Breaking my car

[adamnreeves]

Adam could easily go 1 second quicker or even more perhaps       but how much of that is down to weight reduction or simply gaining more experience ? who knows

I have got one second left in me.

[adamnreeves]

    too much theory, there's no substitute for spending time with yer   firmly in the seat whether that is driving in a straight line or around bends    

You looked out the Window. Can only theorise at the moment.  

[adamnreeves]

I would love to think that I could get in to the mid 11 seconds runs with road tyres on but with a good bit better PWR than Adam the best I have managed so far is 12.2 at 124mph with slicks I might go 1/2 second faster but getting in to the 11 second standing 1/4 is not easy in a Westfield.

I did 12.36s at 117mph on road tyres (R888s) with something like 30litres of fuel on board and my boot full of tools. I was probably 800kgs. Maybe your PWR isn't as high as you think or mine is higher than I thought   But to be honest I would expect I have over estimated mine and the torque is helping me out. BTW, whilst I was there another Westfield did mid 11s. There were three Westfields there, so not as uncommon as you think.  

[Mark Stanton]

QUOTE

You looked out the Window. Can only theorise at the moment

Ya big southern wuss, call yourself Mr January                 put your thermals on        

[nikpro]

The maths add up on paper. It's in the real world they don't.

Yeah you right, good spot. I have a ccomputational model which I used to calculate this.

Adam,

I'm very wary of posting on this thread as you seem to think I am criticising when I'm not.

I suspect your computerised model does not take into account Load Transfer during acceleration or aerodynamic efficiency.

Can you show me the formula you are using for your calculations?

Probably your biggest obstacle is going to be getting grip from your driven wheels and not the mass of the vehicle. (Your V8 has copious amounts of torque low down in the rev range)

Reducing vehicle weight drastically improves cornering Power but is not as significant in straight line acceleration in a lightweight sports car where you have ample power to start with. (You are probably able to spin driven wheels in first three gears?)

The more Load (weight) you have evenly distributed on your rear tyres during acceleration the more grip you will get from your tyres - making the vehicle lighter could hurt your acceleration due to lack of traction. ( ironically The Fuel, tools and no weight loss by yourself probably helped your time as it's weight located near to the driven wheels!)

You need to add weight to the rear axle by encouraging load transfer to it. Further to this you also will need the car specifically set - up for drag racing. removing a seat from the passenger side will hurt your traction again; the car needs to be as symetrical as possible and the rear tyres weighted evenly as you accelerate otherwise your diff will make available power at the axle lower than the theoretical maximum; add ballast to the passenger side equal to your weight and the seat - you then need to corner weight the car so that the static loads on the rear tyres are as equal as possible.

If you can get more weight onto the tyres you will be able to use more throttle in the lower gears and hence far more acceleration.

The option i would have chosen for better times would have been to swap the rear springs for softer, lower rated springs and increase ride height of the car this will improve grip at the rear axle as it encourages Load transfer rearwards under acceleration.

HTH

Fraser

[adamnreeves]

You looked out the Window. Can only theorise at the moment

Ya big southern wuss, call yourself Mr January                 put your thermals on        

  BTW I am an midlander export  

[adamnreeves]

Fraser,

Thanks for all that info. Makes sense. Regarding weight I did have an incline that it helps getting power down yes but figured that adding ballast is easy but removing weight not so and as I want to do some track days as well, yes I know comprise, make my mind up, etc but I cannot see drag lasting too long as once I get to mid 11s I am happy, famous last words maybe.

Regarding the model I do not know the formula. I am using a product called CarTest2000 which is a simulator. Can only just by the data that is input which is: Engine displacement, Engine location, Turbo etc, Horsepower and where, torque and where, compression ratio, redline, launch speed and method which you can calculate via an optimiser, gear ratios, diff ratio, driving wheels, weight, % weight over wheels, wheelbase, tyre width, circumference, wheel diameter, profile, drag co-efficient, frontal square area, overall height, overall width, ground clearance.

[TIG Brother]

with all this weight loss, have you thought about wheelie bars on the back to stop you now flipping over?  

[Bob Green]

I'm very wary of posting on this thread as you seem to think I am criticising when I'm not.

Frankly, I do not believe Fraser is criticising at all.  I just find his comments very salient in to what Adam is trying to achieve.

And no…………… I do not know or have ever met Frazer.

Just my thoughts.

[Matt Seabrook]

Maybe your PWR isn't as high as you think or mine is higher than I thought  <!--emo&

I have just short of 500 BHP per ton and as Frazer said getting the power down is not easy. At the last sprint I did we have a 1/4 standing start and could not get the power done well until 80mph wheel spin was a major problem. I managed 12.7 I think at 120mph. In 2009 I managed 12.2 at 124mph at the same sprint. My car is set up to go round corners not just blast off in a straight line. May be Santa Pod I would do better is the start line has more grip and I was able to warm the tyres. Tyre warming was not allowed at the sprint. As for knowing the PWR of my car I know its weight and my engine was mapped on a engine dyno and not a rolling road so figures are quit accurate.

Best of luck Adam I hope you achieve your goal but again 11 seconds or better is not easy and I bet there are not many Westfields that could get in to the 11s

Torque per ton may well be lower than yours as I only have a four pot. 350lbft per ton.

[nikpro]

Fraser,

Thanks for all that info. Makes sense. Regarding weight I did have an incline that it helps getting power down yes but figured that adding ballast is easy but removing weight not so and as I want to do some track days as well, yes I know comprise, make my mind up, etc but I cannot see drag lasting too long as once I get to mid 11s I am happy, famous last words maybe.

No Probs Adam,

Removing weight is far more difficult, I would concur.

The weight you remove will be usefull but what i would do is then add this back as ballast into the passenger area so the overall weight of the car is the same as the last time you went but much better distibuted. (race cars are made as light as possible then ballasted to optimise distribution and to meet minimum class weights. This has a bigger advantage than just light weight)

Rear Springs cost £40/pair and are a very easy, reversible change; use the soft springs on the drag strip and then swap for trackday/road use.

Ride height change is free, corner weight £60-£80 a time.

It will always be a compromise, but make the best of it what you can for each discipline because they are so,so different. (dragstrip use needs to optimise longditudinal load transfers where as track use needs better latteral Load transfers).

The other consideration you should consider is camber change in jounce (bump) of the rear wheels. A track car has settings that increase negative camber in jounce to improve cornering power - you need your suspension to have no negative camber gain in jounce on the rear axle(Or static settings of slight positive camber); this ensures the tyre contact patch under acceleration remains at is maximum and stops the tyres rolling onto their inside edges as the rear suspension compresses.

(A well located Live Rear Axle is extremely good at the Drag Strip)

As Matt says; his car is set-up for corners so he really struggles with start line traction in comparison to the cornering force his car can generate.

(All of the above is very cheap to do; it just requires your time and is quite easily reversible, it therefore wont drasically alter the character of your car. This is the real fun of owning a Westfield IMO.)

[andyfiggy2002]

anyone messed around with 4 wheel drive on a westie?  eg. putting 2 motorbike engines side by side with the drive on one facing forwards & the other facing rearwards??

[nikpro]

anyone messed around with 4 wheel drive on a westie?  eg. putting 2 motorbike engines side by side with the drive on one facing forwards & the other facing rearwards??

A well set-up two wheel drive car will always be better than a well set-up four wheel drive car at the drag-Strip.  

[Kevin Wood]

removing a seat from the passenger side will hurt your traction again; the car needs to be as symetrical as possible and the rear tyres weighted evenly as you accelerate otherwise your diff will make available power at the axle lower than the theoretical maximum; add ballast to the passenger side equal to your weight and the seat - you then need to corner weight the car so that the static loads on the rear tyres are as equal as possible.

Sage words. A good few years ago now a few of us were playing with an AP22 and adding a passenger to a V8 Westie decreased its 1/4 mile time by about a second.

Kevin

[Matt Seabrook]

When my car was 20bhp less than it is now I would get in to the 3 second bracket 0-60 two up not so easy with just me in the car.