Archive for the Handling Category

Update

Posted in Handling, Traction Control, Uncategorized on April 4, 2014 by David de Regt

I took much of last year off, made some poor suspension choices, and didn’t pay much attention to the car.  I got my butt kicked in most events I went to, and wasn’t very happy with the car or my driving.  In the end, though, it gave me what I needed — most of a year off.  I flew around the country and codrove with the Woottons a few times, autocrossed a bunch of random cars, and had some fun anyway.  I also noticed that, despite lots of attention to the car everywhere I posted it for sale, no one even sniffed around at a real offer, so I know that, someday when I do actually sell, parting it out is the way to go.

1530326_619095470648_962636239_n[1]For this year, I’m going to make a little more of an effort again.  We moved into a new house last year and didn’t have a good way to deal with the towing situation, so this year my dad sold his giant trailer and I bought a tiny little trailer, perfect for a Miata.  Most importantly of all, I can back the trailer, with the car on it, into my garage, and leave it there, ready for an event at any time, with the truck parked in front of it.  I’m hoping that I’ll find a lot more motivation to autocross when it means spending 5 minutes in the morning and 10 in the evening loading/unloading instead of 2+ hours on each side getting the truck/trailer to/from my parents’.

I decided to attack some of my root annoyances with the car as well this year.  At the end of last season, I realized that my traction control system was a little flaky.  While it often helped, it often cut in when it had no reason to.  I spent some time debugging it at the first event this year and learned that it is, in fact, cutting fuel even with the system completely disabled — when I bypass the unit and plug the injectors directly into the ECU, it runs perfectly.  I’ve been working with RaceLogic the past couple weeks trying to narrow down what the problem actually is.  So far, we think it’s the adjuster unit, but it will require further diagnosis.  Until I get that sorted out, the unit is staying fully disconnected, forcing me to learn how to modulate a gas pedal — something I’m not very good at, apparently.

intake[1]Another big annoyance was the general tune of the car.  In addition to feeling like I didn’t have enough power, there was always a bunch of hiccups in the tune (above and beyond the RaceLogic-induced ones).  Throttle pump (tip-in) was always sketchy, leading to unpredictable power levels on corner exit.  At 2012 nationals we noticed that underhood temps were crazy, and put a hole in the hood for the intake.  Since then, I’d switched back to a more traditional intake, but pulling air from the driver’s side headlight area.  I also upgraded to Flyin Miata’s big flex fuel kit, which is a pretty awesome setup, and upgraded to ID1000 injectors in preparation for E85.

miatadyno_20140302[1]Last spring, I changed from an AEM to a Hydra Nemesis for an ECU, and immediately was able to improve the drivability of the car quite a bit.  However, it was still far off what I wanted/needed it to be for consistent driving.  I gave the car to Kris Osheim of KO Racing early this year and he spent a few weeks road tuning it to help with drivability and low end torque.  The car is an entirely different beast now — mashing the gas at 2000 RPMs produces an instant wall of torque, and different rates of tip-in actually produce linearly proportional amounts of power.  Using the flex fuel setup, I can now put anything from full pump gas to full E85 or any mix in between, and the car fires right up and makes a safe amount of power for whatever ethanol mix I’m running.  The car now makes 359rwhp/279rwtq (Dynojet corrected) on E85 and 316/256 on 92.  The old power numbers were falsely inflated by the previous dyno I was using — he applied a fixed 20% correction factor, so this is actually quite a huge bump in power over the old setup.

Suspension-wise, I knew I needed to change things.  In 2012 I was running 700/450 springs, and based on the math said we should be running 800s in the front, so for the 2013 season I tried just bumping to 800s.  Of course, the car went from fairly well balanced to ultra-pushy.  I spent the limited season trying to dial it out with shock adjustments, but for 2014 I went up to 550 rear springs and added a small rear swaybar.  Two events into the season, the balance of the car is proving to be a huge improvement over last year, which makes it a lot more fun to drive.

The brakes had always been a big complaint of mine with the car — they were a little unpredictable and, especially on concrete, you were essentially unable to bring the car into ABS.  For 2013, I upgraded the fronts to Flyin Miata’s little big brake kit with the 11″ rotors, and went to a 1″ 929 master cylinder with a dual diaphragm brake booster, which were a huge improvement.  I’ll likely upgrade the rears to their rear little big brake kit this season as well, but I haven’t pulled the trigger on that yet.  I’ve also changed out the rear wheel bearings and front hubs for this season, as they were starting to get some play in them noticeable as pad-knockback after hard cornering.

I’m planning on attempting to get the car out to several big events this year — Crow’s Landing, Packwood, Spring Nationals (Lincoln), and Nationals.  There’s still a bunch to get working on the car for real — Eric Anderson’s car proves how effective the RaceLogic can be if I can work the demons out of my system, dialing in the new suspension setup, and learning how to drive a car that can break the tires loose at will in a straight line in 2nd gear on Asphalt.

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Packwood ProSolo

Posted in Handling, Prosolo, Traction Control on July 8, 2012 by David de Regt

The ProSolo was an interesting weekend.  The course was the most annoyingly not-fun collection of ridiculously tight offsets and stupidly slow corners that I’ve ever driven.  I feel like, in 8 years of autocrossing, I have to have driven a less fun course than that, but none come to mind.  On the upsides, I managed to squeak out a win (barely — 0.009 seconds) and it highlighted a lot of things to focus on for the next phase of development for the car.  Also, we had zero reliability issues with the car again, so I’m just waiting for something expensive to explode at this point…

One of the big obvious weaknesses this weekend was power application.  I think that part of the problem with my current build is the forward weight bias (we’re at about 56% front right now), which isn’t leaving any weight on the rears to put power down.  I’ve been working on a design to try out that will let me drop down to a 1.6 motor, non-intercooled, which would drop a ton of weight off the front end, and potentially give me room to ballast up the rear.  In the interim, I need to explore a fuel cell so we can run less fuel without starving, allowing me to ballast up the rear a bit.  I’m starting to wonder in general about just running more fuel after seeing Sam Strano, a man who is already heavily ballasted, running a full tank of fuel in his SS C6 Corvette, because the extra power application he gets out of the weight over the rear is worth the weight gain from the gas.

An unrelated huge problem this weekend was that my front splitter wasn’t playing nice with the Pro light sensors. I could get the car to “stage” in a couple different places, and it was very hard to tell which one of the two places I was staged in.  As a result, when runs really mattered, I had to run extremely conservative lights (7xx-8xx) just to make sure I wouldn’t redlight.  If I’d hit the deep stage hot spot, then I’d still redlight even waiting that long (see my first run of the challenge, for example — 498 redlight, and I didn’t even start to release the clutch until right before the GREEN light came on, so I must have been deep staged millimeters from the next sensor…)  I’ve emailed Howard Duncan to ask how high the lights are, so I can make some “endplates” for my splitter to make sure that I hit the sensors in a reliable place at the next event.  This problem made every run an unpredictable nightmare.

I also need to just learn how to launch.  I cut everything from a 1.935 to mid 2.2s 60-ft times all weekend, mostly doing around 2.10ish, which is pretty terrible.  On low grip asphalt, even after the course rubbers in, the car has enough torque to break the rears loose at basically any point in first gear, so it’s extremely hard to find the balance between a little bit of wheelspin and way too much wheelspin.  I’ll hopefully learn eventually, but until then I’ll be running almost STS 60 foots while I burn up expensive rubber.

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Packwood National Tour

Posted in Handling, Reliability, Suspension, Traction Control on July 2, 2012 by David de Regt

The whole month of June has been filled with rainy weekends that we didn’t even bother bringing the car out to autocross in.  One of the downsides to running a high power car is that, in the wet, you just get hosed on PAX.  So, as little fun as I have autocrossing in the rain in general, it’s also uncompetitive, so the idea of towing for 3 hours each way to get creamed in the rain is unappealing.  Seattle might not have been the greatest place to build this car…

Fortunately, it gave me some time to mess around a bit with the car.  I bought a 12+1 tooth crank trigger wheel from Trackspeed Engineering, and after ~20 hours of trying to make it run reliably, I gave up and switched back to the stock wheel.  I don’t know if there’s noise on the crank hall sensor from something or if the AEM just doesn’t like getting that many tooth updates, but it’s off the car until I have time to spend more time debugging.  I replaced both the cam and crank angle sensors with brand new ones from Mazda (they had absolutely no effect on the 12+1 wheel, incidentally,) and replaced the main relay (the relay that broke in Lincoln) while I was in there, which, interestingly, had been superceded by a much different part.  We also learned that we’re not allowed to run shoulder harnesses in a non-rollbar-convertible, so we pulled the 4/5 point belts and put in simple lap belts, which removed a bunch of weight from the car and made it a lot easier to get in and out as well.

After having no problem with power application in Lincoln (and even limited problems with power in Packwood,) I upsized the crank pulley (that the SC feeds off) from 120mm to 125mm, and spent a bunch more time on the dyno.  We’re up to 330rwhp and 258rwtq and spent a lot more time on the low RPM portion of the map.  The car is now faster and has much smoother power ramp-up, so it’s more drivable too, and is better at putting its power down than it used to be.  I think this will be the end of my attempted power mods before 2012 Solo Nationals.  It’s time to work on the suspension setup and on my driving.

The 2012 Packwood National Tour arrived in a real hurry.  I spent 2 weeks messing with the trigger wheel to no avail, and had to rapidly switch back to the stock wheel on the Monday night before the NT.  Wednesday the car went in to get a new muffler, since we were consistently blowing 102dB at Lincoln (over the limit.)  Thursday I spent 3 hours on the Dyno at Pina Motorsports, and then 6am Friday morning we pulled out from Redmond to head down to Packwood.

The practice course was the dirtiest (gravel/etc.) course I’ve ever driven on, but we did some rough shock tuning and the car was working really well.  Ironically, both of our paddock-mates’ cars broke, so we spent some time helping fix them.  The rest of the weekend, the car performed perfectly (despite us driving it inadequately,) and I managed to put a 1.776 second victory on the class, running fairly consistent times.  At the end of the weekend, we rolled the car onto the trailer and drove home, ready for the Pro in a few short days.

We learned that the car’s fuel starving at around a third of a tank, which will require some investigation after the ProSolo.  I am also sure at this point that the car will be faster with more confidence-inspiring brakes, so that will be another focus for after the ProSolo.  The traction control also needs some further tweaking, and the wing really needs some string+video attention and a Gurney Flap.  Time, time time…

Here’s some videos of my fastest runs for the weekend (expand for 720p.)  As you can tell, I’m still driving the car incredibly abruptly.  It’s still more than a bit of a shock, coming out of stock class.  At this point, I have at least as much speed to be gained in learning to drive than will be found with further car setup…

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Spring Nationals

Posted in Handling, Reliability, Wiring Harnesses on May 29, 2012 by David de Regt

Because of the alignment and truck issues, we, of course, had another frantic last minute prep session.  We spent Monday afternoon pulling the front UCAs off to bend them more, reinstalling them, and getting the car to an alignment shop with zero notice in time for them to work on it.  While some of that was in process, we had to pull the alternator off the truck and get a rebuilt alternator and install it.  That evening we finally got to clean up some last minute stuff on the car and packed up the rig to head to Lincoln.

2 days of towing later, we arrived to glorious 90 degrees and humid Lincoln, NE.  We spent Thursday doing practice starts to figure out how to launch the thing (which neither of us ever got any good at – my best 60ft was 2.01s.)  Everything was going well, so we retired to beer.

Friday (ProSolo day 1) morning, I got 3 runs then the car sputtered and died sitting in line to take my 4th run and wouldn’t restart.  We pushed it off to the 2nd driver line and let it sit for a minute.  We checked everything – nothing obvious was wrong, but a minute later we tried firing the car back up, and it happily did.  My dad then got 2 runs in before it died in the same way for him and we retired to impound.

Very perplexed, we guessed it was a fueling issue, and I’d been worried about my fuel pump since the Packwood weekend of harness melting/shorting.  So, at lunch we changed the fuel pump to the new Deutchwerks pump.  I didn’t get a right side run (apparently I rolled out of my one right side run, grr), so my dad got to go first.  We sent him out without a hood for afternoon runs, on the off chance something was overheating, to get some more ventilation into the engine bay.  He got his 4 runs in, so we hoped it was fixed and put the hood on for my runs.  I got one run before it died again briefly after I departed for my second run.  We again retired to impound and had an evening to consider.

Fortunately, I had noticed, when it wigged out on me, that the tach was going nuts, implying that the ECU had lost cam/crank sync (or something far more heinous, possibly.)  I asked around the paddock and found two very nice competitors (Bill Schenker and Mike Heinitz) that had spare crank and cam angle sensors to loan me, and swapped them onto the car.

The next day, we decided the better part of valor was to run without the hood again (but we “replaced” the hood with a strip of tape, which is technically legal under SSM rules, stupid as that may be) and I went out for my runs.  The car had no issues, and I managed to save for 3rd place, and my dad also got his 4 runs in without issue.  When we tried to start the car up again after weighing it, it wouldn’t start, or even show any signs of ignition signal.  We towed it back to the paddock and poked around at it for a bit.

I found nothing wrong, but finally decided to try swapping the main relay out for a spare I had lying around, and the car sprung to life.  That relay had likely been damaged in the wiring debacle of the Packwood weekend, but it’s still a little distressing.  The car seemed fine after that, so we declared victory and went for celebratory BBQ and beer.

The NT went mostly without issue.  They yelled at us after the ProSolo, because apparently our exhaust was blowing 103dB consistently (limit of 100dB), so we had to attach a clamp on muffler for the tour.  I had a small power burble on day 1 in the middle of my third run, but it’s vaguely possible it was just fuel starvation.  We made it through — I got 3rd again, 1.4 off the win.  The only day two issue was when, on the way out to grid for our day 2 heat, my dad drove the truck over the hardtop I’ve been using to keep the car dry/sealed overnight, which is now forcing me to come up with some new solution…

On the drive home, so far, I’ve ordered brand new replacement relays from Mazda and also new crank and cam angle sensors.  I noticed the cam sensor and the main relay had both been superceded, and reading up on miata.net, it looks like my issues are pretty known issues, so I’m vaguely hopeful that I’ve discovered the cause(s) of my more major problems.

We also had a chance to play with the Hoosiers vs. Goodyears at the Prosolo, and we both agreed that the Goodyears make the car much more drivable, so for the forseable future, it looks like it’s going to be a Goodyear car.  They seem to be able to put down power much better, and also they don’t overheat nearly as badly as the Hoosiers do, both of which are good things for an SSM car, especially at a hot site like Lincoln.

I hopefully will have time coming up to work on some of the other projects for the car: a front brakes solution, possibly moving to a permanent carbon hard top, venting the hood for real, tuning the rear wing, canards, etc.  The really short summary, though, is that the car, for its first showing, when it was working, proved that a Miata can get it done in SSM (if I stopped driving like such an idiot.)  So, despite all the other stresses of the weekend, it was a resounding success.  I also had some more time to mess with the data system that I’m developing, and worked some of the usability kinks out, which was helpful at the events and should be even more useful as the year goes on…

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Second Packwood weekend and Spring Nationals Leadups

Posted in Delays, Handling, Suspension, Traction Control, Wiring Harnesses on May 29, 2012 by David de Regt

It’s been an incredibly hectic two weeks.  I spent a couple days tearing into more of the electrics and found that the fuel pump wire down the driver’s side of the rear harness had rubbed through to the chassis, which is probably what started everything.  I ran a new thicker gauge wire and re-loomed/moved some of the harness, so it should hopefully never rub through again, and the thicker wire will be less prone to heating.  I also ordered a Deutchwerks 300LPH pump due to my decreased confidence in the Walbro, intending to use it as a spare if the Walbro died.  Finally, I moved the fusebox out from under the side of the engine bay into a spot near the intake with some airflow, in case it just needed some ventilation as well.

The subframe that we were told existed wasn’t actually the right subframe, which we didn’t discover until after close of business Thursday night.  We got to wake up early Friday morning and call every parts shop in the area to find a new subframe.  The only one we could get before Monday wouldn’t be pulled until 5pm that night, 2 hours from home.  So, we picked it up, got back home around 7:30pm, and spent the entire night swapping the subframe and front control arms.  Shaikh finished up the shocks Thursday night and overnighted them so those arrived Friday morning, and when we finished with the subframe, we got to also assemble/swap the new shocks (mounting canisters, etc.)  Around 11:30pm we finally finished with all the work, then spent until almost 2am doing a ride height set and string alignment.  We realized the alignment wasn’t going terribly well, and we couldn’t get enough camber out of the front anyway, so we called it good enough for a shakedown and went to bed.

We decided that waking up in 3 hours and driving to Packwood for the morning session was out of the question, so we went down for the afternoon, which was a nice dry day, and had no major issues at all with the car.  The car was pretty loose, but still drivable, and we settled into liking a RaceLogic setting of 20% slip and 5.0mph wheel differential.  Sunday morning we woke up to a wet ground and ongoing rain, and we ran a very wet morning session, where we got to throw on the Hoosier Wets (225/50/15 H2Os on 15×9 6ULs) and play with the RaceLogic to figure out a wet setup, which worked out quite well.  We tried 5%, which seemed pretty good, but 10% was really the sweet spot, if you had quick enough hands.  The car is remarkably drivable in the wet, which is good to know.  On a very representative course, I was only 0.4 behind the Hyman GT-R car in full wet trim, which is closer than I would have hoped to get.  We had no issues with the car in the wet either, called it a day, and drove home.

On the tow home, the alternator on the truck let go, though, adding some more insult to the existing injury.  Nothing is ever easy…

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Test Run – Phase 1 Complete

Posted in Delays, Handling on April 16, 2012 by David de Regt

The past several weeks have been on and off busy and not.  Even though the car dynoed, there were a lot of loose ends to tie up.  I had the car aligned and ride heighted while I got some work done the next day, and we had an emergency all day session on Friday trying to finish the car in time for going out to a karting track (that allowed cars that day) — seatbelt installs onto the firewall, custom bracket for passenger seat, fender and bumper cutting to fit the giant tires, front swaybar install, etc.  We decided not to bother going down to the kart track by the time we finally finished up all the last touches (weather/lack of daylight to make it worth it), but at least the car was drivable.

Instead, Brian and I spend Saturday doing a bunch of work.  We measured bump travel vs offset for the front and rear of the car, to plan the new uprights, and then took the car out for its first spin (turned out to be a gorgeous day, but with no autocross all weekend anywhere in the northwest).  The car worked great and we dialed in the Throttle Pump settings and had some fun.  The car was showing signs of being incredibly loose, but we didn’t care too much at the time.

Over the next week, I continued tweaking things.  I built a temporary intake out of cheap parts, we added some lexan panels to the hood to block water getting all over the headlights, I added a cabin-switchable intercooler fan, etc.  There’s so many little things to do building an SSM car.  The weekend had an event in Packwood, but it was going to definitely be rainy (100% chance of rain both days) so I ordered a set of 15×9 6ULs and some Hoosier Wets on Monday, which ended up having 3 come in Friday and one come in Tuesday (good job UPS), so I missed that weekend of events.

Fortunately, the following weekend had a gorgeous pair of events up in Vancouver.  My dad and I towed the car up and ran a PCA event Saturday and a VCMC event Sunday, where the car showed great promise.  It turned out to be at least as loose as we anticipated, but it was still keeping up with CSP cars on a non-power course (we checked the datalogs, and were both over 60% throttle for a collective less than 1 full second).  In any event, my dad signed on for codriving for the rest of the year, which should make for a smooth first year of towing to events.

The car’s waiting for several things right now.  The shocks are taking a little longer than originally anticipated, the wing pushed out a couple weeks longer than they thought, and the EPMiata upper control arms are also being pushed out a couple weeks.  As a result, even though there was an event this past weekend, I didn’t figure on there being much point in running it, as the car’s current handling is largely a result of the temporary suspension setup on it.  So, instead, I brought it into the local body shop to start prepwork on painting it, and over the next week or two it’ll get painted while I wait for the rest of the parts to come in.  I’ve abandoned my San Diego entry and I’m aiming at the Lincoln double now, which should actually be doable…

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