57 Chassis C4 Corvette Front and Rear, Stage 4 + SS Kit + 32 Gallon Fuel Tank by Hot

[rat_rod_russell]

Originally Posted by brakebuster

j.w. but why is the rear swaybar attached to the lower link. ive never seen it done that way before

Its because of the fuel tank location on the 55-57 Chevy's and the modification required to those cars to make the sway bar fit the body if it was still on top like in the C4 corvettes. This takes care of a lot of problems with the longer wheel base too and you have a bunch of other stuff that has been moved and you just don't see like it sits here. Migrated instant centers of the rear swing arm, extended anti squat instant center and so fourth. By giving the rear sway bare less mechanical advantage over the rear we get a softer sway bar without having to buy a new one and we can use the OE Corvette bar that comes with the suspension. (so its free )

Thanks
-Russell

[jy211]

2 door

[214Chevy]

Very nice!! I love the frame set up.

[ccracin]

Originally Posted by rat_rod_russell

Its because of the fuel tank location on the 55-57 Chevy's and the modification required to those cars to make the sway bar fit the body if it was still on top like in the C4 corvettes. This takes care of a lot of problems with the longer wheel base too and you have a bunch of other stuff that has been moved and you just don't see like it sits here. Migrated instant centers of the rear swing arm, extended anti squat instant center and so fourth. By giving the rear sway bare less mechanical advantage over the rear we get a softer sway bar without having to buy a new one and we can use the OE Corvette bar that comes with the suspension. (so its free )

Thanks
-Russell

Very nice work. The chassis looks good. I just have to comment on the rear sway bar location as well. You may want to have someone do an FEA analysis on that idea. Between the HAZ created by welding the bracket to the tube and the loading in compression as well as bending it worries me. Long slender tubes in compression have to resist buckling. Obviously these types of 4 bar set-ups are well proven, but when you apply a load like that between the fixing points of the bar you are increasing the probability of buckling under load. I can't say for sure this is going to be the case, but without some calculations and investigation, I personally would go with a different solution. I'm not throwing stones, just my personal opinion. I wouldn't want to see any accidents happen.

[brakebuster]

Originally Posted by rat_rod_russell

Its because of the fuel tank location on the 55-57 Chevy's and the modification required to those cars to make the sway bar fit the body if it was still on top like in the C4 corvettes. This takes care of a lot of problems with the longer wheel base too and you have a bunch of other stuff that has been moved and you just don't see like it sits here. Migrated instant centers of the rear swing arm, extended anti squat instant center and so fourth. By giving the rear sway bare less mechanical advantage over the rear we get a softer sway bar without having to buy a new one and we can use the OE Corvette bar that comes with the suspension. (so its free )

Thanks
-Russell

thank you for the explanation

[rat_rod_russell]

Originally Posted by brakebuster

thank you for the explanation

Originally Posted by 509Chevelle

Very nice!! I love the frame set up.

Thank you, thank you.

Originally Posted by jy211

2 door

I'll think about it. But the idea of a corvette suspension 4 door with 600 HP Twin turbos just sounds so wrong its funny. I can here it now "You got wiped, by a 4 door"

I'm thinking that everyone will be able to just climb in and take off or just open the back door and drop the parts on the floor, little stuff like that. IF this were my only hot rod I'd think about it but I'm planning a wicked 55 Sedan sometime in the future.

Originally Posted by ccracin

Very nice work. The chassis looks good. I just have to comment on the rear sway bar location as well. You may want to have someone do an FEA analysis on that idea. Between the HAZ created by welding the bracket to the tube and the loading in compression as well as bending it worries me. Long slender tubes in compression have to resist buckling. Obviously these types of 4 bar set-ups are well proven, but when you apply a load like that between the fixing points of the bar you are increasing the probability of buckling under load. I can't say for sure this is going to be the case, but without some calculations and investigation, I personally would go with a different solution. I'm not throwing stones, just my personal opinion. I wouldn't want to see any accidents happen.

Thanks I apprentice you taking time to voice a valid opinion. But let me know if this makes since. The lower link of the 4 bar when under acceleration is not pushed forward in a buckling load but rather pulled in stretching as the knuckle is twisted forward so the arm will not see both extreme loads at the same time. Also the lower arm is so short that there is not that much leverage on the arm. Tubes are .125" wall DOM 1020 (mild steel) and all tig welded. Finally for practical purpose we tested this mounting method on my black and white 57 Chevy that I road raced and auto crossed for 3k miles and streeted for another 9k and never had any issues with the rear sway bar either. (P.S. The black and white car has thinner wall, smaller diameter tubing too.)

Later
-Russell

[fleet]

Looks good Russell.

Here's an idea if you decide to do the 4 door...

Give it the much better '57 Chevy coupe 'look' by copying the design of say the Mazda RX-8... how they keep the coupe look with the larger sized front doors with door handles; and the semi stealth smaller rear doors without door handles.

For me the door handles on only the front doors draw your eye to those doors.

[rat_rod_russell]

Originally Posted by compos mentis

Looks good Russell.

Here's an idea if you decide to do the 4 door...

Give it the much better '57 Chevy coupe 'look' by copying the design of say the Mazda RX-8... how they keep the coupe look with the larger sized front doors with door handles; and the semi stealth smaller rear doors without door handles.

For me the door handles on only the front doors draw your eye to those doors.

Interesting Idea, but the car I'm getting is already done. We're not the most awesome sheetmetal and I wouldn't want to bit that off as a short term project. Plus the 4 door I'm looking at is already done. I'll just drop it on my chassis then rock and roll.

Originally Posted by deuce_454

the rest of the frame looks great though.. but that mount needs fixing

looks like it works to me

https://www.youtube.com/user/RatRodRu.../1/qXEUpuXsHEk

Because the diff is mounted rigid to the front diff there is no twisting to the bolts just stretching. So the stress goes straight into the metal. You might notice that mount is .250" where the rest of the frame it .125" And for super HP applications we go the bottom of the diff and take it forward to the rear cross member just in front of it to spread the load out across the frame.

On my C5/C6 conversion 57 Chevy truck I learned that lesson a few times where I removed the transaxle but kept the corvette rear end. I build a diff adapter to put a traditional drive shaft yoke to the C5 C6 corvette rear. That diff we rubber mounted on 3 sides and it snapped the bolts in half at only 500 miles. Hit the link in my sig and you'll see what I'm talking about.

The torque arm on the C4 corvettes is as much of an "ease of assembly" or top down assembly design idea as it was for leverage. Do notice that the 5th gen camaros and 2009 Vipers went away front the torque arm in favor of short mounted differentials.

The chassis in the photos is #46 and never have we had some one break and differential except me. I was testing the small Dana 36 at the drag strip to see how much abuse they would take.

Thanks
-Russell

[deuce_454]

I see a big flaw. the pinion support si hardmounted to the frame, and the rest of the centersection is rubbermounted...

and eliminating the longitudinal arm in favour of a rigid mount shows that whoever did the design hasnt done the math.



allow me to demonstrate:
500 ft/lbs of engine tourque, 3:1 first gear ratio, 3.55 rear end gearing = 500x3x3.55= 5325 ft pound of tourque to the halfshafts, and 5325 footpounds of opposite tourque acting on the diff... if teh distance from the halfshafts to the mounting pad is one foot.. then you will have over 5000 pounds of pressure on the pad... AND the same on the rubber in the transverse mount.. the rubber will deform.. and the steel in the mount on the diff will deform .. but the rubber will rebound...

if you guys had retained the longitudinal tourquer arm (that GM engineered for a reason i moght add)

the length of the arm (5-6 feet) would have reduced the pressure on the forward mount to about 1000 pounds... AND the rubber in the tranny to torquearm mount would not permanently deform and also reduce noise over your solid solution...

the rest of the frame looks great though.. but that mount needs fixing

[ccracin]

Originally Posted by rat_rod_russell

Thanks I apprentice you taking time to voice a valid opinion. But let me know if this makes since. The lower link of the 4 bar when under acceleration is not pushed forward in a buckling load but rather pulled in stretching as the knuckle is twisted forward so the arm will not see both extreme loads at the same time. Also the lower arm is so short that there is not that much leverage on the arm. Tubes are .125" wall DOM 1020 (mild steel) and all tig welded. Finally for practical purpose we tested this mounting method on my black and white 57 Chevy that I road raced and auto crossed for 3k miles and streeted for another 9k and never had any issues with the rear sway bar either. (P.S. The black and white car has thinner wall, smaller diameter tubing too.)

Later
-Russell

Technically, that is not correct. With an independent set up like you have all torque loads essentially will be reacted by the center section. The knuckles in this case are just carriers and do not react any torque. If they do, you have a bad bearing. Therefore when under acceleration the wheels are pushing forward on the chassis. Consequently all 4 bars of the 4 bar are in compression with this design. This is unlike a solid rear axle with fixed bird cages and a 4 bar. As I said before, I can't say that you will definitely have a problem without much more info. If you have run this before and have success then you should be good. It never hurts to discuss these types of things. The chassis looks nice, I'm sure your customer will be pleased. Keep up the good work.