Board logo

Specs and Figures Needed
Jermyn - 17/2/05 at 03:14 PM

I'm finding that reading the chassis books without actually having some real world numbers to crunch for the calculations is difficult.

I'm a hands-on type of learner so I need to actually equate some examples for it to sink in to my thick skull.

Since everybody's car is different I was hoping everyone could offer up some figures on their actual car (or what they expect their car to be)

Total car weight
Center of gravity height
Car track width
weight distribution front/rear
Static weights at each tire

middie specs welcome as well

kb58 - 17/2/05 at 03:22 PM

What are you going to use the data for? Every one's car will be different, most won't know all of what you want to know. If you're running the numbers through "CarTest" just modify one that's already in it.

Jermyn - 17/2/05 at 03:39 PM

I want to use the figures to calculate lateral weight transfer to determine the traction available so I can figure the total cornering force.

It's really just an exercise to figure over and understeer.

What's "Car Test?"

Fifer - 17/2/05 at 03:45 PM

cornering force = head bending over to one side and wheels smoking

kb58 - 17/2/05 at 04:04 PM

CarTest is a free downloadable program that simulates car performance (in a straightline unfortunately.) You can change all the parameters to try out various "What if" scenarios, which is what I used to calculate my mid-engine Mini "should" do about a 12.7sec 1/4 mile time.

As said before, everyone's car will be different, tires will make a huge difference on your results. Why not just use the book dimensions and go from there?

krlthms - 17/2/05 at 04:50 PM

quote:
Originally posted by kb58
CarTest is a free downloadable program that simulates car performance (in a straightline unfortunately.) You can change all the parameters to try out various "What if" scenarios, which is what I used to calculate my mid-engine Mini "should" do about a 12.7sec 1/4 mile time.

As said before, everyone's car will be different, tires will make a huge difference on your results. Why not just use the book dimensions and go from there?


I would have thought your car would do better than that. Is it being limited by the (lack of) aerodynamics of the Mini body?
KT

kb58 - 17/2/05 at 04:54 PM

No, 1/4 time isn't affected *too much* buy aero drag. It's simple the total weight, 1650lbs, pushed by 160whp.

Most cars aren't as fast as they are on paper, but I think my 12.7 number is realistic. If I'm wrong and it's faster I'll be a happy camper.

Jermyn - 17/2/05 at 05:26 PM

quote:
Originally posted by kb58
CarTest is a free downloadable program that simulates car performance

As said before, everyone's car will be different, tires will make a huge difference on your results. Why not just use the book dimensions and go from there?


If the program is free, I'd like to try it. Do you have a site for download? However if it only calculates straight-line accelleration performance it would be fun to try but I'm looking to calculate how any given car would perform in cornering situations.

Since everyone's car specs will be different I should get plenty of practice figuring these and therefore have a better grasp on the math equasions.

I agree that tires will play a large role in determining the end result, but if I start off with good chassis design then better tires will only make it the betterbestest

The reason I'm not using just the book chassis is because I'm contemplating on building a Middie. So, I'd like to do some calculations on both.

scoobyis2cool - 18/2/05 at 01:54 PM

I've used this program before and found it pretty interesting, not sure how accurate it is but it's still fun to pit your car against a GT40 around the Nurburgring

Unfortunately I formatted my computer recently and forgot to save the program, any ideas where I can download it?

Cheers

Pete

flak monkey - 18/2/05 at 01:57 PM

This the one?

http://www.cartestsoftware.com/cartest2000/index.html

David

[Edited on 18/2/05 by flak monkey]

scoobyis2cool - 18/2/05 at 02:00 PM

Wow that was fast! I just found that site myself, haven't got time to look through it at the moment but seems to be a newer updated version of the software.

The older DOS software can be downloaded for free HERE

Pete

kb58 - 18/2/05 at 03:24 PM

That's it.

The cool thing is you can play around with hp and weight just to see what'll happen. I found it particularly interesting creating a front-engine car, checking it's performance, then moving the engine back to a mid-engine position without changing anything else. The shift of CG does wonders for acceleration.