help with wedge
Moderator: Team
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mickeyspeed
help with wedge
hi hope someone can help us out we are running a gm metric frame monte carlo factory stock on a 1/3 mile asphalt oval have to run same length springs with no spacer of any kind at this point we have 49% wedge in the car but looking to gain more does any one have ideas
I would suppose if they don't allow spacers, spring rubbers or air bags would be out too.
You could comb the junk yards and look for a spring with a larger size spring wire, then cut it to length. You would have to check them with a spring rate checker to see what you have.
If that is not allowed you can preload chassis by making a longer down tube to the corner you want to increase the weight. I have seen these tubes mounted with sandwich blocks and they have several thickness spacers to tweak the wedge. don't skimp on bolts here at least 4- 1/2 inch grade 8 bolts.
A lot of times tire size can improve your cornering (stagger).
There is always preloading front sway bar also. a longer or shorter link on one side will preload a wheel. There are some ideas to think about.
You could comb the junk yards and look for a spring with a larger size spring wire, then cut it to length. You would have to check them with a spring rate checker to see what you have.
If that is not allowed you can preload chassis by making a longer down tube to the corner you want to increase the weight. I have seen these tubes mounted with sandwich blocks and they have several thickness spacers to tweak the wedge. don't skimp on bolts here at least 4- 1/2 inch grade 8 bolts.
A lot of times tire size can improve your cornering (stagger).
There is always preloading front sway bar also. a longer or shorter link on one side will preload a wheel. There are some ideas to think about.
Older I get the less I know for sure
Are you trying to tighten up the car on entry and exit or are you looking for forward bite? There are options depending on what you're trying to accomplish....Bubstr covered many of the options....along with tire size you can play with pressure ...that will artificially but effectively change tire size.....depending on how sharp you're tech guys are you can use an AC option spring in the RF and a 6 cyl spring in the left front...also possibly a station wagon rear spring in the LR....also some models used a rubber insulator/spacer on top of the frt.springs....you would probably want to glue (gorilla snot) it to the upper spring seat (RF only).....also using a new spring in the RF/LR and used springs in the LF/RR may help...if the rules don't prohibit it, the use of steert stock spring spacers (a form of Wt. jack device) or spring rubbers installed in the RF/LR will also help....use the biggest sway bar you can find that will fit and then preload as Bubstr suggested....also these cars respond VERY well to a good set of shocks...I.E., Bilstein AK series, or PRO or AFCO.....good luck
PF
PF
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trikesrule
Yes Trikes it should be a coil car with short stock type 4 link in the rear.
The rules are interpreted differently for almost every track. Usually what they want is the elimination of screw adjusters and after market springs. But you know racers, Enginuity is the mother of invention and there is always more than one way to skin a cat.
It would help a lot if you said what your trying to cure. Just remember a few basics 1 address the problems as they happen, what happens going into corner has something to do with how it transitions and how it leaves the corner. There are sometimes multiple fixes for a car being loose or tight going into a corner but how it transitions and exits will tell you if you picked the right one. 2 the car will always tell you what it needs, Stance feel and tire temps are your link to understanding. 3 A driver has to be flexable. Be able to change driving style to accomadate an unchangable race car. This will get you threw a foul handling race car and later give you tools to push the driver with different chassis set ups and gear ratios for different tracks.
The rules are interpreted differently for almost every track. Usually what they want is the elimination of screw adjusters and after market springs. But you know racers, Enginuity is the mother of invention and there is always more than one way to skin a cat.
It would help a lot if you said what your trying to cure. Just remember a few basics 1 address the problems as they happen, what happens going into corner has something to do with how it transitions and how it leaves the corner. There are sometimes multiple fixes for a car being loose or tight going into a corner but how it transitions and exits will tell you if you picked the right one. 2 the car will always tell you what it needs, Stance feel and tire temps are your link to understanding. 3 A driver has to be flexable. Be able to change driving style to accomadate an unchangable race car. This will get you threw a foul handling race car and later give you tools to push the driver with different chassis set ups and gear ratios for different tracks.
Older I get the less I know for sure
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mickeyspeed
hi guys first off we thank you all for your time and thoughts yes it is a coil car last year we ran carrea shocks this year new rules no racing shocks so we have bilsteins on now car is bouncing to much and rolling over r/f driver says car goes in ok but loose off we can run rated springs with pigtails on rear here are some # all 4 springs are 12inches tall l/f 700 r/f 800 l/r 175 r/r 175 front swaybar 1 3/4 1/2 inch preload tire temps l/f 154 164 164 r/f 190 196 207 l/r 144 142 143 r/r 186 188 188 camber r/f -6.0 l/f2.50 caster r/f +4.o l/f + 1.75 1/4 inch toe out 1 degree camber gain per 1 inch of travel in r/f weights l/f 1124 r/f 888 l/r 773 r/r 604 56% left 41 % rear 49% cross hope this helps thanks again
I would increase the LR to 200 to help the loose off.
Check the pinion angle, if the top arms are stock, it will be way off.
We shortened the upper arms about one inch and re drilled the holes, then trimmed the ends to make them look untouched.
About 2-3 degrees down worked well on our car.
Removing the left sway bar link and installing threaded rod in its place will give a valuble tuning tool. You can then set the bar to have about 1/4 inch of clearance (just like a modified or late model slapper bar) to allow the throttle to be picked up much earlier.
Good luck
RR
Check the pinion angle, if the top arms are stock, it will be way off.
We shortened the upper arms about one inch and re drilled the holes, then trimmed the ends to make them look untouched.
About 2-3 degrees down worked well on our car.
Removing the left sway bar link and installing threaded rod in its place will give a valuble tuning tool. You can then set the bar to have about 1/4 inch of clearance (just like a modified or late model slapper bar) to allow the throttle to be picked up much earlier.
Good luck
RR
mickeyspeed wrote:hi guys first off we thank you all for your time and thoughts yes it is a coil car last year we ran carrea shocks this year new rules no racing shocks so we have bilsteins on now car is bouncing to much and rolling over r/f driver says car goes in ok but loose off we can run rated springs with pigtails on rear here are some # all 4 springs are 12inches tall l/f 700 r/f 800 l/r 175 r/r 175 front swaybar 1 3/4 1/2 inch preload tire temps l/f 154 164 164 r/f 190 196 207 l/r 144 142 143 r/r 186 188 188 camber r/f -6.0 l/f2.50 caster r/f +4.o l/f + 1.75 1/4 inch toe out 1 degree camber gain per 1 inch of travel in r/f weights l/f 1124 r/f 888 l/r 773 r/r 604 56% left 41 % rear 49% cross hope this helps thanks again
First a disclaimer. It's imposible to tune someones chassis over the Net. We can't see how much of what it is doing or even missing something unsaid. That being said, what we can do is give you the tools to try and cure the common problems.
The first problem seems to be execesive movement in the chassis, diving down on front and rolling over too much. This can be cured, depending on severity, with as little as driving style change (power braking going into corner and trail braking coming off), or increasing rear brake bias. If it is more severe, It would suggest that the spring rates are not high enough or the shock rates are low. Remember once you have a base line, if you increase spring rate in the front, you need to increase it in the rear to maintain a neutral balance car. You will find yourself with spring//shock packages for each track you run. Ideal is to have a spring that is just soft enough to maintain complyance of tire and track. Too hard it bounces tire, too soft it is wasted energy in extra movement. The shocks will add or subtract spring rate and determine the speed the movement takes place. As a general rule, Lean to a softer spring and stiffer shock if needed. It allows front to rear weight transfer better especially on flatter tracks. Other options are stiffer sway bar and lowering roll center, or adding L/F R/R cross weight, as in above post (200 lbs spring in R/R), The down side of the cross weight is it could develop a push in and threw transition and can interfear with overall front to rear weight transfer. There are a few things to think about.
Now for the loose off. I really beleve the main problem here is the roll. If you control the roll you will be able to transfer some more weight to L/R coming off the corner and use it a bit more. There are other tools to cope with loose off. Stagger or lack of it. Tire presures too a point. Rear steer, that wouldn't be easy with your rear suspension.
Older I get the less I know for sure
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trikesrule
Looking for more wedge. Hhhhhmmmm dare I say it. Bend - twist the chassis on a panel beaters rack. This may seem extreme but as you know your corner weights now set the car back to zero then twist the chassis to almost that much on the rack put her back on the scales and see how much more is needed then head to the track and start tuning to establish a baseline again. Some real good ideas above like changing the arm angles. I know that worked for this teams car(s) that I set up. U can turn that roll into roll steer if u play around with arm angles. I use differing shocks to control transiants in roll. I spoke to a cam grinder (and a great dyno man) and changed the way the engine comes on out of the corner. At last seasons end I altered the compression (and a couple of other things) also - went looking for driving torque off the corner. Found a heap! I never changed the diff ratio but it was on the cards. Just found a final drive ratio that worked the tyres well by playing around with tyre sizes. I actually went taller and wider on both rears but more so on the LR. I was looking to make the car be on the verge of having a little push on exit so the driver could get on it sooner/harder than the other vultures. This effectively made the straights longer. When u set the car to be like this the driver must be tidier coming into the corner. If he gets loose by being to agressive coming in or is one of those that likes to stomp the throttle on and off thru the corner he can actually make the car too loose. Driver / Set-Up guy communication is real important. Get together straight after each race. Cool unemotional heads solve handling problems real quick. Keep playing you will find a way..........trikes
Last edited by trikesrule on Fri May 25, 2007 3:14 pm, edited 1 time in total.
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trikesrule
Ok Just been studying your tire temps. From what view are we reading those? Sittingin the car or standing in front? Camber gain is ok but how are you setting your toe-out? I set ours with the right side wheels straight ahead then put the toe out into the LF. I only run 1/8" on dirt! With more wedge less toe out is needed to turn in hence less straightline drag = faster car down the straights. 56% left may be a little too much. Try a little less. Can u adjust R/C in the rear? If so raise it 1/2". I'm not a fan of sway / anti roll bars in racing. My line of thinking is if I can't get the car to handle disconnect the sway bar and start over. Most times I get to remove them entirely on dirt and circuit. This is one of the cars I set up. She's a bit beat up (full contact class) But the number on the roof has been there for two years now. Time for a reshell now the season is over for us........trikes
I'm not into Sway bars in the front of Dirt cars either. They have to have suspension movement up and down to maintain complyance with a rough track. The sway bar can inhibit this movement. But on a paved track where your chassis or rules limit placing front roll center where you want they can be a good thing. The bumps and ruts just aren't there.
Older I get the less I know for sure