When upgrading E8/9 to X Brembo front, - upgrade rear too?
 

Howdy,

I am helping friend optimize his Evo 8 MR for track.
The motor was built, 2.0 Manley typical and effective rods & pistons,HKS 274/278 cams + HKS springs, and HKS 7460 turbo, full exhaust - Tomei downpipe and Fujitsubo catback.
Nice responsive reliable package.

5 speed transmission was swapped in, and fresh new OEM clutch.
Ohlins are now used.

He is running out of brakes: we used DTC70 pads, and he forgot the cooling ducts, but despite good brake fluid, on E85 car is fast and could use more braking power.

So we are going for Evo X front brembo/stock rotor setup.

Does anybody match the front X upgrade to rear X upgrade?

Or do you leave rear OEM E8/9?

Thank you.

I dont see much of a need to upgrade the rear. I at least haven't ever run out of heat capacity there. We're just starting to get into playing with brakes though going with smaller piston area and larger rotors to change some of the bias. There are differing thoughts here of which end needs more power, but my AutoX experience says there rear needs more power or the front needs less.

We leave the rear's Evo 8/9, and I pair the DTC70 front with the DTC60 rear.

You are affecting the balance between the front and rear with switch to setup from X, so make sure your computer will be able to control it. When I had OEM fronts and AX6s in the rear (swapped just front pads), car was undrivable on my next autoX event. Basically, at normal temps AX6es are pretty mild and close to OEM. Because of that, driving on the street was not an issue. But, after first half of the run, rears got enough heat and I had hard time finishing that run. On the second run, issue was obvious right from the start and I just took it easy and parked the car.
Luckily, you have lots of choices with pad selection for the track and I would consider getting a bit more aggressive option for the rear to start with.

Gents,

Thank you.
We'll proceed with fronts only, unless the seller decides to give up rears at too good of a deal to pass up.

My friend will never AX, he goes to local San Francisco tracks, favorite by far Laguna Seca, than Sonoma, and Thunderhill.

Front brakes take 80% of the brunt: at Laguna he's under the bridge at about 120+mph, a into turn 1 flat out to 130mph, hard-braking into turn 2 -which is about 40mph turn.
The MR is full weight about 3350 + him in full gear: 3550 lb total. On 295/30x18 Toyo RR.
Some sessions are 30 minutes, lap times are low 1:40, so its maybe 18 laps total: currently he's out of brakes after 2 laps- having to drive lap or two cruising just to allow brakes to recover.

jeez. what's his brake setup right now? hope the X's do what he needs them to, would love to hear a report after.

What are you going with instead?

gotcha. i'm hoping not to need one either - dunno what caliper u went with, but i moved from 9 setup to 10 setup in front for the extra 30mm in rotor, and also got the vented ss pistons from racing brake + ti shims. hope it's good

I'll report how X swap goes, and yes, he did not install ducts which probably would have helped delay the fade.
He runs OEM Brembo and DTC70 front pads.
Full weight, sufficient power on E85, good driver, means he stresses brakes, but ducts were big omission.

Nice to hear options like vented pistons and Willwood Aero6 caliper.