Tire Pressure Woes – Autocross Tuning Tips

Steven Johnson is a serious autocrosser.  He has learned much as an HPDE (High Performance Driver Education event) participant.  He also serves as the coordinator of the Harris Hill Road Chrono-X Time Trial Series.  In addition, Steven is looking for a different career direction.

In the meantime, he asked me if he could share his knowledge & observations with the Racing Ready community.  Knowing how thorough a competitor & helpful instructor Steven is, I did not hesitate to welcome him as Racing Ready’s newest guest blogger.

Here is his first entry…thanks Steven!

Steven's 350Z at SPOKES autocross @ SAR in July 2008

Anyone who tells you that tire pressures are not important has obviously never seen the limits of their own car.  When I first started autocross, I would simply add pressure and hope for the best.  How naive was I?  As I found out at the last SPOKES/SASCA autocross, tire pressures can mean the difference between a smooth run and absolute chaos!  My rear pressure used to be too low, giving me too much rollover.  Then I tried too much pressure and the car was drifting all over the place.  It was so bad that I wasted 3 runs just because I added 5 psi.  After that day, I learned to respect the pressure of your tires.

Steven's 350Z at SPOKES autocross @ SAR in 11/2008

I run a set of Dunlop Direzza Starspec Z1s in the STR class. The class allows for a 140 treadwear with a 255 width maximum.  Unfortunately, the Starspecs are not considered the best tire for the class.  The Toyo R1-R at a 140 treadwear seems to be the tire of choice (Car Tyres).  So why did I choose the Dunlop?  Is it because I like a challenge?  Maybe because I enjoy loosing?  No, the reason is because the autocross gods frown upon heavy cars like my 350Z.  My car requires a larger and taller tire than the Miata’s, Mr2’s, and S2000’s.

Steven's 350Z ready to compete at SPOKES autocross @ SAR in 11/2008

Simply put:

  • The Toyo R1-R is better in a smaller, shorter tire
  • The Dunlop Direzza is better in a larger, taller tire

So while smaller cars can run the best tire in the class, I am forced to use the underdog Direzza.  That being said, I love these tires!  They stick great and heat up quickly.  In fact, if you ask some drivers they will tell you that treadwear doesn’t  tell the whole story.  They will tell you that the Direzza is just as good, if not better, than the R1-R and it depends on the course conditions.  For instance, the Direzza is said to have a little bit better dry course handling.  In the rain, the R1-R cannot be touched.  So which tire should you choose? Don’t ask me, ask your car.  How heavy is it, what tire size does it need, and what type of driving do you plan on doing?

Steven @ speed (picture courtesy of Jerry C, my autocross mentor)!

Back to tire pressure:
What difference can a couple of psi make?  More than you would think! I used to just guess at what was right and put in around 28-30 psi front and rear.  I would just go out with whatever handling characteristics it gave me and deal with it.  Then if the pressure jumped up a few pounds (which it will if you drive right) I would bleed off enough to get back to where I started. This is the WRONG way to setup a car’s tire pressures.  I asked around and found out a few key tips to setting tire pressure:

  1. You can use tire pressure to actually add or subtract traction in front or rear
  2. More pressure = less traction  Less pressure = more power can be transferred
  3. Finding the right balance between front and rear makes a huge difference
  4. You can induce understeer just by having more pressure in the front than in the back
  5. Don’t be afraid to have a 10 psi spread to find out what works.

I found out that my front tires actually worked best if the tire pressures were pumped up very high to around 38-40 psi.  My rear tires at that pressure couldn’t get traction AT ALL!  I ended up with the rear pressure at 32-33 which gave me the balance I was looking for.  I thought that there was some rule out there that said don’t let your pressure be over 5 psi different from front to rear.  As tip #5 above states:  Don’t be afraid to have a dramatic difference from front to rear.  It can teach you a lot if you are not afraid to try out extremes.

Slime - White Tire Marker from AutoZone

Marking your tires is a great way to gauge what pressures to use.  I use a Slime tire marker from AutoZone (see picture above).

Marked tire sidewalls on Steven's Drag brand wheels w/distinctive red stripe

Make three marks equidistant on the outside of the tire.  If you look closely at your tires, you will find a small triangle shape at the edge of the tread.  This is to help you in finding your perfect pressure, so use the tire marker here. You should mark your tire next to these triangles from the top of the tread down to the sidewall.

Tire sidewall triangle mark - click to enlarge, to better see the triangle...

After your run, the marker will rub off to a certain place.  You want the marker to be rubbed off at the tip of the triangle for optimum pressure.  If there is still markings above the triangle, your pressure is too high.  If the markings are rubbed off past the tip of the triangle, your pressure is too low.  You are looking for the maximum usage of tread without rolling over into the side wall.

I could go on all day about tire pressure, but you won’t know what works best for your car until you get out there and play with the extremes.  You will be happy you did.

Racing Ready welcomes Steven’s experience-driven, autocross tuning advice.  I look forward to future editions of this kind of well sorted out knowledge, in his easy to read conversational-style.  More to follow, down the road!

Dan

Autocross Knows No Age Limit For Leora!

Guest blogger Eric gives us a review of a new, young at heart autocross competitor!

One of the best things about autocrossing is the people involved.  I met Leora at last month’s SASCA autocross, where she was a spectator, and we got to chat about our mutual affinity for the Corvette.  This month, she participated in her C5 coupe.

Novice Leora's Corvette - front view from on the SASCA autocross grid

Aside from the custom paint and aftermarket wheels, the car features an intake, custom ground cam, ported heads, long tube headers and exhaust.  Inside, there’s a six-point rollbar, five-point safety harnesses, and a fire extinguisher mounted just in front of the passenger’s seat.

Leora's Corvette - following up the rear, in line at the SASCA autocross grid

I had the honor of being her novice rider, and from her first run to her second she improved a whopping 15 seconds.  Here’s a short video from the outside of one of her later runs, pardon the commentary (I believe Ricky was telling us a story about one of his rental car exploits).

An open road racing veteran, this was the seventy-year-old’s first autocross.  Hope to see you out there again Leora, and save the wave!

Racing Ready again thanks Eric for this blogged profile of Leora, SASCA’s newest senior autocrosser!

Dan

Formula 1 Grand Prix! Austin, Texas! For Real?

Today my personal e-mail Inbox blew up!  I received ALL sorts of Internet chatter & some interesting links about Formula 1 & Bernie Ecclestone, setting up for Formula 1 to race in the Austin, Texas environs.  The exact location is still not known, but many rumors are already afoot.  The contract is slated to run from 2012 to 2021.

2010 Formula 1 - a detailed visual overview

A few years back, there was word of a Formula 1 style track facility to be built somewhere west of Austin, to be called the Bergrennenring.  I recall reading something about that, but it seemed to have died in the vine.  The last post to their blog was in February, 2008.

Bergrennenring logo

This time round there is some major name dropping going on:

  • Bernie Ecclestone, the “grand poobah” of F1 himself is quoted
  • Rick Perry, the Governor of Texas, puts his promotional 2 cents in
  • Lee Leffingwell, the Mayor of Austin is rightly impressed

“This is a case of the right timing in the right place,” said Austin-based Tavo Hellmund, the managing partner of race promoter Full Throttle Productions, a special event and sports production company that was formed in 2005.

Based on all the Internet chatter, this is something so very many in the regional motorsports community are looking forward to.  Here’s the major article links I have found.  Go ahead, read them at your leisure:

Thanks to Monica, SPOKES member, here’s the one quote that sums all this up best!

Something being announced in Formula 1 doesn’t mean it’ll actually happen.

Racing Ready thought that IndyCar was the only professional series of world class open wheel racing, to be available nearby.  The next one is the Firestone 550K, at the Texas Motor Speedway.  This race takes place on June 5th, 2010.

Well, now we’ve a sense of world class racing hope!  This will make South/Central Texas more of an authentic motorsports activity hub.  We’ll see what develops…

Dan

SASCA 2010 Autocross #5, By Eric!

Once again, Eric steps up to the plate as Racing Ready‘s well-regarded guest blogger.  Here’s what he wrote & recorded – thanks Eric!

Yesterday was the running of the fifth SASCA autocross of the year, a co-event with SPOKES at the Blossom Athletic Center.  As with most co-events between the two clubs, there was a large turnout, with 127 paid entries.  Vivek was in charge of designing the course (as Eventmaster), and he managed to come up with a layout that was both fun and challenging.

Sunshine, Eric's 2001 Z06

We were up in the first run group, and due to an incident involving a cross threaded lug nut, Jay would be co-driving Sunshine, my 2001 Z06, in Super Stock.  He was smooth and consistent, eventually getting down to a 46.1, as in the video below.

Meanwhile, I was struggling to break into the 46s, squeaking in with a 46.9.  I was changing my braking points almost every run to no avail, and I wasn’t nearly as precise around the cones as I would’ve liked.  Until, finally, I hopped into the passenger seat, got schooled by Jay, and decided to combine some of the good points of his run with what I’d hoped were the good points of mine.  The following, a 45.5, was the result.  You can still see where I lost time, but it was much faster than before

Believe me when I say that some of the full throttle sections were nerve wracking thanks to Blossom’s bumps, but sometimes you just gotta trust in your car!

On the SASCA-SPOKES joint autocross grid

The joint SASCA-SPOKES grid axiously awaiting their next runs...

Moral of the story is, take every opportunity you get to learn something.  Thanks to Jay for being a great co-driver and letting your car owner get the win 😀 .  Though I’m still trying to figure out how Rick, driving the grey Z car below, managed a 43.7, which was good enough for TTOD by 1.2 seconds over his next nearest competitor.  I think the FP field in Lincoln (SCCA Nebraska Nationals competition) had better watch out.

TTOD Rick M's FP class Datsun - He's FAST with that car!

All in all, it was a great event, and much thanks to everyone who pitched in.  Maybe next time we can even get Dan himself to come out and race!

Racing Ready is SO appreciative of Eric stepping up to guest blog for me, in my absence of participation.  My current work schedule has me busy on weekends until July.  Thanks again, Eric!

I did show up for the last hour & here’s the best autocross “move” I accidentally caught on video…you GO Vivek!

Dan

Texdive Motorsports – Regional Racing’s Finest

Texas Super Racing Series - Allison Legacys

I met the principal members & drivers of the Texdive Motorsports Racing Team just the other day!  Peter Runco, Manager of Texdive, has been grooming his kids to go as far as they can, starting with karts & Kart Runco Racing.

Since then, Cole (alias Rowdy”, car #19) & Lauren (alias “La La”, car #56) have graduated to the Legacy Allison Spec Racer car.  They are competing in the Texas Super Racing Series (TSRS)/Allison Legacy – showcasing tomorrow’s racing stars!

Cole Runco - #19 TSRS Allison Legacy - Texdive Motorsports

Lauren Runco - #56 TSRS Allison Legacy - Texdive Motorsports

They race these 3/4-sized NASCAR racing cars in the TSRS Series.  This is a cool, surprisingly fast & maneuverable car powered by a Mazda 4 cylinder truck engine.  The engine is internally stock, but obviously everything outside is not.  The secret is in tuning the chassis.  Here are the specific details from the manufacturer:

The Allison Legacy car is a three-quarter sized replica of a Sprint Cup car and is powered by a four cylinder MAZDA B-2200 truck engine that produces approximately 125 horsepower.  The cars use the standard MAZDA five-speed transmission.

The cars weigh about 1,400 pounds dry but must weigh a minimum of 1,675 pounds with driver to race.  The series is a “SPEC” series designed to minimize your racing costs and place the emphasis on the driver instead of the equipment.

“The Allison Legacy Cars are excellent equipment for the beginner to get his or her first exposure to racing,” said David Pearson, winner of 105 NASCAR Winston Cup races.  “They are well designed and professionally constructed cars that will give the drivers the same feel and experience they would get from a bigger and more powerful car.”

The Allison Brothers, sons of former NASCAR competitor Donnie Allison, are the creators of the Allison Legacy car.  Rules and National technical inspections are strictly enforced to limit alterations to the basic car. The engines are sealed and can only be rebuilt through Allison Brothers Race Cars.  The engines are resealed before shipment back to the competitor.  Almost all parts are spec and cannot be modified for competition.

And here are the detailed specifications of this well sorted out race car:

*  Body Styles – Thunderbird or Monte Carlo
* Engine – Mazda B-2200 120 HP
* Weber Carburetor
* Fire Suppression System
* Aluminum Racing Radiator and Electric Radiator Fan
* 4.8 Gallon Fuel System
* Sealed Engine with 5 Speed Transmission with Reverse Gear
* Vehicle Wheel Base – 80 Inches
* Vehicle Width: 60 Inches
* Length: 12 Feet 6 Inches
* Height: 42 Inches
* Vehicle Weight: 1425 lbs (without driver)
* Tires – Goodyear
* Wheel Size – 13” x 7” Steel Racing Wheels
* Wheel Width: 7 Inches
* Wheel Diameter: 13 Inches
* Aluminum Front Hubs
* Interchangeable and Adjustable Front End Suspension
* Quick Change Rear End
* Fully Adjustable 3 Link Lear Suspension
* Rack and Pinion Steering
* One Set of 4.86 Gears
* Four Wheel Disc Brakes
* Coil Over Shocks and Springs
* Aluminum Racing Seat and 5 Point Safety Harness
* Custom Window Safety Net
* Custom Instrument Panel – Tachometer, Oil Pressure Gauge and Water Temperature Gauge

In the picture below,  of both Texdive Motorsports Allison Legacy race cars, you can see how small they really are…!

The Runco Allison Legacy Race Cars, prepping to load them in the trailer

Peter Runco is a proud Dad who really supports his kids, who are now becoming young adults (Cole is 18 & Lauren is 17).  In order to support the demands of racing they are pursuing, both Cole & Lauren are home schooled.  You see, the Runcos aren’t doing this as a hobby.  Years ago Pete saw his kids achieve better than average, consistent finishes in shifter karts.  He decided to move this from expensive hobby to a serious business, & developed Kart Runco & setup an almost mile long track in South/Central Texas.

Pete, his racer kids & the team he has built up are seriously committed to racing success.

Texdive Shop & Lot panorama

Since the end of last year Cole has won all races he has entered in the TSRS Series.  His sister Lauren has finished usually about 3rd or 4th.  But they recently found out her car wasn’t performing to its potential.  This was due due to some broken parts, not working properly on her car.

This is the Texdive Motorsports Allison Legacy #56 - it's a bit cramped in there!

Pete also mentioned that in a recent track test at their local track, Thunderhill Raceway, Lauren set a time just .04 seconds shy of the track record.  So, watch out big brother!

Just a portion of the Texdive Motorsports shop, with the #19 Allison Legacy car

You will see more coverage of this team as they have just signed up, with me, to be an Independent AMSOIL Dealer, into AMSOIL Racing!  This will be fun & interesting!

Feel The Thunder at Thunderhill Raceway - Kyle, Texas

Racing Ready is looking forward to learning more about this Regional NASCAR feeder series.  It will be great to be involved in Texdive Motorsport’s growth & racing success.

Dan

Miata Journal, Multi-Media Miata E-zine Debut

Miata Journal - M

Visiting Corky Bell’s website, BEGI (Bell Experimental Group), I found out about a new Miata e-zine (online web magazine) called Miata Journal.

Miata Journal 'Cover'

They had an incentive (3 free months) to advertise, so I decided jump onboard.  You too will want to jump on board & subscribe for free – Volume 1 has just been released!

Miata Journal - Ready To Rock

As to full disclosure, I’m an advertiser in the Miata Journal E-zine…on page 24!

Racing Ready on Miata Journal!

See below for a sample of the Miatae & article topics you can enjoy as a reader:

Miata Journal article samples

Racing Ready is trying this to see what results will happen…  So, spread the word, subscribe & click through to the various advertisers at the Miata Journal!

Dan

AMSOIL Show Booth Promotional Video

As I ramp up my AMSOIL business, I have been working a monthly local gun show booth.  My good friend & helpful AMSOIL sponsor, Mike Westwood, is generously assisting me.  Mike most definitely wants me to succeed.  He has been a greatly supportive mentor, as I get established.

AMSOIL Products Display

Mike is always up to date with computer technology peripherals.  In the process, he sells off his previous technology solutions to move on the next, more capable technology.  I was able to benefit from this by receiving a Sony Webbie HD Digital Video Camera from Mike!

SONY Webbie HD MHS-CM1, in Orange

At the show I was able to learn the camera’s basic functionality & record a short video. Since we had our booth set up, I felt it appropriate that my first digital video promote our AMSOIL presence.  Mike is all about promotion & he greatly supports my blogging efforts.  Here is the video, after some basic editing in Windows Movie Maker:

To prepare myself for regular video contributions, I need to do 2 things:

  1. Purchase a SONY Memory stick (internal memory, obviously the onboard, internal memory isn’t going to cut it)
  2. Retrofit some sort of stable attachment point for the camera to mount on Karlino – should be a fun mini-project…

Car tripod mount...

Racing Ready needs to add more video content to this blog.  Having this little SONY Webbie will greatly help in this regard (it’s orange like a traffic cone).  I look forward to more of this…

Dan