Spherical "Bushings"

>> is a dial indicator

That requires a tear down. Not gonna happen. Might be easy to pull the VC on a Golf but on many cars its a very large undertaking. Plus after seeing the tear downs that have happened I have no confidence that cam profiles could be measured properly at an event by voluteers with no prior experience doing so.

COMPRESSION GAUGE AND DISPLACEMENT PUMPS !
:bash_1_:
COMPRESSION GAUGE AND DISPLACEMENT PUMPS !
:bash_1_:
COMPRESSION GAUGE AND DISPLACEMENT PUMPS !
 
Originally posted by Bildon@Jan 24 2006, 04:36 PM
>> is a dial indicator

That requires a tear down.  Not gonna happen.  Might be easy to pull the VC on a Golf but on many cars its a very large undertaking.  Plus after seeing the tear downs that have happened I have no confidence that cam profiles could be measured properly at an event by voluteers with no prior experience doing so.

COMPRESSION GAUGE AND DISPLACEMENT PUMPS !
:bash_1_:
COMPRESSION GAUGE AND DISPLACEMENT PUMPS !
:bash_1_:
COMPRESSION GAUGE AND DISPLACEMENT PUMPS !
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The problem with both of those is that they don't usually work. I'm not sure what you would do with a compression gauge - there are way too many variables to have the PSI generated in the cylinder by the starter motor mean anything.

And the displacement pumps are great in NASCAR, where all of the engines have rocker arms, but really hard to implement in sports car racing, where most of the engines have overhead camshafts operating directly on the valve lifters. Don't forget, for one of those gizmos to work, you have to disable the valves for at least the cylinder you're checking. That's very hard on most all of the cars that we race.

Cheers,

Chris Camadella
ITS Porsche 944
 
Bill Miller, if ya want to continue the jack jawing about suspension bushings & spherical bearings please go to the PCS rules & explane the two rules to me. The pcs bushing material rule is the exact same words as the IT rule & the other PCS rule talks about bearings. ;)
 
I know we've seen a lot of opinions on the bushing replacement issue, but I'll add mine anyway.

I firmly believe that the spherical bearings in a car I know about are perfectly legal within the current spirit of the rules, although I do agree that a rewrite is necessary, because I don't think they're legal within the LETTER of the rules, which, it turns out, is the only thing that matters.

1. 17.1.D.4.5.d.6 says "Bushing material, including that used to mount a suspension subframe to the chassis, is unrestricted".

2. A BUSHING is actually something that takes up space. Look at the definitions in the glossary section. That is also the accepted engineering definition of a bushing.

3. A BEARING is something that allows two parts to turn relative to one another without unduly wearing out the parts. Some bearings have more friction than others, but if the parts move, they're all bearings. Since the suspension moves up and down, even the rubber suspension 'bushings' are actually bearings.

4. It is obvious that the rule makers meant 'bearing' when they said 'bushing'. Look at section 17.1.D.4.5.d.1, 2, and 3. If you can adjust camber with an eccentric 'bushing', then that 'bushing' must allow for movement, which makes it a bearing.

5. Provided that you accept that the rules writers were talking about those big rubber things that this car (the one I know about) has at the control arm pivot point when they meant 'bushing' (which I think they did), then the ones in my friends' car are legal, as follows:

a. They are dimensionally identical to the original parts. They have the same ID, the same OD, and the same length. Neither the control arm nor the suspension crossmember to which the arm attaches have been modified in any way.

b. They use the same mounting hardware, in the stock location.

c. They are made of an alternate material (or, in this case, materials, plural, which happen to consist of aluminum, stainless steel, and a little tiny bit of teflon. The rules don't say that the 'bushing' has to be homogeneous.)

I guess I, for one, don't even see any gray area in these items. I believe that the parts mentioned above are legal within the current rules.

Cheers,

Chris Camadella
ITS Porsche 944
 
This threads reminds me of why I so enjoyed Wednesday night bracket racing at the local drag strip. You post your ET on the window and if you run 0.10 sec under you go home. The round-robin winner goes home with 50 bucks.

I think we should do this with lap times. :D
 
Originally posted by ChrisCamadella@Jan 24 2006, 12:33 PM
I know we've seen a lot of opinions on the bushing replacement issue, but I'll add mine anyway.

I firmly believe that the spherical bearings in a car I know about are perfectly legal within the current spirit of the rules, although I do agree that a rewrite is necessary, because I don't think they're legal within the LETTER of the rules, which, it turns out, is the only thing that matters.

1.  17.1.D.4.5.d.6 says "Bushing material, including that used to mount a suspension subframe to the chassis, is unrestricted".

2.  A BUSHING is actually something that takes up space.  Look at the definitions in the glossary section.  That is also the accepted engineering definition of a bushing.

3.  A BEARING is something that allows two parts to turn relative to one another without unduly wearing out the parts.  Some bearings have more friction than others, but if the parts move, they're all bearings.  Since the suspension moves up and down, even the rubber suspension 'bushings' are actually bearings.

4.  It is obvious that the rule makers meant 'bearing' when they said 'bushing'.  Look at section 17.1.D.4.5.d.1, 2, and 3.  If you can adjust camber with an eccentric 'bushing', then that 'bushing' must allow for movement, which makes it a bearing.

5.  Provided that you accept that the rules writers were talking about those big rubber things that this car (the one I know about) has at the control arm pivot point when they meant 'bushing' (which I think they did), then the ones in my friends' car are legal, as follows:

a.  They are dimensionally identical to the original parts.  They have the same ID, the same OD, and the same length.  Neither the control arm nor the suspension crossmember to which the arm attaches have been modified in any way.

b.  They use the same mounting hardware, in the stock location.

c.  They are made of an alternate material (or, in this case, materials, plural, which happen to consist of aluminum, stainless steel, and a little tiny bit of teflon. The rules don't say that the 'bushing' has to be homogeneous.)

I guess I, for one, don't even see any gray area in these items.  I believe that the parts mentioned above are legal within the current rules.

Cheers,

Chris Camadella
ITS Porsche 944
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Thanks Chris, I have not posted cause I am not smart enough to say it this way, the best and clearest points on the subject yet.
 
Chris you correct, the pump I described would not work for most IT cars. :unsure:
I am sometimes blinded by my own experiences...(or lack thereof)
On non-interference (VW) engines with timing belts...this test would not be so hard.
There is another type of displacement pump that fills the TDC cylinder with compressed air and measure that volume as it fills... I have not see these in person...has anyone? Sounds like it would be far more $ however. :(

However on the compression gauge issue... We all have factory manuals with a range of acceptable compression readings listed...from worn cylinders to new fresh ones.

With all your peers looking on, I think a pressure reading that was WAY out of spec. would keep a lot of people in check. :bash_1_:
 
On one hand, I like the idea Bill. I know a few guys that would fake an off during a session if they knew they were going to get "burped" in impound right after. And that's just this year! ;)

On the other and, IF it's not reasonably accurate, I hesitate to go to all the trouble, and possibly creat bad blood where there should be none.

Last year Anthony Serra, who owns The Mechanics Shop on lower NY state sopnsored a set of prizes to be won in the years big race at Lime Rock, the NARRC Runoffs. Fastest Honda/Acura got some money, second got less, and so on, or something like that. But the cool part was, you drove your car from impound to Anthony's paddock area where he hung out while Jason, his mechanic, did compression tests and checked cams. Cool stuff, LOL, and everybody who took part was clean...even Richie! (Kidding Richie! ;) )

It's tough on tech to do that much checking, but I would be all for a plan that is robust, dependable, accurate and relatively low stress on all concerned.
 
Although Chris' logic and clarity are to be commended, I have to beg to differ on a couple of assumptions and the conclusion that follows from them.

I am absolutely certain that the rulesmakers did not mean "bearing" when they said "bushing." They did not use the extremely technical definition that Chris does. Geez, if you run w/ that I guess a tire is a bearing, as are every other pair of things that turn against each other. As I have said before in this thread and no one has wanted to acknowledge, the glossary first and foremost defines a bushing as a "sleeve or tubular insert." Since a tire is neither, and nor are any other of a multitude of examples that would fall w/i Chris' definition of bearings, his premise breaks down. Thus, even if Chris is correct in the most esoteric sense of what a bearing truly is, this rule is talking about something more limited. Perhaps a subset of bearings (i.e. all bushings are bearings but all bearings are not bushings). All this rule says is that you take an OEM bushing that is made of X and you can substitute one made of Y. While the rule does not use the term "homogenous" IMO the terms "sleeve" and "tubular" suggest as much. It says nothing about a sleeve or tubular insert w/ some kind of rotating joint inside. Now, I admit that the rule has been interpreted to allow multiple sleeves of different materials instead of one homogenous one, but I don't think that opens the door to a bushing of completely different design - one that ceases to be a simple sleeve or tubular insert.

I looked at a buddy's car yesterday that had just been fitted w/ sphericals all around but (other than they are eccentric and allow independent rear camber adjustment) I still don't quite understand why he spent so much $ on them. Thinking about the rear arms, when the suspension is in compression or bump the arm rotates vertically against the bushing in the housing - right? If all you wanted was less friction for that movement, wouldn't a sealed roller bearing like the wheel bearing do? But I suppose that the arm also wants to move somewhat laterally as well - right? And the roller would not allow that like the OEM rubber or whatever that has some "give." So, a spherical bearing allows ease of movement in both planes? But why would you really want your rear wheels to move laterally? Seems to me like all you'd want would be enough "give" to isolate the shock. What am I missing? Is it that you’d rather the rear wheels move than the entire car pivot? More camber adjustment? :119:
 
Binding.

When certain suspension designs are used at ride heights other than they were designed for the plane of movement tilts, especially when your rear suspension components have 10 pivots per side.

I have heard universaly that the 240SX will not run up front without spherical bushings in the rear suspension, period. I have been told time and again that if you don't have spherical bushings on the 240SX you are not fully prepared.

Now with the recent weight adjustments based on fully prepared vehicles, the question I have is were the ITAC recommendations based on spherical bushings being legal or illegal espcially when it matters tremendously in determining the suspension design benefit/detriment?

I continue to believe they are legal - but if they were determined to be illegal through a protest and only the mods suggested by the anti-SB camp then the 240SX was just shuffled to the rear when they gained 100lbs no matter how well prepared and driven against other fully prepped and well driven models.
 
Greg is right. That level of consideration for suspension design is not taken into account.

No worries though. The issue was discussed on our con-call... ;)

AB
 
Greg, you answered the question you wanted to not the question I asked, out of context quotes should at least remove the identity as the question was yours not mine.

Andy, so if I am to understand correctly the suspension benefit/detriment portion of the process did not consider how the suspension responds in IT legal prep?
 
Originally posted by turboICE@Jan 26 2006, 12:07 PM
Now with the recent weight adjustments based on fully prepared vehicles, the question I have is were the ITAC recommendations based on spherical bushings being legal or illegal espcially when it matters tremendously in determining the suspension design benefit/detriment?
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Ah! Given that the answer is...

...still "no".
 
Originally posted by turboICE@Jan 26 2006, 12:33 PM
Andy, so if I am to understand correctly the suspension benefit/detriment portion of the process did not consider how the suspension responds in IT legal prep?
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Yes, but not to the point of interpreting grey-ares rules to see how they could apply. The 'process' is not that sophisticated, nor should it be.

AB
 
Greg, but the implication of the answer is different. Might be the same word but in the context of the question the answer IS different.
 
Originally posted by Andy Bettencourt@Jan 26 2006, 02:05 PM
Yes, but not to the point of interpreting grey-ares rules to see how they could apply.  The 'process' is not that sophisticated, nor should it be.

AB
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Nor do I believe it should. But if a suspension binds in IT prep would that have an affect on the process? A binding suspension is much different performance potential than one that doesn't bind, wouldn't you agree? My assumption is that the group viewed the 240SX suspension performance based on it not binding. Might be a fair assumption or not - but if the assumption is accurate the 240SX suspension doesn't bind only if spherical bushings are used. By implication the process by treating the 240SX suspension as nonbinding in IT prep would indicate that SBs were being used and the process only considered legal prep levels.
 
Originally posted by turboICE@Jan 26 2006, 01:09 PM
Nor do I believe it should.  But if a suspension binds in IT prep would that have an affect on the process?  A binding suspension is much different performance potential than one that doesn't bind, wouldn't you agree?  My assumption is that the group viewed the 240SX suspension performance based on it not binding. Might be a fair assumption or not - but if the assumption is accurate the 240SX suspension doesn't bind only if spherical bushings are used.  By implication the process by treating the 240SX suspension as nonbinding in IT prep would indicate that SBs were being used and the process only considered legal prep levels.
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I think saying that your suspension binds in IT prep is a little strong. Your suspension binds because you are trying to lower the car below what the factory intended. Same with soem VW's etc. Don't lower it that much.

Don't make too much out of this. Your weight in the reclass has nothing to do with a 'sophisticated' suspension. Torque/displacement and RWD were 'adders' IIRC.

AB
 
Fair enough. You have told me what contributed to the decision and those are fair adders. However if I have to ride around at a rally height of 7" due to suspension design limitations if SBs are not legal, then I think the poor suspension design should have been part of a full consideration, IMO.

As was said in the process thread - full prep was assumed in the process. To me full IT prep is lower the CG as much as legally possible. If you don't do that, well then it just isn't full IT prep any longer. The easiest way to lower CG is to lower the car to the allowed 5". 5 1/4" or 7" isn't full IT prep and the competitor should not expect to compete against fully prepped cars of the same class if they are not fully prepped. Full IT prep for suspension should have the same principles as a discussion of whether or not an engine and its exhaust have been fully prepped.
 
Originally posted by turboICE@Jan 26 2006, 01:07 PM
I have heard universaly that the 240SX will not run up front without spherical bushings in the rear suspension, period. I have been told time and again that if you don't have spherical bushings on the 240SX you are not fully prepared.
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I've heard the same thing Ed. I have to wonder though, while I'm guessing our cars probably benefit more from spherical bushings (due to our mega-link rear suspensions) do none of the other front-running cars need them to win? How about it Acura/Honda/Mazda guys, can your cars win races without the benefit of spherical bushings?
 
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