C4 FRAME TECH. Talk about frame specs and flex solutions...
07-21-2010, 10:54 PM
#121
Instructor
Member Since: Nov 2002
Location: clarendon hills il
Posts: 107
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The "cross-frame" brace and "camber" brace did a lot to improve my comfort level in my '91 coupe.
I always felt the rigidity of the cross-frame could be improved if the "floating," open center,one size fits all design was "fixed" while still allowing the easier two piece removal/install.
I ended up welding the bottom plate "cleat" to the other frame member and bolting the intersecting overlap together with a 7/16X2" grade 8 bolt.
Scientifically, I can't prove anything but without a lot of rhetoric, top off driving is a lot more relaxing and the car is very solid with the roof panel installed.
I always felt the rigidity of the cross-frame could be improved if the "floating," open center,one size fits all design was "fixed" while still allowing the easier two piece removal/install.
I ended up welding the bottom plate "cleat" to the other frame member and bolting the intersecting overlap together with a 7/16X2" grade 8 bolt.
Scientifically, I can't prove anything but without a lot of rhetoric, top off driving is a lot more relaxing and the car is very solid with the roof panel installed.
By the way, I saw you live in Westmont, I happen to live in Clarendon Hills, so you can likely relate to my recent targa top off driving experience. Basically I drove on 55th street from 355 to 83 with no top and I thought the steering was going to come off. Ok not exactly that bad, but bad enough where I vowed not to take off the targa again.
02-28-2016, 04:28 PM
#123
Safety Car
This is an old thread but wanted to bump it because there's a ton of great info in here. I'm sure many know of the car by now but there was a ZR-1 that dieline built and they reinforced that chassis significantly. I'll find the links to it.
Besides wanting to add that, I am in the design process of having some chromemoly welded into my ZR-1 and my 93 lt1 car. I'll add more to the thread when I can provide photos and info!
Besides wanting to add that, I am in the design process of having some chromemoly welded into my ZR-1 and my 93 lt1 car. I'll add more to the thread when I can provide photos and info!
The following 2 users liked this post by 5abivt:
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02-28-2016, 04:37 PM
#124
Team Owner
Pro Mechanic
Thread Starter
^Awesome! Can't wait to see details! 
06-15-2016, 06:28 AM
#125
Cruising
This is an old thread but wanted to bump it because there's a ton of great info in here. I'm sure many know of the car by now but there was a ZR-1 that dieline built and they reinforced that chassis significantly. I'll find the links to it.
Besides wanting to add that, I am in the design process of having some chromemoly welded into my ZR-1 and my 93 lt1 car. I'll add more to the thread when I can provide photos and info!
Besides wanting to add that, I am in the design process of having some chromemoly welded into my ZR-1 and my 93 lt1 car. I'll add more to the thread when I can provide photos and info!
06-15-2016, 01:05 PM
#126
Team Owner
Pro Mechanic
Thread Starter
06-15-2016, 03:54 PM
#128
Burning Brakes
5abivt was online today so I'm guessing he doesn't have a solution or hasn't tried his idea yet as he did not reply to this thread.
In addition I hate the look of a roll cage in a street car. It's my opinion but I don't like it. My 84' doesn't seem to have a bad column shimmy but you can definitely tell the difference when the top is off. It certainly feels like you lost some rigidity.
In addition I hate the look of a roll cage in a street car. It's my opinion but I don't like it. My 84' doesn't seem to have a bad column shimmy but you can definitely tell the difference when the top is off. It certainly feels like you lost some rigidity.
06-16-2016, 12:13 AM
#129
5abivt was online today so I'm guessing he doesn't have a solution or hasn't tried his idea yet as he did not reply to this thread.
In addition I hate the look of a roll cage in a street car. It's my opinion but I don't like it. My 84' doesn't seem to have a bad column shimmy but you can definitely tell the difference when the top is off. It certainly feels like you lost some rigidity.
In addition I hate the look of a roll cage in a street car. It's my opinion but I don't like it. My 84' doesn't seem to have a bad column shimmy but you can definitely tell the difference when the top is off. It certainly feels like you lost some rigidity.
https://www.corvetteforum.com/forums...new-twist.html
06-16-2016, 01:03 AM
#130
Safety Car
No updates on my end .. I haven't even started driving my ZR-1 yet this season 
still have a ways to go and then vacation to the end of the euro 16 but when I get back in July the Z should be on the road. I've spoken with my fabricator and he's on board so i will be heading over to him to do measurements and am discussing the options in person. 
still have a ways to go and then vacation to the end of the euro 16 but when I get back in July the Z should be on the road. I've spoken with my fabricator and he's on board so i will be heading over to him to do measurements and am discussing the options in person.
06-20-2016, 02:03 PM
#131
Melting Slicks
V2V Bars - My Impressions
This is long, so feel free to scan this message for the key points! I know there has been a lot of debate and speculation about these bars, and well, I am not going to help settle any of the arguments scientifically but wanted to give you my thoughts on them.
I never had any intentions of buying a new set for $499 + shipping. I found a guy on ebay selling a pair and won them for a good price.
-They installed easily and were extremely well made. So much so that I would go as far as saying that it was the easiest aftermarket part install I have ever done. There was no modifying or fuss involved (Aside from parking brake cable, will get to that). 30 Minutes and they were on! Ground clearance was not changed and the ZF still was the lowest point on the underbody.
-I noticed an immediate difference in how the car drove. Did it handle better? Not sure...Was the car more stable? Sure felt like it. It felt like the suspension may have been doing more of the work than the frame. There were less interior creeks, but my interior is pretty sorted out to begin with. I can't say for sure it helped with driver confidence in the corners or anything, but there was a difference you could notice. Not a "night & day" difference as some on here report though.
-Targa Top Off impressions: Not that big of difference. This is where I wanted the biggest improvement. For me, it didn't make enough of a difference to justify the $500 cost. The steering wheel still shook, and the car was still that same noodle.
-I actually spoke with Gordon Killebrew on the phone trying to get these adjusted as good as I could. Really nice guy. He did create them, according to him, these were not used on the Challenge cars as some on here have suggested (which is strange since on V2V's website they claim a variation of the system was used on Tom Morrisons challenge car). He also stated the convertible cross brace is a waste of space and weight. He advised against using it but it was a cost effective and quick way to help with frame stiffness on the convertibles. GM liked his system but couldn't find a profitable way to implement an adjustable system on the assembly line. He actually said if I had a convertible to throw the factory cross brace away and install the bars in their place.
-Cons: Parking brake cable has to be re-routed and it seemed to rub a little on the rear bracket. This didn't effect the install, you just pull the cable out of the way and put the bracket in place. Overtime this could cause an issue, not sure. You also need a low profile jack to clear the V2V brackets when jacking the car up.
-Variations: All cars are different. I tried the torque method and the counting threads method. I could never get it 100% even. When using the torque method, I kept running out of threads on the driver side, and the bar actually started contacting the driver side floor board when tightened too much. I attribute this to bracket movement, not frame compression. The counting threads method didn't feel right either. Both sides having the same thread count resulted in the passenger side bar always feeling tighter. Also, its very awkward tightening them with a torque wrench and crows foot. It's hard to get the torque to register on the torque wrench because you aren't tightening a bolt or nut, its essentially a turn buckle system, so there is really never enough resistance (so to speak) to get the torque wrench to click (eventually got them to click at 15-20 ft.lbs.). May have been okay with an old school dial torque wrench. Each car is different, maybe my frame still had plenty of torsional rigidity? My feeling is that these bars may be more beneficial and noticeable to the earlier C4's before the frame updates. Ofcourse there are guys on here with 96's that say these are the best upgrades they did (They also spent $500 + shipping on them). This system falls into the category of, "Is it worth it?" To someone else I am sure it is.
To me, not worth the $500 cost. If someone is truly fed up with the frame flex and their car is a noodle even with the top on, these will help if you are okay with throwing down that kind of money. Infact, I think it would be a good combo in conjuntion with a Camber Brace. Idea: If these tubular bars were made into a cross brace similar to a convertible, that you could also tighten. I think it would be a winner. For me, not enough of a difference to pay full price. The car drives almost as well without the bars. No need for a weight adder at the moment. If you want to fine tune any vibrations, creeks, rattles, then these do work! The measurement test V2V has on their website is correct. The distance between the windshield header and rear b-pillar does not change when you jack the car up with these bars installed. However, that is a static enviornment with only one input on the frame (the jack itself). On a road with bumps, dips, undulations, effecting each corner of the car, things are a little different.
I never had any intentions of buying a new set for $499 + shipping. I found a guy on ebay selling a pair and won them for a good price.
-They installed easily and were extremely well made. So much so that I would go as far as saying that it was the easiest aftermarket part install I have ever done. There was no modifying or fuss involved (Aside from parking brake cable, will get to that). 30 Minutes and they were on! Ground clearance was not changed and the ZF still was the lowest point on the underbody.
-I noticed an immediate difference in how the car drove. Did it handle better? Not sure...Was the car more stable? Sure felt like it. It felt like the suspension may have been doing more of the work than the frame. There were less interior creeks, but my interior is pretty sorted out to begin with. I can't say for sure it helped with driver confidence in the corners or anything, but there was a difference you could notice. Not a "night & day" difference as some on here report though.
-Targa Top Off impressions: Not that big of difference. This is where I wanted the biggest improvement. For me, it didn't make enough of a difference to justify the $500 cost. The steering wheel still shook, and the car was still that same noodle.
-I actually spoke with Gordon Killebrew on the phone trying to get these adjusted as good as I could. Really nice guy. He did create them, according to him, these were not used on the Challenge cars as some on here have suggested (which is strange since on V2V's website they claim a variation of the system was used on Tom Morrisons challenge car). He also stated the convertible cross brace is a waste of space and weight. He advised against using it but it was a cost effective and quick way to help with frame stiffness on the convertibles. GM liked his system but couldn't find a profitable way to implement an adjustable system on the assembly line. He actually said if I had a convertible to throw the factory cross brace away and install the bars in their place.
-Cons: Parking brake cable has to be re-routed and it seemed to rub a little on the rear bracket. This didn't effect the install, you just pull the cable out of the way and put the bracket in place. Overtime this could cause an issue, not sure. You also need a low profile jack to clear the V2V brackets when jacking the car up.
-Variations: All cars are different. I tried the torque method and the counting threads method. I could never get it 100% even. When using the torque method, I kept running out of threads on the driver side, and the bar actually started contacting the driver side floor board when tightened too much. I attribute this to bracket movement, not frame compression. The counting threads method didn't feel right either. Both sides having the same thread count resulted in the passenger side bar always feeling tighter. Also, its very awkward tightening them with a torque wrench and crows foot. It's hard to get the torque to register on the torque wrench because you aren't tightening a bolt or nut, its essentially a turn buckle system, so there is really never enough resistance (so to speak) to get the torque wrench to click (eventually got them to click at 15-20 ft.lbs.). May have been okay with an old school dial torque wrench. Each car is different, maybe my frame still had plenty of torsional rigidity? My feeling is that these bars may be more beneficial and noticeable to the earlier C4's before the frame updates. Ofcourse there are guys on here with 96's that say these are the best upgrades they did (They also spent $500 + shipping on them). This system falls into the category of, "Is it worth it?" To someone else I am sure it is.
To me, not worth the $500 cost. If someone is truly fed up with the frame flex and their car is a noodle even with the top on, these will help if you are okay with throwing down that kind of money. Infact, I think it would be a good combo in conjuntion with a Camber Brace. Idea: If these tubular bars were made into a cross brace similar to a convertible, that you could also tighten. I think it would be a winner. For me, not enough of a difference to pay full price. The car drives almost as well without the bars. No need for a weight adder at the moment. If you want to fine tune any vibrations, creeks, rattles, then these do work! The measurement test V2V has on their website is correct. The distance between the windshield header and rear b-pillar does not change when you jack the car up with these bars installed. However, that is a static enviornment with only one input on the frame (the jack itself). On a road with bumps, dips, undulations, effecting each corner of the car, things are a little different.
Last edited by TorchTarga94; 06-20-2016 at 02:09 PM.
06-20-2016, 02:21 PM
#132
Race Director
06-20-2016, 02:33 PM
#133
Melting Slicks
He seemed to be sort of withdrawn from the whole stiffener bar system. Kept reiterating how well Jason makes them (which they are very nicely built). He gave me a lot of history about himself about and about how he designed them. I actually got the feeling he was a little agitated why I was asking questions about his design, but eventually the conversation got a little better once he realized I was genuinely curious. Again, may just be my car and my stupid self. Not bashing them by any means.
06-20-2016, 04:08 PM
#134
I never could get a definite answer from him! He kept restating to "make them the same" from side to side. Whether it be counting threads or the torque method. All that mattered was that it was "close" enough from side to side. I was just having issues with my click type torque wrench (Snap-On/Calibrated). I used to have an old dial beam craftsman that may have worked better. The counting thread method I kept having issues with, I would get the driver side where I wanted it, and then I would try to duplicate it on the passenger side and when I got close the bar was very hard to turn which told me the torque was much higher than the driver side.
He seemed to be sort of withdrawn from the whole stiffener bar system. Kept reiterating how well Jason makes them (which they are very nicely built). He gave me a lot of history about himself about and about how he designed them. I actually got the feeling he was a little agitated why I was asking questions about his design, but eventually the conversation got a little better once he realized I was genuinely curious. Again, may just be my car and my stupid self. Not bashing them by any means.
He seemed to be sort of withdrawn from the whole stiffener bar system. Kept reiterating how well Jason makes them (which they are very nicely built). He gave me a lot of history about himself about and about how he designed them. I actually got the feeling he was a little agitated why I was asking questions about his design, but eventually the conversation got a little better once he realized I was genuinely curious. Again, may just be my car and my stupid self. Not bashing them by any means.
06-20-2016, 04:11 PM
#135
Melting Slicks
The concept is to put the frame rails under compression by tightening the front of the car to the back of the car (essentially).
Last edited by TorchTarga94; 06-20-2016 at 04:12 PM.
06-20-2016, 04:44 PM
#136
Safety Car
Torch if I may ask how many miles on the car? what kind of shocks? original or replaced? what suspension (base or z07/z51) ? what kind of wheels/tires and sizes do you have on it?
Theres a whole of of variables that come into play but that's a great review and don't see any fault in it at all. I may be selling mine just because im going to tie in the windshield to the b pillar so I don't see the need to have these as that will stiffen up the chassis considerably and prevent flex and movement which the v2 bars help with.
I tried tightening them and when I extended the bars I noticed that the car felt better to me. Either way when it comes to steering jiggle the camber brace will definitely help there over these bars.
Theres a whole of of variables that come into play but that's a great review and don't see any fault in it at all. I may be selling mine just because im going to tie in the windshield to the b pillar so I don't see the need to have these as that will stiffen up the chassis considerably and prevent flex and movement which the v2 bars help with.
I tried tightening them and when I extended the bars I noticed that the car felt better to me. Either way when it comes to steering jiggle the camber brace will definitely help there over these bars.
06-20-2016, 07:00 PM
#137
Melting Slicks
Mike,
125,000 Miles
Replaced at 105,000 Miles with Bilstein Z51
Standard FE1 with Poly Sway Bar Bushings & Spring Cushions
17" A-molds with Continental Extreme Contact DW 285's on all four corners.
I can't wait to see the results on this. Very interested!
This is interesting. I never tried extending the bars, only tightening per the somewhat limited instructions. I wish I would have tried extending them while I still had them. I passed them along to another forum member.
Torch if I may ask how many miles on the car?
what kind of shocks? original or replaced?
what suspension (base or z07/z51)?
what kind of wheels/tires and sizes do you have on it?
Theres a whole of of variables that come into play but that's a great review and don't see any fault in it at all. I may be selling mine just because im going to tie in the windshield to the b pillar so I don't see the need to have these as that will stiffen up the chassis considerably and prevent flex and movement which the v2 bars help with.
I tried tightening them and when I extended the bars I noticed that the car felt better to me. Either way when it comes to steering jiggle the camber brace will definitely help there over these bars.
06-21-2016, 09:51 AM
#138
Instructor
Torch if I may ask how many miles on the car? what kind of shocks? original or replaced? what suspension (base or z07/z51) ? what kind of wheels/tires and sizes do you have on it?
Theres a whole of of variables that come into play but that's a great review and don't see any fault in it at all. I may be selling mine just because im going to tie in the windshield to the b pillar so I don't see the need to have these as that will stiffen up the chassis considerably and prevent flex and movement which the v2 bars help with.
I tried tightening them and when I extended the bars I noticed that the car felt better to me. Either way when it comes to steering jiggle the camber brace will definitely help there over these bars.
Theres a whole of of variables that come into play but that's a great review and don't see any fault in it at all. I may be selling mine just because im going to tie in the windshield to the b pillar so I don't see the need to have these as that will stiffen up the chassis considerably and prevent flex and movement which the v2 bars help with.
I tried tightening them and when I extended the bars I noticed that the car felt better to me. Either way when it comes to steering jiggle the camber brace will definitely help there over these bars.
07-16-2016, 08:48 AM
#139
Melting Slicks
thought I would share this in this thread, I have made a camber brace that is a different design to the produced ones, chasing the elusive "torsional rigidity" !
Next meet for me is August 7 so will report back then on how it works.
Next meet for me is August 7 so will report back then on how it works.
07-16-2016, 12:30 PM
#140
Melting Slicks
I have followed this long running thread off and on. Somewhere I remember reading the C4 was originally designed with a targa top like a C3 and at the last moment the styling group said no and the chassis group was given no time or budget to make it different. Is this fantasy or things I have imagined or is there some truth to it? Looking at the C6 central back bone seems like it really takes up no more room just trades steel for plastic. It would seem like if that was used with a trans mount inside it and a pinion mount at the back end the C beam is not needed and a weight trade of C beam gone for back bone added. It also seems like a wildly stiffer design especially if a lower plate added to cover the back bone bottom. Does everything an X brace does and a bunch more and allows the batwing to become structural as well.