Hi all.
I put in 250 pounds of batteries in the front, but I took out the spare tire (35 lb) and the fuel tank, and the headlamp motors (11 lb): so, I have a net plus weight of around 90 lbs, and I kept it fairly low in the front. Rear is about the same as it was. I seek opinions on torsion bars for the front. I’m thinking of going up to 20mm Sway-Aways in front, I have 100lb Weltmeisters in the rear.

Speaking of the rear, I’m putting in new Bilsteins. There are like 7 grooves for the bottom spring perch to sit in. My old springs were 12-1/2 inches oal. Weltmeisters are 15” oal. There are about 15mm between ring grooves…so, it’s not infinitely adjustable, but will adjust in 15 mm increments. I imagine I can get balance pretty close with the 15 mm increments? I think I put the bottom perch 3 grooves up, which makes the assembly the same length, old vs. new. I guess I’ll find out when I set the car down and align it.

TIA
Pat




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Personally, I would either keep the stock torsion bars on the front or go to 19mm like the 914-6/ 911. Too easy to overspring the front with big bars.

Does your weight delta of +90lbs include the gas tank with a full tank of gas?

Zach

Ground control makes a coil over that slips over the Bilsteins for the rear. Pick your own spring rate from a list of choices. Infinite adjustments, within the range. PMB sells them.

And not a bad price considering what you get.

https://pmbperformance.com/products/ground-...ngs-and-collars


I have 19mm T-bars in front. And it is stiff. If you are just going to drive it around the 19's might be right with 90 extra pounds.

I would worry about new TBs after the build is finished. Really easy swap. I would also decide after you get the 914 on some scales and see how it weighs out. You might even need some ballast in the rear trunk. Dialing the handling in would be the priority for me.

Does anyone have 19 or 20 mm bars available for a 914-4? These seem to be like 10 weeks away.

Probably few and far between. If you switch to 911 a-arms and adjusters, you will have an easy time finding the bigger torsion bars.

You are confusing (barely) increased front weight with a perceived need for significantly increased spring rate.

I don’t have time to lay out a white paper on how to set up suspension. Research how to calculate ride frequency.

Rear suspension ride frequency needs to be slightly higher than front ride frequency. This is done to offset the time delay between when the front suspension impacts a bump and when the rear suspension hits the bump. This makes the body motion appear to move as a unit instead of pitching fore and aft with each end of the car acting on its own.

You’re proposing the wrong change (stiffening the front more than the rear) for both ride and handling.

I am adding about 100 pounds or so to the front. Some of this is cantilevered over the A-arms. I hardly think it’s time for me to research anything I probably forgot more than you know.

Wow. Marvelous display of ignorance and bad attitude from the new guy.

You asked a question and received advice from several very-experienced members of the community. Rather than accepting advice that didn't go along with your preconceived notion that you require new torsion bars, you decide to insult someone. Not really the best tactic for getting help.

You asked the question
Why??

Apparently you already know the answer

If I were you, I would be really careful about comments like this. Lots of people on this forum have been working on 914s for 40+ years. In that time, we have seen a thing or two, so we know a thing or two.

You coming on here, having just joined in November, saying "I probably forgot more than you know." is an arrogant and frankly stupid thing to say. I myself have been working on 914s since 1985, and I don't know everything. There are people out there who know way more than I know.

Honestly, you risk alienating the members of this forum. And this site is the source of all 914 knowledge in the, excuse the pun, world. So if I were you, I would step back, and rethink your approach to this forum.

You are a newbie here. Ask questions, and open your mind to learn from people who have loved these little cars for years.

Been a busy day and just getting back to my guity pleasure of looking at 914world.

Allow me to take a bit of blame here. Most of you guys know I’m not the smoothest with my words or how I state my thoughts.

I was in a hurry this morning and didn't mean to come off as arrogant with the white paper comment. I just didn’t have time to outline the whole situation of torsion bar rates as a function of diameter, preload vs spring rate, spring rates vs roll rate, etc.

I could have stated that better.

Think with that torsion bar you propose you will be over sprung with that bar in the front.

You didn't mention anything about a swaybar and without writing a white paper that will add to the spring rate...FWIW.

MAYBE the 19 mm torsion bar with the stock sway bar with adjustable drop links...good to go.

Now...if I can just find those glasses.......


OH....I forgot...the rear set up is probably fine...I ran 140 progressives with that same shock setup...riding on rails.

My front battery is within a few pounds the original tank full of fuel, so I kept the original torsion bars. It is located in place location of the fuel tank. The rear battery, motor and inverter are within a few pounds of a stock six so I used the coil springs of 914-6. The weight is about 1 inch lower, than it is in the six.

I am with 914 teener, running 19mm torsion bars with 140lb. springs in the rear. Bilstein's all around. Ride height is 6 3/8" to the center of the torsion bar cap. Corners like it's on rails.

The original torsion bars were 17.9mm diameter. Torsion bar stiffness goes up with the FOURTH POWER of the diameter. The solid 19mm bars are 25% stiffer than the stock ones; the 20mm ones are 55% stiffer.

That's probably significantly more stiffness than you want just for adding <100 lbs to the front of the car.

I would suggest starting out by keeping the stock torsion bars and adjusting the front ride height (using the adjusters on the rear end of the torsion bars) until you get a ride height you like. Adjust the rear height as well. Then test the handling and see how much change it really needs. You may find that minor tweaks will set the car up well from there.

--DD