Strut damage

OK very little time right now cause its first day of school and I have confrences and gotta get some VW stuff into UPS today and 0530 tomorrow, into the hospital again for rebuild on the 2 year old stainless knee.

Note to those people with warped minds and who see evil everywhere (and don't realise they see evil everywhere because that is what their head and heart is full of):
The following is intended soley to try and help the unfortunate bastids that have bought what I'll refer to as Brand X to salvage something of the more than 2400-2500 bucks americaine they spent and to let them have some fun.

OK. Anybody that has turned one of these Bilstein tops would see pretty damn quick that the raw pin is not real hard..
The inserts come with 22 x 110mm bar sticking out and we finish it to whatever we need ie Subie or VW or Ford Group A.

Now a lotta you guys know I almost obsess on trying to make this fool-proof or safe for you guys and the possibly sketchy or stressed out hired help you all have and I want things as easy as possible.
So knowing that the pins are not the hardest metal known to man, and knowing how people lose things and knowing that the Japanese evidently make up their own thread pitches once you get past 8mm, I would think it would be smrat to make the pins with what most of the world considers to be "normal" M12, which is M12 x 1.75.
Coarser is good with relatively softer material, and M12 x 1.75 nuts and Nyloc is dead easy to find--if you lose the one I supply..

Evidently, nobody at "Brand X" gave thought to this and they used some fine thread and it seems they didn't get the thread engagement full form since there's now a number of units with stripped to hell threads..

Now that's bad but worse id the general "design"..
Subies have a rear unit that is stock about 26.5" OAL with the D shaped top mount or about 25.5" with the triangled shaped ones.
Travel is just at 8.125" or 206mm.
So we must shoot for at least those 2 critical dimensions.
Here's OEM and Brand X:


Another view:


Note the length of the threaded portion...and the OAL of the lower tube--significantly shorter than the OEM tube...we'll return to that later.

As you can see, the Brand X is really a shit ton shorter than OEM.
Further there is only about 140-145mm available travel:


60-65mm less travel than stock....and that's when the unit is at full extention, unweighted...

the insert is set for 190mm travel not what it should be


So rather than 26.5" OAL the thing is maybe 22.5"
Rather than at least 206mm travel a 190mm insert was used and the assembled unit gives 140-145mm..

Here you can see the side by side difference in OAL


And while examining the design blunders:


No air vent holes---so you have an insanely progressive air spring at the insert compresses the air. Halve the volume and double the pressure. Halve it again, double that, halve it again double that...and on and on Very bad.

And we should just briefly mention that the valving chosen is a step of so lighter than I would want to see, while the springs were same as I expected.

Now for fixing these tragic errors first the pins can be redone shorter--there was enough room to make them like OEM and JVAB pins without the long extended shoulder you might notice--an effort to make the OAL longer.

As for the tubes, the fronts might be OK, I haven't had some in my hands to see if that was somehow gotten right.
The rears are not useful, they're just too short and using a spring long enough to not coil bind with correct inserts means the threads don't extend low enough..
Solution: For sure new rear tubes, inserts revalved and limiting spacers removed. new rear springs
Fronts, can't say how much can be salvaged. They are also valved softed both ways than I'd like to see but maybe you guys can fake it.

You can end up with something at exceeds the OEM thing, not is shorter by several inches.


I have to run. More I'm sure later.

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Very interesting.

Plate used on brand x looks thicker. Is there a reason you don't use that thick of plate for the mounting tabs John?

Is Brand X like New Coke or Crystal Pepsi?

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FunctionAuto
Plate used on brand x looks thicker. Is there a reason you don't use that thick of plate for the mounting tabs John?

Yeah. Formability. And like most things I do, from "praxis", previous practice... which means i looked at the stuff on some WRC car and they used a smidge thinner, so I step it up for us ordinary clubbie schmucks

Now you notice that I bend mine and hat flare out means it is a form of gusset and bending force--->. that away is resolved differently than welding the thing sticking perpendicularly out of the tube..
I visualize a plate with no gusseting as kinda like having a "hinge"

(remember, I spent the first half of my life living on moto-cross bikes in a period of extremely fast development is suspension, going from roughly 150mm travel in front and 100mm in the back in say end of 1972 to 200mm by '74 and 250mm by 76 and fully 300mm by 1977. Enormous changes in suspension meant huge revisions of the frames of the bikes..

Now we were extremely weight conscious and we're stressing things far far far more with each step up, so we, I, got to see living in You're-up and sharing garage and track with actual World Championship top type guys, i got to see all kinds of, all brands factory bikes---and we'd whip out the hacksaw and carve up frames and swing arms and mounts--and take apart dampers---within a few months of designs appearing on GP bikes....
So we got to see specifics of how the Euro Works bikes AND the mega-million Japanese works bike solved strengthening problems.. Like what worked and was "season long" reliable and what was not quite enough to do 2 full GPs---and then see the next years productionised versions of the previous seasons development..
It was a better education than one could ever get in any classroom.
So gusseting a 3/16" plate sticking out is flat way better and doesn't NEED TO Be 1/4"..

And where there is a proven geometry problem like the rears of the Subies with the strut placed in front of the spindle and doing a sharper arc than traced by the hub, I've gone to Chrome Moly 3/16"---and that's at the limit of what I can form with the tool and die I made and my hydraulic press.

Claro, muchachito?

Faaaaaaawk I'm still way high but fawk me the knees throbbing. Where's my Rush Limbaugh Skittles?

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.



Edited 1 time(s). Last edit at 09/05/2012 10:01AM by john vanlandingham.

Question, I'm looking at the tube threading of Brand-X and yours and I see that Brand-X stops much higher. Could the reason their overall length is shorter is because the tube threads don't go down as far and therefore gives the same "stock" ride height? Based on the rust on the threads of Brand-X it looks like the hieght was kept higher then where yours would land on mine.

Here's as low as I was able to take my rears before the spring was unloaded and able to move around (without helper springs). It sits at the stock height and can can't go lower without the spring moving.

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R.Sealey
http://www.facebook.com/SealeySport
http://www.youtube.com/ryolse



Edited 1 time(s). Last edit at 09/04/2012 02:33PM by ryolse.

Shorter area of threads means you'd have to use a shorter spring. Assuming you were both on the same spring rates and cars weighed the same, you're going to have the same amount of compression when sitting still whether you started with a 12" or 14" spring.

Where longer springs are beneficial is that you have more compressible length before coil bind. Also note that with many springs, as you approach coil bind, the stated spring rates may change a bit. Swift Spring for example does a nice job of listing spring rates, lengths, compressible length, and compressible length before coil bind (http://www.swiftsprings.com/file/metric.pdf)

I played around with various setups on the rear of the BMW. I ended up swapping to some high travel 14" springs (different steel used so the steel itself is thinner) of a slightly stiffer rate (200 vs. 175) and did some playing around with foam bumpstops too. Doing that allowed me to get rid of the helper setup I started out with...so I figure in rally, more parts to break is more parts to break.

And one final question - why are you running at stock ride height? Its a rally car isn't it?

Dave

While I do get the first 2 parts. I don't understand why I would want more body role as a result of lifting the car when I haven't had any clearance issues so far(?).

---

R.Sealey
http://www.facebook.com/SealeySport
http://www.youtube.com/ryolse

Quote
DaveK
Shorter area of threads means you'd have to use a shorter spring. Assuming you were both on the same spring rates and cars weighed the same, you're going to have the same amount of compression when sitting still whether you started with a 12" or 14" spring.

Where longer springs are beneficial is that you have more compressible length before coil bind. Also note that with many springs, as you approach coil bind, the stated spring rates may change a bit. Swift Spring for example does a nice job of listing spring rates, lengths, compressible length, and compressible length before coil bind (http://www.swiftsprings.com/file/metric.pdf)

I played around with various setups on the rear of the BMW. I ended up swapping to some high travel 14" springs (different steel used so the steel itself is thinner) of a slightly stiffer rate (200 vs. 175) and did some playing around with foam bumpstops too. Doing that allowed me to get rid of the helper setup I started out with...so I figure in rally, more parts to break is more parts to break.

And one final question - why are you running at stock ride height? Its a rally car isn't it?

Dave

Just a little note: the bend modulous is the same for all ferrous metals.
Cast iron or silicone chrome vanadium steel, same bend with same force. The difference is in the fatigue resistance. Iron, bend it once and maybe it cracks. 1021 Steel maybe it bends a few times and takes a set, a few more times and cracks begin to appear. Use some sooooper bitchin alloy---like valve springs, cycle it 100,000,000 times and its still happy.

The longer travel springs with thinner wire have less total wire, unwind it and maybe there's say 5 feet of .440" wire, the next maybe 16 feet of .5 wire. Fix both in an imaginary vise sticking out horisontally unwound and place a standard weight say 100 lbs on the end and its clear that the shorter bar is stiffer..
Even easier to imagine is same wire say .5" 6" long vs .5" 20 feet long, same wire, same weight and that 20 footer is going to deflect a lot, and the 6" stubbie thang maybe 020" deflection..

Clear as mud?

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Quote
DaveK
And one final question - why are you running at stock ride height? Its a rally car isn't it?

Dave

Quote
ryolse
While I do get the first 2 parts. I don't understand why I would want more body role as a result of lifting the car when I haven't had any clearance issues so far(?).

Subaru's have a decent amount of clearance stock, so stock height or just above isn't a big deal. For those of us running non cookie cutter rally cars, an increase in height is mandatory to keep the car from smashing things with the bottom.

That being said, if I was running a Urabus, I would run an inch or so above stock at least. Even running closer then most to the pointy end of the stick, I still see my fair share of baby heads, and sump slaughterers.

You may not have issue with clearance at curb height, but load that thing off a yump or dip, and you can run out of space under the car in a hurry. I like a little extra since Im not skilled enough to make use of every last iota of cornering grip available to me anyway.

---

I Seppanen, Car #240



Edited 1 time(s). Last edit at 09/04/2012 10:14PM by Ian S.

Just got off the phone with John (who is drilling the holes in the ears for my struts) and he said "huh?" Ryan.

But as far as ride height and clearance go, I think the operative phrase there is "so far." everything I experienced in Colorado and Idaho I can see your point as its all pretty smooth but it's nice to have the option/ability for some of the rougher events I have only read/heard about like Gorman or the one roger went to that he described as out in a field. Rougher events I would assume are slower and body roll is less of a concern anyway. Besides body roll isn't a bad thing on a gravel car is it? Transferring the weight is how you get traction on a loose surface.

Yeah, I don't have any swaybars, and like it that way.

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ryolse
While I do get the first 2 parts. I don't understand why I would want more body role as a result of lifting the car when I haven't had any clearance issues so far(?).

A little more body roll is good because you can transfer weight around with your feet and the wheel to help aid traction. Remember on dirt the extra bit of roll gives the tire a better chance to take a set against the ground. If no body roll was good, John would be shipping out the kits with 500# springs instead of 200ish, and those of us trying to do double duty with our cars would be able to simply have one suspension setup...ooo, how that would be nice. For reference, the Evo's Ohlins gravel suspension runs about 225#F&R while the tarmac setup with minimal lean is ~615#F/~840#R.

Lets work up a quick scenario, but remember these first two bits of info (if they're true, LOL):

You've only beat up on the car at CORE, a place known for having zero rocks.
You've only railed on the car at CORE, which is at 5000 foot elevations.
I think you said you were able to reach ~60mph before getting airborne.

Imagine yourself at sea-level with 20% more power. The car will squat harder on acceleration and reach higher speeds. Now think about taking off a jump at those higher speeds and landing with both tires in ruts that are 1" deep...2" deep...or on flat ground with a rock that sticks up off the road surface 1"...etc. Extra ground clearance is nice to have in those circumstances.

Dave

True, true and true. At the end of last year I tried it without the rear sway on stock dampers/springs, and the dampers were pretty much there to hold the springs in place because they pulled in and out like a trombone. With that "setup" the thing felt like a death trap, so I put in a 22mm rear sway instead of the stock 14mm. That helped it a little from going all over the place. Sunday morning I pulled the 22mm rear sway off, and that helped a lot in getting the rear to kick out when I went out to CORE.

And I agree that it’ll likely go up in height as you were saying, but that will happen once the thing finally does see some actual hill climbs and stage miles. I remember when doing Advanced at COG in ’09 one of the first (if not the first) stage was really rough and rocky, and that’s coming from someone who grew up living on old mining roads in Clear Creek County. And one of the other early stages on Sunday there were ruts so deep that the car was getting pushed up on if didn’t stay out of them.

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FunctionAuto
Just got off the phone with John (who is drilling the holes in the ears for my struts) and he said "huh?" Ryan.

¿Qué

---

R.Sealey
http://www.facebook.com/SealeySport
http://www.youtube.com/ryolse

Quote
FunctionAuto
I can see your point as its all pretty smooth but it's nice to have the option/ability for some of the rougher events I have only read/heard about like Gorman or the one roger went to that he described as out in a field.

I'm always happy to tell people which events NOT to do. I've never understood with how expensive rallying is and when most only do one or two events per year why people would pay to do events that aren't the best rally to do.
The field one was in Texas.
From Casper, Kananaskis, Big White, and other Alberta based events should also be on your radar. I can think of nine events that are similar distance that I would do BEFORE towing out for Gorman.

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Grant Hughes