1.03 torsion bars ?

[andyf]

Torsion bar stiffness is Diameter to the 4th power. So a small increase in diameter can add a lot of stiffness. The 1.03 bars will be almost twice as stiff as the 0.890 bars. That is a big jump to make, you'll feel the difference that is for sure. Do you have a big anti-sway bar on the car? If you don't have a big anti-sway bar you might install that first. A big bar would be a better investment than bigger torsion bars. If you do have a big bar on the car then sure, step up to the 0.940 or 0.960 bars if you can find them. You won't want to ride in a car with 1.03 bars with KYB shocks. It will feel like you're driving an empty dump truck. The 1.03 bars will feel okay if you have good shocks. If it was my car I'd put Koni shocks on there since they are adjustable but lots of people buy Bilstein shocks.

 

[andyf]

This is what I recommend. 13 inch brakes, big tubular anti-sway bar, Koni shocks, Firm Feel upper arms, boxed lower arms and then play with the torsion bars until you get the right "feel". This combination will feel like a new sporty car when you drive it. Not a Porsche, but a new sporty car like a Charger GT or something like that.

 

[417guy]

This is what I recommend. 13 inch brakes, big tubular anti-sway bar, Koni shocks, Firm Feel upper arms, boxed lower arms and then play with the torsion bars until you get the right "feel". This combination will feel like a new sporty car when you drive it. Not a Porsche, but a new sporty car like a Charger GT or something like that.
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Andyf, Thanks so much for this input . My car is OE torsion bars, and front sway, no rear sway, KYB shocks, 11.75 front brakes with wilwood 4 piston calipers. It stops what I feel is very good. (11” rear drums). I truly appreciate the advice. What size front bar do you think I should start with ? Thanks again !

 

[andyf]

I wouldn't change the torsion bars. Put a big anti-sway bar on there and buy good shocks. Koni or Bilstein. For sway bar look at Firm Feel, Helwig or Hotchkis. I'd recommend a 1.25 diameter tubular bar.

 

[417guy]

I wouldn't change the torsion bars. Put a big anti-sway bar on there and buy good shocks. Koni or Bilstein. For sway bar look at Firm Feel, Helwig or Hotchkis. I'd recommend a 1.25 diameter tubular bar.

Thanks much ! I’m shopping right away for my parts for Christmas !

 

[andyf]

Do a google search on "big bar soft spring" and you'll find some interesting material. It isn't the solution for everything but big bar soft spring tends to work better than "small bar stiff springs".

 

[Nate S]

Do a google search on "big bar soft spring" and you'll find some interesting material. It isn't the solution for everything but big bar soft spring tends to work better than "small bar stiff springs".

There's certainly a balance to be had. In the general scheme of things you want each individual wheel to be squishy so it can take a pot hole or bump but don't want the car to tip. Big bar soft springs does this but the car is capable of tipping fore and aft too, not just left-right. Going too far this way allows the car to nose dive upon braking (or let's the nose go up for weight transfer when drag racing) and generally isn't a positive in a car wanted for handling. Stiff springs, especially with big rims and low profile tires can easily go the other way too, if you drive on fresh smooth pavement always I guess it can be ok but if there are bumps and such the car is likely to skid across them. Also takes more energy to move the whole car than it does to just squish the tire.

This is just a part of it though. Front and rear need both balance and proper geometry. Changing the ride height of the car can affect this negatively. Most common example is rear suspension height. Flat springs, when the car leans, steer the rear wheels inward slightly which is what you want. Arched springs (buggies, super stock, air shocks) steer the rear end outwards when the car leans, this leads to oversteer which is great if you're doing donuts but not so good on the road. Front geometry has details too, lowering it changes the angles of the tie rods, altering alignment through corners, also alters changes in camber as the car tips. Then don't forget balance, big fat stuff up front with stock springs in the rear throws this off.

Many cars have been set up with a mish mash of "suspension improvements" that ultimately won't make it down a twisty, bumpy road as fast as a stock setup (with better wheels/tires). Be careful as you do it and changes of rate >15% should get matching changes in other portions of the car.