Whipple & Broken Cranks

[rushfighterx]

Hey all, long time lurker but first time posting here. Wanted to get everyone's opinion on what generally causes the whipple to snap the crank? Is it from over tightening the belt or the design from the whipple supercharger's pulley system?
I've had 2 turbo cars in the past but recently, I purchased a whipple 10spd mustang with a 10 rib setup. I've purchased and installed the preventative measures such as the mfp crank support however I'm still a bit nervous on switching to a smaller pulley size. I have a built block from S&M Motorsports that's rated up to around 1300, the only caveat is that I still have a stock crank.
I've been contemplating just taking off the whipple kit and going back to a turbo setup after reading about all the snapped cranks in the ACMR / Gen 5 Whipple FB page. Seems like the crank will snap no matter what preventative measures you take.

Sponsored

 

[80FoxCoupe]

Subscribed

 

[Cory S]

It's a combination of side load on the snout, more weight on the snout, and moving the applied force further out on the snout, because Whipple uses the front drive (and extends it out even further --> many do this) for the blower.

 

[SheepDog]

Maybe consider installing a Crank support stud kit, if you haven't already

https://kinetikmotorsport.com/products/coyote-crank-saver-stud-kit

https://www.lethalperformance.com/apex-torque-cm-hbb-coyote-harmonic-balancer-stud-kit.html

 

[JetGray_Mach1]

I have seen tons of boosted coyotes without problems. What whp range increases the chance of this happening? and Is the upgraded rib belt part of the issue? Hope we get some solid analysis on this.

 

[80FoxCoupe]

I have seen tons of boosted coyotes without problems. What whp range increases the chance of this happening? and Is the upgraded rib belt part of the issue? Hope we get some solid analysis on this.

You won't get solid analysis on this. Additional load, rotational and side loading is a factor. How much horsepower does it take to spin a Whipple to make 1000whp? Say it takes 100hp to spin that blower. The GT crank was not intended for that application. They went with a more robust material on the predator cranks.

Crank stud and crank supports will help in mitigating some of the issues. Stay off the limiter and make sure the balancer is torqued properly.

 

[Cobra Jet]

Is the issue really the Whipple, or is it the crank sprocket failing first, which causes the catastrophic event?

See this thread for reference, as it is a known fact that even Coyotes without forced induction and those not raced have had factory crank sprocket failures,. Such a failure just leads to all out destruction if it happens at higher RPM and greater force with a supercharger:
https://www.mustang6g.com/forums/th...n-after-oil-change-today.167988/#post-3421941

Also with that known fact, no one can seem to confirm if Ford had upgraded the factory crank sprocket in the 3rd Gen to the same sprocket as offered by Ford Performance.

Discuss.

 

[JetGray_Mach1]

Bump

 

[RagmopInKona]

Just a reply from a dumb 5 decade in racer. When you balance an engine for racing/high rpm you bring the flex plate or flywheel and balancer and pulleys rods,pistons, pins, locks, rings, the works. When folks add a s/c they hang a bunch of weight off the end of the crank that was not balanced and side loading the end of the crank. They really need a roller bearing support after the pulley/belt . That cost money and takes up room .

 

[xr4x4ti]

It's a combination of side load on the snout, more weight on the snout, and moving the applied force further out on the snout, because Whipple uses the front drive (and extends it out even further --> many do this) for the blower.

This seems like a critical difference. The Roush, VMP and Predator drive the supercharger from the back via the AC belt. It looks like Whipple drive is it out in front, this would put a much higher load on the crank snout.

My .02

 

[Det_Riot]

We've ran the 10 rib kit with the MFP Support and the Kinetic Motorsports with a 3.00/20% and have not had any issues for going on 3 seasons now. I would not be concerned with the crank support added.

 

[vaeevictiss]

Is the issue really the Whipple, or is it the crank sprocket failing first, which causes the catastrophic event?

See this thread for reference, as it is a known fact that even Coyotes without forced induction and those not raced have had factory crank sprocket failures,. Such a failure just leads to all out destruction if it happens at higher RPM and greater force with a supercharger:
https://www.mustang6g.com/forums/th...n-after-oil-change-today.167988/#post-3421941

Also with that known fact, no one can seem to confirm if Ford had upgraded the factory crank sprocket in the 3rd Gen to the same sprocket as offered by Ford Performance.

Discuss.

To my knowledge its the same OPG/CS. What was changed was the dampener. APPARENTLY...the failures, someone determined, were due to harmonic vibrations at high RPMs. Ford went to a viscous fluid dampener on the gen 3 coyotes and this problem is supposedly "fixed". I couldn't find anything online about an 18+ failure so I started asking around. Only person to say he's seen them was Wengerd and he said they were pushing the 800-900hp range and they didn't explode, just cracked, so I'm assuming it didn't cause a catastrophic engine failure. So it seems pretty rare now.

 

[80FoxCoupe]

To my knowledge its the same OPG/CS. What was changed was the dampener. APPARENTLY...the failures, someone determined, were due to harmonic vibrations at high RPMs. Ford went to a viscous fluid dampener on the gen 3 coyotes and this problem is supposedly "fixed". I couldn't find anything online about an 18+ failure so I started asking around. Only person to say he's seen them was Wengerd and he said they were pushing the 800-900hp range and they didn't explode, just cracked, so I'm assuming it didn't cause a catastrophic engine failure. So it seems pretty rare now.

The reason for the viscous damper on 18up is because it's a different engine. DI, larger bore, heavier piston, more rpm etc. Different harmonic profile would require a different balancer.

Failure rate depends on who you ask. Whatever your position on these failures is, address them with precautions suitable to you or do nothing at all. Cause at the end of the day, this is either an issue or it isnt.

 

[bankyf]

The reason for the viscous damper on 18up is because it's a different engine. DI, larger bore, heavier piston, more rpm etc. Different harmonic profile would require a different balancer.

Failure rate depends on who you ask. Whatever your position on these failures is, address them with precautions suitable to you or do nothing at all. Cause at the end of the day, this is either an issue or it isnt.

I'm fairly certain that some time around 2020 they switched back to the non-viscous damper, so I'm not sure it was for the reasons you mentioned.

 

[bankyf]

Is the issue really the Whipple, or is it the crank sprocket failing first, which causes the catastrophic event?

See this thread for reference, as it is a known fact that even Coyotes without forced induction and those not raced have had factory crank sprocket failures,. Such a failure just leads to all out destruction if it happens at higher RPM and greater force with a supercharger:
https://www.mustang6g.com/forums/th...n-after-oil-change-today.167988/#post-3421941

Also with that known fact, no one can seem to confirm if Ford had upgraded the factory crank sprocket in the 3rd Gen to the same sprocket as offered by Ford Performance.

Discuss.

I believe that to be true. I'm fairly certain they went to a forged sprocket for 3rd Gen. The sprocket on my car looked identical to the Ford Performance sprocket I purchased. Ended up getting a Boundary after I saw that. The Ford performance catalog eludes to it as well in my opinion.

Sponsored