Real Alignment

After last week's adventure with a spooky car I knew it was time to get serious with a proper alignment.  The DIY approach with toe plates can give good results but there is no way for me to check thrust.  Also, the addition of more rear camber seriously affected toe so I scheduled an appointment at Lutz Tire for an alignment.

The front camber and caster are both maxed out already so nothing to do there until new caster plates or custom strut mounts are available.  I was expecting more camber and less caster, but overall I am pleasantly surprised with the front settings at this time.  Ultimate plan is to have much more caster than camber to keep the tire upright and help put power down and a lower ride height can keep body roll to a minimum resulting in less camber loss.  I asked for and prefer zero front toe.

The rear alignment is what caused the spooky handling last week.  The alignment printout does not show the true rear initial settings because we were playing with dynamic toe and forgot to save the 'before' settings.  Total toe was out at least .20 and thrust was way off to the left.  Dynamic toe was difficult to measure because the computer display was delayed and the stiff springs made it hard to steadily move the car much.  We could bounce the car but never got any firm reliable data.

Based on the initial toe settings I can be fairly certain that adding rear negative camber reduces toe (adds toe out).  I purposely set this rear camber after seeing pictures showing body lean and tire roll.  I believe some camber gain is lost with the lower ride height so the -3.4* may sound excessive but it keeps the tire square in the corner and under load.  My preference is to keep the tire happy and car predictable so I also added a little rear toe in.  Rear suspension bushings may have some dynamic deflection that change toe and these bushings are on my 'to do' list.

Is the car better or less spooky?  Yes.

San Diego SCCA hosts an autox at Qualcomm January 25th and with my fresh alignment I show up early and prep the car.  Only other change is to soften the rear swaybar from 3/3 to 2/3.  STF is first run group again with sunny skies but cool air and cold slick asphalt. Cold RS3 tires do not work very well and it takes me a couple runs to build up my confidence.  Tire pressure 44F, 26R Handling is fantastic after the tires build heat and throttle rotation is smooth and easily modulated.  Wheelspin is a constant issue but easy enough to drive through.  Transitions are a little lazy.





The only problem is again the rear swaybar.  Some lateral movement has the bar shifted to the right and now hits the outer portion of the lower control arm.  Some clamping collars should keep the bar centered and avoid contact.  I also ordered some longer endlinks that will rotate the arms up and allow more clearance to the LCA.  The exhaust pipe is still resting on the swaybar and will get modified after final swaybar position is finalized.

And the banging noise from last event is coming from the exhaust midpipe knocking on the floor.  To go along with the other three Mugen motor mounts, I have a new Vibratechnics rear motor mount on order which should reduce or nearly eliminate engine rocking.

Scrambling

A whole bunch of changes and new parts installed since the last autox nearly 6 weeks ago.  CalClub runs this autox on the low grip asphalt parking lot outside AutoClub Speedway.  Weather was sunny and mild. I ran first run group PAX class and the course is very simple with several sweepers and straights and a slalom or two.

The new bucket seat suits me well and gives me much needed headroom.  Comfortable for the 3+ hour round trip to Fontana and back.  Cruise control lets me move around a little and stretch my legs.

Power has made a big jump with the addition of the KPro ECU, header, and exhaust.  Currently only using the "stock" Hondata tune which lowers the vtec engagement point and increases the rpm limiter to 8600.  More power is available with a proper dyno tune.

The smaller front EM2 swaybar has shifted the balance just enough to get my attention, but with so many other changes at the same time I cannot be sure what to think yet.

The rear swaybar, now correct side up, does not interfere with the control arms at this ride height, but still rubs on the exhaust pipe.  I have detected some side-to-side bar movement.

Dialed in more negative rear camber with the upper adjustable camber arms which may or may not have messed up my rear toe.

The biggest change for this event was the 15" Rota wheels and Hankook tires.  The front wheel balancing weights interfered with the brake caliper so I peeled them off.  No other clearance issues. Mostly due to limited availability, I am using different sized tires front and rear; 225/45 front tires and 195/50 rear tires.  My thinking is that the wider front tires will help put power down to the ground and the shorter and smaller rear tires will lower the rear COG, increase front caster, and build heat faster. Set air pressures to 44 front and 27 rear.  No ABS interference or problems with the half inch diameter difference front to rear.  Gearing is good for about 62 mph in second gear.

On course the car was a little challenging.  Corner entry was very loose for the first few corners but the car seemed to settle down on the back half of the course.  I am guessing cold rear tires are the problem. Mid-corner throttle lift seemed to be too sensitive and breakaway characteristics were not smooth or predictable.  Again, cold rear tires may be partially to blame, but uncertain rear toe could exhibit the sketchy feeling I was getting. Corner exit was all about straightening the steering wheel as soon as possible so the front tires could hook up.

Results

Video

The only problem I had with the car was an occasional banging noise coming from the bottom of the car.  With the increased gearing, power, and grip, I think it may be wheel hop or engine movement related.  The front swaybar is just a couple millimeters away from the header and the rear motor mount is still the oem piece.

Power is Everything - Part 2

Wow, just wow.

Start '15

Shopping for a race seat could not come soon enough as my tall torso and stock seats pushed my helmeted head sideways into the sunroof area causing a sore neck and shoulder at the last autox.

For the driver side I chose to go with a Buddy Club adjustable seat bracket because the design mounts the seat low and it works well with most all popular side mount bucket seats.  Price was very reasonable which gave me concern about quality or fitment, but initial inspection showed good welds and sturdy 3/16' steel construction. Slides are tight and difficult to move, but smooth and double locking. I am sure they will free up a little with some use.  A tab is provided for the seatbelt buckle receiver, however the factory Acura SRS integrates a bulky and complicated auto-tensioner into the buckle receiver so it will be replaced by a simple unit from an Evo8.  Weight is 9.8 lbs. for the complete kit (one seat).

My previous Miatas all used older model bottom mount Momo Start seats and I was happy with their comfort, quality, and price so I purchased a newer side-mount Start for the RSX.  Probably due to safety certifications and design changes, the Start seats have gained weight over the years as this current seat weighs 19.3 lbs. Combine that with the Buddy Club rails and seatbelt receiver and the total is 30 pounds; five pounds over the minimum allowed weight but still a full 20 pounds less than the factory leather driver side seat which weighs 50 pounds even.

Rail mount and side bracket assembly onto the Momo seat was quick and easy and mounting the complete seat into the car was simple using the factory mounting holes and bolts.  Seating position is very low, but the side brackets give a huge range of adjustability in both height and recline.  At full forward there is some contact with the center console and about an inch or more clearance from the door panel at both the shoulder and leg.  Plenty of room rearward for long legged drivers.  As anticipated, the slides are stiff, but should get better.