1991 Accord LX Race Car

[ukemike]

So on friday 2/23 we passed our tech inspection with no difficulty, as usual. When it came to BS inspection, this is where you get your class assignment, we got a new guy. He looked at the car a bit and asked about our history. I told him in 18 races we were usually in B but have never finished well enough to win C. He asked which class I wanted to be in and I said, "I don't care. We're here to have fun." He put us in C. So naturally we decided to send it. Usually we fuel at the track pumps, which is far slower than hot-pitting. We decided to hot pit. This is decidedly riskier for the car, since you can't check fluids or do anything but fuel and driver change. Dennis went first on Saturday. He started about 45th which is random and only has to do with where you are when it goes green. He worked his way into 16th overall and 1st in C class! But no one knew because the scorekeepers made an error and had us listed in B. We decided that we'd tell them about their error on Sunday and only if we were still doing well. I went second and after the driver change we were in 30th.

The car was great. I'd put a lot of work into drag reduction. Thunderhill has long straights and fast corners. I figured there was time to be found in aero. I blocked the grill above the bumper from side to side. I made vortex generators to improve attachment of the boundary layer to the rear window, and I fashioned a small spoiler on the back corner of the trunk with roofing flashing. I dialed back the angle of attack on our wing. I made side panels for the splitter and ramps to direct air over the front wheels which do stick out a bit. I didn't have time to do any underbody work, which is where the biggest gains can be found, but I hoped that we'd see higher straight speeds and more stability in corners.

Sure enough our data acquisition showed us about 7mph faster on the longest straight and we were all getting about 6 seconds a lap faster. That's huge. Of course there were weather differences and we used a Hankook RS4s instead of our old reliable Falken 615Ks, so was it all aero? Who knows.

The car is janky as hell when going slow. It's noisy and hard to control, but on the track at speed we handle as well as any car out there, and with our LSD we get corner exits that make even the very powerful cars work hard to get around us.

I worked us back up to 14th overall and 2nd in C. C class or not this was already our best performance yet. My son Ewan drove next and he had an off that he self reported and later got a black flag for contact that didn't happen. With those he finished us in 24th overall. Jason did the last drive of the day and worked us back into 4th place in C. By the end of the day the car was shaking and the brakes were weak. So we jacked it up and found that the driver side axle had some play in it. We were loosing a CV joint. When these start to go bad it goes from okay to undrivable in about 8 laps so we were lucky it didn't happen during the race. We went to replace the axle and broke a breaker bar on that axle nut. Since I had a spare knuckle too we gave up on the nut and took the knuckle and axle out together. BUT! The box that I thought contained my spare driver side axle, actually had a failed old garbage axle. So I got on the phone at about 7pm calling parts stores all around the area. I found one in Red Bluff that had our axle and sent Dennis north to get it. Meanwhile we bled the brakes. When he got back around 9ish we installed it all and went back to our motel rooms. I was in bed about 11:30pm.

We did the reverse driver order Sunday. So Jason went first. He got us to 15th overall and 2nd in C when the car leading C burst an oil cooler line and caught on fire, a little. It was an old ford ranger done up as a Cybertruck. Red flag means everyone stops where they are and waits while emergency crews deal. When that lifted Jason's time was up so he came straight in. They were up by three laps so we didn't officially pass them until 3 laps into Ewan's stint. In the mean time the '68 El Camino passed us while we were in. So Ewan started 2nd in C and 17th overall. The El Camino got 2 laps up on us. When they stopped about 30 minutes later it was very dramatic. They pitted and Ewan made up a lap and was coming around as they finsihed. They were leaving pit lane as Ewan started on the front straight. He caught them on their out lap and put us in the lead in C. Ewan had an off just a few laps into his stint and we dropped into 3rd in C after the El Camino and some toyota corolla in daewoo drag. But got us back into 2nd. When I went out for my drive the El Camino was immediately on my butt. This was the reverse 3 mile which I have never driven. So while learning the track I managed to keep him from passing, which would have put us another lap down, and started to put some distance. I started making excellent headway when it went south. Some bonehead in an e36 318Ti got hard onto his breaks approaching turn 8 which is a flat out kink. I cannot figure out why he got on his breaks but I piled into the back of him, and flatspotted my right front tire badly. I came into the penalty box and lost a place. Back out there the car shoot at high speeds very badly. I finished the last 30 minutes of my drive and came in. We changed drivers and fueled. I told Dennis to come into the paddock where we would change the tire, but he decided to try it first. After 1 lap he came in and we changed the tire and sent him. After that we held onto 3rd in C and finished in 16th overall. The other axle failed as we were parking the car at home that night. There was minimal body damage from the crash.

It was by far our best finish ever. All our video is posted on youtube.

You can watch the crash here: https://youtu.be/xBHQihZp7hw?si=JetaI5cHp6sYUh3C&t=4517
You can watch a crazy series of passes I made after a full course yellow here: https://youtu.be/KwhxRiP76Q4?si=B1cNTHqN45e2UPeg&t=2965

[SSMAccord]

This sounds like a very exciting race. I’ll be watching the YouTube links. Congrats on your best finish yet!!!

[Raf99]

Thanks for the vid & updates! Love the clock on the floor of the car. I always am disconnecting my battery and so having a clock in the car is a past luxury.

[ukemike]

Our next race is going to be Buttonwillow in September. Buttonwillow has a loooong fast right hand sweeper, so aero could give us a substantial advantage. My hopes for upgrades for the race are:

• cleanup the underside aero with flat panels under the engine, the gas tank area, and leading to a very simple rear diffuser
• reduce drag around the open windows
• replace my el-cheaparoni ebay dual element rear wing with a real single element rear wing (probably also from ebay)
• build a new front splitter with splitter diffusers and that meshes with the flat bottom

I'd better get started. That's a lot to do.

[Raf99]

So when you speed up in this long right what does the car do?
I know with 400HP you can control the understeer with the throttle. But I'm assuming you have understeer?

My thought was focus aero where needed....

[ukemike]

It's pretty balanced now. At low speeds it's understeer for sure. I like a tiny bit of understeer at high speed because it is predictable and gives confidence. I think people underestimate confidence in corning speed. The work I did on aero before the last race really paid off. Turn 8 at Thunderhill is fast. When we first raced there I was afraid to take it without lifting at least a little. At this race I was able to take it without lifting AND WITHOUT even using the whole track. I could take an inside line or outside line, pass in the corner, and carry that crazy speed all the way up the next straight. It was so much fun to sail past cars with significantly more power but less grip or less confidence. I want MORE of that! There are no aero rules in lemons and few teams do more than a wing. I feel this is a place I can exploit. Undertrays are one of the few win-wins with aero. They reduce drag AND reduce lift. Usually reducing lift (or increasing downforce) is done at the cost of more drag. Our car is underpowered so drag is very bad. So underbody is a big want. But if I want it to stay balanced I need to improve on the front and rear equally.

But mostly all of this is because I'm a mechanical engineer. My favorite courses were fluids and aero. I'm just having so so much fun with it.

[Raf99]

Oh well... you're set. I say "shark fins"! The antennas of course, lots of them. Well a line of them... on the roof. Ok .... front spoiler fins.

[ukemike]

It looks like we have a CB7 showdown at Buttonwillow shaping up. That_Wood_CB7, Aventari, and I all are looking at the Buttonwillow 24hours of Lemons Race on the last weekend of September. I don't know if everyone is 100% confirmed, but we're all working on it. At the last few California Lemons Races there have been Honda Meetups on Saturday night. If we can arrange to get neighboring paddock spaces we could host the Honda meet.

[ukemike]

Aero


I've been working on the aerodynamics of the car for weeks now. The best improvements come from undertrays, but the biggest pain comes from working under the car. So I've been working on the second biggest source of drag. The windows. Lemons requires that the windows on the front seats be open. Open windows create a lot of drag. There was no reason that the rear windows need to be open. But in lots of cars, just one or two open windows causes buffetting. No one likes that for 90 minutes straight. So there were lots of things to consider.

I replaced the rear wing with another wing from ebay, but this was from Megan Racing and the wing element is an actual aerofoil it looks like a low speed low drag aerofoil. I haven't yet added the second element, and for Buttonwillow I may not. I don't want too much drag, it's a fast course.

I also made sections that cover the top of the front window. I read one account where blocking the top section of the open front window reduced the drag caused by that window by about 30%. I hope the judges won't make me take those off. (I just got word from Lemons officials, my partial front window coverings are not allowed.) :-(

I made deflectors that should redirect the air away from the window opening. (I'll have to improve those to extend to the top of the windows to make up for the other bits being banned) On the driver side I made an opening in the deflector that should direct air at the driver. Out of flashing I made some surfaces that mount on the B pillar part of the front door window, that should help air re-attach so it flows smoothly over the rear windows. To address the possible buffeting I cut two NACA duct openings, in reverse into the rear fenders. It turns out that NACA ducts in reverse are good at extracting air from inside. Makes sense to me. So any turbulence at the front windows will have a pressure release in the rear.

For the under tray, I also used cardboard aided design to make a mockup. I bought some sheet aluminum and I have plans in my head, but all that work is still ahead of me.

[ukemike]

Solid Motor Mounts

Last race we were having some trouble shifting into 3rd coming out of hard right hand turns. My motor mounts are stock and they get a lot of wear. I wanted an upgrade so I bought some 3m Urethane windshield adhesive. The hardness of this urethane is hard for a rubber but softer than urethane bushings. I injected it into the void spaces in the new motor mounts and let them sit for weeks to fully cure. Of course that makes it sound easy. Nope. Urethane windshield adhesive is the messiest stuff ever invented. If you let some start to dry on your skin, only time will remove the stain. Brake cleaner gets it off but brake cleaner is not good for you. Last weekend Ewan installed them for me while I was working on the aero.

These will be considerable harder than the stock ones, but will still be pliable. I am not a believer in solid or overly hard mounts. When you take too much flexibility out of a system it will find some new way to shake by breaking something. The front mount has urethane inserts from Energy Suspension. The rear mount is still stock. Getting to it is a monumental undertaking. I hope these fix the shifting problem. Regardless they’re cool.

[ukemike]

Windage Tray!


For a while I’ve had a windage tray that I got from a picknpull. I haven’t put it in before because it’s a long slog of unpleasant work. You have to take off the 2-1 exhaust pipe. Access to several exhaust bolts is a big pain. You have to remove two bolts and a nut on the front, 2 nuts and bolts at the back, two on the back side of the engine block, one hanger, and the oxygen sensor. Every one is tricky and you’re on your back and my whole system is a little stressed due to less than perfect install of my exhaust. You have to remove the longitudinal cross member too. It’s trivial to take off but getting it back on is a struggle.* The exhaust and the cross member run right under the oil pan. It turns out you also need to take off the dust cover on the bottom of the transmission. Finally you can take off the oil pan which is messy, so you can put the tray in and do all it in reverse. I ended up using the oil pan from the old engine. It doesn’t have a dent in the bottom. It doesn’t sound like much but it took me most of the weekend. I had wanted to make a baffle to prevent oil starvation on long left handers, but I was completely unprepared for that, no materials, no design, no time. I actually believe that the windage tray will help with that. The tray sits very close to the oil pan and the oil level. With the tray I don’t have to worry about the crank whipping the oil, so I can safely over fill it. More oil means less likely to starve.

Why am I concerned about oil starvation when we have never had that problem? The answer is downforce. With the undertray and the real wing, I hope we will be able to corner faster that we have in the past. I saw a youtube of another team that added a wing to their Honda, and starved of oil in a long turn and spun a bearing like 10 laps in.

Anyway I got it all done, with fresh oil and filter, in time for dinner.

* I figured out a trick to make it easier. Maybe writing it here will help me rememeber next time I need to do it. You loosen the bolts on the forward transverse cross member and that gives you the slack to get the bolts in.

[Raf99]

The cars of the 60s-70s would have a rear deck lid window vent that would allow smoke to escape under the window and back out another vent in the trunk. Are you allowed to cut holes on the rear deck lid, like a big hole from speaker to speaker? To allow air to pass through?

And shocked you don't run a baffled pan...

[ukemike]

The cars of the 60s-70s would have a rear deck lid window vent that would allow smoke to escape under the window and back out another vent in the trunk. Are you allowed to cut holes on the rear deck lid, like a big hole from speaker to speaker? To allow air to pass through?

And shocked you don't run a baffled pan...

If the vents I put in the rear quarter panels aren't enough to prevent bufffeting, I plan to hole saw a 3" hole where the license plate would be in a street car.