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Colin Wood
Colin Wood Associate Editor
5/14/24 10:00 a.m.
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Good news: The One Lap CRX survived the 2024 Tire Rack One Lap of America Presented by Grassroots Motorsports.

Better news: The One Lap CRX finished first in its class and 11th overall in a field populated with heavy hitters like Turbo Porsche 911s, Tesla Model Plaids and ZL1 Camaros.

[An 11…

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Andy Hollis
Andy Hollis
5/14/24 11:13 a.m.

Greetings, and welcome to the post-mortem.  As grim as that sounds, all good race engineers do what's called a "set down" after every race.  Pretty much the opposite of set-up.

 Contrary to popular belief, a car does not usually come off the track in the same state it went on. Add in some 3500 miles on some of the "best" highways in the US (I'm looking at you, Indiana), and things get beat up pretty quickly.

 

Andy Hollis
Andy Hollis
5/14/24 11:21 a.m.

Being "that tire guy", the first thing I check out is our tires.  
 

Given sizing availability constraints, we were forced into a fairly aggressive tire choice, the Yokohama ADVAN A052.  At least we were able to make a larger size fit (225/50-15), so that gave us some sidewall relief over bumps and expansion joints.  
 

But, in order to combat accelerated wear, we pumped them up to 40 psi hot for transits. That mitigated the usual shoulder wear these exhibit on track.  We might have gone a touch too far on that idea, though.
 

Here's one of our rears, sporting less tread in the middle than the outer grooves...just over 2/32 vs over 3/33.  Most of this wear came from early in the week when these were on the front. We rotated F-R mid week at NCM
 

Andy Hollis
Andy Hollis
5/14/24 11:26 a.m.

With rain moving in for many of the track sessions and transits during the second half of the week after our rotation, the fronts have much less wear than the rears.  Easily 3-4/32 across the face.  Note that these start out at 7/32, so that's half tread depth.

We were also raising the ride hight 1" at the front for all of the transits, we takes out a degree of camber and moves the toe from our track setting of slightly out to slightly in.  This was successul in giving us more even wear, as the A052 like to wear the shoulders, especially the inside under heavy braking.

 

Andy Hollis
Andy Hollis
5/14/24 11:36 a.m.

One other wear note on the rears is the heavy inside camber wear shown here.  
 

We run a LOT of rear camber on track -- 4 degrees.  This actually delivers even wear when the tire is constantly loaded.  But for transits, it focuses load in a very small area.  
 

Our original plan was to mitigate this both with higher pressures on transits (which worked) but also to raise the ride height 1" at all four corners.  
 

But in an attempt to streamline the transit setup conversion process to save valuable time, we skipped that process for the rear after the first couple of transits.  Had it remained dry all week, that may have bit us with a corded tire. 
 

Andy Hollis
Andy Hollis
5/14/24 12:16 p.m.

Moving on to brakes, the situation is not nearly as rosy.  Leaks, boiled fluid, and accelerated pad wear top the list of challenges we faced.
 

We've been running this Fastbrakes kit since the car was first built 14 years ago.  Using Wilwood parts, it combines an 11.75x.81 curved vent Spec 37 rotor ring with an aluminum hat.  Basically, the largest you can fit inside of our 6UL wheels.

Calipers are the classic Dynalite 4-pot.  Without differential piston bores, the pads do taper.  But this was easily mitigated by flipping them every day when the wheels were off to adjust ride height. 
 

Wilwood provided fresh calipers with their trick Therm-lock pistons that keep heat away from the piston seals.
 

Early in the week, we started to see fluid seeping in the vicinity of the bleeders and onto our wheels and tire sidewalls.  Each time, we went in and tightened the bleeders some more.

The issue was not the bleeder itself but the adapter that threads into the caliper.  Once we'd get one to stop leaking, the issue would move to another in a never-ending game of whack-a-mole.

By the end of the week, we still had one leaking even with a LOT of torque on it.  We survived by topping off the master cylinder each session.

We did carry a fresh spare caliper, but it's always a risk when you open up the brake hydraulic system. 

Note: Wilwood no longer markets these calipers and encouraged us to update to the newer DynaPro design, but with limited prep time we decided to go with what we knew.

Andy Hollis
Andy Hollis
5/14/24 12:37 p.m.

For track sessions, we ran Hawk DTC-80...their most aggressive pad.  Mid-week, after the brake-intensive Hedge Hollow, we swapped to a fresh set.  
 

Our first set was nearly half worn and were grooving the rotors badly. These pads are very small, so there's not a lot of friction material.  

"Asking little parts to do big things"

 

Andy Hollis
Andy Hollis
5/14/24 12:50 p.m.

The other change in plan we made was transit pads.  For the first one, 11 hours, we ran Hawk HP+ street pads.  These smoothly removed the DTC80 transfer layer, which then had to be reapplied during the out lap of the next day's first session.  
 

That turned out to be harder to execute especially on wet mornings.  So we abandoned that plan, opting instead to run our track pads on the street.  Eventually, this caught up to us with braking shudders but it was after the final track session.  
 

The problem with track pads on the street is they do not evenly remove or add to the transfer layer as they are way outside of their temp range.

Once home, we used a set of old school, high metal content Hawk Blues to fully scrape/clean off that uneven layer from our rotors.  Works a treat. 
 


 

Andy Hollis
Andy Hollis
5/14/24 2:46 p.m.

Hedge Hollow is where the brakes really became an issue.  Tom went out first that day, and there was significant brake fluid coming out of yet another bleeder adapter fitting.   We cinched that one down and refilled the master for my session.  
 

Nearing the end of my afternoon session, the pedal started to go long.  Just as I took the checker and tried to brake for Turn 1, the pedal went to the floor. Pumping got some back and I took that turn VERY wide using all of the paved runoff.  The in lap was full of brake pumping to get back.

Once back in the garage,  we did our usual routine to ready for the transit.  Again, I cranked down on the offending bleeder.  Once cool, the pedal was back solid so we left for NCM.  
 

-------

Did the fluid boil?  It was brand new Castrol SRF, so not likely but?

Given that the pedal came back we never bled it all week ("if it's not broken, don't fix it").

Curious, I did a quick bleed once home.  All fluid, no air bubbles. 
 

Andy Hollis
Andy Hollis
5/14/24 2:52 p.m.

Upshot of the whole brake thing is that we added a lot more grip capability due to the new aero, which also changed the airflow around the rotor because of the splitter tunnels.  So while we gained a ton of grip, which the brakes could then use, we also created a new problem...more heat & less cooling.  Yay race cars.

So we'll be upgrading our braking system soon.  There are now new wheels available that allow for more clearance (Clarence), and NA/NB Miatas can now fit 11.75x1.25 rotors, which cool way better.  If a Miata can fit it, we can too.  So that's our next braking move.  We'll be needing different pads, too.

Tig
Tig New Reader
5/14/24 3:19 p.m.

So, I had similar terrible experiences with the old Wilwood dynalites, including different iterations of them (another platform). Endless seeping and weeping even with new fittings into which the small bleeders thread, including 1 catastrophic failure, which was ultimately attributed to a flaw in the caliper itself (early ones were cast, later forged billet supposedly). Anyhow, I bit the bullet and went to AP (all round) and never looked back...forgot about the brakes. 
Congrats on the class win and overall placement!!

Andy Hollis
Andy Hollis
5/14/24 3:38 p.m.

Oh yeah...rear brakes.  Almost forgot about them, since they don't really do much on this platform.

As expected, minimal wear on the shoes.  I did adjust them up about one full turn on the adjuster.

 If the rear brakes are not properly adjusted, there is a dead zone when you push the pedal...the rear cylinder has to move the shoes to the contact point before any movement happens to the front brakes.  And the OE auto-adjuster doesn't really work.
 

You can tell when they are right if the e brake only goes one click. 
 

Andy Hollis
Andy Hollis
5/14/24 3:44 p.m.

Next up suspension.  Camber and toe were exactly as expected.  There's a fair bit of play in the radius arm bearings, especially the left side.  This will make the toe vary a bit between loaded and unloaded.  But it's not all that bad just yet.

 

Also found some play in the LR wheel bearing, plus a little bit of noise.  Again, not so bad that it needs replacement, but needs to be watched,

Andy Hollis
Andy Hollis
5/14/24 3:59 p.m.
Tig said:

So, I had similar terrible experiences with the old Wilwood dynalites, including different iterations of them (another platform). Endless seeping and weeping even with new fittings into which the small bleeders thread, including 1 catastrophic failure, which was ultimately attributed to a flaw in the caliper itself (early ones were cast, later forged billet supposedly). Anyhow, I bit the bullet and went to AP (all round) and never looked back...forgot about the brakes. 
Congrats on the class win and overall placement!!

We've had good success with these over the years.  And the fact that Summit stocks them at a very low prices simply makes them consumables. 

But something has changed.  I noticed that the bleeder adapter is no longer a brass fitting.  Appears to be anodized aluminum.  It's also smaller now.   I had this problem with one other caliper before, but never this bad.

Andy Hollis
Andy Hollis
5/14/24 5:00 p.m.

Raised the car all the way on the lift and went over the whole underside.  No major issues.  
 

In the past, we've battled subframe cracking issues when the big motor went in. 
 

Here's some of Dr Frankestein's earlier work.

Andy Hollis
Andy Hollis
5/14/24 5:02 p.m.

This guy now needs a rebuild for sure.  Rapping on it, you can hear the perforated core rattling around.

Ran out of time to do it before the event. Those button head cap screws almost always get seized, so you have to budget time to extract them.  
 

rdcyclist
rdcyclist HalfDork
5/14/24 6:03 p.m.

Congrats on an Epic Showing amongst the Big Dogs of SSGT and then some. I have a coupla questions:

1. How did the 1L/CRX stay in Economy with the big ass engine swap along with big ass brakes and big ass wheels and tyres? Wouldn't that put it into some modified class? Did staying with a Honda engine keep it in class?

2. How did David manage to slay most of the Goliaths? I mean, E36 M3, you guys beat a ZL-1 Camaro being driven by a former PRO driver with a coupla rocks and a sling! That's berkeleyin' Amazing! And ended up about 28467 points ahead of second in class; apparently the rest of the Economy class brought a knife to the gunfight.

Besides all that, the transits were ... challenging. I think what Sam Smith wrote in his driving impression of the Shelby Daytona Coupe applies here: "If you sat down and designed a machine to make someone not want to do 180 mph in rainy race traffic at night, it would look an awful lot like this. Maybe more comfortable." The CRX was probably about like that...

Again, I stand in awe of your incredible performance.

Keith Tanner
Keith Tanner MegaDork
5/14/24 6:12 p.m.

This is great stuff.

About the brakes - if you're running lug mount Dynalites (I think you are) then the Dynapro 6A should be a straight bolt on. Same cross section for the same wheel clearance, differential bores with 6 pistons, much bigger pads. They're a PITA to change pads on, though, you have to pull the caliper off the upright. Only two bolts, but not bolts you really want to be screwing with on a regular basis. 

Consider the Performance Friction PFC97 pad. It's what I ran in the Targa Newfoundland, and it'll stop in a hurricane and on a hard track day in the high altitude desert heat - BTDT. They'll destroy rotors if they're outside their ideal heat zone, but they'll always stop. No need to swap pads  and rebed in that case. The rotors should last the length of the One Lap.

Out of curiosity, how well does the CRX put down power? My FWD experience is limited, but my 91 hp '85 CRX has a bit of trouble as does my classic Mini. They love to burn that inside front wheel. No LSD in either.

Tom Suddard
Tom Suddard Publisher
5/14/24 8:27 p.m.

For a 500-horsepower car, the CRX puts down power very well.

Sadly, though, it only has 300 horsepower. laugh It's not as bad as you'd think with the LSD, but there is a reason F1 cars are rear-wheel-drive.

Leaving corners requires patience, and launching requires starting in second gear and slipping the clutch for the first twenty feet or so.

Andy Hollis
Andy Hollis
5/14/24 8:44 p.m.
rdcyclist said:

Congrats on an Epic Showing amongst the Big Dogs of SSGT and then some. I have a coupla questions:

1. How did the 1L/CRX stay in Economy with the big ass engine swap along with big ass brakes and big ass wheels and tyres? Wouldn't that put it into some modified class? Did staying with a Honda engine keep it in class?

2. How did David manage to slay most of the Goliaths? I mean, E36 M3, you guys beat a ZL-1 Camaro being driven by a former PRO driver with a coupla rocks and a sling! That's berkeleyin' Amazing! And ended up about 28467 points ahead of second in class; apparently the rest of the Economy class brought a knife to the gunfight.

Besides all that, the transits were ... challenging. I think what Sam Smith wrote in his driving impression of the Shelby Daytona Coupe applies here: "If you sat down and designed a machine to make someone not want to do 180 mph in rainy race traffic at night, it would look an awful lot like this. Maybe more comfortable." The CRX was probably about like that...

Again, I stand in awe of your incredible performance.

1) OLOA rules don't care about mods.  It's all about what the car started life as.  In this case, the ultimate economy car.  Specifically, "cars under $25K" fit into economy.  But they also can't be "sports cars" cuz then they'd be in SGT1 or 2, big bore or small bore.  We also could have run Vintage, since we are easily under the 1991 born-on date.  We'd have won that, too.

2) Vintage woulda been more competitive, but not quite in line with GRM demographics, so we chose Economy.  That's also where we ran this car for four years some ten years ago.  Back then, it did not qualify for Vintage.

3) The CRX was cramped for me, but worse for Tom.  He has longer legs and the cage is built around me.  So the harness bar does not allow for sufficient space for his seat to allow full leg extension. 

Of course, halfway through the week Tom noticed that the harness bar bolts in.  So I coulda built one that allowed his seat to be further back.  Oh well...next time. Sorry, Tom.  smiley

 

RacingComputers
RacingComputers Reader
5/14/24 10:44 p.m.

Great POST MORTEM     Thanks

Andy Hollis
Andy Hollis
5/15/24 7:10 a.m.

Here's the classing rules I referenced earlier.  Note that paragraph at the end...it's the most important.

Due to entry count, the two Classic classes have typically run as one Vintage class lately.

1. Sports/GT cars over $50,000 - Engine displacement 3.5L and over
2. Sports/GT cars over $50,000 - Engine displacement under 3.5L
3. Sports/GT cars under $50,000 - Engine displacement 3.5L and over
4. Sports/GT cars under $50,000 - Engine displacement under 3.5L
5. Mid-priced sedans and wagons $20,000-$50,000
6. American Cruisers (American Sedans over 3.5 liters)
7. Economy cars under $25,000
8. Luxury sedans and wagons over $50,000
9. Sport Utility vehicles and pickups all price ranges
10. Classic American: All domestically produced vehicles built prior to 1991, including
street rods, specials, etc.
11. Classic Imported: All types built prior to 1991
12. Alternate Fuel class-including hybrids, electric, diesels, etc. (does NOT include E85
fueled vehicles)
13. Retro: Vehicles intended to reflect past trends or models, Minis, etc.


Note: Classification based on categories defined manufacturers' intent as determined by
the organizers. These dollar amounts are reflective of 2024 dollars and should be
adjusted for inflation for older vehicles, and used only as a guideline. Our main criteria is
manufacturer intent, not the actual dollar value, as to what segment of the market in
which the car designed to be sold.

Tom Suddard
Tom Suddard Publisher
5/15/24 8:02 a.m.

Note also that in One Lap Classing, trim doesn't matter. The base car MSRP is counted.

So a Hellcat and a base V6 Charger ring up as the same price. 

docwyte
docwyte UltimaDork
5/15/24 9:48 a.m.

I run caliper studs on my 911, even though I can remove the pads without removing the calipers.  The knuckles are aluminum and it's easy to damage the threads in them.  This way I just remove two nuts and pull the caliper off and don't worry about the knuckle.  If you swap to those larger Wilwood calipers, maybe you can run studs too...

Keith Tanner
Keith Tanner MegaDork
5/15/24 10:46 a.m.

In reply to docwyte :

Ooo, interesting idea.

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