06/23/09 Having just come back from judging the FSAE student competition (see ETC page) really puts the Atom in perspective. The styling, as I understand it, was a student project by Nick Smart and it's nothing short of brilliant, a genuine milestone in automotive design and one that is certain to inspire many others. The engineering... well, let's just say there's room for improvement. Some of the stuff I saw at FSAE was truly impressive and out of 40-some cars present I didn't see a single regressive linkage on a suspension. I looked. (OK, to be fair I'm aware that some people involved with the Atom wanted to make things right but weren't given the opportunity).
Anyway, back to the latest fix - bellcranks. I got the RP part and tried it out.
It is now a progressive linkage and while my decision to add thrust bearings was a hunch, turns out it was a good thing - there's quite a bit of off-axis force in full compression.
No wonder bellcranks and frames are getting bent. There is nothing I can do about this part of the geometry but I can at least provide more room for component clearance, which I did. The adjusted design still comes in at a minimum of 1.6 factor of safety with 1,600 lb loading on the pushrod. Weight actually drops to 0.6 lbs.
Now to get a few made and get these things installed. I'm also redoing the entire wiring harness to eliminate all the random extra wires. The stock harness is well built, I'll give it that, but the design is a bit baffling and there is no wiring diagram. Brammo did provide a connection list at some point which is better than nothing and lets me figure out what goes where but I guess I'll have to make a diagram from scratch. That'll be a throwback to the electronics days :)
After I get these latest fixes done, Bikini will be for sale as I'll finally feel good enough about the car to let someone else own it. I'll even throw in a 30-day replacement warranty on any parts that I installed - with a brand-new Atom you get none. The asking price is $125K for what as far as I know is the only running V8 Atom in the world. It's quite fast and fun, too - as 1,250 lbs and 400 hp should be :) E-mail me if interested.
07/07/09 Among all the other cleanup I'm also taking the time to straighten out the wiring on the Atom. Since my car doesn't have lights and the ECU is completely different, a lot of unnecessary wiring can be eliminated. Also, what wiring was there never really made sense to me and I wanted to have a wiring diagram. So I basically rebuilt the harness from scratch using some stock wires. Here it is, with some of the discarded stuff being guarded by our shop monster.
I'm still not completely decided on redoing the front uprights. On the one hand I really hate the idea of relying on the stock bearings and drive flanges. If I can actually use the new design on the dp2 and dp3 then it would be worthwhile. One concern I had about making an Atom-compatible unit is the lower balljoint. It is definitely better than using a rodend in bending like the UK cars, but I wasn't sure the retention method of this particular part would work in an alloy upright. In its normal application this balljoint does not carry spring loads although it is the right direction (pull type).
It does have the benefit of being a very compact package so I made a quick CAD model and ran a worst-case test simulation with a 1,200 lb load (about 4g) and no friction.
Turns out it's not a problem at all even in aluminum and as long as I design it without stress risers it should work fine. Mine of course would allow camber adjustment without disturbing the toe setting, unlike stock. So I'll most likely go for it. We'll see how long it takes.
07/21/09 As part of the tidying up that I'm doing prior to selling this beast, the engine side of the wiring harness got redone. Some of the original wiring was done in a bit of a haste and I didn't feel good knowing what state it was in, even though it's not visible. So I completely replaced the ECU connector, replaced all sensor wiring and generally cleaned things up. This harness will also serve as the prototype for the dp1 engine wiring so it was a good exercise in that regard as well.
While all this is happening, the new bellcranks are finally here. I checked them for fit and now they're off to be anodized. Should be done Thursday.
The chassis brace bits also came back from plating and got reinstalled. I made two sets, so the other set is for sale as a kit - the price is $400 for everything (hardware will be included). The install is not for the timid though, since it requires some cutting of the fiberglass tub, drilling the underseat frame and installing some rivnuts. That's why I only made one more. I don't really expect many people to want to do this even though it stiffens the chassis noticeably.
After reinstalling the brace and putting the harness back in, we turned the ignition on and fired the engine up. Started and ran with no issues - good, considering that every single wire on the engine side was either modified or replaced.
We are going to weld up the new suspension pushrods tomorrow, then install the new bellcranks Thursday and we should be good to go.
07/24/09 The bellcranks are now anodized and installed, along with the new pushrods. The pushrods use 1/2" instead of 3/8" rodends and the rodends themselves are premium Aurora units. Bellcranks have roller thrust washers and a progressive linkage geometry.
The car is now back together, ready for the track day on Monday. Should be a good test of all the changes. It's promising to be a scorcher, too - forecast says 97F.
07/28/09 A bit of a trial by fire - well, by sunshine at least. With temps around 102F (39C) our second track event at ORP is certainly a good test of the cooling system. Which worked fine - oil stayed at 210F (100C) and water never went above 200F (95C). One thing that didn't work, as it turns out, is the alternator. The car would start and run fine, then after a few laps just misfire and quit. Attempting to restart wouldn't even turn the engine once. So M and I got to sit in the sun for a while waiting for the session to end (I yelled to the nearest corner worker to keep it running, no point in depriving others of tracktime on my account and I was able to pull well off the track into a bypass). We got to become one with the heat. Here are a couple pictures courtesy of Xqsme Photography (click each for bigger version).
I didn't guess the alternator at first, so after getting a tow back to the paddock at the end of the session I swapped the battery and the car ran just fine. At least for about half-dozen laps giving rides to corner workers and friends. Then it quit, making the nature of the problem quite evident. I didn't have another charged battery to swap in (borrowed the first one from the 900 which was OK with the drained one after a jumpstart from the truck).
Well, another thing to fix. On the plus side, the bellcranks/pushrods worked really well. The new progressive rate makes the suspension compliant over small bumps/irregularities but really limits overall motion, in a controlled way. So the suspension now feels both firm and smooth at the same time. I like it, although I didn't really get to push the car hard handling-wise. Overall balance seemed pretty much unchanged.
The trackday itself went well, with a good turnout despite the heat. On suggestion from Rob we tried running just two rungroups, cars and bikes, alternating 30-minute sessions. For maximum tracktime that's definitely the way to go - even with a couple minor delays we still got 7 sessions for each run group and over 3 hours of tracktime for everyone (or at least those who could last that long!).
Well, I guess the one thing about the trackday that was less than ideal (aside from the heat) is the fact that I essentially only got to run two sessions, one in the Atom and one on the 900, and M didn't get to run at all. Yes, we both could have been out there more but chose to attend to business instead. Perhaps as this becomes more of an established routine we'll be able to relax a bit more and actually participate :) It's interesting how during the first event we were still focused on tracktime and ran a bunch of sessions, whereas this one was more us running the event. I hope we can find the right balance here, afterall that's why we originally decided to do it.
Next event is August 24 and hopefully the weather will have mellowed by then, but not to the point of rain/cold/wind. Signup info is on the Palatov site for those thinking of joining us. In the meantime, the Atom is intent on keeping me busy. Sigh... This one is all my doing at least.
One really cool thing - we rented Wild Winds Ranch upper house again and it's just so nice to be able to relax both before and after the event. At the end of the day we went back, cleaned up, had a barbeque with a small group of friends while the heat calmed down a bit, then took off when we were good and ready. Being the last to leave the ranch we paused for a moment, taking in the absolute quiet. Don't get much of that these days.
08/24/09 Our third trackday at ORP. This time the weather cooperated beautifully. M got to do a couple bike sessions and I was determined to run a bit as well. I started with the Atom - here's a video of a lap. This track ROCKS!
As you can see from the clip, I'm just being conservative (and lazy :), using the power between corners in a point-and-shoot kind of way. The car easily has another 10 seconds in it, if I got some time to get more familiar with it and the track... As it is though, after a couple laps I once again got a mysterious misfire.
Looking at the ECU logs it's crank sensor errors again. Having replaced the crank sensor (with a whole different type even) and the entire wiring harness, my feeling is that the ECU is having issues. This is not entirely un-anticipated and John is now using a later-greater ECU (his newer engines are all working fine but this particular motor is the first customer unit and as such is a bit of a learning experience for both of us). So the question is what to do about this one. For now we are going to try a different crank sensor wheel, with fewer teeth and more thickness to it - John is going to send one to me shortly. We'll see what that does. From the very start Bikini was meant to be a development project and I'm certainly getting all that I bargained for :) I do have to say that it's been absolutely worth every setback and headache. Can't get this kind of education any other way.
Speaking of education, there was another Atom in attendance and one thing we learned by way of experiment is that the Airtab vortex generators I have plastered all over my car actually do work. We put one on the nose of the other car, on the driver's side, and it significantly reduced (almost eliminated) buffeting and helmet lift. No wonder I wasn't getting much of that even at 147 mph at PIR. Cool.
So with the Atom essentially parked (I could keep running but chose to play it conservative) I was left to play with the Ducati... except M was using it. Fortunately I was offered a session on a 1098S (thanks, Dave!!) and wasn't about to turn it down. The bike is great - it's like a somewhat more nimble 748 with twice the power. Definitely more power than I could use in just one session but I still had a lot of fun. The front wheel likes to levitate over crests :)
I'm thinking we should get an 848 in the spring - that would be a more appropriate bike for both M and I and just as gorgeous.
All in all an awesome day, even if it could have gone easier. We are starting to build a community of enthusiasts who are regulars at our events and it's very gratifying. Many new friendships are being formed.
A picture gallery is on the Xqsme site - samples are up now and more pictures are coming in the next couple of days.
09/04/09 It now feels strange to do someone else's trackday - a Lotus Club event in this case. I did instruct at a BMW day earlier in the week but didn't run. The Lotus day is always fun because of all the racecars that show up and today was no exceptions. Below is the only car I actually took pictures of - a UOP CanAm Shadow. The owner is part of the bi-weekly 'engineer's lunch' here in Portland, a small informal gathering of gearheads, car nuts and car designers/builders. Yes, there are a few in town.
I've posted photos of this car before but this is the first time I got to see it fully out in the open, so what's a few more pix. It is ridiculously wide as are its tires. Funny part is, the Atom runs roughly comparable lap times.
Speaking of the Atom, it is still having brain issues. Runs great for about 5 laps then starts misfiring. ECU data log says crank sensor errors (which could also be cam sensor errors). I've replaced the timing wheel and after the first session I replaced the crank sensor too. Same result. OK, well, we know what this ISN'T caused by. Cam sesor is next. After that will have to bite the bullet and swap the ECU.
On the plus side, the oil problem is now officially solved and it's gratifying to see the car sitting there with not a drop under it. Some may recall how long that took to address. So the current problem will too be overcome. The annoying part is that the car runs fine for a while on the track and on the street the problem doesn't show up at all. So it's a bit hard to diagnose. Well, all this is character-building. I do have to say that while it's running well, the power is just awesome. I totally love this motor and can't wait for the first drive of the dp1 with the 500hp version. I did manage more than a dozen good laps and it was fun.
Also, to test my suspension mods I purposely hopped a couple curbs - enough to see plenty of daylight under the front wheels which are in plain view of the driver. No issues, nothing bent and it didn't even feel harsh or like much of an event at all really. Just a bump. At least some things are working well.
09/19/09 The new ECU showed up a couple of days ago (a DTA S80PRO, a more modern and capable version of the old one). It is definitely a nicer unit and everything from features to the connectors is better. Still, I had put so much work into getting the old connector and harness wired up that it was a bit painful to just cut it. Had to be done though.
The new setup uses two connectors instead of one, with sensors being completely separated from injector/coil drivers. It makes sense and the physical connectors are a vast improvement over the previous version. So, after nearly a full day of cutting, crimping and soldering, the new harness is ready and installed.
One of the many benefits of the new ECU is better diagnostic capability, it actually gives you an oscilloscope-like trace of the cam and crank sensors. Which helped solve several puzzles when the engine refused to start at first. It was easy to trace the issue back to the cam sensor (which I had replaced as part of the ECU upgrade) and after some tweaking I got the thing to fire up and run. The map from the old unit transferred right over with minimal adjustments so the Atom seems to be ready for next weekend. Hopefully this finally fixes it. If not, at least I would have better insight into what's going on. Overall the car is vastly better now than when it first ran. And I've learned a LOT.
09/29/09 FINALLY! The car works and works very well. Karl did the driving (some 200 miles on track) while I was dealing with the challenges of the event and quickly proved my earlier assertion that Bikini had at least another 10 seconds in it by turning a 1:51.8 lap (versus 2:03-ish best that I could manage in the few laps that the car actually ran previously). It is a good illustration of the engine's flexibility since Karl did the entire track in third gear! He thinks there's another 5 seconds or so to be had but neither of us was willing to try it, what with the car being for sale and all. Below, the black trace is Karl's and red one is mine.
To say that Karl was impressed is an understatement. I think the direct quote was something like "This is absolutely the ULTIMATE track car among all I've ever driven! The engine is amazing!" (the next sentence was "Can't wait to drive the dp1!").. Coming from him that's saying a lot. An interesting consequence of having a car this fast is that even with the 2.5 mile track and very limited traffic he never actually got a clean lap - he was always passing someone and lapped some people several times in a session. Unfortunately the event was too hectic for us and we just forgot to mount the camera. I'm kicking myself now but so it goes. Working as well as it did, Bikini has also served its purpose as a demo vehicle of the Hartley engine since Karl has now decided to buy a dp1 :)
With all the issues finally sorted Bikini is ready for its eventual next owner - whoever he or she may be, they won't be disappointed.