Friday we headed back out to HPR to do some more testing on the car to see if it was all set for Seattle or not. As it turns out, not, but there are some good positives.
On the upside, the problematic brake line didn’t leak at all. We did see some wetness on the driver’s side of the car after the first session, and thought perhaps it was leaking again (cursing ensued), but it turned out to be some migratory oil from the oil temp sensor near the water pump.
The new wing support cables worked quite well, though I had to snug one back up after the first session. They actually look almost factory!
Big downer from the day was a high RPM misfire/hesitation that manifested as I started pushing the car harder, and steadily worsened throughout the day. I tried replacing the
throttle bodies, removing the FlatShifter, and even rewiring the ignition/fuel pump switch to a spare to see if that would solve the issue. On the last session, I noticed that the
dash also shut off when the engine stuttered. Unfortunately, I didn’t have any time left to try anything else, but that definitely points to something far upstream, like a bad
master switch or perhaps even a bad battery.
Among the frustration, there were lots of good points. First and foremost, the car doesn’t seem to have any big problems. It’s going where it’s pointed mostly, the balance seems OK. Nothing is coming loose, the chain is staying put, and the shifting is good. FlatShifter is working pretty well on downshifts and flawlessly on upshifts. All the leaks are fixed up and the radio seems to be at least OK to start with. Lots of good so far, just one more issue to sort out, and then it’s time to do some debugging.
Shocks and Motion Ratios
One of the noteable downers on the car is the shock damping – it is HUGELY stiff. It feels even more sensitive to bumps than the DSR did before sending the shocks off to Chris Billings for revalving. As such, I’ve gone and measured the motion ratios as well as I can on the car (which isn’t all that well). Both seem to have a decreasing curve – i.e. the further into bump you go, the lower the motion ratio gets. Near as I could measure, they were both around 0.94 at the ride heights I have. I think it starts closer to .98 or so in the rear, and the front might be a bit lower, perhaps .90-.92 or so. Note that I’m using the ratio as shock:wheel travel, so in my measurements, the shock is traveling .94 of an inch for every 1″ of spring travel.
My unsprung weight measurements were 39.0# front, and 49.4# rear, very similar to the DSR.
After getting the car back home, I had just a bit of a cleanup day – reinstalling the switches in their normal spots after having stolen the rain light switch as an ignition switch briefly,
and drilling the spare throttle body set for the FlatShifter blipper.
One installation note: the fill tube on the side-fill cell on the F1000 can make R&R of the center body section extremely difficult. However, the metal fill neck is quite long, so one thing you can do is significantly shorten the plastic fill tube, to reduce how much this interferes with the body as you try to reinstall it, and get the metal fill neck back into the fill tube.