With great power comes great carnage

[tony-muscle]

Your experience is very interesting for the rest of us that are seaking more power. It will be nice to summarize in one post the sequence of weak points you have found to date so we know what to expect.

I am personally not going for that much power, but I should be up in the 400s once my dreams are all done.

1971 M-code Mach 1

 

[Jeff73Mach1]

Yes I am running a safety loop.

here are some pics as promised.

As to telling you everything that needs to be upgraded . . . I suspect I haven't found out yet.

I have installed Subframe connectors, driveshaft loop, 31 spline axles, Caltracs, 5 leaf rear springs, Moroso perches with the modifications to make them a bit stronger, Belltech lowering blocks, with 1 inch steel spacers in the back half and 4 degree shims.

and you'll be happy to know, I washed the mud off

 

[mjlan]

I would reconsider the lowering blocks if possible.

I think your power levels + sticky tires is more than the u-bolts can keep together.

Just a thought...

 

[Jeff73Mach1]

You may be right, but I'm keeping a close eye on them. After several hard launches everything seems to be holding stable. I'll continue to watch them, but would prefer to maintain my current stance if possible.

 

[Tubo]

Jeff I sure hope your getting a 4R70W ready to drop into that machine of yours.

Tubo

 

[Jeff73Mach1]

High Tubo! Good to see you around! Nope, I'm not ready to give up the clutch pedal. I can always switch to my street tires and just drift around with minimal traction. LOL

 

[Jeff73Mach1]

Well I did find another weak link tonight . . . oh the shame of being dragged home with a logging chain by a chevrolet. . . :shootself:

And it was all witnessed by forum member Joe, aka 72MustangSprint This is what happens when you shift from 1st to second at 7000 rpm and your sticky tires hook well.

Sheared the front u joint, destroyed the yoke, destroyed the driveshaft tube, Safety loop functioned as designed.

Oh well, nothing that can't be fixed.

 

[EBSTANG]

Well I did find another weak link tonight . . . oh the shame of being dragged home with a logging chain by a chevrolet. . . :shootself:

And it was all witnessed by forum member Joe, aka 72MustangSprint This is what happens when you shift from 1st to second at 7000 rpm and your sticky tires hook well.

Sheared the front u joint, destroyed the yoke, destroyed the driveshaft tube, Safety loop functioned as designed.

Oh well, nothing that can't be fixed.

There's 500 Ft lbs of torque for ya! That's sweet...just watched a show "How it's Made" on carbon fiber driveshafts and they were like 5 or 6 times stronger than steel tube! Glad the driveshaft hoop kept it contained for you Jeff!

 

[Jeff73Mach1]

Me too! I'd hate to have it shoved up through the floorboard into my keister.

 

[72MustangSprint]

Well I did find another weak link tonight . . . oh the shame of being dragged home with a logging chain by a chevrolet. . . :shootself:

And it was all witnessed by forum member Joe, aka 72MustangSprint This is what happens when you shift from 1st to second at 7000 rpm and your sticky tires hook well.

Sheared the front u joint, destroyed the yoke, destroyed the driveshaft tube, Safety loop functioned as designed.

Oh well, nothing that can't be fixed.

yes I can confirm its fast and breaks stuff. Hows the floor look?

 

[tony-muscle]

Well I did find another weak link tonight . . . oh the shame of being dragged home with a logging chain by a chevrolet. . . :shootself:

And it was all witnessed by forum member Joe, aka 72MustangSprint This is what happens when you shift from 1st to second at 7000 rpm and your sticky tires hook well.

Sheared the front u joint, destroyed the yoke, destroyed the driveshaft tube, Safety loop functioned as designed.

Oh well, nothing that can't be fixed.

That's crazy. Is there any other damage to the underside of the car?

I guess it is time to change to a stronger axle and u-joints. Hopefully that's the end of the weak links and your chain is robust to withstand monster truck. Keep us posted. Your experience is invaluable for those wanting more torque.

 

[TommyK]

I think the title to this thread should be "With great traction comes great carnage" LOL!

 

[Jeff73Mach1]

I'm looking at converting everything to 1350 series u joints and chrome moly slip joint and weld yokes. Still figuring our what is going to be best, but am strongly leaning towards having Mark Williams make me up what I need.

As to damage to the underside of the car-I haven't looked. I'm pretty sure it is nothing more than the dafety loop mounting points are going to be beat up and need to be reinforced. I'll let you know after I actually take a closer look.

 

[Jeff73Mach1]

I still haven't been able to bring myself to look under the car.

But . . . I have a plan of action now. Mark Williams would be my first choice for parts, but they are out of stock for my slip yoke and their Daytona support isn't what I want.

I've ordered a Pinion yoke, a daytona support and all the parts that I need to convert that over on the real end from Strange Engineering. Everything is going to be 1350 u joint size and all parts are premium chrome moly. At this point the only question is whether a 3" or 3 1/2 driveshaft is going to be called for. the 3" shaft is good to 7500 RPM and without an overdrive and 28.5 tall tires, I'm feeling that the margin is fine as that would take me to about 165MPH which is probably beyond what I would ever consider but if I were to go back to 26" tires that would put my driveshaft speed at it's upper limit at 150 MPH. While I shouldn't have a reason to go that fast, it wouldn't be the first time, and I've still got this crazy idea of driving in the Silver State Classic one day or with the ECTA in one of their top speed runs.

cost difference is about a hundred bucks. I think I may have talked myself into the 3 1/2 version just now.

 

[vozaday]

And I now ordered a safety loop. haha

 

[barnett468]

You could get an aluminum shaft with forged yokes and cryo treated greaseless joints . these guys also sell the mark williams slip joint

they also do real high speed balancing instead of the standard low speed balancing so there is ZERO chance of getting vibration from the shaft.

http://www.dennysdriveshaft.com/c3_aluminum_6061_t6_driveshafts.html

 

[Jeff73Mach1]

good thoughts. I would think Strange does High speed balancing, but I will verify. I am not as familiar with aluminum, but think the cost is at least 3-400.00 more. if I am wrong, then that is worth considering too.

I reached under the car and took some pictures. There is no real damage, just a bit of paint scraped off the tunnel directly above the u joint. . . . I believe the feeling I am experiencing is relief, but it might be amazement!

 

[72MustangSprint]

good thoughts. I would think Strange does High speed balancing, but I will verify. I am not as familiar with aluminum, but think the cost is at least 3-400.00 more. if I am wrong, then that is worth considering too.

I reached under the car and took some pictures. There is no real damage, just a bit of paint scraped off the tunnel directly above the u joint. . . . I believe the feeling I am experiencing is relief, but it might be amazement!

Good news, looks like you have dodged the bullet or in this case the shaft.

 

[turtle5353]

You could get an aluminum shaft with forged yokes and cryo treated greaseless joints . these guys also sell the mark williams slip joint

they also do real high speed balancing instead of the standard low speed balancing so there is ZERO chance of getting vibration from the shaft.

http://www.dennysdriveshaft.com/c3_aluminum_6061_t6_driveshafts.html

I have bought from Dennys before and it was always high quality. never got aluminum but im sure its really NICE!!

 

[Jeff73Mach1]

Well I guess I should update this as I drove the car yesterday. I cruised at 80, 90 and up a bit with zero vibration, so I think I'm in good shape. Rear end was quiet (perhaps quieter than before) but I only drove about 30 miles, so I'll reserve judgment on that until I get some more miles on the car.

I ended up getting a Mark Williams slip yoke, a strange forged pinion yoke, a strange forged aluminum daytona pinion carrier and I had a 3.5" driveshaft made locally. Everything is for 1350 u-joints. Driveshaft length is 51 1/4 and seems to be a perfect fit. U joints are the permanently greased versions.

We just pulled the pinion, not the chunk. I used a dial indicator to measure slack at the rear yoke and duplicated that on the reinstallation, adding the thinnest shim I had to the original shim. slack was exactly the same by this method, though I can't say if it changed the pattern at all. I'll likely pull the chunk and check everything in a more traditional manner once I can get over to the shop and use the lift.

I'm working on front and rear driveshaft loops, so no hard shifts or full throttle acceleration until they are done and installed. So that pretty much means I won't be driving my car. lollerz