Sway bars : an update to John Hrinsine's table

Discussion in 'V8 - Performance Upgrades' started by GEN 3 SHO FAN, Apr 7, 2015.

  1. GEN 3 SHO FAN

    GEN 3 SHO FAN SHO Member

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    For those who know about this table, I refer to the V8 SHO page site :

    http://www.v8sho.com/SHO/SHOSwayBarsSuspension.htm

    I compiled some more advices and make more measurements which they are not on the first table. Few bars and combinations are not present in the first table too and it’s why I make this update. In the same way, these notes illustrate how the stock configuration it’s not appropriate for the weight repartition of the Gen 3 (V8 + auto transmission + front drive wheels) which is about 60-66% on the front and 33-40% on the rear.

    The stiffness of a bar can be obtain by this easier way :

    K = (diameter in mm x 500 000)4 (exponent 4) / 63 782 791 699 295 223 179 326 546, 59

    For example, the aftermarket adjustable rear bar from SHO Shop of 29 mm (not in production anymore) had a K of 693.1 and is 543 % stiffer than the stock 19mm. (!) Others bars can be found like front 23mm and 25mm bars and rear 25mm and 28mm bars. Lots of combinations are possible with all this variety.

    The evaluation of the balance between bars is based on the ratio of the stiffness (K) between the front sway bar and the rear sway bar (Ratio = K fsb/ K rsb).

    Sway bars 2.jpg

    The comments are optimized for Gen 3 SHO cars with SARC system but with no other modification on suspension or wheels with summer conditions. You must note that some bigger bars can generate lots of vibrations and noises (NVH) with the stiff electronic suspension of this generation (96-98/12). The stiffer combinations will be better for summer conditions or track conditions. Many others elements can make changes too (based on many comments I rode) :

    Stiffer frame = + oversteer (Gen 3 SHO stock frame)
    Stiffer suspension = + oversteer
    Harder rear tire pressure = + overteer
    Low profile tires (17 inches and higher) = + overteer
    Aluminium subframe bushings = - understeer (+ oversteer ?)
    Front tower brace = - understeer (+ oversteer ?)

    With these modifications already on your car, think to put a smaller rear bar if you want a good balance. For exemple, Stephen Newberg has at least three of them and he still have oversteer with a 24mm/23mm combination... (see above).

    According to what I rode on the net, here is one of the better (and the shorter) explanations I found :

    "As for safety, production cars are designed to understeer at the limit because it is a stabilizing characteristic. Regardless of what the driver does (increase steer angle, increase braking), the car will plow (understeer) until the radius of the turn is large enough that the grip from the front tires is sufficient to keep the car turning at that radius. Oversteer is an unstable reaction, where the car will continue to spin unless the driver reacts appropriately (countersteer, less brakes). Steady state oversteer is a bad thing, ideally you want a neutral car that will oversteer on the application of power (from the rear wheels). You could setup your FWD to oversteer at the limit and learn to control it by applying power to the front wheels, but for a street (winter) driven car I would stick to neutral steer or a slight amount of understeer."

    from :
    http://forums.beyond.ca/showthread/t-231732.html

    Feel free to leave your comments on your configuration and the feeling it's giving.
     

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    Last edited: Jun 13, 2016
  2. kevinspann

    kevinspann 87 Octane

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    Roush springs, SARCs on full firm, and 24/26 bars made for a quick reacting gen 3. Rode kinda harshly though.
     
  3. GEN 3 SHO FAN

    GEN 3 SHO FAN SHO Member

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    NHV will present for sure. Do you have understeer in curves at high speed ?
     
  4. stephen newberg

    stephen newberg Moderator Staff Member

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    Mine came with the 24 on the front and the 19 on the rear. I tried upping the rear to, IIRC, 27 and found the oversteer excessive, so backed it off to the 23 and the current combination is predictable and only slightly into oversteer when pushed. Of course, other suspension changes (on mine aluminum subframe bushings, front strut tower brace, Eibach springs) all feed into the equation also, so you really cannot view just the size of the sway bars in isolation.

    pax, smn

    PS: oh yes, and obviously tires have a huge influence and need to be considered as well. Edited to add this PS.

    PPS: I note with amusement that in the comments section I am credited with a 22/23 configuration. I am pretty sure it is 24/23, but now I guess I have to get under the car and check. :) Edited again for this PPS.
     
  5. GEN 3 SHO FAN

    GEN 3 SHO FAN SHO Member

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    Yes, we must considering others things influencing handling (tower brace, tires size, struts, springs) and the driving conditions are not the same for all cars too. I tried to make a better infos on that because the first table has comments from Gen 1 and 2 SHO and it's not the same car.

    But I always thought you (Stephen) have a 22mm/23mm combination because you spoke often about your rear size but never about your front size... (then you have a 24mm/23mm, am I correct ?). It's surprising that you have oversteer with a bigger bar on the front... Therefore, it will be normal to have some oversteer with a 22mm/26mm or a 22mm/28mm (with your first change, rear 27mm doesn't exist). It's seems to me, with your comments on oversteer, that you have a 22mm in front (maybe I missed something). The size of these bars is sometime hard to establish with precision (dirt, rust, tool used).

    P.S. Sorry for that Stephen, when I made it, I was sure that it's your configuration..:p (Don't worry it will be corrected with the right info. I will retrieve your name and put it where it's say "you have got to be kidding" !)
     
    Last edited: Apr 8, 2015
  6. stephen newberg

    stephen newberg Moderator Staff Member

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    I am almost positive that it is a 24, but will have to take a micrometer to it. Don't worry, I will emery paper the area first to take off any rust. And I think you are right, originally when I upgraded the rear to try a bigger bar, it was a 26, not a 27. Its been a long time and it gets hazy. I will check the front later today, if I have the time.

    I had the SHO out just 2 days ago, actually, and was tossing it around rather hard after I got it warmed up. When pushed very hard, I get some oversteer, though it is easily controllable. Personally, I think we are seeing the effect of the tires, which I am not at all impressed with. The Yoko Advan S4 have been a big disappointment to me and I will likely replace them far before they are worn out, just to get rid of them.

    pax, smn
     
  7. GEN 3 SHO FAN

    GEN 3 SHO FAN SHO Member

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    What's your tires size by the way ? Low profile tires will reduce understeer, no ?

    Mine are stock size 16 inchs from a unknown chinese mark otpimized for speed and water (Goodride SV308 with Z). The handling of the car is good as I can really tell if the tires are good or not... (it's the first year I have it too).
     
    Last edited: Apr 8, 2015
  8. stephen newberg

    stephen newberg Moderator Staff Member

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    With the Yokos I moved back to the stock wheels and the stock tire size. Obviously that is having an effect too. :)

    pax, smn
     
  9. stephen newberg

    stephen newberg Moderator Staff Member

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    OK, my chunk of emory paper and micrometer and I are back from under the SHO and the front bar is 24mm. While I was at it I thought I might as well check the back again too, and yes, it is 23mm. I sold the original 19mm that had been in the back to someone in Truro, NS, back 15 years ago or so. Oh, and perhaps of minor interest, while the car was still under its initial warranty, which I think was 3 years worth, I broke that front sway bar and Ford put a new one in at no cost. Perhaps the original was smaller (22mm?) and they put in a larger one hoping to keep me from doing it again? Might be. I know the owner of the dealership and he did try to take good care of me.

    pax, smn
     
    Last edited: Apr 8, 2015
  10. GEN 3 SHO FAN

    GEN 3 SHO FAN SHO Member

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    Ok, funny story about your front sway bar. If the service can be always like that, they will have a lot more customers !
     
  11. stephen newberg

    stephen newberg Moderator Staff Member

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    I got to know the owner of that dealership because of a great bit of customer service he provided when we first met, and hopefully it served him well also, as I bought a total of 3 vehicles from him, 2 Explorers and the SHO. The key to a successful retail business is always customer service and his was the best I have ever had. Other Ford dealerships I have dealt with have been average or above average, and next to the Porsche dealerships, the best I have used overall, but George Mosher at the Ford dealership in Bridgewater, NS was in a category of excellent all his own.

    In direct contrast, my experiences at Chrysler dealerships have regularly been so bad I stopped buying anything associated with them over 2 decades ago now and never will again. Your only vote is with your wallet, so I vote for those that treat their customers well.

    pax, smn
     
    SHOdded and Devin like this.
  12. RonPorter

    RonPorter Old Dude

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    My 99 came from the factory with 21/21 (I miked 'em). Here's a pic of the car in the Carousel at Hallett in 91, with two of us in the car. Look at the left-side tires. Virtually perfect with the stock suspension setup.

    [​IMG]
     
  13. stephen newberg

    stephen newberg Moderator Staff Member

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    Useful info, Ron. Thank you. And hello, by the way, long time no hear. Hope you are well. Nice photo too, by the way. :)

    pax, smn
     
  14. GEN 3 SHO FAN

    GEN 3 SHO FAN SHO Member

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    Pardon my question, I never made track with my car and I want to learn more. I will be glad to receive advices from Ron Porter ! 21/21 ? Did Ford put these when they retrieved the SARC suspension ?

    Which point on the photo making this combination virtually perfect ? The car seems to have a heavy body roll and the left tires seem to suffer a camber modification from the lateral force. I tought if we can eliminate some body roll it will be better for handling, no ?

    Thanks for keeping me on the road,
     
  15. 97SHO4SALE

    97SHO4SALE New Member

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    Where should I look if I'm interested in purchasing sway bars for my 97. I'm a new member and new to owning a SHO , I can sure use all the info you have to give. Bought my 1st SHO last week
     
  16. stephen newberg

    stephen newberg Moderator Staff Member

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    I do not know other than ask here on the market section. Used to be able to get them from SHOShop, but that was long ago, and I do not know if they have them any more.

    I will let Ron answer for himself for the above questions, but actually, that is not a lot of body roll. I like a bit flatter, but would not consider what is in that photo unacceptable.

    pax, smn
     
  17. 97SHO4SALE

    97SHO4SALE New Member

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    Thank for the info
     
  18. RonPorter

    RonPorter Old Dude

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    That is not much body roll at all, especially at speed with two 200#+ guys in the car. It shows neither under nor oversteer, just a very neutral stance. The 99 didn't have SARC (Thank God, IMO). You aren't going to eliminate the roll on the tires unless you go to much heavier springs. FWIW, I am not a fan of big bars, they are band-aids to cover for inadequate spring rates, IMO. You have to do a lot of fiddling with bar sizes to get the proper balance. The picture shows that Ford developed a good balance of spring rates and bar sizes on the stock suspension. The car only had maybe 30K on it at that point, so the stock suspension and tires were still relatively fresh.
     
  19. stephen newberg

    stephen newberg Moderator Staff Member

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    I agree with Ron in his comments above.

    pax, smn
     
  20. GEN 3 SHO FAN

    GEN 3 SHO FAN SHO Member

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    Ok, I put the rear 25mm bar yesterday and after some try, I can see the difference. The rear of the car is a lot stiffer than before, maybe almost too stiff for a daily driver (will see with time). Now, according the vibrations I have in the car when driving, it seems the stiffness of the car is almost equal between front and rear end (same quantity of vibrations from both).

    It will useful to say that my 1996 had his original SARC struts and springs (old and probably softer than new), the difference between when they are on (soft mode) and off is very easy to feel when the valve are closed. In soft mode, mine act like boat, diving a lot with a "medium" stop braking. I have probably some body roll because the springs are old too. But they go in hard mode not so often just in hard driving conditions (irregular surfaces, hard accel and braking and very hard steering turn, degrees in turning seem to do something, not just the speed you turn the steering)

    Between the suspension of a 1996 (SARC with 22mm/19mm) and a 1999 (No SARC with 21mm/21mm) there is a lot of differences in the spings rate too. However, Ford thought to put a bigger bar on the rear too with probably stiffer struts to have a in-between SARC on and off, offering a stable driving behavior. But in my situation, with a SARC not going off often, A bigger bar can help to eliminate body roll and compensate for the aging suspension. After just 1 day trying this new bar, I can say that it's eliminate 90% of the body roll (with normal black bushings) and it's a lot more fun to turn on a coin or take long highway curves at higher speed.

    Is your car had other modifications Ron ? If no, the understeer/oversteer ratio was around 1.04 for you, it's a way better than the stock 96-98 configuration at 1.74 in soft mode (maybe better in hard mode because of less body roll). You have less body roll and understeer because your rear struts were stiffer than mine (even when the mines were new). (The 1.74 ratio is probably more than that for me for the reason I explain below.)

    My problem is when the SARC will decide to go in hard mode (not tried already), what kind of driving behavior I will have with this new bar...? SARC system is not offering a regular driving behavior in all situations.
    Stiffer bar with stiffer struts = oversteer for sure. I can have a bad surprise.

    Other point, when we change the bar, I inspect the old one. I remarked that the bar was "eaten" by the bushings holding it all around from about 1 mm, then rather than I had a 19 mm on the rear, I had a bar acting like a 17 mm... (!) Knowing that before I bought my 25 mm, I probably chosen a 23 mm like Mr. Newberg suggest.

    I will keep you inform with the behavior of the car with this new setting.
     
    Last edited: May 4, 2016

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