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Re: JC whitney leaf springs |
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Moderator
Joined: 2001/5/3 7:04
From 48 North
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Well start a new Topic about it, see what happens. You may not get much response in this JC Whitney (cheap) topic.
Posted on: 2013/2/4 5:58
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Re: JC whitney leaf springs |
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No life (a.k.a. DattoMaster)
Joined: 2002/10/28 6:49
From under the Firmament LOL no twiglight effect BS
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The composites are the way to go, I had my leafs reset a while back with extra leaf for stiffer ride but cost me $360 when I was quoted 280 and the bastards just painted over the rust. $500-600 landed is a bargain since they are much lighter, dont suffer from axle tramp, better smoother response and never rust :) and only 150-200 more than steel. Grab a cup of tea and some cookies or a glass of wine and some nuts and enjoy this read. They went from the rare to find volvo single which ended up costing as much as the composites in the end. http://www.311s.org/phpBB3/viewtopic.php?t=10068Quote: After speaking to Lou Mondello about the experiences of various club members on tarmac rallies, I decided to try out something new on my roadster. First, the springs. Springs keep the bottom of your car from scraping along the road, and they also control body roll, both laterally and front to rear. Looking for some serious cornering ability, we fitted 15mm, 780lb springs to the front – about 50% stiffer than standard. These have worked well, with less diving under breaks and great turn in, but it’s the rear end that is the key to this car’s improvement. The rear springs have been replaced with single, tapered leafs from a Volvo 360. Single leafs have been used in rally cars for a long time, and DSRC member Horton Poulter’s ’67 Bluebird SSS was greatly improved with them. Weighing about half of a standard rear leaf, they locate the rear axle better than a traditional leaf (no slipping between springs). The Volvo springs, however, are stiffer than the standard Datsun springs – so if you’re going to do this, you do need to upgrade the fronts to balance the car. Step two for my car was shock absorbers. Like many here, I already had Koni shock absorbers in my roadster. However, the factory valving that Koni set for the Datsun roadsters seems to be much stiffer in the rears than in the fronts - which sets up that oversteer problem, and doesn’t control the heavier front end very well. So the valving was swapped, front to rear, essentially. So, the results. It’s hard, of course, to compare fairly between a sagged out suspension and new race setup, but fortunately I was able to drive a couple of other Datsun roadsters around the same time as we finished the changes on mine. The differences are instantly obvious. The new setup, very hard on the front and more compliant at the rear, makes the car much more willing to change direction. Quick left/right snatches (as through a chicane) are much faster, with less body roll and instant turn in. The rear end only comes out when provoked, and when it does, it does it with a lovely progressive feel. In short, the rear end is much more compliant, giving good traction even on bumpier roads. What surprised me, though, is how much nicer the ride has become from what it ever was. Bumps and uneven roads are handled with aplomb and railway crossings aren’t the terror that they used to be. All in all, an excellent result. Subjectively, at least. For more objective results, Alan Field’s car has since had similar changes made, and it seems to have had good results on the track. There's been a fair amount of input from many people and sources (Alistair, the handling guru in Queensland, Lou Mondello, a number of rally teams, and some good books, including Carol Smith's "Tune to Win"). I’d like to thank them all for the way that my car has turned out, and turns in!
Quote: In case anyone else is wondering, Yes, I do have my composite leaf springs installed. I'm running with the standard replacement KYB gas shocks and everything seems just fine, thankyou very much! I haven't done any racing or autocrossing, but in some mildly spirited driving I was very happy with both the ride and handling. Other than being a lot smoother riding than the old worn leaf springs there didn't seem to be much to talk about. Smooth, solid, and lighter. As far as the debate between composite and steel, I am firmly on the side of composite for at least a few reasons: 1) Safety - as much as some people seem squeamish about something as weak as fiberglass holding the a$$ end of your car up, everything I've read (on the internet no less) points to it being SAFER than the steel monoleaf. This is not a new technology. Corvettes have been using composite monoleaf springs since the mid '80s. There are many other vehicles which use/have used them from the factory. They are made for pickup trucks, 4x4s, all the way up to the big rig 18 wheelers....as well as in many forms of racing. If it's good enough for them, it's good enough for me. 2) Weight - Losing weight is good for both gas milage and acceleration. While Will may have a point as far as the wieght balance of the car, a few things I've pointed out before, such as moving the battery to the back, etc. can help the weight balance. On the other side, will you be racing or pushing your car to the limit? If not, even with everything else stock, I doubt you would notice anything other than the better ride in everyday driving. If you are racing, and need to add weight, you can corner weigh your car and put the weight where it will do the most good! Moving the battery from the engine bay to the parcel shelf/trunk WILL help balance the car, as will removing the stock 4/7 blade fan and shroud and installing a lighter electric fan, remove those heavy stock metal horns and put in a new LOUDER lighter plastic one.......... Remember Colin Chapman - "Adding power makes you faster on the straights. Subtracting weight makes you faster everywhere". ??Did I read somewhere that you want to eliminate as much unsprung weight as possible? And the leaf springs are counted as approx. 50/50 sprung/unsprung wieght?? 3) Ride height - With the eyes 'reversed' on the springs, my car sits pretty much level with the stock front springs. No lowering blocks required. 4) Choose your spring rate - Match the stock springs or go right up to 200+. I'm happy with the 180 lb rate on mine, but I'm no expert....... As far as the actual performance/handling/ride it's likely they are comparable, tho the composite is supposed to have an edge in reaction time, it's probably not noticeable to most people. To be fair, it's not easy to compare unless you've tried them both. So, like everything else on the car, this can be a game of compromises. Consider your options - newly manufactured stock style leaf springs (easy bolt in, what the car was made for), steel monoleaf (modified 28[?] yr old Volvo spring?), or made to order fiberglass composite leaf spring. Of course, I'm biased. I am not by any means trying to hurt anyones business. If it wasn't for Stephen bringing up the monoleaf dicussion, we wouldn't still be at it 28 pages later and trying to decide what is better. It probably should come down to the individual and what the use of the car is.
Posted on: 2013/2/4 6:39
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Re: JC whitney leaf springs |
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Moderator
Joined: 2001/5/3 7:04
From 48 North
Group:
Registered Users Contentmaster Usermaster
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Sounds like softer shocks was the key ...
Posted on: 2013/2/4 6:51
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Re: JC whitney leaf springs |
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Home away from home
Joined: 2010/3/7 10:22
From Brisbane
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Just had a look at the wiki for leaf springs looks like all 1200 springs are: 1110 mm long, 50mm wide. Bush sizes different?
Laden Camber * Sedan, Coupe: 11mm @ 192kg * Van: 11mm @ 295kg * Truck std 4-leaf: 18.5 mm/kg (589 in/pound) * Truck HD 5-leaf: 15.1 mm/kg (829 in/pound)
Did you ask what measurements are needed to make a set up?
Posted on: 2013/2/4 9:14
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Re: JC whitney leaf springs |
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Home away from home
Joined: 2003/4/8 14:53
From Brisbane
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The guy from flex form already has all the technical specifications. The reason I needed the length of all the leaves was that I was investigating a mob in China who make the conventional leaf springs probably quite cheaply and for less freight, but as to quality...might be best off ordering from NZ as they are cheaper than Aus, there's just the freight charge. email response from Chinese company below: Dear Mr Justin: Thanks for your interest in our leaf spring. We have checked the leaf spring, we could produce it . You offer us total 3 leaves,the thickness of 1 leaf is 6mm, the thickness of 2 leaves is 7mm, what about the width? And could you please offer us the length? It is better you have the drawing or detailed technical data. Then we could calculate the weiht ,and give you best price. Also this kind of leaf spring we have produced a lot which we export to Australia. We are waiting for your reply. Best regards Brittany Internaitonal Department Qingdao Shuaichao Group Web: www.shuaichao.comTel:008684915381 Mobile: 008615964253405
Posted on: 2013/2/4 22:32
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Re: JC whitney leaf springs |
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Home away from home
Joined: 2010/3/7 10:22
From Brisbane
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I have sent a message to mark flex form. Trying to find out ride height and what rates have been used before if any. Im really interested in buying some. Read that topic on 311.org all 28 pagers : )
Posted on: 2013/2/5 3:27
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Re: JC whitney leaf springs |
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Home away from home
Joined: 2010/11/4 10:45
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Registered Users
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I've also emailed mark asking about group buy prices. New thread to follow once I have a response.
Posted on: 2013/2/5 3:38
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Re: JC whitney leaf springs |
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Home away from home
Joined: 2010/3/7 10:22
From Brisbane
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Registered Users
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excellent should get the ball rolling
Posted on: 2013/2/5 3:41
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Re: JC whitney leaf springs |
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No life (a.k.a. DattoMaster)
Joined: 2002/10/28 6:49
From under the Firmament LOL no twiglight effect BS
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Registered Users
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all 28 pages! Brent you book worm!
Posted on: 2013/2/5 5:38
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_________________
"Australia" is formed by all its geographically listed territories "including" Norfolk, Christmas & Cocos Islands. The word include excludes all else before it therefore you have no legal rights.
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Re: JC whitney leaf springs |
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No life (a.k.a. DattoMaster)
Joined: 2005/8/27 15:36
From Townsville, Qld
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Just need to aoute this bit "67 bluebird sss". Why are they talking about mono leaves for a COILED rear end?
Posted on: 2013/2/5 7:34
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