HiTech Posted September 2, 2007 Report Share Posted September 2, 2007 DO YOU RUN YOUR CAR SHORTER .. ON THE RIGHT.. OR LEFT SIDE .. OR EVENED UP .. Link to comment Share on other sites More sharing options...
racer61 Posted September 3, 2007 Report Share Posted September 3, 2007 normally shorter on right. But it depends on what you trying to accomplish. Loose, tight, stability... Link to comment Share on other sites More sharing options...
HiTech Posted September 3, 2007 Author Report Share Posted September 3, 2007 .... longer alittle and the car gets tight longer the race goes ...even and it starts out loose and then it gets tight starts to push ...shorter just alittle and it is alittle loose at start .but she comes in nicely after 3 to 4 laps ..and stays that way ...never pushes ... so i was wondering how many went short or long and for what reason ...i know those are secrets ...dont have to give out what your running it at ... Link to comment Share on other sites More sharing options...
jakdad Posted December 10, 2007 Report Share Posted December 10, 2007 I believe you're right Oldtimer. We moved our right rear spring forward 1/4" and it worked great. Of course that was back when you had leaf springs in back. We moved it up another 1/4" to try it out. Went through the turns pretty good but smoked the right rear all the way through. We quickly put it back to the 1/4" hole. Not one of my better ideas. Link to comment Share on other sites More sharing options...
HiTech Posted December 10, 2007 Author Report Share Posted December 10, 2007 I believe you're right Oldtimer. We moved our right rear spring forward 1/4" and it worked great. Of course that was back when you had leaf springs in back. We moved it up another 1/4" to try it out. Went through the turns pretty good but smoked the right rear all the way through. We quickly put it back to the 1/4" hole. Not one of my better ideas. .i would like to have seen those tire temps .across ..at a half ....nothing wrong with ideals .you useualy stumble on to something ..wont work if you dont try it . Link to comment Share on other sites More sharing options...
poorboy Posted December 15, 2007 Report Share Posted December 15, 2007 Oldtimer am I reading that correctly? Longer on the right makes your car tight and shorter makes it loose. Link to comment Share on other sites More sharing options...
HiTech Posted December 15, 2007 Author Report Share Posted December 15, 2007 Oldtimer am I reading that correctly? Longer on the right makes your car tight and shorter makes it loose...based off our typ of chassis ..and that is what happens . Link to comment Share on other sites More sharing options...
NickHolt Posted December 15, 2007 Report Share Posted December 15, 2007 It's not the whether a car has a longer wheelbase on the left or right. It's whether there is any rear steer in the car. There are two types of rear steering effects. 1) Cock the rear end. If you pull the left rear forward, you will experience a car that is always steering (to whatever degree you have pulled it forward) to the wall at the rear of the car. This is what you're describing when you say the left side has a shorter wheelbase. This is call rear oversteer. If you pull the right rear forward, you will have just the opposite. 2) Dynamic roll steer. This is when the rear is not pulled forward on either side, but moves forward on one side or the other as the car experiences body roll in the turns. It's like a little man steering in the back of the car, but only when the car rolls due to weight transfer. The angles and lengths of the rear trailing arms determine whether there is roll steer present or not. Obviously, cars that are basically loose do not need any rear oversteer. That would just compound the loose condition. And cars that are basically pushing, do not need any rear understeer. But cars that are basically loose might benefit from a small amount of rear understeer while cars that are basically tight would benefit from a bit of rear oversteer. Just as obviously, the only way you can lengthen or shorten the wheelbase at the front of the car is by changing your caster settings (or remounting your lower a-arm mounts - illegal in most stock classes). So most of the wheelbase changing is done at the rear. Hope this helps clarify this discussion. Nick Link to comment Share on other sites More sharing options...
HiTech Posted December 15, 2007 Author Report Share Posted December 15, 2007 THE ONLY WAY YOU CAN LENGTHEN OR SHORTEN .... I HAVE TWO OF THE THREE COMBINED ... WOULD THAT BIND A CAR UP IN THE MIDDLE OF THE TURN ..THERFORE SLOWING IT DOWN ... Link to comment Share on other sites More sharing options...
NickHolt Posted December 15, 2007 Report Share Posted December 15, 2007 OT, Without knowing the linkages you employ in your car, I would hate to speculate if there are any binds present in your suspension. However, if you put the car on jackstands, take the springs out and undo the sway bar(s), you can jack up each wheel to check for any binding. Binding in a race car produces an unknown amount of effective spring rate at the corner that is binding. Sometimes a certain amount of binding (such as anti-squat) can help more than it hurts, but for the most part any suspension binding that is needed to get a car to handle is simply a crutch to compensate for another problem in the suspension. Nick Link to comment Share on other sites More sharing options...
poorboy Posted December 15, 2007 Report Share Posted December 15, 2007 Ok Nick that is what I always thought. Link to comment Share on other sites More sharing options...
HiTech Posted December 15, 2007 Author Report Share Posted December 15, 2007 nick i agree with your assesment ..what you said i did .. everything is fine Link to comment Share on other sites More sharing options...
thumper Posted December 16, 2007 Report Share Posted December 16, 2007 OT,this is what is now outlawed at CC Speedway for Thunder cars.The rear oversteer was a help to live axle cars that pushed because of a high front weight percentage.It helped the FWD cars the same way for the same reason.Rear understeer has always been a bad thing,it causes a push at entry and loose at exit under power.The larger the track the less rear steer is needed.At SAS stratght up was needed.On dry slick dirt rear steer is used with body roll and all the left side weight is jacked into the LR so without roll steer they could not turn.Thats why the LF is in the air and the LR almost under the driver.You can get roll steer with leaf springs if you have soft springs and an arch in them.Coils rely on the locating arms.For the most part you dont need rear steer on pavement except like at CC Speedway where the speed is high and tires are poor.The down side of static rear steer with a locked diff is the drag created down the straights. Suspension binding is the worse thing for a race car.Rather than use a lot of anti-dive,I would prefer to use springs and bars.A little might help a pavement late model with large tires on corner entry but too much will overheat the front tires in a long race.I dont know anyone who uses anti-dive on dirt modifieds in front or rear.On the contrary,they want the car weight to move all around.I think roll oversteer could be helpful at Thunderhill especially in turn one.I would not want static oversteer there.JMO. Link to comment Share on other sites More sharing options...
poorboy Posted December 16, 2007 Report Share Posted December 16, 2007 Static rear steer can still be put on a front wheel drive car without lengthening the right side wheel base, It can be done by changing the thrust angle and is virtually impossible to tech without an alignment machine at the track . So a rule that says no rear steer is just stupid. Link to comment Share on other sites More sharing options...
HiTech Posted December 16, 2007 Author Report Share Posted December 16, 2007 OT,this is what is now outlawed at CC Speedway for Thunder cars.The rear oversteer was a help to live axle cars that pushed because of a high front weight percentage.It helped the FWD cars the same way for the same reason.Rear understeer has always been a bad thing,it causes a push at entry and loose at exit under power.The larger the track the less rear steer is needed.At SAS stratght up was needed.On dry slick dirt rear steer is used with body roll and all the left side weight is jacked into the LR so without roll steer they could not turn.Thats why the LF is in the air and the LR almost under the driver.You can get roll steer with leaf springs if you have soft springs and an arch in them.Coils rely on the locating arms.For the most part you dont need rear steer on pavement except like at CC Speedway where the speed is high and tires are poor.The down side of static rear steer with a locked diff is the drag created down the straights. Suspension binding is the worse thing for a race car.Rather than use a lot of anti-dive,I would prefer to use springs and bars.A little might help a pavement late model with large tires on corner entry but too much will overheat the front tires in a long race.I dont know anyone who uses anti-dive on dirt modifieds in front or rear.On the contrary,they want the car weight to move all around.I think roll oversteer could be helpful at Thunderhill especially in turn one.I would not want static oversteer there.JMO. i didnt know how much it would help fwd .. ..sas strieght up // thunder hill helps to have it .but im thinking it maybe hurting in the middle at kyle .. .. thats why i want to go practice at kyle .. turn four at cc is the hardest i have seen ..that is the toughest ...you get off that turn really good and you have them whiped ..but you give up something in turn two ..if you notice the rear wheel drive get off turn two really good ..very few off 4 .. as for as role stear ... my springs are not considered soft .for this car ..POORBOY that rule will keep one of our cars off the track ..at cc . Link to comment Share on other sites More sharing options...
poorboy Posted December 16, 2007 Report Share Posted December 16, 2007 Role center isn't straight???? Nick HELP!!!!!!!!!!!!!!!!!! Link to comment Share on other sites More sharing options...
HiTech Posted December 16, 2007 Author Report Share Posted December 16, 2007 Role center isn't straight???? Nick HELP!!!!!!!!!!!!!!!!!! whups lol that wasnt suppose to be there . thats another subject .. Link to comment Share on other sites More sharing options...
neon14 Posted December 16, 2007 Report Share Posted December 16, 2007 I tell you there is one thing that is set up just right, and thats oldtimers computer and keyboard lol Link to comment Share on other sites More sharing options...
NickHolt Posted December 16, 2007 Report Share Posted December 16, 2007 Role center isn't straight???? Nick HELP!!!!!!!!!!!!!!!!!! Poorboy - That's why I'm here - to help in a grandfatherly kind of way. But let me tell you, those pesky curved or crooked roll centers can cause all kinds of havoc. I knew a guy who had an oblong roll center once. Caused his '49 Studebaker Super Late Model to bounce down the track like tricycle with a bent rear wheel. Most knowledgable suspension engineers have since learned to use sine-curve shaped roll centers to coincide with the driver's breathing. Lots of data acquistion stuff is needed to get it right, but hey, if you can get the driver's breathing and the frequency of the roll center coordinated, why, there's no telling how fast a race car - especially a Ford 4-cylinder race car - could go. And the beauty of this setup is that it doesn't matter if the roll center is crooked just as long as it's sine-curve shaped... WOW! What a deal! P.S. Been snipe hunting lately? Nick Link to comment Share on other sites More sharing options...
HiTech Posted December 16, 2007 Author Report Share Posted December 16, 2007 Role center isn't straight???? Nick HELP!!!!!!!!!!!!!!!!!! Poorboy - That's why I'm here - to help in a grandfatherly kind of way. But let me tell you, those pesky curved or crooked roll centers can cause all kinds of havoc. I knew a guy who had an oblong roll center once. Caused his '49 Studebaker Super Late Model to bounce down the track like tricycle with a bent rear wheel. Most knowledgable suspension engineers have since learned to use sine-curve shaped roll centers to coincide with the driver's breathing. Lots of data acquistion stuff is needed to get it right, but hey, if you can get the driver's breathing and the frequency of the roll center coordinated, why, there's no telling how fast a race car - especially a Ford 4-cylinder race car - could go. And the beauty of this setup is that it doesn't matter if the roll center is crooked just as long as it's sine-curve shaped... WOW! What a deal! P.S. Been snipe hunting lately? Nick hey ive sniped hunted .i baged a tick .. Link to comment Share on other sites More sharing options...
poorboy Posted December 16, 2007 Report Share Posted December 16, 2007 Thanks Nick, so thats why my car pushes when I hold my breath. Link to comment Share on other sites More sharing options...
NickHolt Posted December 16, 2007 Report Share Posted December 16, 2007 Thanks Nick, so thats why my car pushes when I hold my breath. Yep. But on the other hand, breathe too fast and you're loose! And never, I repeat NEVER allow any flatulance escape once the breathing rate and the sine-shaped roll center are working in unison. It'll stink up the handling in a hurry... Nick Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.