Chassis flex issue...

[SummerSledSix]

Finally drove my teener with the top off for the first time since the six conversion. Have noticed what I think is a chassis flex when I go over rough pavement. It seems like the chassis is torsioning or twisting (ever so slightly) about an axis that runs down the centerline of the car.

Don't remember experiencing this during its 4-banger days, so I'm wondering if the Carrera suspension I put in up front might be responsible in some way, ie, more weight, stiffer torsion bars, shocks, etc.

Does any of this sound familiar to anyone? Putting the top back on tends to quiet this right down, so I'm suspecting flexible flyer syndrome. The pan and the rockers are rust free, I welded in the chassis reinforcement kit (nothing forward of the jack posts, tho).
I believe the PO AX'd the car somewhat, and I found (and welded)a crack in the longitudinal on the driver's side at the lower forward corner of the parking brake "dimple".

I've DE'd the car twice so far, and have experienced oversteer in a number of forms, tho that is at least partially due to my own lack of seat time.

Guess my options are 1, roll cage; 2, welded on top; 3, some kinda longitudinal reinforcement.

Any opinions / recommendations / creative solutions?

[Dave at Pelican Parts]

Opinions? Yeah, got those...

Brad Mayeur's "clamshell" kit (that we also sell) will probably help at least a bit. You might also consider a piece of square tubing across the floorpan at the firewall, though you'd have to deal with the holes for the various linkages and such. Another idea is a (smaller) square tube across the bottom of the rear window. Make sure those lateral braces are tied securely to the side structure of the car.

Other places that might help: Inside the front trunk, above where the front of the torsion bar tubes are. Across the rear of the front trunk, by where the rear mounts for the A-arms are.

A full cage tied into the suspension pick-up points would obviate most of that. If you don't go for the cage, consider at least the clamshells and possibly the rear window brace and front trunk brace. The trunk brace will help more if you have holes or rust in the front trunk, obviously...

--DD

[evill]

John, this is typical in a 914. It does flex more with more HP, stiffer suspension and sticky tires. I have the Brad Mayeur kit on my 914 and it stiffens it up significantly, I reccomend Brads kit for any performance 914. On the track I still have some flex, but that is from the 914's inherently weak windshield frame.

We install Safety Devices roll cages at the shop, these really stiffen up the 914. We usually weld tabs to connect the windshield frame to the front roll cage legs to stiffen it up. Without the tabs you can actually see the winshield frame move from side to side (if you stare at the roll cage legs) in hard turns.

With the cages, the tops usually do not squeak and rattle any more. Most of that is caused by the windshiled frame moving.

I will be adding one to my 914 this season.

Ed

[red-beard]

I was reading an article about the Brad Meyer kit and one of the things that was suggested was looking at the door alignment to get things straight before you install the long reinforcement.

Is this a good indication of flex? My driver's door is in good shape, but the passenger door is low.

In the short term I'm going to live with this, but in the long haul, I want this 914/6 to last. It sounds like the Brad Meyer kit would be a help. Would it also pay to install the other chassi stiffening kit?

Will these de-value the 914/6? I know I know, only worry about value if you're going to sell.....

I won't be doing this until I get the other 2 out of the shop!

James

[Dave at Pelican Parts]

I have the feeling that a chassis that is weak and sagging (usually from rust, BTW!) will devalue the car more than having the reinforcements properly installed...

--DD

[URY914]

A few years back I did a little test during a driver's ed at Road Atlanta. I took a long piece of masking tape and taped tightly between the rear shock towers before going out for a session. When I checked it when I came back in it had broken in the middle, but did not pull off the shock towers. I'm sure the factory uses a little more advanced test, but it indicated to me that there is more flex going on than you may realize.

I made a rod to go between the shock towers and attached it using u-bolts. It attached below the lip around the top of the tower. It was very simple but I did the tape test at the next DE and it didn't break the tape.

[John Rogers]

A six point cage, eith weld in or bolt in is about the only way to really stiffen the middle part of the car which also happens to be the weakest! Good luck.

[J P Stein]

As Mr. Rogers says, the weakest point of these cars is at the door openings....no big surprise there. The front section moves independly of the rear.....not good for suspension tuning or long term chassis life. Rust just makes it worse.

Jon Lowe (PCA 914 tech rep) has the bestest 914 web site in existence (IMO) but I have lost the link.....DD's prolly got it.

Lot'so stuff on chassis stiffening in there, including the WORD on the windshield support (or lack of it).

I did a 10 point cage but did not tie it into the windshield supports. I won't bore ya'll with more pics.
Also don't have the "Chassis stiffening kit", that is widely sold. As a "stand alone" modification, I question its effectiveness.

Brad Mayeur's clamshells seem worth while, at least at the rear of the doors, which is prolly the weakest area, the front is close second.

There is no easy way to fix this.
(Edit)

Lemme rephrase this last bit. Fixing this is a major league PITA.

[Dave at Pelican Parts]

The only Jon Lowe website I know of is his 914-6 GT page, which has tons of photos of the various factory (and some aftermarket) GT race cars.

http://home.hiwaay.net/~jonlowe/

--DD

[SummerSledSix]

Thanks, everybody, for the great tips. I've been to Jon Lowe's website before, but never realized each of those GT's have *multiple* pages of pix. The one on "my GT" seems to be the motherlode for reinforcement pix.

Looking at my teener again, it's no real surprise I found the crack I described if the PO was an AX hack. Also noticed I could see daylight between the front wheel well and the front bulkhead (and there's no rust there)! Guess Karmann was in a hurry to get my particular chassis out the door. Think I'll start with seam welding that stuff...

So Jon apparently started with a Safety Devices bolt in roll cage. Any opinions / war stories on this vendor vs another vendor vs custom shop made stuff? I have a welder; is this a good excuse to buy a tubing bender too?

[rdvnac]

James (aka red-beard):

To answer your question about chassis reinforcements affecting the value of a -6, I am fussier than most 914 buyers/owners about modifications, and I can tell you that when I was looking to buy a factory or conversion 6, if the seller said the car had the Brad Mayeur kit installed I considered it a "good thing," a plus in value.

I also know that if the CW factory 914-6 I just bought (leaves the west coast Monday, should finally be in my hands late next week, yippee!) has ANY issues, I will do the PP/Mayeur kit too.

HTH.

[Racer Chris]

Hi John,

I'm in northeast CT and fabricate custom welded roll cages. Check out my website www.tangerineracing.com , and email or call me. I'd be happy to discuss any aspects of 914 chassis stiffening with you. I can supply you with bent tubes if you plan to weld your own cage.