EP 914-6 How low can I go? Options

[neilca]

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I am setting up an EP 914-6 for SCCA regionals. I have 22mm front torsion bars and 350# springs in the rear. How low can I set the ride height? I have found the bolts that hold in the front sub frame to be the lowest point of the car and I can adjust the bars till it hits the ground. The rear I use the jack points on the back corners of the tub. I can lower these down to 2" off the ground.

I have a set of the 23mm front bars also and can get heavier rear springs if needed. Any suggestions? I am runing cantilevered slicks from Goodyear.

I will be running tracks like Road Atlanta, Barber, Roebling and CMP. How low can I go?

Thanks,
neilca.

[neilca]

Thanks for all the feedback. My car is far from stock. I have:

Lengthened the lower control arms 2 inches, then changed the strut angle to compensate, which gives me one degree of negative chamber per inch of bounce. This also allowed me to tuck the ball joint into the wheel so I have almost a zero scrub radius. I spent a lot of time fixing the bump steer from all these mods, but I got it down to 0.03 through the entire arc. The inserts are Bilsteins for a Scirocco. These are a lot shorter than the 914 inserts. I made my own sway bar from 0.080 wall 4130 1.25 in diameter. It mounts in the usual place.

The rear upper mount has been raised and I use a set of aluminum Pro shocks. The engine was raised in the chassis in order to improve the driveshaft angle when the car is lowered.

The car weighs about 1800# with the driver.

Any suggestions on spring rates or shock travel?

neil

[stewteral]

Thanks for all the feedback. My car is far from stock. I have:

Lengthened the lower control arms 2 inches, then changed the strut angle to compensate, which gives me one degree of negative chamber per inch of bounce. This also allowed me to tuck the ball joint into the wheel so I have almost a zero scrub radius. I spent a lot of time fixing the bump steer from all these mods, but I got it down to 0.03 through the entire arc. The inserts are Bilsteins for a Scirocco. These are a lot shorter than the 914 inserts. I made my own sway bar from 0.080 wall 4130 1.25 in diameter. It mounts in the usual place.

The rear upper mount has been raised and I use a set of aluminum Pro shocks. The engine was raised in the chassis in order to improve the driveshaft angle when the car is lowered.

The car weighs about 1800# with the driver.

Any suggestions on spring rates or shock travel?

neil

Hey Neil,

Wow, a lot of work and a lot of mods on your car....so we have a whole new story on the ride height issue. While the REAR, with the moved pick-up points, may be lowered quite a bit....you will still be limited to lowering the front NO more than the range that keeps the lower arm parallel to the ground. Of course, it's your call here.

I am interested in the extension of the front suspension arms what the gains you.
However, in so doing you have SOFTENED the torsion bar & swaybar rates. Please review my attached Excel spreadsheet that calculates Front torsion bar rates, swaybar rates, rear coil spring rates and the resultant WHEEL RATES.

Of note is that the FRONT 22mm torsion bar with STOCK arms yields as Wheel Rate of 153.75 lb/in while lengthening the arms (assuming the same swaybar load point) REDUCES the Wheel Rate to 117.72 lb/in.

The input from the other EP racer is very interesting and helps you to have a "starting point", but my sense is that you may want to go Softer in the REAR or choose a STIFFER torsion bar rate. As recommended, the softer you can go, the better....so I would suggest the lower cost approach of balancing the car by SOFTENING the rear springs. Summit Racing sells them at $37.88 ea. in 25 lb intervals.....what is not to like?

If the attachment doesn't come through, just email me: porshepiloto914@verizon.net.

BTW: My apology from my last email, I've am use to thinking of the 411 engined 914s as EP and meant no "slight" about your 6 cyl car. I would choose the 911 engine over the VW every time........if I din't git  914_Project____EP_Spring___Wheel_Rates.xls ( 30k ) Number of downloads: 234
me some Chivy!! (IMG:style_emoticons/default/smile.gif)

BTW2: I have made BOTH of my swaybars the same way and have found them to work great: low cost and easy to mod as needed....way to go!! FYI: for my rear bar I was able to use SUMMIT RACING poly-bushing swaybar brackets (With Zerk fittings) for only $17/set....to easy!

Best,
Terry