Targa Miata
August 9, 2007 - A lot of little jobs got done on the car tonight.
The most obvious underhood is the installation of the red valve cover - that's an instant 15 hp gain for sure, although I need to get a filter for that cam cover breather. I installed an interior rear view mirror, the plastic cowl at the base of the windshield, cleaned up a bit of wiring, changed the throttle cable bracket and generally did a few small things on the car.
The Mazdaspeed MX-5 turbo muffler sounded terrible, so it's been replaced by a Flyin' Miata part instead. That sounds a lot better and also drops a few pounds. I also determined that my recent addition of a no-slip patch was a total failure, as it started to creep around the footwell and announced itself to be a hazard. So it's gone now although the bits on the pedals remain.
The car's heading for the alignment shop tomorrow morning and then on to the dyno to get the engine into shape. It's part of the push for the track debut at the Flyin' Miata open house.
entry 281 - tags: ergonomics, exhaust, alignment, engine
August 13, 2007 - Car gallery added to the website.
After being innundated with a request, I've put up a gallery of the car from a bunch of angles. Yes, it's completely self-indulgent. But I don't mind at all.
So, if you'd like a Targa Miata wallpaper or just want the chance to critique the stripes carefully yourself, check it out: Targa Miata gallery.
Meanwhile, the car got aligned today. A bit of tuning on the computer and it's ready for the track. I've been driving it around for the last few days. I'll post some driving impressions soon.
entry 290 - tags: alignment
September 28, 2007 - Sway bar time!
I have a good selection on hand. For the front, a 23mm front bar from a Mazdaspeed MX-5, a 7/8" adjustable aftermarket bar and a 1" adjustable. The rear will be served with a 14mm Mazdaspeed bar or a 5/8" adjustable. I'm trying a different setup than I usually use to ensure the rear wheels stay hooked up on rough surfaces. We'll see how this works out. I might see if my local alignment shop is willing to work with me on this, I expect it'll be spending a lot of time on the rack.
entry 318 - tags: suspension, alignment
November 1, 2007 - The reworked shocks are here.
These shocks are the ones I expect to use for the Targa. They're made by AFCO, a US company that has experience in both road and dirt track racing. They're pretty exotic and have a number of features designed for maximum durability and traction. I've been hugely impressed in dealing with AFCO so far, having a number of long discussions with the engineers about the damping, stroke and bumpstop design. These shocks will become part of the Flyin' Miata lineup, and they are definitely a custom item built to the Miata's needs.
The new shocks are quite a bit different than in their original configuration. For example, the fronts have a 2" longer body. After installing the original set, I made a number of measurements and sent them off to AFCO. From this, just about every component of the shocks was changed - the upper hats were shortened, the bodies changed in length and the shafts altered. Now I have the exact travel range I requested. I can also run the car a bit higher than I did before - not something that other Miatas will necessarily want, but it'll give me the ability to absorb all sorts of rough surfaces. Eric wants me to jack the car up to Paris-Dakar levels, but that might be a bit extreme.
One nice side effect is that they're also easier to install. Not that this is a critical aspect of shock design, but I sure appreciated it when it came time to put them in.
Today I'll cornerweight the car, then get it aligned. I'm experimenting with alignment settings that are closer to those used in Spec Miata, unlike the street-biased ones I've used in the past. The testing on Saturday will be used to determine how it works.
entry 331 - tags: suspension, alignment
November 1, 2007 - Cornerweight time.
This wasn't a very serious cornerweight session, as I'll be taking the suspension apart before too long. I mostly wanted to make sure there weren't any really major problems, and to set the ride height.
The car's fairly tall, as fast Miatas go. It's about 13.5" front and rear, although I need to recheck that after driving it home tonight.
The real question is - what does it weigh? A quick disclaimer first, I always weigh cars with a full tank of gas. Not in this case, because I forgot to fill up on the way in to the shop this morning. The car is showing 3/4" on the gauge. I'll fill it up on the way home and then add the weight of the fuel so I can get a good, comparable number.
Anyhow, with the 3/4 tank, the car came in at 2080 lbs. Not bad! It's nose-heavy, with 53.1% of the weight on the front wheels. That's okay, I'll have more weight in the trunk during the race and the occupant weight lands more on the rear than the front. I'm pretty happy with that. My target weight was 2070 lbs wet, and I'm pretty darn close.
update: it took almost exactly 4 gallons to fill the tank. At 6 lbs/gallon, that means the car is just a hair over 2100 lbs with a full tank. The final choice of sway bars will affect this, as will the installation of the rally computer - but it's a good start.
entry 332 - tags: alignment, weight loss
November 2, 2007 - Alignment time.
I'm trying a new alignment on this car (because I'm not trying enough other new things!) that has a fair bit of negative camber up front. I was aiming for about 2 degrees. Unfortunately, the right front wheel refused to cooperate, and the alignment tech was only able to get 1.2 degrees. Not what I was looking for! Part of this is due to my relatively high ride height, but the left front didn't have any trouble. So I'll be inspecting that area of the suspension later for problems. It didn't show up the last time the car was on the rack because I was aiming for far less negative camber and I had a lower ride height. It is odd, though, when I had the car on the lift yesterday I checked all the cams and they all appeared to have a lot of adjustment left.
The resulting setup has about the same camber front and rear while I had been planning on a slight front bias. I hope my collection of sway bars will allow me to make the car handle reasonably well. It doesn't really matter much, though, as I'm going to have to test all over again once I find my missing camber. Sigh. At least I'll be able to spend some more time on shock settings, the rest of the testing won't tell me much. Instead of a test session, it's going to be more of a play session. It's a shame, I don't have another opportunity at this track until May and it's a fairly major expedition to get there.
entry 333 - tags: alignment
November 12, 2007 - This wheel used to have about 1.5 degrees of negative camber.
Now, it has none. A quick check with the toe plates indicates close to an inch of toe-out. Once I'd pulled the shocks out again (they're going in a street car for final evaluation as a Flyin' Miata product), I also pulled out the lower control arm on this wheel. Yup, looks like a crease in the top. That would explain the alignment problems.
Honestly, after bending a wheel like that, I'd be shocked if the control arm hadn't bent. They're intended to be the weak point in the suspension, absorbing the punishment to protect components like the subframe. I'll stick another control arm in, that's an easy fix.
entry 339 - tags: suspension, alignment, crash
July 25, 2011 - Time for some camber.
With the current ride height, it's hard to get much negative camber in the suspension. Almost none in one corner, actually. I've tried a couple of different control arms, but it was time for more dramatic measures. V8Roadsters stepped up with a half set of their tubular control arms: a pair of front lowers and rear uppers. These particular arms have an extra camber adjuster built in, allowing me to cant the wheels in as much as I like. One really cool thing about them (other than the bright red color, of course) is that the new camber adjustment is independent of toe and caster. The front toe is affected a bit, but that's easy to adjust. So I'll be able to play with my setup in pit lane without having to worry about interrelated settings.
The only downside? I used to tie the car down via a big hole in the front lower control arms before. I can't do that anymore!
entry 884 - tags: alignment, suspension, control arms
August 10, 2011 - Time for some work on the car.
I put it up on the lift yesterday and came up with a good to-do list. One of those items was to deal with the slipping alignment cams. The red powdercoat on the new arms - and on the subframe as well - was part of the problem, so I took it off. I also used a file to roughen the back of the washers on the cams and tried to avoid getting any lubricant on them. Between that and some good strong torque, things should be good in the future. But we'll mark the cam locations once the car has been through final setup before the race.
I also swapped in my 400 lb rear springs. I'm looking forward to how it will feel.
entry 903 - tags: alignment, suspension
August 20, 2011 - Off the lift and on the road.
It's time to get the engine tuned properly and make sure the suspension setup is good. Basically, everything needs to get the final shakedown.
The alignment will be sorted out in a few days. One nice feature of the V8Roadsters control arms is that I can play with camber to my heart's content without messing up the rear toe or the front caster. I'm still fine-tuning the damping settings for the 550/400 spring rates, but that should go fairly quickly.
The big thing is the engine. I've decided to take a different tack with how to set it up, and things are progressing fairly quickly. I'm just setting up air/fuel ratios without using a MAF at the moment, and it's possible I might just run that way during the race. We'll see how well the MAF dials in. Once it's all set up, the long-term fuel trim will make sure it stays that way.
As part of the fuel tuning, I'm working through the entire repertoire of the engine: low rpm, high rpm, low load, high load, etc. And at higher rpm, when I nail the throttle this car just boogies. It's still a bit rich down low so that will get stronger as I keep working.
entry 918 - tags: tuning, alignment, suspension, testing
August 27, 2011 - A final check of the undercarriage.
The car's just back from the alignment shop, where they set up the caster and rear toe. The control arms are set for maximum camber using the factory adjusters, leaving the extra adjusters on the V8Roadsters control arms for me to play with. I'm taking a last trip to the track tomorrow to just double-check the handling balance and scrub in the race tires a bit. I haven't spent anywhere near as long on the handling setup this time as I did last time, but that's because the car is such a good, solid platform now. I've been experimenting with it for about four straight years. So I know how to quickly make the adjustments I need to make it work the way I want.
Meanwhile, Brandon is busy doing the last-minute prep on Nancy. Mounting emergency triangles, packing his on-board tool kit, etc. He's also chased down a couple of odd noises. The one thing that is giving him trouble is the trip computer. It's a Terratrip, and we originally purchased an interface box so that it could use the car's electronic speedometer signal. But it turns out that the NC Miata doesn't actually have a separate speedo signal if the car's fitted with ABS. The car figures out road speed from the wheel sensors, and it's all passed around via the CAN-BUS network. So scratch that idea.
Then he discovered the Vehicle Speed Sensor that's used on the non-ABS versions. So he ordered one of those and popped it into the trans...and it's didn't work. It turns out there's a small pin in one of the shafts of the transmission that triggers the VSS, and it's not there on the ABS cars. The hole is, but short of disassembling the transmission it's not an easy retrofit. So now he's going old-school and putting a Hall effect sensor reading off the driveshaft bolts. Lots of fun!
The big trailer with the cars on board will be leaving Grand Junction on Wednesday morning. Almost there...
entry 929 - tags: trip computer, alignment, suspension
August 30, 2013 - Prep time.
I've got a track day coming up in a couple of weeks, the last one with the current drivetrain. I'm going through the car to make sure it's in good shape. After the little three wheeled off-road excursion at Mazda Raceway Laguna Seca, I had the alignment checked. Every time that's done, I go over all the alignment cams and make sure they're torqued good and tights. I also mark them so it's easy to reset the alignment should one slip. Easy to do, but saves a bunch of potential hassle.
That tan Monterey sand is EVERYWHERE.
entry 1092 - tags: prep, alignment, suspension