C4 No Flex Kit and C4 Beam Plates

[Jim Stanley]

I am considering installing the following in my '90
1) C4 No Flex frame kit by Vette2Vette and
2) C4 Beam Plates by Bill Bourdeau.
Please comment on your experience with these products including ease of installation.
Thanks,
Jim

[EvanZR1]

I don't have the No Flex frame kit, but I keep eyeing it. I do have C4 beam plates that Pete installed for me when doing the engine. The car did feel a little "tighter" after the beam plates, but it wasn't horrible before. I don't ever take my top off, so honestly the car doesn't feel too bad for being a almost a 30 year old car. If I was going to do any track days with the car, I'd probably be more motivated to do the no flex frame kit, but then I'd also be looking at doing a roll bar and better coilovers.

[secondchance]

In my opinion, beam plates help with tying engine/trans to rear differential. This in turn, theoretically reduces torquing of the body.

I do not have No Flex kit and have no comment.

[Karl]

The beam plates just help the car track in a straight line under hard acceleration and prevent the rear end from kicking out sideways.

I have the exotic muscle 4point bar in my Z. Mainly for the camera mount and extra stiffness.

I rode in -=Jeff=- Z with the no flex kit and it is a day and night difference with and without it. Especially over uneven roads etc.

Well worth the investment.

Good luck.

[dredgeguy]

I have both and they do the job. The C beam plates are night and day if you decide to go to the drag strip. Without the plates, the rear of the car would pull left if the rear tires broke loose. With the plates, she stays straight. As Secondchance said, keeps everything together. The No Flex does that even more so. There is a dip in the road near my house and if I had the roof off, the body would flex going over the dip and the glass top locked in place in the rear would creek and moan. Thought the plastic would shatter it was so loud. After installing the No Flex, no more noise so that is proof enough for me. I was lucky, the No Flex was one of the silent auction items at the ZR-1 Net Registry tent at Carlisle a few years ago and I got a great deal on it.

[Jim Stanley]

Thanks to all for your helpful feedback. I now know how to proceed. I am going to go with the V2V No Flex first as I don't race the car.
Best to all you Zroners!
Jim

[billschroeder5842]

Thanks to all for your helpful feedback. I now know how to proceed. I am going to go with the V2V No Flex first as I don't race the car.
Best to all you Zroners!
Jim

Good for you. I put on the V2V kit a few months ago and am very happy. It really quieted the car as well as making it feel a little more solid.

[-=Jeff=-]

I don't race my car either and I have both.. In fact I still have the prototype No flex bars on my car.. 10 years with no issues. I was amazed on how quickly I noticed the difference in the car after getting them

[dredgeguy]

While I found a big difference in the way the car handles with the C Beam Plates, I have only taken my car on the 1/4 track twice, once without the plates and once with the upgrade installed. That is where I found a big difference.

[Dynomite]

1. Advantages of C4 Beam Plates.
a. The C4 Beam Plates tie together each pair of bolts (Transmisison pair and Differential pair) with a SS Plate vice aluminum.
b. Each C4 Beam Plate also offers a larger contact area of the tensile bolt loads onto the C-Frame. This eliminates the wear on the "C" Frame from a smaller original washer and resulting release of bolt tension.
c. The C4 Beam Plate also acts like one big washer wherein the tensile load from each individual bolt is now shared a bit between bolts (minimum effect).
d. The C4 Beam Plates correct the condition caused by the bolt holes in the Aluminum C-Frame getting bigger or elongated with wear or the thickness of the Aluminum C-Frame from top to bottom between the original bolt two washers becoming worn so that thickness is less releasing bolt tension.
The C4 Beam Plates are definitley worth it if only for the Bolt Load Distribution (Two BIG SS washers on each end) on the C Frame and Ease of Installation. Take Note of the additional Stiffeners on each C4 Beam Plate (The BIG H). There is a BIG Difference between a Clamping Load distibution by two washers and the Clamping Load on ONE BIG PLATE on the Transmission Yoke as well as the Differential Housing.

Post 39 - C4 Beam Plates and Installation (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-2.html#post1581480716)

[Karl]

You can see at the 14 second mark the rear end kick out to the right.

https://www.youtube.com/watch?v=3ZrNvJxDD-0

[XfireZ51]

Have had beam plates since my 84. They really do help car track straight.
Installed the V2V No Flex 2 years ago and you can immediately tellthe difference. When u go over a set of RxR tracks, you just hear the initial thud, then nothing. No secondary vibrations or buzzes. With top off, it does not completely eliminate W/S header shake.
Both highly recommended. While ur at it, go for the DRM trailing arm and rear tie rod brackets.

[Paul Workman]

Well, FIRST let me say that I do have Bill's beam plates and if nothing else, if ever you need to remove/reinstall the C-beam for any reason, you will bless the day you installed them for ease of completing that little chore - especially if you have average to large hands (which apparently, I do!): worth every penny if they did nothing else! And, as Cliff pointed out, they disburse the clamping forces over a wider area so "cold flowing" (squishing) of the soft aluminum does not result in releasing the clamping force that secures the joints (evident by the shifter raising up, among other ills, under hard acceleration).

That said, when considering the long lateral "bat-wing" mounts on the differential, AND the fact the rear wheels are independent of the differential by virtue of the U-joints on the short shafts, it puzzles me still just how the stiffening of the C-beam tie points improves the straight-line acceleration? Maybe (and this is just a hunch) the frame has a tendency to flex (twist laterally) thus (by virtue of orientating the angle of the bat-wings) pointing the rear wheels to one side...were it not for a secure attachment of the C-beam assisting to counter lateral twisting? And, if so, perhaps the stiffening bars would resolve that issue as well??

I have the C-beam plates. Love 'em. But, I never take the top off, and even after going 'airborne' a few feet and crunching the front bumper, the car does not squeak n creak like some say theirs do. I don't know why not mine? Could it be some cars joints are looser maybe? Or is it a phenomenon limited primarily to the top being off (which -=Jeff=- often does)?

Having never experienced a car w/ the no flex bars, I cannot speak to their effectiveness on a car with the top in place. And, maybe the elongation of the bolt holes in the C-beam over time is telling us that the poor C-beam is being forced to bear the burden of the frame that would otherwise be flexing w/o the added support of the C-beam? Just a hunch. But, in any case mine with the C-beam plates installed doesn't seem to squeak - come whatever the road can dish out.

I'd try the C-beam plates first before installing the bars to see it the C-beam plates do the trick, that is as long as the top is not removed. Cams and gears have risen to the top of my "to do" list, over no-flex bars (at present).