Zu_langsam

Just wondering if the 86 front suspension uses the same weltmeister springs as say 87 and 88 (non turbo-s). Also while I am on the subject of front suspension, have you guys been pleased with delrin front sway bushings? Thanks

Skip

Yes, 86-88 951 (not-S) springs are the same regarding fitment.

A quick guide to swappable spring fitments:

group 1 - 83-89 944, 86-88 951, 87-88 944S, 924S
group 2 - 944S2, 968
group 3 - 88-89 951S, 944S2 w/M030, 968 w/M030

And their aftermarket options:

group 1 - Weltmeister or Eibach 200, 220, 250, 260 sport springs (lowers ~1.25", can be used with spacer to lift 1")
group 2 - H&R lowering springs (lowers ~1.25")
group 3 - 2.5" ID racing spring available in any rate, must also add adapter parts for changed spring diameter.

Our Adjustable Ride-Height Kit is available for addition to any of the above. The ARHK converts a conventional strut into a coil-over and uses a 2.5" ID spring.

Good Luck!

Zu_langsam

Thanks Skip, I have looked into your hypercoil setup w/ koni adjustables and I know that I am going to atleast order the struts within the next couple of weeks. Do you stock 86 951 koni adjustables or will there be some wait time to get them in? Thanks

Skip

The application for the 86 951 is the Koni 8641-1414S insert. This is the cut-n-drill type. If you are ordering just the inserts there is no wait. If you are ordering the struts already converted (core program), then there is a minimum 3-day wait depending on stock status when ordering.

special tool

Skip - my 3 year old daughter won't let me advance the page because she loves that friggin bird. Thanks.

Sach951

LoL Jim.

J Chen

Hi Skip,
What's the original spring rate for the M030 set-up

Skip

~160# for the late model M030

J Chen

Hi Skip,
Got another question. In your site there's an article about wheel
rates . For 23.5mm torsion bars the wheel rate is 160 lbs.
Now if the M030 front springs are rated 160lbs that means the standard
951 front springs are rated even lower. Am I correct on this ?
If thats the case, what's the wheel rate for the front suspension
using 160lbs springs.

Thanks for the advice.

Skip

I'm still unclear on this myself, as my understanding from reading articles of days gone by seem to rate the front springs as 90% effective. Lately in some correspondence with Koni-NA, they believe the front rates are only between 70-80% effective. Not hard to measure and calculate, but I just haven't done it for myself yet. In the real world, we know what works and what is popular. Generally, the front and rear spring rates should be nearly equal, biased to the front depending on driving style and chassis conditions (tire size, etc) - until they reach race proportions (>500#). At this point the rears start to slide off a bit leaving more and more spring rate toward the front. Not uncommon to see a 800# front spring rate married to a 500# rear spring rate.

FYI, the reference mentioned on our tech site puts the 23.5mm torsion bar at only 126# effective. The torsion bars married to the late model M030 optioned cars were 25.5mm (175# effective). This along with the significantly larger front vs rear sway bars would fall in line with safety measures of the day that made most cars understeer on the ragged edge so objects would be struck head-on rather than whilst sliding rear-end first (comparatively more dangerous and harder to recover from).

Skip

For your daughter, special tool - tell her the eyes are moving and watching her

J Chen

Hi Skip,
Thank you for the tutorial. This brings up another question.
I'm running coil overs all round without torsion bar. In my
initial set-up, I used 250lbs springs for the rear. Funny thing
though was that it felt so much softer than the torsion bar
set-up. Now looking at your tables, 250lbs equates to 141lbs
wheel rate in theory its 15lbs stiffer than the stock bars.
So why does the ride feel softer ? Can it be that the rate
of force in compression of springs are linear while the rate
of force in the twisting action of the torsion bars are exponential
in fashion.
Thanks

Skip

944 Torsion bars are linear springs, though they will not give the same feel as a coil-over spring. There are a few reasons why an increase in coil-over spring rate above that of the torsion bars might feel much different, and even softer. For one, the torsion bars are very heavy, much more so than the coil-springs. This gets different reviews from different folks, but the main comment is that is feels smoother. The spring is dealing with considerably less unsprung weight, and thereby offers greater/faster transient response... often perceived by the driver as smooth by comparision (less bouncy). The alter effect of removing the torsion bars is that they add rigidity to the rear suspension as a whole, and if they are removed the rear may feel a bit more floaty. What we recommend to those not wishing to install the pricey/custom metal bearings in place of the torsional rotation area is to upgrade the inner and outer spring plate bushings to Delrin. Delrin is a very hard plastic with little to no deflection - this will bring back and even improve the torsional rigidity of the system.

What shock are you using for a coil-over? This may also be an issue if you are using one of the lower quality units. Also, di you happen to increase the wheel size/mass at the same time as the coil-over upgrade?

J Chen

Hi Skip. Thank for the reply. Yes infact I did increase the
mass buy uprading to 17inch rims. I'm using Ledas coil
overs. This brings up two questions. I've converted my
86 A-arms to steel ones using Welt bushings bought
from Jason as well as a set of Derlin outer spring plate
bushings.
1. Assuming that I do did not mark the original position of
the castor block, how do I set up the alignment
correctly & what about castor adjustment ?
2. The outerspring plate bushings has got one face
which is flat while the other side is concave. Which
side is suppose to face outwards. The concave side
is slighty bigger & I machine it down slighty to get
a good fit. Is it correct to install the bushings with
the flat side facing outwards ?

Thanks again Skip

Skip

Those wheels may have increased the unsprung weight, thereby changing the suspension balance from what you may have been used to... specifically, abrupt reaction situation such as uneven pavement or potholes.

I'm not sure I follow the question regarding the spring plate bushings - do you have a picture of the situation. I do understand that the bushings do sometimes require specific "fitting" as the tolerances vary.