octagondd

 

If you're driving your car right now with the stock booster in place without the vacuum assist please don't thing it's the same thing. It isn't even close. There are parts inside the booster that need to be removed and/or modified to achieve what I'm talking about. I only know this because we had to do this to a friends CRX race car 20+ years ago when his booster developed a significant leak. Overnight we gutted it and I made some metal parts to replace some rubber stuff in it. The next day he said it had the best brake pedal feel EVER... even though it wasn't exactly legal. We also left it like that for the rest of the time he owned the car.

The only thing removed from my brake setup is the vacuum from the original engine. The pedal was very stiff, but worked well. One day I opened the brake fluid fill canister and since then my pedal has been a little spongy. I probably need to bleed the lines to get the stiffer pedal back.

Right now I have unboosted manual brakes. The car is light so it doesn't take much to stop, but I have used the e-brake on occasion. I do have a vacuum pump, but haven't installed it yet. I am sure it will be noisy, but I also ordered an extra tank to hold some vacuum so I have immediate power brakes without waiting for the pump to spool up and so the pump doesn't have to turn on every time I hit the pedal. I have added some rubber to the mount to try to isolate the pump from the body, but may also need to make a box for it to keep the sound down. Right now I have lots of road noise because of the holes in the hatch for the battery boxes aren't sealed up yet. I think I am going to try the expanding foam to seal them, but am concerned about the foam squeaking as the body and boxes move while bumping down the road.

I also ordered some Integra calipers and rotors, but Pepboys said they didn't fit the knuckles. I haven't had a chance to look at that myself yet. I may need Integra knuckles and steering rods.

Ah, the same way you would do it with the normal engine then. Thats cool.

Yes, only difference is no engine braking when letting off the accelerator. Basically like being in neutral. Just loss of energy from rotational losses and friction. Also, you must use parking brake to park. You can't put it in gear on any slope and have it stay. It just rolls.

Cool......I worked in the Electric Car biz for 2 years, did a full electric conversion on a Chevy Equinox for GM......But I worked mainly on the mechanical design and prototype build side of things.

 

Anyway, how are you shifting gears without a clutch??  I haven't read your blog so forgive me if the answer is in there!

 

Rob

Basically, I just hold the shifter lightly against the next gear and as the rpms come down from the previous gear, it slides in. Down shifting is a bit tougher since it requires giving a little boost to the rpms with the accelerator, then it slips into gear. 

This is not optimal from a fast shifting/performance or even safety perspective, but simpler for me since adding the clutch disk/flywheel complicates the motor coupling a bit. This car is mainly for commuting and was never intended for performance, so not your usual project on this forum. After doing the project, I now wish I had kept the clutch.

I didn't do a whole lot of calculations since I didn't know how to. I found an EV calculator and learned how to use it, but it didn't have any curves, just static numbers at speed. Mostly, I went by what others had done in the same car. I was originally shooting for as much efficiency as possible, but now that I am up and running, and have plenty of range, I want to play a little more. Part of my issue is I could get a controller with more power output and that would help, but changing the gear ratios could also help. I realize this will then change my rpms, but that is fine.

I am running (44) 3.2 volt cells in series for 140.8 volts. I usually use first through third gears. The motor likes to be between 2500 and 3500 rpms for power, efficiency and cooling. It is recommended not to go over 5500 rpms, which is convenient since this is the red zone on the 86 HF rpm gauge. In 3rd gear going 60 mph I am at 3200 rpm. At 70mph I am at 3700 rpm. I also have 15" tires which make my speedo show about 2mph high at 60 mph or so, but the numbers I gave are the actual speeds and not the speedo.

I believe I have an High Altitude transmission based on the numbers I saw in another thread here. When I plug those gear ratios into the EV calculator it is matching what I see on my rpm gauge.