What do you have for chassis stiffening? Options

[Justinp71]

Well my conclusion for my more street oriented car.




Miesto, Drum Roll Please...





GT rear kit and the Brad Mayeur Long kit!
(and probably CFR's inner trailing arm support too!)


Anyone else want to share, what they have???

[IronHillRestorations]

I forgot to add that I welded up all the seams I could. TIG where possible, and MIG everywhere else.

[Justinp71]

Did you race or a/x the car that you are describing?

[IronHillRestorations]

The customer that I built the car for did autocross, time trials, and track events.

[Justinp71]

No cage, correct?

[charliew]

What makes these little cars attractive is their light weight. But the power levels when they were designed was lower and the tire tech has gotten so much better. The tricky thing is to only add as much support as is necessary to the exact weak spots that are known. This is where you originally started your quest. You seem to be off to a good start as the some of the smart guys have already assisted you a lot.

I would bet that in a lot of cases the fractures started before the reinforcements were added. You know some of these cars started as just two or three times a year racers and then bigger and sticker rubber was added and then more power and so on till it got serious and the cracks started appearing so then the repairs and stiffening started where it was obviously needed but then that moved the stress to the next weakest area and so on. If you start out knowing what the bad areas are and brace them before the stress is applied it will end up much better.
I know this is what you are doing and the reply about the cage tieing the cab up tight helped the long area a lot. The suspension ears are a problem all by themselves and need to be braced and thickened to spread the load out over a larger area.
I would like to do a permanent brace from the targa to the windshield but I don't think the windshield is strong enough as it is. I don't think there is enough room for a cage in a street car without wearing a helmet all the time. But that is the best bracing solution. Of course a exoskeleton would be the best but how stupid would that look on a street car.
I have lots of studying to do it seems.
The safest thing is to do the mods you listed and only run about 9 inch wide tires and keep the power below 250.
I find it hard to believe that these cars don't get real crooked on a rotisserie when the whole long is cut out on one side even with the diagonal brace that is used between the seat belt point and the kick panel.
I may persue the idea of a 1-1/4 tube cage that is tight up against the body at the windshield and targa and nothing overhead on the outside but two connecting tubes in the middle away from your head. This would not be as good as over the side windows but would be where maybe your head couldn't contact it in a wreck with the seatbelt on. I would also like to angle the windshield back some and that means a lower roof line but that might be asking too much.
I'm only 5'8" but both my sons are taller and they may want this car when I'm done with cars.
I have fieros and both my son's think they are too confining although I know some 6 footers with fieros.

These cars are very thin sheetmetal boxed sections and sometimes the spot welds are not as good as the engineers planned. Seam welding is the time proven helper on all unitized cars used in motorsports. I know the seam sealer is a pain but it might have come loose because of some of the twisting, where it's loose might give a indication of where the most twist is at stock levels.

[Simon Tibbett]

I am new to 914's and looking into getting one, and will be tracking it.

I never knew the chassis cracked easily. Is this common with hard driving and upgrading suspension?

[jt914-6]

I have Brad's long. kit, GT kit, boxed trailing arms, full cage (not tied into f or r) front and rear stiffening.

[jhadler]

In the first photo there, it looks like you are drawing heat for the passenger compartment off of the cooler in the front. Did I see that right? If so, I think it's brilliant!

-Josh2

[jt914-6]

Josh, yes I'm using the cooler heat for the winter. Hose from the cooler goes to a "T" and then to orignal heater hose connections. A friend tried it too with his and it works.
Run the hose from the cooler down under the old gas tank area and exit hot air under the car for summer. I have a two speed fan mounted to the cooler to pull out the hot air when needed. Using an Earl's 60 row cooler #26012. It is 7 X 19". Usually run 180 degrees and on the track in mid 70's temp around 200 degrees....

[J P Stein]

After bonking my helmeted haid on my cage halo, I cut it off and did this.
Tying in the suspension towers gave the best chassis stiffening effect of all I did.

[Joe Ricard]

JP would you please show me your engine lid?
Like a dumb ass I followed your design once again with the rear shock tower to cage thing. Now I need to made an engine lid. Probably out of fiberglass and wire FOD screen.

[J P Stein]

I don't have a pic of it, go figure.
I made a GT type lid then Brit notched it to clear the tubes. Stock mounting with Dzuts fasteners. I'll take a pic & get back to ya.

[Joe Ricard]

Metal?

My car will have bare minimum of metal. I am thinking of removing the targa and making a fake one out of FG. The cage will actually be the support for the super thin single layer FG roof skin. It might look like a 914 but it is nothing Porsche anymore.

[J P Stein]

Metal?

My car will have bare minimum of metal. I am thinking of removing the targa and making a fake one out of FG. The cage will actually be the support for the super thin single layer FG roof skin. It might look like a 914 but it is nothing Porsche anymore.

I'm done with adding lightness. My next project will be more grip.
XP is where I'll be.

[Joe Ricard]

Yea PM me with your thoughts.
I'm a looking at some 16 x 10 for the rear. I'll have more dough in rims and tires and shocks than the whole rest of the car.

[J P Stein]

Yea PM me with your thoughts.
I'm a looking at some 16 x 10 for the rear. I'll have more dough in rims and tires and shocks than the whole rest of the car.

I may have some wheels for you in a few weeks.

[Chris Hamilton]

Has anyone measured the amount of flex they had before and after the reinforcements?

[Britain Smith]

Didn't measure it, but we felt it in JP's car.

-Britain

[Joe Ricard]

I can 3 point lift my car and it stays level.
get a jack stand under each rear lift donut and then put a jack under either front donut. The front of the car comes up instantly with not measurable flex. Not the case in an un caged car.