This is why shocks matter.....

[Sam Strano]

Take a few minutes to read this article. Note that it's a Brembo car with the upgrade shocks. As you read page 4, you'll see why the first mod my car got was a set of Koni shocks (and later set of even higher end AST shocks for my autocrossing--though they are very, very nice on the street).

Here are the pertinent quotes from Randy Pobst--who like me is an SCCA Solo National Champion. Though he's gone onto some other things.

"That live rear axle setup? A non-issue for both of us. "The undulations I felt at high speeds in the bumps did not appear to be coming from a lack of control of the rear axle," says Randy, who suspects a damper issue. "The shocks can handle the car up to 60 to 70 mph. At 80, 90, 100 mph, we have a really challenging set of curving bumps and braking zones for which the shocks are overmatched."

But the BMW shines where it matters most: "The BMW has far better shock control when being driven hard, which gave tremendous advantage on the hairiest part of this track," says Pobst. "I don't know for sure how fast my speed was, but it sure felt a lot quicker in the BMW."
Which is why when pressed, Randy admits that he believes he set the fastest lap in the M3. So do I. "I think the BMW is faster because of its superior shock control at high speed," he says. "It has very little nose dive, very little brake dive, which gives me more confidence as a driver. It's more refined, a more conservative car than the Mustang is and far better controlled."

Read more: http://www.motortrend.com/roadtests...rison/m3_track_performance.html#ixzz0xSOW3Djv

I'm always on these forums and shocks/struts are the first thing I recommend doing to make a car drive better, because they give you confidence and stability, and when they adjustable allow you to tune how the car reacts and rides to what you want, not what some engineer wanted.

 

[irishpwr46]

im going to be in the market for a new set soon i think. i have the roush stage 2's currently. street driving with an auto-x thrown in once in a while. hopefully a few HPDE's next season. whats the recommendation for that?

 

[Sam Strano]

There are a number of choices, but topping my list is generally Koni Sports. $750, rebound adjustable and a killer warranty. Koni STR.T and Tokico D-specs and Bilstein's are also good options for dampers (vs. coil-over setups w/dampers). I also have some higher ends stuff that fits that bill like AST and KW as well as Steeda's coil-over setup. But you need to first determine if you want or need all that.

Personally I feel in most cases a nice set or dampers with or without lowering springs suits the masses the best, and of those the Koni Sports are my first choice.

12 of my 13 Championships between Solo Nationals and ProSolo have come with Koni Sports. I hope to add to that this year--and if I do it'll be on AST's which I went to for a few small, mostly autox and site related reasons.

 

[DraggnRoush]

Sam... what are your thoughts on DRAG racing shocks for the S197?

 

[Sam Strano]

That would depend on just how serious the drag racing is, and if you give a crap about how the car works in the real world....

Drag "shocks" are pretty much useless for any sort of good control and stability. In fact this is one place I'd actually probably recommend D-spec over Koni Sports. The D-specs can be made very, very soft to maximize the speed of the weight transfer--but still give you useful damping on the road. That's even more critical if you happen to take your front swaybar off (not something I recommend for street driving).

 

[DusterRT]

I'm always on these forums and shocks/struts are the first thing I recommend doing to make a car drive better, because they give you confidence and stability, and when they adjustable allow you to tune how the car reacts and rides to what you want, not what some engineer wanted.

Probably not so much what the engineer wanted, more like requirements from bean counters (M3 MSRP > Mustang MSRP..by just a little bit..), lawyers (save the people from themselves lest we be sued!), and the people in charge of marketing these things to old guys who want a smooth, soft and isolated ride..I think the engineers are doing the best they can given the constraints they have to work within!

 

[Sam Strano]

Well... Maybe both.

The stuff internal to a non-adjustable shock are pretty standard. Just a matter of what kind of pistons and shim stacks, etc you use. Basically the valving. There are some pretty killer stock valved shocks in the world, mostly German. American cars tend to lack rebound, and at times have too much compression too. I will readily admit the Brembo car's dampers are some of the best I've been in a stock pony-car. But they aren't perfect.

I'm sure a bean counter is involved, but I'm not convinced that this is something they'd have a lot of say in. Someone(s) @ Ford specs the valving. I know they do some testing and have even heard how they've done some shock testing. I think they do the best they can and do have to not piss anyone off. But Randy is on point with the comment about the shocks lacking. The BMW's offer more control as you push the car faster and faster. And that's on a race track. Stutter bumps, patches, so on and so forth are what "confuses" stock shocks more than anything, and that's because they are meant to ride well. It's a performance car, and I'd rather have control and a firmer (but not harsh) ride. And yes, money does help get you a shock that is more well rounded that has more control without more harshness as there is more going on inside.

It think there are different issues. One is the price, and less capable shocks are cheaper. So I agree there. But the second is the basic valving, and I wish the shocks had more rebound control--even if it was all the time. That shouldn't cost anything, but it would firm the ride to levels someone would probably find unacceptable. Given a non-adjustable shock option that's what I'd do. But ideally, this is why I love adjustable shocks so much (good ones anyway). They don't require you to settle.

 

[DraggnRoush]

That would depend on just how serious the drag racing is, and if you give a crap about how the car works in the real world....

Drag "shocks" are pretty much useless for any sort of good control and stability. In fact this is one place I'd actually probably recommend D-spec over Koni Sports. The D-specs can be made very, very soft to maximize the speed of the weight transfer--but still give you useful damping on the road. That's even more critical if you happen to take your front swaybar off (not something I recommend for street driving).

Sam - the reason I'm a supporting member of S197forum is because of the number of SERIOUS drag racers here. IMO the vast majority of us don't care if we're compromising street handling (I sure don't) as long as we get better 60' times, ET's and trap speeds. And yes, I took off my front sway bar!

My issue is that the front struts of my Roush allow the nose to rise rapidly on launch (a good thing) but the dampers are too soft & allow it to come down too fast and bounce up/down the first 330' of the drag strip. I can't find any really well-designed DRAG struts for the S197 (double-adjustable dampers)... I just thought I'd see if you knew of anything, but if you're mostly a "corner carver" guy, I can respect that & won't ask you to give advice for drag racing, if you're not comfortable doing so.

 

[Sam Strano]

I'm a suspension guy. I can help, but here's the issue: The bounce you are getting is because you lack rebound.... that same lack of rebound is what causes the quick weight transfer. You can't get one without the other. All you can really do it run an adjustable shock that allows you to dial in a balance between the two.

I'm happy to help, but you'll have to decide what sort of compromises you want to make.

Given what I see here, again this is one case I'd recommend D-specs to allow you to dial in the amount of shock forces you have. I carry they @ $589/set shipped. I think Koni's would be a waste for what you do, and the fact that you have no front bar means the D-specs increase in compression damping as you turn the shocks up will make the car a little more stable on the street too.

I'm not knocking what you're doing--but there is a reason that you see old Nova's running 10's on their original rusty shocks. They weight transfer, fast. But it also makes for a hairy ride (and you have the same issue). Having some tuneability would be good, you seem to know that. But frankly QA1's and that sort of damper--they are terrible shocks. In fact I've had customers 60' better on Koni Sports at times than on "drag shocks" QA1's and Afco's both.

 

[DraggnRoush]

Thanks Sam, I appreciate your help. Right now I'm running the stock struts & springs from a V6 S197. they are nice and soft & transfer weight fine... I was thinking I need compression damping to slow down the nose dropping? Rebound damping should remain light no?

So maybe what you're saying is that I need to live with it & just learn to keep the power to the ground and the front end up via faster power-shifting...

 

[Sam Strano]

Thanks Sam, I appreciate your help. Right now I'm running the stock struts & springs from a V6 S197. they are nice and soft & transfer weight fine... I was thinking I need compression damping to slow down the nose dropping? Rebound damping should remain light no?

So maybe what you're saying is that I need to live with it & just learn to keep the power to the ground and the front end up via faster power-shifting...

Compression damping is not spring rate. And the bounce is a lack of rebound damping, not a lack of compression damping. Yes, more compression might slow it down, but the compression can't stop the springs from compressing down--and they will want to return that energy, and that's the rebound's job to stop or slow down that stored energy's release. The lack of rebound is what's causing the "bounce".

Seen a car drive the road, and the whole nose bobs? That's a lack of rebound. Seen a car with only the tire bouncing, but not the body? That's a lack of compression damping. The rebound is what controls the body mass. The compression controls the unsprung mass.

I think if you did what I suggested you'd have options you don't have currently and can play with the dampers to find what works best for whatever you are trying to do at that time. Street or drag.

Drag shocks like QA1's are terrible control dampers. They are also build pretty poorly too as far as I'm concerned. They use a cheesy adjuster that is nothing more than bypass. Changing those doesn't effect the piston as it does on a Koni or D-spec, or any other decent shock including Koni all out Drag shocks.

Which brings me to my next point. Koni does make actual drag shocks, and you'll tend to find those, not QA1's on ProStock cars, etc. But they make no bones about the fact that driving those on the street is dangerous--and they are adamant about it. Could they sell more of them if they didn't say that, probably could--but it's true, the things that make them do that drag job so well make for a horrible street car, and I'm not just talking about someone who's tearing up corners either.

 

[DraggnRoush]

I follow what you're saying about the effects of rebound/compression damping - I agree with you, now that I think about it, it's the spring rate more in control of compression & the dampers smooth out the bounce via rebound damping... So a cheap improvement for me is a set of D-specs and some time spent testing & tuning the damper settings?... what about the REAL drag shocks from Koni? Too expensive? Strange Engineering is asking $500 each for their front struts... not including springs and caster/camber plates...OUCH!

BTW - I only drive the Roush to/from the drag strip & that's all highway driving.

 

[Sam Strano]

I think D-specs are the cost-effective, quick, and streetable solutiuon.

FWIW, you might want to read this:
------------------------------------
Koni Adjustable Drag Racing Shock Absorber Series SPA1

90/10 Theory Falls By Wayside
The KONI SPA1 series shock absorber (for drag racing only) is a complete departure from the old "90/10" thinking which is no longer effective in modern drag race competition.

The old thinking was to allow the vehicle front end to rise quickly and stay there to promote as much weight transfer as possible to the rear wheels. This was achieved by virtually no rebound forces ("10") and a great deal of bump forces ("90"). This massive amount of bump force was supposed to hold the front suspension up and maintain that "bite."

Unfortunately the nose-in-the-air position trapped huge volumes of air which ruined any attempt at aerodynamics so E.T.s were not as good as they could have been.

KONI SPA1 series shocks deal with this in several ways. First, they use virtually no bump (compression) damping. Why? To allow the front-end to settle quicker, restoring the nose down attitude that is so essential for cleaner air flow. Second, the rebound (extension) forces are velocity sensitive; that is, they increase at a rate directly proportionate to piston speed.

So, what does this mean?

On a dry surface with good hookup, the amount of lift generated by initial launch is, of course, very sudden and quite violent. The velocity sensitive nature of the SPA1 reacts instantly (no magic, just good design and tuning) to damp this lift to avoid bogging caused by too much weight transfer. Yes, you can have too much of a good thing.

On the other end of the spectrum, a slick surface would naturally provide less lift and tire shock, so the SPA1 then allows more movement of the front end because the lack of traction initially does not lift the chassis as violently. This "gentle" impulse does not activate the higher speed circuit of the SPA1, so you end up with more front to rear weight transfer and accordingly better bite. Not only that, they have five settings that enable you to tune your chassis. For KONI rear SPA1 shock, there is a big difference. They still have nearly zero bump (compression) damping but the rebound damping, unlike the fronts, is digressive.

Digressive means they are designed to digress, or "blow off" at high piston speed. Why? Well, if you had the velocity sensitive type setting on the front shocks use, it would be possible to grossly over damp the rear suspension on initial launch, thereby picking up the rear wheels. The rear SPA1 KONI will "blow off" then, and allow proper "unwinding" of the rear suspension.

WARNING
KONI Series SPA1 shock absorbers are specifically for use in off highway drag race competition only. If used on public highways, loss of vehicle control and consequent personal injuries may result.

 

[ArizonaGT]

This is the Corner Carver's subforum, is it not?

 

[Riptide]

Excellent information btw thanks Sam. Spelling things out like that makes things easier for us newbs to understand.

 

[Sam Strano]

I was just answering the question. Gets a little fuzzy when we're talking about dampers.

 

[foolio2k4]

Theres no matching the M3 in terms of suspension against the mustang.

We dont have electronic adjustable dampers like the M3 does, nor zee german engineering.

Mustang is built for every range of demographic. I think they did a good job on that setup.

The M3 is built as a performance oriented sports car. Ours is just a Gran Touring everyday car.

If you want better suspensioin....MOD IT!!

 

[Gray Ghost GT]

Sam, thanks for posting this information. I really like my Koni Yellow Adjustable Sport shocks!

 

[DraggnRoush]

A little "cross-training" is good for you guys LOL!

Sam your help is great.. Thanks a million!

Do the Koni SPA1 fit the S197?

 

[frank s]

Theres no matching the M3 in terms of suspension against the mustang.

We dont have electronic adjustable dampers like the M3 does, nor zee german engineering.

Mustang is built for every range of demographic. I think they did a good job on that setup.

The M3 is built as a performance oriented sports car. Ours is just a Gran Touring everyday car.

If you want better suspensioin....MOD IT!!

So, which BMW works better than a Mustang GT 5.0? At what price difference?

http://www.motortrend.com/index.html

Just to be technical about it, they lapped Willow at 0.09 difference in a 1:47 lap.