DrDyno

Call Jason. No one here can shed any light on your thread count.

ghoastrider1

pologreen1

Pulling the front against the back won't stop something from twisting left to right. (might? help) IF the were affixed in several points it may help better. As pointed out above notice one of the frame improvements on the c5 the engineers did was connect left to right.

This is an aftermarket piece and some will say it works some won't some cases it may depending on application. The only real test is on each car. Is it possible your car was hit at some point? Just trying to think what would be the difference between your car and others. UNLESS not all the bars are created equal which is a quality control issue. Good luck.

Tom400CFI

No.

They DID use Balsa wood, sandwiched in composite for the floors in the C5 and C6, but that wasn't for structural rigidity...it was b/c is was light, insulated sound and heat out, and it was cheap. The rigidity came from a fully boxed central tunnel that tied the front and rear or the car together, and one piece rocker/frame rails w/no spot welds.

1984Z51auto

I have a set of these bars installed on a 1996 Convertible, replacing the "X" brace. The instructions give an "option" for mounting the rear suspension tie plates. These are the mounts that bolt between the rear trailing arm brackets and the body. One can use only the existing suspension trailing arm bracket mounting bolt or drill through the portion of the vertical pinch welded seam that runs the length of the rocker panel and add another bolt to strengthen the attachment.

I didn't drive the car with only the single suspension mounting bolt but, with both bolts fastened and the bars at 4 1/2 threads showing, the convertible is stiffer than with the stock "X" brace installed and a cowl shake/rattle that I couldn't get rid of before is gone. I am happy with the bars.

The only down side I see is that the bars block the stock jack points.

DrDyno

I've jacked the car up using the brace mounts... no problem!

1984Z51auto

I considered using the mounts as jack points but have not tried it yet. I've been using the differential adaptor on a floor jack and the front cross member with a floor jack to lift it. Did you see any sign of bending or over stress using the mounts?

DrDyno

I've placed my jack so it contacts the mounts rather than the rods or heim joints without seeing any flexure. If you're still unsure, contact Jason at Vette2Vette.

ovrebo1

Grade 5 bolts huh?

1984Z51auto

Thanks. Good, if you haven't had anything bend then it should work for the rest of us also.

dizwiz24

Lol. Agreed.

It does all this compression and only requires grade 5 bolts

AustinJohn

As some of you may know from other threads I was an early adopter of the No Flex System and the result before and after the system was installed and adjusted (which took some time) was night and day both with the top on and off.

Of all the posts in various threads I suggest MavsAK's on August 21, 2015 (Post #21 above) is a gem in explaining both how the system was envisioned and how it will and won't work depending on its adjustment. I would ask if there isn't one other factor that is critically important.

I am not an engineer but would ask if it isn't more important than having the the same number of threads on both sides to rather have both rods torqued the same. It appears to me that following MavsAK's explanation failing to do so will result in the main frame members reacting fundamentally differently and perhaps even amplifying problems rather than eliminating them.

I would welcome any thoughts.

John

DrDyno

Relative to torquing the frame braces equally, I would agree with your idea and, guess the tightening of the bars to equal lengths was the easiest way to accomplish this for the masses. I suppose the reason for "equal threads" is so you can have a way to keep track of your adjustments.

As I think back on my conversations with Jason, I assumed when he said "equal threads fore and aft," he meant both sides. Maybe he meant each side individually! However, I doubt that... doubt if any of us are that much "in tune" with our cars to notice different nuances, side to side.

I'll send Jason an email asking these questions and post his reply.

DrDyno

Following is the email I sent to Jason:

Hi Jason,

Yet another thread has popped up in the the C4 section of Corvette Forum regarding your Killebrew frame braces. I offered to contact you and post your reply.

The question was raised, "if each side of the car is set to the same thread count, how do you know both frame rails are equally torqued [tensioned]? Wouldn't it be better to torque the frame braces individually to know both sides are torqued equally?"

My response was I didn't know how that could be done and that the "thread count" was probably the easiest to accomplish for the masses. I also offered that when in conversation with you previously, I never thought to ask if "equal threads fore and aft" meant the same thread count for both sides. I just assumed it did. That is what you meant, yes?

Many thanks for giving our collective questions your thoughts and answers. I'll post your reply to this inquiry in the appropriate Corvette Forum thread.

Regards,

John

AustinJohn

Thanks for the reply, John, and especially for catching that MavsAK's post is #19 and not #21. Thanks also for emailing Jason; I look forward to his response.

Here's a little elaboration on why I focus on torque rather than thread count. As several posters have suggested the amount of pre-loading that works best on an individual car depends on various factors including not only mileage and condition of the car but probably the day of the week the frame was fabricated.

I've tried various amounts of pre-loading but one that works for me is 70ft/lbs of pre-loading on the passenger side rod which I've found is my most critical side. However, if I adjust both sides to the same thread count, I get 70ft/lbs of pre-loading on the passenger side rod but 100ft/lbs on the driver side rod, an unequal pre-loading and unequal pre-loading - in my experience of adjusting for maximum benefits from the No Flex System - leads to additional problems rather than benefits. Thus my goal is similar pre-loading on both sides but not identical thread counts.

As the No Flex System was never a part of the C4 design I've seen little discussion of the concepts involved (MavsAK's post is one of the few) but Chapter 10: "Handling Dynamics and Active Safety in the Corvette" of Dave McClelland's Corvette From the Inside discusses some of them.

John

DrDyno

How do you measure the torque? I'd very much like to be able to do that.

AustinJohn

I use a 1/2" drive Harbor Freight torque wrench (although their 3/8" drive will go to 80ft/lbs), a 1/2" to 3/8" adapter and a 3/8" drive 7/8" crowfoot flat wrench. I've heard the offset may result in a slight inaccuracy in the measurement but I'm after an approximation rather than trying to be exact.

Then set the wrench for say 70ft/lbs, give it a partial turn, and if it "clicks", you're at 70ft/lbs or above. If no "click", lower to 60ft/lbs and try again, and if no "click", 50ft/lbs and so on until you find where you are and then move to the other side.

I should emphasize again that my choice of 70ft/lbs is what works for me and not a suggestion for others. My guess is Dave McClelland (or Gordon Killebrew) might have a suggestion but on those occasions I've been with them, I never thought to ask. I will say that Gordon put my car through it's paces at a C4 Gathering several years ago after I installed the No Flex System and was quite complimentary. John

PLRX

I see a lot of disagreements between members on this one. This crap has become the new "opti threads"

Well, let's do this. If you have the money to "spare" and buy these bars knock yourself out.

I drove the bejesus out of my 1992 Vert, and Betty Boop (95), drive the bejesus with extreme prejudice out of The Ghost, and I don't have them.

Bryan had a racer C4 with 500 HP+, and he didn't have them.

Many others in here that actually drive their C4s don't have them.

If you want a stiffer car buy a Jeep.

DrDyno

So John... you use the 7/8 open end at the end of the black bar, itself? If so, how do you then attach it to your 1/2" torque wrench?

I can't picture what you're doing.

Thanks!

ColaBear

Use one of these on the end of the torque wrench.