Griff on a diet

[steve-v8s]

Is there any useful benefit to losing a bit of weight ? The Lotus boys all remove everything they can before competition but they are four cylinders short of an engine. I figure that removing the radio, speakers, front carpets, washer bottle water and passenger seat I can loose about 25-30 kg ( which is all I can think of that can be easily removed and re fitted ). Is that worth bothering with on a sprint ? At the last event I was short of 0.02 secs.

[joospeed]

I'd say remove anything you can .. including the roof on venues where the average speed is relatively low .. the weight reduction will only be offset by the poorer aerodynamics at higher speeds ..

[julianhj]

Saw the TMS racing Griff at Brunters last year, and that looked very bare. Is this just an occasional thing, or full time racer?

>> Edited by julianhj on Monday 26th July 18:00

[shpub]

First thing is to check what the regs will let you remove. Don't want to get reclassified etc. If the car is not road legal you may be asked to supply an MSA log book. Strictly speaking that means if you remove someing like the washer bottle itself, you are not road legal and fall foul. Pretty sure you can't remove the passenger seat but it is very reg dependent. Nothing to stop fitting a couple of racing seats which will be lighter.

As for removing the roof... Don't even think about it. On the 520 when it was a 390 removing the roof added about 0.5 seconds to the 0-60 time and knocked about 15-20 mph off the top speed.

Steve
www.tvrbooks.co.uk

[GreenV8S]

steve-v8s said:

Is that worth bothering with on a sprint ? At the last event I was short of 0.02 secs.

Not unless there is a large amount of money resting on the result and you had no other options. Choosing the right line, improving your driving technique and fine tuning the car setup can make far far more difference than this.

[stesrg]

you could go on a diet

[steve-v8s]

Thanks for the comments. I concur about not removing the roof, I have driven the local hill enough times to get fairly consistent 64 ft times and then it is a straight line to the first speed trap. With the roof on it is a repeatable 84mph and 77with it off. I feel that folding the mirrors in also helps as they present a smaller profile that way.

I also agree that the most effective way of getting my car to go quicker is to replace the incompetent driver. OK about the diet, I will only have the one bacon roll after first practice then.

Does anybody have a more scientific analysis of acceleration compared to power to weight ratio. ? there must be a simple formula to apply.

[shpub]

It is about power to weight. 250 bhp in a 1000kg car gives 250bhp per ton. 250 bhp in a 990 kg car gives 252.5 bhp. It is like giving the car another 2.5 bhp. It also can help with the balance if the weight is at the extremity of the car as it reduces the pendulum affect.

Having said that, weight reduction is all about compromising the car. If it is a full blown racer get stripping the interior.
However I would also bear in mind reliability. The less the mechanical bits are touched the better.

Will it help get that 2/100ths back? Yes but equally the driver can make a big big difference as well.

If you want to save 20 kg at a stroke replace the battery with a race gel type. Red Top 20 is fine. About £100. However, lets get back to the compromise... the battery is not big on capacity and doesn't like having a small drain current like from an alarm. It will flatten and die quickly in such conditions. I have a master switch to disconnect it and plug a conditioner on. I also use two in parallel to get the capacity for normal driving but remove one when competing.

Talk to John Eales and he can sell you a lightened clutch/flywheel/strater motor for around £1500 that will save another 12 kg. A race alternator will save about 2 kg and cost about £250.

The car will require cornerweighting after the weight reduction BTW.

[steve-v8s]

Steve
Thanks for reminding me about the battery. I looked at fitting a Red Top before to gain some extra leg room. Is it OK to simply connect them in parallel ? I would of thought they would discharge into each other. Have you mounted them together or is one in the boot / behind the seat ?