Lightweight FC Doors
Thread Starter
Joined: Mar 2004
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From: Houston
Lightweight FC Doors
Hi guys,
First and foremost, this modification is "race-only", don't do this to your daily driver and then blame me when you die.
Here is something I've been working on lately. I've been on a mission to drop some weight and started working on the doors. This weight is without any wiring, no window motors, no door panels, no glass (putting in lexan), the "webbing" all gone, as well as the side impact brace.
If anyone feels compelled to go out and weigh a power-window door, I would greatly appreciate it, since I didn't get a stock form weight. I eventually got the weight of each door down to ~27lbs.
First pic is the scale "zero'ed".
2nd pic is with a 33lb weight.
3rd pic is with door.
First and foremost, this modification is "race-only", don't do this to your daily driver and then blame me when you die.
Here is something I've been working on lately. I've been on a mission to drop some weight and started working on the doors. This weight is without any wiring, no window motors, no door panels, no glass (putting in lexan), the "webbing" all gone, as well as the side impact brace.
If anyone feels compelled to go out and weigh a power-window door, I would greatly appreciate it, since I didn't get a stock form weight. I eventually got the weight of each door down to ~27lbs.
First pic is the scale "zero'ed".
2nd pic is with a 33lb weight.
3rd pic is with door.
Last edited by bigdv519; May 2, 2011 at 07:49 PM. Reason: spelling
Assuming you have a cage to make up for taking the brace out?
That seems damn light, I know how heavy these doors are to carry. Be interested in knowing the exact weight... hmm I have a vert door sitting around somewhere
That seems damn light, I know how heavy these doors are to carry. Be interested in knowing the exact weight... hmm I have a vert door sitting around somewhere
Thread Starter
Joined: Mar 2004
Posts: 1,315
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From: Houston
I dont know why, but I didnt weigh the doors in stock form.
Disclaimer: This isnt a show car. The car is primered. Yes there are plans to have a roll cage with drivers-side side-impact bar. Goals are to go fast, looking good comes second.
The work started out with an angle grinder and that seemed like overkill. I switched over to some handheld sheet metal snips. They worked great for the long straight cuts but were exponentially more difficult the tighter the curver became. The side-impact brace was first sliced vertically, then again a few inches away to create some wiggle room. Then the welds were drilled out. Theres some other thick metal bracing near the hinges and that was also removed. Also the guides for the window were also taken out.
I left some material for the stock inside door handle to be attached in the stock location.
The doors now are a little flemsy, but only on the hinge side. I figured I could remove more material here since the hinges would hold the door in place. On the handle side, I left more material and its still fairly strong.
In the first pic, just the webbing was cut out. Also the glass, window motor, and wiring harness. This opening was expanded out.
The second pic is the "final product", painted with some regular black spray can paint. The cutout area between the mounting holes for the hinges is the flemsy area. I dont think it will move too much once its bolted in place on the frame of the car.
Disclaimer: This isnt a show car. The car is primered. Yes there are plans to have a roll cage with drivers-side side-impact bar. Goals are to go fast, looking good comes second.
The work started out with an angle grinder and that seemed like overkill. I switched over to some handheld sheet metal snips. They worked great for the long straight cuts but were exponentially more difficult the tighter the curver became. The side-impact brace was first sliced vertically, then again a few inches away to create some wiggle room. Then the welds were drilled out. Theres some other thick metal bracing near the hinges and that was also removed. Also the guides for the window were also taken out.
I left some material for the stock inside door handle to be attached in the stock location.
The doors now are a little flemsy, but only on the hinge side. I figured I could remove more material here since the hinges would hold the door in place. On the handle side, I left more material and its still fairly strong.
In the first pic, just the webbing was cut out. Also the glass, window motor, and wiring harness. This opening was expanded out.
The second pic is the "final product", painted with some regular black spray can paint. The cutout area between the mounting holes for the hinges is the flemsy area. I dont think it will move too much once its bolted in place on the frame of the car.
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100,000rpm redline
Joined: Mar 2009
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From: whore house aka your mom's house
you could also get rid of the side mirrors and foam the inside of the door. It will not add for protection but at least stiffen it up. I think i'm talking about sea foam or something or "hard stuff"
like this? http://compare.ebay.com/like/3902000...=263602_309572
i use this **** to reinforce my bodykits. **** is awesome
i use this **** to reinforce my bodykits. **** is awesome
Thread Starter
Joined: Mar 2004
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From: Houston
Sorry for not going into further detail. One of my other goals is to have the car look fairly stock from the outside. When I go to the Texas Mile, I might want to remove the mirrors. Thanks for the tip though.
Thread Starter
Joined: Mar 2004
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From: Houston
get an air nibbler and a die grinder to smooth out the sharp edges, that will allow you to take off more material easier and quicker. gut out the mirrors and epoxy the glass in place where you need them aimed. i would also get some compressed cardboard(i forget what is called) and make some makeshift door panels, i made some for the repu and they really don't weigh much and i would much rather have them on there to keep myself from getting sliced up on the raw metal in case of a real accident which likely will happen.
Joined: Mar 2001
Posts: 31,837
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From: https://www2.mazda.com/en/100th/
our last tech inspection on the race car, the inspector had us either roll the edge of the inner door, or put some kind of protector on it, so its not sharp.
Thread Starter
Joined: Mar 2004
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From: Houston
Karack - Awesome advice. I didnt plan on going into the mirrors, but I will now.
j9fd3s - Wow, I hope they let me pass with mine. I removed 98% of the burrs with a sanding wheel on a angle grinder. Maybe I'll add a split silicone hose to that edge. It would make it look really nice and take away any sharp edges.
Rob XX 7 - I remember seeing a show, I think myth busters, about how driving with the windows down decreased the fuel economy with additional drag and turbulence (sp).
j9fd3s - Wow, I hope they let me pass with mine. I removed 98% of the burrs with a sanding wheel on a angle grinder. Maybe I'll add a split silicone hose to that edge. It would make it look really nice and take away any sharp edges.
Rob XX 7 - I remember seeing a show, I think myth busters, about how driving with the windows down decreased the fuel economy with additional drag and turbulence (sp).
trying to build a racecar
Joined: Sep 2002
Posts: 580
Likes: 1
From: Austin, Tx.
Here's what I did for my door actuator.
Cheap, simple, easy to make.
-edit- I'm a noob and can't figure out how to re-attach an image that I already posted to the forum
http://www.rx7club.com/forum/attachm...chmentid=75179
Cheap, simple, easy to make.
-edit- I'm a noob and can't figure out how to re-attach an image that I already posted to the forum
http://www.rx7club.com/forum/attachm...chmentid=75179
Thread Starter
Joined: Mar 2004
Posts: 1,315
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From: Houston
Thread Starter
Joined: Mar 2004
Posts: 1,315
Likes: 0
From: Houston
UPDATE:
Well guys I finally got around to getting a weight of a stock similiar door. This would be a leather door panel, electric windows and mirrors, coupe door. Completely stock.
The door weighed in at a whooping 76lbs. So my doors at 27lbs achieve a total weight loss of
<drumroll>
98 LBS!!!
If we were to calculate lbs per horsepower, my car at last official (its much lower now) weight (2525lbs) and dyno (353rwhp) would achieve a ratio of 7.15 lbs per horsepower. At the new weight (2525 - 98 = 2427), and same hp, the car yeilds a 6.875 lbs per horsepower ratio.
Rough math equivilent of a 14.25rwhp gain (2525lbs / 367.25hp = 6.875 lbs/hp).
I'd say it was a lot of effort to "gut" the doors. On a difficulty scale of 1 to 10, maybe a 3 or 4 for me. I also spent about 8 total hours working on them. If I had to do it again, I could easily cut that time in half.
Now for me to lose some weight!!! LOL.
Well guys I finally got around to getting a weight of a stock similiar door. This would be a leather door panel, electric windows and mirrors, coupe door. Completely stock.
The door weighed in at a whooping 76lbs. So my doors at 27lbs achieve a total weight loss of
<drumroll>
98 LBS!!!
If we were to calculate lbs per horsepower, my car at last official (its much lower now) weight (2525lbs) and dyno (353rwhp) would achieve a ratio of 7.15 lbs per horsepower. At the new weight (2525 - 98 = 2427), and same hp, the car yeilds a 6.875 lbs per horsepower ratio.
Rough math equivilent of a 14.25rwhp gain (2525lbs / 367.25hp = 6.875 lbs/hp).
I'd say it was a lot of effort to "gut" the doors. On a difficulty scale of 1 to 10, maybe a 3 or 4 for me. I also spent about 8 total hours working on them. If I had to do it again, I could easily cut that time in half.
Now for me to lose some weight!!! LOL.