The Autocross thread. Got questions? Get them answered here!

[Twinz]

I just try to make a quick, smooth transition from wheel spin to hook-up without letting the revs drop too low. Just glanced back at my last event's data and my best launch kept the RPM's above 4600. I don't side-step the clutch, but there's not much clutch slippage either.

[ame="https://www.youtube.com/watch?v=O6anJlxY3lQ"]GCAC autocross Fort Myers 2-5-17, best run 63.295 - YouTube[/ame]

The turn kept the wheel spin going a little longer than normal, but this is otherwise a typical launch for me.

[dutchman1]

Thanks for the responses, I'll work on it! Allowing a tiny bit of clutch slip at a higher rpm makes sense, I'll give it a shot.

[renfield90]

Originally Posted by dutchman1

Thanks for the responses, I'll work on it! Allowing a tiny bit of clutch slip at a higher rpm makes sense, I'll give it a shot.

I've tried a number of different methods: clutch dump with bog, clutch dump with (managed) wheelspin, little bit of clutch slip, lotsa clutch slip (but not so much I could smell anything). I also did all these variations either at a ProSolo or a drag strip, so there was actual timing equipment available to judge my 60' times.

For me, lots of clutch slip and no tire spin was always the best method. Especially on street tires, once they spin in earnest you're going nowhere fast - you're either going to bog trying to bring the spin under control or you'll wait too long for the car to speed up to a range where the tires can hook up and keep you in your power band. In CS trim on Lincoln concrete I could consistently cut 2.1-2.2 60' times all day.

I generally don't bother with that at regular autocrosses unless there is a legit drag race start. I'll typically go with a somewhat aggressive dump, spin the tires a bit (because it's fun, it puts on a show, and it puts some rubber down for my next launch) and go. If there isn't a drag start you are better off focusing on executing the course than worrying about the launch, just my 2 cents.

[trippinbillies40]

Interesting. Dave Marcus was killing me on 60' times at the Wilmington Pro in '15. He said higher revs for the launch. It dropped almost two tenths off my 60' by clutch dump from 5k and managing the spin after that.

[renfield90]

Originally Posted by trippinbillies40

Interesting. Dave Marcus was killing me on 60' times at the Wilmington Pro in '15. He said higher revs for the launch. It dropped almost two tenths off my 60' by clutch dump from 5k and managing the spin after that.

Yeah, at Lincoln or other concrete sites I do 5k and slip. Asphalt sites I do 4k and slip. I find it really hard to manage the wheelspin at 5k on asphalt and every time I spin the wheels I get a slow 60'.

It's possible I just have no chill when it comes to spinning wheels and can't manage it like some can.

[M0nk3y]

Originally Posted by trippinbillies40

Interesting. Dave Marcus was killing me on 60' times at the Wilmington Pro in '15. He said higher revs for the launch. It dropped almost two tenths off my 60' by clutch dump from 5k and managing the spin after that.

Well, looks like I need some adjustments...

I'm use to clutch dropping at 2300 RPM

[M0nk3y]

Originally Posted by renfield90

I've tried a number of different methods: clutch dump with bog, clutch dump with (managed) wheelspin, little bit of clutch slip, lotsa clutch slip (but not so much I could smell anything). I also did all these variations either at a ProSolo or a drag strip, so there was actual timing equipment available to judge my 60' times.

For me, lots of clutch slip and no tire spin was always the best method. Especially on street tires, once they spin in earnest you're going nowhere fast - you're either going to bog trying to bring the spin under control or you'll wait too long for the car to speed up to a range where the tires can hook up and keep you in your power band. In CS trim on Lincoln concrete I could consistently cut 2.1-2.2 60' times all day.

I generally don't bother with that at regular autocrosses unless there is a legit drag race start. I'll typically go with a somewhat aggressive dump, spin the tires a bit (because it's fun, it puts on a show, and it puts some rubber down for my next launch) and go. If there isn't a drag start you are better off focusing on executing the course than worrying about the launch, just my 2 cents.

No offense, but I'm going to call BS on 2.1 and 2.2 at Lincoln.

Considering 2 FRSs at the Finale in CS...they were both mid to high 2.3s

STX no better

[trippinbillies40]

Originally Posted by M0nk3y

Well, looks like I need some adjustments...

I'm use to clutch dropping at 2300 RPM

You're used to torque

[renfield90]

Originally Posted by M0nk3y

No offense, but I'm going to call BS on 2.1 and 2.2 at Lincoln.

Considering 2 FRSs at the Finale in CS...they were both mid to high 2.3s

STX no better

See Spring Nats Pro and Finale 2015.

[renfield90]

Keep in mind, your 60' is ALL about the launch. Horsepower matters little especially on street tires. The 350Z, E36 M3, etc. would walk me all the way to the first actual cone on course but according to the timesheets I was always faster than them to 60'.

Same goes at the strip. I beat a lot of 5.0s to 60' (one Shelby I even beat to 1/8 mile, lol) because they couldn't meter the power enough to hook up and scoot forward. The seasoned guys on drag radials or slicks though, I didn't have a chance.

[Briankbot]

Originally Posted by M0nk3y

No offense, but I'm going to call BS on 2.1 and 2.2 at Lincoln.

Considering 2 FRSs at the Finale in CS...they were both mid to high 2.3s

STX no better

I'll back up Manfred on this a bit. My technique is similar to what he described. While I was consistently hitting 2.3s at 2016 Spring Nats I did manage 2.2 in CS trim. That was only my second Pro ever and I'm sure with some practice and setup tweaks 2.1s could be possible.

Manfred, I'm curious were you on BFGs or B-Stones?

[renfield90]

Originally Posted by Briankbot

Manfred, I'm curious were you on BFGs or B-Stones?

I was on 245 BFGs. The tire feels kinda sloppy and numb being pinched on a 7" wheel but I felt it was worth the trade off, especially at pros.

[nastynate88]

Hey CSG Mike,

I've been doing some research on reliability of the 86's for tracking and autocross (arguably what the car is designed for), and I came across a reddit thread from a few years ago where you mentioned the motor will get tired after a while and will need a rebuild after 20 or so weekends. I'm pretty sure this was more in regards to tracking rather than auto-x, but could you elaborate on what you meany by all of that?

I'd ideally love to keep this car forever, but is a full engine rebuild something I'll need to consider sometime down the road if I choose to track car regularly/competitively (2014 model)?

Also, thanks for being so active in the community.

[sniffpetrol]

Do you guys run your autox tires on the street? In the past I've had r-comps for my old Miata which I changed out just for autox, but with a tire like the RE71R I am wondering whether I should do the same thing or just run them in the summer on the street also. I'm mostly wondering because I go on the occasional road trip and it seems like a waste to be using sticky tires for so long on the highway. Thanks.