Progress has been made!
A huge part of the LMP360-EVO development is about improving on track safety. Infact it will be over half of the ~$5900 budget increase on the car. It’s not that the car as built is unsafe. The cage is Legal, harnesses exist, and there aren’t shady undersized parts in the suspension. But between rules requirements and my own personal desires improvements need to be made.
A FIA FT3 bladdered fuel cell has previously been in the car and it will simply be re-installed. Additional fuel system modifications are planned (AN type fuel lines) but they are really a secondary level of change and may not occur until after a few events.
A on board fire system will be installed as well. This is required by the Gridlife Rules for the class the car will run in and generally Fire = Bad.
The last big area of safety improvements is infact the first one I will address and that’s Brakes.
The current braking system on the car is:
Front: Donor car sourced Pads/Calipers/Rotors from 2002 Outback. These are 2 piston sliding calipers with 294mm rotors.
Rear: Donor car sourced Pads/Calipers/Rotors from 1996 Impreza. These are Single piston Sliding calipers with 250mm rotors.
Lines: Jegs Universal brake line kit with braided stainless hoses. An3->banjo adapter fittings and a Brake Bias Valve in the rear brake line.
Pedals/MC: OEM Subaru Outback pedals and master cylinder. Pedal assembly is inverted with pushrod extended to mount MC in front of inboard shocks. Booster removed and manual ratio pushrod hole drilled.
So there are some issues that I don’t like. All the brake components are old and the pads are really bad. At the FIRM I got fade pretty bad after a lap which resulted in incredibly long braking zones and generally not pushing the car. The OEM dual circuit master cylinder has 2 additional ports that are currently plugged with correct thread bolts but I don’t like having these extra ports just there. The OEM master cylinder is not properly biased and sized for front and rear disc brakes with this weight balance. There is not sufficient rear brake bias for the car, the bias valve only allows the rear pressure to be reduced, not increased. The modified brake pushrod makes me nervous. It’s way overbuilt but it’s modified. Brake components really shouldn’t be modified.
So what’s the plan:
Front: New stock replacement 2002 Outback 2-piston Calipers and 294mm Rotors. Hawk 9012 pads. The Outback brakes are common diameter to WRX parts with only a small difference in caliper size. “Track” pads are available for these calipers so there is no reason to change to the “WRX” spec calipers.
Rear: New stock replacement 2000 Subaru 2.5RS 2-piston Calipers and 277mm Rotors. Hawk 9012 pads. Again the 2.5RS stuff has readily available track pads but is more pedestrian in price then more exotic options. This will be a HUGE improvement in rear brake torque available and heat sink compared to current.
Lines: Re-use the Current Lines
Pedals/MC: Wilwood 340-16603 pedal assembly with remote reservoir master cylinders.
I knew I wanted to put a aftermarket pedal set in the car. I have experience with the Wilwood pedals and MC as that is what is ran in the MG. I was happy with how easy to mount the Wilwood pedal set was, and they have provided 5 years of good performance with no issues so I knew I wanted to use Wilwood stuff on the LMP360. The MG uses reverse hung pedals and the LMP360 would need floor mount pedals so I needed to do some information gathering. I talked to the Wilwood reps during PRI to see what was available and what would work best. When I told them what car it was for they had already seen the car on display and wanted to be a part of the project.
I provided them specs for the calipers and car weight and CG and a week ago a big box of shiny engineered performance parts arrived.
So now I need to put them in the car.
The front of the chassis is a bit of a crowded space. The inboard shocks take up most of the top of the firewall, and because I wanted as long of arms as possible the inboard pivots for the suspension are in the way as well. The high floor limits the amount of space under these components as well.
It was a hard needle to thread but the angle grinder came out and made some space. I cut out the current footwell cross member so the master cylinders can occupy the space where the 2x2 used to live. This will all get plated back in and should be at least as strong as it was before.
The clutch master cylinder will have to be mounted “remote” from the pedals. The pedals are just low enough that a extended pushrod can be used to actuate the clutch. This pushrod will go just beneath the inner suspension pivot.
I had hoped I wouldn’t have to modify the pedal assembly itself in anyway. I unfortunately will end up having to remove the upper clutch master cylinder bolt and boss from the pedals. This bolt would actually be coincident with the suspension pivot. However the brake master cylinders and actuation will be entirely Wilwood with no modification, extensions, or shenanigans. Just installed per their instructions which honestly is the most important part.
I'm very excited for the improved confidence I will have in the revised brakes on the car.
Huge thanks to Wilwood for supporting the build.