Monday, April 13, 2009
Oh My God. I love Thunderhill. I mean, deep spiritual connection with a kindred spirit. Whomever is responsible for it's layout, I want to buy you a beer. Now I see what everyone rave about. Some say Infineon is better but I think driving wise they're equally challenging, Thunderhill with more gut-check high speed turns and is leagues safer than Infineon. So in my book, no comparison. Thunderhill is the best overall driver's track in California.
So anyway, you all want to read about the car and update have been scant. Well I've been missing a lot of sleep, driving way too much, working to many hours and still really don't have time to make an entry, but I feel guilty so here's the latest..
Rattle canned the cage in flat black after install. First time at the track and it works! No reflections on the windshield whatsoever. Great video too. The Momo seats while being quite snug, also keep me from splaying my gangly legs apart to clear the steering column. So my knees were hitting the key among other things. Stripped everything down to the bare column, dug the little plastic ignition switch out from behind the heavy die cast key cylinder and zip tied it to the dash bar. The key was now useless so I fashioned a "key" out of a little stamped steel chrome flat wrench, ground it down and used some fine stainless cable to hold it in the socket. Works like a charm and shaved about 4 lbs. Bets of all I have plenty of knee room and was able to move the wheel towards teh windshield with my adjustable steering hub spacer. The company that makes my forged lugs also makes these things. Looks like a coilover adjuster. Very handy.
Gauges don't work, except the fuel gauge which does work. Something in the harness I no doubt screwed up when removing the dash. have to get in there with a VOM when I get a chance. Be nice to have a tach.
The Tubular subframe was a piece of cake to put in. I'm in love with it. So much room to work around and really easy to attach things to like undertrays, oil cooler hoses, remote reservoirs for the dampers, what have you. Bunches easier to do trans/clutch swaps now too.
Which brings me to the 7.25" twin plate clutch we're developing. The engineers gave me a set of organic discs to test and the experimental bonding adhesive didn't work. So out it came and the sintered ceramic-metallic discs went it. The ceramic discs weigh about 1.1lbs more the pair than the organics. Boo. Anyway, the clutch is just fantastic. Despite having no mass and be able to speed shift it now, I can still creep it up into the enclosed trailer at a snails pace. Magic. The organics for the briefe period I had them in were even easier to modulate. In teh video's attached, you can hear how quickly it revs now. Like some kind of built race motor and it's just a junkyard bottom end with a little (very little) head work.
When we took it to Laguna Seca for the Miata 20th anniversary celebration, I didn't get the suspension assembled right so I wasn't able to run. I did do about 10 laps kinda limping around while trying to diagnose the problem and manage about a 1:43 anyway though.
Next outing for the new build was Streets Of Willow (CW) on Friday, April 10th. First time I realy got a chance to beat on the car for a full session and see how the new XIDA's handle the bumps at SOW. It's probably the best track for suspension testing beside Buttonwillow because its so bumpy. The short version of the verdict: smooth! Iwas expecting a harder, choppier ride but it was a bunch smoother than the revalved Flex's and Mono Flex's I'm used to. Kind of undramatic actually. No fuss, no extra motion, just rocketing over stuff that would have any other Miata I've ever driven bouncing, skittereing or needing steering corrections. I played around with damper settings but it felt good no matter what I did. I tried to make it pump upest the car by cranking in way too much compression damping but it was still fast, just harder to drive smoothly. Turn the comp adjusters back a few clicks and it was faster, and easier to drive. On smoother track like Thunderhill and Laguna Seca, one could definitely take advantage of that stiffer range without penalty.
Next on the list of thinsg to evaluate was the OS Giken differential. I wsih I could say that I could tell it was working but much like the XIDA's, it was really transparent. No sudden locking, no noise, no jerkiness no nothing. You turn in off throttle and the car rotates just like Torsen. Trail brake and you get much less, or no inside rear locking. Stomp the throttle on a slow, bumpy or off camber turn and you get no wheel spin. That's not a little wheel spin. No wheelspin. Anywhere. The main thing I noticed is that I could get on the power way, way earlier than I copuld with the Torsen I ran for most of last year or the 140in/lb preloaded FC RX7 diff I ran for the last 8 months. It's almost like having a lot less power. I mean, you can jump on the throttle in places that would have just spat you sideways with the torsen or RX7 diff. Now it's just feed power in , the rear squats down without changing the attitude of the car and it just rails around the turn.
Pulled the 15/16?" FM front bar I had been using and fitted a 1.125" Racing Beat (94-97 thinwall). With that and teh giant APR GT-II twin element wing, I had a turn in push all day. A bit tight coming off but managaeable. Anyway, set the new absolute SOW CW lap record for Miatas, 1:24.128
Left SOW early. Just as I was pulling out, a 997 pulled into the pits with coolant steam pourig out of the engine bay. Little did I know that about 20 seconds later 4 separate cars went off the chicane at high speed after hitting the coolant spill. One fellow totaling his beautiful S2000 and banging himself up pretty bad. No one was seriously injured, thank goodness.
I woked through the night the Thursday before SOW to prep the car so I was operating on virtually no sleep. Rolled out about 2:00and headed north on the long ass drive to Thunderhill. It's like, in another country, I swear. Had to stop for three power naps. Got in a midnight. Blessed sleep. Going to bed thinking, "this track better be good".
So Sonny, Andrew, Nick and myself all had a blast tearing around Thunderhill on Saturday. I knew I needed to free up the car to get it to go fast in the high speed stuff so I put the smaler FM front sway bar back on. In my haste to get it back together and on the track, I forgot to reset the toe after adding some 3/16"rack shims (bumpsteer). So I had like 3/4" toe out or something horrific. Came in after one session scratching my head "why is the steering so rubbery, why are the insides of both front tires so freakin hot and why is it still pushing like mad?". So I'm standing there in the pits staring at it when I notice the right front is steering of towards Nevada while the steering wheel and left front are headed to Hawaii. This might be the problem. doh.
Fixed that, removed the second element of the wing, went back out and magic. It rotates! Pretty much left it like that for the rest of the day, just fine tuning pressures and compression settings on the dampers. Late in the day while I was stepping up to proper entry speed for T9, I locked up the rears and went off. No harm done, rolled back to the hot pit, took one full turn of rear brake out of the proportioning valve and that did the trick.
Well, that's it for now. It's 12:17 am. Dammit. Worked past midnight again..