Notices
944 Turbo and Turbo-S Forum 1982-1991
Sponsored by:
Sponsored by: Clore Automotive

Weight reduction ideas

Thread Tools
 
Search this Thread
 
Old 08-19-2017, 09:44 PM
  #16  
Cloud9...68
Burning Brakes
Thread Starter
 
Cloud9...68's Avatar
 
Join Date: Mar 2011
Location: Austin, TX
Posts: 1,219
Likes: 0
Received 19 Likes on 15 Posts
Default

Hmmm... Not sure why a 944 hood would weigh more than a 968's. I weighed mine, and it was nowhere near 40 lbs. Yes, it's very awkward, making it seem like it weighs a ton, but I seem to remember it being in the 20's, low 30's tops. And I was disappointed at how heavy my fiberglass hood is - somewhere in the high teens, as I recall. So, I think I only saved about 10-15 lbs with the fiberglass hood, but it was a long time ago, so my memory is fuzzy. A carbon fiber skin held down by hood pins at the corners would be the ultimate, but again, prohibitively expensive, since a 968 CF hood would be a custom made affair.
Old 08-19-2017, 10:06 PM
  #17  
951and944S
Race Car
 
951and944S's Avatar
 
Join Date: Dec 2001
Location: New Orleans/Baton Rouge
Posts: 3,930
Received 65 Likes on 56 Posts
Default

Originally Posted by PorscheFanatic202
Just got a full door... they are stupid heavy. I was surprised. I'll weigh mine today for a reference.
LOL, yes they are. I have moved an accumulated parts stash a few times over the past 10 years. Doors, taken from donor cars in full are close to the last things I'll grab.

I have a car with fiberglass fenders and hood.

Doors are so light once gutted properly, it's not even worth trade off for fiberglass.

More weight than the difference can be taken from elsewhere for free.

The factory rear 1/4 windows in glass weigh next to nothing...., not worth it either IMO.

T
Old 08-19-2017, 10:28 PM
  #18  
951and944S
Race Car
 
951and944S's Avatar
 
Join Date: Dec 2001
Location: New Orleans/Baton Rouge
Posts: 3,930
Received 65 Likes on 56 Posts
Default

Originally Posted by Cloud9...68
Nicely thought out and well put. Yes, safety always has to come first. Also, it's important to keep things in perspective. I just use the car for sessions at the local driving academy. I look at it as a training tool for my ultimate goal, which is to participate in an arrive-and-driver series (when my kids are out of college) like the Simraceway series at Sonoma International Raceway. I just want to strike a balance between a car that is capable, responsive, and can pass other cars at least as often as it gets passed (there's a lot of high dollar hardware at Driveway Austin), without costing a fortune to run. At this point, I'm just looking for any items that I may have forgotten about. The lexan rear hatch and a lighter passenger seat may be the next, and possibly the last, things I do in the weight reduction department. Unless my friend with the trick Miata adds a turbo - then it's game on
I have this seat listed for sale at Pelican - OMP Pista, 2009 manufacture, never mounted in a car -

SP2 car at right in pic is 2400#



T
Old 08-19-2017, 10:59 PM
  #19  
Humboldtgrin
Drifting
 
Humboldtgrin's Avatar
 
Join Date: Jun 2014
Location: NORTHERN CALIFORNIA
Posts: 2,268
Received 18 Likes on 17 Posts
Default

Originally Posted by Cloud9...68
Hmmm... Not sure why a 944 hood would weigh more than a 968's. I weighed mine, and it was nowhere near 40 lbs. Yes, it's very awkward, making it seem like it weighs a ton, but I seem to remember it being in the 20's, low 30's tops. And I was disappointed at how heavy my fiberglass hood is - somewhere in the high teens, as I recall. So, I think I only saved about 10-15 lbs with the fiberglass hood, but it was a long time ago, so my memory is fuzzy. A carbon fiber skin held down by hood pins at the corners would be the ultimate, but again, prohibitively expensive, since a 968 CF hood would be a custom made affair.
Because a 944 hood is physically bigger than a 968 hood.
Old 08-20-2017, 08:16 PM
  #20  
333pg333
Rennlist Member
 
333pg333's Avatar
 
Join Date: Feb 2006
Location: Australia
Posts: 18,926
Received 98 Likes on 81 Posts
Default

Unless this is a pure track car with a proper cage I wouldn't risk going to non OEM doors. I had experience with a pretty heavy impact crash on a track with the stock doors and they provided a lot of protection. With f/g doors you'd be at risk of serious injury if the worst happened.
Old 07-13-2018, 05:39 PM
  #21  
sm
Drifting
 
sm's Avatar
 
Join Date: Oct 2001
Location: Northeast
Posts: 2,562
Received 72 Likes on 60 Posts
Default

Originally Posted by 333pg333
Unless this is a pure track car with a proper cage I wouldn't risk going to non OEM doors. I had experience with a pretty heavy impact crash on a track with the stock doors and they provided a lot of protection. With f/g doors you'd be at risk of serious injury if the worst happened.
For a Street car without a cage, what do folks think about using fiberglass or carbon fiber front fenders and rear quarter panels? Do they significantly reduce crash protector the passengers? This is WITH the full factory steel doors. Thanks.
Old 07-13-2018, 06:03 PM
  #22  
MAGK944
Nordschleife Master
 
MAGK944's Avatar
 
Join Date: Jun 2007
Location: Palm Beach, Florida
Posts: 6,769
Received 298 Likes on 231 Posts
Default

Originally Posted by sm


For a Street car without a cage, what do folks think about using fiberglass or carbon fiber front fenders and rear quarter panels? Do they significantly reduce crash protector the passengers? This is WITH the full factory steel doors. Thanks.
Anything that bolts on forward of the firewall isn’t part of the structural unibody, so you’re good with fg fenders, hood, bumper cover, header panel and light covers. You do need a cage if you cutout and replace the rear quarter panels with fg, the steel there provides a fair bit of strength to the body and would flex without a cage.
Old 07-14-2018, 12:35 AM
  #23  
Cloud9...68
Burning Brakes
Thread Starter
 
Cloud9...68's Avatar
 
Join Date: Mar 2011
Location: Austin, TX
Posts: 1,219
Likes: 0
Received 19 Likes on 15 Posts
Default

Originally Posted by 951and944S

Doors are so light once gutted properly, it's not even worth trade off for fiberglass.

T
Do you (or anyone else who has done this) have any pictures of how you gutted your doors? I know that sounds like a dumb question, but I still drive my car to and from the track, and on occasional errands when none of the other cars in the family are available, so I would still need some windows that at least somewhat functional, however manually. Plexiglass would be fine, even preferred due to their light weight. So, my question is, how do you replace the stock glass windows, motors, regulators, etc., with some sort of manual set-up that looks at least somewhat convincing to prying eyes in a grocery store parking lot? And what is the heaviest part of the doors that get removed when you gut them, or is it the combination of the above mentioned parts that add up to a significant amount of weight? Thanks.
Old 07-14-2018, 01:26 AM
  #24  
951and944S
Race Car
 
951and944S's Avatar
 
Join Date: Dec 2001
Location: New Orleans/Baton Rouge
Posts: 3,930
Received 65 Likes on 56 Posts
Default

Yup, will pop you up a few pics this weekend. Can weigh a stock door vs one of my gutted doors but it'd be a few days..

The weight difference is drastic.

You would have to select a Lexan/plexi thickness and then make channels for it to slide up/down in.

T
Old 07-14-2018, 05:35 AM
  #25  
PF
Rennlist Member
 
PF's Avatar
 
Join Date: Jan 2010
Location: Sweden
Posts: 1,263
Received 373 Likes on 183 Posts
Default Light Doors full stock function

Hi.

With my car (968 CS) I wanted fully stock function and look but as light as possible.
My doors have gf outer skin with weight savings made to steel inside and to manual winding mechanism which is very heavy stock. Further I have hardened scratch resistant lexan windows from plastics for performance in the UK. Overall weight is about half of stock door but still look fully
stock and have winding windows. My car also have full aluminium cage.
Old 07-14-2018, 09:06 AM
  #26  
MAGK944
Nordschleife Master
 
MAGK944's Avatar
 
Join Date: Jun 2007
Location: Palm Beach, Florida
Posts: 6,769
Received 298 Likes on 231 Posts
Default

Originally Posted by PF
...My doors have gf outer skin....
Often wondered if skinning the doorswoth fg is worth the effort as the steel is so thin anyway compared to the fg that replaces it. Did you happen to weigh the steel door skin and the fg replacement skin to confirm any weight savings?
Old 07-14-2018, 09:29 AM
  #27  
PF
Rennlist Member
 
PF's Avatar
 
Join Date: Jan 2010
Location: Sweden
Posts: 1,263
Received 373 Likes on 183 Posts
Default

Originally Posted by MAGK944


Often wondered if skinning the doorswoth fg is worth the effort as the steel is so thin anyway compared to the fg that replaces it. Did you happen to weigh the steel door skin and the fg replacement skin to confirm any weight savings?
They were skinned when I bought the car but the guy who makes them here in Sweden showed me both skins and although I didnt weigh them there was a big difference. For safety sake I would rather keep the inside of the door and skin The outside than cut the whole inside out to reduce weight.
The winding mechanism I lightened myself which together with the lexan windows shaved 4,5kg per door. If I remember correctly the stock clubsport door weighed 31kg versus my doors at 13kg. Look and function is identical. Ofcoarse safety is not god this way byt together with my cage it is ok
Old 07-14-2018, 12:03 PM
  #28  
951and944S
Race Car
 
951and944S's Avatar
 
Join Date: Dec 2001
Location: New Orleans/Baton Rouge
Posts: 3,930
Received 65 Likes on 56 Posts
Default

Originally Posted by MAGK944


Often wondered if skinning the doorswoth fg is worth the effort as the steel is so thin anyway compared to the fg that replaces it. Did you happen to weigh the steel door skin and the fg replacement skin to confirm any weight savings?


IMO, no, not worth it. The metal of the skin is about .040", which is around 1.5-1.75 lbs per square foot.
If you guesstimate the door exterior to be 1 sq yard, or 3 feet square, 4.5 lbs of sheet metal thereabouts.

Same area of fiberglass cloth, let's say 6oz cloth, which is just that 6oz per sq yard...., three layers of just cloth is going to be 18oz cloth.
An accepted formula, cloth saturated, weight of resin is 2 x weight of cloth, so for that area, 36oz resin minimum.
So, 54 oz of material, not counting corner reinforcement, etc, is 3.375 lbs.

1-1.2 lbs savings at a location of the car where weight savings has the smallest advantage.

Now when you get rid of the entire door for a fiberglass or carbon replacement, this is when it pays off because many portions of the door are double and some even triple thickness sheet.

T
Old 07-14-2018, 12:22 PM
  #29  
PF
Rennlist Member
 
PF's Avatar
 
Join Date: Jan 2010
Location: Sweden
Posts: 1,263
Received 373 Likes on 183 Posts
Default

Originally Posted by 951and944S
IMO, no, not worth it. The metal of the skin is about .040", which is around 1.5-1.75 lbs per square foot.
If you guesstimate the door exterior to be 1 sq yard, or 3 feet square, 4.5 lbs of sheet metal thereabouts.

Same area of fiberglass cloth, let's say 6oz cloth, which is just that 6oz per sq yard...., three layers of just cloth is going to be 18oz cloth.
An accepted formula, cloth saturated, weight of resin is 2 x weight of cloth, so for that area, 36oz resin minimum.
So, 54 oz of material, not counting corner reinforcement, etc, is 3.375 lbs.

1-1.2 lbs savings at a location of the car where weight savings has the smallest advantage.

Now when you get rid of the entire door for a fiberglass or carbon replacement, this is when it pays off because many portions of the door are double and some even triple thickness sheet.

T
For a racecar NO. But if you as me and probably some others want to street your car but want as light as possible doors/car still retaining stock function then it is worth it IMO. Not possible with carbon doors or fully gutted insides.
My doors give you the comfortable feeling of a stock door at 13kg a side which to me is ok.
Personally I dont like not being able to wind the windows down.
It is all a matter of personal preference as always.
Old 07-14-2018, 06:22 PM
  #30  
Cloud9...68
Burning Brakes
Thread Starter
 
Cloud9...68's Avatar
 
Join Date: Mar 2011
Location: Austin, TX
Posts: 1,219
Likes: 0
Received 19 Likes on 15 Posts
Default

Originally Posted by 951and944S
Yup, will pop you up a few pics this weekend. Can weigh a stock door vs one of my gutted doors but it'd be a few days..

The weight difference is drastic.

You would have to select a Lexan/plexi thickness and then make channels for it to slide up/down in.

T
Thanks. Why do you have to make new channels for the plexiglass to slide in? Why not use the stock channels that the glass slides in? And what keeps the plexiglass in place? And what about the interior door latch - is there a way to retain that with a gutted door? I guess that isn't essential - I suppose I could reach out and open the door from the outside, but keeping the interior latch would make it more convenient. Sorry for all the dumb questions - as you can tell, I've never done this before, and am debating whether it's a good idea in my case. Again, my car is primarily a track toy, but I drive it to and from the track, which is about 20 miles from my home, and occasionally make stops on the way home, so I'd like to find a balance between weight savings, a stock (from the outside) appearance, and some rudimentary semblance of function. I don't need to retain the ability to crank the windows up and down, but I do need to be able to to leave the windows in place so the car looks secure to the casual observer.


Quick Reply: Weight reduction ideas



All times are GMT -3. The time now is 06:30 AM.