82 replies to this topic

[Alberto]

Thanks to all for their input. All the comments are helpful.
Alberto, up until that spin, I had always used heel-toe from 4th down to 3rd for Rd Atl T6. The video is the only time i thought i'd try leave it in fourth and just go faster around the corner. Since my first attempt at staying in 4th resulted in a spin, it was my only attempt. For all future laps, i went back to downshifting to 3rd.

I definately need more skidpad practice to get faster hands. And the car may be too loose.

Brendan

Incident #1 you downshifted to 3rd and that looked clean but then right away you started your turn-in and weren't applying throttle according to the RPM at the top of the vid. Seems like the rear end got light as you were cresting the hill and starting your turn-in. Some light throttle may have transferred weight to the rear to keep it planted. Street suspension and tires don't help.

Incident #3 makes it seem like the car is setup a little loose. Maybe it has some toe out on the rear tires or not enough camber. The incident also happened when you were off throttle and turning in. Seems like you started giving it throttle for a split second and then the rear got away from you.

Incident #4 Seems like you got the entry wrong the corner before it and wound up messing up the turn and going wide. Then it looks like you just gave up on it.

Incident #5 makes it seem like the car is setup loose and also, since you weren't on the gas pedal, the rear end didn't have any weight on it to keep it planted and it came around.

My .02 cents. I could be wrong. Check your sway bar settings and double check that you installed the correct springs on each corner and get a pro to align and corner balance the car.

[D Tesch]

Incident #1 you downshifted to 3rd and that looked clean but then right away you started your turn-in and weren't applying throttle according to the RPM at the top of the vid. Seems like the rear end got light as you were cresting the hill and starting your turn-in. Some light throttle may have transferred weight to the rear to keep it planted. Street suspension and tires don't help.

Incident #3 makes it seem like the car is setup a little loose. Maybe it has some toe out on the rear tires or not enough camber. The incident also happened when you were off throttle and turning in. Seems like you started giving it throttle for a split second and then the rear got away from you.

Incident #4 Seems like you got the entry wrong the corner before it and wound up messing up the turn and going wide. Then it looks like you just gave up on it.

Incident #5 makes it seem like the car is setup loose and also, since you weren't on the gas pedal, the rear end didn't have any weight on it to keep it planted and it came around.

My .02 cents. I could be wrong. Check your sway bar settings and double check that you installed the correct springs on each corner and get a pro to align and corner balance the car.

[Brendan O]

Incident #1 you downshifted to 3rd and that looked clean but then right away you started your turn-in and weren't applying throttle according to the RPM at the top of the vid. Seems like the rear end got light as you were cresting the hill and starting your turn-in. Some light throttle may have transferred weight to the rear to keep it planted. Street suspension and tires don't help.

Incident #3 makes it seem like the car is setup a little loose. Maybe it has some toe out on the rear tires or not enough camber. The incident also happened when you were off throttle and turning in. Seems like you started giving it throttle for a split second and then the rear got away from you.

Incident #4 Seems like you got the entry wrong the corner before it and wound up messing up the turn and going wide. Then it looks like you just gave up on it.

Incident #5 makes it seem like the car is setup loose and also, since you weren't on the gas pedal, the rear end didn't have any weight on it to keep it planted and it came around.

My .02 cents. I could be wrong. Check your sway bar settings and double check that you installed the correct springs on each corner and get a pro to align and corner balance the car.

Thanks Alberto!! I will definatley get a good shop to do alignment and corner weights. You are most likely correct that the car is not setup correctly.

So for incident 5 (Rd Atl T6), I just want to make sure i understand. Let's say I am trail braking. I have turned in and am heading towards apex with brake pressure. Let's assume the rear starts to step out due to too much brake pressure for the given lateral Gs. I think you are saying the best plan of action is to quickly move from brake to throttle and give "some" throttle to plant the rear and stop the rotation (in addition to quick hands). Do I have this right? I'll admit that I sometimes get confused when reading books on racing. For example, i initally thought that going to throttle after the rear steps out during trail braking would make things worse but what you said about using throttle to plant the rear (i.e. transfer more weight to rear axle) makes more sense.

thanks again
Brendan

[Alberto]

Thanks Alberto!! I will definatley get a good shop to do alignment and corner weights. You are most likely correct that the car is not setup correctly.

So for incident 5 (Rd Atl T6), I just want to make sure i understand. Let's say I am trail braking. I have turned in and am heading towards apex with brake pressure. Let's assume the rear starts to step out due to too much brake pressure for the given lateral Gs. I think you are saying the best plan of action is to quickly move from brake to throttle and give "some" throttle to plant the rear and stop the rotation (in addition to quick hands). Do I have this right? I'll admit that I sometimes get confused when reading books on racing. For example, i initally thought that going to throttle after the rear steps out during trail braking would make things worse but what you said about using throttle to plant the rear (i.e. transfer more weight to rear axle) makes more sense.

thanks again
Brendan

Keep in mind that I'm not an expert. Just giving my input, which I hope is helpful and accurate, since others haven't chimed in with opinions. I only have one rookie season under my belt in SM but have been doing track days in other cars for ages. What happens with Throttle application can vary depending on the car and the specifics of the corner. Now that the disclaimer is out of the way...

So for incident 5 (Rd Atl T6), I just want to make sure i understand. Let's say I am trail braking. I have turned in and am heading towards apex with brake pressure. Let's assume the rear starts to step out due to too much brake pressure for the given lateral Gs. I think you are saying the best plan of action is to quickly move from brake to throttle and give "some" throttle to plant the rear and stop the rotation (in addition to quick hands). Do I have this right?

Yes, you interpreted my statement correctly. Trail braking can be a challenge on some corners since it will make the rear end light. It just doesn't work in some corners. From what I can tell of that corner, I don't think you want trail brake. I think you want to brake to slow the car and then turn-in and start applying throttle.

Check this guy's vid paying attention to his lines and listening for throttle application for Incidents #4 and #5
http://www.youtube.com/watch?v=ww8NiKUtBYI

Hope that helps.



Bringing this back on topic of using data to analyze lap times, if you had a brake pressure switch, you/we would be able to see that you were going into T6 with trail brake. GPS would just tell you that you were slowing down but not what controls you were using to do so. In the absence of a brake pressure switch, you can probably hook up an idiot light on the dash that illuminates when you are on the brake. This way people can see it on video and understand what controls you were using.

[Chris Adams]

Disclaimer: I am still learning as well, as we all are, but this is how I manage trail-braking and it works for me.

As you're release the brakes more and more you are trasferring that weight back to equilibrium. You never want to pounce on the gas or it will upset the transferr too quickly and cause more oversteer, always transition smoothly back onto the gas and sqeuuze the throttle. As the rear end sits youll be able to judge with confidence the amount of throttle you can apply.

If you find that you trailed too late into the corner the best thing to do is to slowly let off the brakes, steer into the slide and wait for it to grip. Then you can maneuver into the gas. As you get more confertable/familier with the trail brake then you can feel when to begin training off the brakes and squeeze into the throttle. When your transition is smooth you will feel the rear end gaining grip and you ease into the throttle and before you know it youll be at full throttle exiting the corner at maximum speed.

Remember, exit speed is always more beneficial than entry speed... so in my opinion trail braking is used sparingly...I am also not a pro racer so waht do I know :|

Edit: After reading the post above, I realized this is off topic, sorry!

[Brendan O]

From what I can tell of that corner, I don't think you want trail brake. I think you want to brake to slow the car and then turn-in and start applying throttle.
Check this guy's vid paying attention to his lines and listening for throttle application for Incidents #4 and #5

I have actually watched this video several times and it is helpful.

And you are probably right. I don't need to trail brake just yet. Since my best lap (1:50) is 5 or more seconds off what would be considered "pretty good" (1:45), I think i have bigger fish to fry than trail braking. I should probably just concentrate on a smooth, consistent line, hit all my marks, and make sure my speed is correct for turn in. I will probably finish most of my braking before turn in. The goal for my next weekend in early March (NASA SE HPDE event) is to try bring each corner close to max lateral G. If I am not WOT, then I better be close to max lateral G or braking hard getting ready for turn in at correct speed. That’s the plan anyway.

Bringing this back on topic of using data to analyze lap times, if you had a brake pressure switch, you/we would be able to see that you were going into T6 with trail brake. GPS would just tell you that you were slowing down but not what controls you were using to do so. In the absence of a brake pressure switch, you can probably hook up an idiot light on the dash that illuminates when you are on the brake. This way people can see it on video and understand what controls you were using.

I have an AIM EVO4 logger. Roger Caddell (a very helpful AIM/data analysis guy – see his posts in this thread) and I decided on a good quality ($250) string pot for throttle position and a good pressure sensor for brake pressure. The brake pressure sensor will give actual pressure (PSI or %) instead of just on/off. They are being installed as we speak. I use Dashware software with my Chasecam video so I can easily add a brake pressure gauge overlay to the video so people will see exactly how hard I am pressing the pedal.

Thanks again
Brendan

[Brendan O]

Remember, exit speed is always more beneficial than entry speed... so in my opinion trail braking is used sparingly...I am also not a pro racer so waht do I know :|

Edit: After reading the post above, I realized this is off topic, sorry!

It is not off topic at all – it is right on target. I started thread asking how a beginner should use data to reduce lap times and that led to a discussion of some data I had that showed where some trail braking led to a spin. So your comments are on point.

I agree that trail braking may not be the best thing for me to focus on now. Instead I will focus on braking “mostly” in a straight line but making sure I always turn in at correct speed instead of too slow which is what my data showed me. Some corners would have max lateral G of only 1.1 give or take when I know car and Hoosiers can go up to 1.4. So I was WAY too slow in some of the corners.

Thanks
Brendan

[D Tesch]

You can analyze data till you are blue in the face. Remember you are racing a miata not F1. Find someone who can put a good base setup on your car. Take it to open track days or pre race test days and get as much track time as possible and learn to feel the car.All the data in the world does not make a good driver. Boris Said has a favorite phrase, DRIVE THE CAR! Everylap is a learning experience!

[Bruce Wilson]

Reading through the last couple posts, I'm reminided of the saying, Practice Doesn't Make Perfect, Perfect Practice Makes Perfect. You should do anything and everything to find out where on the track you are slower than others and why, and you should trail brake at least a little until you start to master the technique,but remember that trailbraking is not appropriate for every corner.

-bw

[Tom Hampton]

Reading through the last couple posts, I'm reminided of the saying, Practice Doesn't Make Perfect, Perfect Practice Makes Perfect. You should do anything and everything to find out where on the track you are slower than others and why, and you should trail brake at least a little until you start to master the technique,but remember that trailbraking is not appropriate for every corner.

-bw

+1

You can't learn what you do not practice.

[Brendan O]

ok then. What type of corners are good candidates for trail braking in an SM?
thanks

[Bruce Wilson]

Depends on the corner -- At PIR we have two coners 6 and 7 that are very different. Looking at the data we see slight or no trailbrakking in T6 and lots of trailbraking in T7. T6 is a faster corner with a bit of off camber and T7 is a tighter corner with banking that you you can pretty much choose between 2nd gear or 3rd gear depending on the situation. In T6 the car usually points well (front end works without needing to have more weight on front wheels) and when you trailbrake deep into the corner it pretty much always upsets the car, so we brake in a straight line and get back on the gas as soon as the car takes a set. T7 is almost the opposite, especially if you are using 3rd gear. In this corner you want the car to turn in and rotate, so you want to trailbrake deep (patience is key here), which provides more front end grip and loosens the car for more of a controlled drift providing good rotation. Since T6 sets you up for T7 and T7 leads to a long straight, getting it right is a big factor for fast laptimes at PIR.

Bottom line is you just need to get a feel for what is happening with the car in each corner and adjust as necessary.

[Brendan O]

ok - thanks

[granracing]

Driver coach now or later? This really depends on who you can find to help you while at DE events. Keep in mind that a fast driver does not necessarily mean a great coach (or even vice versa). Get as much coaching now and throughout your racing career. I find it somewhat funny how many racers after winning some events and setting some track records start to think they're above coaching.

Another recommendation IMO is to stop worrying so much about lap times. Focus as much as you can on becoming a better driver, and learn race craft. Just because a person can do quick laps during a HPDE doesn't mean they'll be a good racer. Learn to become very smooth with all inputs, be fast off line, and constantly look for ways to improve.

You'll also find that lap times will usually drop quickly as you move from HPDE to a race. Don't put too much pressure on yoursel by comparing it to what SM times are.

One other key element that I often need to remind myself is to have fun with all of this along the way.

[plane]

Since this is the best data thread, I would like to go slightly off topic.... In using/sharing data, goes anyone have good AIM track maps with turns?

[Brendan O]

Granracing - i will get a coach for some sessions this year. I think it will help. As far as not paying too much attention to my lap times, i'm going to have a hard time with that one. Unfortunately, i've become addicted to checking my times and seeing if i'm getting faster, which corners are good, which need improvement etc etc. I spend WAY too much time looking at data - i guess i have a problem

[Brendan O]

Since this is the best data thread, I would like to go slightly off topic.... In using/sharing data, goes anyone have good AIM track maps with turns?

I would love to get the same thing. I wish I could overlay my GPS laps onto an exact map of the track with all the curbing shown. That would be awesome. You'd think someone could just walk around the inside of the track and then the outside of track with a GPS and then create a map file. I bet AIM provides a way to do this using Google Maps or Google Earth but I haven't figured it out yet. When looking at the GPS laps, i have no idea if i'm 1 ft away from apex or 5 ft away. I know GPS is not that accurate but AIM EVO provides a cool feature where it logs the position error at 10 or 20Hz and IIRC it is usually less than 5 ft. At least I can overlay my data into my video but an exact track map inside Race Studio would be cool (Roger, if you're reading, please advise).

[Roger Caddell]

Yes, AiM Race Studio 2 will create a .kml file under the "File=>Export KML file for Google Earth" menu structure. Make sure you have Google Earth installed (free web download) and just save the .kml file and click on it and Google Earth will open and zoom into the track and show where you drove,

Be aware that yes there is some inaccuracy in all GPS data but I have found inaccuracy in the imagery in Google Earth... really depends on the track. Some are great and others are not.

[Roger Caddell]

BTW, I will be presenting data seminars pretty much every weekend somewhere in the country starting next weekend in Philadelphia, PA. Typically they are from 9am to 4pm and are little or no cost to the attendee. If you were a part of the brief data webinar we held for the MazdaRacers.com group or have watched the replay, these will be the long version of that with lots of in depth discussion and hands on experience.

Take a look at the upcoming seminars and if you want any more information on how to register, contact me and I will get you pointed the right direction:

• 2/4/12 - VAC Motorsports, Philadelphia, PA
• 2/11/12 - Capaldi Racing, Chesterfield, MI
• 2/19/12 - Empire Karts, Redlands, CA (karting specific)
• 3/4/12 - Currie Enterprises, Anaheim, CA (off road specific)
• 3/10/12 - Porsche Club, Stratham, NH
• 3/11/12 - Porsche Club, Stratham, NH (advanced)
• 3/17/12 - Body Motion Porsche, Ocean, NJ
• 3/24/12 - Pegasus Racing, New Berlin, WI
• 3/31/12 - Virginia International Raceway, Alton, VA
• 4/14/12 - Franklin Motorsports, New Berlin, WI (karting specific)

If you have an interest in hosting a seminar in your area, drop me a note and we will make it happen!

[Brendan O]

Roger, Thanks for tip on Google Earth maps. I'll try it.

Also, do you have SE dates yet? Atlanta, Birmingham ...