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Holden Time Attack Concept.


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#51 Greg Locock

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Posted 25 October 2018 - 21:19

Depends on whether it is 2wd or awd.



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#52 gruntguru

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Posted 25 October 2018 - 21:53

. . .  max cornering is enabled when all four tyres have their force vector pointing in the same direction (relative to steer angle). . . . .

 

. . . . ultimate cornering grip occurs when each tyre provides lateral grip in proportion to its vertical load AND longitudinal grip in proportion to its vertical load. . . . . 

 

A third and final consequence (within reasonable limits) - each tyre will be operating at the same slip angle (lateral grip) and the same slip % (longitudinal grip).



#53 Lee Nicolle

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Posted 27 October 2018 - 03:50

The diffs are the beiggest contributor.When you set the meshing (in production) there's a horrible compromise. Ideally for fuel consumption you'd like perfect mesh at a fairly low torque. but that implies a poor mesh at high load. That means lots of heat. Diff oil has a very hard life as it is, and you'd end up burning the oil if you were towing up a hill if the mesh was set for the 'ideal' for fuel consumption

So many forget the drive axle. They can burn oil big time and destroy them selves. And drag a lot of power as well. Ford 9" a glaring example. A bloody great innefficient lump that is way too heavy! And for all that drool over them has not been made since about 1978!

As for drive actuation? Whatever anyone says a spool is simple and reliable and generally better than all the fancy electronic crap. Though some these days when working properly is possibly better.

Electric Motors on the wheels is simply unsprung weight.  Independent suspension ofcourse and engine can mate straight to trans. Any form of motivation will always be as we know now. Engine location can be more efficient but they still need cooling so hidden under the car for a practical road vehicle is not the way. For a Time Attack car rear mounted motors would be the best, but not for longevity. This ofcourse is for all types of engine. What is practical for time attack is not practical for anything else.

4WD ?  Should be considered even with the weight penalty, depends on the track. Tight and twisty yes, Open and flowing No. Remember we are talking one or two lap screamers. where the tyres should live.



#54 pierrre

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Posted 05 November 2018 - 18:37

Really?

if there is a lot of power and torque four wheel drive will prevail. say if there is an added 200 horspower and a certain amount of torque at the front wheels to a four wheel drive...thats how much a loss it is for a rear wheel drive only vehicle in traction...then there is driving styles, todays driving style which revolves heavily around acceleration utilizing slow in fast out..that would be advantageous if a four wheel drive system was used



#55 MatsNorway

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Posted 06 November 2018 - 21:05

Yet Audi managed to win in Touring cars with a 2L NA engine running 4WD, they had only 300hp give or take in a 1070kg car. The ultimate time attack vehicle discussed here could be about half the weight with three times the power. Just like in Top Fuel, losses becomes irrelevant as long as it goes faster.


Edited by MatsNorway, 06 November 2018 - 21:25.


#56 gruntguru

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Posted 04 June 2019 - 06:04

https://www.roadandt...p-record-video/

 

VW EV goes 6:05 at Nurburgring.



#57 Lee Nicolle

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Posted 16 June 2019 - 09:30

So, if we could design a car that races on a circular track only and the fastest time for one flying lap determines the winner, how would the car look like if downforce is not allowed.

I'd start with a 50:50 weight distribution front to rear, a weight distribution of maybe 55:45 to the left (for a lefthand track) so that the dynamic lateral distr. is close to 50:50. Add individual steering to all four(or 6 or 8) wheels and power all wheels individually, too. Tyre size should be same for all wheels. The suspension is either active or designed in a way that the car is parallel to the ground during cornering. Aerodynamic drag should be minimised as high drag reduces the remaining tyre forces.

A circular track with equal size tyres? You will have to drive quite sideways which is shitloads of power drop. Or the car goes straight ahead,, not around the corner. 

Look at the attitude of a Nascar, they have little stagger and a fair bit of inside weight.IF they had more stagger they would be faster. And yes they are not very fast for all the money spent. Look at so many forms of speedway and you realise that better racecars are a good deal faster and use a good deal more stagger to acheive the speed.

A decent AWD car with a lot of setting up would be quite fast but long term too heavy and too hard on all of the transmissions.Gearbox,.centre diff, front and rear diffs You are talking mega dollar rally cars.