metroplex

I installed the HD Bilsteins on the rear of my 07 GT a few days ago and my initial impressions were about the same as the Bilsteins I installed on my Crown Vic about 10 years ago. In fact, I used the same 17mm gearwrench I bought for that installation 10 years ago. It cut down the tightening of the top nut by several minutes at least.

The compression damping feels too stiff, hitting bumps and any other inconsistencies on the road gets translated inside the cabin. It is noticeably more compression damped than the stock shocks.

The rebound damping feels less damped than stock, it follows the road a lot better but if I had any say in it, I'd reduce the compression damping and reduce the rebound damping to make it feel "softer" and track the road a bit better.

My favorite shocks have to be the Edelbrock IAS shocks. I installed these on the Crown Vic a few years after the HD Bilsteins and they're the ultimate compromise for touring and performance. I just wish they made them for the S197.

It's still early to tell with the Bilsteins as I need to test them a bit more, but the overall impression seems to be the same as those that I used 10 years ago on the Crown Vic.

CO_VaporGT_09

Have you found that they tend to 'wear in' after a few hundred miles in the past?

metroplex

Not really although others have said the same thing. They just felt overdamped for compression and rebound. I have to put these through a few more tests though just to get a better feel. I never had any real problems with the mono tube shocks. The twin tube shocks tended to wear out or lose efficiency after years of use.

I do notice that the tires seem to stick to the road better. I find myself being able to apply more power to the road after exiting a corner or turn without any drama from the suspension.

metroplex

After driving over familiar roads, here's my overall impression of the HD Bilsteins:

On smooth surfaces at speed (like a clean highway), it is like riding on glass - ultra smooth.

On bumpy roads, the compression damping is higher than normal. The rebound damping could be softer, but I can definitely feel the rear wheels sticking to the ground better after hitting bumps. The rear suspension doesn't feel like it wants to hop all over the place now. Big difference over stock.

On my Crown Vic with the factory Watt's Linkage, the stock factory crap (twin-tube junk from whatever 2 bit supplier they use, I think Tokico) allowed the rear to wiggle/waggle on rough surfaces like a mesh bridge. Just switching the rear shocks to Edelbrock IAS or HD Bilsteins solved it, and made the rear suspension work properly. While not as dramatic, the Mustang does benefit from better shocks.

I'll have to test the axle hop in the rain next.

metroplex

I was reading Fred Puhn's "How to make your car handle" book and there were a few pages devoted to the Bilsteins. It said that the Bilstein mono-tube design prevents/reduces the chance of the oil foaming or overheating and that there's a constant force pushing to keep the shock extended (most/all shocks do this) but that it was a constant force of about 40 lb due to the 25 atm (367 psi) gas pressure and that it could increase the ride height. I've heard about this happening before, where the car was slightly taller after installing the Bilsteins.

I also did more research and someone went to custom-tune their Bilsteins, but dyno'd their Bilsteins against the stock shocks. It seemed my suspicions were correct, it's damping for compression and rebound are set very stiff.

The main reason I wanted to go Bilstein was that I've heard of the Twin-tube Koni's "wearing out" after a few years, and the Roush shocks lasting a finite amount of time. The stock Tokico shocks that Ford uses for a lot of their cars are crap, and I didn't want to go the Tokico aftermarket route. I've had OEM Tokico's fail in under 20k miles on 3 brand new Fords.

Edelbrock IAS shocks were my favorite, but I don't see them available for the S197. Bilsteins also impressed me in the past.

metroplex

I was finally able to run a corner at 70+ MPH (no one chugging along in a pickup truck at 50 mph, the favored chariot of the average overweight Michigander) which has a series of bumps that sent my pre-Bilstein Mustang hopping left/right at the rear end.

With the Bilsteins, the Mustang hung through the corner very very smoothly. The bumps unsettled the chassis a little, but the car didn't hop to the left/right in an aggressive manner! I still have the stock factory control arms and rubber bushings. BTW, I did experience a slight increase in felt driveline clunks after I installed the shocks. Engaging/disengaging the clutch causes the "clunk" to be noticed more with the new shocks, it's not annoying at all - I just noticed it a bit more.

sam strano

I carry Bilstein, but I don't generally recommend them for this car. Mind you most don't find the ride objectionable... my reasons are different.

1. Non-adjustable for an adjustable price. Bilstein and current D-spec pricing are pretty similar, Koni Sports are about $100 more. But Koni Sport and D-specs give you damping adjustment that the Bilstein's just don't. If you want more rebound you can get more rebound (or less). Koni Sport only adjust that, D-specs do both (though the compression is changed much less than the rebound but it's still changed).

2. Rebound damping performance. I find the Koni STR.T to be very similar to the Bilstein, but with a little more rebound damping... but for hundreds of dollars less (currently they sell for under $400 though that might change come 9/1).

3. Mono-tube vs. twin-tube. In theory Mono-tubes are superior. Here's the rub, that's assuming all else is equal in the valving... and it's not. I sell Bilstein, and in fact I sell a lot of them for 4th gen F-bodies because of the cost (under $400 vs. Koni's that are $900 on that car). I've had a set of AST's for my car too. Both the Bilstein and AST's are mono-tubes. I've been most happy with the Koni Sports, and in fact often recommend the D-specs performance and ride wise over Bilstein as I feel they are better value.

3. Your rear bar... is too big. A 1" rear bar sends the rear hopping around more than what I use which is a 7/8" bar that's adjustable. The more you lean on a bar, the more it wants to *pick up* on the inside rear tire, unloading it. Do that when you are hitting bumps and it's going to skip around more. This is why I always try and stay very moderate on rear bars. And it's why I took the 24mm (15/16") bar off my 2011 GT the minute I could when I changed autocross classes and had the option.

4. All shocks wear. There is no magic in a mono-tube, they have seals and oil in them just like a twin-tube and in fact if you want to talk theory the 3 times higher gas pressure in a mono-tube makes life harder on the seals... but then that's not necessarily reality.

metroplex

With my 1" adjustable rear bar and the HD Bilsteins, the rear doesn't hop side to side anymore. The hop is what I wanted to eliminate. I didn't want more rebound damping. When I did research on the STR.T and Koni Sport, no one could really give me a straight answer on the actual compression and rebound damping compared to stock. What I wanted was compression rebound comparable to stock and less rebound damping so the wheels track the ground faster after hitting a bump.

The Bilsteins are growing on me. Going over the same roads, they are a remarkable improvement over stock. I didn't touch the front struts because the stock/factory units seem perfect for what I want.

FWIW, I understand that not all monotubes are created equal, the KYB Gas Adjusts come to mind... but in general the monotubes lasted longer and performed better than the twin-tubes. I have read several reviews of Koni Sports "wearing out". I have yet to hear of a Crown Vic owner wearing out their Bilsteins or Edelbrock IAS shocks. The HD Bilsteins on my Crown Vic saw several years of street use and then I sold them to another Crown Vic owner, and they still worked fine like the day I took them out of the box.

sam strano

And I just recently sold a 9 year old set of Koni's I had for my Camaro to a good friend, which I would not have done had they "been worn out".

As for the idea of the damping vs. stock, exactly what information did you get on the Bilstein's to have convinced you they were better? And I submit you did want better rebound damping (and got it). BMW's "track the road" for instance. It's rebound control that makes a car feel locked down and in the road vs. on top of it.

Of course they are a remarkable improvement over stock, they aren't stock! Any of the shocks discussed would be a lot better. I'm saying that a lot of research wasn't very accurate. I just warranted a set of Bilstein's less than 1 year old for a customer with an F-250 Super Duty. And about a month ago had a Koni order from a Mustang owner replacing his HD's, which he had broken two rears of.

As much as I hate to say it Bilstein does not equal the kind of quality it used to. They aren't bad, just overpriced and there are dampers out there that do as good or better job for similar money, sometimes less.

Remember I sell Bilstein, Koni, Tokico... even Edelbrock too (as well as others). I'm just telling you what I know, and since I sell all of them I have no reason to push one over another. Here it's moot anyway, you already bought them so this is no sales pitch. It's me trying to educate folks.

metroplex

The only data I have on the Bilsteins (shock dyno tests) indicated the rebound and compression damping tends to be a lot more than stock. I didn't want more rebound damping, I wanted less so the wheels would track the road better. Fred Puhn's book also dedicated a small section to Bilsteins saying the high gas pressure results in the shock trying to stay extended (my sore arms, even after a week, are a testament to this) and can even raise the ride height slightly (his words, not mine).

If you have shock dyno data comparing the STR.T, Koni Sport, Bilsteins, or other shocks, it'd be interesting to see the comparison.

But whatever Bilstein did for the valving on the GT, it works out rather nicely. I realize suspension settings are very subjective, but I am satisfied with the current setup. The front-end always felt good, but the rear was the area that needed improvement. What I'd change with the Bilstein is reduce the compression damping and rebound damping slightly so that they're "softer" and "faster" reacting. I have my 1" rear bar set at the "softest" setting because I didn't want to mess with the panhard bolt for added clearance, but it feels like a good setting.

My 09 Cobalt SS Turbo has a great factory suspension setup (factory Sachs struts/shocks), and now my GT feels/behaves a lot like the Cobalt in the same corners at the same speeds.

Do they even make Edelbrock IAS shocks for the 05-09 S197 GT? Those would have been my first choice to try on the Mustang.

metroplex

It's been awhile, but I thought I'd provide some updates on the Bilsteins. The feedback remains about the same. The rear does hop noticeably harder on rough surfaces/bumps, so I feel more of the road, but it is nowhere as aggressive as my Cobalt SS.

I've finally had a chance to put the Bilsteins through the ringer with wet pavement/rain. They did reduce some of the aggressive wheel hop I experienced in 1st and 2nd gear. Instead of just slamming the rear of the car up/down rapidly in 1st AND 2nd, it is tolerable in 1st gear and tends to disappear once in 2nd gear although I am still spinning the wheels if I use too much throttle.

I have to give props to the 414-440 hp 2011-up 5.0 Mustang and the GT500 owners who drive in the rain.