Well the preseason starts as soon as the season ends when it comes to car development, and there are a number of things going on with the Evo. This preseason will be all about improving the balance of the car – namely, decreasing weight and/or shifting the weight balance. As far as events go, it’s a little trickier with some significant life changes ahead, and I may only make it out to the track once or twice for the 2022 season.
The TLDR: Passenger seat was installed, completing the front set: ~16lbs off the car for both seats combined. The ACD & battery were relocated to the rear, ~35lbs off the front and onto the rear. Front and rear uprights were installed, 10lbs saved up front, 7lbs in rear, plus massive suspension geometry improvements. Ceramic wheel bearings installed, for longevity and lower friction. Strut tower brace, UICP & turbo inlet were installed, saving 5lbs from the front of the car. AP Racing brakes were installed, saving 14lbs from the front of the car. That’s a total of 52lbs off the car entirely, with 64lbs off the front end of the car (and 35lbs to the back), approximately 1.5% shifted back. Should be a decent improvement dynamically. Once the wheels arrive, that will be another 8lbs or so off the total of the car. I was thinking about going back to softer rear springs at the end of the season, but I think with adding back so much balance to the rear of he car again, the 12k rear spring may behave a little better.
Passenger seat: I was able to grab the driver’s seat a little bit “early” but the passenger’s seat took a whopping 10 months due to supply chain issues. Even then, I got lucky as I heard part of the boat flooded, and my seat was in a set of boxes that was above the water line… Paired with the driver’s seat, this should net about -16 lbs total closer to the front end of the car.
Minor suspension tweak: I raised the front suspension about 7mm or so (10mm of preload, 3mm decreased at the bottom for easier access to the adjustment knob. I’m also lowering the rears by about 5mm, for an improved suspension geometry. And, a hair of weight balance shifting back.
Other/Misc: I had an oil leak post-engine swap that was handily fixed by RS when I brought the car in for the ACD pump & battery relocation. I also had the car retuned by Ronnie, for a full 91 oct/E85 map, bumping it up to 25psi. I also opted to swap the Omni4bar map sensor for the JDM/Evo X map sensor, for reliability purposes.
ASM: Finally, I took the car to ASM to get a few miscellaneous issues handled. I had an odd coolant leak, evidenced by a little bit of coolant on the trans and t-case. Another shop had said it looked to be the head gasket, but RS said they had machined the head, and should not be related to the head gasket, and to check the hoses for leaks. Based on what ASM found, it turned out to be the upper rad hose clamp. They found it by pressurizing the system and wiggling hoses. Seems to have fixed the problem here. We also mounted the battery to an actual tray in the rear as the solution done by RS was not to my liking. Finally, we aligned and corner balanced the car as well. Was very eager to see how the weight distribution ended up with all those changes.
Per below, with about a quarter tank of gas, the Evo now weighs in at 3,116lbs. The last time the car was weighed, it came in at 3,263 (without a driver) – with a full tank of gas. Adding back about 63lbs for gas, that puts the Evo at 3,179 lbs – 84 lbs lighter than it was before – and about 30lbs lighter than I estimated. I’m not sure where the additional weight savings comes from – I’m sure some of it is from not running a balance shaft any longer, and some other minor changes.
Regarding the balance, the car is back to a 60/40 split (61/39 with a quarter tank, full tank will go to the rear). That’s a solid improvement, as it was getting close to 63/37 – and about double the 1.5% rearward shift that I had originally estimated.
I’ve also pulled about half a degree of camber from each rear side, to get closer to -3 degrees of camber for the rear. For now, will leave the front as-is.
There have been a LOT of preseason updates this year, and really hoping I’ll get a chance to dial in all the changes we made.