JPSC Forum

On the recent Debden sprint Chris Hussey in his (and David's) Busa engined Striker did a 63.x sec run with me trailing 3.5 secs behind. The Striker is running slicks and has a weight advantage which would explain the difference until you look at the datalogs. Chris has kindly sent his best run across in the same format as my best run and this is the comparison.....

Map of the circuit in 3 sectors


Timings for both runs (note this slightly out as I have the finish in slightly the wrong place but close enough for this exercise)



The the data itself (sorry for the large size)



The data is long accel, lateral accel & speed, all against time.
As you can see the Striker is absolutely killing the CEC Phoenix on acceleration, to the tune of 2 secs in the first sector alone. The peak speed is also some 10 mph higher into the first right hander. Not much difference in lateral G force even though the Striker is on slicks and Chris is able to brake slightly harder. The only place I make any time is on the fast sweeping corners (both the right hander and the returning left hander the Phoenix is up by 8-10mph) which suggests Chris could have gone a far bit faster if the corner speed matched mine. You can also see if you look closely at the long accel how much quicker his gearchange is....

this is the video to remind you what my run looked like

http://www.youtube.com/watch?v=7Ayheh1eZ4U

I have started looking for a ZZR1400 engine

That is some good info but WOW that is a drastic move to a bike engine

The BEC route is something to consider although I am more likely to upgrade the current engine. It is interesting (to me at least) to see the differences in the runs.

This shows the differences slightly better as it is speed over distance. The circles are the various sector points. The two graphs are slightly offset as the two GPS receivers are not calibrated the same way.

Jeff , looking at your photo of the course with the overlaid marker and sectors , the course looks identical to the one I remember from 2005 which is strange ---- I'm sure you and David have mentioned '' the new course '' at Debden in previous posts

They reverted to the old course for this run. I'll load a map of the other course if you are interested.

jeffw wrote:The only place I make any time is on the fast sweeping corners (both the right hander and the returning left hander the Phoenix is up by 8-10mph) which suggests Chris could have gone a far bit faster if the corner speed matched mine.

Not that surprised, Jeff. We spent all our time last winter getting the new drive-train in, so the suspension is still the same as the (relatively firm) set-up we had when the car (then CEC) weighed in at 545kg. Now it's 75kg lighter. It's great on smooth circuits, but difficult to keep on the ground on bumpy airfields. Something to think about this winter..............

jeffw wrote:You can also see if you look closely at the long accel how much quicker his gearchange is....

Bike sequential with "flat-shift", so should be reasonably good. Interestingly though, the manual (clutchless) upshifts with the 5-speed H-pattern dog-box we were using last year were almost imperceptible on the speed trace. Again, perhaps scope for some winter optimisation of the system.

jeffw wrote:I have started looking for a ZZR1400 engine

Can't see you wanting to make a large hole in that very pretty bonnet -- but, if you did ..... this is what a 1400cc bike engine can do ...



... and yes, there's more to come if we can find a (safe) way to raise the soft cut a bit!

the manual (clutchless) upshifts with the 5-speed H-pattern dog-box we were using last year were almost imperceptible on the speed trace

How was the dogbox? it is something i have been thinking about getting but will see how my type 9 fairs this new year? can you change gear on full throttle or do you need to ease of the power as if you are using the clutch?

the graphs may not be calibrated but they are so close to each other and interesting to see where you lost the 3 seconds

Simon

The area under a speed/distance graph is indicative of time. Where the graphs diverge, time is gained or lost.

HTH

dopdog wrote:

the manual (clutchless) upshifts with the 5-speed H-pattern dog-box we were using last year were almost imperceptible on the speed trace

How was the dogbox? it is something i have been thinking about getting but will see how my type 9 fairs this new year? can you change gear on full throttle or do you need to ease of the power as if you are using the clutch?

Up-changes require only a very tiny lift, practice makes almost instinctive. Down-changes require (at least in my experience) both clutch and a little blip to avoid wearing the dogs. Both benefit from positivity bordering on brutality -- which is not natural for those used to synchro boxes.

Another issue is that (at least for our box, TranX SL72) the gate is very narrow. It becomes very important when changing up very fast to make sure you hit fifth rather than third

But, once you've tried one in competition I doubt you'd ever want to go back to synchro. Bit clunky for road use though.

HTH