger caliper piston area.

Admittedly, I'm not sure of the balance in back, since I don't know the stock rear piston diameter. Hopefully the area is around 20% greater than stock. That would yield factory brake balance, albeit with 44% more stopping power. Ultimately, I'll adjust the rears with a proportioning valve, if they're not where they should be alone.

[peglegtom]

Won't the greater volume required to move the larger pistons result in increased pedal travel with the stock MC? You may run out of travel before you get the maximum braking force. I think 17-4PH is an excellent choice for the bracket, as you could make it much thinner than the 7075-T7351 aluminum (and yes, I am a Metallurgist and know what these alloys are). You would need a much thicker bracket in aluminum to compensate for its lower modulus, which negates some of the weight improvement. The only problem with 17-4PH is that is is difficult to machine, even in the solution treated (annealed) condition, and the requirement that it be precipatition hardened after all machining is completed. It would also offer increased corrosion resistance in comparision to the aluminum. If you do have to drill and tap, I would not recommend any aluminum alloy.

[357]

Yeah, definitely no structural threads in Al. If aluminum does end up being the optimal choice, I'm now thinking 2024 might be a better choice, given its higher fracture toughness. Regarding the precipitation hardening stainless, how much more difficult is it to machine than a 300-series material? My machining experience with stainless is pretty much limited to 303, 304, and a bit of 316, so I'm not really too familiar with working the harder alloys.

I'm not really entirely sure what the effect will be on pedal travel, to be honest. Common sense says that yes, the travel will increase by a percentage equal to the increase in the piston area. At the same time, though, there's not really any compliance to speak of in the hydraulic system once the pads come into contact with the rotors (which, in my understanding, is basically instantaneously). If the pistons aren't actually moving during most of the braking, then, the pedal shouldn't really move any more than it does already (i.e., the compliance in the system is coming from somewhere outside the hydraulics). Unless brake fluid is actually compressible, but I didn't think any liquids were.

Anybody have any first-hand experience with this issue?

[357]

Hardware! Pictures!

Sorry it's taken so long, and for the grainy photos, but I finally got a chance to take pics of the new stuff going on the car! I'm also in the process of looking for a warehouse to rent with a few other guys from work, in order to have a better space to work in, so the brakes (in addition to the upcoming engine rebuild) may wait until that gets settled.

The other thing I'm realizing is that my biggest technical challenge won't be fitting the brakes to the car, but rather, what to do about the hand brake. The Evo uses a shoe-type brake, where the 164 has a mechanism to mechanically actuate the existing brake calipers. Don't yet know what I'm going to do about that one.

But for now, here's what's sitting in my living room:

Front calipers:


Front rotors:


Rear calipers:


Rear rotors:


Hubcentric wheel adapters:


Wheels and tires (17x8 5Zigen FN01R-C's shod with 225/45 Nitto NT-01's):

[Mike164S]

what size thickness did you end up making the adpaters?

[Grant]

Yes, where did you source the hub adapters?

Also, I think the other posters were right in saying that you may have to address the piston/pedal travel issue. You might only engage the brakes just before hitting the floor.

If it's not a daily, might as well put everything on and see how it goes w/o a MC change?

[Grant]

If you really like sporting driving with the growl of the Alfa V6, another car you might want to consider is a GTV6 or Milano. Try one out some time!

[357]

The 19mm adapters were sourced from Custom Wheel Service of Anaheim, CA. Currently, the car is sort of a back-up daily driver for my '07 Nissan Frontier. Once the warehouse gets taken care of, the 164 will be parked, and the Frontier will once again be my daily.

The pedal travel issue will definitely need to be addressed, but I'm sort of curious to see how well (or poorly) the stock MC handles the big pistons.

I've been looking more at a Milano lately, actually. Mainly due to the limitations of front-drive, since I like the look of the 164 better than the Milano (although it's growing on me), and much much better than the GTV6 (don't know why I've never taken to it really). Ideally, I'd have a 155 Q4 to turn into a track car, but those are just a bit rare here.

[Grant]

The Milanos grow on you. I think it is very attractive now yet my girlfriend hates it.

I think the GTV6 should be more capable on the track and hold their value better, but racing a 4 door has a certain appeal that I have trouble getting past.

Be warned though, a Nissan S14 or something similar can be made to go a lot faster for a lot less money! We can talk more via PM or make a thread in the Milano section if you're interested.

[Rorysbrown]

Solve your rear hand brake issue by using the stock rear calipers. Honda uses Brembo front calipers only on their Brembo equipped cars. I personally have Brembo calipers off a JDM Honda RSX-R on my Civic Type R with stock rears and it works great.