Losing Weight

[Aerotop Dave]

Has anyone actually worked out the performance gains though? Something like each kilo representing 1/10th of a second quicker over 1/4 mile, or 2mph more top speed (as a totally non-worked out and unscientific example).

 

If the net effect of all this effort is 0.2 second faster to 60mph it might not be worth the bother.

[lust2luv]

Well if you managed to save, say 50kg from a 1600kg fully loaded car, that would equate to around a 3% weight saving. So would presumably have a similar effect to a 3% HP increase. Doesn't really seem worth it when you think about (other than reducing unsprung weight), unless you're seriously into drag racing.

 

[Digsy]

Has anyone actually worked out the performance gains though? Something like each kilo representing 1/10th of a second quicker over 1/4 mile, or 2mph more top speed (as a totally non-worked out and unscientific example).

 

If the net effect of all this effort is 0.2 second faster to 60mph it might not be worth the bother.

You can make an estimate using some broad assumptions.

 

Force (N) = mass (kg) x accereration (m/s^2), so

 

Acceleration = Force / mass

 

Take your 1/4 mile time from Pod and work out the average acceleration using:

 

a = v^2 / (2 x s)

 

Where:

v = terminal velocity at 1/4 mile mark (converted to m/s)

2 x s = 2 x 1/4 mile (converted to m) = 2 x 402.3 = 804.6m

 

OR

 

Use your 0-60mph time to do the same thing using:

 

a = v/t

 

Where:

t = 0-60 time in seconds.

v = 60 mph (converted to m/s) = 26.8m/s

 

THEN

 

Make the assumption that traction will not be affected (even though it might be if you take a lot of weight off the rear wheels).

 

AND

 

Weigh your car as it was when these measurements were taken before you start unbolting bits!

 

So, initially (before weight reduction), all masses in kg:

 

F = m1 x a1

 

...and after:

 

F = m2 x a2

 

...so:

 

m1 x a1 = m2 x a2

 

...and:

 

a2 = (m1 / m2) x a1

 

m1 / m2 is the ratio of old weight to new weight (in kg). So if you expect a 10% weight reduction, then (m1 / m2) will be 1.11 For 5% it will be 1.05 etc.

 

..which is a bloody long winded way of saying that its linear. If you make a 10% reduction in weight, then your acceleration should increase by 10%, which should in turn reduce your 0-60 time by 10%

 

A better way of writing it is to subsitute m2 for [m1 - dm], where dm = the actual weight reduction, so:

 

...so (finally):

 

a2 = (m1 / [m1 - dm]) x a1

 

...and before any smart-arses tell me that kg is a measure of mass, not weight. I know! I know!

[Bobbeh]

Jesus christ, I'd just say if you were thinking of a new exhaust and wanted weight savings, then Ti would be a wise choice, no?

[daz38]

i would liked to put some weight on, wheres a good place to get a body kit, my supra aerotop is to standard and how much.

[Bobbeh]

Check out the various companies/traders in the sales section.. you have a good selection

[Matt Harwood]

You can make an estimate using some broad assumptions.

 

Force (N) = mass (kg) x accereration (m/s^2), so

 

Acceleration = Force / mass

 

Take your 1/4 mile time from Pod and work out the average acceleration using:

 

a = v^2 / (2 x s)

 

Where:

v = terminal velocity at 1/4 mile mark (converted to m/s)

2 x s = 2 x 1/4 mile (converted to m) = 2 x 402.3 = 804.6m

 

OR

 

Use your 0-60mph time to do the same thing using:

 

a = v/t

 

Where:

t = 0-60 time in seconds.

v = 60 mph (converted to m/s) = 26.8m/s

 

THEN

 

Make the assumption that traction will not be affected (even though it might be if you take a lot of weight off the rear wheels).

 

AND

 

Weigh your car as it was when these measurements were taken before you start unbolting bits!

 

So, initially (before weight reduction), all masses in kg:

 

F = m1 x a1

 

...and after:

 

F = m2 x a2

 

...so:

 

m1 x a1 = m2 x a2

 

...and:

 

a2 = (m1 / m2) x a1

 

m1 / m2 is the ratio of old weight to new weight (in kg). So if you expect a 10% weight reduction, then (m1 / m2) will be 1.11 For 5% it will be 1.05 etc.

 

..which is a bloody long winded way of saying that its linear. If you make a 10% reduction in weight, then your acceleration should increase by 10%, which should in turn reduce your 0-60 time by 10%

 

A better way of writing it is to subsitute m2 for [m1 - dm], where dm = the actual weight reduction, so:

 

a2 = (m1 / [m1 - dm]) x a1

 

...so (finally):

 

a2 = (1 - [m1 / dm]) x a1

 

...and before any smart-arses tell me that kg is a measure of mass, not weight. I know! I know!

 

 

Talk about stating the obvious!

[Nic]

You can make an estimate using some broad assumptions.

 

Force (N) = mass (kg) x accereration (m/s^2), so

 

Acceleration = Force / mass

 

Take your 1/4 mile time from Pod and work out the average acceleration using:

 

a = v^2 / (2 x s)

 

Where:

v = terminal velocity at 1/4 mile mark (converted to m/s)

2 x s = 2 x 1/4 mile (converted to m) = 2 x 402.3 = 804.6m

 

OR

 

Use your 0-60mph time to do the same thing using:

 

a = v/t

 

Where:

t = 0-60 time in seconds.

v = 60 mph (converted to m/s) = 26.8m/s

 

THEN

 

Make the assumption that traction will not be affected (even though it might be if you take a lot of weight off the rear wheels).

 

AND

 

Weigh your car as it was when these measurements were taken before you start unbolting bits!

 

So, initially (before weight reduction), all masses in kg:

 

F = m1 x a1

 

...and after:

 

F = m2 x a2

 

...so:

 

m1 x a1 = m2 x a2

 

...and:

 

a2 = (m1 / m2) x a1

 

m1 / m2 is the ratio of old weight to new weight (in kg). So if you expect a 10% weight reduction, then (m1 / m2) will be 1.11 For 5% it will be 1.05 etc.

 

..which is a bloody long winded way of saying that its linear. If you make a 10% reduction in weight, then your acceleration should increase by 10%, which should in turn reduce your 0-60 time by 10%

 

A better way of writing it is to subsitute m2 for [m1 - dm], where dm = the actual weight reduction, so:

 

a2 = (m1 / [m1 - dm]) x a1

 

...so (finally):

 

a2 = (1 - [m1 / dm]) x a1

 

...and before any smart-arses tell me that kg is a measure of mass, not weight. I know! I know!

 

Okay so who is going to work out what a 50kg weight reduction equates to?

[Matt Harwood]

In terms of straight line acceleration, I think you'd need to lose quite a bit of weight to really make a noticable difference.

 

A few years back, at TSC2, I took Alex up the strip in my auto. The run with him in the car was my second fastest of the day, (12.9 ish), and my top speed was 2 mph down on my fastest...

 

So, you'd have to remove a fair bit of weight to equate to the weight of a person, and from what I experienced that day, it didn't make too much difference. I'm sure every little counts, and sooner or later it will have an effect.

[MONKEYmark]

Jesus christ, I'd just say if you were thinking of a new exhaust and wanted weight savings, then Ti would be a wise choice, no?

dont forget when you stick on some of the heaviest wheels out there

 

what do the blitz wheels weigh 26kg each?????????

[MONKEYmark]

dont forget when you have passengers the car seems sluggish. i have had 3 other passengers in supra and the speed was not there. i was wondering what was wrong with car. dropped the rear passengers off and it made such a difference. i started stripping some weight out of my car as i was bored one day and had a socket set out

 

i have a JDM auto hardtop, mine is a very basic tt (from new)

 

no cruise control

no lsd

no front active aero spoiler

no lsd/diff cooler

no stock amp

no leather front seats

 

 

just started to strip weight off my supra because i was bored one day. does getting weight down make much a difference. i do drag racing a lot when i can. i think the quoted stock weight of a JDM supra i have seen in spec lists is 1550 kg = 3410 pounds. would like to see what mine weighs been a basic spec JDM Supra TT

 

done below so far

 

 

Toyota Supra Weight Reduction

(JDM Supra Hardtop)

 

WEIGHT REMOVED

 

Rear Seats (Top & Bottom)

Rear Seat Belts + Fittings

Rear Boot Carpet

Rear Boot Plastic Trim

Rear Strut tower Tops x2 (Heavy Steel)

Ariel Filled & Ariel Motor Removed

Airbags x2

Front Tow Brackets

Stock Intercooler + All piping

Stock Airbox

Floor Mats x4

Front Crash Bar

Bonnet lining

Under trays

Stock exhaust + cats

2x air vents removed for install of gauges.

 

 

WEIGHT ADDED

 

CUSCO type OS strut braces (front & rear)

BLITZ fmic

BLITZ nur spec cat back exhaust

BLITZ induction kit

2x de-cat pipes 2.5”

2nd Stock Bov (twin bov mod)

FMIC cooling plate (top)

AQUAMIST water injection kit

PHR line lock kit

HKS boost & egt gauges in air vents

 

 

TO DO LIST

 

Remove radio & speakers

Remove stock traction (have RACELOGIC)

Remove fuel canister

 

Also will look into other things I could remove

 

here is a big thread on supra forums, some hardcore weight savers out there.

what are the stock weights of UK/JAP supras 1550kg? 3410 pounds

 

could do a lsit of weights of supras in drag thred if anyone gets to weighing there car?

[Elliot]

try

 

http://moreboost.org/weights.htm

 

and

 

http://suprahardtopregistry.com/

[Bobbeh]

dont forget when you stick on some of the heaviest wheels out there

 

what do the blitz wheels weigh 26kg each?????????

 

Oh shut up.

 

I still have my stock 17s for more serious racing. I bought the Blitz wheel because they look the bollocks, for no other reason. What would be more stupid is if I invested in a SS exhaust too

 

Scooter weighed his and they didnt differ much from the stock 17s anyway.

[MONKEYmark]

Oh shut up.

 

I still have my stock 17s for more serious racing. I bought the Blitz wheel because they look the bollocks, for no other reason. What would be more stupid is if I invested in a SS exhaust too

 

Scooter weighed his and they didnt differ much from the stock 17s anyway.

you not curious as to how much it weighs. your exhaust is a nice weight saving. do you know if the 26kg weight is correct per wheel.

[Sharpie]

Since the topic is losing weight, would it be better to stay with J-spec brakes over the bigger stock ones ?

 

Unless, a BIG brake kit is lighter anyway....?

[MONKEYmark]

Since the topic is losing weight, would it be better to stay with J-spec brakes over the bigger stock ones ?

 

Unless, a BIG brake kit is lighter anyway....?

are 2pot jap brakes the same as what the americans refer to as N/A brakes.

a set of CW fast road pads supposed to move jap spec brakes up a notch with race fluid and s/s brake lines

[Nic]

Since the topic is losing weight, would it be better to stay with J-spec brakes over the bigger stock ones ?

 

Unless, a BIG brake kit is lighter anyway....?

 

No definitely UK or aftermarket brakes, my idea of the thread was whether weight could be saved without compromising comfort and performance. J-Spec brakes although may be lighter would compromise performance.

 

Seems the most beneficial mods would be:

1. Dump heavy stock twin set up and fit single turbo kit (:insert shameless plug for Terry: )

2. Swap front seats for lightweight alternatives.

3. Light weight Mag wheels.

4. Light weight coil over suspension.

5. Remove active spoiler/mechanism.

6. Full titanium exhaust system.

Anyone want to take a guess at what this would save?

 

There will be performance parts that you'd probably want to fit that would add to the stock weight:

1. Swap SMIC for FMIC

2. Bigger brakes

3. Strut braces

 

Overall probably a lot of money for very little weight reduction, but still worth considering when changing things like wheels, shocks, exhaust, etc.

[Bobbeh]

you not curious as to how much it weighs. your exhaust is a nice weight saving. do you know if the 26kg weight is correct per wheel.

 

The wheels dont often come off my car (excluding tyres), and when they do I dont usually have a set of scales handy with which to weight them.

 

I couldnt care less how much they weighed, like I said I bought them purely for looks. I have the choice if I want. I guess you missed my thread when I was looking for race tyres for my stock 17's.

 

(Best ask Scott / Scooter re: the weights, he'd know more than I)

[Alex]

Could of got you some complete carbon doors recently...but you'd have had to buy the rest of the JGTC kit! lol

 

I believe a full Brembo setup actually weighs less than the UK setup mainly due to the ali bells on the disks and obviously the race bred nature of the calipers.

[Guest Terry S]

Hands up who thinks Digsy needs to get out more

[Digsy]

Hands up who thinks Digsy needs to get out more

I was out last night.

 

With Angie and Soop Dogg.

 

 

 

 

 

 

 

We talked about pumping losses

[Guest Terry S]

I was out last night.

 

With Angie and Soop Dogg.

 

 

 

 

 

 

 

We talked about pumping losses

 

LMFAO, now it wont just be Dude's shirts that people avoid at the next Crimbo Party

[Digsy]

Okay so who is going to work out what a 50kg weight reduction equates to?

Give me a typical weight for the Supra and a typical 0-60 or 1/4 mile time and I'll do it

[Guest Terry S]

1490 kg

[lust2luv]

1490 kg? Wet weight, with driver? Unlikely! (unless you're talking SZR or post-drastic weight reduction)