Suspension and Chassis Questions about your suspension? Need chassis advice?

bad launches due to traction

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Old Aug 5, 2004 | 08:39 PM
  #1  
spekbikes's Avatar
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From: london ontario
Car: 87 iroc
Engine: mild 350
Transmission: 350 turbo
bad launches due to traction

got no traction, i lost to a lincoln kuse all i did was spin first and most of second!! i also have the big 7/8 inch rear sway bar with jsut rubber bushings.

i got no money, but got a nice lathe, mill, welder, so i can make jsutabout anything!
i made lower control brackets and they didnt help my traction! i have nowheel hop, my tires jsut spin.... is there any point in working on my suspension if my tires cant handle it?

i have a few sets, a bf good rich tire, kelly tire, comp t/a's(new) , i have tried all, and i cant manage to hook up!

should i make lower control arms, and a torque arm on a 3 degree angle! or is that again jsut going to make it worse until i get a set of slicks?
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Old Aug 5, 2004 | 10:07 PM
  #2  
IHI's Avatar
IHI
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From: Waterloo, Iowa
Car: 86 firebird with 98 firebird interi
Engine: pump gas 427sbc Dart Lil M 13.5:1
Transmission: Oldani TH400 w/ BTE 9" convertor
Axle/Gears: 31 spline Moser/full spool/4.11Rich
slicks first!!!!! Should be a manditory thing for anybody wanting to know what their car is really gonna do. But usually not budgeted in since most cars only see the track maybe twice a year if that.
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Old Aug 5, 2004 | 10:18 PM
  #3  
Wezzeles's Avatar
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From: Princeton, NJ
Car: Camaro
Engine: L03
yo IHI

thats probably the most true thing ive ever heard. someone should sticky this or put it on the news page
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Old Aug 6, 2004 | 06:57 AM
  #4  
SweetS10v8's Avatar
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From: Lima, OH
Car: '89 Formula 350 & '86 Z28
Engine: L98 & 355ci
Transmission: 700r4 in both
Well you see the problem, "Tires are spinning". The next logical step would be not to press the gas that hard. Anyone can spin the tires like mad, its just a waist.

Learn how you have to drive your specific car for maximum results. Your engine seems fairly stock, going off your sig, so traction is possible.
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Old Aug 6, 2004 | 01:24 PM
  #5  
spekbikes's Avatar
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Joined: May 2004
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From: london ontario
Car: 87 iroc
Engine: mild 350
Transmission: 350 turbo
i know, its not wild at all.gears.cam.intake... all of about 300 hp, haha, but its tuff, kuse when it goes green i jsut think pushinghte pedal farther is guna go that much faster! and then im spinning. i either spin or i dont get on the gas enough! either way i always get a bad launch



so basically, i shoudlnt do any more suspension until i get the slicks! then worryafter that then eh?
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Old Aug 6, 2004 | 01:36 PM
  #6  
IHI's Avatar
IHI
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From: Waterloo, Iowa
Car: 86 firebird with 98 firebird interi
Engine: pump gas 427sbc Dart Lil M 13.5:1
Transmission: Oldani TH400 w/ BTE 9" convertor
Axle/Gears: 31 spline Moser/full spool/4.11Rich
Mu suspension is stock and you can see what that'll do Heck my struts have over 120K on them as well as the front springs, rear springs are the same story, but shocks are stock replacement gabriels I got cheap at the parts store.

When I had the stock 305 I was hooking up on 235/60-15 mastercraft radial tires at 18psi and getting 1.95 60's running 14.6-14.8 depending on the air that day. But since then the cars always had stickies, when I switched the relocation brackets from Spohn I noticed zero improvement in anything, as well as putting on the tubular control arms again, zero gains anywhere as far as numbers. This new 9" has the LCA in the factory position and I did install air bags since the car is launching pretty hard now and has a tendency to roll the body over, so the air bags help keep the rear of the car planted.

For straight line performance the factory stuff is pretty good, but if you dont have the right kind of tire, your bringing a knife to a gun fight so to speak. Will guarantee your traction problems are gone once the sticky meats are installed!!!! Last year with the medium motor I was getting 1.72-1.74 60's on ALL factory suspension. The newer parts will help tighten the car up and help make it more consistent since there is less places for flex to occur, but for better traction get tires first...quick, easy and cheap. That way when you start adding more performance parts and fine tuning you'll have concrete numbers to compare too instead of "well I kinda spun this pass, so maybe the timing adjustment was worth some added power" You need "for sure" numbers to compare future mods to and if your spinning you'll never get it.
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Old Aug 22, 2007 | 12:55 AM
  #7  
kowboy59's Avatar
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From: kissimmee fl
Car: 88 iroc-z z-28
Engine: 383
Transmission: th400
Axle/Gears: 3.42
Re: bad launches due to traction

I have a quicky question. If i go out for the night to the races, what should my rear tire pressure be to get good grip. right now i have 235 60 but i will be getting a set of 255 within the month. also when i build my 383, i will have around 500 horses. Is there any other stuff i should do to my suspension besides subframe connectors. its just gonna be a daily driver/strip car
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Old Aug 22, 2007 | 11:57 AM
  #8  
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From: Michigan
Car: 1986 Chevy Iroc-Z28
Engine: 1989 TPI 350
Transmission: 700R4
Axle/Gears: stock 10 bolt with 2.73 gears
Re: bad launches due to traction

Put some extra weight in the trunk. I put about 150 ibs in my trunk and I really noticed a differnce with rear traction. Because the car is rear wheel drive it has harldy any weight sitting back there. It doesn't matter if you put street legal slicks on it. No weight no traction.
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Old Aug 23, 2007 | 02:23 PM
  #9  
antman89iroc's Avatar
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Joined: Jun 2005
Posts: 1,440
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From: huntsville, al
Car: 89 IROC
Engine: 6.8 HSR N2O
Transmission: TKO 600
Axle/Gears: 9" Moser 3.50 True trac
Re: bad launches due to traction

I put a lot of faith in sub frame connectors, LCARB, and boxed lowers. Also, as far as regular tires go, I've noticed an advantage with all season tires vs summer tires. It has a lot to do with the road surface too. My car turns 1.9x 60 foot times with the above mods an Pirelli M&S tires and a stock stall. Just leave as hard as you can WITHOUT spinning the tires. Sometimes you gotta modulate the pedal rather than just "puttin the metal to the pedal -and the thing on the floor!"
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Old Aug 27, 2007 | 02:39 PM
  #10  
Shagwell's Avatar
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From: Southwest Florida
Car: projects.......
Re: bad launches due to traction

Originally Posted by jake150129
Put some extra weight in the trunk. I put about 150 ibs in my trunk and I really noticed a differnce with rear traction. Because the car is rear wheel drive it has harldy any weight sitting back there. It doesn't matter if you put street legal slicks on it. No weight no traction.
Although this does hold true to some extent, I won't go into all that is wrong with your thinking. Weight on the rear tires is varied more by suspension geometry than any amount of weight you feel like dropping in the trunk to make the car heavier and slow it down more(every extra 100lbs is +.10 to your e.t.) My car gets 1.66 short times on 17" wheels and tires. All in a 4001lb car with a manual transmission.

Worn out/cheap stuff doesn't control the motion of the suspension, thus cannot control traction. Check all bushings. Check/replace the rea shocks. These cars are at minimum 15 years old, some parts have been worn out for years now. Next thing I would change would be the gears. Many of these cars came with 2.73 gears. Contrary to popular belief, shorter(numerically higher) gears tend to be easier to hook. Street tires are all about controlled spin. The steeper the gear, the faster the wheel speed wants to increase thus the harder it is to control the tire speed/spin. As for air pressure, take it to a track and experiment. Every car and every tires is different. Try to go on a runday sunday type event where you car run all day. Experiment with different launch rpm, different go-pedal apply rates, etc.
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