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ccsouls
03-23-2009, 07:29 PM
Does anyone know of a good educational chart or something to assist in adjusting air pressures in tires when racing relative to outsite air and road temperatures?

I had a horrible showing in my first 2009 autocross last weekend because I could not get the fracking tires pressured correctly to get grip.

When I changed the wheels out last night, the wear indicators were still well short. I was WAY off and it hurt my times badly.

In the cold, I won the final 2 2008 races with 45 lbs in the front and 40 in the back. Great grip.

However last weekend, that same setup was getting me WELL over 50 lbs in the heat and I could not get enough air out to get the grip right. (Dunlop Dizzaras.)

I know some of you have to know how to teach me this. KoreanJoey I know has a similar (but better) setup to what I am doing.

Please help.

Thanks everyone.

(Bilstien shocks, Eibach Pro-kit springs, 27mm front swap, 22mm rear sway, twosrus endlinks)

KoreanJoey
03-24-2009, 06:22 AM
Really, it's all going to come down to testing, generally speaking I'll run the pressures as low as I can while the tires not folding, the response will be slower but at the same time that roll in the sidewall helps generate heat, which I desperately need with 33-35degree track temps.

At higher temps I'd run higher pressures as it'll create less heat. Also, you can cook your tires, the Direzzas get up to temp super fast so I'd watch for that. Maybe bring out a sprayer to hose down the tires.

Maybe invest in a tire pyrometer and contact Dunlop to see what they rate the optimum operating temp is for the Direzzas.

(Hankook RS-2s are in the range of 70-110, the Hankook Z214s are 160-220).

ccsouls
03-24-2009, 04:27 PM
Thanks Joey.

While I have you reading this, does your inside rear tire come off the ground in corners?

I am getting grief from everyone telling me I need to get that wheel back on the ground if I want to get better traction, but I keep reminding then that until I got the car tripoding it had a bad understeer. At least now it turns in like I need it too.

I would really appreciate reading your ideas on the "inside rear off the ground" and if it is possible to get it back on the ground and still get the car to turn in (and what you might have done to accomplish that).

Thanks.

KoreanJoey
03-25-2009, 02:31 AM
Thanks Joey.

While I have you reading this, does your inside rear tire come off the ground in corners?

I am getting grief from everyone telling me I need to get that wheel back on the ground if I want to get better traction, but I keep reminding then that until I got the car tripoding it had a bad understeer. At least now it turns in like I need it too.

I would really appreciate reading your ideas on the "inside rear off the ground" and if it is possible to get it back on the ground and still get the car to turn in (and what you might have done to accomplish that).

Thanks.

Mine still lifts on hard corners. Honestly, I'm ok with it as I like the oversteer created by the single wheel in the back on harder corners. **shrug**

Honestly, VWs have been doing it forever and with our crappy weight balance it's going to be hard to alleviate without seriously jacking up the cornering of the car.

It's a nose-heavy FWD car, you have to get it to rotate...

Slider
03-25-2009, 03:09 AM
Nothing wrong with a little lift :sneak:
http://www.celicatech.com/gallery/files/6/0/1249231637_2a9cc93497.jpg
KoreanJoey's looks way more ridiculous with those sticky tires.

KoreanJoey
03-25-2009, 07:05 AM
Nothing wrong with a little lift :sneak:
http://www.celicatech.com/gallery/files/6/0/1249231637_2a9cc93497.jpg
KoreanJoey's looks way more ridiculous with those sticky tires.

Yeah back in the day w/ stock springs and just Koni Yellows on Kumho V710s.

http://www.celicatech.com/gallery/files/3/6/5/47b6d734b3127cce9854c281a48300000007109AatGThwzaA. jpg

donteatbugs
03-25-2009, 12:12 PM
lol....we have a mazda 3 hatch that lifts it rear wheel and was still the fastest in hs and in high competition in sts now.

this past weekend we had a m3 that is race prepped lifting his front wheel!!!! that was cool

ccsouls
03-25-2009, 01:40 PM
Holy Crap Joey! I feel WAY better now.

Mine lifts, but NOTHING like that! My goodness. :)

Mine looks more like Sliders, but not as much body role.

I tend to agree. With these cars you almost have to let it come up to get the rear to come around the way it needs to.

I just need to really test the pressure issue. I think that has to be the main issue with me. I simply messed up and didn't adjust for the hotter track and therefore had WAY too much air in my tires.

If I was able to win with this setup last year, I know it has to work if I get the pressures correct (and I don't drive like an idiot).

Thanks everyone. I appreciate the input.

Blackcloud
03-30-2009, 12:51 AM
i dunno if we figured ours correct in the vette right or not... we just looked at the sidewalls to see how much they rolled, and adjusted accordingly

KoreanJoey
03-30-2009, 06:40 AM
Holy Crap Joey! I feel WAY better now.

Mine lifts, but NOTHING like that! My goodness. :)

Mine looks more like Sliders, but not as much body role.

I tend to agree. With these cars you almost have to let it come up to get the rear to come around the way it needs to.

I just need to really test the pressure issue. I think that has to be the main issue with me. I simply messed up and didn't adjust for the hotter track and therefore had WAY too much air in my tires.

If I was able to win with this setup last year, I know it has to work if I get the pressures correct (and I don't drive like an idiot).

Thanks everyone. I appreciate the input.

Again, make sure the tires themselves aren't overheating.

ccsouls
03-30-2009, 02:35 PM
I felt the tires by hand after each run, and although I know that is not the best way to tell, they did not seem unusually hot to me.

Checking the wear indicators is how I knew I was WAY off last race. I just did not have a way to put air back in so I was too conservative in letting it out between runs and never got it low enough.

I plan to purchase a tank to take with me to this weekends race and hopefully I will be able to get it right this time.

Thanks.

RedRkt01
05-08-2009, 02:43 AM
How do you guys feel about the use of nitrogen in tires as opposed to air? Nitrogen excludes the possibility of of pressures fluxing with temperature. I like the idea.....that way you know that no matter what your pressures are always at what you set them.....no +/- factor.

Grot
05-08-2009, 03:29 AM
I know i heard one negative thing about nitrogen that made me never want to use it, i cannot remember what it was.

Might have been extreme dry rotting issues, i cant remember though.

RedRkt01
05-08-2009, 03:30 AM
I can't imagine that being the case. But I would like you to find out what made you think that way (for sure) and report back.

Grot
05-08-2009, 03:40 AM
will do.

RedRkt01
05-08-2009, 03:55 AM
thanks mate

Grot
05-08-2009, 04:21 AM
Here (http://www.thetruthaboutcars.com/the-truth-about-filling-your-tires-with-nitrogen/) is what i found.

Cliffs: If you check your tire pressure once a month. N2 is not worth your money.

I cant remember what it was i heard still, but this makes me not want to waste my money one it.

RedRkt01
05-08-2009, 02:31 PM
I have access to it in bulk......so thats pretty much an affirmation for me. Since you don't I don't blame you.

ciento44
05-08-2009, 02:38 PM
CCSouls, which direzzas do you run... the Star Specs?

ccsouls
05-08-2009, 03:03 PM
Yes.

Direzza Sport Z1 Star Spec.

So far, I like them alot. They do very well in the wet also.

However this tire pressure thing seems real important with them. I have about figured them out now, but still adjusting for outside track temps.

In my class 140 is the lowest rating I can use so these work well and are a good value.

KoreanJoey
05-13-2009, 08:31 AM
Yeah right now I'm thinking I might have to sacrifice tire width for a smaller diameter... PS: Right now the only tire company I see paying out for both ProSolos and NTs are Toyo...

I might pick up a set of 215/45R15s as I compete better in ST than I do in NS3(CSP, DSP and FSP all grouped together and then indexed).

*shrug*

ccsouls
05-13-2009, 03:03 PM
I just bought an All-Trac and am considering just how wide I should go with it since it will be an autocross car only.

I know 8 inch wheels are supposed to fit them without issue. However, I am still thinking of going with a 7 inch for weight reasons.

Any comments?

ciento44
05-13-2009, 03:43 PM
I just bought an All-Trac and am considering just how wide I should go with it since it will be an autocross car only.

I know 8 inch wheels are supposed to fit them without issue. However, I am still thinking of going with a 7 inch for weight reasons.

Any comments?

The weight difference between a say 17x7 and a 17x8 when talking about good wheels is negligible to the point that the extra rubber you can run on a 17x8 would FAR offset the weight penalty.

My 16x8s weigh 15lbs a pop. I wasn't too interested in sacrificing back down to 215 or 225 width to save 4lbs.

Honestly? I think you should go wider than 8s. :D

I can run 245 width on 16x8s on a narrowbody. You have an alltrac. USE IT! ;)

And to be real picky, with the extra clearance i now have, i've calculated that i could possibly fit 255 with my current setup with a very slight flair in the back. If i got a higher offset wheel, i could fit 265. You gain a TON of clearance with aftermarket suspension depending on company. I picked up almost 15mm going from stock rear struts to the Megan Racing units.

And this is still a narrowbody.

ccsouls
05-13-2009, 03:54 PM
Were did you find 16x8s weighing 15lbs? Did you break down and by Volks?

That is my ideal setup, but I was considering the 17s because it appeared tires for the 17s were more readily available than the 16s. Do you have any problems finding tires?

My SCCA class for the All-Trac (STX) limits wheel size to 8 inches and tire width to 245 mm, so that is as wide as I can go for now.

I also have the Megans and could go larger, but I am limited for now.

ciento44
05-13-2009, 04:04 PM
Were did you find 16x8s weighing 15lbs? Did you break down and by Volks?

That is my ideal setup, but I was considering the 17s because it appeared tires for the 17s were more readily available than the 16s. Do you have any problems finding tires?

My SCCA class for the All-Trac (STX) limits wheel size to 8 inches and tire width to 245 mm, so that is as wide as I can go for now.

I also have the Megans and could go larger, but I am limited for now.

The Enkei RP01s are LIGHT, dude. (i guess they're technically 15.2lbs or whatever) :D Grassroots Motorsports forums general consensus seems to be that the RP01s are one of their favorite enkei wheels ever for that reason.

As for tires..... the only "wide size" that i've found readily available are 245/45-16. There's a decent selection out there. If you deviate from that, good luck. Not much there.

17s tire selection is much better, but i've even had a hard time finding anything that would work if i wanted to go wider in the 17" size.

I'm running RS2s again, i haven't found if the RS3s are going to be in that size or not yet. I believe the RE11s come in that size, and i thought the new XSs as well. Don't know bout the Direzzas. You can get the RT615s in that size, but as far as i'm concerned, their time has past.

But.... if you're limited to 245 width, i'd just go 16s if that's what you want. Start searching Ebay for used Enkeis, OZs and the like. You may also be able to get Rota to make you a set of Slips with the right offset. I paid $350 shipped for my wheels. One did need a repair at $125 to take out a bend, but end price of $475 for a set of functional wheels that cost $370 apiece when new with the offset that i NEEDED? I think i'm ok with it.

ccsouls
05-13-2009, 04:10 PM
Sweet!

I have always been of the mindset that a fare sidewall was better for racing which is why I wanted to go with 16s instead of 17s, but as I look at the Speed World Challange cars, they do not have very much sidewall so perhpas that sentiment is not as relavent.

If that is true, then 17s should work just as well as 16s for SCCA use and offer more tire choices.

Thanks for the input. I do appreciate it.

KoreanJoey
05-13-2009, 04:15 PM
I run 16x7.5 and they weight around 11lbs.

I run SSRs Ben runs Enkeis, Koseis are also very light, or Volks or Gram lights, hell, even Rotas are light.

ciento44
05-13-2009, 04:21 PM
Honestly, i wanted 16s from mostly a looks standpoint, and the fact that i didn't really want to go to a 35 or 40 sidewall. That's really about it.

The tire selection in 17s, say.... 245/40-17 is FAR better than 245/45-16. But as long as someone makes a decent 245/45-16, i'll stay with the current setup, because it's simpler for me. My only other reason for wanting 17s is to run some huge brakes, which in my ~2300lb car, isn't really necessary. Plus, i can run some MONSTER calipers with these wheels as it is.

I wonder if i would still be in STX.

I was going to run Winged Warrior V this past weekend, but they were going to lump me in "Top Gun" against the vipers, procharged vettes, 9 second Evos, and crap like that, because of my "mod list" and the fact that it's a fairly stripped interior. Never mind that the car might make 80whp. :hehe:

ciento44
05-13-2009, 04:22 PM
I run 16x7.5 and they weight around 11lbs.

I run SSRs Ben runs Enkeis, Koseis are also very light, or Volks or Gram lights, hell, even Rotas are light.


Mmmmmmmmm Kosei K1s.... TASTY. If i ever upgrade i'll probably go to those.

ccsouls
05-13-2009, 04:35 PM
I had the same problems with my GT.

They had me in SM with all the same cars you listed and it was more about how much money you could spend than it was about skill.

That is the "straw" that made me splurge for the All-Trac. Yes, I wanted it anyway, but getting a competitive class was the final straw.

I will still get trouble from the BMWs and the Minis, but at least I have a chance now (and a good PAX).

ciento44
05-13-2009, 04:42 PM
I had the same problems with my GT.

They had me in SM with all the same cars you listed and it was more about how much money you could spend than it was about skill.

That is the "straw" that made me splurge for the All-Trac. Yes, I wanted it anyway, but getting a competitive class was the final straw.

I will still get trouble from the BMWs and the Minis, but at least I have a chance now (and a good PAX).

I think if i can get them to look past the lack of interior, i would stay in STX, since i'm still rocking a stock motor this season.

But i'm not exactly competitive in STX, either. :p

Which trac did you get?

ccsouls
05-13-2009, 04:50 PM
I got the 1990 red one previously owned by "Turbo Lean" on alltrac.net.

Pick it up Friday.

Very excited. Already have it entered in the Pro Solo June 6th & 7th, but I have some slight "modifications" to make before the event.

He has a front mount intercooler which has to come off, but other than that and some end links and rear strut tower bar I will be ready to go.

I have a spare AWD tranny I will put on also before the event to "freshen up" the one he has. :)

ciento44
05-13-2009, 04:58 PM
I got the 1990 red one previously owned by "Turbo Lean" on alltrac.net.

Pick it up Friday.

Very excited. Already have it entered in the Pro Solo June 6th & 7th, but I have some slight "modifications" to make before the event.

He has a front mount intercooler which has to come off, but other than that and some end links and rear strut tower bar I will be ready to go.

I have a spare AWD tranny I will put on also before the event to "freshen up" the one he has. :)

Pro-solo where? I think i may be running up at Tire Rack those dates, hopefully with Slider.

I saw that car... nice score!

Oh... and you have PM. ;)

ccsouls
05-13-2009, 05:09 PM
This one is in Blytheville AR the weekend immediately following the Eastern States Pro Solo Championship there.

I will be in the EVO Phase 1 School the weekend before, then the solo that weekend.

Thanks for the "nice score!". I am excited.

I don't have a PM? What are you referring to? (Sorry if I should know that :) )

ciento44
05-13-2009, 05:22 PM
This one is in Blytheville AR the weekend immediately following the Eastern States Pro Solo Championship there.

I will be in the EVO Phase 1 School the weekend before, then the solo that weekend.

Thanks for the "nice score!". I am excited.

I don't have a PM? What are you referring to? (Sorry if I should know that :) )


I was still typing it in another window. ;)

And now your PM box is full, so i can't reply. Wasn't anything important, i'll just wait for your status update PM. :D

ccsouls
05-13-2009, 05:23 PM
I made some room.

Sorry.