Getting the best out of standard suspension components for touring driving today

I have one
Too bad I tossed the old ones

I’ve got old ones, but doubt it would be worth the cost of shipping them.

Understood, I don’t know how any of the economics might look at present, first I need to assemble test sections with hardware and see what technical gain is available.
Should have occurred this week but I got distracted by chocolate again.


I found a source of raw cacao, which gives me an excuse - sorry, that should read …compels me… to get Tools and Machinery for the processing thereof.

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You should feel no compunction to offer an apology: it is, after all, chocolate!

I know very little about the processing thereof, but I know that it’s actually pretty intense.

Probably the messiest task I’ve ever done. I believe I could service a battle tank in a swamp and emerge cleaner.

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But… but… chocolate!

:wink:

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I didn’t mean to suggest it was a problem - just a messy situation :upside_down_face:

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I bet @Robert_Laughton has a pile!

I do have some, but to fit which car?

I know some have different widths depending on model.

This is a long thread, got lost, sorry.
Rob

I kept my old ones from a 62 if they are of interest.

I think I have my rock hard originals and 2 from your first experiment. And probably a set of cheap ones that aren’t worth shipping.

Thanks for the responses, do we have the makings of a scrap metal world tour?

I should know if the general idea has merit within the next week. Got some mixiin’, pourin’ and compressin’ in my future.

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I have that same problem.
I’m working with XK-E parts.

Well I have a mount which is stiffer in vertical mode than anything I’ve found commercially. I expect the lateral mode will follow that pattern, will test shortly.

Next step is to massage the detail stiffness and dimensions so it will fit to the car freely without forcing, compressing, cursing, hospital visits or special devices.

Regular companions of the obscure will know that charts cannot be far behind.

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It’s been 10 minutes: we’re waiting!

:blush::wink::rofl:

About those mounts then…

…it might not come as a complete shock that I wandered down a side track. I was doing standard load-deflection tests on IRS mount sections when I noticed that some sections of polyurethane felt more “bouncy” than rubber, even in handling on the bench and fitting them to a jig for static test. I thought that worth pursuing, so made a crude bounce test to see if the difference was measurable. I put the test section on a slab of stone with a phone running the My Frequency app alongside, then dropped a 25mm steel ball from 100mm above (released by a small electromagnet for consistent force). The phone picks up the resulting vibration and gives a simple analysis of force vs time.
Crude picture of a crude process, ball rebounding up from first contact:

Not quite NPL standard but it did show some interesting differences between four materials - the following picture combines force vs time traces, with scales adjusted to be comparable:

  • baseline – steel on stone, no isolator. Short and sharp, as would be expected.
  • PU 80 Shore A hardness. Absorbs forces progressively, extending the event longer
  • Rubber 65 Shore A (original mount material). Similar and more so, with longer absorption time
  • PU 70 Shore A PU. Clearly less damping, showing little force reduction (absorption).

Is any of this significant? If the 70A PU behaviour carried over to a component – mount or bushing – it could feel imprecise or erratic. It has particular significance with the E-type because these bushings are above the suspension dampers, so the body is bouncing around on the mounts without the usual damper controls. A bit like mounting the seats on blocks of rubber – not the usual path to better contact and control. That’s why I think these mounts justify an extreme amount of study and test.

Comments and corrections welcome, especially from real scientists.

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I’m sure it is, but in no way can I express how: this’ll take some "sittin’ on the contemplation stool!"

My first conclusion was to avoid the softer PU in making sample IRS mounts to test, even if they give good values for static stiffness. Since I can’t make rubber parts I’ll work with the stiffer PU to develop the shape and size of the flexible bits.

Here’s one for that section of our fraternity who lie awake worrying about Ackermann angles. We know who we are… :shushing_face:

The latest version of RACE software includes a plot of Ackermann % vs steer angle. For the record, and to spread the excitement around, here it is for the standard suspension.


Some might choose to trust this more than my manual version from 2023, I’ll understand.

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DAMN!!

Busted, again…:blush:

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I looked up the meaning of these angles and appreciate why they are important but I don’t understand your graph Clive. So how does our standard setup compare to the ideal?