Rattsl Posted April 30, 2015 Author Share Posted April 30, 2015 So the days are closing in, and I have a few things in mind before I go out there like a noob (who am I kidding, right?). I saw BMB posting on a thread somewhere about tire pressures (each case is different to different tire size etc) and I'm curious as to how to go about that. Would I be gauging it off of weather, not even care about it, or some secret formula out there, or say eff it and run 10psi on all 4's are pray for the best I'm still on 215/45/17's which is stock tire size, and I believe those are 33 front and 35 rear, something like that. Would I go up in pressure to accelerate quicker, yet, lose grip on turns, or add more pressure to the rears and less to the fronts? (I have no idea what I'm talking about) Any help would be great. Thanks, Link to comment Share on other sites More sharing options...
whitetiger Posted April 30, 2015 Share Posted April 30, 2015 I forget what tire brand/model you said you are on, but you want enough pressure to prevent roll-over. My rule of thumb is to start at 40psi, with the sidewall chalked and start letting out some air after each run to see if grip increases, but not too much that the tire starts rolling over and rubbing off the chalk. Since all tires are different, some may like a lot higher pressure than others. if you are just running a mediocre summer cruising tire, it generally will want more PSI since the sidewalls will be soft. Link to comment Share on other sites More sharing options...
Rattsl Posted April 30, 2015 Author Share Posted April 30, 2015 I'm running a ....mediocre UHAPS tire (Nitto Motivo) for now, so starting at 40psi wouldn't be an issue. I will set my suspension to a stiffer setting once I'm there, and maybe play around with pressure later into the day. Link to comment Share on other sites More sharing options...
whitetiger Posted April 30, 2015 Share Posted April 30, 2015 those tire are garbage. leave the suspension alone. Set it in the middle and drive it. play with tire pressures first. Link to comment Share on other sites More sharing options...
Rattsl Posted April 30, 2015 Author Share Posted April 30, 2015 I'll try that out. Link to comment Share on other sites More sharing options...
Rattsl Posted May 4, 2015 Author Share Posted May 4, 2015 So, I'm back from autox. I'm hooked. http://images.tapatalk-cdn.com/15/05/03/aa778f1698dd8e333166585872c3f30a.jpghttp://images.tapatalk-cdn.com/15/05/03/e8ce0a4bed63ed7d72f75ba57cad7189.jpghttp://images.tapatalk-cdn.com/15/05/03/8a850c558769a6dfafe261a94f2e6507.jpg Things I noticed. My tires suck major ass. Looking at something more dedicated. May look for spare wheels. My brakes did fine, so I can't imagine how nice stainless lines and brake booster brace would be. I ran 30 psi in my tires by the end, but had understeer. I'll be doing more suspension tuning and stickier tires. Link to comment Share on other sites More sharing options...
StoplightAssassin Posted May 4, 2015 Share Posted May 4, 2015 Understeer is always going to be there in a car with the engine mounted in front of the front axle. You'll learn to drive around it. Link to comment Share on other sites More sharing options...
Rattsl Posted May 4, 2015 Author Share Posted May 4, 2015 I figured, nicer tires would help a lot. Link to comment Share on other sites More sharing options...
boxkita Posted May 4, 2015 Share Posted May 4, 2015 cant say enough about a dedicated set of wheels/tires plus pads/rotors. I had all that for lapping and it was nice to drive street performance on the road and "full race" at the track. Build my car Boxkita Track days Link to comment Share on other sites More sharing options...
whitetiger Posted May 4, 2015 Share Posted May 4, 2015 Things I noticed. My tires suck major ass. Looking at something more dedicated. May look for spare wheels. I'll be doing more suspension tuning and stickier tires. I told you your tires were garbage. In ASP you are gonna want hoosier A7, but if you need to stick with a street tire, the Bridgestone RE-71R is the current tire of choice in ST. Link to comment Share on other sites More sharing options...
Rattsl Posted May 4, 2015 Author Share Posted May 4, 2015 I'll search those up. I'm figuring out what size would be good on my car. Link to comment Share on other sites More sharing options...
whitetiger Posted May 4, 2015 Share Posted May 4, 2015 ^as wide as you possibly can fit. I was able to do a 255/35/18, but it was tough. you will need some prerequisite parts and a precise wheel offset to make it work. Also if you are truly hooked on autox, and want some consult on what you need to make your car as competitive as possible, PM me and we can work on a very targeted setup. Link to comment Share on other sites More sharing options...
Rattsl Posted May 13, 2015 Author Share Posted May 13, 2015 So, I managed to get a low mileage VF52 and a Perrin inlet for it. I will be looking down the road for a TMIC, and if the same seller still has his Perrin TMIC, I may snag that as well. Also, discussing elsewhere, I was being told that a stiffer rear suspension setup and softer front will help the car oversteer rather than understeer. Any fact to this? Link to comment Share on other sites More sharing options...
whitetiger Posted May 13, 2015 Share Posted May 13, 2015 ^don't get the turbo, it will put in Street modified class, and you will never be competitive there. Do a TMIC though. If you have understeer issues, BUY BETTER TIRES understeer = a loss of front end grip. thats what you need to focus on, putting grip at the front end. if you make the rear stiffer, you will reduce rear grip, not make the front grip more. you only do this if you are playing with balance, but that's after you have dealt with tires. Dont put the cart before the horse. If you make the car more twitchy, if will be harder to control at the limit and you will not learn to drive better. Link to comment Share on other sites More sharing options...
StoplightAssassin Posted May 13, 2015 Share Posted May 13, 2015 Also, discussing elsewhere, I was being told that a stiffer rear suspension setup and softer front will help the car oversteer rather than understeer. Any fact to this? Lots of fact, although you don't want oversteer. You want your car to be neutral. Very few autocrossers that I've seen set their Subies up to oversteer. Whatever set of springs you have is already softer in the front than rear. Link to comment Share on other sites More sharing options...
whitetiger Posted May 13, 2015 Share Posted May 13, 2015 talk of suspension changes/tuning is meaningless until the right tires are bought. Link to comment Share on other sites More sharing options...
StoplightAssassin Posted May 13, 2015 Share Posted May 13, 2015 Everything is meaningless until we get a class nailed down. Link to comment Share on other sites More sharing options...
whitetiger Posted May 13, 2015 Share Posted May 13, 2015 well, it definitely wont be Street Mod. Rattsl should keep the stock turbo and play in ASP, or just to a STX tune and stay in STX Link to comment Share on other sites More sharing options...
Rattsl Posted May 13, 2015 Author Share Posted May 13, 2015 I raced ASP already. Link to comment Share on other sites More sharing options...
whitetiger Posted May 14, 2015 Share Posted May 14, 2015 we know. you are only in that class because of your stage 2 tune. If you get good at autox, you are gonna want to be in a somewhat competitive class right? Link to comment Share on other sites More sharing options...
whitetiger Posted May 14, 2015 Share Posted May 14, 2015 FWIW, the amount of money you will spend on that vf52 and TMIC will more than cover for a set of amazing autox duty street tires. that needs to be your next mod. still on 17 rims - get these http://www.tirerack.com/tires/tires.jsp?tireMake=Bridgestone&tireModel=Potenza+RE-71R&sidewall=Blackwall&partnum=245WR7RE71RXL&tab=Sizes the best/stickeiest 200tw tire you can get. it will transform the car and push the limit far beyond what a novice can drive. this means say goodbye to understeer as you know it, and say hello to grip. Link to comment Share on other sites More sharing options...
Rattsl Posted June 17, 2015 Author Share Posted June 17, 2015 So, this Sunday is another race day, and it may rain, but I'm gonna have to do a few things before. I will be adjusting my front camber to near almost -2.0 degrees and leave the rears around -1.5 just to see what it feels like. I am yet to install any of the turbo upgrades, but I'm going to hold on to those for when it's needed as a maintenance item. Last time I noticed I had tons of tire roll over, so I will not only adjust camber, but run a stiffer setting for rear suspension and softer up front. Tire pressure, I may do F30 R35. Only want to do this so the rear end can be picked up a little easier. (in theory) Thoughts? Link to comment Share on other sites More sharing options...
Sgt.Gator Posted June 17, 2015 Share Posted June 17, 2015 So, this Sunday is another race day, and it may rain, but I'm gonna have to do a few things before. I will be adjusting my front camber to near almost -2.0 degrees and leave the rears around -1.5 just to see what it feels like. I am yet to install any of the turbo upgrades, but I'm going to hold on to those for when it's needed as a maintenance item. Last time I noticed I had tons of tire roll over, so I will not only adjust camber, but run a stiffer setting for rear suspension and softer up front. Tire pressure, I may do F30 R35. Only want to do this so the rear end can be picked up a little easier. (in theory) Thoughts? A tiny bit of toe out in the front is good for autoX, bad for a race track. You can experiment with an 1/8" toe out on the front. I know a guy who runs so much toe out on the front and back of his dedicated autox car he can't drive it on a track at all. You likely need a lot more air for your street tires. Buy some chalk sticks, put 4 marks around the circumference of your tires running from the tread down the sidewall. You have enough air when the chalk rubs off the tread marks but the sidewall ones don't. That will tell you howfar down the sidewall you are running. Nothing like a race track to find the weak points in man and machine. "Good Judgement comes from Experience. Experience comes from Bad Judgement" Link to comment Share on other sites More sharing options...
Rattsl Posted June 17, 2015 Author Share Posted June 17, 2015 Buy some chalk sticks, put 4 marks around the circumference of your tires running from the tread down the sidewall. You have enough air when the chalk rubs off the tread marks but the sidewall ones don't. That will tell you how far down the sidewall you are running. I sorta do that already only with a bit of a different method. I painted the letters on my tires white, and that gave me a great idea of how much sidewall was being eaten up by hard turn ins. Not only does it look cool (think classic white-lettered tires on cars in the late 60's to early 90's) but it also gauges the sidewall well. Link to comment Share on other sites More sharing options...
Rattsl Posted June 17, 2015 Author Share Posted June 17, 2015 Another thing I was going to mention was, would it be a bad idea if I bought a bag or two of ice, and after a heat, place said bag of ice on tmic? I usually just pop the hood and let it breathe, but figured cooling the tmic to a lower temperature would be nice. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.