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Old 02-15-2003, 07:11 PM   #1
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Default Tweaking a touring car?

I was wondering what everyone was doing or using to tweak there cars. I normally use a tweak station but I dont think it has been quite accurate so I am looking for ideas.
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Old 02-15-2003, 07:56 PM   #2
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MIP or integy tweak station is the best way really. If you are having a hard time getting your car to balance out on the tweak station then there is something wrong in your suspension or chassis, or both. Your shocks might be different lengths left to right, or your chassis can get twisted. Check all those things out. Tweak stations are the way to go.
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Old 02-15-2003, 09:07 PM   #3
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I normally use a tweak station. But sometimes I get big variations in tweak. I guess what I am saying is that I thought about using the hobby knife in the center of the car to adjust tweak but I am looking for a more consistent way of adjusting tweak. 1st: question: when you put the front wheels on the pivoting block do you adjust the back shocks or the fronts shocks. 3rd: Do you also put the back of the car on the pivoting block and then adjust tweak also or do you just do the front?
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Old 02-15-2003, 09:27 PM   #4
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MIP station

If the bubble is to the right, there is too much weight on the left tire; Therefore, either add more preload to the left rear shock or take some out the right rear. flip the car around and do the same with the rear
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Old 02-15-2003, 10:05 PM   #5
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On the MIP station you adjust the preload of hte side that's on the pivoting block. Also, make sure your non-pivoting block is flat by taking the pivoting one w/ the bubble and placing it on top of it. Adjust that until it is level. Always make sure your block is level before you adjust tweak, otherwise you'll never get good/consistent results. Also, place the bubble block at an diagonal on the stationary block and the beam. Make sure the stationary block and the beam are at the same height (bubble is in middle). Then center your car on both blocks. If the rear end of the car is on the pivoting block, adjust the rear shocks and visa versa. The hobby knife trick works, but you have to do it perfectly in order for it to work. The hobby knife thing works much better for 12th scales because of their weight.
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Old 02-16-2003, 05:21 AM   #6
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I always adjusted the side on the pivoting block and check to make sure the whole tweak station is level every time I usa it even if it is in the same spot. Some people at the track tell me I am doing it backwards but some people think I am adjusting the car correctly.
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Old 02-16-2003, 10:49 AM   #7
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Default Tweaking a touring car?

Guys;

Here is a variation on setting tweek thast I learned from an old time racer.
Always start with the rear, but put a block under the chassis in the front to eliminate any influence of the front suspension. Adjust the rear, THEN remove the block and turn the car around and set the front and then recheck the rear one more time. A ride height gauge can be used for the block. Something flat and true that will raise the front tires off the ground when you do the first check of the back suspension. The block is not used after that for the remaining checks.
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Old 02-16-2003, 03:23 PM   #8
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Pops, it seems to me that using that method would only be used for setting droop or am i missing something?

I used to use my tweak station to set droop but when i was done the car would pull left on the track. I bought a set of dynamite setup gauges and found out that the TC3 chassis twist was affecting droop in a bad way. Used the dynamite gauges to set droop, put it on the tweak station, back to the track, perfect tweak!
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Old 02-16-2003, 06:20 PM   #9
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You are missing something indeed!

Droop is something totally different. A "Tweak" station is NOT used for setting droop. Putting your car on the Tweak station should be the last thing to do during set-up. All other chassis adjustments should be set first, then check tweek. If there is a major problem that can't be easily corrected with the shock preload adjustment, something is out of whack and needs to be corrected first.
The reason for putting a block under the front of the chassis when checking Tweak, (I said this already before) is to eliminate any influence the front suspension might have on the rear. Once the Rear of the car is set, there is no need to use the block again. The Reason for setting the rear first, is the rear is more critical to the handling of the car.
As for Droop "Blocks", there is really no reason to use them on a Touring Car chassis. Simply, just use the ride height gauge to set ride height, then push it under the chassis further until the tires just lift off the board (set-up, table, glass, etc.). The difference between ride height and this measurement will be your Droop.
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Old 02-16-2003, 06:25 PM   #10
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Default Hobby Knife Method

Hey Guys !

I've usually use someone elses tweak station at the track because I don't have one , what is the method for using a hobby knife to do it ?

Thanks alot.

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Old 02-16-2003, 07:14 PM   #11
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Here is what they tell you about using a hobby knife to set tweak " after all your chassis adjustments, find the center of the front and rear of the chassis and mark it somehow. Then set the car down on a flat level surface, but make sure you can see your marks on the chassis to find the center. Take your hobby knife blade and run it under the rear or front of the car where your center of your chassis marks are at and then tilt your hobby knife up slowly until the tires come up off the ground. When looking level with the table you happen to see one tire lift off the ground before the other then your car has tweak. While looking at your car (with the front end towards you as an example), if your right tire (which is actually your drivers side) comes up off the table first then you would need to put more pressure on the left back shock (which actually would be the passenger side) or take pressure off the back right (which actually is the drivers side of the car). Then flip the car aroud and do the same adjustment for the rear of the car.
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Old 02-16-2003, 09:18 PM   #12
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that is the method i use to set my tweak now because if your droop is off this will correct for it.
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Old 02-17-2003, 07:33 AM   #13
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hey guys. tweak, and droop are, of course, two different things. running with a tweak means that there are not even forces l/r on the tires. just because you're tires don't come off the surface at same time doesnt mean your car is tweaked. that could be a downtravel problem, also known as droop. if a chassis has a tweak, that could mean that the bottom surface is not flat front to rear or side to side. yes, there are many reasons that a car will be tweaked, but assuming you start with your shocks evenly spaced, it's likely in the chassis.

what i first do is find r/h on a flat board. i check at four points. basically chassis height before/after each wheel. if my chassis is tweaked, there is no way all four corners of the chassis will have the same ground clearence. what i want is a balance. the left and right of each end should average to the desired ride height. others level an end and let the other end finish up wherever, taking an average at that end. with that method, you would not use the flat end to adjust for tweak, it is done on the twisted end. i use both because i want my chassis to be nearly level at both ends.

once you've set r/h and tweak, you can set droop. i think the best way here is the center of the shock tower method. by lifting one end, you can see exactly what your droop is. the end on the ground will hold the car at the same level that it will run at. some set the car up on a block or on something that goes across that end of the car. if the chassis is dead flat at static r/h, it works, otherwise, it doesn't. if you set your droop assuming that that end of the car sits level...and it doesn't, your droop will not be symetrical on the track. in the centerline your droop will not be affected, but when you pick your car up by the towers, you'll see the imbalance. that is a droop problem, not a tweak.

setting tweak and droop is very inticate because one depends on the other. on foam tires, that wear down from the beginning of the day to the end, you've got to remember to give more droop as the arms are lowered to push the smaller diameter tires back to the original r/h. i've seen dudes forget over the course of a weekend and watch the car become twitchy blaming it on a lack of sidewall left on the foams, when it was likely a combination of both that and the fact that the droop went to nothing as the collars moved down the shock.

just my .02.
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Old 02-17-2003, 10:42 AM   #14
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Default seaball;

Droop should NOT be used to adjust tweek. Every single chassis adjustment must be equal side to side for the car to handle properly.
Placing a car on the Tweek Station should be the last step in one's set-up proceedure. Then very minor adjustments to SHOCK preload is used to correct any MINOR tweek variations. If you need to make the shock collars more than 1 turn different from side to side, there is a problem.
I set my shock lengths to be +/- .0005" at the same end of the car. For this reason I NEVER use O-rings as internal spacers.

The Knife method is too inaccurate. Slightly more weight on one side of the chassis will cause a false reading. This is why they sell 4 scale boards for this, though not really needed for Touring Cars.

For you Guys that understand chassis set-up. Try putting a block under the Front of the chassis when checking tweek on the rear. This really gives a better overall indication of Rear tweek.
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Old 02-17-2003, 02:07 PM   #15
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hey pops,
i definately agree that droop should not be used to account for tweak. that is why lifting a car at the center to check droop can be used if, and only if, your tweak is already in check. hence, i believe that droop should follow tweak settings.

the problem i have with setting tweak last is that it changes your droop if you need to adjust at all. say you're leaving tweak for last in your setup. everything else is ready to go. you're running droop of 1mm front and 3mm rear, not uncommon for a carpet setup. you're finishing off with the tweak board and your chassis is 1mm twisted measured at the wheels from front to rear. no problem, 1/4 turn of the collar on front right, and -1/4 on the left and voila. you're set. only that wheel that you just preloaded an extra 1/4 turn just lost 1mm of droop and the other side gained 1mm. that's why i always recheck droop after i know the preload collars are not gonna move.

i use the knife method to set droop, but pops is right. if you have weight imbalance, that imbalance will shift to the planted end and cause the car to torque along it's centerline or thereabouts when lifted. however, i still use it as i never hit the track with a car that's more than a few grams different l/r. i dunno too many people who do.

and the block method is surely a way to check for tweak at the other end. the method by which racers use a block or rod for droop that i was describing is one in which that block or rod is used at the same end that your working on for droop. i've seen dudes setting droop by lifting that end of the car up a desired amout above r/h and adjusting so that the tires just barely contact the ground left and right. which is great if your chassis is flat across that end. mine usually aren't. the molded cars are awesome for not tweaking out. cars with top plates, however, can be a nuisance. the top plate should be relieved every race and tweak rechecked. some of my cars just want to run with a slight tweak down the chassis. i just set everything up around that. if i don't, tapping the boards just prompts the chassis to find it's happy point anyway.

well, that's just one opinion of race day setups. that's why we have this forum. tons of ideas and we all get to do it the way we think is the most practical. later.
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Last edited by seaball; 02-17-2003 at 02:09 PM.
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