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Topic: Actual sweet spot on shocks/struts? (Read 729 times) previous topic - next topic

Actual sweet spot on shocks/struts?

Where is the actual sweet spot on a shock or strut. Is it actually at the half way point of travel? How much on either side  of this point is still within range?  Example. If a shock has 6" of travel, is the sweet spot midway at 3" ?  If so, how much on each side of this 3" measurement is still within the sweet spot? Would 1" or 2" on each side still be acceptable? What if a car is lowered 2"? Are the shocks still ideal or should their mounting position be relocated to accommodate that " sweet spot" ?
Thanks.
84 COUGAR/90 HO, 1.7RRs, performer RPM,700DP, equal length shorties, stainless EXH ,T-5,Hurst pro-billet, KC clutch, 8.8/ 4.10s, line-lok, bla ,bla, bla.
71 COMET/289,351w heads, 12.5 TRWs, 750DP, Liberty TL, 9"/6.00s, 11.9x @112 , bla,bla,bla.

Never shoot your mouth off, unless your brain is loaded! ....I may get older, but I'll never grow up!....If you're not laughing, you're not living!  :laughing:

Re: Actual sweet spot on shocks/struts?

Reply #1
This is not on a Fox car but on my ‘70 F100 the QA-1’s have 6” of travel on the rear four link setup. The length of the shock from mounting point to mounting point at 3” of travel is 12”. I made a fixed tube steel jig that was 12” from center to center and installed the four link on that bases per the four link instructions. This allows 3” of compression and rebound from static ride height.

My guess is most dampers would want to be setup the same way.

83 351W TKO'd T-Bird on the bottle


93 331 Mustang Coupe - 368 rwhp

Re: Actual sweet spot on shocks/struts?

Reply #2
That is what I was thinking but wanted another opinion. Logically This makes sense as travel would be the  the same on either side of center.
84 COUGAR/90 HO, 1.7RRs, performer RPM,700DP, equal length shorties, stainless EXH ,T-5,Hurst pro-billet, KC clutch, 8.8/ 4.10s, line-lok, bla ,bla, bla.
71 COMET/289,351w heads, 12.5 TRWs, 750DP, Liberty TL, 9"/6.00s, 11.9x @112 , bla,bla,bla.

Never shoot your mouth off, unless your brain is loaded! ....I may get older, but I'll never grow up!....If you're not laughing, you're not living!  :laughing:

Re: Actual sweet spot on shocks/struts?

Reply #3
Shocks/struts don't have a 'sweet' spot. The damping rate is generally linear at all points along it's travel. Fancy off-road shocks will have position dependent valving, but our vehicles certainly don't.

For motorcycles/bicycles/ATSs/UTVs, sag (the amount of bump travel from full extension to ride height) is ~25-35%. I'm not sure what is for cars (which is the point of this thread  :P ), but I'd think it'd be below 50% since you want more bump travel than droop travel to soak up the bumps on the road.

Re: Actual sweet spot on shocks/struts?

Reply #4
Bringing this back from the dead as I’m due for new struts.  Here goes. The car in question is......

84 Cougar, 88 Mustang spindles/ brakes ,and springs that lowered the car 2”.

The question is....

Will SN -95 struts be the perfect solution?

I’ve searched and I get mostly answers for an 88 or the issues with the spacers. According to my research on the dimensions, the SN - 95 seems to fit the bill.
Thanks
84 COUGAR/90 HO, 1.7RRs, performer RPM,700DP, equal length shorties, stainless EXH ,T-5,Hurst pro-billet, KC clutch, 8.8/ 4.10s, line-lok, bla ,bla, bla.
71 COMET/289,351w heads, 12.5 TRWs, 750DP, Liberty TL, 9"/6.00s, 11.9x @112 , bla,bla,bla.

Never shoot your mouth off, unless your brain is loaded! ....I may get older, but I'll never grow up!....If you're not laughing, you're not living!  :laughing:

Re: Actual sweet spot on shocks/struts?

Reply #5
As mentioned, there really is no "sweet spot". The larger issue is to not be potentially banging off of the internal stops from being too low.

I've run both Fox and SN-95 struts on cars lowered about 2" or so. My current Koni's on the '83 are the Fox version, but my car is a little lower than 2".

At your drop, I'd say the SN-95 version would be fine.
Long live the 4-eyes!  - '83 Tbird Turbo

Re: Actual sweet spot on shocks/struts?

Reply #6
There is right at one inch of difference between the OEM Fox and SN95 struts with the Fox struts being physically shorter due to how they mount at the spindle.  We had struts side by side a loooong time ago and measured this when my buddy first started road racing the American Iron series.

Reason for the length difference is here:

https://www.maximummotorsports.com/tech_front_susp_9495_spindle.aspx

"Mounting ear for the strut was moved downwards, toward the ground, by slightly more than one inch, compared to the previous generation Mustang spindle. This effectively increases the distance between the strut's mounting point on the spindle and the strut's upper mounting point on the chassis' strut tower. The struts were redesigned so their extended and compressed lengths are appropriate for the SN95 chassis and spindle."

This is why all of the SN95 mustangs that are lowered typically run the Fox strut.  Some of the aftermarket manufacturers like Bilstein list one part number for the 79-04 Mustangs so take that into consideration as well.  I have heard but not confirmed that they are based on the Fox design.

83 351W TKO'd T-Bird on the bottle


93 331 Mustang Coupe - 368 rwhp

Re: Actual sweet spot on shocks/struts?

Reply #7
Bilstein list one part number for the 79-04 Mustangs so take that into consideration as well.  I have heard but not confirmed that they are based on the Fox design.

Has anyone actually run the Bilstein stuff on a stock height car?  I would hate to spend that money and ride quality still suck.
Mike

Re: Actual sweet spot on shocks/struts?

Reply #8
So that will also depend on the springs but in general Bilsteins are way better than the OEM & parts store brands of dampers.  I have run them on Foxes and also on my F150's and its like night and day.  I currently run the Koni Sport adjustables on the Coupe and Bird but I am also running coil overs on all four corners so whole different world.

I will say that the best ride my Coupe ever had was with the Tokico Illumina dampers and the H&R super sport springs.  This was with the stock K-Member and LCA's with Maximum Motorsports CC plates up front and Maximum Motorsports LCA's & stock UCA's in the rear with stock sway bars front and back.  This was a very forgiving setup as the car was a blast to drive on the street and just ate up the turns for what it was.

83 351W TKO'd T-Bird on the bottle


93 331 Mustang Coupe - 368 rwhp

Re: Actual sweet spot on shocks/struts?

Reply #9
Has anyone actually run the Bilstein stuff on a stock height car?  I would hate to spend that money and ride quality still suck.

I'm using Bilsteins on the convertible. Front struts are from a Y2K Cobra R...the car is lowered a bit in the front (and not on purpose) but I am running a bump-steer kit also. I don't imagine they're much different than, say, a stock SN95 strut as far as height goes; it's probably valved a bit differently. Rear Bilsteins are 1983-88 Cougar/T-Bird. They might have been some of the last new ones of those on the planet. But you have options with the flipped bracket/adapter/Mustang shock combo.

The convertible's ride is...different to say the least, but the Bilsteins made a big improvement over the usual Monroes that I used to faithfully use on all my past cars. They are not cheap, for sure, but are quality built. And once you wear out Bilsteins they can always get sent back to the company and refurbished. It's a nice, exclusive 'club' to be in. ;)

Re: Actual sweet spot on shocks/struts?

Reply #10
Yeah, my frame of reference on the SN-95 struts on a Fox came from the long ago time known as the 20th century, when I was working at Kenny Brown.
We had new take-off parts for days of the SN-95 stuff. Hell yeah I'm gonna use free parts on the daily drivers.

My 3 examples(plus one non-TBird) I remember that all used new SN-95 factory take-off struts were:

1. 1985 30th Anny Tbird. Stock springs, and machined the spindles to run the narrower SN-95 struts. No issues.
2. 1984 XR-7 turbo. Same set-up, spring-wise, as my current '83 Tbird. C-Kit front springs, so low in the front. SN-95 spindles. No issues.
3. 1980 XR-7 (This was after my time at KB, but still had a set of the struts kicking around when I built it. Same set-up as #2, so low, with SN-95 spindles. Again, no issues.
(4. 1980 Mercury Zephyr. Unsure of springs, but slightly lower than stock. SN-95 spindles. No issues.)

As mentioned, a lot of aftermarket manfs just lump them all together as '87-04 (or even 79-04 for some of them), so who knows what spec (dimensionally) they're using.

Unless the car is slammed to the ground, you shouldn't have an issue with SN-95 -spec struts, if that's what you find.

Long live the 4-eyes!  - '83 Tbird Turbo

Re: Actual sweet spot on shocks/struts?

Reply #11
Thanks guys!   I dont like how my car rides currently.  Stock front springs (half coil cut) and Tokico blues for Fox mustang.

pretty jarring over small bumps, and Im tired of it being so low, i get some rubbing under hard cornering.  Gonna put in some V6 bird springs or V8 SN95 springs and change to sn95 struts.
Mike