| Author | Message | ||
| Ric Rainbolt (Ricrain)
Member Username: Ricrain Post Number: 319 Registered: 2-2002 |
$1500 for springs? Sounds a little high. I once priced a set of coil-overs for something like $1800 for my 308 ($400-450 per corner). It was for Koni adjustable shocks and 4" diameter spings, my choice of spring rates and lengths. I didn't go through with it at the time, but would seriously consider that for my 308 now. If you just want to lower the car, then use the lowering perches described elsewhere in this thread. | ||
| stu cordova (Balataboy)
Member Username: Balataboy Post Number: 320 Registered: 4-2001 |
Question; I've been looking at several options to lower my QV (just an inch or so - for cosmetic reasons only) and I was told this weekend that a local race shop could build me "custom" springs for about $1,500 installed. Any pros or cons on this idea? | ||
| Terry Limehouse (Terrykarr)
New member Username: Terrykarr Post Number: 20 Registered: 12-2002 |
When I asked the question initially I had just sent my car to Karl Troy to have some other work done [tune-up, oil change, oil leaks, etc.] and I haven't had a chance to look at it just yet. But I will keep you guys informed. | ||
| stu cordova (Balataboy)
Member Username: Balataboy Post Number: 318 Registered: 4-2001 |
Terry, any update on this project?? | ||
| Brian Liebler (Dino)
New member Username: Dino Post Number: 2 Registered: 12-2002 |
I have a set of 246 springs with about 50,000 mi. and about 30 years of sag. All four have been dyno tested and are sprung equally within 2lbs. They are 5 millimeters shorter than the new ones I installed.I can't tell how much the new raised my car because I also replaced all the suspension bushings. I can tell you on on fender height to ground it's well over one one inch higher now. I no longer bottom out with a passenger,the car rides and handles great but,it does appear a little high. When you look a some of the origional factory photo's you can really see how much room they allow for suspension travel.Before you do anything,take a look at your inner fender and see if your wheels are now rubbing.I have a feeling if you lower these cars too much,you'll have to make the spring and shock rate so stiff, it will no longer be streetable. I saved my used springs if your interested. | ||
| James Selevan (Jselevan)
Member Username: Jselevan Post Number: 270 Registered: 6-2002 |
Mark - my kids were discussing various things, and one asked me what the difference was between a mechanical engineer and civil engineer. I set them straight. "Mechanical engineers make weapons," I responded. "Civil engineers make targets." Jim S. | ||
| Mark Eberhardt (Me_k)
Junior Member Username: Me_k Post Number: 209 Registered: 5-2002 |
Jim, The Polish soccer team was flying to a tournament in Paris. The plane was is a holding pattern circling the city. The pilot announced that out the windows on the right the Eiffel tower was visible. With in moments the plane began to break apart and crashed. It seems that when the poles move to the right of center, the system will become completely unstable. That��s the worst math/engineering joke I know �� Terry, Nice vette. I had a ��65 coupe many years ago that I did similar things to. I always figure it��s mine and I��ll do as I please. Currently I please to figure out how to mount the Whipple AX2300 blower and water/air intercooler that I just bought to my 308. It should be capable of well over 600 HP. Last year was new springs and shocks, what a difference they made in handling and control. Good Luck with your project! | ||
| Edward G. Salla (350hpmondial)
Junior Member Username: 350hpmondial Post Number: 227 Registered: 2-2002 |
Mark & James, PLEASE Don't stop with the Engineering. I like all of that stuff too. (I got A's in Diff. Eq's) And I did appreciate the correction with Hook's law. But, I also like a guy like Terry. Who with patience, " Can make a silk purse out of cats a$$." Nice vette! And, I do remember a little about the 3D laplace transforms. But specific integration to change ones point of referance is "now" ,,, ,,,,, not one of my hobbies. (Question, would one use that method in space travel, nuclear physics or some other field. .. . . ?) Please advise, Now, on the Dino, is that another "Basket case" as your cool vette was? And, personally ,,, I like the rims. | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 338 Registered: 11-2002 |
Of course you could use that in a sales pitch, threaten to modify the Dino unless somebody gives you XXXX$$$$$$$$ by a certian date.....;-) | ||
| James Selevan (Jselevan)
Member Username: Jselevan Post Number: 268 Registered: 6-2002 |
Terry - my comments were a bit too harsh. Lowering the Dino is fine as long as handling and curb contact is maximized/minimized, respectively. My Dino is at the point that there is little tire suspension travel allowed before tire hitting metal. Jim S. | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 337 Registered: 11-2002 |
Terry, it's you're car, do what you want to it...make it fun for you. If the factory or the powers that be wanted every car 'their way' then they are obligated to keep them or buy them all back. But once they sell something, it's none of their freakin business what the next guy does. They sold all rights & claims. I put a V-12 in a 308 and was asked one time while out if I had permission from the Factory to change the car ! So do whatever lights your fire and don't worry about what others think. | ||
| Terry Limehouse (Terrykarr)
New member Username: Terrykarr Post Number: 13 Registered: 12-2002 |
Before to many of you start to go off on me, let me explain. When I bought the Vette it was a basket case and very little was original, which was the way I wanted it. The Dino, on the other hand, is pretty much original to the best of my, very little, knowledge. I would in no way, ever change anything on this car that couldn't be undone. I've been building and restoring cars since I was 18, I'm 47 now. Owning a ferrari is brand new to me, so you guys will probably be hearing alot from me. Don't take me to seriously, but believe one thing, I have the utmost respect for the automobile, especially the Ferrari. Thanks again for all your help. | ||
| Terry Limehouse (Terrykarr)
New member Username: Terrykarr Post Number: 12 Registered: 12-2002 |
If lowering bothers some of you, then this is really going to piss you off. I'm also going to add a set of 17" Kinesis to the Dino also....Sorry, but that's just me. Attached is a picture of the last car I built. Most people liked it and some didn't.  | ||
| James Selevan (Jselevan)
Member Username: Jselevan Post Number: 267 Registered: 6-2002 |
Mark - tonight it was Nyquist stability criteria and poles and zeros. They went right to sleep. Jim S. | ||
| James Selevan (Jselevan)
Member Username: Jselevan Post Number: 266 Registered: 6-2002 |
Mark - I give them the choice, "Do you want to learn about Laplace Transforms, or do you want to go to bed?" I'm one of those engineers that if you ask me what time it is, I tell you how to build a watch. Thanks for your help. As an aside, my Dino is so low, compared to the Boxer, TR, and C4, I am not sure why anyone would want to lower it more. I don't see this as a limiting factor. It breaks lose before rolling. Jim S. | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 332 Registered: 11-2002 |
>>>YAh,, Yah,,, yah,,,,, , , ,bla bla bla ... << Don't it just spoil all the fun of hackin stuff up when guys that did their homework come along and try to tell ya how to do it the right way. ;-) | ||
| Mark Eberhardt (Me_k)
Junior Member Username: Me_k Post Number: 208 Registered: 5-2002 |
If you want to run with the bigboys, you're going to need to learn to do some math or pay someone who did  | ||
| Edward G. Salla (350hpmondial)
Junior Member Username: 350hpmondial Post Number: 224 Registered: 2-2002 |
YAh,, Yah,,, yah,,,,, , , ,bla bla bla ... .. . Allright all you "Hooks Law" subscribers. Take the 246 springs off, have the things duplicated.. (They are old and sagging anyway.) Then chop off 1.5 coils,,, ,, add stiffer sway bars, ,,, then, check your roll center. Then track the car. If you want a concourse ferrari, then dont try this. If you want to run with the bigboys. .. ? "Try and try again." | ||
| Terry Limehouse (Terrykarr)
New member Username: Terrykarr Post Number: 11 Registered: 12-2002 |
Just wanted to let you guys know that I'm paying attention and that I really appreciate all the help. You have given me some really good ideas, and I will keep intouch with the results. | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 324 Registered: 11-2002 |
Great Thread....some of you guys really did your homework.....haven't seen anything mentioned about spring 'sag' though... | ||
| Steve Magnusson (91tr)
Intermediate Member Username: 91tr Post Number: 1227 Registered: 1-2001 |
Terry -- I had done a deeper lower front spring perch for my ex-308GTS circa 1990, and a group on the FerrariList did some more recent group fabs/buys as Tom J. mentioned. The part itself is shown on Stewart Chung's webstite: http://www.happyisgood.com/perch/index.htm and would work on any Koni that has the ~55+mm lower case diameter and uses the 5 mm diameter half-ring mounting design (I don't know 246s, but I've noted my TR front Konis are still the same design). The only minor complication is that you need to know the ratio from the suspension geometry for the "change in coachwork elevation" vs "the change in the depth of the perch". From the 308 WSM suspension drawings I guesstimated: at the front, a 1 mm change in the L1 dimension of the perch results in a 1.7 mm height change of the front coachwork (measured at the top of the front wheel arch), and at the rear (where the shock/spring axis is a bit more upright), a 1 mm change in the L1 dimension of the perch results in a 1.4 mm height change of the rear coachwork (measured at the top of the rear wheel arch). The quoted "drop" on the drawing only applies to the 308 front suspension, but I'd guess your 246 front and rear geometries are not that different (if you could use that lower perch design) so you can calculate the L1 dimensions you'd need for your particular situation. BUT -- This whole approach is based on being a simple reversible change at a lowish relative cost with minimal downtime (I paid my machinist friend $100 for the pair in 1990 and the recent group buys have been in the $200~$250 range for a pair). Recently Stu Cordova indicated that Truechoice had quoted him $55~$75 each for new shorter/stiffer springs for his 308 -- I'd definitely go that way if Truechoice can really supply the proper design at that cost with reasonable turnaround time. Stu -- what's the status? | ||
| Mark Eberhardt (Me_k)
Junior Member Username: Me_k Post Number: 206 Registered: 5-2002 |
Jim, Glad it helped. BTW, is that how you get the kids to go right to sleep? As is "don't make me come in there and tell you a bed time story". If they're really bad do they get laplace transforms? Mark | ||
| stu cordova (Balataboy)
Member Username: Balataboy Post Number: 311 Registered: 4-2001 |
Very good info on the subject below (thanks to Steve M. & Dave H., et al.) http://www.happyisgood.com/perch/quotes.htm | ||
| James Selevan (Jselevan)
Member Username: Jselevan Post Number: 265 Registered: 6-2002 |
Mark - "To teach is to learn twice." As I was explaining this concept to the kids, it struck me. You are correct. By shortening the spring one does increase the constant, which is the sum of all the parameters you mention. I was confusing this with the modulus of elasticity. Sorry. Jim S. | ||
| Mark Eberhardt (Me_k)
Junior Member Username: Me_k Post Number: 205 Registered: 5-2002 |
Jim, I should probably add that modulus of elasticity is a constant material property and it's basically the same for all steels, 30 Mpsi. It's stress/stain. A spring constant is force/strain and depends on the geometry of the spring. | ||
| Mark Eberhardt (Me_k)
Junior Member Username: Me_k Post Number: 204 Registered: 5-2002 |
Jim, X is the distance the spring is compressed or extended from rest. K is specific to the spring. It it a function material, wire cross section, diameter and number of coils. In this case the number of coils is being reduced. The result is that each remaining coil is moving further any X of the whole spring than before, so the spring apprears stiffer. The k for any one coil has not changed, but the k for the sum of the coils has. Clear as mud? | ||
| James Selevan (Jselevan)
Member Username: Jselevan Post Number: 264 Registered: 6-2002 |
Mark - I have done a bit of homework regarding your comment that shortening the spring increases the spring constant. Much of the discussion on the Web supports your statement. However, I believe there is a confusion of semantics and physics. The spring constant, as I was taught in my materials course, is a characteristic of the metal and curing process, and the geometry of how it is coiled. The force required to compress (or extend) a spring is described by F=k(x), where x is the displacement. By reducing the length of the spring, the displacement is increased, as you suggest, but the increase in force is a consequence of F=k(x) where x is larger, not a result of a change in k. K is constant. Thus, a longer spring will have an apparent smaller k, but this, again, is merely a consequence of less displacement of each coil, not a change in k. Help me here. Thanks. Jim S. | ||
| Mark Eberhardt (Me_k)
Junior Member Username: Me_k Post Number: 203 Registered: 5-2002 |
Cuting the spring actually does change the spring rate. There are less coils, so the remaining coils move more for every inch of travel increasing the spring rate, but not enough, the spring will probably be too soft to stop the car from bottoming. The simple calculation is that if you start with say 5" of travel and it is sitting mid stroke, you have 2.5 " of compression. If you lower it an inch, you're down to 1.5" of travel, so the new spring rate needs top be (2.5/1.5)x original spring rate. That will change the amount of preload you need a lot too. Cutting the spring also removes the ground end so the loads are not distributed around the spring and can lead to broken springs. I don't think I would cut the springs. The best way to do the job is with new shocks/springs which you can have made starting around $1000, I would go for the better shocks which will start around $2000 with springs. Away, you'll want to put the old shocks and check the suspension for bind see if you keep the stock travel, just lower the car or need to reduce the travel, that will have a big impact on what springs you want and how harsh the rid becomes. | ||
| Frank Parker (Parkerfe)
Intermediate Member Username: Parkerfe Post Number: 1590 Registered: 9-2001 |
Why would one want to ? The Dino is not what one would think of as a "lowrider" ! | ||
| Edward G. Salla (350hpmondial)
Junior Member Username: 350hpmondial Post Number: 223 Registered: 2-2002 |
Cut them 1.5 coils with a carbide saw. This way you will not change the spring rate. Add a set of thicker sway bars to complete the package. Remember to check & adjust your roll center when completed. | ||
| Terry Limehouse (Terrykarr)
New member Username: Terrykarr Post Number: 9 Registered: 12-2002 |
Thanks, I will look into that, maybe something I can do myself. | ||
| Tom Jones (Ferrarioldman)
New member Username: Ferrarioldman Post Number: 35 Registered: 6-2002 |
Somebody on the FerrariList made some lowering blocks for the springs for a 308. Should fit a Dino too. But I just don't remember who. Sorry. | ||
| Terry Limehouse (Terrykarr)
New member Username: Terrykarr Post Number: 7 Registered: 12-2002 |
Can anyone tell me if there is a coil over replacement available for the 246 that will lower the car approximately 1"? If not, is there any other way to lower it? |