Need autocross help, advice

Discussion of LEGAL Vibe & Matrix racing events, autocross, drag racing, closed track road racing, and technical racing aspects. [Disclaimer]
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CountryVibe
Posts: 310
Joined: Fri Feb 23, 2007 11:41 am

Need autocross help, advice

Post by CountryVibe »

I went to autocross today for the 3rd time. Where the S.C.C.A. chapter setups is a helicopter stage field. The surface concrete and you don't get the same traction as you do on asphalt. The problem I am having is bad wheel spin coming out of the turns even in third gear I am still getting the wheel spin and feel like I am losing time when it happens. It seems like even with just a little gas It wants to spinWhat came I do to fix is?thanks for the help
2005 GTmoons & tunes, keyhole covers, SRI,2.5" borla catback exhaust, seatbelt beep deletedWagons Rule.......Sedans Drool
northvibe
Posts: 7641
Joined: Tue Jul 05, 2005 2:25 pm

Post by northvibe »

to keep tires on pavement you can, lower the vibe, get motor mounts, anti sway bars, strut tower bar, new tires.....could be a couple more mods but Ive never autox'd before those are just what i know to keep your car on the ground.
manicdan
Posts: 160
Joined: Fri Oct 27, 2006 5:08 am

Post by manicdan »

tell us about your setup. what kind of tires are you using. how stiff is your suspension. mechanical limits are about 60% tires, 30% body roll and 10% power. everyone says the driver is most important, but u cant quite tell how good you should be unless someone else shows you what your car can do.one thing thats a quick misconception is that on a track those turns might look big but there really not, so while on the road u might make a sharp turn at 30, on the track its actaully much smaller and can only be done at 25. one thing thats hard to grasp but is simple to understand in how to properly prepare your car for every turn. either your pressing on the gas or pressing on the break, never coasting. and your pressing hard. when going to a turn slam those brakes and go way slower than you need to. sure it will waste some time but your car will acelerate through the first part of the turn till your at the speed you should be at then start sliding out. you know that when you hear your tires screeching. so let go of the gas just a bit as you maintain that speed till your almost through the turn, then press hard again and speed up to the next turn.thinking that you can enter a turn at the right speed is what we need to keep out of our head, you catch onto that with lots and lots of experience. so going in slow is much better than going in fast and having no grip to pull you through. you can test this out in many video games where it shows your ghost as the opponent, complete one lap braking extra hard and the next going in just a tad fast, you should see yourself being passed and as you leave he will be going much faster than you and you never catch up.hope this helps a bit
Kamikaze
Posts: 2017
Joined: Wed Aug 15, 2007 9:36 pm

Re: (northvibe)

Post by Kamikaze »

I don't know what you all have done to your ride, but probably your first and best thing you could do is get a set of track tires, something like: Kumho VictoRacer V700's. These are the tires that I used when I autocrossed. setup of the suspension is another crucial topic But I understand that if you're doing this at your leisure, and not setting the car up as track only you will suffer ride ability for every day driving.If you want to play witht the suspension (after tires) you can go a few different ways, you could do just springs, lowering the car and having stiffer springs would help, but you wouldn't have much adjustability. You coud do a coilovers, and swap out the struts for adjustables, then you could adjust how soft/hard your rebound is going to be. after playing with that, you could get into the anti sway bars, negative camber, strut tower stuff, the strut tower bar isn't going to do all to much with your wheel spin, it's more to do with body roll, (yes it would make some difference, but probably so little over doing all of the other things)lastly, you coud do a limited slip Diff, (I don't even know if they make it for the vibe) but that would probably stop your wheel spin issues. it wouldn't be cheap.
August 2009 VOTM Click HERE for my Garage
Kamikaze
Posts: 2017
Joined: Wed Aug 15, 2007 9:36 pm

Re: (Kamikaze)

Post by Kamikaze »

I just wanted to also say that manicdan has it right. I've seen guys with stock suspension come into a corner totally different than a slammed car, and leave faster. how do they do it? They pre-load the suspension before the corner by acutally tapping the brakes hard, loading up the suspension, and as they exit the corner they have the force of the preloaded suspension working with them. this with coming into the corner not so hot allows for them to cleanly exit the corner at a higher speed because they can start accelerating earlier thru the corner.
August 2009 VOTM Click HERE for my Garage
CountryVibe
Posts: 310
Joined: Fri Feb 23, 2007 11:41 am

Post by CountryVibe »

My GT is mostly stock right now only upgrade I have is a Short Ram Intake, the tires I have are toyo proxy 4, during the last 2 times i raced i had some ride with me to help with the tire pressure. I am running 45psi on the fronts and 40psi in the rear. When I had the tire lowered they wanted to fold under themselves in the turnsI mostly run in second gear and usually try to make sure that if it's a fast turn I shift so the car will not hit the lift coming out of the turn They usually put in a quick s turn on one of the runways because there is tons of room if someone spins out
2005 GTmoons & tunes, keyhole covers, SRI,2.5" borla catback exhaust, seatbelt beep deletedWagons Rule.......Sedans Drool
CountryVibe
Posts: 310
Joined: Fri Feb 23, 2007 11:41 am

Re: (CountryVibe)

Post by CountryVibe »

Quote, originally posted by Kamikaze »lastly, you coud do a limited slip Diff, (I don't even know if they make it for the vibe) but that would probably stop your wheel spin issues. it wouldn't be cheap.I was thinking of a LSD but I didn't have much luck finding one online for the Vibe
2005 GTmoons & tunes, keyhole covers, SRI,2.5" borla catback exhaust, seatbelt beep deletedWagons Rule.......Sedans Drool
Kamikaze
Posts: 2017
Joined: Wed Aug 15, 2007 9:36 pm

Re: (CountryVibe)

Post by Kamikaze »

Your Toyo's probably have a treadwear rating between 3-400, A race tire is going to be somewhere between 50-100 (usually the lower the # the more grip, but the faster the tire will wear out)The Victoracer's are 60, After racing with these tires both my friend and I swear we'll never go back to street tires when doing the Solo II events. The amount of grip is INSANE compared to the tires we ran on the street at 200 (treadwear)We've raced both on actual tracks, and airport fields (all concrete) the difference on either surface was huge.I sold my car and now I just use my bike as my fun toy, street and track.
August 2009 VOTM Click HERE for my Garage
northvibe
Posts: 7641
Joined: Tue Jul 05, 2005 2:25 pm

Post by northvibe »

theres 2 lsd's i think...maybe 3. TRD makes one, quaife and there may be one more goofy named brand...http://monkeywrenchracing.com/....htmltheres the quaife, its the big brand named one.. problem is they cost 1200+ for the part alone...
Mavrik
Posts: 8072
Joined: Sat Jan 03, 2004 6:41 am

Re: (northvibe)

Post by Mavrik »

I found what helped to keep my Vibe's wheels on the ground when I autocrossed SCCA last season was Tein springs, rear sway bar and front strut bar. Only time I'd really slid out, understeered and what not was due to vehicle speed or not racing the right line. Also the right front wheel liked to lift up and spin when making tight right turns. If you have optional direction, always turn left to keep that wheel on the ground.I never hit 3rd gear though... course/car wasn't that fast.
2007 stage 2 Satin White Pearl Subaru STi 2008 stage 2 Subaru STi hatch See my car at: Mavrik's car page
CountryVibe
Posts: 310
Joined: Fri Feb 23, 2007 11:41 am

Post by CountryVibe »

Thanks for the help guys I know what mods to put in the top of list to get now. hopefully i can get a few before next's months meetI am still debate-ing about the LSD I wanted to upgrade the clutch soon and was thinking of adding it while the trany was out
2005 GTmoons & tunes, keyhole covers, SRI,2.5" borla catback exhaust, seatbelt beep deletedWagons Rule.......Sedans Drool
AKLGT
Posts: 11694
Joined: Thu Apr 24, 2003 2:57 pm

Post by AKLGT »

before going all out with the LSD, i would do TIRES!!!! and performance springs, rear sway bar and a strut bar. if you don't have these, the LSD still won't help your body roll. plus, you may be understeering around some of the corners causing you to lose time. (i know all about understeer!). also, i would recommend upgrading your brakes/pads. if you have better brakes, you can go a little faster and slam on those brakes to slow you down for those turns.
AKLGT1998 Subaru 2.5RS
manicdan
Posts: 160
Joined: Fri Oct 27, 2006 5:08 am

Post by manicdan »

with a short ram you cant run Hstock anymore so i would go with what i have, poteza re-01, treadware of 140, the lowest u can get for sts, and they cost half as much as racing slicks and last 4 times longer. as far as tire pressure thats an odd one. i run mine at 36 in the front cause after the first lap its up to 41, higher than that and im not using the full tread, lower than 36-37 i can feel them rolling over them self. in the back i keep it at 40, they dont do much since our car is so front heavy.with my older 18" rims and all season tires with a treadwear of 420 they have so much stiffness, from lack of sidewall, that its impossible to make them unpredictable and they held a constant .92G in a 50ft radius circle, the potezas however only held a .90g in the same circle, but when it came to track time, i can do a salom(sp) so hard that i break 1.10g every single turn. i would have fun by going to a open wide back road and puting it into 3rd and setting the cruise to 60mph and just slam left and right as hard as want and scare the crap out of my brother who goes racing with me.jump in the seat with someone who does good at a race and you will quickly see how much tires mean, and how they are always pushing you in some direction at all times
Mavrik
Posts: 8072
Joined: Sat Jan 03, 2004 6:41 am

Re: (manicdan)

Post by Mavrik »

Well with most mods, your no longer in stock class. I was running STS.
2007 stage 2 Satin White Pearl Subaru STi 2008 stage 2 Subaru STi hatch See my car at: Mavrik's car page
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