BTR Cam 223/228, .604"/.604", 114 LSA

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He floored it when he was just over 30 mph. Its not just traction control that's the problem, you can hear the wheels spinning every time traction control gives some freedom.

 

Anyone have proof about the driveshaft? I've read that it supposedly only happens on 2wd trucks. 4x4 cc/sb its supposed to be ok because the driveshaft is that much shorter? 

Theoretical critical speed of the stock aluminum driveshaft tube with a length of 70.5” which is the length of a crew cab short box 4x4, calculated at it’s most narrow point of 4” is 5,200 rpm.

 

This is assuming the physical properties of the driveshaft material are comparable to a homogenous 6061 aluminum tube of the same thickness (0.083”). The OEM driveshaft contains a thin, cardboard-like material in between two separate layers of aluminum which, when combined, make the final tubing material. Unfortunately, I have not found any objective data regarding the strength properties of this material combination compared to homogenous 6061, however, anecdotal reports of the driveshaft failures in our trucks seem to occur at similar speeds.

 

With 3.42 gears and 31.9” diameter tires, with a 6L80 trans, 5,200 rpm would be 144mph (engine RPM of 3,483)

 

With 3.73 gears and everything else the same, it drops to 132mph.

 

If you extend the length of the shaft by only 5% you will see the critical speed decrease by 10%.

 

It is commonly accepted that at your maximum cruising speed (70mph for example), your driveshaft should spin less than 50% of its critical speed. At or above 50% critical speed will result in vibration. This is interesting because it is consistent with the many reports of people experiencing vibration above 75mph in our trucks (50% driveshaft critical speed occurs at 72mph with 3.42 gears).

 

None of this takes into account the numerous other variables that will impact driveshaft strength and stress such as the yokes, how well it’s balanced, continually variable pinion angle while driving, driveline shock from hard shifting gears or sudden loss and reacquisition of traction.

 

I didn’t intend to write a book above, sorry for the long read, but I did a fair amount of research when I decided to upgrade my 5.3 CCSB 4x4 driveshaft from the stock unit to a 5” x 0.125” x 71.5” aluminum driveshaft. The critical speed now is above 6,300rpm and the torsional yield went from 4570 lb-ft to over 10,000 lb-ft.

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Thanks I was aware of how to turn traction control and StabiliTrack off. Video was me just playing around. I understand the concern on the driveshaft too. Thing to note is a crew cab 2WD truck has a considerably longer driveshaft than the crew cab 4WD truck like mine. I am planning on a two piece conversion in the near future. Thanks

I figured as much but thought I’d throw it out there just in case. The 2 piece driveshaft is a solid choice. Great video btw. I agree, your midrange is awesome.

[M1ck3y]

I haven't heard of anyone with blowers grenading the driveshaft with the stock speed limiter in place? Would it not be the same for a cam? I'd like to know what the limit is for the 8spd/3.23. The 14 6spd/6.2 3.42 had a factory limit of 110. Was there a driveshaft change for 15 model year or was it simply the gearing in the 8spd that brought on the change to 98.  

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I haven't heard of anyone with blowers grenading the driveshaft with the stock speed limiter in place? Would it not be the same for a cam? I'd like to know what the limit is for the 8spd/3.23. The 14 6spd/6.2 3.42 had a factory limit of 110. Was there a driveshaft change for 15 model year or was it simply the gearing in the 8spd that brought on the change to 98.  

I’m not sure what the limiter is set at for the various vehicles, model years, etc...Without re-gearing to much shorter gears, or a drastic reduction in tire diameter, it’s unlikely you would have a failure from reaching the driveshaft’s critical speed with the factory speed limiter still active.

Your 8th gear ratio is 0.65 which is very close to the 0.67 of sixth gear in the 6L80. I think it is entirely plausible they set the original limit too close to the critical speed of the shaft and they brought it down in later model years to increase the safety margin. Your taller rear end gears further support this theory since the driveshaft is spinning even slower compared to a 6L80 with 3.42s.

From what I’ve read, there are a few different driveshafts on these trucks. Some are steel, some are aluminum. miller74’s CCSB 4x4, for example, had a steel shaft before he swapped to the same 5” aluminum shaft that I have.

I too am yet to read about a failure of the driveshaft in a boosted truck from excessive torque. I still think there is merit in bolstering areas of known, or calculated, weakness. I blew up a brand new C6 Vette’s rear end with one run down the drag strip. Not because the LS3’s 400lb-ft of torque exceeded the capability of the driveline, far from it. It was because too aggressive of a launch, with traction control turned off, caused wheel hop and repeated shock to the driveline. That repair was over $6500

The OP replaced his cam to improve the reliability of his truck by eliminating the AFM lifters which are a known “weak point”. Sure, they may not fail for most of the trucks out there, but they did on the OP’s. And when it was “repaired” the first time, they refused to investigate or replace what he rightfully believed to be a damaged cam. Nice, a ticking time bomb gradually destroying his engine because of a shoddy repair of a known weak point in the system. No thank you.

Same goes for the driveshaft.

[6.2_GMC_DEN]

Update: First tuner couldn't refine all my quirky issues. I then purchased a HP Tuner MPVI and starting working with a remote tuner, that didn't go well. So at my 3rd tuner now and truck is being tuned by #3. I have spent way too much on tuning and not real happy with some folks. These newer trucks are a completely different animal and a bunch different than the LS stuff. I will update once I get it back hopefully this week from #3.

 

Here is link to my current tuners site. He has one of the baddest dyno's in the country!

 

https://dbrhighperformance.com/services/dyno-tuning/

[300 Blackout]

Update: First tuner couldn't refine all my quirky issues. I then purchased a HP Tuner MPVI and starting working with a remote tuner, that didn't go well. So at my 3rd tuner now and truck is being tuned by #3. I have spent way too much on tuning and not real happy with some folks. These newer trucks are a completely different animal and a bunch different than the LS stuff. I will update once I get it back hopefully this week from #3.
 
Here is link to my current tuners site. He has one of the baddest dyno's in the country!
 
https://dbrhighperformance.com/services/dyno-tuning/

Sucks to hear that about the previous two tune attempts. I’ve contemplated getting a HPT MPVI and beginning one of their intro to tuning courses to learn it myself specifically because of the issues you’ve run into. It would be a huge undertaking and lots to learn...

What are the quirks that you’re having a hard time ironing out?

[kennerz]

On ‎12‎/‎29‎/‎2018 at 8:34 PM, M1ck3y said:

I haven't heard of anyone with blowers grenading the driveshaft with the stock speed limiter in place? Would it not be the same for a cam? I'd like to know what the limit is for the 8spd/3.23. The 14 6spd/6.2 3.42 had a factory limit of 110. Was there a driveshaft change for 15 model year or was it simply the gearing in the 8spd that brought on the change to 98.  

the factory limit on my 6.2 was 99mph and it would hit it effortlessly, then all done. Tuned now so will go as far as you want but that isn't smart knowing the limits of the DS and tires. - sorry for the derail.

[6.2_GMC_DEN]

14 hours ago, 300 Blackout said:

Sucks to hear that about the previous two tune attempts. I’ve contemplated getting a HPT MPVI and beginning one of their intro to tuning courses to learn it myself specifically because of the issues you’ve run into. It would be a huge undertaking and lots to learn...

What are the quirks that you’re having a hard time ironing out?

Man there were a bunch of issues. Transmission shifting all wrong from harsh engagement, long shift times, shifting st wrong RPM/MPH, the list goes on and on... With engine the idle was set to high, it would die at stop signs, it ran rough at a idle and would vibrate the whole truck, it would surge at cruising speeds, herky jerky taking off, and much more. All frustrating and expensive.

[M1ck3y]

19 hours ago, kennerz said:

the factory limit on my 6.2 was 99mph and it would hit it effortlessly, then all done. Tuned now so will go as far as you want but that isn't smart knowing the limits of the DS and tires. - sorry for the derail.

?

 

I mean the limit of the driveshaft...

Edited February 23, 2019 by M1ck3y

[kennerz]

5 hours ago, M1ck3y said:

mph?

 

I mean the limit of the driveshaft...

Answer was there boss. The terminal shaft speed is not much higher than the governed limit. People have reported catastrophic shaft failures on the dyno at not much over 100mph speedo reading. Let's say any shaft speed (not sure of actual shaft rpm) over 110MPH you are playing roulette. You "may" be ok, maybe not. 

 

The construction is tin can thin. no exaggeration.

 

to the OP, sorry for your tuning blues, hope you find the "right" guy. Shows you how many clowns are out there. Still 435 rwhp with a poor tune is nothing to sneeze at. once you get it dialed it should be a beast. I would hit up the camaro6 forums and see if there is a tuner with a solid reputation with the LT1/L86 platform. There are people out there who know how to do this, just you need someone with some validation that they are proficient with this engine. Weapon X in Ohio, Houston has some top guys, Jeremy Formato of Fasterproms. Cunningham motorsports in CA. There are guys out there who shouldn't struggle with your combo at all.

 

Good Luck

[6.2_GMC_DEN]

This was final results. 28 degrees of timing and wouldn't make more at 30.

 

On E85. It's all she's got.

[M1ck3y]

10 hours ago, kennerz said:

Answer was there boss. The terminal shaft speed is not much higher than the governed limit. People have reported catastrophic shaft failures on the dyno at not much over 100mph speedo reading. Let's say any shaft speed (not sure of actual shaft rpm) over 110MPH you are playing roulette. You "may" be ok, maybe not. 

 

The construction is tin can thin. no exaggeration.

 

to the OP, sorry for your tuning blues, hope you find the "right" guy. Shows you how many clowns are out there. Still 435 rwhp with a poor tune is nothing to sneeze at. once you get it dialed it should be a beast. I would hit up the camaro6 forums and see if there is a tuner with a solid reputation with the LT1/L86 platform. There are people out there who know how to do this, just you need someone with some validation that they are proficient with this engine. Weapon X in Ohio, Houston has some top guys, Jeremy Formato of Fasterproms. Cunningham motorsports in CA. There are guys out there who shouldn't struggle with your combo at all.

 

Good Luck

Ok, Thanks for clarifying. I had just assumed gm would have left more room between the limiter and the limits of the driveshaft. Not too smart having a driveshaft that blows up 1mph over the limiter.

[JONBLARC7]

Wish you didn't take the headers off.  I bet it would have been close to 450 with headers.

 

 

[country_09]

With headers on heavy 33s mine dyno’d at 415/430 to the wheels with this same cam. Never did an e85 tune on it though. Was planning on swapping the cam out for a different one and adding a whipple to it within the next year. Good numbers! 

[6.2_GMC_DEN]

10 hours ago, country_09 said:

With headers on heavy 33s mine dyno’d at 415/430 to the wheels with this same cam. Never did an e85 tune on it though. Was planning on swapping the cam out for a different one and adding a whipple to it within the next year. Good numbers! 

Any tuning issues with yours? Especially when coming to a stop? (Driveline clang).