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240Z Doors - Weight reduction mod's


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Hi there Guys,

 

I attacked the doors off my racecar today. I was wanting to reduce the weight of them as much as possible. And after reading a couple of other threads on here, i got into it.

 

I had already removed the glass and regulator, so now I cut out the whole inner panel, but left the side frame to give the door some stiffness (On another previous racecar - Not a Zed - I only had the outside skin and if wobbled and flexed all over the place at speed - Not ideal)

 

Once the inner panel was gone, i then removed the little stiffning bar that ran the lenght of the door, hard up against the skin. Cant really call it an intrusion bar, as it is pretty light pressed steel.

 

This came out pretty easy really - Undo the two scews at one end, and then drill out the two spot welds at the other end - Too easy.

 

The next task is too cut/punch some holes (using chassis punchs) in the rear end and bottom part of the frame (as per the red circles on the photo) Dont really think i wanna cut holes in the front part, as the hinges attach there, and i should probably leave that a bit stiffer to support the weight of the door, all be it reduced.

 

I simply used a 1mm thick cutting disc on a 115mm angle grinder - They work very well - Like a hot knife thru butter :wink:

 

Just got to clean up the edges now, and eventually after painting i will push on a strip of rubber molding over the edge to tidy it up, and not have a sharp edge.

 

For those wondering how i will open the door from the inside, i will simply attach a pull cord from the lock lever accross to the front end of the door - Just like Ferrari did on the F40 :-) Nice and light.

 

I do have two sets of doors for this car, so i can put the other stock set on if i ever need/want to have wind up windows etc.

 

Edit:

I just weighed the pieces that i cut out/removed from one door - 3.5kg - so that will be 7kg over both doors and by the time i cut the holes - Hopefully we get close to 10kg total weight saving over a pair of already bare stripped doors. - Doesnt sound like a lot, but all these little bits add up. And being lighter improves all areas of performance, acceleration, braking and turn in and handling.

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Now go after the hinges as they weigh quite a bit and should be able to be made considerably lighter with the lighter door weight.

 

Cameron

 

Yes, they are still bolted onto the car, however they do look like they are cast and quite heavy.

 

There was someone on here who had some alloy hinges cnc'd up, they looked sweet, and would be the go - But probably very expensive for the weight saved.

 

I will see what i can do with the stock ones.

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I just gutted my 280 door, and that piece you said was easy to get out of the 240 door was a real pain in the butt to get out. I left the door handle in its place and it still works after cutting all the inside metal away. anyways I'll weight the next door before I cut it all up for a weight difference but I bet it's more like a 30-40 lbs different with a 280 door. The lighter the better.:-)

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Yeah even the 240 doors (which are the lightest of the 3) are still bloody heavy in stock form.

 

People that have never lifted a door that has not been attached to their car will sh!t themselves when they first realise the weight of these things - Crazy!!

 

I could go weigh a totally stock 240 door for a comparison.

 

You guys with the 280z doors will save way more weight than me as the side intrusion bars in them are huge is comparison to the 240 ones - HUGE!

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Ok,

 

I have just weighed a totally stock 240z door (including the door trim panel) at 23.65 kilograms (52.14 lbs)

 

And my stripped and cut out door with the glass frame bolted back on but no glass (but havnt cut the planned holes yet) at 11.05 kg (24.36 lbs)

 

So a total weight saving of 12.6 kg (27.77 lbs) per door, so thats over 25kg (55 lbs) for a pair of doors, and i reckon thats pretty good. - Its like taking one of the doors right off!

 

There appears to be a bit of filler in the bottom of my door too, maybe 10 lbs of it going by the 17 lbs that Jon mentions above :-(

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That's a lot of filler!

 

Here's the thread where Clifton discussed his FG doors. He says "probably under 10":

http://forums.hybridz.org/showthread.php?t=128996&page=3

 

Yeah, looking at the panel on the inside, it doesnt actually appear that there is that much, but, I still have a 7 lbs difference between my door weight and your figures?

 

Who knows....

 

Jon, when you weighed them at 17 lbs, did you have the outer door handle, door lock mechanisium and window frame all fitted?

 

If you didnt, this would explain the 7 odd lb difference.

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Yeah, looking at the panel on the inside, it doesnt actually appear that there is that much, but, I still have a 7 lbs difference between my door weight and your figures?

 

Who knows....

 

Jon, when you weighed them at 17 lbs, did you have the outer door handle, door lock mechanisium and window frame all fitted?

 

If you didnt, this would explain the 7 odd lb difference.

No, mine were totally stripped.

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For the sake of comparison, I weighed the doors from my 260Z while they were off. Complete with glass, regulator and inner door panel they weighed 68 pounds.

 

I just cant bring myself to gut my 260Z doors because they are in perfect condition, and I also like being able to wash the car without washing the interior at the same time.:wink:

 

DSCN0768.jpg

 

I have often pondered finding some early 240Z doors and putting them on my 260Z. Just switching to the early doors would save 40 pounds off the car.

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For those in the lower part of the world, i have been talking with a fibreglass motorsport company in Australia, they make many FG parts for Z's, they are currently working on FG doors.

 

They said they will weight approx 4-5kg each and will only cost approx $330 AU$ each, which IMO is extremerly cheap. (Compared to the Jap made ones - where you need to re-mortgage the house to buy them!)

 

Will be avaliable for sale in approx 3 months. They also said if you wanted any of their parts in CF it will be 3 times the FG price.

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