I’m building a 914 with a 3.0 SC motor. It will be an occasional street car and driven to the track. I do most of my events at Sebring which is rough. Running bilstein struts and 205 tires. Weltmeister sway bar in front. Stock 914 lower control arms, Elephant poly bronze bushings.

How big is too big on the torsion bars.

What size will be the rear springs.

Undetermined at this point. Need to see if Koni will rebuild my ‘73 dated shocks and what specs they support.

For shock rebuilding, try Koni retailers like Truechoice truechoicekoniracingservices.com

I run 22 bars up front and 275 springs in the rear of my race car.

leave them stock.

Build your suspension around them.

KT

I've had stock torsions and a 19mm sway bar up front for forever with Bilsteins. I recently went to 19mm torsion to stiffen it up some. Really just seat of the pants and driving focus helped me the most, but I just track drive for fun in the 914 not fastest lap. I have seen people run 21mm on the track, but they just seem so stiff for the street.

I've also been running a 3.0 and now a 3.2, 200 or 220lb rear springs. Bilsteins all around. It's always felt balanced atleast on the track.

Do yourself a favor and run some weber 40's, headers and DC19 cams if you haven't already. So much fun...

I used to run 22 and 23 front
But my brake temps came up (in the range I wanted)
With 21mm torsions

I also dropped my front brake pads 2 notches softer

I run a light -6 at 1820lbs
And believe the 22 were too stiff

I also ron a 29/ or is it 31 front sway bar

Also when you go over 20mm in the front and 220lb springs in the back isn't it recommended to have a full cage or you will start twisting the body?

I'd agree that with stiff suspension on a 914, chassis stiffness upgrades are in order.

I have 22s with 300lb or maybe 350 rears, IIRC (been a while). It's stiff to the point most of the spring is in the tire sidewalls, very stable on track or canyons but pretty brutal for just cruising around. Fully caged and reinforced tub which makes a tremendous difference in keeping the tires planted.

To me the 205 tire will limit how stiff you want to go...also which tire...super sticky or streetable.
I ran stock front torsion bars for years with a 21 mm front sway bar and 180 lb rear springs.....finally bumped up to 19 t bars.
Fast forward to big sticky tires then the 22 sway bar and 400 lb springs were needed to make to work. It is a slippery slope.

I run stock front torsion bar with 19mm sway bar and 180 rear spring and Koni shock from GroundControl. They sell a great rear spring/shock setup. Mark