0-60 Time

In the absence of a rolling road it is nice to see if the performance of the car is dwindling in horses in any way.

There is an excellent on line 0-60 mph calculator http://www.060calculator.com/

For the J15 this gave 4.31s for 627kg and 155bhp. The weight was taken from the recent corner weight measurement and the bhp was taken at Sitech racing last year http://sylvabuild.blogspot.co.uk/2013/08/ecu-re-mapping.html

I set up a track on Race Chrono, using a safe bit of road where the terminal speed was less important and 60mph was obtainable in relative safety. You can see that the example gave a result of 4.8s which is about 0.5s pesimistic. However if you take into account that the test track was up a gradient then an error of 0.5s is not bad correlation. Also 0.3s is being lost in gear change time, something I may or may not be able to do something about, it is always going to be slower than a paddle shift in the Megabusa.

I have measured my wife's Mondaeo, Westfield Megabusa and a Westfield Zetec (*) and all gave results that were within 0.5s of prediction (* butterfly fault).


Contents
http://sylvabuild.blogspot.co.uk/2012/01/sylva-j15-is-kit-car-designed-by-jeremy.html

Corner weights

 I have been concerned about the corner weights since a) running into the Kombi and b) Breaking a NS upper wishbone (on a speed bump I suspect). I have just done the Westfield Megabusa track car so it is now time for the J15.  There is a very good on line spread sheet and explanation of how to set up your car at: https://robrobinette.com/corner_weight_calc.htm

There is also a very good Excel spread sheet by Nick Warinner of ntw@360racing.com that I copied and modified to add the cross weight calculation information recommended in the above advisory site.

Cross weight = (Right Front + Left Rear)/Total weight.

I also purchased a set of Proform Bluetooth corner weight measuring pads from ebay tegiwaimports these are a budget product but works well and is easy to use.

Here are the results, you will have to open the image by double clicking it.
In summary I did the following.
1) Ensure the tyres are all the same pressure
2) The suspension height front and back are correct. In my case the lower front wishbones are horizontal and the front to back was 20mm
3) Adjust all the spring lengths FL = FR and RL = RR as a good starting point.

Before adjustment

After adjustment no driver

With driver

In summary I can see no issues with the suspension, the initial setup was done with a ruler and gives acceptable results only 1% out. The key issue is confidence the car is right.

Like the Busa I cannot see the advantage in my car of biasing it to handle with the driver only as it only makes a 0.3% difference. It means the handling is optimal with a passenger also depending on weight.

Contents
http://sylvabuild.blogspot.co.uk/2012/01/sylva-j15-is-kit-car-designed-by-jeremy.html