Friday night mathematics

I think now would be a good time to get my madness out into the open while i am still under the $100 experimental mark. i have a 91 Escort GT Rally car. it came with a sweet ass LEDA suspension that did not fit well and needed a complete rebuild. i found some rusty stock assemblies down the street and drove them to their prime. i had a set of front strut housings from a MK2 VW with much support for inserts i figured, why the hell not. initial measurements look promising so the cutting began. eventually (tonight) i start with this:
my measure base has been from top of upper knuckle bolt to upper spring seat. this pic represents similar ride height to factory equipment. please not these springs are 8" 350 lb rated. too short and too stiff.





Completely extended i now have 17" from top of spring seat to upper knuckle bolt.





compressed i have a distance of 10"






this leaves me with 7" of travel without bump stop, to play it safe i have kept 2" of bump stops to keep the skid plate off the ground by .5" on full compression. 7" total -2"bump =5 x2=10" spring length.


Here is the 10" mark from the unloaded ( in situ) strut scenario. Am i on the right track or too drunk to type this shit out?

Well since they aren't kermit ass green I'd say you have no mathematical chance of making them work.

they are not green, i was thinking 10" 275" lb springs with off the shelf Bilstein HD inserts. still too weak?

275 sounds about right. I think Hoche runs 250 in his Golf and I put 300 in the old Audi GT we had. Looks like you have room for 12 inch springs. Not knowing any better that's what I would get.

Where's JV when you need him??

You have to know the compression hieght of the springs you are getting, but 12" would be a safe bet. Also, my Escort GT rally car, I run metric springs, they are about 285in/lbs or so. If you run smoother roads, you can get away with 250 if need be.

-Jon

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jrally
You have to know the compression hieght of the springs you are getting, but 12" would be a safe bet. Also, my Escort GT rally car, I run metric springs, they are about 285in/lbs or so. If you run smoother roads, you can get away with 250 if need be.

-Jon

I thought i was close in spring rate however now my concern is lack travel. i got around to install these this weekend.
installed as is the ride height was increased by .5" i can attribute that to spring rate. my theoretical 5" travel is now 1.5" from strut top to bump stop... I plan to run NEFR and the like. i need more travel. i don't want to hack too much away from the stop and iam not sure what the old schoolers did but i cant justify the inverted bliss yet. i can pull em out cut the ears off. and set them a bit higher i can get maybe 1.5". my new measurement from upper bolt hole to top mount will change to 15.5 from there i will have 3" of compression travel before i hit the bumpers. good enough or should i throw the project away?

Sell LEDAs to some OtterCross perv. See what JV can do. Old School would be to buy lots of KYB GR-2s or Bilstein HDs.

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fiasco
Sell LEDAs to some OtterCross perv. See what JV can do. Old School would be to buy lots of KYB GR-2s or Bilstein HDs.

Those ledas found the dumpster a few weeks ago

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BJosephD

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jrally
You have to know the compression hieght of the springs you are getting, but 12" would be a safe bet. Also, my Escort GT rally car, I run metric springs, they are about 285in/lbs or so. If you run smoother roads, you can get away with 250 if need be.

-Jon

I thought i was close in spring rate however now my concern is lack travel. i got around to install these this weekend.
installed as is the ride height was increased by .5" i can attribute that to spring rate. my theoretical 5" travel is now 1.5" from strut top to bump stop... I plan to run NEFR and the like. i need more travel. i don't want to hack too much away from the stop and iam not sure what the old schoolers did but i cant justify the inverted bliss yet. i can pull em out cut the ears off. and set them a bit higher i can get maybe 1.5". my new measurement from upper bolt hole to top mount will change to 15.5 from there i will have 3" of compression travel before i hit the bumpers. good enough or should i throw the project away?

I always ran a heavier spring with Tokico ProDra shocks or KYBs. Some guys ran Bilstein. Normally the cars sat about 1.5 inches higher than stock using stock Datsun of Mazda housings. Thats pretty much what everyone did. No custom tubes or inserts.

But then again Gene, the stuff wasn't available to everybody.....and almost all the guys i was keeping going had double A arms and shocks..
Man I used to bitch about paying $65 for a gen-you-whine rally Bilstein or DeCarbon; imagine now getting 4 corners of struts of first class stuff for under $300.

Brian, just what kinda Ex-squirt do you have? Is it a real Frod or a Fraud-duh?
ya know I let almost everybody break up the cost of the stuff i make to spread out the pain. It is expensive but it bites less when it comes in 3-4 chunks.
Nudge-nudge, wink wink----know what I mean ? KNOW WHAT I MEAN? HmmmmmmmMMMMMM!! OOOOooooooo!

---

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.

Oh things is much better now. ProDras are long gone and we never had much travel anyway. Today the answer is ...your local JVAB dealer.

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john vanlandingham
Brian . . .
ya know I let almost everybody break up the cost of the stuff i make to spread out the pain. It is expensive but it bites less when it comes in 3-4 chunks.
Nudge-nudge, wink wink----know what I mean ? KNOW WHAT I MEAN? HmmmmmmmMMMMMM!! OOOOooooooo!

It's as if you were talking to me. Completely random, I ended up here tonight looking for more input on spring rates. I'm nowhere near ready for 'em, but I was reading through some old Gaylant homologation papers and got curious about spring rates and stabilizer bar sizes.

Must. Finish. Cage. Then. Order. Sooper. Bitchin'. Stuff... Do. Want.

---

Brian Driggs | KG7KCA | PHX, AZ | 89 Pajero
alterius non sit qui suus esse potest

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DR1665

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john vanlandingham
Brian . . .
ya know I let almost everybody break up the cost of the stuff i make to spread out the pain. It is expensive but it bites less when it comes in 3-4 chunks.
Nudge-nudge, wink wink----know what I mean ? KNOW WHAT I MEAN? HmmmmmmmMMMMMM!! OOOOooooooo!

It's as if you were talking to me. Completely random, I ended up here tonight looking for more input on spring rates. I'm nowhere near ready for 'em, but I was reading through some old Gaylant homologation papers and got curious about spring rates and stabilizer bar sizes.

Must. Finish. Cage. Then. Order. Sooper. Bitchin'. Stuff... Do. Want.

Those homologation papers online or real paper?
Love reading thru those.
I have Saab 96 Group 1, Group 2, Group 4, Group A (I had to get those, I was the last 96 in the History of the World Rally Championship and I built the car to gen-you-whine GpA spec.

I also have Ford Capri, and Opel Kadett E GSI 16v....the sheer volume of altrnate barkes mades my head spin but tell ya what: those papers are a gold mine of specific answers on sizings for all sorts of things like brake caliper piston sizes, pad size, clutch sizes, and simple info like rod c-c, comp hgt for piston, block height, journal sizes and GEAR RATIOS!

So you haz links?

---

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.

john i appreciate the offer to build me a set up. but this is my first rally car and $2k would put me back in terms of getting to the stages as soon as possible.the bigger money i plan to spend will be on the more universal rally specific parts. i bought the GT pre built and have all but roll cage update done yet. besides i would rather not be married to the escort platform by investing heavily into it. it would be a tough sell to move your used equipment after i prang the car. if i cooked up some measurements would you be able to stamp and drill some ears for me? here is the car as it sits




and a hay day shot for fun

Remember that the bump stop IS part of your total travel as it WILL compress to nearly nothing when you whack that rock, or stump, or ditch.... Therefore, your springs need to be long enough so that they do not bind before the bump stop is fully compressed. Therefore, 10" sprangs is too danged short.

I am sure JVL will make you just a set of fronts---the important end---just as he did for me back in 2003 and you can save some cash for now with some Bilsteins in back.

What is the weight of the car (front & rear if possible?)
I assume the fronts are struts like a VW so close to a 1:1 motion ratio. If the weight is similar to a Golf (i.e. about 2400lbs), I would run 225-250# sproings not 275-285#