Monday, December 16, 2019

Ultimate Air Station

In racing, tires are the single most important part of the car. If your tires aren't cooperating, none of the power, none of the suspension and none of the driver's inputs will be of much value. Finding the optimum inflation and keeping it consistent run after run is key. Learning a course within 3-6 runs, sometimes in changing temperatures or drying conditions is complicated enough. Throwing in variation due to tire pressures rising with tire heat or becoming un-even from tires baking in the sun during lunch only adds to the complexity.

Obviously having a good pressure gauge is key, but in my opinion, so is having a good tire inflation system. Many are the times when one finds oneself gridded up and in finding the sprayer, helmet, gopro battery etc, and  swapping tires, cleaning out the car putting on driving shoes, going through tech and trying to remember the course you just walked (or that you drove in the morning), one discovers... "oh crap I didn't air up the tires!" If you have one of the rinky-dink consumer inflators you now have to choose which tires to inflate how much and maybe take your first run under inflated. We don't get many runs to begin with, it really sucks to have a throw-away run.

The problem is that most inflators have been designed to a task and the cost of parts minimized. The task they are designed for is road side and parking lot or driveway tire inflation, usually of a single tire that has gone flat to facilitate limping to a service station, or for topping up your tires. In either case spending 20-40 seconds to add 1lb of pressure is perfectly fine. The under inflated tire will be good to go in 5 min...

At an autocross one wants to NOT spend time on airing, but rather spend time mentally preparing for the run. Typically 4 tires need to be inflated 2-4lbs each. so 8-16 lbs at 30sec/lb becomes 4-8 minutes... which is an eternity when the grid chief is already sending cars at the head of the line. Or in the morning when you want to get to the tech line, or when course is already open and you need to get out and walk it...etc. Time is valuable.

I realized this long ago when I went to my one and only track day and nearly missed the start of my session because I was adding air to my tires with a commodity inflator. The following winter (2008-2009) I cobbled together this unit:

What that is is a Viair 300p compressor and an autozone whatever battery pack bolted and tied to a piece of plywood. It's heavy, the cord tangles on nearly everything, it takes forever to charge, and has a couple of sharp screws sticking out where they can gouge apolstery and leggs, but adding 2-4 lbs of air to the tires on my car is about 15-30 seconds. each.

This has been my solution for 10 years and it's been very durable, very reliable if somewhat heavy and unwieldy. But alas I've found that the battery pack is now not holding very much charge at all. Other drawbacks include an on-going risk that the clamps that connect the compressor and the battery pack are live 12v leads exposed where short circuit could be a problem. This poses an on-going risk during transport if the battery master switch is not attended to, and is just downright risky at rain events.  It's been good, but now I've found better.

As the trend toward more and more powerful battery operated tools continues, small cordless air compressors have come out and currently there are 3 on the market, One by Dewalt, one by Rigid, and one by Royobi. They all feature a small tank, lithum batteries and standard 1/4 air hose couplings.  The Dewalt unit sells for $300 with one 60v 2ah battery (6ah printed on the battery is only if it's in 20v mode). It's bigger more capable, and too heavy. Overkill for my use case. The Rigid unit is a 1gal tank and correspondingly smaller, but it sells for $250 with NO BATTERY. However, the Royobi unit without battery and with and included air nailer, hose and tire chuck is $129, or $99 by itself. With battery and charger, it's $179. It's also the smallest and as shown above comes with a very convenient storage for the hose.

It fills itself in 1-2 minutes and then stands ready. How fast is it at filling tires? When I got it I checked the inflation on my F150, and realized that the cold weather had me down almost 5lbs. Also the newly installed snow tires on my wife's camry were down a similar amount from sitting in storage. I topped up all 8 tires on about a half a 4ah battery. So one battery appears to easily provide 80lbs of pressure going into a 25-30 psi tire standard size vehicle tire. I set the output pressure to 90psi and the time to put 5lbs into my truck tire was 18 sec.

The pump comes on after about 2.5-3lbs added to the truck tire, so I suspect adding more than 5lbs at a time would get a lot slower. I suspect the pump on it is somewhat less than the Viair pump, but it has the opportunity to do work while you are moving between tires, so it's a very efficient design for topping up tires, which is exactly my use case.

The Dewalt unit is probably the winner for contractors with the larger tank, and better price than Rigid. The winner for autocross however is clearly Royobi on cost, size and accessories.

Note: I am not sponsored by any of these companies, and all of them are about to be completely blindsided by my review :). Prices for Rigid/Dewalt taken from Amazon on 12/16/2019, Price for Royobi from Home Depot (actual purchase: $129 kit with nailer/chuck and 2 4ah batteries on sale almost 2 for 1 price = $208 total before tax). I did not purchase or test the other units, analysis (and my buying decision) was based on features listed on the above mentioned sites. Royobi unit also was in stock at my local store, and available same day vs ~ 1-2 wk shipping for other units.

Friday, November 29, 2019


The guy who tunes my car was at SEMA recently, promoting the ECU's I use. Looks like EMtron's been making a splash in time attack. Here's  the video:

Thursday, September 19, 2019

Just for Fun

I remembered these videos again and suddenly wanted to watch them. I had to spend several minutes searching the series of inter tubes until I found them. They are classics (in my mind at least) so to avoid having to searching for them again I'll share them with all of you. (I did not make these, credit goes to the owners on YouTube!) Please go like/subscribe there!

And I'm sure you can guess how that turned out... but wait you don't have to! Here's part 2

He said drive flat out? That sounds familliar... Ah now I understand! his dad is into track days... he's famous too!

Monday, August 19, 2019

2019 Reboot

Totally shirked the blog last year and most of this year. Last season (2018) was actually a winning season though! That's 2 jackets now, and this time I had some more serious competition. My end of season however was less inspiring than some others... I clinched the title in August, and then proceeded to not win again, and for whatever reason I couldn't seem to stop hitting mystery cones in the Moss... so I wound up standing on a stupid slow run and didn't even try to match it in the afternoon, but rather just drove faster (I found 2 seconds vs the morning time which tells you how bad my morning was)... Although that catapulted me into last place in the moss with an epic bad consistency score, it turned out to be a good call since it was fun and 2018's moss featured the single most epic battle of moss competition I have ever seen. Nothing I could have done aside from repeating my times to the thousandth would have even come close.

First and second place were on an entirely different planet from the rest of the field. They both scored over 199 points out of 200 and were separated by some crazy small fraction of a point. The winner, Brian Kuehl put up a top pax time, and then duplicated it 3 more times in the afternoon to within 0.1s... absolutely nuts! for the speed/consistency challenge that is the moss that is AMAZING... and it almost wasn't good enough, because second place was just as consistent, but 2nd in pax by 0.088 seconds! On *ANY* other year Ryan Field would have been a champion with his 199.3 points... (winners normally have 196-198 points). If there were ever a case for co-champions this would be it, but that just isn't how it works.

So then winter set in, and as usual, not much happened with the car other than an oil change until after Christmas. Then in January, the prep for 2019 began...

  • Oil Change
  • Pads and rotors
  • Transmission Oil change
  • Front ball joints
    • Upper changed to pre-load adjustables
    • Lower changed to drop joints to enable lowering
  • Front wishbone bushings - apply the other half of the set of monoballs 
  • Penske double adjustable shocks
  • Custom carbon fiber wind splitter
  • Carbon fiber front lip.
  • Fabricated carbon fiber spats for the splitter 
  • Design/build detachable mounting system for splitter/lip combo
  • Check Alignment
    • Toe: front 0mm rear 2mm
    • Camber: just check for more than 0.2 degrees diff side to side, max otherwise
    • Caster: TBD, but so long as it's stockish and not wildly diff side to side I won't touch it because it's a royal pain to adjust.
  • Shorter Rear springs to prevent clash with body when lowering
  • Lower to 105mm rear 92mm front
  • Corner Balance
I got all that done, and after a little on-site fender modification during the test/tune, First event went well, and I managed a 0.95 pax Ratio vs a Billy Davis top pax and .96 vs the rest of the field. Event 2 however didn't go as well...

My ring and pinion was wrung and piƱata-ed. Thus events 3-7 and the NY tour featured me in a variety of fun STS and ASP cars, which were excellent cars, but definitely required some adjustment in style... Many thanks to Matt, Jake and Brian for their support during the repair period!

So the transmission went on vacation for a spa at Blackwatch Racing, where it ditched it's old and busted parts and acquired some new hotness... a 4.8:1 final drive ring/pinion set by Kaz. 

No point in not upgrading once it's all apart and the old part failed anyway... So hopefully the higher quality of the Kaz part will allow for some enhanced durability, and the shorter gearing will bring me up to speed a bit faster.

Got the transmission back and I had taken the clutch off to check it (since the trans was off and it was exposed), and when I initially re-assembled it, I put it on backwards. Unfortunately attempting to screw down the pressure plate then bent the clutch, so new clutch... and new friction surface for the flywheel. This mistake may have been a boon however since the friction surface though still thick seemed to have some dodgy looking warping and heat marks after I removed it from the flywheel...

So, waiting for new clutch and new flywheel surface delayed install and Friday afternoon before the race on Sunday I was still re-installing my fly wheel. A 4pm Friday through midnight Saturday effort got the fly/clutch/transmission all re-installed and all the parts put back on the car... which included starter, clutch slave, 3 out of 4 motor mounts, both axels, the entire left rear suspension, left rear brake, a couple bits of the right rear suspension that had been detached to facilitate axle removal, the exhaust header, the CAI (removed for access reasons), the gear shift linkage, the muffler, the rear clam, etc. 

Somehow I hadn't lost anything during the intervening 3 months and nothing went wrong other than tearing the oil pan heat sensor wire out due to motor sway while torquing flywheel bolts. That only attaches to an aftermarket gauge in the cabin, so not a show stopper. 

Shower and bed by 1am, up at 5am, to load the truck and on site by 7:45 am... And to my utter amazement, nothing actually fell apart or broke. The car had survived and performed well. My driving... well... I'm going to have to get used to driving an SSM lotus again. I had no clean runs but I did give Nik the opportunity to snap this awesome shot: