LS1 T56 vs. LT1 T56 similarities/differences

[chevynut]

It really does not matter what Cnut uses on his car because it is a show car.

Thanks for the compliment. It's a show car that will actually perform when I choose to drive it, not a cobbled up beater drag car.

[chevynut]

On the OT ladder bars, not only does NHRA require 3/4" ends with a safety loop, they must be solid eye style, not a spherical bearing.

Thanks for that info. Since I won't be drag racing the car, I'm not sure how NHRA rules really fit my application but it does give some perspective. However, the application is somewhat different as mine will be a street car. The C4 differential is supported at three points, two behind the differential and one in front of it. Differential rotation around the halfshafts is constrained by all three points. There's urethane bushings at each point and 1/2" bolts supporting them (12mm at the batwing). The torque arm is 50" long from the center of the halfshafts and the batwing connections are about 5" from the center of the halfshafts. All connections are non-movable, meaning they don't need to articulate.

I did a bending stress calculation assuming ALL the load is carried by the torque arm, and I have a factor of safety of at least 5. I used a coefficient of friction of 0.75 for the tires. I found a source saying 0.7 is typical for normal street tires on dry pavement, 0.9 for really sticky tires on dry pavement, and 1.0-1.5 for drag slicks which I'll never use. Even at a COF of 1.0 I have a safety factor over 4. Fatigue isn't an issue until you hit about half the UTS (endurance limit), which is at least 2X the stress I calculated, and that's after millions of cycles.

Of couse some people don't believe in engineering calculations...because they don't understand engineering. LMAO!

[Rick_L]

Interesting, I haven't seen the 2016 book.

The solid eye rod ends, along with the 3/4" rod end size and the straps (as opposed to spherical rod end bearings) have been required by NHRA for ladder bars for 30 years or more. This is for ladder bars, 4 links still use the spherical rod end bearings. Difference is, on a 4 link there's no bending, it's either tension or compression.

[chevynut]

The solid eye rod ends, along with the 3/4" rod end size and the straps (as opposed to spherical rod end bearings) have been required by NHRA for ladder bars for 30 years or more.

So it's interesting that virtually all of them I see have spherical rod ends on the front, and often solid on the rear.

http://www.jegs.com/i/JEGS+Performan...FQiqaQodDlUCOA

JEGS Ladder Bars & Components
JEGS Ladder Bars are a perfect rear suspension for Street Rod and/or Drag Race applications. They are less complicated than a four link and easier to set up. The Adjustable Ladder Bar kit allows for quick adjustment of pinion angle and pre-load. Includes safety loops that are required by the NHRA. Made in the USA.

http://chassisengineering.com/index....product_id=393

[55 Rescue Dog]

Thanks for that info. Since I won't be drag racing the car, I'm not sure how NHRA rules really fit my application but it does give some perspective. However, the application is somewhat different as mine will be a street car. The C4 differential is supported at three points, two behind the differential and one in front of it. Differential rotation around the halfshafts is constrained by all three points. There's urethane bushings at each point and 1/2" bolts supporting them (12mm at the batwing). The torque arm is 50" long from the center of the halfshafts and the batwing connections are about 5" from the center of the halfshafts. All connections are non-movable, meaning they don't need to articulate.

I did a bending stress calculation assuming ALL the load is carried by the torque arm, and I have a factor of safety of at least 5. I used a coefficient of friction of 0.75 for the tires. I found a source saying 0.7 is typical for normal street tires on dry pavement, 0.9 for really sticky tires on dry pavement, and 1.0-1.5 for drag slicks which I'll never use. Even at a COF of 1.0 I have a safety factor over 4. Fatigue isn't an issue until you hit about half the UTS (endurance limit), which is at least 2X the stress I calculated, and that's after millions of cycles.

Of couse some people don't believe in engineering calculations...because they don't understand engineering. LMAO!

You don't need to be an engineer, just common sense is all it takes to design a better/safer mount. Calculations are not always a home-run, and plenty of stuff seems to break for the same reason.

[WagonCrazy]

...so much for expecting anyone to stay on topic here...

Rick asked about T56 dimensions. I complied with confriming Laszlo's dimensions posted by measuring my actual setup.

Would you guys PLEASE start new topics if you want to piss all over each other about anything other than the topic in the original post.

PLEASE? it's a waste of my time to rifle thru all of this all the time....

[Rick_L]

I feel really bad about this rod end deal, because I don't think that Jegs or Summit's suppliers are going to sell anything that doesn't meet the rules.

But, I swear I didn't make this up, at least I don't think so. Summit does sell solid rod ends, example the Competition Engineering C6150. (Note: I tried to get an image pasted, but it didn't work out.) Also if you look at the Competition Engineering ladder bar kits, they do use solid rod ends on the axle end of their ladder bars. Perhaps that's where NHRA mandated them, but I kind of doubt it.

The other half of this deal is that the threads are going to be the weakest part of the rod end on the front of a ladder bar - at least if you use a decent rod end.

Sorry for all the confused I caused.

Now back to more OT bullshit, such as discussion why ladder bar mounts are never single shear.

[55 Rescue Dog]

...so much for expecting anyone to stay on topic here...

Rick asked about T56 dimensions. I complied with confriming Laszlo's dimensions posted by measuring my actual setup.

Would you guys PLEASE start new topics if you want to piss all over each other about anything other than the topic in the original post.

PLEASE? it's a waste of my time to rifle thru all of this all the time....

I just don't know any better I guess. Even though there is a lot of forum etiquette out there, I still think of a thread, as one thing leading to another, like branches on a tree. It should be mostly about sharing ideas, to make one take a second look. One thing always leads to another. Every time you change one thing, it seems to cause another issue, that someone might not think about. Thinking out of the box, is all it should be about.

[Rick_L]

I agree, but there's a clear limit. And it's been passed multiple times here. In all cases because some smart ass was stirring the pot.

Since I got the answer I needed after a bit of discussion and Paul's measurements (thank you again), I'm not pissed, since this isn't part of my trophy book.

[55 Rescue Dog]

So it's interesting that virtually all of them I see have spherical rod ends on the front, and often solid on the rear.

http://www.jegs.com/i/JEGS+Performan...FQiqaQodDlUCOA

JEGS Ladder Bars & Components
JEGS Ladder Bars are a perfect rear suspension for Street Rod and/or Drag Race applications. They are less complicated than a four link and easier to set up. The Adjustable Ladder Bar kit allows for quick adjustment of pinion angle and pre-load. Includes safety loops that are required by the NHRA. Made in the USA.

http://chassisengineering.com/index....product_id=393

Here we go again. IMO, a ladder bar set-up should be illegal on the street, and was never used on a production car, which isin many ways, more dangerous than no parking brake, at any speed.