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Discussion Starter #1
For those of you who autox some. I have done 2 of them and won my division both times. But I tend to understreer on tight corners. I still have the stock front tire size and in the rear I have 265-40-17..I also have the TRD sway bars front and rear. My question is if I go to 245-45-17 in front or upo 1 size like my rears will this help my understeering problem? Also do any of you use your emergency brake for really tight corners?

Jeff
 

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If you're just starting out, I can just about guarantee that a big part of your understeer is driving technique rather than the car. Almost everybody tries to carry too much speed into corners, brakes too late, and ends up with a lot of understeer at first. If you're not able to hit the apex of the corner, or are unable to accelerate before you get to the apex, you're going in too fast. If you're a part of the 2% that doesn't enter corners too quickly at first :), then the first thing I'd do is make sure you have adequate camber up front. You'll need at least -1.5 degrees, to keep the tire flat on the ground while cornering. Don't make any other suspension changes until you get your alignment right and get good tire temperaures.
 

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Discussion Starter #4
Andi,
SO if I put the stock front one on and keep the TRD rear that will help me oversteer some? What about tire size? I have stock size up front and have 265-40-17 on rear. I wanted 275 but Toyo didnt make that size in their T1S tires:( . I also still have the alignment that came with the car when I got it new in 98:D Would the car handle better for road racing with the stock front and TRD rear as well?
Jeff
 

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463supra said:
Andi,
SO if I put the stock front one on and keep the TRD rear that will help me oversteer some? What about tire size? I have stock size up front and have 265-40-17 on rear. I wanted 275 but Toyo didnt make that size in their T1S tires:( . I also still have the alignment that came with the car when I got it new in 98:D Would the car handle better for road racing with the stock front and TRD rear as well?
Jeff
Yes, the stock front / TRD rear combo will give you a little bit mor oversteer. As will more negative front camber as Eric mentioned.

As for road racing.. depends on your driving style. I have a stiffer rear swaybar than front and I like it.. but I like oversteer.. :)

Andi
 

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Discussion Starter #6
I will try putting the stock one back on and see how that goes. I also like some oversteer. I dont like much body roll either.
Jeff
 

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Are you autox/solo 2 under SCCA rules? If you are your rear TRD bar is illegal if you are running under a stock class. For a Supra that is Super Stock. Don't let anybody peek under the rear of your car if you are in Super Stock and don't tell! If you are running in a prepared class, I think it is B Street Prepared, then I would be surprised you aren't gettig your butt kicked (not to say you aren't a good driver) but there are a boat load of mods cars can do in that class that would make most cars wickedly fast (including bigger rims and diff. springs etc). I guess my other question is aren't people showing up with DOT race rubber like Hoosiers or Kuhmos? Running against other cars with tires that are sticky enough to pick up a paper cup are tough to beat.But hey that is not your question.
I would definitely go to at least 245s up front. That will help with the understeer. For some reason Tire Rack doesn't recommend anything bigger on the front rims but I see at least for autox people are stuffing bigger tires on the rims. (Wonder how safe that is for the street). As to whether going to a 275 wil help the balance between grip front and rear, I believe it would based on my experience. I am getting ready to go the DOT race rubber on another set of rims route but currently I am running my street tires. I still get significant loss of traction in the rear including power on (but controlled) oversteer. I don't want to lose the ability to overotate my car in tight turns with throttle lift/turn technique. I think with 275s you will get a higher potentia lateral g but still be able to overotate when you want and be able to accelerate harder (and still see a little oversteer). Right now my rears are 265s and I wish I had more. But yeah at some point too much rubber at the rear and not enough in the front you wll turn into a plow and that sucks.
My $.02
Barry H. 94ttsupra 6sp. Super Stock
 

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:pat:
Accidently posted before I commented on your question as to alignment. I changed my alignment to the "Lance" recommended alignment figures you can find at www.mkiv.com in the tech article section. They are a compromise set up for the street and track which changes camber and caster up front and toe in the rear. It dials out some of the understeer by putting in more negative camber. So far I like it but am tempted to dial in a little more negative camber up front. The Lance alignment supposedly alleviates the rear tire inside tread excessive wear problem. I know my car had an appetite for the inside rubber on the rear. I haven't had the alignment long enough to verify a difference on rear tire wear. I would try it and see what it does for you and you can change it from there based on your experience.
Barry H. 94tsupra 6sp.
 

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Discussion Starter #9
Yes I run in the street prepared or modified. I cant run super street because of the boost controller. It is considered a engine mod:rolleyes: I use low boost and I do plow quite a bit but part of that problem is me going into the corners too fast. I do fairly well in my class though. there is another race tomrrow but I will not be running in it. I will go watch part of it with my 2 boys though..:D
Jeff
 

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Saw your reply. I don't know about you but my upgrade for Solo 2 is going to be rims and DOT race rubbr. Unfortunately that usually entails a trailer hitch, and trailer too. Yeah coming in too deep is the single most common mistake (among many). I just started back doing Solo 2 after a twenty year hiatus. I got lucky and beat the 2000 Southeast Div. Super Stock driver on my first time out on street tires. But then he was driving a new car, BMW M Coupe and his Hoosiers were going South on him. Hey I will take my wins anyway I can. I beat him once more but last month he spanked me pretty bad but he should becaue he has race rubber. As a note that driver actually went down in tire size to 245s on all fours and believes his car handles better. It may be a question of being able to get the tires up to temp better. Good Luck.
Barry H. 94ttsupra 6sp. Super Stock
 

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Well hell, right after I posted I looked at your location and saw that you are in Chattanooga Tn. I am in Birmingham. I was thinking about coming up to Chattanooga for the Solo 2 this weekend but just got back from a week of vacation and can not. How is the surface where the event is held. Is it a tire eater or fairly easy on tires? I would like come there to run. I just don't want to end up with bald tires after just four runs. Man I would love to check out your car and mods if I come up there.
Barry H. 94ttsupra 6sp.
 

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Discussion Starter #12
bwill I am not going to be able to race in this one:( I will probably come by for a while and watch and talk to some buddys. I would love to meet you. Yes I also am thinking about getting another set of rims..(stock) and putting race rubber on them I believe that would help more than anything. The course is in a big parking lot on lee HWY just off of 153. It is not a smooth course but doesnt seem to eat the tires too badly. I have a red Supra with the tag 460 HP on it. What will you be in if you come up? I will have my 2 boys with me (2 and 6 yrs old) if I do come I want to show them what I like to do...I would love to meet some other supra people because there just arent any around here unless you go to Knoxville.

Jeff
 

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Hey, Jeff,
Wished I was coming up to Chattanooga but after being on vacation for a whole week, I have things to take care of at home. However, I do plan on coming up there sometime to run. I have been to Atlanta which is very competitive. I definitely need the race rubber. Yeah I would love to check out your car. Hope to see you at an event sometime. Haven't seen another Supra turn a wheel in anger yet. Would like to see it.
Barry.:bthumb:
 

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Discussion Starter #14
Barry,
let me know when you will be up this way. You have a 94 what have you done to your dog? Love to see it. I as well have never seen someone else getting on it in a Supra.. Something I do want to see.

Jeff
 

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Jeff,
Right now mine is bone stock. I am going to buy an exhaust in the near future. Next is the race rubber wheels, trailer, hitch. I need to buy that stuff first before I put on a dp, bcc because then I get bumped out of stock class and I will be street prepared at that point. If I read street prep rules right they don't allow a BOV. What the heck? Want to put a HKS one on to help save the turbos. Go figure. Yeah I will try and contact you before coming up to Chattanooga in hopes of hooking up at the event. Until then, see ya.
Barry H. 94ttsupra 6sp.
 
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In Solo 2, the Supra TT is in the E street prepared class if it modified within the constraints of SP. I've seen firsthand how increasing front camber helps the understeer situation. I went from -1 to -1.75. I'm running BFG R1s (better road race tire than autox) on stock rims with 255 front and 275 rear. They seem to work decently on the rims. I understand the Kumho Victoracers or Hoosiers are better for autox because they heat up faster. BTW, I'm currently on Konis/Eibachs with TRD rear bar only, and still have more body roll than I'd like. I've only run 2 events and still tend to overcook the entries, a common rookie mistake. Jeff in Colorado
 

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Hey Jeff in Colorado,
Good to hear from another Supra running Solo 2. I could not remember what street prepared class the Supra gets bumped into. I am getting the rule book so I can read the "fine print" on just what is allowed. How do you like the 255 fr/275 r set up? Does it have good stick on DOT race rubber but still allow the manuvers like sudden throttle lift induced oversteer to overotate the really tight slow stuff? Locally we also hold Solo 2 events on a road racing track which is a total blast. So you really get to set up a long four wheel drift through the sweeper and roll into the throttle on the exits. They just put a 5 cones slalom or gated slalom in the middle of the straight to keep you from busting the 80mph mark. I say this to ask you are you comfortable with the 25 on the front. Tire Rack doesn't "recommend" anything bigger than 245 but what that is based on, I am not sure.
As to tires from talking to the guys who are contenders for the divisional Super Stock title in my region, the opinions seem to run along the lines that Hoosiers may have a slight edge on times at least intially but that after time, they fall off in performance more than the Kuhmos. The Kuhmos definitely last longer and are significantly less expensive. I think they have the same durometer though. There was an article in last month in Grassroots Motorsports where they did a tire comparision of the Kuhmo Victoracer, the Hoosier, and the Toyo DOT race rubber. The end result was that the Kuhmo ended up slower than the Hoosier by a margin that was next to nothing. The Kuhmos were slower at first and once they get the pressures right, they were great. Would love to hear your thoughts on if you think the 255/275 is about right for stock rims since I am still super stock.
Barry 94ttsupra 6sp.
 
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Barry - I bought these slightly tires used from a road racer so don't know what they were like new. The 255s in front look a little wide for the rim but seem to work fine (only had 2 events on them). I'm confused on classification now - the local Solo 2 listing shows all Supra Turbos as ESP. An SCCA moderator just told me I should run in BSP or SM. One issue is the boost controller, which is not allowed in SP. The issue I made is that the boost controller is actually used (by me) as a limiter once a DP and exhaust are added. The guy I bought the stock wheels and R1s from said that combo worked quite well on the track. I'm guessing I'll go with Kumhos next season, on some Ronal wider rims (9, 10.5) I already have. I'll also be installing the HKS coilovers next week. Too bad we don't live close together, nobody out here is running a Mkiv in Solo2 but me. The overall grip level of the R1s seem good once they get some heat in them. The first run of the day on them is generally a bit slower than later runs. Hope this helps, Jeff
 
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Barry - I was just informed that the Mkiv Turbo goes into BSP. Our local SCCA website made no distinction in the years. I'm going to run in Street Modified since boost controllers aren't allowed in Street Prepared. Jeff B.
 

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Discussion Starter #20
The 2 events I ran in they had me in B Mod class. I think I can run in either street modified or street prepared. It is the boost controller that changes everything. Ours here in town are not held on a road course but rather in a parking lot. The really fast cars all use BFG racing tires or Kumo Victoracers. There is not much competition in my class here. I do it for fun on street rubber. Mine is a daily driver. I want to get a set of wheels to put race rubber on. I would also like to get a set of tien coilovers..someday.. What I plan to do next year is go to one of the track days at Road Atlanta..My mechanic said he would railor me down. He has 2 MKIV wheels now and is looking for 2 more for me..

Jeff
 
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