After either a gentle drive on your favorite winding road or a perfect lap around your favorite track, it is plainly obvious that the thrill of driving our wonderful cars is not all due to power and top speed. In fact, the most wonderful of all sensations experienced by the driver is the feeling that man and machine have become one. The single greatest contributor to this euphoric feeling is your car’s handling. If you are looking for euphoria in your 944 then keep reading. The purpose of this article is to introduce you to a proven entry-level suspension upgrade path for the stock normally aspirated (NA) 944.
Because for many years the 944 has been a popular subject for suspension upgrades and handling improvements, we are now able to buy handling component packages that have been thoroughly tried and tested by fellow 944 enthusiasts. This makes the entry-level street/track handling component selection for the normally aspirated (NA) 944 a relatively simple process. Porsche 944’s could be purchased from the factory with various levels of performance oriented suspension hardware installed (i.e., M030, etc.). This article will use as example my recent experience in upgrading the suspension of my 1986 NA 944 from its most basic stock form.
It is obvious that the standard stock suspension package for the 944 is a compromise between ride comfort and performance handling. If you’re looking for a change in your car’s handling, than you’ll love your 944 after you make the changes that I’ll be describing. While some might be concerned that a 944 having undergone these changes will be too "stiff" for daily driving, it is my opinion (others may disagree) that this set up will put a smile on your face and keep your kidneys happy. The car will feel responsive and precise on the street and incredibly safe and controllable on the track. The only change that you will notice from the outside is that the car will sit lower to the ground. However, if you wish to maintain your existing ride height you can install spacers with the new coil springs. All 944 owners with the cast aluminum type front lower control arms (1985.5 +) should be aware that you are required to maintain a minimum of 13 inches between the lower lip of the front fender and the wheel center in order to meet the requirements of the pre-track Technical Inspection. Changes in wheel diameter will not affect this parameter. The 250 lbs./in. springs used in this package have brought my otherwise stock ’86 944 to 13.25 inches. I have not experienced any driveability problems (i.e. speed bumps, curbs, etc.) as a result of the car being lowered.
The entire process that I will describe will involve the replacement of the front struts and springs, rear dampers (shock absorbers), torsion bars, both front and rear anti-roll bars, and finally tires. Please excuse any lack of accuracy in precise technical terminology.
This common package, as presently used by several Rennsport 944 owners, begins with the replacement of the stock front struts (or strut cartridges) and rear dampers with the adjustable "KONI Sport" variety. This would be followed by the substitution of the stock front coil springs and rear torsion bars, with those having increased rates of 250 lbs./in. and increased diameter of 26 mm respectively. These changes would be followed by the replacement of the front and rear anti-roll bars with larger adjustable 28mm and 22mm diameter bars. And finally, last but not least, the installation of new lower profile performance tires to make it all come together. The key to this package is that it is well balanced and provides what I consider an improvement to this car’s stock handling characteristics.
The manufacturers of the components that I used in this package are Koni for the dampers, Weltmeister for the springs and anti-roll bars, Sway-A-Way for the torsion bars, and Bridgestone for the tires.
The installation of these components each represent varying degrees of technical difficulty. While the complete installation of these components is within the reach of the average conscientious owner, you must possess a good understanding of your limitations and stay within them. Before attempting to make any of these modifications, it is imperative that you get yourself a shop manual and read the appropriate sections. I have both the Haynes ’83 - ’89 SOHC 944 repair manual and the Porsche 944 workshop manuals. Both have their good points and bad points. Together you will have almost all of the information you will ever need except for torsion bar replacement. You’ll want to get a hold of a 911 manual for that (Oh, imagine that!). The Haynes manual can be purchased at most Canadian Tire stores for $16.95. The Porsche workshop manual will cost you approximately $350.00.
By far, the easiest of these components to install are the rear dampers (shocks). Pretty simple really, raise the vehicle and safely support it on proper jackstands. Remove the rear wheels and support the trailing arm with a suitable jack. Raise the trailing arm enough to unload the damper and remove the lower mounting fastener (i.e., bolt or nut depending on style of trailing arm). Next, remove the fastener from the upper damper mount and remove the shock. Pretty simple right? Great, now the installation of the new damper is performed in the reverse order.
Attention Please!! Before installing the Koni adjustable rear dampers, make certain that you set them to full hard by following the manufacturer’s instructions to the letter. Unlike the front Koni’s, the rear ones are not externally adjustable once installed. You’ll have to take them back out to re-adjust. The full hard setting works well for this setup. The Koni adjustment can be tricky to perform if you’ve never done it before. I would recommend that you take the time to get to know your Koni by essentially playing with it at your workbench for a few minutes. Try to set it to full soft then go to full hard and back to soft again, etc. Once you feel confident that you are in fact making the adjustment properly (you’ll feel it when you get it right) set it to full hard while remembering that you must back it out by half a turn or you’ll wreck the shock in no time(read your Koni instructions!). (If you want to get technical, compress your damper and time the rebound rate. Match the other damper to this rate.)
Replacing the front springs and strut cartridge could present an obstacle to many weekend mechanics. The Haynes manual does not describe the strut cartridge and spring replacement procedure. They state "Disassembly and overhaul of MacPherson struts requires specialized equipment and training. Do not attempt to service the strut yourself." This is good advice if you don’t have the required tools. However, removal of the complete strut unit from the car is quite simple. You can easily remove both front struts and bring them to your favorite qualified mechanic. Hand him your new Koni’s and 250 lb springs and have him change the cartridge and spring for you (make sure you check for broken dust boots and bumper stops; also check, clean, and lubricate the upper strut bearing - replace as required). Once you have the complete upgraded strut assemblies in hand, proceed to reinstall as described in the Haynes manual. One point of caution, the Haynes manual has the incorrect torque setting for the "strut-to-upper mount nuts". They list it as 57 ft-lbs and it should be 18 ft-lbs. Guess how I found out? For those who wish to attempt this work yourself, the front struts and spring are easy to change, as long as you have a proper coil spring compressor and a good workbench vise. My favorite type of spring compressor is a hinged "clam shell" type with upper and lower jaws (Snap-On makes a nice one - I think you can rent them at most equipment rental shops ). I don’t recommend using the cheap ($20.00) threaded rod type compressors, as my experience has shown that they are not inherently safe. On two occasions, I’ve have had them slip off the spring and literally launch the coil just past my head. If you feel comfortable using them, it’s your choice, but I personally do not recommend them and would rather see you go to a specialized shop instead. Refer to the Porsche factory manual for the procedures on overhauling your struts.
The installation of the front and rear Weltmeister anti-roll bars is very straightforward and does not require any special tools or techniques. All I can say is read the instructions carefully and do what they tell you to do. One note to remember is that if your existing stock 944 does not have the factory rear anti roll bar, then you will have to remember to buy an additional adapter kit for proper installation. The Weltmeister bars are fully adjustable, which means you can alter two parameters; pre-load force, and effective stiffness. The pre-load force will alter the static loading at the affected corner of the car. This is accomplished by changing the length of the drop link that connects the anti-roll bar to the suspension’s member (i.e. lower control arm). This parameter becomes critical when attempting to "weight balance" the car. The second parameter, effective stiffness (anti-roll force), can be changed by altering the mechanical advantage of the drop link mounting point on the bar itself. This is accomplished by sliding the drop link mounting point either towards the rear (decrease in stiffness) or towards the front (increase stiffness) of the bar. Think of the anti-roll bar as the dependent part of an independent suspension. In other words, the anti-roll bar provides a mechanical link between the left and right sides of your car’s suspension. It’s how the right side of your car tells the left side what it’s doing and vice versa. The bars effectively limit the vertical travel of one side of the suspension in response to a change in the opposite side’s vertical position. This is how they ultimately reduce the "roll" of the car, hence the name "anti-roll" bar.
Adjustable anti-roll bars will allow you to make significant changes in the handling characteristics of your 944. A full description of the changes you can make is beyond the scope of this article, however it may make for interesting material for a future article. Suffice to say that I my case, the use of the recommended initial settings, as described in the manufacturer’s instructions, has proven to be satisfactory in this package.
Now for the bad news. Replacing torsion bars in a 944 is a royal pain in the #%@. Replacing torsion bars in a 944 is not for the faint of heart! Unfortunately, the 944 does not have an easily removable torsion bar end cap cover like the 911. The 944 end caps are also the chassis mounts for the torsion tube itself. This means you have to drop the entire rear suspension to get at the torsion bars. And once you get to the point of installing the new ones, it seems that nobody can tell you at exactly what angle to locate the spring plates in order to get the final ride height you’re looking for. So it’s a hit and miss process because you can’t tell if the torsion bars are properly set until you put the car back down on it’s wheels and settle the suspension. What you're trying to do is get the torsion bars set so that the car sits level when on the road. All this to say that this job should be left to only the VERY patient and conscientious as my initial experience took me three tries before getting it right ("read S-L-O-W-L-Y" : suspension off - suspension on - suspension off - suspension on - suspension off - suspension on). Get the point! A colorful vocabulary will also help, as you’ll need a few choice words to describe the process to your friends as you drive your car to the track with the left rear riding two inches lower than the right rear.
And finally the tires. A new set of high performance tires will also be required as your all-season 70 series Motomasters won’t cut it. While I’m certain opinions will vary, the stock 7x15 inch wheels with 225/50 - 15’s seem to be a wonderful combination for the NA 944. With this set-up, I’ve been very happy with the Bridgestone RE-71’s (225/50-15’s) on all four corners. If you only have one set of rims and you’re doing street and DEW driving, I really recommend this tire, as it seems to do everything well.
The total cost for the parts described in this project will run you approximately $2,275.00CDN (not including tires). This does not include the cost of other items you might require as a result of your upgrade process. I refer to this as the "while I’m there" syndrome. "I might as well change the motor mounts, rubber bushings, clutch, and lower control arms, etc.($), etc.($), etc.($), while I’m there". In fact, I just took at look at my receipts (Oh God!), and my total cost including tires and "while I’m there" parts, totaled $4,300.00 (so much for letting my wife Kristine proofread this article!). If this is to much for one bite (or your better half reads this article) it is suggested that you phase-in these items in the following order: Konis all around, then tires, then anti-roll bars, and finally springs and torsion bars.
I would also like to stress that you should carefully inspect all other affected suspension components during this upgrade. Repair or replace any under spec. components (i.e. ball joints, bearings, bushings, etc.). Please also keep in mind that you’ll want to get an alignment done pronto. What alignment settings to use, you ask? That’s another article for sure.
My thanks to the Rennsport members who helped me with this project as well as those who provided input for this article.
Marc Bélanger
marc_b@sympatico.ca
‘86 944 (sold - he drives a 911 turbo'd monster now)
Rennsport Region
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Copyright 1998 - Craig Seko. craig@seko.ca All rights reserved. Usual disclaimers apply.