build diary

November 21, 2005:
The books are starting to ship out, although I haven't heard from anyone yet who's received one.
Am I a little nervous about its reception? Of course!

I've been thinking more and more about what to do with respect to the suspension. I was recently provided with a set of measurements for the Miata suspension, front and rear. Should I just stick them on? I can't, the nose isn't wide enough. I will probably model them in a 3D program and see if I can get the same behaviour though. Rumour has it the roll center is extremely well controlled. I'm also going to model my current suspensions and see what the camber curves look like and if it does have a good ride height for roll center control. A call from the owner of the GRM Locost indicates that he is (probably) running on the front bumpstops. Combined with the lower CG thanks to the lower ride height, this might explain why his car seems to roll so much less. And sometimes I just wonder if I'm being too much of a perfectionist (whiner?) and I should just stick some stiffer springs and sway bars on the car and drive it. It's quite possible that all I really, really need is a good alignment done on a rack instead of at home.

I was thinking more about the handling of the car today while driving in to work in a Miata. I realised that while I'm giving the impression that it's a real handful to drive, it's actually very friendly. There aren't many cars that I'll purposely pitch into a big slide, certainly not with the sort of cornering speed and traction generated by the Seven. I want the car to be world-class and corner as fast as it possibly can. It should be superlative, not just impressive.
entry 1073

November 22, 2005:
Hey, a real update with real information in it!

My new muffler arrived today. It's monstrous. 6" in diameter and 27" long. It's a big change from the 3.5" resonator I have now. I suspect it will muffle the Seven almost completely. That's not such a bad thing, it's a vocal little beast and while I'll probably miss the flames and racket, this will let me hit full throttle without wincing. The resonator didn't really work well for actual muffling. I'll get used to this new monster eventually. Hopefully. Maybe I'll have to exchange it for a 4 x 22" one or something.

While reading various Carroll Smith books and Miata technical manuals (how sad is that?) I realised that I have a potential area of improvement. My shocks came with little hard bumpstops. Nothing fancy, just something to take the worst shock out of a bottoming. The original Miata came with a similar setup with a little more attention paid to the shape. In 1999, Mazda introduced a much softer bumpstop that looks remarkably like the ones described by Smith. They're made of urethane and according to Mazda, "Because urethane has damping force, the bump stopper reduces the skipping sensation experienced during strong laternal gravitational force on rough road surfaces and improves cornering". Hmm, I expect the engineer that wrote that was Japanese. But I have a set here off a Miata and I'll give them a try. Bill Ritzel, a Miata enthusiast, sent me some pictures of a clever plug wire cover he made. I think that will be a nice addition to the Seven and keep the wires from scuffing on the hood. Watch this space!
entry 1074

November 23, 2005:
Miata bump stops.
If I remember correctly, the yellow one is from a 1999 model and the red is from a 2001. The yellow is noticeably stiffer. The profile of the red one is designed to give an intial soft damping that firms up. It will be interesting to see what these do.
entry 1075
The monster muffler.
That book is a typical 8.5 x 11" size. Have I overcompensated for my, umm, lack of muffling?
entry 1076

November 27, 2005:
I've decided that muffler will have to go.
The next size down should be just about perfect. I also decided today was the day to get the hood done. It's been very frustrating work though. I annealed the aluminum but it's not keen to bend. This forced me back to my wrestling technique used on the first hood. I'm not convinced it's turning out as well as that one did, perhaps it's a different alloy. There's a small imperfection in the bend (a medium shallow dent) that will be fairly obvious when light reflects off the hood. I'll have to see if I can tease it out somehow. Doing this job again was not part of the plan and I'm not enjoying it one bit. I have yet to find a picture of a hot rod with the louvres on backwards as they are on my original hood so the mistake was not just a matter of miscommunication.

I took some measurements of the suspension pickups today. I just have to measure the front uprights and I'll be able to model the suspension and see how well it's working. I could do this with the existing Excel sheet from the US Locost group but I'd rather design my own little suspension analysis program. Hey, I'm in this to learn.

Skip Cannon is a Miata-owning friend of mine who's caught the Seven bug after driving a Caterham SV at the Aspen track day a few weeks back. He wants to run a Miata motor in it though. He's not a web junkie like me but he does have a bit of a site up on the project.
entry 1077

November 28, 2005:
The big muffler sitting under the current exhaust.
Yup, it's too big. The exhaust system would sit too far away from the body for my taste.
entry 1078
The new hood underway compared to the original.
The black mess is some protective plastic that was intended to keep me from scratching the aluminum. I had to peel it back in order to anneal the metal.
entry 1079

November 30, 2005:
No work on the car recently because I've been preparing for another trip to California.
This is a short one though, just a long weekend. I'm going to be part of the pit crew for a couple of 2006 MX5 race cars in a 25-hour race. This should be interesting stuff. Caterham did very well in this race a couple of years ago but unfortunately they won't be there this year. I'll see if I pick up any good tips looking at this car.

It's time to set some goals for the Seven, though. Let's see, I'll get the suspension modelled by the end of the year and decide what path to take there. I'll also have the hood finished along with a new exhaust. There, a target! I'm not working at the feverish pace I was when I was coming to the finish of the initial build, am I?
entry 1080

December 6, 2005:
Back from the races!
Very little Seven-related activity although being that close to that many race cars managed to get me all itchy for more track time myself. The cars were, for the most part, nicely prepared by AWR. The biggest problem was that we had in setup was a lack of shock damping. The cars were running on stock shocks because they were so new and nothing else was available. We also had two cars with identical setups that worked differently - one oversteered enthusiastically, the other would not do anything but push. We worked away at finding solutions and it was very interesting watching the experienced racers do what they could to get the cars to work. They did get better but were never exceptional. Drivers from other teams were commenting on how the little guys bounced around. Unfortunately, we had a few problems over the course of the race (fulfilling our role as a development race) and were not in the hunt for a win by the time dawn rolled around. Shortly after, one of our cars also rolled around on the track a bit and became a good candidate for a Locost. The other droned across the line stuck in either 5th or 6th gear.

December 7, 2005:
Oooh, look at the pretty little Miata race car.
25 hours later, it was a Locost donor due to a small argument with another car.
entry 1082
Racing started at 11 am.
This is dawn the next morning.
entry 1083
A peek at the differential for the new MX5.
It looks like it should be a good option for a Seven. I didn't weigh it but it seemed quite light. And yes, it's smoking.
entry 1084

December 9, 2005:
For those who want a few more pictures from the races, there are some on the Flyin' Miata site.
This is a diary about the Seven, so I'm not going to digress too far.

The exhaust system is not going to be finished before the end of the year. I haven't sent the huge muffler back to Summit Racing yet and I have only about 12 days before I leave for the holidays. I will attempt to finish the hood though. I'm also learning SolidWorks (an extremely cool 3D prototyping program) to play with suspension bits.

Also on the suspension - this photo was referenced on the LocostUSA builder's forum. Those rockers are apparently stock motorcycle parts. I hadn't considered that approach - motorcycles tend to show up in junkyards with regularity so if I can identify a good part, I should be able to buy it fairly cheap. The design of the rocker is the difficult part of the inboard suspension, I'll let the highly-paid motorcycle engineers sort that out for me!
entry 1085

December 14, 2005:
At some point I'm going to have to wander back out to the garage and at least finish the hood.
Sigh.

I've written to the Fraser car company in NZ about that nice rocker they use. Hopefully they'll share the information. Their cars have some nice touches. Here's a shot of their front suspension. Nice clean design. The lower front control arm looks like the one I'd like to build. The headlights can be removed by loosening a couple of bolts, great for track days. And check out that brake rotor!
entry 1086

December 19, 2005:
With the best of intentions, I cleaned the dead birds out of the woodstove and fired it up to make the garage habitable.
Then I tackled the hood. First off, the cheap clamps you get at Harbour Freight aren't worth buying. I persevered in my hammering of the flange along the bottom edge of the hood. When I tried it on the car, it looks as if I was slightly off in my location. I was paranoid about making the hood a bit too big. Turns out I had the opposite problem and ended up a bit too small. I was not happy when I saw the gap (1/8" to 1/4" estimated) between the hood and the top of the body. can I still use this hood or will I have to start over? I don't know. I'll take another look tonight and see what I think. I'll take pictures too.One other option for the hood would simply be to cut the louvres out of my original and rivet the panel back in the other way around. It wouldn't be the most attractive setup though.

With regards to suspension, John Grimberg contacted me and is willing to help out with machining a custom rocker. Time to fire up the computer and figure out what that rocker should look like then!
entry 1087

December 20, 2005:
I was hoping that after a bit of time, the hood fitment would either look fine or some easy solution would pop to mind.
Nope. It looks like I'll have to start over. I'm going to start from scratch and make a new pattern at the same time.

I'm heading back to Canada for a couple of weeks. Not much will happen on the Seven during that time obviously. Hopefully I'll come back all full of plans and motivated to at least get the hood, exhaust and fender repair done.
entry 1088

A shot of the hood fitment.
Or the lack thereof. Sigh. I think my slipping clamps are partially to blame. The crease would look far nicer if I had access to a metal brake that was large enough.
entry 1089

January 5, 2006:
Happy New Year!
Okay, it's time to get serious about the Seven again.

Mark Rivera has offered to cut the hood, punch louvres and bend the two lips for me. It would have to be shipped to me but it's a tempting offer. Mark's building a car of his own. I've also been considering moving to the 0.040" aluminum instead of the 0.050" I used last time. It saves a bit of weight and the louvres will stiffen things up. I'm not sure about that but it will make the bending easier. Time to play with the existing hood and see.

I started trying to model the front suspension in SolidWorks last night, only to discover I have a lot of learning to do with the program. I'm still not sure if I should write my own analysis program (I like building things), use an existing Excel spreadsheet, write my own spreadsheet or use SolidWorks. The latter is tempting because it's such a cool program. Time to do something, though. I want to have the car up and running again by spring. I guess that means it's time to fix the rear fender that was ripped off too. So many plans!
entry 1090

January 6, 2006:
I figured out enough SolidWorks to put together a line drawing of the suspension that lets me bounce things up and down.
Whee, this is fun! I need to double-check the dimensions of the various parts though. While the suspension movement looks familiar, my control arms ended up more parallel than they do in pictures.
entry 1091

January 9, 2006:
You know, I really should choose one thing and focus on it.
I seem to be suffering from vehicular ADD again. A fresh load of Mini magazines has me thinking of cool, fun things to do with the Mini. I've started to get the itch to run my Land Rover, Basil again. I want to start working on my house again. And of course there's the Seven. I have a long list of things I'd like to do. And one I don't - the hood.

I'll measure the car up again tonight to see if I can figure out how the front suspension works. I really hope my Solidworks model isn't correct. It shows a camber curve that isn't enough to compensate for body roll, putting the tires into positive camber immediately. Well, if anyone wants a set of dimensions for a suspension that has a whole bunch of bad habits, I'd be pleased to oblige.

Meanwhile, I've been considering the other laundry list of modifications. One is to move the battery up to the front of the car. Space is a little tight, so I'm considering a little Odyssey PC680 or the Hawker G16. I can get one for around $80 and it has the same long-lived construction that I'm used to seeing in Miata batteries. It's also only 15 lbs. Granted, I've had to jump the Seven a couple of times with my current Miata battery but that's because it wouldn't start for other reasons - fouled plugs. I figure a set of jumper cables are now standard issue for going to the track. There's also the matter of the fender. A tempting solution would be Coveland's aluminum fenders. There's also a good rear view mirror that would come in handy at Mirrors for Sevens. I saw one on the RMSC car at Aspen. Argh. Concentrate! Concentrate!
entry 1092

The first model of my current front suspension, with a few degrees of roll.
I need to recheck the dimensions, but check out what's happened to the camber! Nothing good.
entry 1093
<< | show individual entries | >>