I made a front strut bar as a possible Idea Factory product. After installation I measured the effect. For comparison purposes I also measured a OMP strut bar (BAT about $150) on Terry's car.
My bar is 1" square steel with 2 "bends" which were cut and welded. A gusset was installed on each bend. Angle iron was welded to make the strut top brackets. My bar mounts toward the rear of the upper intake. The bar mounts to the mounts with a single 1/4 bolt at each end.
The OMP bar is about 1.25 dia and made of Aluminum. It has 2 bends which are not gusseted. The strut top mount is cast Aluminum. The bar mounts on the forward of the upper intake. The bar mounts with a single 5/16 bolt at each end.
Test set up: A stiff bar was laid across the motor. For the first test the bar was clamped to the strut bolt and the dial indicator mounted to the other bolt. For the second test, one end was clamped to the strut tower, a dial indicator was mounted on the other strut tower. For each test the chassis deflection was measured with the bar installed and removed.
Test procedure: The dial indicator was "zeroed" and a 185 lb load was applied to the front bumper at the end. The test was repeated several times on each end. (Yes, sitting on the bumper causes measurable bending of the front of the chassis.)
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| no bar | bar | no bar | bar | ||
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85 Xr | .025 | .025 | .010 | .003 |
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85 Xr | .020 | .015 | .010 | .003 |
Notes :
1. The strut bolt moves more than the tower, this is due to the
rubber mount. On the OMP car, the rubber is quite old and feels
stock. On Slocum's car the rubber is 1 year old GpA. (they make
your teeth chatter) (.025 vs. .015)
2. Both cars have stiff struts and stiff springs.
3. Adding a strut bar cuts the chassis deflection quite well.
4. The OMP bar works, if you want better, solid mount the strut
and eliminate the rubber.
5. The 185 lb load is much less than cornering. A 1 G corner will
put an additional 750 lb. on the outside suspension.
6. You can really notice the feeling of the bar.
