i often buy Fast Ford magazine as I quite like cosworths and some old school Fords. Please don't laugh!

Anyway, Ithought a few of you may be interested in this...

They have a very good test in this month's edition. They have a tuned Fiesta ST that is running 215bhp. They changed the standard ST wheels for Team Dynamic Pro Race 1.2s which are altogether 12kg lighter. They mention that 12kg unsprung weight is equivalent to around 48kg weight saving from the chassis. They undertook 4 tests -

Test 1 - Braking. 60-0mph and 100-0mph
Test 2 - Handing. A timed lap around a circuit
Test 3 - Standing start acceleration to 60mph
Test 4 - In gear acceleration. 30-80mph

Results - All tests were performed 3 or 4 times and the times were then averaged. Results were gained using a Racelogic Performance Box.

Test 1 - Before 60-0 = 3.2s Before 100-0 = 5.3s G = 0.97
After 60-0 = 3.0s After 100-0 = 4.8s G = 1.07

Test 2 - Before = 1:28.6 After 1:24.3

Test 3 - Before 0-60 = 6.9s Before 0-100 = 17.8s Quarter mile = 15.7 @ 94mph
After 0-60 = 7.4s After 0-100 = 18.0s Quarter mile = 15.9 @ 94mph

Test 4 - Before 30-80 = 8.8s After 30-80 = 8.3s


I'm sure you'll agree there is some intersting results there. Quite a difference on the timed circuit. They said they thought the 0-60 times were down on the standard wheels as there was less mass for the engine to turn, therefore the wheels tended to spin more when applying the accelerator.

Hope this is of some use to some people!

Nick

 

Yeah removing unsprung weight is good for a host of reasons.

My mate used to own a fiesta ST good little handling cars, however i really dont believe that removing this amount of weight 'alone' will reduce the 0-60 by 0.5 seconds and the 1/4 by 0.2 seconds - that a good car length probably 2.

I'd question the test and sponsor .

 

0-60mph was slower Irvatron. they said that because the wheels were easier to rotate, they couldn't get traction, thus the 0-60 times were .5s slower than standard.

 

Sorry i skim read

 

Do Team Dynamics sponsor the magazine?

 

Weight saving (and the consequent optimum ballast positioning in minimum weight restricted series) is always of paramount importance, and the rule of thumb I have always been told is unsprung weight saved is equivalent to double in sprung weight.
Even as far back as 15 years ago we had a measure of value of £1000/lb i.e. if it cost less than £1000 to save 1lb then it was worth doing.

 

Not as far as I'm aware. They said in the article that they picked the TD 1.2s as they were one of the easiest 'lighteight' alloys for people to get a hold of.

 

 

I ran these on my previous car and was very impressed with them. Turn in was sharper, braking felt sharper and acceleration seemed perkier with them on - you can't rely on bum dyno though so it's good to see figures in black and white.

 

Interesting. Less unsprung mass means the suspension can react faster and give you more grip on rough roads, which is where the braking and probably the lap time benefit comes from (and it also makes for a nicer ride). I wonder if that can make things worse on a standing start?

What we should all do is run 15" wheels. The standard 15"x7" alloys that were on my Primera were amazingly light, much lighter than those fancy 16" JDM BBS S2000 wheels.