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Thread: Dinan Stage 3 Suspension Upgrade

  1. #1
    Z8 Addict Z8doc's Avatar
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    Thumbs up Dinan Stage 3 Suspension Upgrade

    I have installed the Dinan Stage 3 Suspension Upgrade on my 2003 Z8. This system includes the Dinan Springs, Dinan Adjustable Sway bars (front and rear) and the Dinan Camber/Caster Plates.

    Overall, I think this is a relatively affordable upgrade that has more benefit than leaving the Z8 stock, especially if you enjoy spirited driving and the occasional track event.

    Handling is definitely improved as a result of mainly the adjustable swaybars and the increased positive caster from the caster plates. The ride quality is noticebly stiffer and at times seems to "bottom out" much more easily than stock (mild size bumps or potholes).

    Dinan recommends initial swaybar settings as follows to decrease understeer:
    LEFT / RIGHT (front)
    0X00 / 00X0
    LEFT / RIGHT (rear)
    0X0 / 0X0

    After installation of the complete suspension, Dinan recommends an alignment. Their alignment settings are as follows:

    Tire pressure 35lbs. and full tank of gas recommended with no weight in vehicle.

    Front:
    Camber: -0.7 +/- 0.5
    Caster: +6.5 +/- 0.5
    Total Toe: 0.17 +/- 0.06

    Rear:
    Camber: -2.2 +/- 0.5
    Total Toe: 0.34 +/- 0.15


    Problems I encountered were as follows:

    Alignment at my dealer was way off (see previous post on Roadfly). I got a second opinion regarding the alignment from another shop and was very close to spec. Minor adjustments to toe and camber we necessary but it now is right on specifications.

    Ride quality on the street has definitely suffered on my local streets. I have contacted Dinan regarding this and they have spoken to my Dealer but no solution as of yet. Since the Springs seem to be installed correctly, Dinan suspects that possibly the "wrong springs"(?) were shipped as my ride height is much lower than what they advertise. I have nearly 3/4 inch on the lower in the front and only about 1/8 inch lower in the rear or maybe they are defective(?), neither of which sound good to me (although I suppose anyone can make a mistake). At the time of this writing, I am still working through this problem and will report back when solved.

    Assuming the above problem to be correctible, Overall, I would give this system an overall thumbs up rating. Considering the relatively low cost ($1700 plus labor), I think this is one of the relatively cost effective ways to improve the handling of your Z8..... Although at a minimum I would recommend the Adjustable sway bars (recommend one setting stiffer than what Dinan recommends: 00X0 / 0X00 front and 00X / X00 for the rear) and is readily available through your local BMW Service Center.

    Pictures of finished product are below.
    Z8doc
     

  2. #2
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    Dinan stuff

    Great write up Z8DOC. I'm considering as well. By the way what kind of doc? Jonny
    Jonny

  3. #3
    Administrator thegunguy's Avatar
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    One step behind...

    For some reason, I always seem to be one step behind Z8doc, including at the track!

    Last week I had the Dinan Stage 3 suspension installed. In the ~100 miles following, I have been pleased with the upgrade. Overall, the car seems to have retained almost all of its dampened ride over uneven surfaces while increasing responsiveness and surefootedness. Until I get some time at the track, I cannot comment on the elimination of body roll (not too much to begin with) or handling in more aggressive situations.

    At this point, I have seen no disadvantage to the Dinan setup. The ride is in no way harsh or unpleasant, and I have yet to experience the ?bottoming out? that Z8doc mentioned, and I know he?s still working to determine if his kit included the proper parts and was properly installed.

    My installation results also differ from Z8doc with the caster plates. I saw no change in camber (which is what is intended by Dinan). From recent discussions we?ve had, I believe he had an additional half a degree of negative camber. In fact, all of my alignment numbers were pretty much on the money as quoted by Dinan.

    Dinan estimates a ?? loss in ride height with the Stage 3 setup. So far, I?m averaging a ?? drop +/- 1/16? at all four corners, but the installation tech told me to expect some additional drop as the springs break-in.

    I chose to do the suggested initial settings on the front and rear sway bars ? second hole from outside on both. I figure this will assist in eliminating a good bit of understeer without going beyond my currently novice driving skills.

    The installation shop, Autoscope of Plano, TX (my gracious plug), was kind enough to allow me to spend the day photographing the upgrade. In the photos below, you can see the Dinan parts compared to the OEM, fresh off of the car. As you will note, the sway bars are the same diameter and length as the originals ? they just allow for adjustment. The Dinan springs, however, are shorter than the OEM units replaced. I?ll add a photo of the installed caster plates soon.
     
    thegunguy

  4. #4
    Z8 Addict Z8doc's Avatar
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    I can't wait to see....

    if you can catch up!

    Gerat write up. It looks like mine is installed the same as yours so maybe I either have the wrong springs or..... a bad strut or two, and only notice it now that I have stiffer springs? Anyone have any suggestions on how to test to see if the struts are bad?

    My dealer / Dinan service is slow to try an recify the problem though, Eric from Dinan told me they would call the dealer and "handle it" thru them and made reference to possibly sending a new set of springs but literally no word yet, despite a couple inquiries to my service director.

    We will see how it goes but if Dinan and the dealer does not step up to the plate here and at least make some effort, then I will have to retract my thumbs up rating due to poor service.

  5. #5
    Sport Button On - DSC Off Z8-NL's Avatar
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    Are these sway bars stiffer then the standard ones, or is it the adjustment that makes the whole set up stiffer?? They look same thickness!

  6. #6
    Administrator thegunguy's Avatar
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    Sway bars

    The Dinan bars are the same overall length and diameter as the OEM bars. However, instead of just a single hole on each end of the bar, the Dinan bars have four holes on the front bar and three on the rear. The outermost hole on bar is at a location of equal length to the stock setup. The other inward holes allow you to adjust the connection of the bar to a shorter overall length. As you move from the outer to the inner holes, you move from understeer to oversteer, depending on your desired performance.

    So, the Dinan bars don't really change stiffness through the use of a different metal or different construction such as a tube. They achieve the desired results by altering geometry.

    While there seems to be a variety of spring/shock/strut combos used on the various Z8s on this board, the Dinan sway bars are pretty much the standard install for a modified suspension.
    thegunguy

  7. #7
    Administrator thegunguy's Avatar
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    Thumbs up Further impressions after time on the track

    One of the schools at the TMSR was kind enough to offer me a spot in a Miata club day after one of their members back out of the session. Excited at the opportunity to test the new Dinan suspension, I accepted.

    Since I've decided to keep the OE run-flats for a little while longer, yesterday's session was a good opportunity to isolate the improvements from the Dinan setup since I was at the TMSR in October. The seat-of-the-pants-meter detected a strong improvement over the stock configuration. The car was noticeably faster and more controlled in all eleven turns at the track, particularly the quick transition chicane known as the ?rattlesnake?. Some of this is likely due to my increasing familiarity with the car and the TMSR, but I'm certain the Dinan suspension was a factor.

    As a testament to the improved geometry, the OE tires had good grip late in the day, whereas in October they really gave up in the last couple of sessions, giving way to massive understeer. I will concede that the track was about twenty degrees cooler yesterday than in October, which could account for the endurance of the OE tires.

    I should have some comparison photos soon to visually examine the change in body roll.

    I also did some time on the skid pad with one of the instructors, with the DSC disengaged of course. I had not done this with the original suspension, but with the Dinan setup it was easy to control the transition from understeer to oversteer and back again.

    Now I just need to install my Quaife and get some real tires ? plenty of time before NM!

    Oh, it was a lot of fun running with the Miata group - those things are quick through the curves.
    thegunguy

  8. #8

    Great review, thanks so much....

    It makes so much sense to do one step at a time to isolate the difference, and I'm happy to hear that the upgrade is making a suitable improvement.
    Andrew Macpherson

    Expert Z8 Inspections, with full support for both Z8 sale and purchases.

  9. #9
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    I Squared

    Do you think that your DINAN upgrade has avoided any damage to the Shock Towers, etc.

  10. #10
    Administrator thegunguy's Avatar
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    No damage yet.

    I have about 500 miles on the Dinan suspension, including ~100 at the track, and I can discern no distortion to the shock towers. However, I'm waiting to hear back from my local SA about an inspection to confirm my visual assessment. My guess is that the shorter/stiffer springs would actually make the car more susceptible to damage as the suspension travel is reduced, but don't take my word for it - I'm no expert.

    If you're considering the upgrade, I'd advise holding off until there is conclusive data as to the cause of the apparent deformation and a preventative fix becomes available. Assuming that we're back in the green at some point in the future, I still recommend the suspension for spirited on-road driving with an occasional outing at the track. The loss in ride quality is minimal compared to the improvement in car control.
    thegunguy

  11. #11
    Administrator thegunguy's Avatar
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    Latest update

    On the subject of ride quality and the Dinan S3 suspension, I ditched the run-flats today in favor of the S-03s on the OE wheels. While some time has passed since I did the suspension upgrade, the ride quality returned to near stock levels. The S3 setup was already very gentle for it's performance capabilities, but removing the run-flats really made an improvement.

    Dinan S3 + Bridgestone S-03 = vastly improved handling with little sacrifice in ride quality.
    thegunguy

  12. #12
    Z8 Addict Z8doc's Avatar
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    I concur! That is what I have had since installing ...

    Quote Originally Posted by thegunguy
    On the subject of ride quality and the Dinan S3 suspension, I ditched the run-flats today in favor of the S-03s on the OE wheels. While some time has passed since I did the suspension upgrade, the ride quality returned to near stock levels. The S3 setup was already very gentle for it's performance capabilities, but removing the run-flats really made an improvement.

    Dinan S3 + Bridgestone S-03 = vastly improved handling with little sacrifice in ride quality.
    the Dinan Stage 3 in October. Overall, ride quality is good and handling is definitely much better. Highly recommend.
    Best Regards,

    Jeff
    61995 Silver /// Rot - Original Owner
    Z8 Club of Germany e.V. #102

  13. #13
    Sport Button On - DSC Off Dogsbreath's Avatar
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    Dinan Stage 3 Suspension

    I am having my Stage 3 installed this coming week. Did anyone change the shocks as well ? Or did you guys stick with the stock shocks ?

    Dave P

  14. #14
    Administrator thegunguy's Avatar
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    No change on shocks for me - still running the stockers.
    thegunguy

  15. #15
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    kept the stock shocks with the S3 mod.

    Quote Originally Posted by Dogsbreath
    I am having my Stage 3 installed this coming week. Did anyone change the shocks as well ? Or did you guys stick with the stock shocks ?

    Dave P

    maybe talk with dinan about possible different setups, potentially adjustable shocks could be nice?