30kg overweight. consequences?

[beqa16v]

Hi guys.
I am racing in an Alfa engined single seater mono series in Georgia. Currently my car (together with myself) is 30kg (66lbs) over the minimum allowed weight. Minimum is 635kg and my car weights 665. What are the consequences, obviously it slows you down but by how much?
Track is very fast, mostly fast corners and straights.

[andrewc]

Yes, there will be the consequence of accelerating, braking and cornering the extra weight, and in terms of chassis balance, but many a race and championship has been won by a car that is a bit lardy and the people to regularly complain about weight usually have other things they could improve on.

You'll just have to counter the weight deficit by intelligent car preparation and superior driving and try to reduce weight where it can be reduced.

Eg consider switching to a lithium battery rather than a traditional one.

[beqa16v]

Originally Posted by andrewc

Yes, there will be the consequence of accelerating, braking and cornering the extra weight, and in terms of chassis balance, but many a race and championship has been won by a car that is a bit lardy and the people to regularly complain about weight usually have other things they could improve on.

You'll just have to counter the weight deficit by intelligent car preparation and superior driving and try to reduce weight where it can be reduced.

Eg consider switching to a lithium battery rather than a traditional one.

True I need to improve in other departments first of all as I am new to single seater racing.
But I would be happy to know how much time can I approximately gain on a 1min 50sec track by dropping around 25 kilos.

[andrewc]

I would think maybe 0.5 to 0.75 of a second.

[greenamex2]

Think yourself lucky, my car is 100-150 Kg overweight!

Depends what the extra weight is doing. If it is doing nothing useful then it is probably costing 0.25-0.5 seconds at the most. If is contributing to the cars performance, such as stiffening the chassis, producing more power, improving the suspension etc then the difference is negligible.

Also depends where the extra weight is.

[tristancliffe]

Depends on lots of factors, but I'd be surprised if 30kg slows you by more than 0.3 seconds, and probably less. But it's a good excuse, and since F1 started talking fuel weight penalties, it's a very common "I could go faster if...".

Probably more of an issue is how it effects the weight distribution of the car, and what influences that places on the setups.

[beqa16v]

Thanks a lot guys.
Speaking about weight distribution, these formula alfa cars have hevay engines. as a result the weight distribution is 41 - 59 rear. The car has horrible lift off oversteer at high speeds and is very tricky to drive in fast corners. It is slicks and wings car. Do you think balance will be better with a bit more weight transferred to the front (eg battery relocation which is currently in the rear).

[Al Weyman]

This discussion of weight and where it is is interesting to me. I can shed 40 odd kilos from one of my cars merely (makes it sound easy, its not!) changing the rear steel and 9mm glass rear hatch to Lexan and aluminium but have often wondered will it be worth the effort. OK accelleration and speed down the straight will be improved but will traction suffer as the weight bias will move even more forward so no real gain or should i just get on and do it?

[beqa16v]

Originally Posted by Al Weyman

This discussion of weight and where it is is interesting to me. I can shed 40 odd kilos from one of my cars merely (makes it sound easy, its not!) changing the rear steel and 9mm glass rear hatch to Lexan and aluminium but have often wondered will it be worth the effort. OK accelleration and speed down the straight will be improved but will traction suffer as the weight bias will move even more forward so no real gain or should i just get on and do it?

From what i know more weight at the front will give you more "inertial" understeer, mostly in faster corners. heavier side struggles to turn under high lateral G more than the lighter side.
Traction is another thing. you will probably have less of it coming out of slow corners if it is RWD.

But anyway, more experienced guys have to comment if this is valid.

[morninggents]

Based on my own car which I have raced for over 20 years (front engine/RWD/historic saloon) I reckon you would save almost 1 second on a 1-50 lap by losing 30 kg. I have been through the adding lightness cycle then the opposite of having to add weight when Tech Regs changed and, being a bit anal, kept records over the same circuits over several seasons.

The additional weight affects braking and handling as well as acceleration.

Redistributing weight to the front in a heavily rear weight biased car will help in the handling and braking departments.

[Adam43]

Originally Posted by tristancliffe

Depends on lots of factors, but I'd be surprised if 30kg slows you by more than 0.3 seconds, and probably less. But it's a good excuse, and since F1 started talking fuel weight penalties, it's a very common "I could go faster if...".

Probably more of an issue is how it effects the weight distribution of the car, and what influences that places on the setups.

Weight distribution is important, but if I had perfect distribution and had the opportunity to lose 30kg from one end of the car I would lose the 30kg.

[beqa16v]

Thanks for all the answers guys.
I was testing the car on a skidpad today, just for fun. Here is the onboard video
http://www.youtube.com/watch?v=fYTCq...ature=youtu.be

[GORDON STREETER]

Originally Posted by beqa16v

Thanks for all the answers guys.
I was testing the car on a skidpad today, just for fun. Here is the onboard video
http://www.youtube.com/watch?v=fYTCq...ature=youtu.be

I noticed you had all the safety gear on !

[Al Weyman]

Well I am going to save a fair bit of weight now, I thought I would gut the doors out on the 3rd Gen Camaro last weekend and ops, I broke a door glass so now its going the whole hog with plastic windows as well as e rules now allow and I have ordered the material today (4mm PETG sheet seems the material of choice for this job). Depending how I get on with this and fortunately I managed to get the other side glass out whole so I have a pattern I may have a go at the rear hatch during the winter but thats quite an undertaking. The doors with SIP bars are hugely heavy so I recon I will get a healthy few pounds off from them alone with the plastic side windows.

[Goran Malmberg]

First I want to say that the significance of extra weight on the car have, depending on where it is placed. Someone mentioned that it can be placed so that a more even weight disrtibution is obtained, but it is not clear that uniform distribution improves lap times. It does, however the car easier to understand attitude-wise. As for weight distribution in general (not extra unnecessary weight) if we got a powerfull engine, more rear weight distribution will help acceleration. It also helps braking. If the extra weight is located under the CGH, it can possibly be helpful. Similarly, if it is placed laterally so that it helps an unbalanced car for better balance. Would the weight however sit on the roof of the car, it becomes a pure destruction.

[Al Weyman]

I think I agree with that last sentence and will take the plunge in the closed season to rid my car of the enormously heavy rear hatch which weighs over a 100lbs I have read. I do actually feel it trying to throw the rear out like a pendulum. There is still a lot of weight to come off this car.