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looking for strut bar data points

Posted: Sat May 21, 2022 4:01 pm
by maddog2020
I'm looking to get a range of measurements on the strut bar bolt down points. I know the fronts are closer together than the rear ones. can anyone measure theirs and so we can see a range of them? I'm having a custom strut bar made and there might be some interest later so the guy making them wants to make a jig.

best case would be a car that is on the ground and been on the road without being lifted for a while.

anyone? the more we can get the more exact he can be on his jigs.

Re: looking for strut bar data points

Posted: Sat May 21, 2022 7:45 pm
by Adamant1971
Just give him a strut bar to match the dimensions.

Re: looking for strut bar data points

Posted: Sat May 21, 2022 8:25 pm
by maddog2020
Did that. He wants to make the slots as small as possible

Re: looking for strut bar data points

Posted: Sat May 21, 2022 9:15 pm
by worf
maddog2020 wrote: Sat May 21, 2022 8:25 pm Did that. He wants to make the slots as small as possible
Your idea(*) is good. His idea is bad.

The variance of the hand-made unibodies of the fleet is such that even the OE strut bar can't always be bolted down with all four bolts until the suspension is pulled down.

If he makes the holes as small as possible then there are some - possibly many - 928s out there that won't be able to use it.

(*) Gathering data is a useful approach. With enough data and some basic statistical analysis you could determine the probable variance. However, you also have to factor in measurement noise from 10, 50 or 100 people measuring with their own tools, process and procedural errors.

If this was a betting game, guess what entity I'd bet on having done some of that math? One guess only.

Or, in other words, measure several OE bars and determine the probable variance and choose a hole size that gets you 2-sigma based upon the bar, not the body.

My $0.0928 -^

BTW, this problem of making holes too small rather than replicating the factory piece is why(**) the metal belly pan from Roger doesn't work while the metal belly pan from Mark does.

(**) One of the reasons.

Re: looking for strut bar data points

Posted: Sat May 21, 2022 10:03 pm
by maddog2020
oh I know. I requested that he duplicate the mounting points and explained to him that the mounting point spreads based on lifting, and other variables.

Re: looking for strut bar data points

Posted: Sun Jun 19, 2022 11:20 am
by maddog2020
so I ended up getting a 6 different measurements at the last breakfast. I was surprised how close they all were. just for future reference the 928 spreads 5mm when you remove the strut bar on a car that is lifted.

Front holes are 77cm and the rears are 77.5cm

I got my strut bar done and it fits perfectly and will clear the itb's. best of all it will look great ! I chose aero tubing profile, because I liked the way it looked, and also one of Mark Anderson's early strut bars used it.

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off to the powder coating shop next for a nice gloss black finish (along with a few other brackets) This year I've had the rear lower control arms modded and coated, as well as all of the engine support, motor mount and front tow hook brackets. been wanting to do all of that for a while.

Re: looking for strut bar data points

Posted: Sun Jun 19, 2022 2:12 pm
by worf
maddog2020 wrote: Sun Jun 19, 2022 11:20 am just for future reference the 928 spreads 5mm when you remove the strut bar on a car that is lifted.
Varies from car to car. Also depends upon how level is the lift.

Also true that some won’t “return” until the suspension is settled.

And, these insights also describe when you should do final hood alignment.

Re: looking for strut bar data points

Posted: Fri Jul 08, 2022 10:54 am
by maddog2020
Finished product. And it easily bolts on when the car is up on jack stands.

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