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mws
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Posts posted by mws
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Exactly. Ford/Dodge would need to invest engineering time and cough up a CONSIDERABLE amount in tooling to build a better front suspension. So they haven't. With Ford and GM's financial situations, they probably won't/can't. Although GM probably could save quite a bit by borrowing some parts from the H1.
WHEN Daimler does, it will be yet another nail in their coffins. Of course, Daimler will have to offer both IFS and SA versions for a while to pacify the techno-phobes in the market, but within a few years, the demand for the old stuff will die away. That's the way it works with mass marketed technology.
The SA/IS argument is almost identical to flathead/OH valve deal of the 30's. Or the drum/disk brake deal of the 60's. Or the carburetor/FI deal of the 80's. Or the OHV/OHC cam deal of the 80's. Or the no air bag/air bag deal of the 90's. Or the manual/anti-lock brake deal of the 90's. Some automakers eagerly embrace better technology, some resist. Once they embrace the technology and start mass producing it, the costs plummet. 10 years later, the prices and technology finally become accessible to the home mechanic. What once was considered too expensive and "not needed" eventually becomes the norm.
I agree COMPLETELY that a SAS is much easier and far less expensive than a hi-lift long travel IFS today. But I urge you to not confuse that with "better". You gain some things, but lose others. They are a compromise and you should know that and be prepared to accept what you'll lose. Kinda like my Frankenvan. In choosing to make a full size van into our tow monster of choice, I need to accept the compromises. Mainly, difficulty in finding the ideal parts, need to modify so freaking much, and lack of any resale value whatsoever. But I knew this going in and and accept it.
I encourage everyone to do what they want, but do it wisely!
In Bernard's case, he is - much like I expected
. I jumped in 'cause I saw a chance for some meangful dialogue on the pluses and minuses to a SAS for anyone eles considering it. to I look forward to following the progress of his project. -
Throwing another handful of mud into the soup... and then hopefully some clarifying medium....
I have a pair of front springs out of a 4.0L (I6) Jeep something sitting in front of me (thanks, Red!).
They have just under 8.5 coils, but it appears Red already cut the pig tail off.
The springs are just over 17" long.
The wire is .54 to .55 inches in diameter
OD of spring is about 5.25", ID is about 4.00"
I will be installing these in a month or two and will report what lift (if any) they provide.
In a previous life, I worked for NUMMI where we produced Toyota Corollas and Geo Prizms (same car, different cosmetics). There were at least 10 different models of front springs used for this "1" car depending on options and trim levels. DX, LE, GXI, LXI, with A/C, without A/C, etc. And that was just for the model year in production - there were some year to year changes as well. Only 2 versions of rear spring as I recall.
So it is very likely (and looking pretty sure) Jeep used more than two different front springs over the years. They were probably not as anal about providing "optimal" suspension as Toyota was, but as our data base builds here, it appears they did offer some variations.
And the aftermarket companies will not want the hassle of stocking all these varieties, so they are going to offer only a "universal" or "one size fits all" variant.
So my suggestion is that we're going to have to start measuring and reporting more information to provide more accurate predictions of results. The wire diameter, number of coils, and static length (without pigtail) will all affect the amount of lift that will result. And heres how each will affect:
Wire diameter: Directly affects spring rate, or how much the spring will compress under a given load. Spring rate changes as the square of the change in diameter (eg, doubling diameter quadruples spring rate). The larger the diameter, the stiffer it will be. All other things being equal, the larger diameter wire will provide more static lift as it will compress less under the weight of the vehicle. It will also provide a stiffer ride as it will compress less under the dynamic load induced by a bump.
EDIT: DOHHH! The spring rate increases much more than that - it increases at the rate of diameter change to the 4th power!. So doubling the diameter gives 16x the spring rate! Going from .52" to .56" gives, umm, something like 35% increase in spring rate. That's a bunch.
Number of coils: Directly affects spring rate as a linear function. The more coils, the lower the spring rate. This only applies to coils that are NOT in contact with each other.
Static length: Obviously, a longer spring will provide more lift. ASSUMING the wire diameter and number of coils is EXACTLY the same. Most folks are surprised to discover this is probably the LEAST important factor. A very long spring with lots of coils of smaller diameter wire will compress a lot under the static load of the weight of the car, and will end up lowering it. A shorter spring with thicker wire and fewer coils will lift it.
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That got me literally laughing out loud!
I am soooooo a redneck in so many ways....
And I have cursed many a previous owner...
And I have actually uttered those immortal words... Well, maybe not the Ya'all part...
If you want some heatshrink, PM me your address. I have some to spare.
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:bow: :cool2: Good on you! Now I am REALLY impressed!
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First off, to answer the question: 4 will be fine 99.999% of the time - assuming the 4 have not been excessively weakened by overtorquing or damage. It 's the .0001% of the time when you have to make an emergency evasive manuever that it will bite you. 3 would even be fine IF (and only if) they were in an undamaged condition and evenly distributed. A safety factor of 2 would be the minimum for a critical fastener like that.
After that, I have to put on my engineer hat and say they should never, ever strip. Take care of them - they are critical!
* Always use a torque wrench. Never exceed maximum torque. Doing so is what causes most failures - overtorquing stretches the bolt, weakening it and distorting threads. Overtorque it once, and it is screwed forever. Period.
* Never let garage monkeys use impact wrench to install! Do it yourself. Insist on doing it yourself.
* If the bolt will not spin on freely, STOP! If the threads on the stud are damaged, chase them. If the nut is damage, replace it.
Never had one loosen, strip, or fail since I started doing these things about 20 years ago.
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Nicely done!
But I have to issue a mild hiss at using a cell phone in the car. I am one of those that believe the stats that show drivers using cell phones are more likely to cause accidents than even legally drunk drivers.
Although I like to consider myself better than average (don't we all?), I still choose to avoid distractions and will not use a cell phone while driving. I have never caused a crash (25 years +) and actively try to keep it that way. When I was a teenager, I had a friend make a simple mistake that ended up killing a lady. Who had young children. It impacted her every bit as much as you could imagine. Had to drop out of college, broke up her engagement, pretty well f-ed her up mentally for decades. Seeing that left an impression on me as well because I take responsiblity for my mistakes. I would hate to have to live with that so I take operating a car pretty seriously.
And then 12 years ago an employee at my company crossed the center line and killed a motorcyclist because he was reaching for a cassette under the seat. F-ed his life up as well - legally and mentally.
In retrospect, I have not even been in a crash for about 25 years... And that one was someone rear-ending me at a red light. That got me learning and practicing defensive driving.
* steps down from soap box *
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wouldnt want that sucker inside the car in an accident. i would hate to think would it could do.
Yup, if you mount it inside, secure the dickens out of it!
I'm planning to add a cable "tether" as a final safety measure. Think F1 wheel restraint... The existing brackets will withstand a couple dozen G's, but in a severe head on (100G+), they would come loose. Well, actually the failure mode would be the jack ripping the subwoofer box apart (only 3/4" MDF).
I just need to figure out where to secure it to the body.
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I can relate. So many projects...
Something I am finding myself do more often: Hand over the projects to younger folks I respect and help them learn what I have learned. Call me a sponsor or a mentor, or whatever. My nephew's youngest is a common recipient.
No financial reward, but good feelings galore.
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Being the AR enginerd, I will be cutting into the stock wires and soldering the connections in.
My 25 years experience of doing custom vehicle wiring (stereos, alarms, etc) have given me the following opinions of termination types:
The number is how many connections caused problems over the next 10 years or so of service (usually intermittents that cropped up in cold or wet conditions):
Quality solder joint with heatshrink insulation: 0% problems (This is based on several thousand terminations. I have never had a failure. I am IPC trained and certified)
High quality connectors with gold plated contacts soldered to wires: 0% problems
(Amp Multi-Mate II connectors - expensive, but excellent. Probably 1 or 2000 I did at home, a couple hundred thousand at work building mainframe computer wiring harnesses for IBM - 0 reported failures)
Connectors with tin plated contacts soldered to wires: 0.5% problems
(Standard Amp Multimate style, have had some issues when exposed to elements)
High quality crimp connectors with high quality crimps (3M or Amp contacts with commercial crimp tools): 0.5% problems
Average connectors with home style plier style crimps: 1-2% problems
Quality IDC T-tap style connections or wire splice: 5% problems - usually 1 or 2 years after install. Quit using them, even had intermittents with 3M versions.
El Cheapo Taiwanese style splice or T-type connections: 10%+
Never use them anymore....
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THIS POST IS USELESS WITHOUT WORDS!
hee-hee.... couldn't resist.
Probably shoulda...
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I have been getting about 180 for years with stock 31s. I also think my 89 has a 19 gallon tank as well as I ran out a while back and it only took about 19 to fill it.. do the multiport motors get better mileage than us tbi motors?
Theoretically, they should. But based on the postings in this thread, it is far less a significant factor than tire size, tune up condition, and driving style.
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We almost never use the rear seat, so I made some heck for stout brackets that mount to the top of the subwoofer enclosure (which is bolted to the floor) on the right side of the cargo area. The jack is positioned fore and aft about 2" away from the passenger side window, just above the top edge of the rear seat. Actually, a passenger can still sit there, but the jack is right by their right bicep/shoulder.
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great information! Thanks!
We call it "pencil CAD"
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The old wisened mechanics method:
Clean up everything really well with a couple cans of electrical cleaner. Sure it costs a few bucks per can, but it works extremely well to cut anything and is not as harsh on plastic or rubber parts as carb or brake cleaner would be.
Get a can of aerosol foot powder. That's right, aerosol foot powder. Talc in a paint bomb.
Spray liberally over the side of the engine where you think the leak could be originating. Looks like a pretty christmas scene now, doesn't it?
Start it up and watch. The second even a micro drop of oil oozes out from its source, your nice christmas scene will have a grotesque and impossible to miss splotch of black goo!
That's the source. Now let it cool down, hose off the talc with water and fix away!
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Not yet.. but gonna have to check it out! Got any links?
Last key to the ultimate crawler: NO driveshafts or differentials.
Can you say hydraulic drive? With computerized traction control? Thought you could...
And then, just for giggles, how about a little 50 pound turbine engine screaming at 120K rpm or so to power the hydraulic pump? That should cause the Heep boys to drop a deposit in their shorts, ehh?
Or is that going too far?
Whoa.... Sorry I took your thread so far off track, B. Feel free to move stuff as appropriate.
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Ohhhhh, yes. Infinitely more comfortable!
Not only is the basic design much more comfortable, and with more padding and nicer upholstery, the ones I got have knob manual adjusters for fore/aft, recliner, seat height, base angle, and lumbar support.
Honestly, they are more comfortable than our BMW!
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Interesting read MWS -- But with a SAS properly aligned and assuming B rotates his tires (
) How much of a shorter life are we looking at on set of tires?And B -- Your long term plan doesn't have the pathy as a daily driver does it? I remeber you saying something about moving closer to work so you could take the cabrio on a day to day basis.
Good questions. The answer is: It depends!
As you can imagine, it all depends on how often you need to turn, and how hard you're cornering.
On an 18 wheeler cruising freeways, probably less than a percent or two reduction in life.
If you drive curvy roads in a spirited way, cutting tread life in half (or even more extreme) would be quite easy to do.
But if almost all cornering is in low traction conditions (dirt, snow, etc), it reduces wear.
So depending on what you want, the trade offs may be insignificant. My goal is to educate everyone to allow them to make good decisions for themselves.
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I have this fantasy of building a fully independent rock crawler with about 24" to 36" of travel and active suspension at all four corners.... I have the concept pretty well flushed out in my mind.
Although it would be outrageously complex to engineer and rather expensive to build, it would absolutely re-define the activity and blow everything else away.
The down side is that it would require all rock crawlers to follow suit to be competitive, which would mean anybody with less than a few hundred thousand dollars or their own engineers and machine shop would not be able to compete, potentially killing the sport.
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I can understand the difference in ride MWS but reduced tire life? Seems to me if he gets all the suspension geometries correct and everything is properly aligned tire life shouldn't be too different. :confused:
By design, solid axles (SA) will not allow much, if any, variable camber during cornering, and variation of toe in is not as accurate. Properly designed independent suspensions (IS) allow more accurate variations in camber, caster, and toe in during cornering - which reduces tire dragging in corners.
What you want during cornering is to have the camber increase on the outer wheel (top lean in) to compensate for the side loading and tire carcass deflection so the load is distributed across the entire tread. And you want the inner tire to actually turn sharper than the outer tire (increase toe OUT) since it needs to travel in a smaller radius circle.
When going around corners with a SA front, the outer tire overloads the outside edge of the tread blocks (due to insufficient camber) while the inner tread blocks of the inner tire gets scuffed along (less than optimal variable toe when turning).
Not much of much of a problem off road or when driving in relatively straight line, but if you look at the front tires on any front SA'd vehicle driven regularly on aspalt, the inner and outer edges of the front tires wear away faster than on a comparable IFS using the same tire. And the more turns taken, the more extreme the difference. Ford's twin I beam is a little better, but still inferior to IS.
That's why they are completely obsolete on anything but:
- 4x4's with cost constraints. Making a long travel IS is expensive (see H1) and/or very wide (again, see H1)
- Long haul trucks (18 wheelers) that don't corner much or very hard.
- The rear of some automobiles. Again, only because they are cheaper to build and the manufacturers are hoping consumers are willing to accept inferior products to save a few bucks.
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Perfect! Thanks!
(And I'm glad it's the left side - it doesn't require pulling out the subwoofer to get to!)
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You are keeping in mind the SAS will compromise your ride and tire life, right? Or maybe not, depending how screwed up your front end is now...
But being the engineer, I feel an onus to let people in on all the facts.
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BTW, I picked up a set of good condition Maxima seats for $50 from a JY. Some work with an upholstery cleaner and they look (and feel) brand new.
Yes, took some creative work to mount them, but it's doable.
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I need to wire my '87 Pathy for towing a trailer.
Is there a convenient spot to access all the necessary wires in the factory wiring harness? In many vehicles, the running, stop, left turn and right turn wires are all together on one side or the other.
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And as for tires, I can not begin to overstate how superior severe service traction tires are over standard or all terain/ M&S tires.
SAS with Calmini's help, and yours
in The Garage
Posted · Edited by mws
Oh, and B, depending on how much you're willing to drive, we could do pretty much all of the work at my place! Between your machining skills and knowledge, my engineering knowledge, and our combined tool selection and experience, oh my.
I've been thinking about a project to pursue after Frankenvan....
Depending on the costs, I'd also lean heavily towards a coil spring version over leafs. Coils just give you a lot more flexibility in geometries and spring rates. If you design it to use Jeep sized coils, you have the ability to change spring rates and ride heights for very little $ or time.