Frame question..
Thread Starter
Instructor
Joined: Aug 2014
Posts: 249
Likes: 0
I thought the same thing when I seen the picture after I put it up then I crawled under it again and it's not.. Must be a glare.. Or the hole that was drilled is oval.
Last edited by Chevrolet12; Jun 3, 2015 at 07:20 PM.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Thread Starter
Instructor
Joined: Aug 2014
Posts: 249
Likes: 0
I just need a tip on how to make a crossmember or make my c beam work which I don't think I can now that the top bolt holes are cut off. If I can get an idea for the crossmember I will get to making one.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
If you support the trans w/a x member, that will solve the trans movement issue. You'll still have the issue of the reaction tq from the diff -the C-beam being a torque arm. Will that bottom lip be enough? IDK. I'd make the x-member, install everything, then stick a GoPro under there to see how much flex and movement you have w/just the 'bottom mount design". If it flexes too much, you'll have to figure out how to tie the bottom of the C-beam to the cut back top, get a new C-beam or make one specifically to be a torque arm...specific to FIT your car, is what I mean. I SUSPECT, that over time, the bottom lip of the C beam would flex, fatigue and fail...but I don't know for sure.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
You said your engine is 550 hp. I'm going to ASSumer that it's 450 tq, trans is known, and I'm going to assume a 3.07 gear.
450x2.48x3.07=3426 ft lbs at the diff. C-beam is about 4' from the pivot point, so 4/3426=864 lbs.
Using those numbers, and not accounting for the "hit" of the converter, you're looking at a peak of ~900 lbs on that lower lip of the C-beam, lifting up on your x-memeber. Will that piece of aluminum hold that much? I think it would for a while....
450x2.48x3.07=3426 ft lbs at the diff. C-beam is about 4' from the pivot point, so 4/3426=864 lbs.
Using those numbers, and not accounting for the "hit" of the converter, you're looking at a peak of ~900 lbs on that lower lip of the C-beam, lifting up on your x-memeber. Will that piece of aluminum hold that much? I think it would for a while....
Last edited by Tom400CFI; Jun 3, 2015 at 07:41 PM.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
If it's flexing from just shifting into gear, there is no way it will hold the forces of full throttle launching.
.
Last edited by Tom400CFI; Jun 3, 2015 at 07:50 PM.
Thread Starter
Instructor
Joined: Aug 2014
Posts: 249
Likes: 0
We are saying about 550 hp at the least.. Haven't got to the dyno yet. He thinks it may be more.. You are correct on 3.07 gear. And I was meaning maybe fabricate a different way to mount the c beam to the crossmember instead of just the lower lip.. I would prefer this to be a little more stout.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Burning Brakes
Joined: Apr 2009
Posts: 1,228
Likes: 10
From: That one city...you know that one. Idaho
I think the easiest thing to try would be to remove the rubber mount from the TH400, and mount what is left of the cbeam directly to the transmission.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
I think the easiest thing to try would be to remove the rubber mount from the TH400, and mount what is left of the cbeam directly to the transmission. I didn't think it would hold and that's why I'm asking you for your advice.
I would like to have a crossmember because it just seems stronger to me.
I would like to have a crossmember because it just seems stronger to me.
Second, I don't think the x-member is stronger than a properly mounted C-beam. Remember that a x member will be very long since the frame rails at that point in the car are very wide (rocker to rocker). So unless you seriously cut into the floor/interior to get a tall x member, it's going to be tough to get a strong, stiff x member that will double as a tq arm mount. If you're going to rearrange it so that you can properly bolt the C-beam to the trans, then you don't need the x member.
IF you move forward w/the X member, then I'd fab some kind of vertical element of the member, that would interface w/the C-beam on a vertical plane, where it has it's strength. Then bolt the C-beam, rigidly to that. Does that make sense?
Thread Starter
Instructor
Joined: Aug 2014
Posts: 249
Likes: 0
I am kind of lost on what you mean by that. I think I still have the piece that was cut off the beam. I may get that welded back on and see if I can get it mounted to the transmission. Any ideas on going that route. It seems like the best route for now.
Burning Brakes
Joined: Apr 2009
Posts: 1,228
Likes: 10
From: That one city...you know that one. Idaho
For my car it would have required modifying the floor pans to make room for the crossmember.
For that I meant to use the cbeam, but remove the rubber mount is currently on the Th400.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
If it were me, I'd fab a steel unit that bolts to the same flange as the trail shaft housing, extends rearward like 1/2 a box, meets and fits inside the C'beam...then bolt the beam to that.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
The trans is strong enough on the vertical plane to handle those loads, and the C-beam is very weak torsionally, so any twisting forces (motor mounts flexing, frame flex, etc) is absorbed in the C-beem.
Team Owner
Joined: Sep 2003
Posts: 25,394
Likes: 2,741
If the original C-beam was long enough and could be used if NOT CUT I'd get another and start with a fresh C-beam that's not been whacked on. They're very inexpensive and there are many available everywhere very cheap probably very close to you. You want a D36/A4 C-beam if the older was long enough, if it was really very much to long you might want to get a D44 C-beam BUT they're not inexpensive and a little more difficult to come by. They're only slightly shorter than a D36 part but for an application that uses a D44 and an appropriate transmission it's much easier too use than to try and drill all four holes that are required and keep an appropriate alignment.