I have lowered my F45 car as low as I could go with RK Sport kit and cuting the front bushing down. My problem is now the car's ride is horible. The car seems to be tring to compensate for the lowered suspension. Anybody know what I can do? I do not want to lose my ride control.

 

Get new springs, and you will be alright.

 

What springs do you think will work best?

 

hrm ... wierd. i have f45 and lowered mine 1.5". no problems with the ride - in fact, it is much better now. what setting do you keep f45 on? mine is always on performance.

 

Every damper has a " working range ". Within this range he moves during normal driving conditions. At both ends inside there are stopping rubbers for extreme driving conditions for example only one tire is lifted alone very high.
If you lower the car a lot, you move the dampers working range up against that upper rubber/stopper and then it gets harsh during normal driving.
IMO only a harder spring will solve this, but then the ride again is harsh. Just for explanation: If you lift the upper bracket of the damper exact the amount you lowered the car (and by this lifted the lower point of the damper), everything would be fine. But this is not a practical advice.
In short words: if you change the level of a car you will have to move the dampers too.
Frederik

 

I am sorry my first reply was not that detailed.
What C5 Fred is saying is true, there are some other issues that I did not like about lowering the F45 car. The first is when you lower the rear you are taking up all the travel on the spring. Thats why when you hit a bump it sucks, there is no absorbtion because the spring is already compressed so when it is tasked with performing most of the spring rate is gone. VB&P have the best springs and come in whatever spring rate you want. You can also go with Z51 or Z06 springs and keep your RTD performing, I disabled mine because the lowered cars work best with Bilstein, Penske, or Koni shocks. I know alot of people who have lowered their F45 cars with no reported problems.

 

When the car is lowered by only turning the bolts, the transverse fiberglass spring IS NOT LOADED MORE THAN BEFORE !! Who should load it? The weight of the car is constant. But the damper inside moves to the top and reaches the stopper on top earlier! And that makes it harsh.

One thing I do not know is the function of that hight sensor at the F45 damper. Does he compare difference between left and right or does he akt when car is going down (lowered)?

Frederik

 

Yes true (it is not loaded), I met to say it is not loaded. When you lower the stock rear spring it is being returned to its natural arc'ed state. So it is not loaded at all. When you tighten the bolts in the rear it pulls the spring up closer to the control arms and the force raises the car and consequently adds tension so there is more travel/absorbtion. The nice thing about VB&P's composite springs is that they are almost flat with no arc, they are completely different in there material. I have 850 lb spring and the only thing that has made my ride harsh is the T1 bars I installed...but I like the car that way. The Z51 and Z06 springs are alot stronger as well.


[Modified by Shinobi's97, 9:47 AM 4/26/2002]

 

Where do you get the VB&P springs? Also when is the suspension compressed to the limit. My car is sitting at 25 3/4'' front and 26'' in the rear. The strange part of my ride is that I have the suspension set to performance and the car has a lose bouncing feel to it. If I watch the rear wheel in the side mirror the suspension never seems to compress any more that what it is insted it seems to always travel upward.

 

Yeah thats a problem dude. Do a search for Vette Brakes and Product and it will come up with their website and info. They have any spring combo, talk to Paul he knows more about suspension than anybody else in the business....I mean I am sure this is why LPE uses him. Anyway good luck IM me or email me if you need help.

 

If you decide to get new springs it's best to trash or sell the shocks. I had the F-45 on my 98 and went through the same process. Lowered the Corvette and what a hirable ride. Changed the spring front and rear, better but not neutral. If you lower the F-45, first of all the shock will bottom out at high speeds on uneven roads, (if someone tells you they lowered their F-45 suspension and the handling was better I'm telling you they must drive like a Grandmother) not trying to **** people off but it's the truth, The stock spring rate with the F-45 shocks just cant handle the travel, you get this terrible bump steer. The only fix is to change to Bilstein shocks or another brand and Z-51 springs, are like they mentioned above Vette brake springs http://www.VBandP.com

I changed to the vette brake springs and Bilstein sports shocks and What an improvement. I will never go back to the F-45. After a friend drove my 98 ( he also owned a corvette lowered with the F-45) The very next day ordered shocks and springs. If you want to save $ give Mallet a call the web site is http://www.mallettecars.com they have take off springs from farley new corvettes and sell them for a good price, and go with the Bilstein Sports for about $260 a set of 4. :flag

Please read http://forums.corvetteforum.com/zerothread?id=287314

Good Price http://forums.corvetteforum.com/zerothread?id=282135


[Modified by 360Lemans, 8:38 PM 4/26/2002]


[Modified by 360Lemans, 8:41 PM 4/26/2002]


[Modified by 360Lemans, 8:45 PM 4/26/2002]

 

No and again no. If you are standing on a spring you will have a special hight of your head. if you take off your shoes (equal to turning the bolt) your head will come down. But the spring still has it´s original arc.
Frederik

 

Dude I am not going to keep arguing with you (C5 fred), I have had my springs off many times and I don't need the lecture. Take it off once and you will see. And don't tell me you need a spring compressor....I will go back to my original statement since this opened up into something else...you don't like the ride of the F45 or want better performance from a lowered car then get rid of those 450 lb springs and get some good ones. As it is just lowering the car changes the geometry, that is why there is an adapter being developed right now that will correct the geometry that an alignment can not. Good luck with your selection of springs. Call Paul he does alot of R&D on this stuff. If you have any further questions for me, send me a personal email, I will be happy to answer them. I did all my suspension work myself...everything! Including successfully deacitvating the F45 where others failed. C5 Fred if you plan on furthering this discussion please take off your rear spring first and see what he hell it actually does.

 

:cheers: Absolutly with you Shinobi's97: serious performance can only be done by changing both, springs and dampers. Both are responsible for the dynamic behaviour of the car

But :D :D
for all those guys (like me) who lower by just turning the bolts: in doing this NOTHING happens to the spring in meaning of preload or unload. I´m writing this as many on the forum think that the harsh ride after lowering results in a preloaded spring.

BTW: I change springs and dampers every day, but on mercedes test cars in our plant :yesnod:

Frederik