Calling all rules nerds,,,,,,

I have a few rules questions I want to throw out for feedback.....


1. Can I legally change the bolt pattern of my hubs via the use of spacers ( not saying that is a good idea, just asking )

2. If my car allows the rear tubes of the cage to go thru the back glass and the GCR allows rear bars to go thru bulkheads then can I do both? Any reason I can't modify or remove the enging cover if bars pass thru it?

3. Is any modification to the strut housing legal i.e. changing spindle height?

4. Is there any reason why an aluminum underbody plate or pan could not be used to "protect" the fuel lines?

5. If oil coolers can be added or subtracted could my oem cooler be deleted or moved from it's enging mounted setup to a remote setup?

IMHO:

1. Yes

2. Yes

3. No

4. No

1. Sure. Any wheel stud, bolt, and or nut is permitted. And Wheel spacers are permitted.
2. I think you can modify but not remove.
3. MacPherson strut equipped cars may substitute struts, and /or may use alternate inserts.
Yes if the modification is part of the strut and no other piece that is restricted.
4. I cannot think of any justification for what I think you are suggesting
5. Oil cooler(s) may be added or substituted. Location within the bodywork is unrestricted, provided that it/they are not mounted within the driver/passenger compartment.

Sure but I do not see where you could make a body modification to duct air to the new location.

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Originally Posted by Fastfred92

I have a few rules questions I want to throw out for feedback.....


1. Can I legally change the bolt pattern of my hubs via the use of spacers ( not saying that is a good idea, just asking )

2. If my car allows the rear tubes of the cage to go thru the back glass and the GCR allows rear bars to go thru bulkheads then can I do both? Any reason I can't modify or remove the enging cover if bars pass thru it?

3. Is any modification to the strut housing legal i.e. changing spindle height?

4. Is there any reason why an aluminum underbody plate or pan could not be used to "protect" the fuel lines?

5. If oil coolers can be added or subtracted could my oem cooler be deleted or moved from it's enging mounted setup to a remote setup?

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1 - At first, I thought the wheel spacer allowance would cover this, but that item is defined in a fairly specific manner in the technical glossary, and I don't see any mention of a bolt pattern change there. Having said that, IMO this would be within the spirit of the rules, given all the other allowances (diameter changes) in the "Wheel/Tire" paragraph.

2 - I'm thinking you're okay on the bulkhead pass-through, provided the two bars end up in the same location (common plate). Cut a hole in the engine cover to accomplish this? Yes. Remove the engine cover to do this? I wouldn't think so.

3 - Seems to me that changing spindle height (relative to the suspension pickup points) would not be legal. You're changing the basic geometry, and that's certainly against the spirit, if not the letter.

4 - No allowance here IMO, even in the usually cloak of "safety". You can after all, relocate the fuel lines if you think they're in danger of getting dinged.

5 - I would think the word "substituted" in the oil cooler paragraph allows precisely what you're seeking.

I'd say that while you can indeed use any strut, yeah, if it results in changing suspension geometry, then that rule trumps it and it's not allowed...

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Originally Posted by 924Guy

I'd say that while you can indeed use any strut, yeah, if it results in changing suspension geometry, then that rule trumps it and it's not allowed...

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Not to be a pain but what rule are you referring to that would trump the strut change.

9.1.3.d.8 - No other relocation of any suspension mounting point is permitted.

I think that is it. Dick, I've always wondered as well, where is the allowance for modifying the strut tube itself to accept for example wider bodied struts?? I've always assumed that was legal too but now can't find it............................

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Originally Posted by JeffYoung

9.1.3.d.8 - No other relocation of any suspension mounting point is permitted.

I think that is it. Dick, I've always wondered as well, where is the allowance for modifying the strut tube itself to accept for example wider bodied struts?? I've always assumed that was legal too but now can't find it............................

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9.1.3.5.b.2
MacPherson strut equipped cars may substitute struts, and /or may use alternate inserts Spring seat ride height loca­tion may be altered from stock. Remote reservoir struts and/or inserts are prohibited.
It would seem that if the spindle is part of the strut the spindles position relative to the rest of the strut would be unrestricted.
And by the way here is the definition of a pickup point.
Pickup point (Suspension) – The location of attachment of a suspension component on the frame or structure of the car. Pickup point is also re­ferred to as “pivot axis.”

Thanks Dick. Not to quibble, just hashing this out. But, I don't see anything there that says you can widen the strut tube body for example for wider struts?

Or are we calling the entire strut tube and not just the insert the strut? I'll have to look at the definitions on that.

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Originally Posted by JeffYoung

Thanks Dick. Not to quibble, just hashing this out. But, I don't see anything there that says you can widen the strut tube body for example for wider struts?

Or are we calling the entire strut tube and not just the insert the strut? I'll have to look at the definitions on that.

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may substitute struts, and /or may use alternate inserts

yes I think so

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Originally Posted by dickita15

9.1.3.5.b.2
MacPherson strut equipped cars may substitute struts, and /or may use alternate inserts Spring seat ride height loca­tion may be altered from stock. Remote reservoir struts and/or inserts are prohibited.
It would seem that if the spindle is part of the strut the spindles position relative to the rest of the strut would be unrestricted.

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I think I'm going to reverse my position on the strut/spindle issue... as you say, if the spindle is actually attached directly to the strut, it therefore would be legal to change the position of the spindle in my new opinion. I'm used to seeing (I own a Fiero) a strut, to which is attached a knuckle assembly with spindle. I had forgotten there were strut suspensions that attach the spindle directly to the strut itself.

Relative to Jeff's question, I agree with Dick again. The strut is not just an insert. In fact, I believe some (most?) OEM struts don't even have inserts... wasn't the insert originally an aftermarket invention aimed at keeping replacement costs down?

***I'm used to seeing (I own a Fiero) a strut, to which is attached a knuckle assembly with spindle.***

Gary, do the normal knuckle attach to the strut then weld the attachment so that you have " a substituted strut". :) Then move the spindle to the height you like.

***I'd say that while you can indeed use any strut, yeah, if it results in changing suspension geometry, then that rule trumps it and it's not allowed... ***

Scott, the spindle is not a pickup point therefore the suspension geometry is not changed. ;)

David - I think we're talking the same process here... after I posted, it dawned on me that even with the bolt-on knuckle/spindle like the Fiero you simply build a "shorter" strut by moving the attachment point for the knuckle further up the strut. You might eventually run into clearance limitations of some sort, but it would accomplish the same thing as the shortened strut/spindle that Fastfred is talking about on his 914.

Interesting.....I'm familiar with just two strut type cars. Mine (TR8) and 260z.

For the TR8, the strut tube and spindle are one piece, with the insert dropping down "inside" the tube. Additionally, the lower control arm, steering arm and, essentially, the sway bar (which also locates the strut) connect to it.

So am I right that the consensus is:

1. I can increase the width of the strut tube for larger bodied strut inserts under the idea that struts are free?

2. I would disagree -- but want to make sure that is the consensus -- that I can SHORTEN the strut tube and raise the spindle as that will move the locating points for the LCA, the steering and sway bar.

Am I warm, cold, hot, or just out in left field?

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Originally Posted by JeffYoung

Am I warm, cold, hot, or just out in left field?

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No you are catching on. It is common practice with our cars to replace the strut tube with a larger one and then to add material to the bottom of the strut. This allows the lower control arm to be brought back to level when the car is lowered.

As a side light sometimes the mounting for the part that tie rod attaches to which in turn bolts to the strut is altered which has the effect of changing the ackerman for supposedly better turn in although I think that works better in solo than on road racing.

Is it a desire for better bumpsteer control, extra camber and/ or more strut insert options to custom make a combined strut/ spindle?

How about fabricating it out of unobtanium for weight control?

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Originally Posted by dickita15

As a side light sometimes the mounting for the part that tie rod attaches to which in turn bolts to the strut is altered which has the effect of changing the ackerman .

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Or bump steer correction........

Another rules question while we are on a roll.....

So my door bars go into the door panel, i am allowed to gut the door short of outsdide handle etc.

Does this also include the vent widow as well?

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Originally Posted by Fastfred92

Another rules question while we are on a roll.....

So my door bars go into the door panel, i am allowed to gut the door short of outsdide handle etc.

Does this also include the vent widow as well?

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Nope! I originally thought it would, but if you look at the glossary section (under "window"), it clearly differentiates the wing window from the sliding window, and the rule allowing window replacement doesn't include the vent window.

Basically, the allowance is for the "door window" to be removed, and the definition of that clearly excludes the vent window.

Here's the rule allowing door gutting (bold/italic added by me for clarity):

In American Sedan, Improved Touring, Showroom Stock, Spec Miata, and Touring the door window glass, window operating mechanism, inner door trim panel, armrest, map pockets, and inside door latch/lock operating mechanism may be removed and the inner door structural panel may be modified, but not removed only if the door bars extend into the door cavity.

And the definitions:

Windows:
A. Door or Side - The opening where the window normally is raised or lowered in a door. Does not include a “vent” window whether fixed or movable.
B. Quarter (1/4) - On a 2-door or 4-door vehicle, the window to the rear of the rearmost door. Such windows are not generally raised or lowered, but they may be hinged and open to the rear. Quarter windows are not “rear” windows.
C. Rear - Rear windows are positioned at right angles to the longitudinal axis of the car.

But the ITAC is discussing an possible allowance to allow the driver's side vent window to be removed for egress purposes. The issue is that with halo seats, egress space is getting encroached upon. Watch Fastrack for updates.

Well the way I understand the progression of improvements in RX struts. First the larger tube was needed in order to get a shock that would handle decent spring rates. The only race shock insert that fits the stock strut is the Tokiko and that will not handle stiff springs.
Then as long as you are making a new strut why not add some material to the bottom to correct the lower control arm angle when you lower the car.
Altering the location of the tie rod to improve ackerman was the next innovation.
I really don’t know if the bump steer was improved by this. I have never heard anyone claim that.

Here's where I start to lose you guys I think:

Altering the location of the tie rod to improve ackerman was the next innovation.

I'm not sure that struts are free means we can later anything from the bottom of the spindle up to the shock tower, especially if it means changing suspension mounting points. Not trying to be difficult, just trying to understand the rule cause my front strut looks a LOT like an RX setup and some of the things you guys are doing would be of real benefit to me.

Thanks for the discussion on this by the way, has been helpful.

Okay, first stop saying it is a suspension pickup point. That has a very specific definition stated above.
The strut can be anything you want and if the bolt holes where the steering link attaches to the strut are in a different orientation than stock the steering action is altered. Someone smarter than I deduced that is the orientation was moved a few degrees it would change the steering input.
How much of the part is the strut depends on the design of the car. With my car it includes the tube and cap that contains the shock, the spindle which is integral to the part and the bottom section that bolts to the lower control arm and the steering link.
There is no modification to the steering link or either end of the lower control arm.

On #2 are you talking about going through the front bulkhead?

Blake

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Originally Posted by bamfp

On #2 are you talking about going through the front bulkhead?

Blake

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No, rear only. Mid engine car.

I guess I stand corrected on the spindle height, given that it's not a pickup point!

As for the bump steer correction - sounds like if you can accomplish it without modifying the steering arm on the knuckle, and using the stock tie rod end, then it's legal?!? But if you wish to, say, replace your stock tie rod ends with a heim joint, bolted with shims to the knuckle, then that's not legal, right? Because then you'd be replacing a stock part with non-factory - unapproved substitution. Correct?

If you can accomplish a change by changing the strut and just the strut I say it is legal but no other part may be modified.