The weight saving thread

[richie]

Richie, I do not know what or how to "beat you" right now. Gasoline refill door in CF?
Replace the roof?
Make a full CF VW tub beetle? That would be cool! 
I guess I should start by installing my doors and the missing rear bumper too.

Anyway, these are two pictures from my workplace. Maybe a CF wheel for our beetles? Naw, price would be silly just to do the tools needed.
I am practical guy and my only formal title is Composite Engineer (diploma from the early 80´s) but I am neither very skilled or have any practice on the topic doing the CF parts myself. So buying the parts is expensive.
But dreaming is fun!

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Stuff like carbon wheels is way out of my skill level as well, I do have some winter plans which will really push me though, if i can make it work will be quite out there

[richie]

1st "light street" version out mould today, this has some extra carbon where rear tail lights attach, and also mounting edge and around front bottom lip for running board to bolt through but realistically its about as light as you would want to go.  
1st pic is fresh out of mould and second pic is weight after main trimming done but not mounting holes drilled or bumper slot cut out

[richie]

I have also been working on fronts, with the added aero pushing down on the front end the top of the front tyre was getting to close to the wing, so I used the bulged fronts i made a few years ago as a pattern, then added more height and area to the bulges for extra clearance, then painted them and created the moulds, unfortunately one didn't work as i had a big chemical reaction between wing surface and mould gelcoat but I finished the one that did and created this from it  Now to fix the other wing and re paint etc to make other side  

[spanners]

This is the picture Neil mentioned that provoked me to make the carbon bonnet, you can see the fiberglass version collapsing on the top area and this is only at 130mph so going 170 who know how bad it is

thats intreaging as that area would be at lower pressure than the fronta areal, my guess is you have a pressure differential with lower pressure under the hood, i had plastic side windows ,badly fitted, and they came out at the top at around eighty five mph, at the same time as the semaphores lifted out with the rain gutter deflection, is it open to ground under the hood ?
 

[richie]

is it open to ground under the hood ?
 

No its filled in best i can do[flat undertray from back of splitter edge to front of floor as wide as possible so doesn't interfere with suspension]

[ibg]

I am upgrading my Karmann Ghia road/track car. I'm trying to get the most weight out of the rotating assemblies, then generally get the car lighter even though I've added a cage and a berg 5. At the moment I'm mostly working on brakes and hubs, I have changing to ventilated disks at the front and I'd like to get them as light as the stock disks.
The disk needs mass to absorb heat, everything else get lighter. So 944 hubs, Ti studs, etc. First up I made these caps, I beat the tops out of sheet aluminium and cut off some 2 1/4 tube, braised them together, sanded and polished them in the lathe ('cos its a hobby  ). The hole in the top needs finishing square for the speedo cable.
I'll add some other pictures as time permits.
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[ibg]

The rear gearbox cradle weighs a bit, and I had seen these alloy ones on a German site but they were no longer made, eventually one came up on the samba. Once bought, I drilled a few more holes, drilled early bolts, they are lighter than the late bolts (19g) and used early washers, lighter as well (3g) than late washers. I know its a bit obsessive  but i'm following in the footsteps of many on this thread.
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[spanners]

is it open to ground under the hood ?
 

No its filled in best i can do[flat undertray from back of splitter edge to front of floor as wide as possible so doesn't interfere with suspension]

Ah, ok Richie , ive just seen your pic and that tells me a lot, the air dam and splitter are working very well, you have good negative pressure under there and thats whats deforming the hood, i use a similar setup on my circuit car but have to run at four inches to the deck at rest, the only thing so far ive gained with no serious on track handling testing yet is lower oil and coolant temperatures with lower underside pressure pulling more air through the systems, the next step is a decent rear diffusor to clean up the exit air flow which with our flat fours is something of a corked bottleneck, ive managed to get the cork out somewhat, its a big task but the rewards are there. love the carbon work ur doing, i made a glass roof for my autocross car years back before they were banned. a nice saving in carbon..

[Garrick Clark]

Richie, Dare I ask how much 2 fronts and 2 rears would cost.

[richie]

Richie, Dare I ask how much 2 fronts and 2 rears would cost.

Rears are £450 each, haven't priced fronts yet as need to make headlight buckets really so can be used on street properly

cheers Richie

[ALB]

The rear gearbox cradle weighs a bit, and I had seen these alloy ones on a German site but they were no longer made, eventually one came up on the samba. Once bought, I drilled a few more holes, drilled early bolts, they are lighter than the late bolts (19g) and used early washers, lighter as well (3g) than late washers. I know its a bit obsessive  but i'm following in the footsteps of many on this thread.
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How thick is the material on the aluminum cradle?

[ibg]

Alb, I had chance to measure it today, all parts of the cradle are 5mm aluminium.
 

[ibg]

I've been working on my front spindles and brakes. My goal was to have something as light or lighter than the Type 1 disks (278mm), but vented and more thermal mass, and Porsche bolt pattern and still fit in a 15" wheel. I used alloy 944 hubs and vented disks, 282mm diameter, and wilwood Dynapro 4 piston calipers. Lanner in Canada made the brackets to fit the radial mount calipers to the VW (or Mendeola spindles). I cut some mass out of the back of the disk and used Ti fasteners. I ended up saving 1.332 kg
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[brewsy]

I've been working on my front spindles and brakes. My goal was to have something as light or lighter than the Type 1 disks (278mm), but vented and more thermal mass, and Porsche bolt pattern and still fit in a 15" wheel. I used alloy 944 hubs and vented disks, 282mm diameter, and wilwood Dynapro 4 piston calipers. Lanner in Canada made the brackets to fit the radial mount calipers to the VW (or Mendeola spindles). I cut some mass out of the back of the disk and used Ti fasteners. I ended up saving 1.332 kg

NICE.
Are you going to run ABS or is that just the way the 'vents' appear on the back side of the disc?

Marc

[PPRMicke]

I get confused that everyone spends a lot of time trying to get the weight down on the front of the car
It gets even easier and the balance of the car gets worse
On a fast drag racing car, you put all the effort into finding the weight at the front (in a prefect world it is 50-50% or 55-45%)
The same with track racing more weight forward, works much better and the balance gets better and the car goes faster
If the car has 80% rear weight then it is 20% front as standard
Then light 10% until Is it good
to reduce weight on rims and tires is good
But a sheet metal rim at the back and a light alloy at the front
If you talk about what the center line of weight distribution is, you work with the chassis of a fast racing car
Maybe you should think twice more
/// M

[richie]

I get confused that everyone spends a lot of time trying to get the weight down on the front of the car
It gets even easier and the balance of the car gets worse
On a fast drag racing car, you put all the effort into finding the weight at the front (in a prefect world it is 50-50% or 55-45%)
The same with track racing more weight forward, works much better and the balance gets better and the car goes faster
If the car has 80% rear weight then it is 20% front as standard
Then light 10% until Is it good
to reduce weight on rims and tires is good
But a sheet metal rim at the back and a light alloy at the front
If you talk about what the center line of weight distribution is, you work with the chassis of a fast racing car
Maybe you should think twice more
/// M

Micke, I mostly agree   but if you lose 10kgs from 0.5m from front of car, then add 5kgs to actual front of car it is still lighter, but front/rear weight balance is better   I think we agree it is how you place the weight that matters I have 35kg piece of lead that is 3 1/2 inches from ground[car has to have 3inches clearance for track rules] and maybe 1inch from front of car, so basically as far forward as possible.
Everything that is behind that place on car i look at to try lose weight   

Happy new year to you   cheers Richie

[ibg]

Marc, no ABS for me, its just how much of the vents was left after I cut away the back of the disk that wasn't going to touch the pad.
Micke, I agree about the overall weight distribution and a lot of work is going into lightening the rear of the car to improve overall balance and moving weight inboard. As a road race car I would like it closer to 50/50 then I still consider whether to have the weight close to the centre line for better turning response or forward of the front axle as Richie suggests, for best weight distribution. With that in mind I've got a fibreglass rear bumper and and steel front bumper.
I put a lot of work into the rotating assemblies because the lighter they are the easier it is to accelerate them and get them to change direction and the suspension is much more responsive with less unsprung weight. I agree a light wheel and tire is more important as they are further from the centre line of the axle (spinning forces) but less weight in the hubs/brakes helps the wheels stay in contact with the road better

[PPRMicke]

Marc, no ABS for me, its just how much of the vents was left after I cut away the back of the disk that wasn't going to touch the pad.
Micke, I agree about the overall weight distribution and a lot of work is going into lightening the rear of the car to improve overall balance and moving weight inboard. As a road race car I would like it closer to 50/50 then I still consider whether to have the close to the centre line for better turning response or forward of the from axle as Richie suggests, for best weight distribution. With that in mind I've got a fibreglass rear bumper and and steel front bumper.
I put a lot of work into the rotating assemblies because the lighter they are the easier it is to accelerate them and get them to change direction and the suspension is much more responsive with less unsprung weight. I agree a light wheel and tire is more important as they are further from the centre line of the axle (spinning forces) but less weight in the hubs/brakes helps the wheels stay in contact with the road better

Glad you think that way
There are many pitfalls when building a car for track racing / street
A tip that can be good to know
As the lateral force on the wheel suspension That it wants to flex a lot
Like the spider pin that often wants to bend by the lateral force
Then the whole spider wants to flex if you do not choose the right material
How to notice this is that the brake pads want to leave the disc after cornering   And you get a long brake pedal
/// M

[karmi]

Plastic screws for fenders   [ Attachment: You are not allowed to view attachments ] [ Attachment: You are not allowed to view attachments ]

[ibg]

14 g saving is not a lot, but..... there are a lot of these bolts. And it's cheap and easy, and they don't rust, win, win, win.
Good work 

[brewsy]

Plastic screws for fenders   [ Attachment: You are not allowed to view attachments ] [ Attachment: You are not allowed to view attachments ]

Did you buy or print them yourself??

Cheers

[karmi]

Bought from e-bay. Are from Cina, but are ok. 36 screws for the fenders are 36x14g = 504g. No rust and if you have a crash, the side wall won't bend because it will break off.  

[Eddie DVK]

Bought from e-bay. Are from Cina, but are ok. 36 screws for the fenders are 36x14g = 504g. No rust and if you have a crash, the side wall won't bend because it will break off.  

  nice.

You maybe have a link?

[karmi]

https://www.ebay.de/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313&_nkw=Kunststoffschraube+Sechskantschraube+Schwarz+Nylon+Bolzen+DIN+933+M8+M10+M12&_sacat=0

[Eddie DVK]

https://www.ebay.de/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313&_nkw=Kunststoffschraube+Sechskantschraube+Schwarz+Nylon+Bolzen+DIN+933+M8+M10+M12&_sacat=0

Thanks

[Bruce]

Wow, they're cheap too.  A box of 50 delivered for around $9USD.

A couple of years ago, I looked at the fender bolts and bought Al ones (3.6g each). They were quite a bit more $ than the nylon ones.

[richie]

Wow, they're cheap too.  A box of 50 delivered for around $9USD.

A couple of years ago, I looked at the fender bolts and bought Al ones (3.6g each). They were quite a bit more $ than the nylon ones.

I have been getting them from mcmastercarr for a few years now, anything non structural gets them

[ibg]

I remember discussion once about if you could get a Berg5 down to the weight of a 4 speed. Anyway when 'Dangerous' Dave Butler built my gear box I asked him to see what weight he could get out of it. My old box was fairly basic with a super diff, where the new one is all Weddle, plus a Quaife which is heavy. Any way Dave spent a day or more drilling and at the lathe.
first the Quaife

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a fair bit of gear drilling

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[ibg]

modify the ring gear

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The mainshaft also got a thrust bearing (no weight saving)

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[ibg]

The end result......  the 5 speed was 5.7 kg heavier than the 4 speed, but I think it was a great result considering the amount of new metal that goes into a 5 speed, not to mention the Quaife.

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I finished up rifle drilling the clutch shaft and a few holes in the arm.

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I hope to fit it in the next few weeks.