loosing weight

loosing weight

Author
Discussion

monaco

Original Poster:

219 posts

283 months

Wednesday 11th September 2002
quotequote all
Chaps

Any thoughts on this one then, how much weight do you think could be lost if I was to strip out as much as possible from my old S1, so that it would have a more favourable power/weight ratio ??
I have an old S1 which I haven't bothered selling since getting the chim. and fancy striping it and just using it as a track day car.

I would be willing to remove anything but the dash, as it would be a pain, but things like carpet door panels, fitting race seats to reduce weight etc, would be no prob's.

Any thoughts ??

gadgit

971 posts

268 months

Wednesday 11th September 2002
quotequote all
Trouble with these cars is where on earth can you loose some real wieght. the baulk of the cars weight is in the engine, gearbox, prop, diff, half shaft, very big wishbones, enormous trailing arms, and in the main a strong steel chassis. the rest of the car in general is then of light construction. although suffering from rust most of the steel used is quite thick but not well protected. fibre glass is heavy in the thick area's but unless you are going to cut chunks out of it you can't really touch it.

you could remove the roof completley, but I would think if you were going to track it on quite a few occasions then you ought to fit a roll bar which would add extra weight.

In all honesty the only ways I would see you getting round faster would be for you to improve the performance of the car by a rolling road tune up, and to improve your driving. Most experts would advise that you can save more time by your technique!

It will be interesting to see what other comments you get, now the ball is rolling!

gadgit.

monaco

Original Poster:

219 posts

283 months

Wednesday 11th September 2002
quotequote all
gadit

Totally agree with your comments, just thought I would throw it in for disscusion.

I intent to fit a full cage If I can find someone to make It, which will probably put the weight back in anyway.

But a lighter S should be a better S in my book !!

we'll see.

keithyboy

1,940 posts

271 months

Wednesday 11th September 2002
quotequote all
Go on a diet Monaco!! Just kidding. Reminds me of my biker days when the in-thing was (and still is) to strip your bike down and replace everything in sight with carbon fibre or ally in a bid to lose weight off it - then you'd see some fat b*stard try and hoist himself onto it and pootle off down the road!

shpub

8,507 posts

273 months

Thursday 12th September 2002
quotequote all
Tower View and myself have dramatically reduced the weight on the 520. Dave has made some remarkable lightweight body panels and some 100 kg have gone without resorting to stripping the interior. You need to think sideways though. Mechanically I would leave much alone but you should be able to 100 kgs off by getting a lightweight boot lid, removing the electric window motors and windoes (use plastic), changing the battery for a gel race type (saves 20 KG for a start) and so on.

It will improve the acceleration and handling.

Currently planning for mk2 Wedge diet: it's a high octane low metal diet designed to get another 100 kg off the car!

Steve
www.tvrbooks.co.uk

podie

46,630 posts

276 months

Thursday 12th September 2002
quotequote all
quote:
changing the battery for a gel race type (saves 20 KG for a start)



Jeez, I had no idea a car battery was that heavy...

spnracing

1,554 posts

272 months

Thursday 12th September 2002
quotequote all
The battery in my Golf was 12KG, the one in the Chimaera was 14-15KG. A Varley Red Top is about 4-7KG so the saving is really only about 8-10KG max.

Saving weight is certainly the cheapest way to make a car accelerate faster and brake harder, though people have told me that a saving of 50KG in a hatch like the Golf equates to only 1/2 sec/lap and thats at full tilt.

Weight can be found in;

Carpets
Seats (fit a fibreglass race seat)
Dash
Door trims
Motors (windows, mirrors)
Wiring loom (if there's bits you don't need)
Heater and fan (its full of water and weighs about 10KG in the average car)
Sound deadening
etc etc.

Lance

567 posts

264 months

Thursday 12th September 2002
quotequote all
...and a load in the glass.

Paceracing

729 posts

267 months

Thursday 12th September 2002
quotequote all
quote:

Saving weight is certainly the cheapest way to make a car accelerate faster and brake harder, though people have told me that a saving of 50KG in a hatch like the Golf equates to only 1/2 sec/lap and thats at full tilt.

Weight can be found in;

Carpets
Seats (fit a fibreglass race seat)
Dash
Door trims
Motors (windows, mirrors)
Wiring loom (if there's bits you don't need)
Heater and fan (its full of water and weighs about 10KG in the average car)
Sound deadening
etc etc.


Totally agree.
Weight saving helps all aspects of car handling. It improves braking, suspension handling and acceleration.
You could also remove heater matrix and save a fair amount of weight there as well.
Heving lightweight panels made can be very expensive. I looked into getting a lightweight bonnet made and it would have worked out at £1,500!!! A cheap way to loose weight, is to attack the inside of the car with a hole cutter, you could do the rear panel (which separate the boot from the cockpit), the dashboard, the door frame, cut the inner door skin out completely, polycarb windows, etc......
Any weighty items which need to stay on the car, such as the battery can be reloacted to the space that the old passenger seat used to occupy. This has the added bonus of balancing weight across the car and placing the weight as low as possible inside the car, thereby lowering the C of G.
Get cutting,

Jas.

shpub

8,507 posts

273 months

Thursday 12th September 2002
quotequote all
Before getting your angle grinder out, check the regas if you want to compete in motorsport and most of the mods will put you in the modified I'm a nutter class. Second thing is to consider your own safety as on the S and other TVRs, it is onlt GRP between you and hard things outside. Lightening bodywork without considering additional safety items is pretty fool hardy.

Light weight panels are expensive: I had a carbon fibre wedge bonnet for about 30 minutes before a combination of under bonnet pressure and structural failure caused it to fly off at 70 on the M1 going home. Now have one made from a single layer of Kevlar cloth sprayed with two moelcules of gel coat. The bonnet, front bumber and spolier/splitter came in at under 4 kg for the lot and saved around 45 KG.

The wedge battery did weight in at 25 KG. weighed it on the bathroom scales. The motorised aerial was replaced with a length of stripped coax and saved 4 lb....

Steve

DaveS3c

2 posts

260 months

Tuesday 17th September 2002
quotequote all
Forget the weight savings, go on a trackday and get an instructor to sit in with you - it'll improve your technique no end!

At the beginning of the day I was being overtaken by everything, at the end I was worrying griffs.

mark b

1,621 posts

266 months

Tuesday 17th September 2002
quotequote all
Another good weight saving would be in the wheels. Assuming you still have the original alloys, a decent set of steel rims could be a weight saving. It will reduce unsprung weight to, improving wheel control and therefore handling. Only problem may come in getting wheels with the right offsets.

If you're going for a track day car, tyres, suspension and brakes are the best way to improve handling dynamics. Make sure the suspension is set properly too, although .5 degree toe in wouldn't be a bad way forward either.

If you're going to take lots of weight out, make sure the balance is still there. The S has a heavy engine, so balance will be key.

Podie

46,630 posts

276 months

Tuesday 17th September 2002
quotequote all
Alloys can always be machined to a more appropriate offset... so there's one solution.

Another idea is to go up a size in alloys, but reduce the tyre profile - reducing sidewall flex, but maintaining (roughly) the same rolling radius (give or take 1-2% maybe).

As for weight distribution on the S... I thought it was something like 51/49...?


edit - weight distribution... www.realdriver.com/road_tests/tvr_s3c/tvr_s3c.php

>> Edited by Podie on Tuesday 17th September 13:03

Paceracing

729 posts

267 months

Tuesday 17th September 2002
quotequote all
I'm not convinced that changing the alloys for steel will make much difference. To find alloys with the correct offset and PCD would be a bit of a challenge for a start. I agree that on something like a single seater it would make a significant difference, but the cost versus the gain for an old TVR would be pretty much negligeable IMHO. A car which was originally designed as a road car will have many other areas which will benefit from a tweak here and there.

Regarding weight distribution, the car is reasonably well balanced as it is at nearly 50/50 F/R split. The rear axle could benefit from better balancing as this is around 40Kgs out on avarage, left to right. The key to weight distribution is to put the weight as low in the car as possible, and to put the weight where you want it, hence make the car as light as possible, then put weight back in.

Jas.

>> Edited by Paceracing on Tuesday 17th September 20:59

mark b

1,621 posts

266 months

Wednesday 18th September 2002
quotequote all
Looks like my comments stirred up a few good replies. When discussions arise about the weight saving of different batteries, I thought we were getting into serious weight savings, of which I would think steel rims would save probably 20kg on the car.

Re the fore aft balance of the car, most of the comments seemed to revolve around taking weight out of the cockpit/boot area, which could end up in a front heavy car, resulting in an understeering car.

I agree with paceracing, take weight out of the car and then add it back to balance the car.

Either way, a stripped out TVR S would make a great track car.

Looking in to getting one myself now, and this forum seems a great way to find out useful info.

monaco

Original Poster:

219 posts

283 months

Wednesday 18th September 2002
quotequote all
I'm glad that this has become an interesting thread. The stripping will start shortly

Does anyone know of a cheap source for light, cheap, waterproof racing seats ?? and good harness's ?

I still haven't found a full cage yet either

Thanks for the advice so far.

Paceracing

729 posts

267 months

Wednesday 18th September 2002
quotequote all
Waterproof seats? Try Demon Tweeks for a moulded fibreglass one.
Harness? Luke seem to be the cheapest with FIA certification. Go for 3" lap and shoulder straps and 2" crotch straps.

Jas.

rrouse

2,892 posts

269 months

Thursday 19th September 2002
quotequote all
quote:

Assuming you still have the original alloys, a decent set of steel rims could be a weight saving. It will reduce unsprung weight to, improving wheel control and therefore handling. Only problem may come in getting wheels with the right offsets.


Now I'm confused! I always understood that alloy rims would be lighter than steel rims, thereby providing better handling by reducing the unsprung weight. Additionally, the better heat conductivity of the aluminium should provide better braking performance. Oh, and they tend to look nicer too!

Have I been labouring under a misconception all these years?

Paceracing

729 posts

267 months

Thursday 19th September 2002
quotequote all
quote:

Now I'm confused! I always understood that alloy rims would be lighter than steel rims, thereby providing better handling by reducing the unsprung weight. Additionally, the better heat conductivity of the aluminium should provide better braking performance. Oh, and they tend to look nicer too!

Have I been labouring under a misconception all these years?


You are quite correct. Alloys are better heat conductors and on a size for size basis are usually lighter than pressed steel rims.
Personally I would never use steel rims on the track. It is only my opinion though!!!
From a weight point of view, with the 'S' series cars, I personally think that shedding sprung weight as opposed to unsprung weight will not only be cheaper, but will be far less complicated. Having said that, a decent set of lightweight brake calipers would help a lot, and reduce unsprung weight to boot!!!
When changing wheels, some major points to consider are;
PCD, (Stud pattern to you and I).
Offset, (Determined by king pin inclination, by drawing an imaginary line through the top and bottom ball joints and the centre of the tyre contact patch for optimum handling and steering weight).
Internal Diameter; (Determined by maximum diameter of brake disk and caliper combined).
Rolling Radius; (Will affect gearing in terms of acceleration and top speed).
Wheel Width; (Will have an affect on the available space inside the wheel arch during full suspension compression).
Wheel Design; (Will undoubtedly have an affect on brake cooling).
Wheel Weight; (Will have an affect on handling due to unsprung weight).
If you can solve these issues with different wheels, then my advice would be to change them!

Jas.

John Mac

386 posts

264 months

Thursday 19th September 2002
quotequote all
For info.on Roll Cages look up - www.safetydevices.co.uk. they are based in Cambridge.
If you have thoughts on perhaps your local garage "welding one up" don't overlook that they (the roll cage) usually have to comply with regs. ie. the Blue Book. A proper roll cage is designed for the specific car and takes into account fixing points and loading points, if non exist or are not suitable they have to be built in which adds yet more weight. A roll cage not thought out can be very dangerous. I thought about fitting just a simple Roll BAR for my Dellow and the technicalities needed for it squashed the idea.
Best of luck