Why slimming world is a waste of time

[speedy_g]

Walking around tesco today I couldn't help but notice the post-christmas diet trend, which got me thinking about the weight of my 2

Couple of years ago when I was looking at buying a new car, I was looking at the performance and the weight of various jap cars. Couldn't understand what toyota put in the 2 to make it way more than a 4 door impreza?

Doing a bit of research today, i've done these calculations which I would appreciate some response to

Starting with the assumption that my rev 2 gts weighs 1280kg, and produces 225bhp

Used the following site for reference http://www.jekylhyderacing.com/weight.htm

Total weight 1280kg @ 225bhp = 175bhp per tonne

Fitting FIA seats - 16.36kg saved
Remove Aircon - 20.45kg saved
De-cat - 9.09kg approx saved
Fit lightweight battery - 13.64kg saved
Remove spare tyre and jack - 20.45kg saved
Fit aftermarket exhaust - 13.64kg saved
Approx 80kg total saved

Total 1186kg @ 225bhp = 190bhp per tonne

Was trying to work out how this would tranfer to actual performance, remembered this formula, which I'd always thought was rather dubious

Total Weight
--------------- = 0-60
bhp x 0.9

At 1280kg and 225bhp 0-60 = 6.32 secs
At 1186kg and 225bhp 0-60 = 5.85 secs

Is a half second decrease really realistic? I'm sure some of the track day specialists will have an opinion on this

Ultimately I've come to the conclusion, that even if I lost 2 and a half stone, it would only take about 0.15 of a seconds off my 0-60 time, so I'm off to McDonalds!

[Lauren]

Get your car on a public weighbridge. Its the only way to see what it really weighs.

[craig]

Sounds right though!You go through all this hassle of making the car lighter when it doesn't do all that much!

[Lauren]

I disagree!

Just thought of this, but as you may know i lightened my SC by some 100Kgs. Thats around a 10% reduction in weight. God knows what difference it made to 0-60s etc, it did push the power to weight ratio up somewhat! As it weighed in at 1010kg i had 180bhp/tonne (more than your tubby according to your calculations) The reason i did it was to sharpen the handling and response of the car. this is where it makes the difference IMO.

It wasn't a comfortable car, but when it was on track it worked really well and you could really feel the benefit of losing that extra weight.

[speedy_g]

It's difficult to guess what kind of difference that kind of weight loss would make to the handling and braking of my 2. I have to admit that I have always been impressed with the performance the first elise managed, using only a 118bhp rover engine.

I think it's probably about spending your money in the right places, whilst removing the aircon is essentially "free power" (especially given our weather) I don't see the point in spending a load of money on plexiglass, as I know that even the lightweight glass in the intera costs a small fortune to replace! Then again it is a honda, so you should expect it I guess

[Lauren]

It's difficult to guess what kind of difference that kind of weight loss would make to the handling and braking of my 2. I have to admit that I have always been impressed with the performance the first elise managed, using only a 118bhp rover engine.

I think it's probably about spending your money in the right places, whilst removing the aircon is essentially "free power" (especially given our weather) I don't see the point in spending a load of money on plexiglass, as I know that even the lightweight glass in the intera costs a small fortune to replace! Then again it is a honda, so you should expect it I guess

It all depends what you use your car for i guess. I used to use my old SC mainly for track use so i got rid of anythint that had any weight to it.

One thing that can't be denied is that the lighter a car is the more repsonsive it will be and the quicker it will change direction, so it will definately help the handling. How much of a difference you notice depends upon how much weight you remove and to what level you take your driving.

Also something else i forgot to mention, is that a lighter car is easier on its brakes, suspension, bushes and will use less fuel.

Swings and roundabouts, but there is a lot more than the obvious to be gained by losing weight.

the first elises weighed in at 720Kg!! amazing isn't it? the alacrity with which an elise changes direction is pretty impressive too.

[speedy_g]

I seem to recall one going past me on the dual carriageway in Bath at about 110, when it hit the roundabout at the end it just didn't seem to slow down, the way it went round that thing was astonishing
If i'd have tried that in my 2 I'm sure I'd have ended up upside down in a field

Needless to say that when I change cars, I intend to keep my 2 as a track car, and I will be gutting it. Just don't intend to go to the lengths and costs of fitting carbon fibre doors!

[Frustrated Pilot]

i was thinking about going down the lighter route...

get rid of everything... look how much weight u can save if u loose that heavy engine!!!

get a model 2 stroke.. ... be jus fine

seriously... can be done... but that air con in a tubby in traffic in 30-35 degrees in summer... ID CHOOSE 0.25 sec slower please.. air con is nice

my engrish sucks today.. sorry lads

[Shadow]

Here's my 2p on weight saving for the '2:

I think the weight saving things that speedy_g listed are very much do-able for most people, and it would be beneficial (well myabe not air-con coz thats nice) without any compromises.

But I think it's funny how some people get too caught up in losing weight off their mr2, when it would be far easier to go to the gym and lose some pounds of their own body fat

It's true though, some people go crazy and start ripping out their interior, sound deadening and everything else they don't 'need', if its a pure race car that only see's the track, then fair enough, but if its a road car its just crazy. Its funny when you see someone in a totally stripped out car and their 2 or 3 stone overweight!

I like my creature comforts, the stereo, electric windows, air-con and all that, so I won't be getting rid of that for the sake of an extra 20hp advantage, i'd rather spend a few more £'s and get 20hp extra

Of course i'm not suggesting anyone on this forum is overweight I know weight saving is beneficial for handling, but is it worth sitting in a hot noisey and uncomfortable car for?

Steve

[Lauren]

Here's my 2p on weight saving for the '2:

I think the weight saving things that speedy_g listed are very much do-able for most people, and it would be beneficial (well myabe not air-con coz thats nice) without any compromises.

But I think it's funny how some people get too caught up in losing weight off their mr2, when it would be far easier to go to the gym and lose some pounds of their own body fat

It's true though, some people go crazy and start ripping out their interior, sound deadening and everything else they don't 'need', if its a pure race car that only see's the track, then fair enough, but if its a road car its just crazy. Its funny when you see someone in a totally stripped out car and their 2 or 3 stone overweight!

I like my creature comforts, the stereo, electric windows, air-con and all that, so I won't be getting rid of that for the sake of an extra 20hp advantage, i'd rather spend a few more £'s and get 20hp extra

Of course i'm not suggesting anyone on this forum is overweight I know weight saving is beneficial for handling, but is it worth sitting in a hot noisey and uncomfortable car for?

Steve

My car was a track only car and was generally only driven on the road to get too and from the track, so i stripped mine out. I agree there is no way i could cope with it on a day to day basis, with no sound deadening, carpets or radio (not that you'd be able to hear it!).

Adding power though is not as good as removing weight vis a vis.

I don't need to lose weight btw.

[Dave Goodhand]

I've stripped most of the stuff out of my car, and found it to be better on fuel and more fun! Although damn cold in the current weather!

I like it, but then I'm probably just mad! Losing the aircon is more than just 20kgs - you're probably thinking of just the pump and not everything else that goes along with it.

I only weigh 63kgs, so I'm not overweight either! I prefer the way that with no sound deadening you can hear everything that the engine is doing, and only have a basic stereo - but without it I'd go mad, as do quite a lot of long distance driving in my 2.

To be honest at the end of the day it is your car, and you do whatever you like to it.

[MR2Mania]

Adding power though is not as good as removing weight vis a vis.

I know what you're saying, Lauren, but how much weight would you have to lose to make it equivalent to having 400bhp?

Also, the weight saving isn't the COMPLETE story. Let's take F1. The cars weigh a minimum of 600kg (they could be lighter, but regs say they shouldn't be). HOWEVER, when at speed, they weight over 3 times their normal weight, thanks to Aero. So why are they so concerned with losing weight? Well, the only benefits are really at low speeds when aero isn't effective, and also that, by controlling the weight, they can get it as low as possible. That's why most top F1 cars are actually quite a bit lighter than 600kg, and they make up the weight by ballast that can be placed in strategic places to achieve the balance they want for a given circuit.

Anyway, I'm rambling now...

[PsychomIKE]

Well, if i understand correctly, i disagree about the F1 weight saving...

Yes the f1's can produce ridiculous amounts of downforce when at speed but it is just that. "Downforce" not added weight...

When cornering the tyres are not loaded with transferring 3000lbs with a tyre contact grip of Y lbs.... they are still shifting 600 kgs with a tyre contact grip of Y... downforce can be very misleading..

God i didn't explain that at all well... too many drinks tonight :S

Mike

[MR2Mania]

Well, if i understand correctly, i disagree about the F1 weight saving...

Yes the f1's can produce ridiculous amounts of downforce when at speed but it is just that. "Downforce" not added weight...

When cornering the tyres are not loaded with transferring 3000lbs with a tyre contact grip of Y lbs.... they are still shifting 600 kgs with a tyre contact grip of Y... downforce can be very misleading..

God i didn't explain that at all well... too many drinks tonight :S

Mike

No, you didn't!

Downforce is downforce, mate - exactly that, ie FORCE, ie WEIGHT!

And we're not even taking into account the extra drag from converting air speed into downforce.

Bottom line is, those wide tyres don't work unless they've got some severe weight on them.

Did you see a feature that "5th gear" did a little while back, running Jenson's BAR against a racing bike against a powerboat? The F1 car was pretty level with the bike up until about 70-100mph, and then all of a sudden, once the downforce started coming into play, it left the bike for DEAD!

4G cornering, anyone??

[Shadow]

I don't need to lose weight btw.

I only weigh 63kgs, so I'm not overweight either!

Like I said I wasn't implying that people who save weight on their cars are all big heffa's, I was just saying that if you was overweight and wanted a lighter car then the gym would be the first thing to do

Losing the aircon is more than just 20kgs

Hmm does 20kgs make that much difference!? Maybe its just me, but I can't tell the difference in handling/performance if I have a passenger or not, so I doubt i'd notice 20kgs......and like you said I bet your a bit cold lately

Still each to our own, if you think you notice a difference, then go for it.

Adding power though is not as good as removing weight vis a vis.

I guess that's a fair statement, as reduced weight is beneficial in more ways than increasing hp per tonne, but in my opinion it would be cheaper to increase the hp than reduce the weight by a significant amount (i.e. so you can actually feel the difference) as once you get past the getting rid of stuff phase you have to start looking at expensive stuff like carbon fibre this and that, superlight alloys, and all the rest.....where you could just by a boost controller and up your boost, or buy some nitrous

Give me air-con, eletric windows, power steering, a full interior and 500hp and that'll do me nicely

[Lauren]

Adding power though is not as good as removing weight vis a vis.

I know what you're saying, Lauren, but how much weight would you have to lose to make it equivalent to having 400bhp?

Also, the weight saving isn't the COMPLETE story. Let's take F1. The cars weigh a minimum of 600kg (they could be lighter, but regs say they shouldn't be). HOWEVER, when at speed, they weight over 3 times their normal weight, thanks to Aero. So why are they so concerned with losing weight? Well, the only benefits are really at low speeds when aero isn't effective, and also that, by controlling the weight, they can get it as low as possible. That's why most top F1 cars are actually quite a bit lighter than 600kg, and they make up the weight by ballast that can be placed in strategic places to achieve the balance they want for a given circuit.

Anyway, I'm rambling now...

Dino, come on comparing F1 is totally and wholly irrelevant!

Get a ride in a high powered caterham or a honda engined elise and you'll see the benefits of a very light car. A supercharged atom for example has a power to weight of around 600bhp/tonne.

[MR2Mania]

Dino, come on comparing F1 is totally and wholly irrelevant!

LOL! I know, Lauren. Just trying to point out that it's not so much reducing weight, but also about balancing and lowering the weight. You know me. I always use F1 as an example - after all, it's the pinnacle of motorsport and engineering.

I still think, though, that the majority of people would be better off getting more power out of the engine (particularly if they have a tubby) than removing all the "luxuries". As someone already noted, they'd be hard pushed to notice the difference in handling.

Get a ride in a high powered caterham or a honda engined elise and you'll see the benefits of a very light car. A supercharged atom for example has a power to weight of around 600bhp/tonne.

Yeah, I really should, but I haven't been *near* a track lately.

Gotta get my priorities straight!

[Lauren]

I agree that tubby owners may as well concentrate on increasing power as its not worth losing the luxuries if its a road car.

Also you are never going to get a mega power to weight in a car that weighs 1300kgs at least.

You and F1 eh? FTLOG!

[EarL]

FTLOG!

What the hell is FTLOG?

[Lauren]

FTLOG!

What the hell is FTLOG?

sowwy= For The Love Of God