ES,
Look up Ackerman steering and you will see that there are some of both. Depends on many factors and suspension settings. Does your car oversteer or understeer is a more appropriate question. It's been years since I had to set up a suspension but I was a licensed front end and brake mechanic along with being a licensed smog mechanic in California when I was a kid. I got those licenses just for myself so I could work on my own cars, I could pass my own car. Only thing I never mastered on cars was upholstery, done it all from building cars for customers to building tooling to produce composite bodies. I find it funny what people believe about car companies, take apart a BMW or Mercedes and you will find all the shared parts, even GM and Ford shared parts back and forth. By the way dvv those Rochester carbs were GM carburetors. I think I had to take every different type of carburetor apart and put them back together in spec in class, the worst were the British carbs, who in hell came up with the oil damped carb idea, have you checked the carb oil level in your MG or Triumph lately! SU and Solex you can keep.
Give me fuel injection, Bosch Injectors or give me Holley carburetors. They still make it illegal to install fuel injection on a carbureted engine in California, go figure that out. Your not allowed to make them run cleaner or more efficiently, those California Air Resources Nazi's take all the fun out of older hot rods.
Look up Ackerman steering and you will see that there are some of both. Depends on many factors and suspension settings. Does your car oversteer or understeer is a more appropriate question. It's been years since I had to set up a suspension but I was a licensed front end and brake mechanic along with being a licensed smog mechanic in California when I was a kid. I got those licenses just for myself so I could work on my own cars, I could pass my own car. Only thing I never mastered on cars was upholstery, done it all from building cars for customers to building tooling to produce composite bodies. I find it funny what people believe about car companies, take apart a BMW or Mercedes and you will find all the shared parts, even GM and Ford shared parts back and forth. By the way dvv those Rochester carbs were GM carburetors. I think I had to take every different type of carburetor apart and put them back together in spec in class, the worst were the British carbs, who in hell came up with the oil damped carb idea, have you checked the carb oil level in your MG or Triumph lately! SU and Solex you can keep.
Give me fuel injection, Bosch Injectors or give me Holley carburetors. They still make it illegal to install fuel injection on a carbureted engine in California, go figure that out. Your not allowed to make them run cleaner or more efficiently, those California Air Resources Nazi's take all the fun out of older hot rods.
Kindy,
Ackermann steering was a great invention. But it doesn't affect the rear wheels. It does allow matching the turning radius for the front and rear wheels at certain radii in practice. Radius correction is great for turning corners not so much for driving in a large diameter circle as it is rarely done.
That is why I put in the qualifier at much greater than the wheel base. (Also please read the devious question exactly!)
BTY my college used to have races with manned unpowered vehicles that were pushed up hills and rolled down them. The fastest ones only use three wheels to avoid steering geometry loses.
Ackermann steering was a great invention. But it doesn't affect the rear wheels. It does allow matching the turning radius for the front and rear wheels at certain radii in practice. Radius correction is great for turning corners not so much for driving in a large diameter circle as it is rarely done.
That is why I put in the qualifier at much greater than the wheel base. (Also please read the devious question exactly!)
BTY my college used to have races with manned unpowered vehicles that were pushed up hills and rolled down them. The fastest ones only use three wheels to avoid steering geometry loses.
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depends on the slip angle of the rear (unsteered) wheels and the radius of turn:wheelbase ratio.
And for those that think slip angle only applies at higher speeds.
Any wheel that is generating a side force will slip relative to the straight ahead direction.
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ES,
That also depends on whether your talking a solid axle or independent suspension and the type of attachment points. A simple half shaft rear suspension can have different toe movements on either side depending on the complexity of the suspension. Your not saying how fast or what radius except for greater than a minimum turning radius. You have toe angles, camber curves and slip angle as AndrewT just brought up. And don't forget tire pressure differentials due to how long your going around the circle, inner to outer tire temps. It can get pretty complex just looking at one end of the car and now add in both ends and things get rather complex. Just take a look at a circle track cars setup sometime and how the tiniest change can completely change the handling of the car. Track bars, Watts links, four bar, three bar, take your pick.
That also depends on whether your talking a solid axle or independent suspension and the type of attachment points. A simple half shaft rear suspension can have different toe movements on either side depending on the complexity of the suspension. Your not saying how fast or what radius except for greater than a minimum turning radius. You have toe angles, camber curves and slip angle as AndrewT just brought up. And don't forget tire pressure differentials due to how long your going around the circle, inner to outer tire temps. It can get pretty complex just looking at one end of the car and now add in both ends and things get rather complex. Just take a look at a circle track cars setup sometime and how the tiniest change can completely change the handling of the car. Track bars, Watts links, four bar, three bar, take your pick.
It is unfortunate Richard that the whole thread around CFA and VFA became corrupted by a small core of individuals who either insisted there was no such thing as a CFA (Mr M IIRC) and another cabal who vented anti CFA spleen at every opportunity.
That CFA's, as a topology, can easily match or exceed VFA amplifiers I think is no longer in any doubt thanks to the doers on the forum.
That CFA's, as a topology, can easily match or exceed VFA amplifiers I think is no longer in any doubt thanks to the doers on the forum.
Bonsai,
It seems that B. Cordell has come around about at least looking at and analyzing the CFA but D. Self is still throwing flames that direction. So it comes down to if you have an open mind or an agenda to fight against the application of CFA designs. Scott has pointed out many times that CFA designs are in many opa's.
It seems that B. Cordell has come around about at least looking at and analyzing the CFA but D. Self is still throwing flames that direction. So it comes down to if you have an open mind or an agenda to fight against the application of CFA designs. Scott has pointed out many times that CFA designs are in many opa's.
technical Forum for cars/automobile suspension suggestions
Since cars keep coming up here, there are a lot of you interested in them.
Can some of you point me to some good car suspension Forums where techy questions and answers are handled in an expert fashion, much like we do for amplifiers here.
I joined two VW Forums just after I bought my first Golf. A complete waste of my effort, They know next to nothing and VW never come in to any conversation to confirm, nor deny, any "theories" on how some THINK their cars behave.
I have quite a few questions on anti squat and anti dive and toe changes for live and dead axles.
I have even more questions for the same three topics for independent suspensions.
Since cars keep coming up here, there are a lot of you interested in them.
Can some of you point me to some good car suspension Forums where techy questions and answers are handled in an expert fashion, much like we do for amplifiers here.
I joined two VW Forums just after I bought my first Golf. A complete waste of my effort, They know next to nothing and VW never come in to any conversation to confirm, nor deny, any "theories" on how some THINK their cars behave.
I have quite a few questions on anti squat and anti dive and toe changes for live and dead axles.
I have even more questions for the same three topics for independent suspensions.
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Whilst I am a DCOE weber guy on my fun cars at least SUs are easier to get your head around. The mythical 3" SU that powered the rolls Royce merlins was a mighty thing. Only ever seen one in the flesh.
Veering completely off topic. I had a phase of playing with adding engine management to kit cars. With that re-using OEM parts was the order of the day and the biggest boon of all was the ford EDIS unit for ignition control. A thick film hybrid sunk in some jelly like goop that doesn't harden and allows you to rework in situ. Easy to control without a complex ECU and will happily run all day underwater. One of the best things ford ever did for the hobbyist.
Andrew,
I don't know if it is still in print and available but GM/Chevrolet's performance division had a great book at one time giving all the technical analysis and even setup information for suspensions. I haven't seen my book in a long time but I had one and also some on race car design and setup. I knew people who raced circle track cars and road racers so had a ready supply of suspension experts at one time but haven't done that on the net. I'd imagine such a group exists, I know that a friend raced his Jetta back in the day and there were groups for just those cars.
I don't know if it is still in print and available but GM/Chevrolet's performance division had a great book at one time giving all the technical analysis and even setup information for suspensions. I haven't seen my book in a long time but I had one and also some on race car design and setup. I knew people who raced circle track cars and road racers so had a ready supply of suspension experts at one time but haven't done that on the net. I'd imagine such a group exists, I know that a friend raced his Jetta back in the day and there were groups for just those cars.
Andrew: Let me see if someone I know who actually knows his onions is able to help you. Will PM you. He can also teach you how to drive more proper if you feel so inclined.
I do keep meaning to buy his MX-5 which has this on it RE: PH Fleet Update: Mazda Eunos Roadster - Gassing Station - PistonHeads
I do keep meaning to buy his MX-5 which has this on it RE: PH Fleet Update: Mazda Eunos Roadster - Gassing Station - PistonHeads
Stromberg is quite a good damped piston (constant depression) carburetor.
The damping is there to delay the piston rising and thus generates a "bit more sook" to help the petrol stream enter as the throttle is opened quickly. I.e. acceleration enrichment.
Even weber/delorto had an acceleration enrichment.
Back to the Stromberg.
I had two 1¼" Strombergs fitted as standard to my Sunbeam Sport. Only 50BHP from 875cc with an 8valve head.
Yet it has been my most economical car until I got this common rail 1600cc turbo diesel Golf.
All my other turbo and non turbo diesels could not better that 1974 technology for fuel consumption.
I borrowed all the car books that had at least a chapter on car suspension from my library.
None properly explained much that I have learned since.
The 750 Motor Club had a magazine in which Adrian Reynard (when he was still designing Formula Ford cars) showed us how to design the independent suspension of a racing car. Unfortunately I only got to see part4 of the series of articles, since I was not a Member. I could see he was good and knew what he was talking about. Little did I know just how famous he was to become ! (now I'm not sure I have the right author, it was a long time ago)
I turned Alan Staniforth's "string computer" into a GWbasic programme, to allow me to quickly calculate independent suspension (only unequal non parallel links). It took me about half a day to calculate the roll centre height of an IRS using manual/longhand calculation. An 86 (maybe a 286) running at about 1Mhz could do that in about 2seconds back in 1988 and show me a little 2D black and white diagram to confirm I had the links and pick up points in the right locations..
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Kindy,
The hook was that it is the rear axle that determines the center of the turning circle. The front is the typical steering point and the various alignment techniques are to have the fronts track that center point under varying conditions including slippage and body movement.
You did get that Ackermann was the first to figure it out. I can't tell you how often I present this problem to the mathematically inclined and watch the results.
In a perfect alignment the front tires will not be in exactly the same tracks as the rear due to the length offset. They will have the same center point. Now will they be inside or outside of the matching rear wheels when tracking without slippage or body roll?
ES
Holley and other American carbs had accelerator pump circuits, never needed to add fluid damping to make those work. You could change the shot size and the shot timing very easily. Why make anything more complex than necessary and why need the constant maintenance is the real question? I guess it is as always the American designs are meant to be simple and just work, European designs just seem to want to add some elegance to a simple solution, added complexity for no real gain in final usage. Don't get me wrong, I can appreciate an elegant design and nice looking parts but many times simplicity wins in the end with less maintenance and service life. Yes a row of Weber carbs looks nice but having to synchronize them is a pain, just like a row of carbs on a motorcycle, same process of looking at equal vacuum drop across multiple carbs.
when it talks like a bunch of immature fanboys...
wow does that have all the markers of fanboyism wrapped up in one concise post!
I objected to and pointed out the repeated pattern of claims for CFA advantages that in fact were not exclusive to that topology
to a fanboy everything good under the sun is attributed to their object of admiration
to a fanboy unthinking Loyalty is a absolute requirement
any attempt to add perspective, place it in a larger context is an attack
in discrete audio power amps compensation is able to be tailored - CFA op amp let you do it externally with feedback Z - in discrete design VFA compensation can be varied however justified
CFA do cut a pole out of the forward gain path - discrete power audio power amps are generally limited by output device speed, packaging, wiring
so the faster small signal stage is of limited advantage
the CFA thread mixed in the minimalism rhetoric as well - but when you want low audio distortion you need high loop gain which requires compound transistors, cascodes, "Super Pair"...
and of course there is Richard Clark's, Carver's "challenges" - Geddes using $200 chip amped Pioneer home theater amps...
given all of that maybe CFA fanboys should just chill - we are handily past audibly critical choices in audio power amp design, into "conceptual art" designs, builds just to please our eyes and brains with topology, parts choice, artistic execution
wow does that have all the markers of fanboyism wrapped up in one concise post!
I objected to and pointed out the repeated pattern of claims for CFA advantages that in fact were not exclusive to that topology
to a fanboy everything good under the sun is attributed to their object of admiration
to a fanboy unthinking Loyalty is a absolute requirement
any attempt to add perspective, place it in a larger context is an attack
in discrete audio power amps compensation is able to be tailored - CFA op amp let you do it externally with feedback Z - in discrete design VFA compensation can be varied however justified
CFA do cut a pole out of the forward gain path - discrete power audio power amps are generally limited by output device speed, packaging, wiring
so the faster small signal stage is of limited advantage
the CFA thread mixed in the minimalism rhetoric as well - but when you want low audio distortion you need high loop gain which requires compound transistors, cascodes, "Super Pair"...
and of course there is Richard Clark's, Carver's "challenges" - Geddes using $200 chip amped Pioneer home theater amps...
given all of that maybe CFA fanboys should just chill - we are handily past audibly critical choices in audio power amp design, into "conceptual art" designs, builds just to please our eyes and brains with topology, parts choice, artistic execution
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Ackerman requires Zero slip angle.
That's why we have some vehicles with less than ideal Ackerman, some with more than ideal Ackerman and some that even have negative Ackerman, Yes the steered wheels toe in as the steering turn angle increases from the straight ahead. Ideal Ackerman toes out the wheels so that both point in, such that the axle line points back towards that theoretical turn point.
They will not have the same centre point.
That could ONLY hold true if ideal Ackerman existed for all vehicles and ALL tyres had Zero slip angle. But they don't have zero slip angle, so ideal Ackerman does not allow the tyres to have the same centre point.
And that is why most vehicles do not adopt ideal Ackerman.
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There are innate advantages to CFA topology. Are they all important? All else being equal, they probably are. Look at the OPEN LOOP BANDWIDTH between VFA and CFA. There will be a significant difference, and CFA has inherently higher open loop bandwidth.
On the other hand, VFA might actually have lower static distortion due to higher open loop GAIN.
On the other hand, VFA might actually have lower static distortion due to higher open loop GAIN.
Not setting my hopes to high, but perhaps this time you would care to provide an answer: what exactly do you mean by "easier to compensate for stability"? From your previous attempt, my impression was that you mean "compensating without having a clue of what I am doing".
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