Lowering a 308 with original Koni shocks

I've always been bothered by the stance/ride height of my 308 GTB. I like to keep my car as original as possible so I did not want to go the QA-1 route. I tried changing springs (on the original Konis) but I was not happy with the results.
The next step was to implement a solution that has been round for a while, but not too many folks have done. Build a set of lowering spring perches to replace the stock perch on the Koni shocks.

Here are the basic steps:
1) Buy block of steel
2) Remove any material that is not your new spring perch

Well, not quite that simple, but 3 hours of machine time later a new spring perch emerged.
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Hey, very nice work! Is this as far as you are in the project? Do you have a picture of the car with the "undesirable" height? How much lower are you trying to go?

 

Special thanks to Mike C who helped me with drawings and Steve Magnusson who did the original design.

I'll post some before and after pictures once I get them installed on the car.

 

This is a shot of the car when I first got it:
http://www.ferrarichat.com/forum/showpost.php?p=139228151&postcount=15

I have since changed out the TRX's for some OEM 16" wheels. It doesn't look too bad with the taller section TRX tires, but with the lower profile 16" tired, the gap looks pretty big. The front of the car is also 1/2" to 3/4" higher than the back. The new spring perches will lower the car 1". I left some extra material, so I could machine them a little more for an additional 1/4" drop if needed. I made fronts only to start, since the front was higher than the back. I'll decide if I need to make a set of rears after I see how it looks with the lower front.

 

Beautiful machine work.

 

+1. It is amazing to see the talents of F-chat members. Something new every day.

 

Great looking work. I have a question since I really know very little about this but like the idea. In lowering that perch doesn't that reduce the amount of "preload" on the spring and make the ride a little bouncy-er?

 

Love the idea specially if it lowers the car by an inch.

 

I was going to ask you why it looked like there was more material above the half-rings than the original design, but this explains it -- you'll want more (but please give me feedback about the A-arm clearance both as-now and if you go lower).

LQTM...

 

I don't know. It will reduce preload in that the shock will be under less tension (if using the original spring) sitting on the bench, but once it is installed the weight of the car will compress the spring roughly the same amount as before. It shouldn't really impact how the car rides, but it will reduce the total amount of suspension travel available before bottoming out.

In my case, I selected slightly stiffer springs to compensate for the reduction in travel. In theory it should take roughly the same amount of force to bottom out the new set-up as it did the original.

I do know that people have run dropped perches with the original springs and have not reported any problems. I'll post my driving impressions once the project in finished.

 

No, the spring rate of the spring is not changed and the load on the spring and length of the spring (chassis at rest) are unchanged (so the dynamic behavior is unchanged). There is definitely less vertical compression travel distance available to hitting the internal bump stop inside the Koni -- so if you were in a lengthy high-g corner on a track that would be a negative, but for rational street driving I never noted a problem.

As ztarum photo shows, most late 308QV ride particularly high -- here's where my ex-'78 308 (with 16" QV wheels) was after lowering the front 30mm and raising the rear 15 mm (have never seen a late 308QV that needed to be raised at the rear ):
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Thanks guys.

 

I have a 89 328 that is 1/2 inch higher on the passenger side. I have tried swapping springs left to right and it is still the same. I can use 2 of these perches. How much ?

 

I just put my front end back together and the car looks like it is going to be considerably higher than before and I was just mulling over exactly this same thing earlier today as an alternative to QA-1s. What a heck of a coincidence. I can do little things on my lathe, but I don't think I'm this good, especially in steel. Nicely done!

 

Ztarum,
So what clearance do you have now? below the front of the euro spoiler, i have a 1983 QV with the euro front spoiler and have to be careful with how low it is, but love the look.

 

Nice job Zack. Anxious to see it. We should go for a spirited drive when you're done.

 

What kind and size of lathe do you have? They aren't technically difficult to make, but they are time consuming since you are starting from solid and then turning most of it into chips. It would be a snap on a CNC machine, but they take 3+ hours each on my manual lathe.

My car is a euro, but does not have the deep spoiler. As a point of reference, my car (before) measured just over 27" from the ground to the top of the wheel well opening in the front. In the rear it is about 1/2" lower. This is with the 16" wheels and standard size tires.

Now that sounds like a good idea.

 

Nice looking!

Alternatively, you could have painted a bunch of QA-1's red, of course...

Or use a shorter spring.

 

Thank you. That makes sense. So threading the shock for an adjustable perch would accomplish the same thing for those without a lathe or the skills to use one?
Your car looks great with that stance!

 

So where does one get that done?

 

Exactly the same situation -- the thread-adjustable lower perch just has more possible easily-obtained positions; whereas, each fixed lower perch only has one position.
However, IME the cost of the (deeper) fixed lower perch (maybe a couple~few hundred $ per pair?) is much lower than having the shock disassembled, a threaded collar welded to the shock lower body, and the shock rebuilt/reassembled (~$600 per shock last time I checked with Truechoice www.truechoice.com, but that was some time ago) -- however, if I was having my shocks rebuilt anyway, I'd probably opt for the threaded design.

It is true that usually people go to a higher spring rate when lowering since the range of motion is more restricted (so for the same dynamic load the spring deflection is less), but that does stiffen the ride.

I definitely prefer the 308 coachwork with a little forward rake stance-- but most have a backward rake stance in stock form.

 

Yeah I was just chatting about this with a fellow chatter the other day.

I'm really on the fence about doing this with 308 #2 vs. going for the QA1's. I'd be more inclined to do it if the threaded collars are available to just weld onto the shock bodies ... I had the feeling I had to thread the actual shock body to clear the spring, etc. but maybe not the case ... anyone sourced out the threaded pieces?

cheers

 

Would these work: (I think they don't weld these)

http://www.koniracing.com/sleeves.cfm

 

Someone needs to check the shock diameters AND the clearance between the i.d. of the springs ... I recall that being kinda tight on the stock configuration which is why I thought the bodies might need threading ...

Also, how much does the stock spring extend after you pull the snap ring? I remember doing this on a press one time and scaring myself worrying about the thing coming out in my face so I made some fixture with threaded rods to compress th spring which is a total PITA ... might of been talked about already ... might of been making a problem out of nothing.

cheers