DIY Chassis Torsional Rigidity Testing, The Results Are Strong!

All the chassis modifications to my Porsche 911 are now complete. In this episode I show you how to try DIY chassis rigidity testing in your home garage if you want. The results aren't bad, and I can't wait the get the car on the road and doing more driving tests.
Thanks again for watching.
T shirts available on
www.ahhgaragetime.com
This video series filmed in my home workshop highlights the technical details of my classic car restoration (An aircooled Porsche 911). I’m starting with a stripped out shell from 1974 and backdating it to the earlier longhood look. (Backdated Porsche means to make it look older than it is). It’s not easy to build a car in a small garage but I hope to inspire other gearhead minded people like me to build something cool with DIY style.
In the first few episodes I will focus on the autobody metalwork to transform this junker into something fun to drive. Extensive metal fabrication is needed to give the body the wide and low stance that I'm looking for. Metal fab can be time consuming but its the detail that set each car project build apart from the rest. My classic Porsche strives to be unique with custom hotrod touches throughout. There will be some rust repair in the front trunk area including the infamous suspension pan...home fab style.
I plan to update weekly videos detailing the customization of my classic sports car. This is a low budget build so I plan to make many of the custom parts myself wherever possible. I hope you enjoy my car vlog that will hopefully become an autocross racer or track car someday.
Engine plans are 3.0L+ with individual throttle bodies ITB
Custom brakes and suspensions mods are also planned.
Please stay tuned for all updates on this project series.
Product and tools info at www.ahhgaragetime.com
My Classic Car Restoration Future Plans
I plan to modify the suspension and brakes with improved aftermarket parts from Elephant Racing and Tarett Engineering as money and time allows. Larger brakes from a late model Boxster will be used since this car didn’t come with any brakes and they seem to be the best bang for the buck. The engine will be from a later Porsche 911 to with at least 3.0 liters and I hope to use a custom individual throttle bodies with a modern injection system and software.
In other words, this build will be a mashup of all Porsche’s best years. The classic look of the early lightweight body with a more modern air-cooled drivetrain. Call it a restomod or hotrod if you like, but I’m going to make it my own with custom touches along the way. Please join me in this detailed restoration journey.
Porsche...there is no substitute
Visit my website at www.ahhgaragetime.com or
facebook at ahhgaragetime
Instagram at ahhgaragetime
Here’s a recommended book.
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[@grantroberts4231]

haha! lucky guesses. great vid. happy sanding.

[@GarageTimeAutoResto]

Thanks Grant. I'd rather pay you to play Roulette in Vegas than sand!

[@Dave_Boyer]

Way to go Grant! He was on the money! I thought it would have tightened it up more, but that’s a good engineering lesson for the day!

[@GarageTimeAutoResto]

I too was more optimistic, but it's hard to argue with data! Thanks for watching!

[@carl545marchbanks4]

Thanks for sharing. You won't find this kind of information anywhere else!

[@GarageTimeAutoResto]

Thanks, I'm glad you liked it.

[@mddoc124]

Really enjoyed the engineer videos

[@GarageTimeAutoResto]

Thanks Doc!

[@mikeemery3962]

Garage Time - Restomod Hi Tom Probably not quite on the radar yet and you may have already looked at these types of products.. but right up your line of thoughts I would imagine to increase rigidity are these products from Wevo. I am sure others may produce something but with your skills and adaptive techniques I am sure you could fabricate something along a similar vein! www.twinsparkracing.com/product-category/shop-by-parts/transmission-gearbox-porsche-911/engine-mounts/

[@GarageTimeAutoResto]

@@mikeemery3962 Yes, I love all that stuff too. At the moment I'm laser focused on getting this car painted, but I will be experimenting with suspension bushings and trans/motor mounts in the future for sure. The current game plan is get the car drivable first and then continue to optimise and tinker with this kind of stuff. Of course I look forward to reviewing the before and after results.

[@mikeemery3962]

Well done Tom another major milestone.. no more fabrication! Just think of the sanding as the penultimate step to showcase all your hard work.. put on some good music and the time will go quickly..

[@GarageTimeAutoResto]

Thanks Mike. Yes! Led Zeppelin should get it done!

[@DoubleRRestorations]

It looks great Tom. This next phase will be my favorite. I love seeing the project come to life by adding the finishing touches. I wish we lived closer. I would help you with the sanding.

[@GarageTimeAutoResto]

Thanks Russ! Yeah, just hop in that Camaro and stop by during your lunch hour.

[@roundtailrestoration]

Engineering kicks ass, Tom. Good job. I have no experience in that kind of stuff, but I'm sure you'll notice a difference with those numbers!

[@GarageTimeAutoResto]

Thank you Chris. I hope so.... I'm anxious to drive it and compare with other cars. I do feel like I've done my best and now it's time to move on.

[@thebandit4393]

Great work! Awesome to see a little engineering at work.

[@GarageTimeAutoResto]

Thx, I love the techy stuff😀

[@brianmackenzie4265]

Tom looking at now and watching the test it gonna be awesome when finished. All the mods will pay off..

[@GarageTimeAutoResto]

Thanks Brian! I'm behind schedule but it's coming out nicer than I thought it would! This reminds me of the fast, cheap, quality triangle. I'm definitely trying for cheap and quality. Pick only two which is why I'm behind.

[@brianmackenzie4265]

@@GarageTimeAutoResto Tom its gonna be cool to see a finished body shell in the corner. The motor and gearbox that you build will be new and exciting chapter. Cheers ...

[@jaymckoskey25]

Very interesting results. I expected the door bars to do more also. Some of the torsional elasticity you measured may have been forward of the front suspension load support inputs, which would be of no consequence to handling. You can apply the torque at or outboard of the suspension inputs but it seems to me that the measurements should be at the suspension inputs plus, perhaps, some intermediate points if you want to identify the positions of greatest deflection. You probably should also not use the torque arm as the measuring arm since it too can deflect and show up on the dial indicator.

[@GarageTimeAutoResto]

You are right that torsional bending in front of the suspension cross member probably doesn't affect handling much. I measured deflection at the forward most suspension pickups but most of the cornering loads are at the rear suspension pickup. My goal was to measure chassis stiffness before and after welding/bars without too much setup effort. For instance, I didn't feel like removing the front A arms, wheels, etc. I was mostly interested in percent improvement, but as you say more measurement points would provide more interesting data. I even considered mounting strain guages to the passenger footwell and door opening. The torque arm did bend, but the applied torque is the same whether the arm bends or not. The dial indicator was placed directly under the chassis attachment location so no bending of the arm can occur there at the beam supports. While there is room for improvement in this data, the truth is there isn't much of anything out there. So hopefully this will spur others to think and measure more!

[@rustedhorsepower5132]

Awesome work Tom, pretty cool. Hadn't watched for a while, but as I see, tons of work has been done, GREAT job! I had a bit of drama in my life, made a video "take this job and shove it" , long story short, I daily drive my chevelle now.

[@GarageTimeAutoResto]

Oh, I'll check out that video. Hope your new chapter turns out the way want!

[@futurenewmedia]

That’s a significant increase in torsional rigidity almost double what I expected from the start, you’ve got to be well pleased with the results 👍 is there a reason you didn’t install your front turret brace and diagonal prior to testing ... that my well take the improvements beyond 15%. Great job Tom 👌 P.S. I’m liking the whole deviated bumper colours going on there in the current grey and white mix... got me thinking about silver, maroon or British racing green with the Bahama yellow... it’s a hard job watching you do all this work ya know 🤪😂

[@GarageTimeAutoResto]

Yes you are right Mark. This is nothing to be ashamed about. And you have a good eye! I knew someone would ask about the missing turret brace. That bar was cut to add the transducer in the middle and I had to borrow that equipment for a different project. So rather than weld it solid again, I just used the "without bar" data for comparison. When I fabricate the actual brace I will include double diagonals for even more stiffness. I think the single diagonal was 5-8% improvement. So with the seam welding, strut bar, and cage I'll be over 25%. 👍 I would love to test a 964 or 993 someday for comparison. I have also been liking the two tone look. Might consider a grey/silver with a stripe on the side? Might be something I'll add later??? Thank you for watching. Are you racing that 993 yet?

[@Dogleg1957]

Try testing a front strut tower bar's effect on unibody ridgetity

[@GarageTimeAutoResto]

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[@Dogleg1957]

@@GarageTimeAutoResto thx! Going to fix cup of bailey's n coffee and watch this video

[@KenKroslowitz]

That's probably one of the most noticeable handling improvements that can be made.

[@GarageTimeAutoResto]

Really how so?

[@KenKroslowitz]

@@GarageTimeAutoResto my comment may have been premature, as i hadn't seen the strut bar test video, and now realize that the stress loads are different between coilovers and a torsion bar suspension. I did install a cheap strut bar on an e36 m3, and was surprised by the difference during turns extreme enough to trigger the dsc. I plan on installing them on my Cayman project car.

[@R0yL33]

Looks like a pretty beefy bar but how much of the deflection is in the bar itself ?

[@GarageTimeAutoResto]

The bar does deflect, but not at the point where the deflection is measured. The dial indicator was placed strategically to eliminate this effect.

[@lilPOPjim]

I think the test set up is wrong. As you are supporting the chassis on 3 corners, you have the weight on the unsupported corner already preloading the chassis before the test. I don't know how much that car weighs but you could easily have 200kg on that corner weighing it down, and flexing it before you even start applying your own torsional load. You should be supporting the chassis at the front, directly in the middle of that bar, with a semi sharp/blunt supporting member so that the body can freely rotate around it.

[@GarageTimeAutoResto]

What you are suggesting would be better, but it would be harder to twist the chassis with body weight.. Chassis stiffness is measured in rate of twist Torque/deg. Rates are constant, so it doesn't matter if there is a small offset load in the beginning. For example you can measure the rate of a linear spring anywhere within its travel. I said that I was only interested in the relative improvement of my changes. This setup is totally valid for seeing percent change.

[@schuttrostig5729]

now weld in some door bars and see how much that is......

[@GarageTimeAutoResto]

Yeah, but the hard part is unwelding them.

[@andremarais2706]

A 912 engine will warp this chassis out of whack. Lol.

[@GarageTimeAutoResto]

Maybe I should put one in the front and back for all wheel drive?

[@andremarais2706]

@@GarageTimeAutoResto That 2.7 or 3.0 or 3.2 engine will be there before you know it. Very talented. Blessings.