April 2017

Two More Events

We had events two and three on Saturday 4/1 & Sunday 4/2.  Saturday, rain was inbound. I went out fast on run 1 and had one bobble, but it was good enough to put me in first.  On run 2 the rain had started, but the pavement was still pretty dry.  I really let it hang out.  I had one small mistake at the turn around and was coming home fast....too fast. I punched the cone before the finish gate. I tried tapping the brake and as we know my pedal sucks.  Run 2 was still faster even with the cone.  Pulling into grid, the sky opened up. Run 3 was a slippery shit show.

Sunday was dry. Not much drama to speak of.  Swapped the lead twice.  My top competitor's co-driver went out for run three and snapped the left rear axle after launch.  They managed to replace it in the span of one run, but I think it just broke their rhythm and they lost what little heat they had in their tires.  Still, Kudos to them on the quick fix.
I munched three cones on my last run Sunday and brought them all back under the car. Need to check for damage underneath.  In spite of putting on gloves to get them out, I still burned the holy crap out of my right wrist getting one of them free.  Run 5, a fun run, turned out to be my best of the day.

Three outings and three firsts, not too shabby vs. 9 drivers at event 1 and 7 at events 2&3.  We have one more PIR event before we move on to the big tarmac at Packwood.

Long Break

We have no May event, So I have a long break for some fine tuning. I'm learning my brakes are actually working ok for what they are, I just can't live with this shit pedal.

• I've got the NB Master cylinder and brake booster on stby in the garage.  
• I'll go over the car and check for loose parts.  
• My weak ass front air dam support broke the first time I sucked up a cone.
• Left front flare broke loose from the bumper. Rivnuts don't work so great in plastic.

Brake Upgrades

If you've been reading my blog, it's no secret that I'm not pleased with my pedal feel and stopping power. As an NB Sport driver, I'm use to a high hard pedal.  In addition to the naturally long throw and soft feel of the NA ABS pedal, I think my master has some internal leakage.
I decided the best route to fix my pedal was to upgrade to an NB ABS master and booster, $80 shipped from eBay.  So, whats the difference.
96 NA ABS - 7/8" master with 4.74:1 booster - yields ~775 psig for 44 lbf pedal pressure.
01 NB Sport ABS - 15/16" master with 9.7:1 booster  - yields ~1038 psig for 44 lbf pedal pressure.
That's about a 25% increase in line pressure for the same effort.  Additionally, the 15/16" master should give a much shorter throw since more volume is moved per lbf applied at the pedal.
I expected this job to be a pain in the ass, particularly the line bending and post bleeding.  It actually went fairly smoothly.
First, I put a ton of plastic and paper towels in the work area and over the fender.  I don't want any brake fluid in contact with my paint.
I removed the old master, booster, and proportioning valve as a unit. Super simple, no problems.  I'm keeping the 96 prop valve.  I'm not convinced I have a bias issue and since my actual brake hardware isn't changing, I want proportioning to stay the same.

I bought some 3/8" vinyl caps which I lined with some paper shop towel. When I opened the flares, I put the caps on immediately. They're nice and tight. I lost maybe a drop on each line, maybe.

I transferred everything to the work bench.  I leaked a holy shit mess of fluid on the bench during the job, oh well, not on the car at least.  Next I transferred the 96 prop valve and bracket onto the NB master/booster combo.
I decided to go with pre-cut and flared lines.  After some research, Poly Armor seemed to be the best choice.  Autozone carries these in various lengths. They're easily hand formable. I bought two 12" and one 20" for contingency.

The lines were easier to form and line up than expected.  I did a vertical drop to a 90 off the prop valve and a somewhat steady curve up to the master. The 12" lines proved to be adequate.  I'll return the 20" and get my $6 back.
The next step is to bleed the master.  I decided to bleed the master, new lines and prop valve as one unit.  I pulled the master and prop valve off the booster, bolted them together with some spare bolts, and put it in the vice.
No photo, but the first bleed step was to get fluid through the system.  I attached the bleed nipples to the prop valve outlets, filled the master, and forced two full cylinders out to a catch can using the power bleeder.
Now it's time to bleed the master.  I directed the prop valve outlets back the the master reservoir and started hand pumping the master.  You don't want to go full stroke or you may damage the master seals.  I used my hand with a leather glove to pump the master limiting it to about 3/4 stroke.  I gave myself a rule of 20 pumps with no bubbles to be done.  The master bleed takes time and patience.  It took over 300 strokes before I was confident that there was zero air in the master.  Do yourself a favor, get every drop of air out.  If you send air down line to the ABS pump, you'll be crying in a couple of hours.  Here's the master bleed setup.  Dorman makes a bleed kit with various nipples, but they only have one of each nipple, so you have to buy two kits, go figure. I used my own hose since the hose they provide is opaque, why?

When the master was fully bled, I topped it off and put some rubber caps on the nipples. 

My pedal height and adjustment before work was known good.  I wanted to just drop in the new unit, so I carefully measured the pedal linkage length from the booster face to the pedal pin on the 96 booster and matched the NB booster to the 96 to within <1mm.  Installation in the car is simply the reverse of removal.  

Time to bleed/flush the car. I hate pumping the power bleeder pressure tank up constantly.  I got the idea to use a regulated air source. My leak down tester turned out to be the perfect tool.  I just added a male pneumatic fitting to the bleeder cap adapter, perfection.  Occasionally my phone turns all the reds in a photo into a crazy green, pretty wild.

I expected there to be a lot of air, there wasn't.  I bled two full cylinders of DOT4 to each corner cycling the ABS pump in between.  Here's the finished product with all the gunk cleaned up.

My pedal is rock hard with no drift down over time.  I'm waiting on a new vacuum check valve hose for the booster.  The NA hose is too short. I'm excited to see how the pedal feels under boost.  If my brakes are still weak, my next step is to upgrade the rears to sports.  Hopefully it won't be necessary.  If I have bias issues, I'll try fixing those with different pad combos.  The total cost including bleed kits & fluid is <$150.  If it works, it'll be some of the best money I've spent.

Post Race Inspection

I went over the entire car and fixed some issues.
My tail pipe keeps edging left until it rubs against my tie down support.  The vibration noise it makes is hideous.  I worked the exhaust as far right in the hangers as I could and then put some small hose clamps around the hangers to hold it where I put it. Hopefully this will hold.
My power steering reservoir has overflowed a couple of times.  Level still indicates good.  I think this issue will self correct.
I marked all my alignment bolts when I got home from the alignment.  Everything was good post race except both front forward lower bolts slipped a ton.  I found both of these to be extremely loose.  I sincerely hope they were tight when I drove off the rack or my marks might even be wrong.  I doubt they were loose.  My shop has never done me wrong.  I put the bolts back to my marks and tightened the living hell out of them.  I similarly tightened the remaining bolts.
Rivnuts don't work so well in plastic.  My right front flare popped free when I hit a cone.  I decided to hold that in place with a small zip tie for now.
For some reason my brake booster vacuum hose order from Mazda Motorsport is errored and never shipped, so I haven't been able to re-test my brakes under boost.

Brake Check & Rain Tire Option

My new booster vacuum hose from Mazda arrived with a stuck check valve. I shoehorned in the 96 hose for a test. I made a couple of driveway pulls, holy crap!  My pedal feels amazing.  I can now invoke ABS  on the 205s.  I doubt I'll invoke ABS with the Avons, but now I can have some confidence in my brakes.  I'm telling you, flying into a corner with the previous pedal feel was not good. The fear was real.  This mod is amazing!
I also managed to fit my E-Street wheels with 205 RE71Rs onto the car. My previous issue was finding some workable open tuner lug nuts to work with extended wheel studs.  Turns out Gorilla makes a descent set.  Now I at least have a full wet option.