In a thread on the IRL Forum it has been mentioned that pull rod suspensions aren't condusive to road course racing therefore the G-Force may have an advantage when the league goes to road course racing ( no flames please just discussion ). I would like insider and other esteemed posters to discuss the pros/cons of pull rod suspension.
Gentlemen: The floor is yours............
SENÓR MODERATOR......
"Better To Be Judged By Twelve Than Carried By Six"
" Only Those Who Will Risk Going Too Far....Can Possibly Find Out How Far One Can Go "...T.S. Elliot....
I think the biggest disadvantage is a pullrod is more difficult to work on due to its location along the bottom of the chassis. Because of space limitations, the shocks need to be mounted almost horzontal. In a pushrod design, the shocks can be angled which might offer a mechanical advantage. Advantages for pullrods are lower center of gravity and the pullrod can be made thinner than a pushrod because buckeling is less of a concern.
The major disadvantage of a pullrod suspension is the inherent higher forces in the system. In a vertical loading at the wheel situation the major load bearing elements of a pushrod suspension are the pushrod and lower w'bone.
In a pullrod suspension the pullrod and the top w'bone are the major load bearing components under bump conditions. (look at the Dallara top w'bone and you will see what i mean)
It is the included angle between these two components that effect the forces in the system. The pushrod system has a larger included angle and therefore less loading than a pullrod system for a given vertical wheel loading.
Ball park force ratios (dependant on geometry, etc) are 1.4 for the
pushrod element and 3.0 for the pullrod.
The other advantage of the pushrod is that under bump movement the included angle stays fairly constant, whereas the pullrod decreases and the loads are further increased.
The Dallara fore/aft placement of the damper rockers helps in this area compared to the pullrod March's which where across the car.
The later versions had a theoretical 35% rising rate over 1" wheel travel to give about 10% at the wheel when a real load was added. This lost motion was partly caused by the pullrod stretching and as it formed one side of a shallow triangle and it allowed the suspension to "lozenge"
Increasing the riseing rate also increased the forces in the suspension and the pullrod had run it's course. For those of you
That had the "pleasure" of working on these cars, you will remember how difficult they where to setup on the pad as the high stiction made the cross weight change all the time. The next March, the 89 March/Porsche (my baby) had pushrod suspension.
The use of a pullrod suspension on a smooth fast banked track is not a problem as long as you know what you are dealing with. However, there where complaints about the mild bumps in T1 and T2 at Kentucky last year.
Bottom line is that the higher the loading in the suspension elements the higher the stiction in the joints and reduced compliance. I am sure that Dallara and there teams are working hard in this area and looking to put needle and roller bearings (or even "flexure's in some places) at every junction. G-force can also do this and maintain there advantage of mechanical front grip at lower speeds and rough corners.
The ability to quickly change front springs and dampers at an untested street course is a huge advantage.
239.260
It is my understanding that the Arrows F1 team had a pullrod suspension with o.k. results a few years back, can anyone go into further detail?
another Dr Who blast from the past ...
The biggest problem with pull-rods is....
We've got too many pull-rods running Indy Car racing today.
This sport would be much better off with fewer pull-rods.
"IRL" ... what IS that anyway?
J. Michael RinghamIndyCar® Series Indy Pro Series™
Vice President, Marketing
www.jonescams.com yankeegoback.com
I think you were lookin for "nim rod" ... they can be neither pushed or pulled ....Originally Posted by CamKing
No, I was thinking pull-rod.I think you were lookin for "nim rod" ... they can be neither pushed or pulled ....
If those guys in charge spent as much time trying to run Indy Car as they did pulling their rods, we wouldn't be in the mess we're in.
It has been my observation, in over 45 years of doing this, that some people are smart enough to make push rods, pull rods, leaf springs or whatever they have, work and run up front and some people can take the same parts and figure out how to be 10 MPH off the pace....... and its never been more obvious than the current IRL specracer formula.
.
http://indyroadsters.webs.com/
http://macmillersgarage.webs.com/
http://www.youtube.com/user/macmiller46241
I love any race car whose last name is "Special"
.
Interesting. You've just negated your entire litany of complaints against a common chassis and engine.
And supported it at the same time.
Not really. You seem to be concluding that there would be less difference if those unable to make good with the present equipment were allowed to do something different. The history of the sport indicates rather strongly that the well heeled, most talented extend the gap whenever change is introduced in a previously stable rules environment.
Not Really.
History in the sport shows that the top guys with all the money will always have an advantage, and the also-rans will always be also-rans.
All the rules for "equality" have never worked.
When ingenuity is restricted, Engineering dollars willl aways win.
Everytime the rules are made to favor Ingenuity over Engineering, the smart guys with the smaller pocket books have a better chance.
There is no racing series in the history of racing that has resticted the rules, and gained equality.
Leased engines, and spec chassis have never done anything but take away the option of out-thinking the competition you can't out-spend.
You can't name a successful top-tier racing series that uses spec engines and chassis.
Not in Circle track
Road Racing
Drag Racing
Boat racing
Motorcycle Racing.
GP2 is sucessful. And do not even try to say it is not major league.
Just how far is NASCAR away from being spec with the chassis?
Mac, as I see it, there is a difference between the two examples you posted:
WORK
and
TAKE
No matter what rule book it still seems that the teams that put the most effort and pride in their jobs do the best no matter what financial situation.
What's that???
Isn't that the racing series that claims to be,
"Formula one's strongest feeder series"
I guess you missed the "top-tier" part.
I'm not talking about feeder series.
spec engines and chassis are great for feeder series'.
They have no place in major league racing.
Go to the wind-tunnels in Mooresville, NC, and you'll see how spec the NASCAR COT's are.
Sorry, but that's not the case.
When you restrict the rules to spec engines and chassis like they've done in the IRL. Effort and Pride lose-out to money every time. There's no way around it, and history has proven it.
Cammy is correct!..........specracer rules are a feast for guys like Penske, Ganassi, et al who can afford to cheat ..... er, I mean, do "development" work at the "molecular" level. Smart rich guys can beat smart poor guys every time........ especially when there are no technical options.
Open the rules and the rich teams build cars noone else can have. Close the rules and rich teams microengineer every part on a spec car to gain that 1% advantage. Rich teams will perform better more often.
...and if you want a little peace, sometimes you gotta fight. You gotta walk throught the darkness before you stand in the light. Sammy Hagar.
I seem to recall a time where you praised the IRL engine rules as being very good at minimizing the effect of spending money? What changed your mind?
Certainly you won't ever eliminate the advantage of cubic dollars - but with spec rules with minimal open area's you at least minimize teh advantage of those dollars
and we've found that tech advances in these small open area's become available to all pretty quickly
some like Mac would say eliminate all the technology - the telemetry etc - and let real engineers and real drivers set up cars the old way - by feel, tire temps, paint on the undertray skids etc
which really solves nothing - the bigger, better funded teams will have more and better engineers and more and better drivers - and will still on most occaisions dominate
racing is not a perfect sport and no matter how we want to or try it will never be ...
today - car setups are often the deciding factor - not fancy parts - there is not a single thing today stopping ANY engineer and team - no matter how small - from discovering the right setup ... dollars can help find it, but testing is limited to all - and 7 post work, simulations, etc can only help so far
There are any number of ideas that could help level the field more ... one example - allow the bigger multicar teams additional testing IF they use/pay for a smaller team and driver to do it - and then require as part of the deal that the smaller team gets access to not only the setups from the test - but also gets access to the bigger teams setups at that track when they race there
Yes! communism! great idea! information and money from each pro level team, according to their ability, to each substandard team, according to their need.
Actually, If they insist on a spec car series it should be absolutely and totally spec.
All cars should be housed and maintained at the same facility, at THE INDIANAPOLIS MOTOR SPEEDWAY, and maintained by group of spec technoids employeed by the IRL. They should be transported to and from the track in IRL transporters and assigned by totally random draw at the track.
Any time you let these people take their specracers home with them, two things will happen. The smart guys will figure out how to cheat and make them faster and the dumb guys will figure out how to make them slower.
It would also be interesting to lock the cars up immediately after they qualify and make them start the race with the same engine, tires and setup that they qualified. Of course, they would have to get rid of the current stupid "unlimited do over" qualifying garbage.
Sorry, but that has never happened in the history of auto racing.
Spec engines and chassis will never lesson the advantage of cubic dollars, but they do take away the ability to use ingenuity to cut into that advantage.
For those not old enough to remember.
Ford came to Indy Car with an engine that couldn't be beat.
It was twice as much money as it's competitors. It could only be worked on by the Ford engineers, and Indy car wast fastly becomeing a series where everyone ran a spec sealed Ford engine.
In walked ingenuity.
With 1/10 of Ford's budget, a few really smart, but not very rich men developed the short-stroke Turbo Offy. It sold for less then half the ford, and could be built by anyone. It destroyed the Ford, and became the engine of choice for the next decade.
Spec racing rewards those with the ability to spend more, and punishes those with the ability to think outside the box.
That's not racing.
My mind never changed. The IRL's rules changed.
The original IRL engine rules were headed in the right direction.
Thier inability to inforce thier rules, and stabilize them are the main reasons we're stuck with this mess of a series we have now.
Taking ingenuity out of Indy gives you.
TCGR
TCGR
Penske
Penske
AGR
AGR
AGR
We use to see things like Scott Brayton putting the Buick on the pole, or Greg Ray qualifying second with money taped to his car.
Now everyone's all pumped up over Indy 500 winner Buddy Lazier qualifying for the back row.
The only reason the Buick was able to show well in qualifying was because the rules favored it. Your argument is faulty because it fails to acknowledge that a great deal of that so called out of the box thinking was concentrated on finding rules loop-holes.
Just so we are on the same page, tightly defined engine rules with some open areas for development was a good thing that promoted close racing where money couldn't guarantee a win, yet tightly defined chassis rules with some open areas for development is a bad thing and only helps the rich guys? Does that pretty much sum up your thoughts?
Also, how did that Buick do against the Mercedes 209? Seems to me the little guy running the Buick didn't have the horses of the Merc motor, and never had the reliability either.
If you're just going to pull stuff out of your arse without any facts to back it up, you'll need to go somewhere else. Your opinions are not fact, and infact are far from reality.
What loopholes did greg ray use to put his underfunded car on the front row?
What Loopholes did Blueprint racing use when they won in the IRL?
What loopholes did they use on the Turbo Offy?
What loopholes did they use on the Blown Offy?
What loopholes did they use on the Novi?
What loopholes did they use on the Judd?
Just show me a successful top-tier racing series that runs spec engines and chassis.
Glad to see you still have trouble understanding.
You misrepresented both the old IRL engine rules, and the present chassis rules. They are nothing close to each other, so your question makes no sense.
BTW, the head engineer on the Mercedes 209 engine now works down the road from me.
The Mercedes engine made about the same power as the buick, and if they tried turning it any higher it would break. It's big advantage was it's low COG, and the fact that is was designed off their CART engine and fit well in the chassis.
The Mercedes engine was based on a loophole that was written into the books one year earlier. Rules stability whould have kept that from happening.
Like I said. Money will always give you an advantage, but spec rules do nothing but tie the hands of those that don't have the money.
No spec rule has ever evened-out the competition, but they have destroyed more then a one series.
So to answer your first question,
No, we are not on the same page.
You haven't even found the book.
I would like to hear any stories on these if you don't mind telling!
Back on topic, CamKing, have you ever looked at the FASTRAK engine rules? They run to the tune of "you mess with it, you are fined and banned".
(http://www.fastrakracing.com/rules.php) What do you make of them?
Posting Permissions
Reply With Quote
Bookmarks