Got a track related question? I'll try to answer.

[strat61caster]

Originally Posted by 86Craze

What tires to run in SM class? I am currently on RE71s, should I stick with it ?

How competitive do you want to be?

http://www.ft86club.com/forums/showthread.php?t=85774
If you want to build a competitive SM car, Hoosier A7's, as big as your wheels and fenders will allow, the class is indexed around cars that have 295-315 sized slicks and >400hp.
Let's put it this way, a Nissan GT-R showed up at Nationals and placed 8th in SM behind built 240sx's, Evo's, and WRX's.

But, if you're just out to have fun the RE71R's or BFG Rival S 1.5 mean you can drive to the event on the tires and drive home with little worry and still be on quick rubber. Switching to Hoosiers and stiffening the suspension to get the most out of them may make the car miserable on the street, towing a tire trailer and swapping at events is a burden imho. Some clubs have special indexed classes where you can run street tires against other people that have a car not eligible for Street or Street Touring but don't want to use slicks.

reminder for all that there is a dedicated autox question thread:
http://www.ft86club.com/forums/showthread.php?t=114202

[finch1750]

Originally Posted by jjaisli

I did a few years ago with an iPhone 6. Surprisingly the times were within about .2 of a lap or less over 3 laps vs an AIM Solo in the car.

IMO, for out right timing, Harry's and a modern smart phone do a surprisingly good job. Where it falls short, is when you export the data and try and work with it. The data overlay is improved if you use an OBDII dongle, but when you're dealing in 0.1, between on/off throttle, the amount and frequency of data points being collect by Harry's falls short. I remember looking at data collected at the bus stop at WGI 2 years ago, trying to compare a brake trace [Edit: between multiple laps] (Harry's doesn't, at least not on a twin) and looking at throttle tip in, there just wasn't enough data points to really do a proper comparison.

EDIT: My ultimate conclusion is this: Harry's Lap Timer does a good job if you want to time yourself. And it will give you relatively accurate lateral g loading. You can look at your laps and see where you can maybe push a bit harder here or there. Where it falls short is if you want to actually work with that data and compare multiple laps and really see where you're gaining or losing time.

That's kinda what I figured. I'm so new to tracking I figure it was good enough to give me an idea on improvements and consistency by itself.


From what I've read with the external it does a decent job for data acquisition. I don't think I'm ready to drop $600 on an Aim at the moment.

[jjaisli]

Originally Posted by finch1750

That's kinda what I figured. I'm so new to tracking I figure it was good enough to give me an idea on improvements and consistency by itself.


From what I've read with the external it does a decent job for data acquisition. I don't think I'm ready to drop $600 on an Aim at the moment.

I agree. The app is cheap. And it's good for what it is.

[CSG Mike]

Originally Posted by finch1750

Has anyone done a comparison of Harry's Lap Timer with phone GPS compared to an external or AiM? I will be buying Qstarz before my next track day but am curious/trying to settle an argument lol

1hz vs 10hz. +-1s vs +- 0.1s.

HLT is good for a relative lap time but useless if you want to see speeds or get an accurate lap time.

If you're using a phone mount that will vibrate, then the data will also be contaminated.

[cjd]

Originally Posted by finch1750

Has anyone done a comparison of Harry's Lap Timer with phone GPS compared to an external or AiM? I will be buying Qstarz before my next track day but am curious/trying to settle an argument lol

For AutoX it's far short of useful.

If you're collecting high level data about lines on a track, it may be good enough for a bit. It won't help you if you need to adjust a braking point, where the range of adjustment may be shorter than a 1Hz window lets you observe properly.

Even with a 10Hz option I found a surprising amount of inconsistency in where it put my car at any given time. Not sure if that's Harry's at fault or not though. I wish it would make use of the g-sensor in the car rather than the phone... though I don't know if it even uses that for placement.

C

[CSG Mike]

Originally Posted by cjd

For AutoX it's far short of useful.

If you're collecting high level data about lines on a track, it may be good enough for a bit. It won't help you if you need to adjust a braking point, where the range of adjustment may be shorter than a 1Hz window lets you observe properly.

Even with a 10Hz option I found a surprising amount of inconsistency in where it put my car at any given time. Not sure if that's Harry's at fault or not though. I wish it would make use of the g-sensor in the car rather than the phone... though I don't know if it even uses that for placement.

C

You may like the AIM Solo 2 DL.

[cjd]

Originally Posted by CSG Mike

You may like the AIM Solo 2 DL.

First I have to finish getting the new car put together... It was previously in the budget for this year. wish I'd had it when my old car was crashed to see just where and how corrective action was taken... Or not taken. That would have been for curiosity though, as the driver's story lines up with the video and my experience of things.

Harry's was good for figuring out what data could do/where it is useful if it were clean enough. Connecting the intellectual understanding with the experience.

C

[finch1750]

Originally Posted by cjd

For AutoX it's far short of useful.

If you're collecting high level data about lines on a track, it may be good enough for a bit. It won't help you if you need to adjust a braking point, where the range of adjustment may be shorter than a 1Hz window lets you observe properly.

Even with a 10Hz option I found a surprising amount of inconsistency in where it put my car at any given time. Not sure if that's Harry's at fault or not though. I wish it would make use of the g-sensor in the car rather than the phone... though I don't know if it even uses that for placement.

C

So far I've just been using it to track relative lap times for an idea of where I'm at and improvement. Just did my 3rd event so my times are cut in big chunks so +/-1sec has been OK. Definitely want the 10hz to start looking a little more into things

What external where you using? I read somewhere the Qstarz only works at 5hz instead of 10hz with Harrys (effectively at least)

[cjd]

Originally Posted by finch1750

So far I've just been using it to track relative lap times for an idea of where I'm at and improvement. Just did my 3rd event so my times are cut in big chunks so +/-1sec has been OK. Definitely want the 10hz to start looking a little more into things

What external where you using? I read somewhere the Qstarz only works at 5hz instead of 10hz with Harrys (effectively at least)

Dual XGPS160

[finch1750]

Originally Posted by NoHaveMSG

Is there a specific reason why? I have seen plenty of threads on these pads that you have commented on and not mentioned this before.

FWIW I love these for street/canyon/autox, but quickly outgrew them on track. My current set the fronts are toast after 2 track days and about 5k street miles. And that is with a respectable time given my experience (only 3 track days) but I am still 5-10 seconds off 86cup times in the same class depending on the track. So it doesn't take much to outgrow them.


I'm jumping to Winmax W5 and separate rotors for track going forward and then swapping to stoptechs for daily use

[NoHaveMSG]

Originally Posted by finch1750

FWIW I love these for street/canyon/autox, but quickly outgrew them on track. My current set the fronts are toast after 2 track days and about 5k street miles. And that is with a respectable time given my experience (only 3 track days) but I am still 5-10 seconds off 86cup times in the same class depending on the track. So it doesn't take much to outgrow them.

I toasted mine too in about 3 track days and as many miles. I just saw them brought up so much it made me wonder.

[CSG Mike]

Originally Posted by NoHaveMSG

I toasted mine too in about 3 track days and as many miles. I just saw them brought up so much it made me wonder.

Sounds like it's time for you to step up to a Sprint type pad!

PM me to order.

[finch1750]

Planning to get my headers coated this summer. Is it worth it to get the overpipe coated while I'm at it? Or is it far enough back that it doesn't really mater?

[cjd]

Originally Posted by finch1750

Planning to get my headers coated this summer. Is it worth it to get the overpipe coated while I'm at it? Or is it far enough back that it doesn't really mater?

If you're running a cat, keeping as much heat in the system as you can helps... I think. At least, getting it up to operating temp faster. Curious if there are more informed answers on this.