Lowering ride height on a 308 by changing spring perches | FerrariChat

Lowering ride height on a 308 by changing spring perches

Discussion in '308/328' started by Brian A, May 8, 2019.

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  1. Brian A

    Brian A F1 Rookie

    Dec 21, 2012
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    1983 US 308 GTS QV
    #1 Brian A, May 8, 2019
    Last edited: May 8, 2019
    I am starting this new thread to ask questions specific to changing lower spring perches as a means to lowering the suspension height of a 308 with stock Koni dampers. There are several threads, listed below, which touch on the topic but none describe the method in any detail.

    I will be rebuilding my suspension system sometime in the next 12 months (hopefully, maybe). Currently it is stock, original and dead-tired.

    1.) The most popular method of lowering the car appears to be installing height-adjustable shocks such as QA1s. While adjustability is nice, I really don’t need to corner-weight the car. Why is it that people go to the QA1s rather than just changing spring perches?

    2.) A nonadjustable option is just fine for me. Is replacing the lower spring perches feasible? I would want to lower the car about an inch (2 cm).

    3.) If I discover I can no longer get up my steep driveway, how easy is it to pull the shocks and return the stock lower spring perches?

    4.) I suppose an issue is that my suspension has undoubtedly sagged over the years so it is unclear how much I need to lower the car after the stock Konis are rebuilt. The fresh Konis may raise the car even more than it currently is. Any estimates as to how much this may be? Currently, the tops of my wheel wells are 27” (68cm) off the ground.

    5.) I once saw some design drawings (maybe Steve Magnusson?) for lower spring perches. Does anyone sell them? Any suggestions on how to get them built?

    6.) Et cetera.

    Three threads which mention changing the lower spring perches:

    2018: What is the easiest way to lower the car a few centimeters?

    2013: Lowering suspension on a 308

    2008: want to lower the front of my 1984 308
     
  2. sp1der

    sp1der F1 Rookie

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    #2 sp1der, May 8, 2019
    Best bet is weld on tube with threads to put adjustable spring perches on that way you keep your koni shocks stock springs and can adjust ride height. It would be advisable to maybe increase spring rate if lowered so car does not bottom out.
     
  3. dflett

    dflett Formula 3

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    #3 dflett, May 8, 2019
    For me, because fitting QA1 adjustable shocks was more convenient and cheaper than modifying my Konis to take a lower perch and having the Konis rebuilt because they were worn out. When I looked there was not a simple, off-the-shelf way of lowering the standard perch.
     
  4. Andy 308GTB

    Andy 308GTB F1 Rookie
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    #4 Andy 308GTB, May 8, 2019
    Changing the perches and keeping the Koni's was my initial thought when I wanted to lower my car. But Simon is absolutely spot on, you would need to fabricate adjustable perches. Otherwise you could be a little out in your calculations and be back to square one.
    It then becomes clear that adjustable shocks are the answer. And much cheaper too than getting Koni's rebuilt, let alone getting perches fabricated.
    Then you look at QA1's and realise there are cheaper options out there that don't need expensive adaptors to get them to fit!
    As for springs, another area where a little bit of Google will save you lots...

    Sent from my ONEPLUS A3003 using Tapatalk
     
  5. kcabpilot

    kcabpilot Formula 3

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    #5 kcabpilot, May 9, 2019
    Last edited: May 9, 2019
    If you alter the spring perches on the Konis you will need to adjust them to compensate for the new altered spring rate. They are adjustable but, as far as I can see, you have to take them apart (remove spring, adjust, reinstall spring) and as this would be trial and error since apparently nobody else has yet successfully done it you might be taking them on and off several times. You also have to compress the spring on the car to get them out (at least the back ones) With the QA1's you can adjust the spring height and then adjust compression and rebound properties without removing them.

    So you'd have to REALLY want to do this. It would be a lot of experimental work.
     
  6. sp1der

    sp1der F1 Rookie

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    #6 sp1der, May 9, 2019
    Will send you a picture of my adjustable koni shocks basically you weld a threaded tube over the standard shock body and then have threaded spring perches, I think superformance also sell adjustable Gaz shocks
     
  7. sp1der

    sp1der F1 Rookie

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    #7 sp1der, May 9, 2019
  8. Ferraridoc

    Ferraridoc F1 World Champ
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    #8 Ferraridoc, May 9, 2019
    Mate, keep the Konis standard and put them in the "Ferrari box" with all the other bits you've taken off the car. Then get a set of adjustable dampers with stiffer springs for less than the cost of rebuilding the Konis. Forget dicking around with the Konis.
     
    WaltP and dflett like this.
  9. i-velocita

    i-velocita F1 Rookie
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    #9 i-velocita, May 9, 2019
    thorn likes this.
  10. Brian A

    Brian A F1 Rookie

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    #10 Brian A, May 9, 2019
    It is interesting to see Steve's diagrams again. It all looks so simple on paper!

    I once bought a Dinan Engineering "Stage 1" suspension kit when I was upgrading my 1991 BMW 318i to a street legal track car. The suspension kit included new Dinan-spec Bilsteins shocks and Dinan-spec springs. The springs were shorter and they lowered the car. It was that simple; shorter springs; lower ride height.

    I wish it was that simple with the 308.

    Dinan provided a tuned kit. Presumably they spent as much time as they needed to optimize spring/damper interaction. The existing 308 springs and Koni shocks are a factory tuned "kit" as well.

    It just seems so desirable to stay with what works.

    On the 318i, I declined buying Dinan swaybars and installed adjustable Eibach swaybars instead. I spent a year fiddling with the things getting the handling balance to what I considered "neutral". Presumably the Dinan bars would have been dialed-in out of the box.

    My experience with the 318i affects my outlook toward the QA1s and other off-the-shelf options for the 308. While I have come to respect the vintage softness of the stock 308 shocks -- the car after all is a GT "Grand Touring" not an autocross machine -- I admit I would like less body roll and braking dive. I thinking about dealing with the roll with heavier swaybars (… and spending a year) and just living with the dive.

    Mostly though, I just want to lower the car a bit when I refresh the suspension system.
     
  11. Nino1964

    Nino1964 Formula Junior
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    #11 Nino1964, May 12, 2019
    I looked into having my Konis converted to adjustable perches. The cost was more than buying new Spax shocks and springs. Ive been pleased with the Spax and I have the Konis packed away.
     

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