924srr27L Lightweight Doors / Suspension / Bump steer etc..

[wolfie308]

Surprised no one else has suggested this before.....how about drilling the roof full of holes too?.....double benefit.......reduced weight and lower centre of gravity! Optional vinyl wrap to cover for wet weather? [8|]

 

[wolfie308]

In the event of the worst happening, here's a reminder of why I wouldn't want to compromise the integrity of my doors. After a triple impact, I had to kick the driver's door open to get out. If I'd taken a side impact with Holy doors, I'd be writing this from on high.

 

[924Srr27l]

Surprised no one else has suggested this before.....how about drilling the roof full of holes too?.....double benefit.......reduced weight and lower centre of gravity! Optional vinyl wrap to cover for wet weather? [8|]

Sure, 10kg was removed with the Big Sunroof Panel, there's not that much Steel left around the sunroof perimeter,

but if I was to revise this area again I'd chop off the whole roof and fit a Carbon Fibre one.

The rear Torsion Tube was drilled with 90 holes and Vinyl stickered up !

There's holes in all the Discs too...(500 grams lighter than OE each)

Holy Alternator bracket v OE .........

Cam Pulley

Holes in The LSD

R

 

[vitesse]

This is fascinating stuff or dare I say wholesale modification -the one thing we haven't experienced yet is a hologram.However to be fair to Roger,during my life ,most lightening methods have employed perforations,holes,lightweight materials & minimalist construction methods-the world of Colin Chapman et alia.

Most lightweight E-Types I've seen are usually full of holes wherever possible too reduce weight,but I do think great care needs to be taken with door frames which transfer impact loads in crash situations.

 

[924Srr27l]

This is fascinating stuff or dare I say wholesale modification -the one thing we haven't experienced yet is a hologram.However to be fair to Roger,during my life ,most lightening methods have employed perforations,holes,lightweight materials & minimalist construction methods-the world of Colin Chapman et alia.

Most lightweight E-Types I've seen are usually full of holes wherever possible too reduce weight,but I do think great care needs to be taken with door frames which transfer impact loads in crash situations.

Yes our Colin was prone to building Lightweight cars...

(From the Museum Website)

The reasons are [particularly when applied to a motor car]:

[ol][*]Manoeuvrability- improved handling and road holding – less weight to be moved[*]Power to weight ratio advantage[*]Improved acceleration and de-acceleration[*]Fuel and materials efficiency[/ol]Weight reduction forms the most powerful spiral of benefits and can be expressed thus: Reduce weight of chassis permits:

[ol][*]Reduction in engine size and weight[*]Reduce size brks’ and tyres[*]Reduce suspension components improve handling[*]Reduce body weight and volume[*]Leading to greater fuel economy[*]Smaller tank; lower weight[*]Chassis can be redesigned around smaller overall lighter components.[/ol]Lightweight construction is also a function of sprung and unsprung weight distribution and its impact on handling.

R

 

[John Sims]

Try jacking the corner of the car up with the door open and then try to shut the door should give some indication of how much extra rigidity is gained.

I am impressed with your fascination with drilling holes and fully agree with the benefits of adding lightness. I also appreciate that many small savings can translate to something worthwhile. However, when running analysis I am often surprised how little lightness can be gained (or weight lost) in turning something into Swiss Cheese. In many cases it comes down to not being worth the effort and frequently more can be achieved in removing weight from the squidgy rather than the things around it. Have a smaller fuel tank, move the battery, get a smaller battery, remove the wiring loom and put back only what is necessary. All of these wont give a million holes for rust to take hold. Why do you still have the spare wheel well?

 

[John Sims]

As a matter of interest if your holes in the torsion tube were 20mm dia (and assuming a wall thickness of 2mm) each hole will gain 5 grams of lightness.

 

[924Srr27l]

Try jacking the corner of the car up with the door open and then try to shut the door should give some indication of how much extra rigidity is gained.

I am impressed with your fascination with drilling holes and fully agree with the benefits of adding lightness. I also appreciate that many small savings can translate to something worthwhile. However, when running analysis I am often surprised how little lightness can be gained (or weight lost) in turning something into Swiss Cheese. In many cases it comes down to not being worth the effort and frequently more can be achieved in removing weight from the squidgy rather than the things around it. Have a smaller fuel tank, move the battery, get a smaller battery, remove the wiring loom and put back only what is necessary. All of these wont give a million holes for rust to take hold. Why do you still have the spare wheel well?

I'll try the jack up trick, which is best the front or rear jack up point ?

I started with a Simple Seat change from OE to Kevlar buckets which with the Spare wheel removed, the jack / handle and the rear seat back and carpet

came to 60kg. This was the first thing I did and I was surprised that this was noticeable when driving it.

So then I wanted more and took out all the side glass, then the electric motors for wind up's, then the Sunroof panel and elec motor..

Then after a Fibre bonnet and Rear bumper I decided to Import the 2.7 Engine and from here onwards almost every area was looked at and a lot

more items replaced with lighter or many items taken off if they were not required.

So many more things were spotted that I didn't think of , or was aware of when I was restoring or replacing parts, lots of items only saved 500 grams but probably x20.

I was set to go for an Aluminium Fuel tank, but the Pressed Steel OE one is not heavy at all , so I didn't bother.

The battery is in the front scuttle but it's not worth moving it to the back as I replaced the 15kg Bosch unit with the 3kg Lithium.

The Spare wheel Well also could of been cut out and welded up, but I couldn't be bothered to get this done, besides it was built as a Road car and

hence I do have a Skinny 6x16 Boxster Spare and Space Saver Tyre if needed.

There's probably a fair bit more I could reduce if I went down the route of racing it, and took out the Heater, all the carpets, and the Passenger seat etc..

But for now it's staying as a Usable reasonably comfortable Road car with a Full Interior trim, I have also added some deadening in the back and tunnel

as it's boomy @ 3000rpm.

Reductions / Area's

Body 80Kg

Interior 80kg

Engine bay 40KG

Suspension & Brakes 20kg

Exhaust System 16Kg

Misc 14kg

Total 250kg

Start Weight 1260kg

End 1010kg

R

 

[DarrylH]

The amount of weight saving you have done so far does amaze me that you haven't been bothered to remove the wheel well.

I would have personally taken side impact over a spare wheel and well, but that's just my 2 pence. Sounds like an interesting project.

 

[tscaptain]

If it was me 15kg off the driver weight would help too![]

 

[924Srr27l]

If it was me 15kg off the driver weight would help too![]

I've lost 10kg in the last 6 months, now down to 70kg []

R

 

[924Srr27l]

The amount of weight saving you have done so far does amaze me that you haven't been bothered to remove the wheel well.

I would have personally taken side impact over a spare wheel and well, but that's just my 2 pence. Sounds like an interesting project.

As I said I wanted to retain a space for the Spare wheel, and I didn't want it laying on the top..

These Doors will have side impact metal tubes, and they are Steel.

Only I was set on full fibre doors which really would of been paper Mache strong!

R

 

[924Srr27l]

Try jacking the corner of the car up with the door open and then try to shut the door should give some indication of how much extra rigidity is gained.

In regard to chassis / Body Rigidity the centre of the shell and rear section is under tension / compression,

each Metal tube has a left & right hand Rod end either end.

Each tube is screwed tight putting a strain and tension on the adjoining brackets and B & C posts.

The centre tube has a bracket which is bolted to the Captive Nut in the Shell, the front bars locate and bolt where the seatbelt was.



Fitting these Triangulated array of bars stiffened the chassis so much it was very noticeable when driving it.

I can and probably will add some more tubes laterally across the sunroof, and possibly from the seatbelt B pillar to the Floor footwell.

R

 

[PSH]

As a point of interest, the 951's racing in the Porsche cup back in the late 90's got their weight down to 1000kg, one of the biggest savings being the carpet, underlay, dash etc and for the diehard's the complete removal of the underseal which weighs a ton...figuratively speaking that is..

Pete

 

[924Srr27l]

As a point of interest, the 951's racing in the Porsche cup back in the late 90's got their weight down to 1000kg, one of the biggest savings being the carpet, underlay, dash etc and for the diehard's the complete removal of the underseal which weighs a ton...figuratively speaking that is..

Pete

Was this in the UK ?

I think this below is the American series 944Turbo Cup only it quotes 1280kg?

http://944turbo.net/?page_id=88

R

 

[Eldavo]

Btw - It shouldn't surprise me given your laissez faire attitude to safety but a reasonable accident will see you with a broken spine given your harness strap locations.

You'd be better running the straps over the cross bar provided you're sure about its strength and rigidity.

 

[924Srr27l]

The amount of weight saving you have done so far does amaze me that you haven't been bothered to remove the wheel well.

I would have personally taken side impact over a spare wheel and well, but that's just my 2 pence. Sounds like an interesting project.

As I said I wanted to retain a space for the Spare wheel, and I didn't want it laying on the top..

These Doors will have side impact metal tubes, and the frames are Steel.

Only I was set on full fibre doors which really would of been paper Mache strong!

R

 

[PSH]

As a point of interest, the 951's racing in the Porsche cup back in the late 90's got their weight down to 1000kg, one of the biggest savings being the carpet, underlay, dash etc and for the diehard's the complete removal of the underseal which weighs a ton...figuratively speaking that is..

Pete

Was this in the UK ?

I think this below is the American series 944Turbo Cup only it quotes 1280kg?

http://944turbo.net/?page_id=88

R

Hi Roger

Yes it was in the UK, is was the PCGB Porsche Pirelli cup and later the Michelin cup, or was it the other way around? late 90's early 2000's The 'Turbo Cup' series was a different thing altogether, back in the 80's and finished long before the PCGB championships. That was a factory series with all one class, the 944 T, the later PCGB series was multi class finishing with the 996 GT3's ( the 944T could still beat them). As you can see the Turbo cup cars were basically the same weight as the early turbo's even with the magnesium parts fitted, they had better brakes which probably made up the difference in weight, that and the rollcage.. They were race cars but not in the same vein as a true racer that had been stripped of all unneeded weight which is what was done to most of the cars in the PCGB series....Andrew Sweetenham if he pops onto the forum these days could tell you much more as he raced in the series. IIRC you said that Wayne Schofield is a family friend?, if so he'll be able to tell you much more as he was involved in setting up the best 944 turbo driver, 'Chris Heeley's car and many other cars involved in the championship too.

Pete

 

[John Sims]

Btw - It shouldn't surprise me given your laissez faire attitude to safety but a reasonable accident will see you with a broken spine given your harness strap locations.

You'd be better running the straps over the cross bar provided you're sure about its strength and rigidity.

Indeed so. A friend of mine came close to dying in a crash when the seat back crushed allowing the belts to go slack.

An interesting use of tubes. I don't really see the point of the rear one as it is behind any of the suspension mounting points and triangulating to the middle of a tube isn't ideal.

Personally I am pretty much averse to harnesses without a roll hoop as, should the car roll, you can't get out of the way if the roof compresses. A roll hoop is pretty much the minimum Blue Book requirement for any series and deemed adequate in only the most lowly of events.

I think you would be far better stripping out your home made scaffolding and putting in some proper protection that can be suitably triangulated and provide an adequate seat belt mounting.

And, (with regard to removing the heater) very sensibly, most race series for enclosed cars specify a heater or demister of some kind must be provided as not being able to see out of the screen isn't considered terribly safe.

 

[944 man]

They serve no purpose, but Im not wasting the 'breath'.

With regards to weight: if the car hasn't been dipped then no amount of spurious drilling is going to get its weight down.