For those running SCCA Autocross... - Lateral-g Forums

Ben@SpeedTech · #1 03-16-2015, 01:12 PM

I've got 2 questions for the guys that run pro touring/ muscle cars in SCCA autocross events-

1.) I just attended an event with a region I haven't raced with before. They ranked all the cars fastest to slowest using a PAX time. What is a PAX time? I couldn't find a clear answer on the internet, just some dead links.

2.) My son and I are the only ones running CAM in the 2 closest SCCA regions. Mine is the faster car of the two and although it feels responsive and quick through the course, out of 40 cars at this last event I only beat 9 of them. Really the closest cars to compare to were some Corvettes and a couple new Mustangs. I was faster than one stock C5 corvette, but the 4 other Vettes that were modified beat me. The rest of the field that were faster were mostly all imports.

My car weighs about 3700 lbs with me, has about 325 hp at the flywheel, and runs on Nitto NT555 daily driver street tires. For comparison my best was a 69.7XX and the fastest car of the day (and always is the fastest) was a race prepped Lotus Elise on "DOT" slicks that ran a 56.XX. There was a 2015 Mustang Turbo that was 63.7XX in STU class but I didn't get to ask if it was modded at all or see what tires he had. A 2012 Boss 302 Mustang on "DOT" slicks ran 64.6. Only 4 cars broke into the 50s, the rest of the cars faster than me were in the 60s as well. The slowest of the day was my son at 76.XXX, also running a G body wagon with a fairly decent suspension but bone stock drivetrain. He drives fairly well, so I believe a big part of why he was slowest was because of lack of power more than anything.

My question is those of you that are running muscle cars at SCCA events, how do you compare? I've come to grips that I'll get my shorts handed to me by a lot of the cars, but what should I expect and be happy/ comfortable with as far as comparing to the new American and the little import cars?

SSLance · #2 03-16-2015, 02:10 PM

Are the result from your event listed online somewhere? If so share the link and I'll try to help decipher it for you.

PAX is like a handicap in golf, only it's based (loosely) on a car class, not the driver in the car. You should probably spend more time looking at the raw time results more than anything else until you get a feel for how things are going.

When you are looking at which cars finished where, pay less attention to the type of car and mods and more to the driver behind the wheel.

For an example, we typically have around 100 drivers at our SCCA events. When I first started, I usually finished around 70th in raw time. 3 years later, with a bunch of improvements to the car and the driver, I'm steadily in the 25-30th range out of 100 drivers and I regularly beat quite a few import cars with good drivers in them. The really good drivers in well prepped cars more built for this than my car still stomp me pretty good although I'm gaining on them every event.

SSLance · #3 03-16-2015, 02:13 PM

Oh yeah...tires...

R-Compound tires are generally worth 2-3 seconds over a 200 TW street tire on a typical 50 second course. You are running a 300 TW tire that will be even slower than the 200 TW tires.

Tires are HUGE in autocross...

MtotheIKEo · #4 03-16-2015, 02:28 PM

Like stated above, PAX is just a number to multiply your raw time by to compare the different classes. For example...
A Mod PAX = 1.000 (Should be the fastest time at the event)
SS (Stock Class) PAX = 0.843

So if the A Mod ran a 100 second lap, 1.000 X 100s = 100 seconds adjusted
If the SS car ran a 118.64 second lap, 0.843 X 118.64 = 100 seconds adjusted

It's just a way to compare times across classes.

As for your second point, horsepower is almost never the cause for a slow autocross time. Tires for me have always had the largest impact BY FAR. If you can come out of a turn and flat foot the throttle with no issues then maybe you need more power. If you are new to the game, then practice will be a huge contributor to improving times. Knowing how to line up multiple elements of the course, driving smoothly, etc... will all help.

Ben@SpeedTech · #5 03-16-2015, 02:44 PM

Lance-

I'll try to find out if they have the results online. My friend took a snap shot of their computer at the track and that's what I'm looking at.

It's that tire thing again, lol! I'm working on the new motor and the 9" rear so tires have to wait till after that.

Man, I wish we were closer, I'd love to compare my car to yours and since I'm fairly green to racing autocross, only 4 events under my belt now, would love some ride alongs and insight too.

Thanks for the explanation M.

My son can just about flatfoot it going into the corner, lol! His car is way underpowered, it runs high 17s at the drag strip. Not for long though, he's saving for a 5.3.

silver63c10 · #6 03-16-2015, 02:49 PM

Weight, tires, and driver are the biggest factors in autocross - horsepower can factor in on bigger courses, but it's still not a trump card even then.

The biggest thing starting out is getting seat time - both driving and riding. Find experienced guys, tell them you're just getting started, ask for a ride and get them to ride with you. Some clubs will do schools where an instructor will even take your car for a lap, which can be very eye-opening.

Point being, someone who's got experience instructing can tell you more after one or two runs than you'll learn in 5-10 events searching for time on your own.

Get video of your runs and watch them after the event is over, and find other people's videos. You can compare your lines, braking points, etc.

There's 100 other things, but that's what helped me out the most starting out. Most of all, make friends and have fun.

SSLance · #7 03-16-2015, 04:06 PM

Don't be afraid to let a veteran autocrosser drive your car on course as well and if you do, make sure to ride along with them.

Here are the raw time results from our last event last season.

http://www.kcrscca.org/results/solo/...vent13_raw.htm

I finished 42nd (49.692) out of 130 drivers. Fastest fender time was Mark Hill (46.088) in an Evo.

Look at Tyler's finish in 32nd (48.948), and his Dad Steve 66th (50.857) in the same "Scout". I've seen them finish right next to each other before at other events, that day just wasn't Steve's day apparently and Tyler was on it.

Here are the PAX results for the same day.

http://www.kcrscca.org/results/solo/...vent13_raw.htm

I finished 45th, Tyler finished 91st and Steve finished 112th.

Don't pay any attention to PAX right now, try to find the raw time results for the event. I'm sure they are posted up somewhere.

SSLance · #8 03-16-2015, 04:38 PM

I'll show just one more example here...to help you figure this out Ben.

Here are the raw time results from our second to last event last season. Not only was this was held at Heartland Park Topeka which let the course designers setup up a much more wide open nationals style course than we see at our regular site, but it was also pretty dern cold in the morning heats and warmed up considerably in the afternoon heats.

http://www.kcrscca.org/results/solo/...vent12_raw.htm

I finished 39th out of 91 drivers that day in raw time with a lot of the drivers I beat in the last event of the year finishing ahead of me in this event. Temps, which heat you ran in and type of course were majors factors in this. Cars and drivers were basically the same. I ran in heat 1 in the cold, whereas I normally run in heat 2 which would have been a tire grip advantage on that day. Same event, I PAX'd 46th out of 91 drivers.

http://www.kcrscca.org/results/solo/...vent12_pax.htm

I still beat a 2012 GS Corvette on Hoosier A6s by 6 tenths raw time that day. Chris beat me by almost 2 seconds at our last event of the year though which is a little bit more normal.

There is no rhyme or reason, show up run, do the best you can and try to get better for the next event. It'll start to click eventually and you'll notice it when you really start to pick up your times.

Ben@SpeedTech · #9 03-16-2015, 06:23 PM

Thanks Lance, I'll read over that later when I have a few minutes to soak it in.

So here's the big question- At all the SCCA events I've been to if you're not driving you're out on the course watching cones. If you are driving, it's go go go to get through the cars. Here they do 5 laps back to back, then watch cones, lunch, then 5 laps back to back and than watch cones.

I saw what seemed to be some good drivers while watching cones, but they have to watch cones when I drive and can't ride with me. When my gropup is driving I can't really see who are the better drivers, it's a pretty big course and I have to stay by my car so I don;t miss a turn.

Seems it would be hard to get someone more experienced to ride with you?

SSLance · #10 03-16-2015, 09:24 PM

What we do in a situation like that is make sure you run the same group as the other driver and just park about half way down the grid from them. That way they can run, get out and come straight to your car for your run...then have time to get back to his car for his run again.

We typically have 3 heats so that allow a heat off between work and run heats to help get things ready. We also only get one set of runs, usually 4 per heat.

So I show up at 7:30 am, usually work heat 0 at tech, have heat 1 off to get my car ready, warmed up, teched and in grid, run 4 runs in heat 2....then leave to go home about 2:30-3:00ish or so.

Fun huh...