jt1 Posted April 28, 2003 Share Posted April 28, 2003 Went to a track event at CMP this weekend with the porsche guys. Had a great time, but need some advice. I was running in the advanced group, and myself and two fox mustangs were the fastest cars in the group. The two mustangs drivers were friends and had very similiar cars, both with 13" Baer brakes, Griggs susp, one a stroked 302, the other a 351W. Both were running Kuhmo Victoracers, one 245's, the other 255's. Both weighed about 3100#'s track weight. We tried to line up together and ran together a lot. We were pretty equal, but they would pull me a consistent 2-3 car lenghts every lap. On the straights, I could gain a little, and I could outbrake them. We seemed to be about equal in the corners, but exiting the corners they could get on the power much quicker and harder than I could. This was where they were making a lot of time on me. My car is 2700#'s on the track, 49.5%F/50.5%R, 250F/275R coilovers, Tokico 5-ways run in the middle setting, 7/8 front bar, no rear bar, 225/60-15 Yokohama AVSi's, 12.2 Wilwood's. The car typically has a light entry push and is loose off depending on how much throttle is used. Can anyone offer any tips on suspension or driving to get off the corner better? I was trying to late turn-in late apex to get a better run out of the corners, but still getting pulled pretty badly. Horsepower isn't an issue, I can light the tires up easily with too much throttle. I know the car could use a better driver, but I want to stick with the current one......... Thanks, John Quote Link to comment Share on other sites More sharing options...
Mikelly Posted April 28, 2003 Share Posted April 28, 2003 What are your caster, camber and toe settings, also tire presures... BTW, Those tires are problem number 1. Good street tire, but poor choice for a track event. Have you ever had the car setup with corner weights??? We might need to put you on the list to get a set of rear control arms once I sort out the supplier issues... OOOPS, I let that one slip out... Mike Quote Link to comment Share on other sites More sharing options...
jt1 Posted April 28, 2003 Author Share Posted April 28, 2003 Car w/fat driver, 1/2 tank gas LF 706 50.38% RF 654 52.35% 47.65% LR 707 49.62% RR 632 Total 2699 # LF-RR 49.57% RF-LR 50.34% Sorry to misstate the F/R % in the first post. Brain fade. Front toe: 1/8" out Front camber 1 1/4 deg neg, all I can get with my camber plates. Front caster: unknown, no adjustment provisions anyway. Rear toe: Very close to zero, possibly 1/32 in, no adjustments. Rear camber: 1/4 deg neg, no adjustments Starting cold tire pressure 33 psi, goes to 40-41 psi hot. No tire temp data, rears usually gain about 1 psi more than fronts. John Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 28, 2003 Share Posted April 28, 2003 John, Glad to hear the car ran well. Did you get the stick in the car? If you get some track tires you will not believe the difference. Your car will be a different ride on track rubber. I'll be at the track day on May 16. You comming? Mark Quote Link to comment Share on other sites More sharing options...
jt1 Posted April 28, 2003 Author Share Posted April 28, 2003 Mark, I got the tremec in and love it. I had heard of a few problems with shift quality, but I was pleasantly suprised, it shifts great and isn't even broken in good yet. It made a huge difference in the car, it accelerates out of the corners better and I can brake a lot harder into the turns. Less rotating mass I suppose, the 700R4 convertor weighed 45 #'s, my clutch & flywheel only 29 #. I was a little rusty downshifting but got back into it pretty easily. The #$%@&* brand new hydraulic throwout bearing started leaking on the next to last run Sunday, so I didn't make the last run. Now I get to pull the trans again to fix that. I'm planning to come May 16th, I'll see you there. Got the Panasports and Hoosiers on yet? John Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 28, 2003 Share Posted April 28, 2003 John, Panasports are not here yet so I'm still on the 15's. Look forward to running with you on the 16th. Mark Quote Link to comment Share on other sites More sharing options...
johnc Posted April 28, 2003 Share Posted April 28, 2003 Using what you have, try softening the rear Tokico's to 2, adjust front toe out to 3/16", and trail brake a lot to get the car to rotate early. You need better tires (as staated above) and you need lots more camber. You're stuck with a situation where the rear tires have to get back to vertical (from positive camber) before you can get power down. Quote Link to comment Share on other sites More sharing options...
jt1 Posted April 28, 2003 Author Share Posted April 28, 2003 johnc: Thanks for the input, I was hoping you would take a look at it. I'm definitely getting hammered from the apex to trackout. At the last event before this one, I ran with a friend with a stock Z06 quite a bit with almost the same results, except I was not able to outbrake the Z06. What you are saying makes sense, once the car gets out of roll I can put the power down pretty good. Would adding a rear bar and going to a larger front bar, trying to maintain overall balance, help out? I have several F & R bars on hand from previous projects, part swapping, etc. I've been busy with the auto to manual swap and haven't had time to try them. The Yoko's only have a couple of track days left on them. I'm going to step up some in tire for my next set, probably some Kuhmo's. Thanks, John Quote Link to comment Share on other sites More sharing options...
johnc Posted April 28, 2003 Share Posted April 28, 2003 Camber, camber, camber, camber. Did I say camber? Fiddling with anti-roll bars may make you feel better and you might see a little improvement with a bigger front bar. But, you're still only using 1/2 of your tires (the outside half) to accelerate out of the corner. BTW, do you have some kind of limited slip? EDIT: Just say the Quaife in your sig. Quaife's like a soft rear suspension so adding a rear anti-roll bar might exacerbate your current situation. Quote Link to comment Share on other sites More sharing options...
katman Posted April 29, 2003 Share Posted April 29, 2003 Yeah, what JohnC said- camber. I also vote lower rear spring rate and you could add 1/32-1/16 total toe in in the rear (personally I like zero toe for zero drag but you might try it). In the driving technique dept. you can slow down more at corner entry, turn in sharper, take an even later apex. This allows you to unwind sooner as you add power and effectively makes the straightaway you're entering even longer. With a V8 Z you don't get to nail it immediately after turn in like we do in an ITS car, so not being able to get the power down might eventually end up being a case of too much power for the available tires. Something I pray for every day..... Quote Link to comment Share on other sites More sharing options...
David Spillman Posted April 30, 2003 Share Posted April 30, 2003 John, Tires,Tires,Tires..bite the bullet use those Toyo-allseasons for terrorizing the street. More Neg.camber may hurt your straight line drags on the street,cause that car don't sqaut as bad as a lot of IRS Zs due to those spring rates....but guess that limits weight transfer as well....lighter springs may be the ticket. still need a compromise for street driving concerning camber,unless you feel like setting up for the track each time to 2.5-3degrees Try get car close to "neutral"or right as possible before investing in $$tires...may be easier to setup at lower limits of existing rubber Goodyear GSCS or Hoosiers keepem off the street..."especially in the rain" they'll last a while,rotate around,and inside out....track time deserves good tires for Max enjoyment with that said,I've showed up at track more times then not with suspension all screwed up writedown/save anything Katman says.....K knows Zs ...I'm still a rookie Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 30, 2003 Share Posted April 30, 2003 Spillman LIVES. Good to hear from you. Come to a track day and bring the IT car. Quote Link to comment Share on other sites More sharing options...
David Spillman Posted April 30, 2003 Share Posted April 30, 2003 Hey Mark, really want to get a peek at your car with all its new goodies....I'm chasing Kids on dirt bikes for last year now,not as much free time to hang out at the track. that car of your's really hooks up and scoots from what I hear. I'd like to do a test/tune day one Friday soon at CMP if scheduling works out. Source for friday test dates or is track open every friday before club events? david Quote Link to comment Share on other sites More sharing options...
jt1 Posted April 30, 2003 Author Share Posted April 30, 2003 Mark's car is SHARP! and fast, too. There are rumors of it spending about a month at one of the LT1 tuner shops in Charlotte, but Mark won't confirm them. Regardless, it's a very nice car. David, the Friday track days are done by Turn One Motorsports. http://www.turnonemotorsports.com/ Mark & I are planning on going to the May 16th date, load your car up and come on. NO SNIFFING BUG SPRAY AT THE TRACK! johnc & katman: Thanks for your input. What methods would you recommend for increasing rear camber? Offset LCA bushings and camber plates or slots for the strut towers? Both? About how much camber would be a good starting point? I'm going to step up in tires, probably to kuhmos, don't know if my limited driving ability is ready for full slicks yet. Thanks for all the help. John Quote Link to comment Share on other sites More sharing options...
johnc Posted April 30, 2003 Share Posted April 30, 2003 Camber plates and offset LCA bushings. If its a dual purpose street/track car then run poly offset LCA bushings. If its a track car, run Aluminum/Delrin. Start with 2.5 degrees negative for the track and use the offset LCA bushings to get about 1/16" toe-in (adjust the front LCA bushings to get the toe). Be sure to string the car after putting in the LCA bushings to be sure it tracks straight. Quote Link to comment Share on other sites More sharing options...
Mudge Posted April 30, 2003 Share Posted April 30, 2003 Dont know what your front toe is, but some people go 1/16" toe out on front to help turn-in, sometimes even more, thats where the tuning aspect comes in. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.