10/13/07 After quite a bit of tinkering with the maps and the electrical system (things like getting the ECU to turn on the radiator fan, etc.) I took advantage of a rare sunny day today for a quick putt-putt around the neighborhood. While I'm still sticking to the side streets I did try a mild acceleration run on a clear, steep uphill section. Second gear, roll-on maybe 2/3 throttle, limit to 5500 rpm. YEAH. This thing rocks. M was laughing out loud. Then I told her that I wasn't even pushing hard and the responce was "F*CK!". He he :) I'm really looking forward to driving this beast regularly. Need to take care of quite a few more items before that can happen but progress is being made. Of course the dp1 with this engine is going to be unreal.
No video or pictures today but we'll see if the weather holds up tomorrow....
The weather in fact cooperated so I enlisted M as the camera girl in my driveway and drove by a couple of times just to try and give an idea of what the car sounds like from the outside. Obviously I can't open it up anywhere near potential in this setting, for a lot of reasons, but one can kind of get a feel for the sound in this short video (6M). Bikini is definitely coming along.
After a few video passes M drove it a bit around the neighborhood drawing puzzled looks from the residents and passers-by. Predictably nobody seems to know quite what to make of it. A girl in wrap-around sunglasses behind the wheel just confuses them more. The V8 is very tractable even at low speeds. Nice. I definitely need to work on the systems some more but at least the mapping is starting to come in little by little.
12/29/07 With a lot of business stuff and client projects, it's been a while since I've done any hands-on work. So before the year is over I figured I'd do some. OK, it was also motivated by the need to get Bikini parts out of the livingroom - all part of some major changes happening in my life. All of it good :)
Anyway, I spent the afternoon in the garage installing the airbox/filter, the overflow reservoir and a few miscellaneous bits. Bikini is looking more finished now.
Feels good to fabricate things, actually. Lately I've had others do it for me and while it's an effective way to get things done, sometimes it's rewarding to put a file to the metal.
On January 1st the Brammo law goes into effect, which should allow me to finally register this beast (hopefully). The actual text is here for those interested. It is curious how specific the description is. The story is long and twisted but basically it's an end run around a self-important bureaucrat high up at the DMV who had taken it upon herself to disallow Atom registration. Took about a year to reverse this unwarranted discrimination against a company providing Oregon jobs and tax revenue. However, in an odd twist, what might be an unintended consequence is that now there's a legislated incentive to create cars that look very much like the Atom... :) Hmmm.
In other news, dpcars is now separately incorporated and will eventually be getting a car dealer license. For now our main product is Ducati Sport Classic license plate brackets, a business that is doing surprisingly well. In the coming weeks you'll see some changes to the site to reflect all this. And more.
01/26/08 The weather is very non-Atom-friendly these days but I decided to do some more work anyway. Got the oil cooler fixed by a radiator shop. It took two weeks and looks ugly but hopefully it'll hold. So I put the thing back in and ran the engine for a bit. Scavenge pressure is a little higher than I'd like, the cooler has about an 6-8 psi drop across it. At least when the oil is cold. John and I have been talking about gearing the pump down some because there's more than enough main pressure and getting it to turn slower would free up some more horsepower too. So hopefully I'll be getting a new sprocket before too long. Another thing I'm waiting for is the registration from the DMV. It shouldn't be an issue but then I've said that a year ago too... We'll see. Plenty going on in the meantime. I almost felt guilty taking the time to tinker with Bikini right now but multitasking is something I do pretty well so no harm done :)
04/05/08 (UDPATED 04/06) There are several reasons I haven't updated the Bikini page in a while. The most important is that I've been busy with other priorities lately. But despite that some progress has been made.
The car now has a legitimate and legal SP (special interest) license plate after more than a year of trials and tribulations. I've been tinkering with oil pump gearing - John had been pretty conservative in the initial setup and as a result I had 50 psi oil pressure at idle, spiking to over 100 psi at times and that's without even redlining it. So we tried a couple different ratios and I now have 35 psi idle with hot oil. Haven't revved it yet, we'll see what happens when I do. The weather hasn't really been Atom-friendly (a recurring excuse, I know, but it's the fact of life - it's just not fun to drive this thing in the rain or when it's really cold, let alone snowing, and winter gravel on the road ends up in your face) but summer is coming so that excuse is going away soon. Hopefully. Snow like we had in the last week of March is not what I'm wanting to see here.
Another issue is that a while back Brammo sent me a nice letter saying that the rodends used in the suspension pushrods are too weak and have broken on several customer cars, so I really need to replace them. They said they're out of stock but nicely offered me $180 'store credit' if I went and bought them myself. Uhm, how about buying them and shipping them to me instead? Nope, I guess that isn't an option. And of course the whole Atom business has now been sold to a Canadian company (but apparently will still be built in the States?) so I don't even know who to talk to anymore. Whatever, it's just $180 so I went ahead and ordered the better rodends. They are still not enough in my book, being 3/8" parts where the 30% lighter dp1 uses 1/2" premium pieces for the same function. But I'm not going to redesign the suspension, just have to make the best of it. The new parts are definitely fine for ultimate load rating (as were the old ones, actually, albeit with less margin) - it's the fatigue life that's in question and these parts see thousands of complete load-reversal cycles per mile.
UPDATE: I posted this Saturday evening and Sunday morning there was an email from David Goadby, the president of TMI AutoTech which is the company that took over the production of the Atom in the US. Turns out they are fully supporting the cars and will be sending out replacement rodends at no cost shortly. Cool, that's nice to see.
Yet another bit is that after a few heat cycles the exhaust is 'relaxing' and the pipe is now too close to the spring perch on left rear shock. The solution is to get a shorter spring which would move the prech out of the way of the pipe. There are plenty of choices in 2.25" ID but very few (none, actually) in the 60mm/2.5" ID that is stock. Fortunately the shocks will take a 2.25" spring if I remove the spacers and so I ordered a couple of shorter, narrower springs. The smaller OD might even clear the engine mount bolt on the other side and actually let me run the rear shocks inverted but I won't know until I get the parts in and test fit them. I've also bumped up the rear rate while I'm at it and will install stiffer fronts when I take things apart to swap the rodends. The new rates will be 40/60 N/mm (230/350 lbf/in). Some may recall that earlier I had put the car on corner scales:
So the new wheel rates (equal to spring rates at 1:1 motion ratio) will pretty much match corner weights which is a good rule-of-thumb for a non-downforce track car.
It would be nice to have all the tinkering done and actually put some miles on the thing. On the 21st is a Lotus/Motocorsa trackday and it may be interesting to compare Kermit and Bikini there. Would definitely be a perfect venue for it but I don't know if I'll get it all done and get the break-in taken care of on both cars by then. If not, there are plenty more trackdays this year.
04/08/08 Got the new springs today, popped them in. It looks like inverted operation for the shocks might be feasible, although the 5" springs I chose might be too short for the travel. I may consider 6" ones later as a compromise, we'll see. Thankfully they are inexpensive. The weather has been really spotty lately but for a brief moment it looked like clear sky, sunshine and relatively dry roads so I decided to take Bikini for its debut run as a registered car. The law states that the car should have "the equipment supplied by manufacturer". Since mine came with no lights, I'm technically legal without them during the day. Hand signals are easy and it does have a brake light.
The route was my standard one consisting of my favorite twisty road. Damn, this thing is very entertaining! The V8 is perfectly tractable and the way it moves the car is totally effortless and makes it obvious how much is in reserve. But it's happy to run around at under 5K RPM too. Twinplate clutch has good feel, the shifter works well (longitudinal throw could be shortened but I have other priorities for now). Regular sunglasses, even wrap-around kind, are totally inadequate at anything over 30 mph though. Need to start wearing ski goggles or a helmet. Made it home just before rain started to pour again.
I need to look at the ECU data log to see what water temps are like, there may be a need for more cooling since the fan was on when I pulled into the garage and it's a fairly cool day. But I do have the fan point set pretty low. Anyway, lots to tinker with still but I should be venturing out in this critter more often now. At some point we'll take it and the Exige on a run and swap back and forth a couple times. All in the name of testing, of course! :)
04/12/08 A gorgeous day today - Bikini weather. Longest drive yet, just under 40 miles vast majority of it on twisty two-lanes that sneak up and down to Skyline. The roads are mostly gravel-free although some are a bit bumpy. I'm now able to pay a bit more attention to the car itself so here are some early impressions:
I totally love the engine. Pulls cleanly from 2K rpm, idles evenly, sounds great... And the couple times I punched it, only 3/4 way or so and staying under 6K rpm - WOW. The intake sound turns sharp and aggressive, exhaust screams, and the thrust is very gratifying (it keeps building with revs, just like a sportbike, so there's much more to come after break-in). A well-mannered monster. We were behind a station wagon for a while with two kids in the back. The kids waved and then started taking pictures with their cellphones. A short straight came up, two blips of the throttle short-shifting through a couple gears and the station wagon is far behind. Wonder what conversation was taking place inside.
On the subject of gears, the gearshift works very well though it helps to be gentle with it. Later in the day I drove the Exige to the coast (see its page) and that shifter I do not like as much. Score one for Bikini.
Wore ski goggles this time and it's much better than with sunglasses. Was glad, too, having watched several rocks bounce off the double lens. M got a rock hit in the middle of her forehead. Didn't draw blood but she felt it. This car truly IS a four-wheel motorcycle and as such a full-face helmet is really the way to go. I'll try that next. Also, the rawness of the experience wears on you after a while (like 20 minutes) and I think a helmet would help that a lot.
The car is quite skittish over the bumps. The Exige just glides over the same roads by comparison, communicating every bump as an FYI but shrugging it off as a non-event. The Atom is not nearly as non-chalant about uneven pavement, something that was obvious not only to the driver but also to the passenger. This may be at least in part due to my spring changes and the fact that the shocks have only been adjusted roughly to match, but every Atom I've driven had felt like this and I remember it from my very first test drive in Ashland way back when. It almost feels like there's too much unsprung weight for what is a very light car. Now this is only a gut feel and not confirmed by anything, so take it as a descriptive statement rather than a factual one. And I do have pretty light wheel/tire setup on there, if memory serves about 31 lbs combined. Hmmm...
Anyway, after some 40 miles in 45 minutes (on roads where most corners are marked 25) we're back at the house to grab Kermit for a sprint to the coast, normally about 90 miles away but we'll be taking the long way. Frankly, it's not a trip I'd contemplate in the Atom (may change my mind after I try it with a helmet on, but in 'civilian' gear the comment stands). See the Exige page for the rest of the story.