Hot rods to hell rear suspension?

[JohnUlaszek]

I for one would rather have a well sorted out rear suspension that I don't have to adjust.
You already have to worry about tire pressure, shocks, sway bars, weight balance, alignment, tire choice, etc. why compound the complexity with an "adjustable" rear suspension. Leaf springs and truck arms sourced from DSE or HTH are vastly improved over there OEM versions.
Sure a 4 or 3 link has sex appeal and you can surely brag it up on the net or to your buddies, but I am sure you could put Tucker or Pozzi in a leaf spring car and give me a new vette and Kyle or David would hand me my a$$ at the track.
Now if your car really is the limiting factor in your fun, you just have money to burn, or you're a twisted sob like John Parsons, go for it, just don't underestimate the amount of work, time, and money it will take before your actually going faster than the leaf spring guy. And at the end of the day you still have a solid axle with its inherent limitations.

[next69]

I have been thinking alot about the rear suspension of my upcoming 69 project, I think the fact that Kyle from DSE built his Twister Camaro and retained the leaf springs in the rear is priceless. This is a guy that would already have the dimensions of several completed designs in a filing cabinet, the ability to do it probably over a weekend, and he probably has all the parts to do it sitting in a bin on the back of a work bench. I am sure adjustability is crucial for a car that sees alot of track time, especially at different tracks but for a car that will see limited track time it makes no sense to pay all the money for something that will not be utilized on a regular basis.

[Ralph LoGrasso]

Chris,

I can't really provide a solid estimate on when it will be done and ready to be sold, sorry. I would say a few months from now, as an estimate. You could however, run leafs at first, even stock mono-leafs and continue on with the build, and then go back to the rear suspension. I will be doing my bodywork(not paint) before the rear suspension. The mini-tubs are done, and front suspension is getting started now.

[68protouring454]

guys, this may be a dumb question but in a 3 link are the coil overs, staggard or straight across?? like ralph said we could run leafs until its ready to be sold, but i will be welding my crossmember in and really do not want to do that twice, as that is the hardest part of the mini tub
jake

[dennis68]

Jeff, the 3-link is a far better way to go then the truck-arm. If you are going to fab your own suspension by all means use the 3-link, very good street suspension system.

[spanky the wondermuffin]

i agree the 3 link is a great choice-if you are doing your own fab work.it might be too pricey to have someone else design and build for you.

[JohnUlaszek]

Dennis68, thanks for the info on 3-links. Can you elaborate on your experience with a 3-link on the street? How do you feel it compares with your experiences with truck arm and leaf spring setups on the street? I looked on your webpage but I didn't see any pictures of your 3-link setup. Did you fabricate it yourself or did you use someone elses?

Thanks for the help

John

[dennis68]

Sure-I'll let you know as soon as I get it done. Got in over my head on projects and need to finish one at a time. I had the truck system on my 72 GMC (factory system). I added a tubular/adjustable PHB and monobal style arm bushings. It handled well and was VERY comfortable to drive. The system has virtually no adjustability though, not even close to what a 3-link is capable of. The other note about the HTH is that their kit includes rubber bushings in the forward link eye's, this builds bind into the design that doesn't need to be there. If I went this route again I would spherical bearings for sure. Tuning wise the truck arm is probably the most user friendly, there isn't any. RRCH is adjustable through the PHB mount but that’s about it, you can change pinion angle with shims. There is also the weight issue, the truck arms are much heavier than tubular links used in a 3-link/4-link arrangement. Ultimately the individuals call based on your monetary situation and ability to do your own fab work, I just the info out there as I see it from my research.

[dennis68]

Keep in mind Kyle didn't build "Twister" to be a corner burner, just a very well mannered street car. I really doubt that it would very competetive on a road course (not that it woyul dbe there anyways-too damn pretty to bang fenders), I see big time oversteer in that setup.

[JohnUlaszek]

Denny,
Can explain to us how you know that Kyle didn't intend the Twister to be a "Corner Burner"?
I wonder what he meant by calling the car the Twister?
Also, please explain why you think the Twister would have lots of oversteer?

John

[Norm Peterson]

Maybe we need to know what else the Mule required in order to fit up the 4-link that runs the asking price up that high; perhaps it's in regard to the upper link chassis attachments. In that regard, a centrally-located 3rd link should be easier to accommodate.

If you have an idea how much anti-squat you want, or some "not to exceed" number for anti-lift, developing a 3-link should be fairly straightforward. Even including the design of the crossmember that you'd need in an originally leaf-sprung car.

Once some collective experience is gained, aftermarket 3-links could become at least as popular as torque arms on Fox/SN95 Mustangs. Eventually, some generally accepted ranges of "anti's", spring/bar combinations, etc., will surface. I suspect that end-user adjustability is going to end up being mostly useful at the dragstrip, since a road course/auto-x setting would be fine for daily driving.

Norm

[68protouring454]

next, remember dse gave you an installed quote, ask hth for a quote i bet its near 5-6g with no rear end, gotta compare apples to apples, also for some middle of the road coil overs , and the rest of the links, etc how much can you put a 3 link together for??? as cheap as a 4 bar?? you can buy a 4 bar set up for around 800-1000 bucks, and install, maybe modifying the crossmemebers to work better in a camaro or whatever car you have, let me know
awesomer thread
jake

[dennis68]

I do not have hand first knowledge of Kyle's intent when he built the car, but based on the time and effort put into the rest of the car if it's intent was to be a truely competetive car in the autox arena I am quite certain he would not have intentionally left the Hotchkis style rear susepnsion in place. Anybody with skill and talent exhibited by the crew over at DSE could easily have put a 4-link/3-link in place with minimal effort and packaged in a way to save rear seating as done in "The Mule".

Leaf spring cars, regardless of spring rate selection or any other traction "helpers" , will always tend to oversteer in an autox enviornment. Compound that with extremly high horsepower and very non-compliant sidewalls and well, it would be fun to drive around the track, however loose is not fast.

[JohnUlaszek]

"I am quite certain he would not have intentionally left the Hotchkis style rear susepnsion in place."

I doubt Kyle built that car with the primary intent to autocross it, but I am quite sure he built it with the intent to run it on a road course as he had succesfully competed in the One Lap on numerous occasions in a leaf spring car.

When you start talking about being "truly competitive" in autox, what are you refering to? What class would a 4-linked first gen run in? If you want a competitive autocrosser, a stock miata would make a hell of a lot more sense than a highly modifed first gen if you actually want to compete in SCCA.

There is nothing "minimal" about the effort involved in installing a 3 or 4 link and saving the seats in a first gen. Smart design, engineering, fabrication and signifigant labor are involved if you really want to do it right.

Until someone starts selling a complete sorted out 3 or 4 link kit, leaf spring or truck arm kits are still the best option for most. Anyone can fabricate something that looks like 4 or 3 link, but there is a hell of a lot more involved than just making it look "right" John Parsons has had a team of engineers and fabricators help him get where he is at on IIMuch.

I would love to hear from those that have fully prepped DSE, HTH, or converted 3/4-links chime in and talk about their real world experiences.
Is anyone running the new Martz 4-link yet?

There is just way too much bench racing and measurebating at this point.

[dennis68]

[QUOTE=JohnUlaszek
Until someone starts selling a complete sorted out 3 or 4 link kit, leaf spring or truck arm kits are still the best option for most. .[/QUOTE]

Now that I am home and can think for a minute, not too long for fear of a headache. HTH charges 4K for the truck arm kit installed, this a good option? My felling is this, if you are willing to spend 4K for somebody else to install a different suspension system, obviously because you wish for your car to handle better (otherwise why do anything), you might as well spend another 1500 or so and have someone design and construct a 3/4 link. I just don't see spending that amount of money and not have the adjustability. I know the thought process is already going, why have adjustability. If you build it right the first time, you can just enjoy it. This is true, until 3-5 years down the road you decide to make a change, now you are stuck with a system that change with you. Truck arm systems are not the best thing going anyways, NASCAR uses them because they have to, Trans-Am (which I was a huge fan of) did not use truck arm or leaf, go figure. I was originally one HTH's biggest fans, I thought what a great system, I already had experience with it and it rides great. Then I started learning about the "other" options out there, and there are quite a few.
My take is if you are able to do your own work, you might as well build the best system you can, why stop halfway? If you are paying someone else do your work, you might as well pay the best up front. If you are satisfied with the way your stock designed suspension works then fine, leave it alone. I am not satisfied, I want the best. I want to jump in and take anything on the road at any event. Unreasonable, sure, but always aim high. I really enjoy the styling of the late 60's early 70's but can't stand the chassis/brakes. If you like running around with leafs-go ahead (BTW, have noticed that NO car produced anywhere today uses leaf springs, just an observation), I prefer something better.

[68protouring454]

dennis i agree with you about the 3/4 links being the way to go, but i believe the new vettes have leaf spring rear suspension, at least i think when i watched the c-6 on that british car show Top Gear they said it had rear suspension from the horse and carriage days, lol, it still went well but it did not handle like the gt-40, porshe's etc, they said its pure power made up for its cornering
jake

[Kenova]

OK. My head is starting to spin. So here is some more gas for the fire.

What about the torque arm suspension that is used on 3rd and 4th gen F-bodies? This setup seems to do well on both road courses and the strip. Granted it is usually modified to some extent, but seems to get the job done. It could probably be installed in a 1st gen F-body without doing any major surgery and there is plenty of after market support for it.
How would such a suspension stack up against the HTH and 3/4 links in terms of installation and versatillity?
Ken

[Norm Peterson]

Geoff - street-intended 3/4 links are a bit later to the game than truckarms. So until there's a bigger or at least more widely known base of experience with them, discussions concerning 3/4 links will tend to include more theory than installation details. We're still learning, and it's all in the interest of getting it right (or at least within tuning range) the first time. I'll bet that the NASCAR competition experience with truckarms simplified a few things engineering-wise, though.

I drive/auto-x a G-body, and I have driven a truckarm car at the RPDE out at Las Vegas. The RPDE car really was that easy to get into and drive fast, so items #4, #6, and #7 come as no surprise. Unfortunately, that driving experience didn't include any driving where the "anti's", unsprung weight, or "nimbleness" would have come into play (LV's turn 3/4 dip is a single low-frequency event that you don't hit hard enough to notice until the last 2 or 3 laps in a 1/2 day session assuming that you haven't frightened the lead car instructor), so all I have there is the theoretical considerations that tend to favor the 3-link.

. . . but i believe the new vettes have leaf spring rear suspension, at least i think when i watched the c-6 on that british car show Top Gear they said it had rear suspension from the horse and carriage days

Yes, the Corvette uses leaf springs. At both ends since the C4, actually. But unlike any "horse and carriage" arrangement, the Corvette leaf springs do not perform any geometric location function. That's left to the thoroughly modern control arm and multi link configurations. It appears that Top Gear's attempt to categorize the C6 as antiquity demonstrates either a lack of technical understanding, a dislike of front-engine performance cars, poor editing of the tape, or some combination of the above. I guess they were unaware that the quickest Corvette at any preparation level in the 2002 Solo II Nationals was a C5 that ran in Super Stock (its Stock class!), about 1.5 seconds quicker than the best 911. Or that currently, the SCCA's 'SS' class is little more than an official name for "Z06-spec class". TG is essentially a televised magazine, so treat it accordingly (try to separate the facts from the opinions).

Norm

[parsonsj]

John Parsons has had a team of engineers and fabricators help him get where he is at on II Much

Boy, isn't that the truth. Now that my front suspension is done, and we have ride height and tire clearance figured out, and we put an adjustable panhard below the axle centerline in, Katz and I are gonna tweak my rear geometry some to optimize anti-squat/lift.

So John is right about my 4 link setup: I sure didn't buy it and just weld it in. Well, I did, but it is requiring some tweaking to make it as good as it can be. Without support from real engineers, I'd have been lost. I'm sure once the car (and me) gets some lap times and autocross times, we'll tweak it some more.

jp

ps. What does "measureabating" mean?

[spanky the wondermuffin]

there is the problem.no testing.a comparison of leafs to anything else will only be valid if someone does a resonable job sorting a leaf spring rear on the race track then switches to something else and compares.i have had 4 front suspension setups on my car,with racetrack time on 3,and feel i might have a small bit of input regarding the front of a 1st gen. i guess until i try something out back we'll never know.i still have a couple weeks til my next track day if anyone wants to send me a truckarm kit,or any other kit, to be installed and tested.or just bring your car with non leaf rear out to t'hill in a couple weeks and we'll run them side by side.my son's new race car has a 4 link torsion bar setup so i'm about to learn something about that.