Sunday, January 24, 2010

Seat Brace

One of the items we needed to address for the next race was the seat. To be in accordance with the rules the seatback must be restrained from going backwards. In many cars the harness bar will serve this purpose but in the Civic the harness bar is about a foot back from the seat with an average sized driver. We snuck through tech the last time by having the seat back a bit further than normal. Not wanting to risk it again, we decided to get a brace installed.

The off-the-shelf solution is a bar like the one from I/O Port Racing:

The I/O Port model is aluminum and ~$90. Being cheap we decided to make one at 1/2 the cost and about 4x the weight. We bought some telescoping steel tubing from McMaster-Carr and welded up some scrap. Here's the result:

Friday, January 22, 2010

Sway Bar

The Civic sedans didn't come with a sway bar from the factory. There's not even a place to mount it. We got the rear swaybar from the Integra when we swapped out the rear brakes and lower control arms. It's a paltry .5" in diameter. It was suggested that we need something like 1000 lb/in rate at the wheel. The stock Integra bar is closer to 15 lb/in.

Fortunately the front sway bar from a Jeep TJ is about the same length as the Integra bar. It's also 1-1/8" in diameter. Since torsional stiffness is related to diameter^4, the Jeep bar will be over 25 times stiffer than the Integra bar. Of course it's lever arm is also longer, so that reduces the rate by a square factor.

We couldn't find a place to make it fit underneath the car, so we mounted the bar to the cage and used some tubing to connect it to the wheel. I think we ended up with the right balance between hoopty and clever for LeMons.


We were all ready to put the transmission back together when we had a scary realization: the LSD isn't going to fit. After doing a little research we discovered that the S80/Y80 transmissions had slightly different guts depending on whether they were bolted to a B18B (non-vtec) or a B18C (vtec). The B18C transmissions got a different final drive gear, pinion shaft and different bearings. The final drive gear is on a different bolt pattern than the B18B version, so we can't swap our final drive gear onto the B18C LSD.

We were basically left with three choices:
1) Put it all back together with the old diff and give up on our dream of LSD.
2) Buy a final drive gear and pinion shaft (~$800) and turn our transmission into a B18C version.
3) Get an OBX LSD (~$350) for the B18B and sell our B18C OEM LSD.

#1 is unacceptable after all this effort. #2 blows our budget. That leaves #3. We heard enough scary stuff about the OBX during our research that we went with the used OEM unit in the first place, but now it's looking like the only option.

Wednesday, January 20, 2010

Almost Famous

Murilee put us in his LeMons Legends post!

Link here!

Saturday, January 2, 2010


So we've finally started to make some progress. We ordered a used limited slip from Japan on eBay. We were pleasantly surprised that it actually showed up.

We found some YouTube videos that make it look pretty easy to put in. The first video shows how to take the open diff out. The second shows how the limited slip differential goes in, and the third shows how to put the transmission back together.

Evans Tuning Video 1
Evans Tuning Video 2
Evans Tuning Video 3

So we pulled the motor out and got to work. While the motor is out we'll take the opportunity to modify the motor mounts. When we first put the motor in we noticed it came close to the front radius rods that run from the lower x-member to the lower links of the front suspension. Lowering the front x-member on spacers fixed the problem but created a new one. The reduced caster makes the car feel a bit more squirrely. Moving the motor up .5" will allow us to put the geometry back to stock.

Here's what the inside of our transmission looks like.

The videos are great, but they assume that you're doing the job right and not "the LeMons way". They used new bearings and bolts. We're going to use the old bearings and cross our fingers because we don't want to spend another $70. You'll notice that the old differential has sealed bearings and the LSD that came has tapered roller bearings. We'll need to press the bearings off and put them on the LSD without destrying them.

Mark also took the time to take the puny front anti-sway bar off. We need a stiff one at the rear to let our front tires have more grip. Hopefully we can find something off a bus.