Sunday, November 24, 2013

Charlotte Chump Race - Take 2

As some of you may have known, ChumpCar was nice enough to rebook us for another race at Charlotte Motor Speedway since the previous one ran less than smoothly.

Zip6Racing had a good bit of work to do in preparation for the event, but it was an order of magnitude less than for the previous event.  The car had a few issues at the last race, and we wanted to fix those as well as make a few improvements.  A portion of the list:

Flush engine/radiator
Diagnose charging system
Trace MAF issue
Remount bumper
Plug header hole
Fix melted wire loom
Put pins in window net bar
Fix hole/replace tire
Check front brakes
Check rear brakes
investigate low oil pressure
fix camera system
fabricate headlight covers
better temp gauge
Head lights
Mount side windows
Replace rear window
Adjust pass. side windshield wiper
fix cylinder head temp sensor
check compression

The intermittent miss seemed to go away once we soldered in a new connector for the mass air flow sensor along with putting a jumper in the cylinder head temp sensor harness.  With the engine running better, that left us with 2 main things to worry over.

1) We had a tire that somehow suffered a puncture at the very end of the last race (possibly when loading it on the trailer).  We patched and plugged it, and it seemed to hold air.  We would have preferred to replace it, but every retailer seemed to have this tire in our size on backorder.  So we were crossing our fingers we wouldn't have an issue with the plugged tire.

2) Our venerable vg30 engine, as tough as it is, had been through a lot.  When we changed the oil, it looked ok, but we noticed it was smoking at good bit at idle.  A compression test confirmed our suspicions:
Compression test - not so good
Nissan's min for this engine is 128 psi.  We barely made that on the #3 cylinder.  Nissan also specs a max differential between cylinders of 14 psi.  We were nowhere close to meeting that.  From our inspection of the engine last year, we had
cyl #1 200psi
cyl #2 165psi
cyl #3 187psi
cyl #4 170psi
cyl #5 200psi
cyl #6 185psi
so even then we were flunking the max differential requirement.  And as you can see, the numbers had fallen dramatically after Race #1.  The engine was not healthy.  Our spare engine was in Columbia SC, and we really didn't want to go through the trouble of retrieving and installing it.  So... engine health was a worry.

We actually installed plexiglass in the rear hatch frame twice.  The first time, it looked cloudy, and it was removed only to discover an additional layer of peel-off film stuck to it.  Oops.  We really wanted to try and make the car more aerodynamic, as our top speed in the last CMS event wasn't competitive.  The combination of
- running without a hood
- no headlight covers
- no quarter panel windows
- no rear hatch
was in theory really killing our top end.

On Friday, the day when we needed to get the car through tech/safety inspection, we were a few minutes later than planned in getting the car on the trailer and getting our gear loaded, but it was nothing like the exhausting, nerve-wracking thrash before the last race.

We had a bit of a hiccup once we got to the track and realized the race car's brake lights weren't working.  We had packed several totes and boxes of parts into the car for transport to the track, and our assumption was a wiring harness was damaged by doing that.  Sure enough, one of the guys found a ground that had ripped out, and we quickly patched it up.  We had ordered a new CHTS plug, and it was scheduled to land at the local Nissan dealership at 11am.  While one of the guys went to pick it up, a few of us worked on spacing the new headlight covers upward to fit closer to flush with the hood.

The line for tech inspection was fairly short, but it still seemed to take awhile.  With no real surprises or disagreements, we made it through tech and spent a few minutes checking the fit of a spare tire and looking over the car one last time.  With little left that we could do, we all headed home to get some sleep for a 6:30am driver's meeting and a 7:00am race start time.

Ready to race and lookin' better than ever!
To be continued...

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