build diary

February 13, 2005:
Yesterday was spent in the shop, working on the front end.
I've been concerned about my tie rods for some time. Specifically about the angle reached by the rod ends at full droop. Close examination proved my worries were well founded. The rod ends were acting as a limiter on the suspension travel. This isn't good - eventually the rod end tires of this game and breaks. Much excitement ensues.

A few weeks ago, I tracked down some 1999 Miata steering knuckles. They had a slightly higher steering arm to help this problem. I also decided at the same time to change over to ball joints instead of rod ends. They're not as adjustable as the rod ends, but they are more durable and were designed for this specific use. This meant new tie rods. No problem, I had a few of those.

Imagine my surprise when I discovered that Mazda apparently used two different sized threads on their tie rod inner joints. I figure the most recent set I'd picked up were from a 1999 or later car. I discovered this after I'd cut one in half, of course. One of my "new" tie rods had the larger thread I needed but I was forced to cut up one of my rod end versions for the other. I wasn't planning on using it again but it would have been nice to have the option!

It took a bit of time, but I'm much happier about the steering setup. It seems to be just as sharp as before and there is absolutely no slack or clunk if I wiggle the wheel at a standstill. On the road I feel as if I'm getting more kickback but that must be my imagination.
entry 786

The steering at full droop.
The rod end is acting as a limiter - not good!
entry 787
Despite some grinding I'd done, it's obvious the rod end is chewing on the steering arm.
There were marks on the rod end as well.
entry 788
Surprise! Mazda has used two different inner tie rod threads over the years.
entry 789
Measuring the length of the tie rods.
The steering rack was centered and a ball joint was installed on the steering arm. The wheels were set to 0 toe and the distance from the rack to the inside of the ball joint was measured. The tie rod was built about 7mm longer to allow for adjustment.
entry 790
The new ball joints installed, along with new uprights painted a nice satin black.
entry 791
I'm very happy with the black exhaust.
It hides a number of sins and looks great.
entry 792

February 20, 2005:
Every moment of my time has been spent working on the book.
I'm trying to make it entertaining to read as well as technically useful. All this writing has meant that I'm not working on the Seven. Well, sort of. I spent today with the car strapped to the dyno, trying to get back my "missing" power. The second dyno run was 134 hp at the rear wheels, right where this engine should be. However, I had problems with a lot of variation between runs. Odd. The fuel filter was changed and a feed line rerouted as the car was starting to show signs of low fuel pressure again and that helped, but I still never hit that 134 again. It was a bit frustrating - but I gave up and started work on installing the individual throttle bodies that we have sitting on the shelf at Flyin' Miata. It took a bit of creativity to get them to work with the stock throttle cable but I have that sorted now. Eventually I managed to get them installed and the injectors proceeded to leak quite enthusiastically. It turns out that the special fuel rail also includes special little clips to hold the injectors in place. Very cool. Now, before I fire it up, I'll have to install new injector connectors (easy) and plug up a coolant line (easy). Then the hard part starts - can I get it to idle?

I've also been doing some shopping. The snowmobile trailer I used to tow the Seven to the track last time worked fine but it was quite an adventure getting the car on it. I've decided to buy a real trailer for the car. I'd build my own but I'm frankly just too short on time. I found a used one that has a 6x12' deck on it for not much more than it would cost me to build. It needs a bit of love but nothing major. I'm building my own little race team! Now, where can I park it?
entry 793

February 21, 2005:
Did I mention I have better things to do? Today I picked up my "new" trailer.
It needs a bit of love (don't we all?) but it should do the job beautifully. I also managed to get the Seven running on the new throttle bodies. It idles fairly well considering the rough state of tune and makes an intoxicating noise when I blip the throttle. Hee hee hee. Now all I need to do is determine if they're making more power than the stock part, and work out an air filter for them.
entry 794

Dyno time.
With the freshly built engine, I pulled 134 hp at the rear wheels. Woohoo! See it on video.
entry 795
I have better things to do.
But I've wanted to put these on the Seven for soooo long...
entry 796
My new trailer for the Seven.
Nothing fancy but it's perfect for what I need. Dig those wheels!
entry 797

February 25, 2005:
It's been busy at work, but I've been stealing a few moments here and there to work on the Seven.
It's been out for an initial test drive with the throttle bodies installed. Pops and crackles galore out the exhaust as the fuel tuning isn't even close to being correct, but the car runs. I'll put it on the dyno this weekend and see if I can sort things out a little more. There's also a bit of binding of the throttle plates that prevents them from closing 100% when cold, giving me a 2000 rpm idle. Still, the car drives and that's a start.
entry 798

Ready for a road test.
entry 799

February 27, 2005:
Not one of my more successful weekends.
I decided to start off by taking the Seven for a quick blast down the road to see how the fuel was set up. The fuel curves are obviously drastically different, so I pulled over and fiddled a bit. The car then absolutely refused to restart. A helpful Man With Truck took me back to the shop to grab the trailer and I brought it home. It has since repeated the trick - this time right in front of our shop doors - so I'll try it tomorrow morning to see if it's heat-related. I thought I'd found the problem but apparently not.

A mistake on my part meant a small hole in one of the radiator tubes, which stopped any chance of dyno testing this weekend. Well, it didn't have to. I managed to fix the leak but by that point I didn't feel like strapping the car to the dyno. A longer drive helped me dial in the fuel better so now it should be in the ballpark. Is it making more power with the new throttle bodies? I'll find out this week. I certainly hope so, otherwise I've wasted a lot of time.

Some bump steer testing proved to be inconclusive - an inch of rack height change brought about little change in the bump steer. Then, as I reassembled everything, I realised I'd forgotten to adjust the ride height for the boards under the front wheels. So all my testing was done incorrectly as I was at the limits of the lower suspension travel. It was that kind of weekend.

I did get some things accomplished, though. The trailer has now been fixed up with properly adjusted hubs, some frame reinforcements, a new place to hang my ramps and general fettling. It should be a nice little setup for the Seven as the car fits perfectly. Now all I have to do is register it! I also spent some time working on my girlfriend Janel's "new" Miata. It was modified with suspension and pretty much the entire Jackson Racing catalog. The 4" exhaust tip and drone at 3000 rpm was not to her liking, so we put on a stock unit and installed the rear springs properly. Much better!
entry 800

The trailer gets a makeover.
A mounting point for the newly modified ramps, reinforcements in various places and a repaired tire rack.
entry 801
Some bump steer testing.
entry 802

March 1, 2005:
The Seven stranded me today after I fixed the starting problem.
Well, I thought I had fixed it. So those throttle bodies are coming off. I just don't have time to sort them out before the various track days and trips coming up. Argh.
entry 803

March 3, 2005:
After about an hour of work, the Seven fired up happily with the original intake system.
It's a pity I didn't have time to work out the bugs in the throttle body setup. I'll have another shot at them later, probably in late April. Before then I have to finish the book, get the car ready for some real testing and chassis setup at the track and then take it to California. There's a track day at Pueblo next weekend. I'm going to be busy!
entry 804

March 6, 2005:
Partly for the book and partly because I didn't believe it could be correct, I put the Seven back on the scales today.
Yup, it is perfectly balanced when I'm in the driver's seat. Or when a limited slip diff and four dyno calibration weights are in the driver's seat, anyhow. The downside is that the car seems to have gained a little weight. The fuel tank was brimming and the new tires are noticeably heavy. Is that all? Well, other than gravel strategically placed in every nook and cranny, yes. Maybe it's time to start thinking about pulling some weight out of the car. Somewhere. I did raise the rear slightly so that the car sits level when I'm inside.

I spent some more time with the bump steer testing. Remember how I realised that my steering geometry was wrong some time ago? This forced me to move the tie rods below the steering arms, leading to the problems with the rod end limitations. Well, even with with my newly raised steering arms I still needed to either raise them further or drop the rack down. Maybe my measurements were done with the tie rods on the top of the arms after all. I suspect the truth is that I measured to the center of the arms. Regardless, I dropped the rack down about 1/4" (the limit without rebuilding the rack mount) and improved things fairly significantly. It's still not perfect but that will have to wait.
entry 805

The Seven goes back on the scales just to make sure.
It's gained some weight!
entry 806
More bump steer testing with an improved tool.
entry 807
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