Friday, July 17, 2009

Week 5 Update

Saturday July 11th:
Car Dismantling:


Today, we started dismantling the car at 9am. We finished removing the engine at 3am and were out of the shop at 3:30am. We completed all of the major dismantling in only one day. We took out the gas tank, the battery pack, the engine, and parts of the interior. Take a look at our blog to see a time lapse of the whole day! It is an awesome video!
http://mit-evt.blogspot.com/

Sunday July 12th: Final dismantling:
In the morning, I finished removing the rest of the things from the engine compartment and I rebolted the suspension in place so the car can roll. The car is pretty much entirely ready to have new parts installed in it.
Drive Train Revision:
Radu and I had a long talk in the morning about the drive train. The original plan was to put the motor in the exhaust channel under the car and then run a shaft up to the differential. This plan had a couple of serious drawbacks: first, we would have to invert the rear differential which could lead to lubrication problems; second, we would have to cut into the exhaust channel and do body work which is in general a pretty bad idea; third, we would be spinning the differential at 12,000 rpm when the car is going 100mph. After thinking about all these challenges, I thought up another way that we could do the drive train which will probably be a lot easier. My idea is to mount the motor above the differential and have a chain drive linking the two. The chain drive will give us a lot of flexibility with the gearing and the whole assembly will just sit where the old engine was. This plan solves all of the major drawbacks of the old plan but introduces a few new challenges. Mainly, the chain drive and all the mounting. Radu and I both really like the idea and we talked to the rest of the team about it and they also think it is a good idea. I made a CAD model of the whole motor/differential assembly in the evening and I plan to talk it over with the other guys tomorrow.
Monday July 13th:
Mike, Radu, Matt, and I had a long design powwow in the morning about the motor/differential mount. We decided that the best way to do the drive train is to rigidly mount the differential to the motor and then mount both of those to the car through the existing motor mounts and several anti-roll bars. Here is a picture of the CAD model that we finally settled on.
Tuesday July 14th: Motor Frame:
Today I assembled all the basic components of the frame and tack-welded them together. Cutting the compound angles on the cold-cut saw was a little bit of a challenge but Mike had a good suggestion to make angle blocks and it worked very well.
Differential:
I spent several hours calling junk-yards and BMW shops in the area to find a differential that we can use. The Ford 9 inch differential that we have and were planning to use before is too big to fit in the car so we decided to look for another, smaller differential. Because our motor will be outputting so much power, we want a very strong differential so we decided on a BMW rear differential. We would like to get a Limited Slip Differential to improve our handling but it is not critical. I ended up finding a good used transmission at Nissenbaum’s auto salvage very close to the shop. I went over there and picked it up in the afternoon. The guys at Nissenbaum’s were very helpful and were very interested in our project.

Wednesday July 15th: Motor Frame:
Mike and I went in the morning and water-jet cut the front face of the motor mount. It took about 25 minutes worth of cutting time because the steel was 1/2” thick. I welded the entire frame together and fitted the motor and differential into it. The frame itself weighs about 50-60 lbs. With the motor and differential, the frame weighs about 400 pounds.

Thursday July 16th: Differential:
I degreased and repainted the Differential so it is protected and looks good. I sized, lined up, and drilled the hole to mount the differential to the front plate of the motor frame as well as the hole where the shaft goes through the front plate of the frame.
Motor & Differential Frame:
I finished welding the pieces that Matt made for the engine mount cross bar. The steel frame is mostly done. All that is left is to make the cover for the sprockets. Here are a few pictures of the frame. The differential is the black thing on the bottom and the motor is the aluminum cylinder on top. The third picture shows the frame placed in the car. This is how it will look when everything is mounted correctly. The box on the end of the motor is the oil sump. It holds the extra cooling oil from the motor and fits very nicely in the old exhaust channel.

2 comments:

  1. Out of curiosity, why are you guys editing existing posts to do daily updates? Would it be impractical to post separately per update?

    -charles

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  2. I recently came accross your blog and have been reading along. I thought I would leave my first comment. I dont know what to say except that I have enjoyed reading. Nice blog. I will keep visiting this blog very often.


    Margaret

    http://cardrawing.net

    ReplyDelete