Sorry to start another thread on 308 suspension, but I've searched the archives and can't find all of the info I need. My car sits about 2 inches high at the front and I want to lower it. I don't have the funds to go and get adjustable coil over type set ups, and as I hardly ever track the car I'm quite happy with the feel and ride of the stock setup. What I'd like to know is what the compressed length of the front and rear spings should be on a 79 308gtb. Unladen springs should be 341mm and 376 mm front and rear respectivly. Before I take the springs and shocks off the car I'd like to measure their compessed lengths so I can have some idea of how far out my springs may be. Thanks
Tim I don't know for sure what measurement you want but I have my rear springs and new shocks on my bench. They are new Koni's and the length of the compressed rear springs mounted on the shocks and not on the car yet is 12 3/16". I'll let you convert to mm. I don't have the fronts off yet and I won't for sometime.
NO, the front springs are longer than the rear as standard, they are shorter once fitted to the shock though, as the front shocks are shorter. I've seen this mistake made MANY times, which results in your symptom of increased front ride height. Front springs are about 180lbs/" and rears are about 220 lbs/", but this varies across markets a little. What doesn't vary is the fact that REAR springs are both stronger and shorter than the FRONT, when loose and unmounted on the bench.
There are MANY threads about this in the Archives (use the SEARCH function). One thread is http://www.ferrarichat.com/discus/messages/256120/199158.html . The problem is if you just arbitrarily lower the car, you have no clue as to corner weight. Since you just cruise in the car, i presume at basic US legal speeds, it probably matters little about getting accurate weight anyway. As i recall, on the 308GTS it is 178 lbs front and 187 lbs rear. Seems wack having higher rated on the rear, but that is what it was. Verell posted a nice chart a year or so ago in another thread. You could get some custom springs made and that would do it for a basic driver. There was discussion about a perch that would lower the front. Again, check the archives as there is MUCH DATA to be found. Hope this helps. FYI: Because of tracking the car, i went with better, lighter, and adjustable shocks and uprated the springs. If you are just doing custom springs, perhaps uprate them a bit too while you are at it. i bet when you drive and hit the brakes hard the nose dips down brutally with those stock units.
Thanks for the info guys. I can't get at the job again till thursday, due to work committments. I'll start by checking out what you said Phil, about having the springs round the wrong way when I pull them from the shocks. I'll keep you posted.
It seems my springs are all over the place. All the shocks and springs were in the right place, but the none of the free lengths were correct, although 2 were about 5mm off being right for a gts. Both front and rear springs had the same number of tuns and the same wire diameter as well. I guess whoever was at it before me just threw whater he felt like at it. Looks like I've got a bit of archive reading time ahead of me to help make a decision or two. The shocks are in good working order. They've only done about 15000 kms, so I'm leaning towards just getting new slightly uprated springs made to go with the koni's. Anyone with any thoughts?
Keep in mind that your springs are old and have retained some "set", meaning that they're likely all compressed compared to the free length when new.
Mike, I realise that old springs will have 'set' a certain percentage, but to have the same number of coil turns and the same coil diameter when there is a 0.5mm difference is very wrong. It seems A$500 will get me a new set of springs made or I can get the right ones, used but correct and servicable, from the US for about A$400. I'd really love to get a fuuly upgraded adjustable setup, but my job's kinda on the line if the company outsources to China and I may need to prioritse my funds. Also, compared to my daily driver and all other cars I've owned, the stock 308 handling is a dream, so I'm sure I can wait a little longer without knowing what a 308 can really hande like. Although If I come to the USA on holiday sometime can I look you or Steve up to get a demo of the handlimg on your cars? Cheers!
Of course! If you find yourself in the northern New England area PM me here on Fchat. If you time your visit correctly we could go to an open track day so you can feel what proper conditions are like
Spring rates are just part of an equation that results in determining ride rate and roll rate at the wheel and not the spring, either in units of lb/in or better yet... frequency in Hz. A road car will always have a suspension ride frequency higher in the rear suspension than the front to avoid the platform from pitching over bumps and setting up an uncomfortable motion for the occupants. A car hits a pavement imperfection (of course) on the front axle first. There's a time delay between impact with the front suspension vs. the rear. Suspension spring/shock/wheel goes into bump (upward motion) first then rebound (downward motion of the wheel relative the chassis). The key is to get the suspension motions to influence the chassis into heave (the chassis remaining level to the ground as it moves up and down on the suspension) as opposed to pitch (the front and rear of the chassis moving up and down out of synch, like a boat on rough water) which in extremes will cause motion sickness. Race cars OTOH frequently violate this tenet of suspension design as they are optimized for roll rate as a priority over ride rate because time is made up in the corners and the driver must just deal with any discomfort on the straights. However, a well developed aero racecar will have higher suspension frequencies rear vs. front. Best, Rob Image Unavailable, Please Login
Absolutely! And from behind the wheel too if you think you can get used to driving on the "wrong" side of the road!
I sent my springs off yesterday for re-setting and should get them back tomorrow. Only A$140, so I thought I'd start with the cheap option first, before getting new springs all together. I'll see how I fare when I put it all back in place. Steve, Mike, thanks for the kind offers to look you guys up if I get over that way. I love coming to the States, I always seem to have a blast, and I get a little bit more comfortable driving on the wrong side of the road every time!
Tim where did you get a price for 4 new springs for $AUD400 and who is resetting your springs?Thanks in advance
Just want to say that I finally managed to get my car back together a fews days ago, and that having the springs reset to the factory specs has made a huge difference in the ride height of the car. It looks much nicer sitting those couple of inches lower at the front. I'm looking forward to going for a proper drive to see how different it feels. I can certainly notice the difference in the view from the drivers seat.
