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Racerflash
02-02-2013, 05:05 PM
4895 4896

My Solotime numbers came in today so she's ready to race! But, since I've never Autocrossed a FWD before, don't know if I'm ready???

trevc
02-02-2013, 05:21 PM
Have fun! I started autocrossing last year for the first time. The Abarth is a great car for this (even better with a few mods :eagerness:) I have done five so far and I am hooked!
Two weeks until my first 2013 race.

Racerflash
02-02-2013, 05:40 PM
Mine's in two weeks also. I've Autocrossed numerous times in RWD cars, but haven't run any events in almost 10 years. This is what I used to run, over 10 years younger and maybe 25 lbs lighter:

4897

shagghie
02-02-2013, 08:02 PM
Will be Solo'ing tomorrow in my Abarth as well... last time I auto-X was also 10+ years ago in a RWD 1973 FIAT 124 SC.
I've noticed that our Prima actually behaves better under hard breaking. The Abarth's rear is really squirrly by comparison.
I'm going to try 48PSI up front to help sort that out with firmer front suspension. Will push more, but this track is all about the breaks....

Saxonite
02-05-2013, 03:07 PM
I took mine out once last year for an event. Its a fun car to use. The biggest thing with FWD cars is to really make sure your slow in and fast out otherwise you'll spin the inside tire. I also left esc on my first run to warm up the brakes then turned everything fully off the rest of the time. This car reacts a lot better to progressive braking then just slamming on them like you can in some cars. This will let the suspension settle and keep the back end from stepping out. Overall its a fun car to drive. I think I had the front tires at 40 psi and the rears at 33. I didnt mess with them too much because it was more for fun that day.

redred
02-05-2013, 03:47 PM
Nice! Have fun!!!

Still love that garage of yours! ;)

shagghie
02-05-2013, 04:59 PM
I ran 48F/45R based on advice from the elder instructors that took her around the course... defo made a HUGE difference. If you fill up the tires before the event, make sure they are very hot with some (Safe) spirited driving. I had mine prefilled to 45/42 on my own prior to track day, but when we measured PSI after my first run they had ballooned up to 54/49! (beyond the max 50 psi spec on the P-zero's). I lowered the rear seats and removed the tire-inflation kit as well. And used blue painting tape to protect the sides of the car from cone marks. If you do get some cone marks, you can use WD-40 to clean them off... soap won't work. :-) Have FUN! and go 'Novice' class so you can get an instructor ride-along or two... make sure they are FWD experienced instructor. Let us know how you do and how your PAX time ended up! Mine was a -4.5s differential, for reference.

rickpike
02-05-2013, 05:33 PM
Looks like we have a couple twins! I just started autocross last summer, had an absolute blast with the Abarth. Started out with instructors, in Novice class. Learned wayyyy more than I ever thought i would. Did 3 last summer and a couple test and tunes.

Just need winter to end here in MN so i can get back out there!

4904

Racerflash
02-06-2013, 10:21 AM
Hey guys, thanks for all the replies and advice. Keep them coming!

Shagghie, are you running the 17" tires with those pressures? I'm assuming all of you are running with ESC full off?

Thanks again
Flash

shagghie
02-06-2013, 12:31 PM
Hey guys, thanks for all the replies and advice. Keep them coming!

Shagghie, are you running the 17" tires with those pressures? I'm assuming all of you are running with ESC full off?

Thanks again
Flash

Yes, the stock 17" wheels and P-zero's. I've kept the PSI the same after the event for a few days now to see how it translates on the street... the front feels a lot stiffer and a bit harsher of a ride (of course) too. I'm going back to stock PSI for my DD this weekend...much better ride and it's not like I'm pushing the edge on my daily commute or rolling tires under! ha.

And YES! ESC Full Off... can't even describe how huge a difference it makes. So much so, I encourage you to 'throw away' one of your runs if you want to see what the car does with it Full On. I did this by accident, as I shut down the engine for a bit in the (long) line... but when I powered it back on, I forgot to turn of ESC mode AND forgot SPORT mode too! I thought I was going crazy out on the course...to the point I wondered if I had a flat tire...the car just pushes so bad in the corners, and the breaking feels like an alien is in control of your rear end.

Racerflash
02-06-2013, 12:40 PM
Yes, the stock 17" wheels and P-zero's. I've kept the PSI the same after the event for a few days now to see how it translates on the street... the front feels a lot stiffer and a bit harsher of a ride (of course) too. I'm going back to stock PSI for my DD this weekend...much better ride and it's not like I'm pushing the edge on my daily commute or rolling tires under! ha.

And YES! ESC Full Off... can't even describe how huge a difference it makes. So much so, I encourage you to 'throw away' one of your runs if you want to see what the car does with it Full On. I did this by accident, as I shut down the engine for a bit in the (long) line... but when I powered it back on, I forgot to turn of ESC mode AND forgot SPORT mode too! I thought I was going crazy out on the course...to the point I wondered if I had a flat tire...the car just pushes so bad in the corners, and the breaking feels like an alien is in control of your rear end.


I can imagine want ESC would feel like on course! When I was test driving the Abarth at the studio, I got a second test drive without the salesman to take my wife for a ride. I went pretty quick through a back road S-turn chicane and it felt like a ghost was grabbing the wheel and taking over the steering! Then I remembered the ESC stability control was kicking in. Not good on an autoX course!

Saxonite
02-14-2013, 08:02 PM
I ran 48F/45R based on advice from the elder instructors that took her around the course... defo made a HUGE difference. If you fill up the tires before the event, make sure they are very hot with some (Safe) spirited driving. I had mine prefilled to 45/42 on my own prior to track day, but when we measured PSI after my first run they had ballooned up to 54/49! (beyond the max 50 psi spec on the P-zero's). I lowered the rear seats and removed the tire-inflation kit as well. And used blue painting tape to protect the sides of the car from cone marks. If you do get some cone marks, you can use WD-40 to clean them off... soap won't work. :-) Have FUN! and go 'Novice' class so you can get an instructor ride-along or two... make sure they are FWD experienced instructor. Let us know how you do and how your PAX time ended up! Mine was a -4.5s differential, for reference.

If I take my car out again to autox this year I'll have to try that and see what kind of difference it makes. My abarth was suppose to be a commuter car, atleast that what I told my wife. lol. It will also be nice after this season to have some people posting their results to get an idea on how to prep the car in stock form for autox. One tip to try is to mark the front tires with window paint where the tread meets the top of the sideway and see if during run the paint on the sideway is gone then add more air and if there is still paint on the tread to take some out. Then adjust the over/under steer by changing the rear tire pressure.

The psi increase from track time doesnt surprise me. I tend to get about 9 psi and 6 psi f/r added during a run. I also get about 2 psi more on the left tires for a clockwise track so each tire starts off about 2-3 psi less as you move front left to rear right. Tire pressures have always been tricky to nail down but once you do it makes all the difference.

shagghie
02-14-2013, 08:40 PM
If I take my car out again to autox this year I'll have to try that and see what kind of difference it makes. My abarth was suppose to be a commuter car, atleast that what I told my wife. lol. It will also be nice after this season to have some people posting their results to get an idea on how to prep the car in stock form for autox. One tip to try is to mark the front tires with window paint where the tread meets the top of the sideway and see if during run the paint on the sideway is gone then add more air and if there is still paint on the tread to take some out. Then adjust the over/under steer by changing the rear tire pressure.

The psi increase from track time doesnt surprise me. I tend to get about 9 psi and 6 psi f/r added during a run. I also get about 2 psi more on the left tires for a clockwise track so each tire starts off about 2-3 psi less as you move front left to rear right. Tire pressures have always been tricky to nail down but once you do it makes all the difference.

Excellent advise and insight. I saw a lot of guys using chalk on their tires and playing with tire pressures for the first one or two runs...

trevc
02-15-2013, 10:56 AM
Looking forward to tomorrow! Unfortunately the predicted high here is 44 F - the Pirellis aren't going to like that..

shagghie
02-15-2013, 12:42 PM
Looking forward to tomorrow! Unfortunately the predicted high here is 44 F - the Pirellis aren't going to like that..

Let us know how it goes! Ironically, the P-Zero's might do better in the cold than even the Yoko AD08's would, for example. Grip for everyone will be down, at least. Not sure about your location, but here in So Cal we are not allowed to 'warm up' the tires (burn outs). But might be a strategy for you if it is allowed there...just know the rear end won't be as grippy as the front. Others might know here....but I wonder if on cold days whether tire pressures should be kept relatively higher or lower compared to warm days?

redred
02-15-2013, 01:35 PM
Tire pressure will go up, even in colder temps. Just might not go up as high or as quickly. Tire temp doesn't increase from road friction. It increases from the heat transfer from the brakes. It's all one big heat soaking metal piece. The pads heat up the rotors. That heat transfers thermally to the tires, but also transfers via all the metal contact: rotor > lugs > wheel. What we were told to do at Streets of Willow last month was to do the first few laps with the tires set to their normal suggested pressure: 38 in front, 32 in back. Then at the end of the first round of laps, check the tire pressure again as soon as you can. My pressure went up quite a bit and I then lowered it back down to 38 in front and 32 in back. Keep checking your tire pressure immediately after you stop your run. That will give you the best indication of how the tires are running on the track.

Just a note: the day we went with Road Race to Streets of Willow, the temp when I arrived was 17 degrees!!! It was freaking cold! I was running the stock Pirelli 16's and after they warmed up the grip was so-so in the cold. The guys running the P-Zero's stated they had better grip. Road Race was running Toyo R888's Proxes and they had a real hard time with grip until the day warmed up a bit.

Definitely make sure you take a tire pressure gauge with to the x-cross date! Also, a torque bar wouldn't be a bad idea as well with a 17mm deep socket. You'd be surprised how much the lugs can let go from all that heat generated from the hard braking you will be doing!

BigDaddySRT
02-15-2013, 01:47 PM
Tire pressure will go up, even in colder temps. Just might not go up as high or as quickly. Tire temp doesn't increase from road friction. It increases from the heat transfer from the brakes. It's all one big heat soaking metal piece. The pads heat up the rotors. That heat transfers thermally to the tires, but also transfers via all the metal contact: rotor > lugs > wheel.....

Ummmm... I don't know what Kool Aid you've been drinking, but Tire Temperature has everything to do with Road Friction.

shagghie
02-15-2013, 01:54 PM
I thought stock recommended was 38/38 psi. Where I settled on auto-x day was 48f/45r (hot temp just after a run). The road friction is defo where the heat comes from. There's a few drivers out there that don't even use the breaks (crazy I know!) on the run. I could see how long/deep breaking on a race track would heat up the tires additionally, but the breaks don't seem to ever get that hot on Auto-X. Now, the real challenge is to keep the driver cool. Calm, smooth and cool. I find I heat up WAYYY too fast! :-p

redred
02-15-2013, 02:19 PM
Ummmm... I don't know what Kool Aid you've been drinking, but Tire Temperature has everything to do with Road Friction.

Ok then... well we will just agree to disagree then. Road friction is a contributing factor, but not the only one.

BigDaddySRT
02-15-2013, 02:48 PM
Ok then... well we will just agree to disagree then. Road friction is a contributing factor, but not the only one.

To prove my point even more...


https://www.youtube.com/watch?v=272zDtbhK48

redred
02-15-2013, 03:19 PM
That's fascinating and everything, but that is a Nascar race. Slightly different scenario to an auto-cross. Different speeds, tires (ie: slicks), driving styles, etc. I am referring to an autocross day with our Abarth and stock tires. Extreme braking will contribute to the heat of the tires.



I thought stock recommended was 38/38 psi.


Perhaps that is the case with the 17's? In my car, the Tire & Loading information label in the door pillar states 38F and 32R


http://i282.photobucket.com/albums/kk263/staceydodds/file_zps3ca9cac6.jpg

BigDaddySRT
02-15-2013, 03:36 PM
That's fascinating and everything, but that is a Nascar race. Slightly different scenario to an auto-cross. Different speeds, tires (ie: slicks), driving styles, etc. I am referring to an autocross day with our Abarth and stock tires. Extreme braking will contribute to the heat of the tires.

Tires are Tires... Heat is generated in the Tire due to the Friction between the Tarmac and Tire Compound.

Just because your Brakes are hot doesn't not mean that your tires are at Hot.
The Brake Pads/ Rotors do not transfer heat into the Tire Carcass.


Tire Heat is generated by the Friction between the Tarmac and the Tire Compound.

redred
02-15-2013, 04:57 PM
The Brake Pads/ Rotors do not transfer heat into the Tire Carcass.

Like I said. I will agree to disagree.

Saxonite
03-01-2013, 03:00 PM
I agree with redred. While the brakes aren't the main factor in heating the tires, there will be some heat transfer from the brakes to the tires. If you touch your rim after repeated hard braking you will notice that it is hot and that heat will transfer itself to the tires by being in contact with each other. Also your brake pads and discs can reach up to 1000 degrees on most performance production cars and production cars typically are very poor at venting the air out of the wheel well and that will build in heat from the brakes as well. Your brakes are just simply too close to the tires for them to not have an effect on tire temps. It won't be a lot but probably 10-15 degrees.