New Struts on 951 with M030 Sways
 

For some time I have been looking at replacing the struts, and maybe the springs on my 1986 951.

My 951 has its original 474 Option Konis on it. They are still good, no leaks, but I am sure they are tired after 27 years and 92,000 miles. No leaks though. And the car is the same ride height, so they did a good job.

I have looked at the various options and read about them here on RL.

As it is primarily a street 951, I have looked at, and will likely purchase the modified Koni struts from Paragon. One thing I dont want to do is lower my car any, so if the stock length springs arent available, I am thinking I will just keep the ones I have. I think they are 150 or 180 lbs springs. So I am thinking the 200 lb springs or so.

One thing I have thought about is to install the M030 sway bars. I believe the rear is the same at 18mm, but maybe not. I believe the differences are as follows:

The MO30s are 26.8 mm front and 18mm rear sways.

The stock 951 ‘s are 25.5mm and 18 mm rear sways on the 474 Option. I think this is correct anyway.

Is that correct?

So by installing the M030 sways I can get a little bit more roll resistance on the front, and a little firmer ride with the heavier springs. But without the harsh street ride of the heavy coilovers and the 30mm bars. I can also keep it somewhat "stock" too as it carries some weight at the car shows.

I am thinking of the "middle" set up of the Koni yellows not the full adjustable settings from Paragon. Because once I get it set up I just want to leave it.

Has anyone here used the "poly bronze" spring plate bearings with good success with this type set up, or is it overkill? I am going to order it all - struts, bolts, upper plates, bearings, bushings ... except the darn $500 complete strut mount. So all the parts will be new.

Any ideas or comments or better set ups that you guys have used. Thanks in advance.

Nothing huh ....

Oh well, who wants to know how I mirror polished my ash tray ?

:roflmao:

I'm also interested in this.

More-so the suspension information though. :icon107:

in for ashtray

how does your car handle? Over steer tendency? A stiffer front bar will only make the car more apt to under steer, or if it over steers perhaps neutral. You can get away with some 250lb front springs and keep your car pretty neutral on a turbo. I did the welt bushings in my spec car and like them so far. Poly bronze may be much for the street car. Maybe just go factory rubber.

The factory suspension is the best bet for street driving. It has substantial capability as is. Suspensions changes should be done as a matching package, which can get expensive. If you just stiffen the front then you end up with excessive understeer. When you get upwards of 200 lb. springs and heavy sway bars, the car will rattle your teeth and follow every crack in the road. Spend the money on new rubber bushings, a good alignment and tires. New Koni's will never hurt either.

Thanks guys. I was just seeing what others might have done with the same set ups.

That is essentially what I am going with is 200 lb springs and matching rears, so maybe only 10% up on the stock factory rate. The sway bar is only 1mm more which of course came with the M030 set up in the next years production 951's. When mye car is pushed some it rolls a bit more than it used too.

I will go with the Konis - I almost thought of putting something cheap on and sending my 474s for redo at Koni. But alas over 27 years something has to be tried different. But it tells you how long it CAN last.

Yeah boost I feel as though my car slightly under steers now and always has. I dont ever remember wagging the tail out but once. I have always used the stock rubbers as I dont like the red poly stuff in a street car with it super hardness and noise too.

It is wearing brand new Bridgestones as it has been doing for a while. I dont think this car has ever worn down a set of tires before it has gotten new rubber on the ground. ;)

Best to send the M474s in for rebuild if you can wait for the turn around time.

Upgrade from the stock 25.5mm front bar to the Turbo S 26.8mm bar is not significant. Probably want to look for the 968 M030 30mm front and 19mm adjustable rear (although last I heard they are no longer available new from Porsche, and are much more $$ than the Turbo S bars when found used).

Stock spring rate is approx 125 lb/in.

If you go up to 200 lb/in in front, the rear spring balance will be off (23.5mm stock torsion bars). Not really worth upgrading the rear torsion bars for such a slight spring rate increase, so one option would be to leave the front sway bar stock and increase the rear sway bar (maybe something like the 22mm weltmeister bar) to offset the increased front spring rate.

^^^^^

Good info. I dont want to get the car so stiff it jars me. But the 474s were 2- 3 months to rebuild last time I checked. I have "heard" that they do them anymore but I should at least check it out one more time. The 30mm sways are prob too much for me for the cars use.

Thanks.

Back available...finally, although for some reason Porsche contracted with H&R to make the front bar and it's measuring a bit under 30mm...go figure. The rear bar hasn't had any supply issues that I recall.

Koni still does the rebuild but as you an and Oddjob mention, it takes a while. We usually have them converted to double adjustable and revalved but just a standard rebuild is available too. I bit higher cost on the M474 struts if you want them converted to externally adjustable as that requires a new piston. All doable, just allow some time to have it done. You can always set your M474 struts aside and do the cut the strut conversion on a readily available set of Sachs struts...that way if you ever want to do something with the M474 struts you'll have that option.

With regard to the swaybars, I'd consider the M030 bars to be perfect for a street car...I even have them on my 89 951 which has every suspension mod we sell.

Are M474 struts not adjustable? How much does it cost to have them be double adjustable? I have gotten a quote of about $200 to rebuild one.

They are adjustable for rebound, just not externally adjustable.

Jason - Thank you for participating in this thread. We have the right man on the job here now :thumbup:.

Sometime next week I will give you a call and see if I can get this project going.