[V8] Lowering thought

[qshipq at aol.com]

 Been on these lists myself since 95....  The OP never spoke to cutting a spring, he spoke to cutting a spring perch, lowering it, and rewelding the spring perch on, using a stock v8 spring.  A great suggestion IMO for what he's looking to do.  Some of the unique issues with the type 44/D/C4 chassis, is that it uses the swaybar as part of the triangulated control arm.  This is far from an optimal setup, and creates a lot of problems when lowered.  'Excessively' lowered on 44/v8/C4, IME, is .75in, so 1.5in (H&R typical) is excessively lowered by definition.  IME2, at 1in, you start to get excessive inner tire wear, and front tire wear is not fully corrected with camber adjusters.  Since caster is an integral part of a triangulated swaybar, there are a lot of dynamic issues that come into play.  'Acceptable'?  Depends on the definition.  

My design and practical application background is almost 20 years of type 44/v8/C4 tweeking, most of it in suspension work. From mild to wild, including over 12 years in extensively modifying, tweeking, reworking and revising this type 44 suspension for full race:
http://forums.audiworld.com/album.php?albumid=37342&pictureid=99119

You can certainly use a 5ktq spring on a v8, because it fits.  But to the OP, he has put forth the best mod for what he's attempting to do IMO.  Many here *read* cutting spring, but that's different than cutting a spring *perch*, which is actually what the OP said.  To suggest using a lighter *rate* spring to lower, doesn't *just* lower, that's my point.  It lowers the car via spring *rate* (diameter), which will make it handle much differently than lowering the stock spring perch with the same length and rate spring.

I'm not here to prove right or wrong, only point out that possibly the OP had the right answer for what he was trying to do, and too many read what he posted, incorrectly.  Creating a lot of subsequent confusion to the task.

Cheers

Scott J


 

-----Original Message-----
From: J123fs at aol.com
To: qshipq at aol.com; v8 at audifans.com
Sent: Tue, Mar 30, 2010 6:18 pm
Subject: Re: [V8] Lowering thought


I agree on some points, and have cad software for suspension design I have played with to back up a lot of what I have said, and confirm what you state.
I also have been racing here in NE for 20 years ( NER SCCA 2009 FSP champ), I have set up many a car, and the one thing I can open my mouth up about and not make a fool of my self is suspension design and function.
A lot of SCCA rallycrossers are swapping stock springs between similar chassis as I type this- 200 rear springs into a lighter 5000 is one of note I know of....to help raise or lower spring rate of raise ride height- change CG or roll centers- pretty basic stuff, and plenty cost effective vs, cutting and welding.
500 lbs extra weight on a V8 is not an issue onto 5000 or 100/ 200 10v springs IMHO- that's 250 or so per side (not even getting into F/R dis), and as the stock springs run around 230 lbs, so you are talking ONE inch of compression at static. Stock 5000/100/200 10V springs are not that much less rate as you might think vs a V8.
Lowering springs from H&R raise the rate a little, but are not that much stiffer than stock, they have extra coils and are slightly thicker. More coils = less rate, more dia = more rate with same # of coils, they want them to fit tight in the perches and raise the rate just a bit.
We have had some pretty in-depth discussions regarding the whole front end of Type 44's here and on the Q-List many times over, so I don't want to get into anymore about bumpsteer, ect....You are right regarding that, - if - excessively lowered. 
But CG, roll center, weight distribution also factor pretty heavy in the real world.
I stick by what I stated- some slightly lessor rate Type 44 springs will work just fine, as will lopping off a 1/2 or whole coil as long as it still fits tight at full droop.

Not to mention slightly softer front springs will help the car rotate better- something a nose heavy V8 needs.
Cut a coil off a stock V8 spring and you raise the rate. 

The end result with a lessor rate spring will soften up the front end a little bit ( = less underster), cutting a coil will stiffen it, and without doing something to the rear the car WILL understeer more.
Cheers,
Jack