After almost 20 years on the road, it was time to refresh the suspension on my 2001 Porsche 911 Turbo. I decided to go to the aftermarket and to install a set of Ohlins Road & Track coil overs, along with Tarett Engineering drop links. What follows are my thoughts tracking my decision making, install, and the results, along with plenty of photographs. Don't miss the before and after photos at the end...
10/1/2020: A Certified Rennlist Engineer
Armed with just an internet connection and a Rennlist forum membership, I have cautiously approached maintenance and modification on my Porsche.
I bought this car used in 2014 with about 49k miles. In my first few years of ownership I have addressed:
- Maintenance, including plugs, coils, air and fuel filters;
- Sorted an excellent tune for the local 91 octane piss water;
- Sourced wheels and snow tires for the long Montana winter;
- Got rid of the “bumperettes” fitted to the earliest US Market Turbos; and
- Fielded various other little projects.
Now, it is time to freshen up the original suspension. Which brings me to a threshold question: What to install next?
The original suspension on my car was a compromise. This is typical of car design and engineering, which are a constant compromise between unfettered inspiration, and the practical realities of marketing, budgets, and regulations. This is particularly evident in the suspension fitted for the U.S. Market 996 Turb (which was different for the rest of the world (“ROW”)). The Porsche marketing boffins in America wanted a softer touring type feel to the suspension which they believed would have broader appeal to wealthy U.S. doctors, lawyers, financiers and other hucksters who could actually afford this car. Keep in mind that it cost about $175,000 when inflation adjusted.
Porsche’s own budget in the late '90s was on a strict diet after the well loved but not profitable 993 era of 911s. And U.S. crash and pedestrian safety regulations differed from the ROW, requiring about a 20 mm higher ride height in front, and front "bumperettes" on the earliest builds. The result was, and still is an incredibly capable car. But even then there was room for improvement, and now the aftermarket has supplied a solution, and one with 20 more years of technology behind it.
While I have heavily modified past cars, my tastes have changed over time. Part of that has to do with appreciating a more subtle appearance, part has to do with more interest in reliability, but mostly, it’s a realization that it is really hard to do better than the degree holding engineers with a billion dollar R&D budget and a career’s worth of time to devote to the project. When educated only by an internet forum full of... opinions, not to mention a limited budget, improving on what the original engineers accomplished is far from a given. But that is not to say that you can’t make any improvements.
This is especially true where the original manufacturer was forced to make concessions that don't apply to the downstream owner. The suspension on the 996 Turbo is a classic example.
The 996 911 Turbo suspension was different for the US market than the rest of the world ("ROW"). It was softer in corners and rode higher than most enthusiasts wanted, but at the same felt harshly damped on uneven roads. Today it’s not bad, but with 20 years of improvement in suspension technology, and a 4x4 ride height, this is one part of this car I think I can improve upon. Here are the three options I am debating:
- Option 1, replace with original equipment: as discussed above, based on ride height alone this is off the table;
- Option 2, ROW suspension: remains a good choice to address the height and firm up the ride, but it misses out on the latest suspension technology and yet is close to the same price as the best aftermarket kits. A bonus to the ROW suspension is that it is probably more attractive to subsequent owners than an aftermarket kit; and
- Option 3, aftermarket suspension: addresses ride height, captures latest technology, but is the most expensive option and my be a detraction to potential buyers.
In the end the lure of sophisticated tech that promises not only sharper handling, but vastly improved damping on all surfaces wins out. With Option 3 chosen, the next question is which system?
1/15/2020: “Image is Everything” - Andre Agassiz
First 2 pictures: 996 Turbo on the original suspension, showing US ride height,
Wheels are Forgestar F14, custom offset, Bridgestone Blizzak tires.
3rd picture: Euro ride height
photo credit pic 3: WLS Motorlegenden M. Schnabel
My criteria for an aftermarket suspension: improve overall ride quality, cost less than $3,000 in parts (arbitrary choice, but you’ve got to draw the line somewhere), and well sorted for the 996 Turbo (I’m not interested in being a test mule). Also, the amount of drop is important. While Montana roads are delightful to drive on, they are rough and a car that can't clear a big frost heave or a steep gravel shoulder will not do well out here.
While there are many good options from KW, Mouton, and JRZ, I am focusing on two very popular options for the 996 platform: The Bilstein PSS10, and the newer Ohlins Road & Track. Both are street oriented suspensions that are track worthy, and both have solid reputations. Both were recommended to me by various sources both in the flesh and in the forums. The Bilstein system was introduced first, and was long a go to staple for road oriented coilovers. Few people have anything negative to say, but a few years ago Ohlins entered the mix with Road & Track. The Ohlins clearly garner the most enthusiasm. They also look better (and as Andre Agassiz once said, “image, is everything”), and the Dual Flow Valve technology marketing lured me in like a kid to Cocoa Puffs (Made with Whole Grains!). Of course once you add the recommended Tarett extended drop links I’ll have blown my budget, but as I said, it was arbitrary anyway. So, Ohlins Road & Track it is. Mmmm, shiny and gold.
2/24/2020: “Just Do It”
As my grandmother always said, “if you want something done right, then hire someone who knows how to do it right.” She also said, “if life gives you milk, make lemonade.” So consider the source. But anyway, I must admit I’m ashamed that I’m not car guy enough to do this myself, but I also want these things installed the right way up. If it were his car, my Revo Garage partner Dan would do it himself, and probably do it well. Fuck Dan. I’m going to one of the only two mechanics in this entire valley who has experience with Porsches, and his name happens to be Dan. He works at an Audi/VW dealership so I'll call him Audi Dan, but used to work for Porsche. We were connected by a fellow Porsche enthusiast, and I got a really good feel for the relationship. He was fine with me buying all the parts myself, and he is going to install them, and perform the alignment over the course of the next week. His estimate is for 10 hours for install and alignment. Unfortunately that'll be at Audi/VW dealer tech rates, but they are actually lower than the rates of the local Porsche indy shop.
3/2/2020: The Aftermath
Last Monday morning I dropped my car off with the requisite parts inside (gotta love the versatility of a 911!), and by the end of the day Tuesday the install was complete, the alignment performed, and the car was awaiting pickup in a quiet corner of the repair bay at the Audi/VW dealer. Audi Dan dialed it up right. He booked 10 hours for the whole project, which, without having done any real comparison shopping, seemed reasonable to me (for reference, BBi said they spent 15 hours on their, albeit including a corner balance). The results are as good as I hoped.
Specs and Driving Impressions:
The spring preload was set to Ohlin's specification/recommendation (5 mm), and the ride height was set to what is described as the "target" height in the owner's manual. By my own measurements, the front is about 20 mm lower than US stock height, and the rear about 12 mm lower (ground to peak of fender well, see pics from before above, and after below, measurements before settling). After a week of driving, this seems to be an appropriate height for the local Montana roads. If you want to drive your car here for more than about 2 months a year, you need to be prepared for adverse weather and road conditions. The current ride height (which I believe to be about ROW height if not a tad lower) is still functional and not a handicap.
The dampers are adjustable front and rear, starting at "0 clicks" for track use up to "20 clicks" for street use. Audi Dan set mine at 15 clicks, so well into the "street use" range, which I think is appropriate for the local conditions. Before describing driving performance more fully, I should specify that I am currently on a full winter tire, the Bridgestone Blizzak LM-32. These are noticeably squishier than the Bridgestone Potenza S02As I run in the summer. This is especially evident in the steering feel, and I have what I believe to be a slight imbalance in one of the front wheels that I feel at speed. I won't really be able to exercise the new suspension until I mount my summer setup. Regardless, the car instantly feels more taught on the Ohlins. Body roll is reduced, and squat and dive under braking and acceleration are noticeably reduced. I think it is fair to say that the damping is overall better with less crashing over harsh features, and very quick recovery from uneven road surfaces. We have a notorious road in town with very bad frost heaves, camber towards a ditch, and a generous 60 mph speed limit. This road is an amazing test of a cars suspension, and the Ohlins did quite well. I will say that although these are very well damped, I would not want them any stiffer for local conditions.
Alignment was set to Porsche spec for the Turbo, except for the front negative camber, which was set closer to GT2 specification at 1.1 degrees (neg). The car is driving beautifully for street driving, tracking straight and with little tramlining. The car was not corner balanced. The installer did not have corner balancing capability. Is this necessary? Should I seek it out (may have to drive to Billings or even Salt Lake City?) Please provide your comments on that below.
The big visual differences are the drop and the front negative camber. To my eye, the difference is night and day. The car sits flatter, the front wheel gap is less pronounced, and on the whole the car looks more purposeful. Interestingly, most non-enthusiasts see no difference whatsoever. My wife has absolutely no idea what I'm on about. I admit it's a small amount of actual movement, but the overall effect is a radical change to my eye. I'm thrilled with the results.
Here are before and after shots, one on top of the other:
It's only been a week, and I've driven sporadically at that. There is more to be done including playing with the damping, sorting out the vibration from the tires (that was there before the install, so I don't believe it's related), and perhaps even tweaking the ride after some time has gone by. Also, the look with the stock turbo twists with the summer tires should be quite different, and I'll continue to get a feel for driving dynamics once the summer rubber is on. I'll continue to update as my thoughts progress...
4/10/2020: Never Say Never
After about 30 trouble free miles, I turned into a parking lot with a steep entrance the other day and heard a bit of a "clunk" from the front right suspension. As I made my way home, I heard it again when apply steering lock over uneven surfaces (like turning back into my driveway). I got the car up on jacks and took the wheels off, and sure enough, I found the culprit. The end link has been rubbing against another suspension component (I don't know what it's called). My vanity was wounded first, realizing that the sexy new red plated end link was nicked up. However, when I got it off the car, I realized it worse than that, and the link itself was badly bent (below).
A quick review of Tarett's installation instructions shows that the passenger side link should be installed on the inside of the sway bar, while the driver's side should be mounted on the outside. Having heard that the Tarett links can be finicky to install I provided a copy of the instructions to the installer, but looks like they went unread. I also noted that the lock nut which is supposed to secure the adjustable portion of the link was not tightened down. Sloppy. I took the time while the car was up to go through each bolt and attachment on the new setup as well as to measure and compare the preload and ride height adjustments against Ohlin's recommendations, and I have yet to find anything else out of joint.
The jury is still out on the installer's response. He sent an email in which he seemed to both take responsibility ("we'll make this right") and seemed to suggest this is part of owning a complex suspension system (these systems have "increased adjustment and maintenance.") I disagree with the latter, and I'm viewing this as an installation error which led to a broken part. In any event the installer has asked to wait to address it until our shelter in place order here in Montana is lifted. You can't argue with that right now, so I'll be patient.
But not that patient. I ordered a new part, and I'm going to install it myself. The website lists them in pairs, and so I originally ordered a whole new pair, but Tarett offered to sell me just the "link" portion that bent, at about 10% the cost of a whole new pair. I'll use the connecting hardware off the old unit.
The repair goes down this weekend. Wish me luck!
Coronahaul: Core-oh-na-hawl; (n, v used with object), to overhaul, repair, maintain or otherwise care for a mechanical part while social distancing, particularly derived from the Coronavirus Pandemic of 2020.
Fixing the bent end link has turned into a full Coronahaul. First, the end link:
I received a new link in the mail, and screwed in the rod ends from the old link which are essentially like new. I installed yesterday, and all looks to be in good shape. When installing on the inside of the passenger side sway bar, the link has more clearance to the wheel carrier, and still has adequate clearance at either end of the steering lock. I adjusted the length of the sway bar by loading the suspension on ramps. The car sits low enough now that without ramps or a four post lift it would be very difficult to get an arm under there to adjust the length with the suspension loaded, so the ramps are huge help. After that, I raised the car back up and phased in the rod ends according to Tarett's instructions. With my wife at the wheel (she loooves helping me with car projects), I confirmed that neither the link nor the rod ends are binding at full lock in both directions. The install looks good to me, and I'm hopeful to this slight hiccup is just that.
Over the past week or so while the car has been up on jacks I've got into some cleaning that I would never have bothered with under normal circumstances. I cleaned each wheel well including degreasing the "Big Red" calipers, scrubbing the plastic liners, cleaning excess grime suspension components, and wiping down my shiny new coil overs. I also polished up the exhaust tips. They came out OK, but I'm looking for a better product than the Maguiars metal polish I used.
This week my Coronahaul continues with an oil and filter change. I am using Motul Sport Ester 5W-40. This oil came highly recommended to me by a tuner and all around Porsche 996/7 Turbo guru named Kevin (Ultimate Motorwerks).
[A side bar about the tune: year or so ago I sent Kevin a bunch of datalogs, and he made a tune for me to optimize performance and safety using the local 91 octane gas. This was essentially a "detune," as I was getting a fair bit of knock-retard from the engine on 91 using the stock tune. While I was still within the safety threshold at stock, he was able to reduce retard close to zero throughout the rev range while giving the engine a stronger more tractable pull throughout the band with some tuning. I highly recommend Kevin's services whether you are looking for a tune to match your gas, to make big power, or a consultant to help with your 996/7 Turbo. Look him up.]
These engines commonly burn oil, and some consumption is not a problem, but I have found that with 5W-40 I am consuming less than the prior owner (who tracked consumption using spreadsheets!). The ester based "Sport" line from Motul is harder to find (there is no dealer in Montana, I have to order online), and it doesn't even show up on their US website, but the numbers are good, better than the more popular 8100 Excess more commonly used here in the 'States. If you're into this sort of thing, check out the viscosity at high temps, and viscosity index compared to the Excess line, in the following links:
Motul Sport Ester 5W-40
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