Hello All,
I am researching a rear coilover setup for my car. I don't plan to do any auto crossing, but would like a nice canyon carver. From previous threads on this site, it seems that 140/150 lb. rear spring would be good as well as removing my rear sway bar, installing a larger front sway bar(perhaps one or two sizes up from stock), and keeping my stock torsion bar.
I currently have Koni sport shocks all around. It appears that my left rear shock is leaking, so I am thinking to go ahead and get two new rear shocks. If I get Bilsteins for the rear, should I change out my front shocks to match? Do you prefer Koni adjustable or Bilsteins? Is the damping control of the Koni necessary for a street car?
Any experience with the different coilover setups from Ground Control, Elephant Racing, or Tarett Engineering?
For springs, do you prefer Eibach or Swift or another brand?
I am not sure why, but Elephant Racing uses a 2.5” rear spring, while Tarett Engineering uses a 2.25” rear spring-both are Eibachs.
I don't think I will need a helper spring for street use.
Any thoughts would be appreciated.
Thank you.

You’ve proposed completely changing the car in terms of hardware, cost, and most importantly the handling balance.

The 914 is already a competent canyon carver in stock trim.

What are you trying to achieve with all the parts swaps?

I would just change out the rear if you already have a leak. I purchased ground control, really nice product and great service. You'll be able to set ride high, corner balance etc. Best, MarkClick to view attachment

KISS. Replace broken shock with like item. Install 140# rear springs.

fwiw, I am in the side of "front and rear sways". I've had several over the years and always liked that set up. I know others are firmly in the "front only" sway bar camp. Its almost as volatile as asking what oil do you recommend!

I am also of the opinion that if you upgrade the rear springs you should upgrade the front match. I'd be inclined to swap out front torsion bars for stiffer ones to match the new roll rate of the rear springs.

Whether you need a rear sway depends on what you have in the front. What are the front torsion bar and swaybar sizes?

Not trying to be a jackass but I was trying to get at was what is OP trying to achieve? Sounds like handling is the primary goal but how much ride and NVH is he willing go give up. Clearly stated autocrossing wasn't the goal so there is no point in chasing all out AX or racing setup that totally compromises ride quality. Sounded like the proposal is drastically increasing spring rates on front and/or rear. Stiffer is not always better especially on canyon roads where road bumps, potholes, and loose gravel have to be dealt with.

Trying to answer his hardware questions without understanding the goal is folly. Will likely result in spending a bunch of money and may make the car worse.

At a bare minimum the question is; does OP think the current setup understeers, or oversteers?

A second decent question is whether OP thinks the car has too much body roll? And, as comparded to what; a F1 car or 70's Chevy Caprice Classic? Followed closely by what roll metric; absolute body angle or the velocity of the body roll and how it affects transient handling.

Chasing parts swaps blindly and/or following the "secret" recipie of others may not get OP to what he wants.

I labor under the impression that people disconnect the rear ASB while auto crossing to get the car to rotate quicker. Then they reconnect the bar for the drive home. That's a lot of rear spring for a street car. Making EVERYTHING BIGGER makes for a stiff car. Poop pot of money too. Budget a corner balance and alignment in after all of the swapping. Mo' money...

Have you driven a stock 914 through a canyon?

Larger tires and wheels also add to the seat of the pants feel. DON'T like to feel every bump in the road.

Koni or Bilstein is personal choice.

The Koni can be adjusted while on the vehicle, turn the knob to soften for daily driving and crank the knob for hitting the autocross or your favorite canyon road.

The Bilsteins can be revalved, better left to the track junkie.

Yes you can mix brands in pairs front and year, a 914/6 conversion that just sold for $93K on BAT was so equipped.

At least in the rear, the Bilsteins have grooves in the body so that you can move the spring perch.

http://www.914world.com/bbs2/uploads/post-87-1585713596.jpg

(bottom perch incorrectly installed upside in picture, now fixed)

The choice on the 2.25"/2.5" coil springs is more than likely a person choice for the vendor. On the street you will never notice. Call them and ask?


If you don't need the ride height adjustability or the ability to swap out springs in 5 pound increments I see no reason to spend the extra money.

Follow the link in my signature for how to build coilovers. Includes a parts list.

Totally agree with @superhawk996 and others that it always helps to have a goal when changing things up. Otherwise you chase stuff all over the place, without ever knowing when you're there.

@tomeric914 really cool writeup on how to make your own coilover. Wish I had seen that before.

I put the Ground Control system with 150 springs and Bilsteins in my car. My goal was a bit stiffer setup that I could autocross if I wanted, but wouldn't make my teeth loose on the street. Mission accomplished. The ride is definitely less forgiving below 25mph. But over that speed, and in the twisties, the car feels awesome.

Here's the video of the install...


https://www.youtube.com/watch?v=HCEl24tNEfo

Many thanks to everyone for responding.
Some very different opinions/experiences/preferences but I appreciate all of it.
I have a stock sway bar and torsion bar up front. I believe stock torsion bar size is 17.9 mm and the front sway bar is 15mm.
My goal as stated was to have a canyon carver, something 45 years old updated with some modern engineering in order to have a little more spirited street car. I have driven my car through the canyons in stock trim and I don't think it oversteers or understeers, and it does perform nicely, just wanted to take it to the next level and no more. I realize that bigger is not always better, but as some of you have implied, perhaps a little stiffer could be, well, a little better.
After I posted this, I found out that there is 125 lb. spring available. Perhaps without changing the front torsion or sway bar, this might be a next level option for me.

Last year I had front rear stock bars with 160lb springs, Bilsteins and the 205/60-15, felt unsure at high speed transitioning to brakes. Replaced the front bar with a Tarrett 22mm hollow bar, way better handling. I have stock /4 torsion bars and my teen is a 3.0 /6.
I then changed to 205/55-15 yokohama's, way, way better handling, but yeah I feel every bump in the road.

I think you mentioned having a rear swaybar. If that's correct, then with stock front torsions and a 15mm front sway, you may find that the car tend toward oversteer if you put heavier rear springs and make no other changes. You could of course remove the rear sway, but I'm not sure you'd achieve much benefit from the change in that case. Maybe heavier rear springs and install a larger front sway like 19mm?