Interested in auto crossing - classing question

[TonyG]

Hey guys,

Always love road racing, looking get started with it through auto crossing.

Car is a 1992 5.0 Mustang. Modifications:
Coil over front suspension
Adjustable rear control arms (jack screw)
Panhard bar
Adjustable shocks at all four corners.
Caster/camber plates
4 wheel discs, larger front discs
306ci heads, cam, intake.
Stock 5 speed transmission

Driver, 39 yrs old, kid at heart, loves going fast, but loves being safe and going home to my kids every night!

[RichardBasford]

Re: Interested in auto crossing - classing question

Hey Tony,

I can't help much on the classing, just wanted to say welcome to the club! Sounds like a super cool car!!

Rich

[traum]

Re: Interested in auto crossing - classing question

Hello Tony! And welcome to VCMC and autox!

With the head and cam mods, I think your Mustang will go into the Street Modified (SM) class.

One issue I'd like to bring up is, a lot of the American V8 cars have a tendency to blow our sound limit at the Pitt Meadows venue. This is especially common when it comes to modified muscle cars. FYI, the noise limit is 92 dB measured from 50 feet away, perpendicular to the direction of travel. So please keep that in mind.

Hope to see you on the pad when our 2016 season begins!

[TonyG]

Re: Interested in auto crossing - classing question

Thanks for the comments guy!

With regards to the db restriction, I would assume that's not at idle ? Do you guys test for that, or could you suggest where I might be able to get that tested?

Edit - i see Mission Raceway has a limit of 90db for the Friday night street legals, and there are a lot of Mustangs that run there.

[traum]

Re: Interested in auto crossing - classing question

Hey Tony,

The sound limit is measured at whatever point on the course that we deem would produce the loudest tire and/or exhaust noise. Typically, we either pick an aggressive acceleration point where we expect the engine to be in the higher rpms , or a place where drivers would just be coming off the gas, and we try to catch any resonance from the resulting change. As was mentioned in my previous post, the measuring methodology is using a sound meter at 50 feet away and perpendicular to the direction of travel.

In general, we have a rough idea of what kind of engine / exhaust noise would likely get close to or break the sound limit. So if you bring your vehicle to one of our events (as a participant), we can often tell if the car will likely exceed the limit. But to be certain, you'd have to sign up for an event, and run the car on course for us to measure.

I would also like to add that while the Mission Raceway maintains a 90 dB sound limit, the method of measurement is likely a little different, and what might pass at Mission Raceway with the seemingly lower dB limit may or may not our 92 dB limit at the autox pad. But if you are interested, the club typically host a number of track days at the Mission Raceway as well. So please stay tuned for that if HPDE / lapping is your thing.

[motoring]

Re: Interested in auto crossing - classing question

The other classing option (if you are offering it) is CAM; as long as the mustang still has the interior, and runs on 200tw tires.

[traum]

Re: Interested in auto crossing - classing question

The other classing option (if you are offering it) is CAM; as long as the mustang still has the interior, and runs on 200tw tires.

Yes, the CAM-C class (classic american muscle -- contemporary) would be the class to use if your Mustang still has a full interior and runs on 200TW (or higher) tires. CAM-C has a much better PAX than SM (0.839 vs 0.87), so that's where you want to play.

[TonyG]

Re: Interested in auto crossing - classing question

Yes, full interior. Power windows and door locks, and a great stereo!

Tread wear 200, what does that limit me to? Most street tires?

[traum]

Re: Interested in auto crossing - classing question

Yes, 200TW would be the minimum wear rating for most street tires. But there are some very good ones around, and unless you prefer trailering your car between events, you'd probably be driving on street tires anyway.

[TonyG]

Re: Interested in auto crossing - classing question

Something like this? Clearly wouldn't do me any good if it were damp out, but for dry conditions?

http://m.tirerack.com/tires/TireDeta...del=ADVAN+A048

[motoring]

Re: Interested in auto crossing - classing question

no... those are 60 tread wear. look for the UTQG listing in the tire description.

The two hot tires are the Bridgestone RE71R and the BFGoodrich Rival S,

[traum]

Re: Interested in auto crossing - classing question

That A048 is actually a 60TW tire. You can certainly use it, but it would send you to SM class instead of the CAM-C class with the more favourable PAX index.

In case you are not familiar with the autox PAX system, it is a lap time multiplier / modifier that is used to calculate a PAX score. The PAX score is then used to determine the seasonal competition ranking. Even if they are not competing for the whole season, most drivers use that PAX score as a gauge to see how their driving compares to other drivers in the club. But at the end of the day, it depends on whether you are more interested in the competition aspect of autox, or whether you are more interested in finding yourself the most grippy tires you can get your hands on to have the largest dose of fun.

If you care to tell us what tire size your Mustang uses, we could probably suggest a few 200TW tires that would work reasonably well.

[TonyG]

Re: Interested in auto crossing - classing question

Wound up going with Michelin Super Sports 255/35-18 and 285/35-18. TW300. Hopefully a good balance of street tire and something that will be sticky enough to have some fun with.

[traum]

Re: Interested in auto crossing - classing question

Ha! I hope you'll like them! When you're out autox-ing with them, you might even find yourself wishing that there is some light rain!

[TonyG]

Re: Interested in auto crossing - classing question

Well I'm picking it from the shop that did the brake work for me on Thursdays, which means I'm going to be driving it home in a monsoon......should be interesting. Light rain would be fun for xcrossing, standing puddles not so much.