Blown Motor Continued

[Speedy!]

Wanted to break this out since there's been so much discussion. I had a performance shop reach out to me over the weekend. They've had three Hellcats fail all around the 800rwhp mark on a Mustang dyno, all cylinder 7 like mine. They've had one Demon fail, 910rwhp from their Mustang dyno also cylinder 7. They've now started to recommend pistons/rods at anything over 800RWHP.

 

[Octanewide]

Oh boy lots of people out there running over 800rwhp on the stock long block.

Sent from my SM-G950U using Tapatalk

 

[Diboblo]

Not surprising.

6.1 failure was prevalent, at about 600hp, in the early days.

Forged lower end solved that.

I suspect this will be the cure, going forward.

Sent from my SM-G955U using Tapatalk

 

[oilburner]

Wanted to break this out since there's been so much discussion. I had a performance shop reach out to me over the weekend. They've had three Hellcats fail all around the 800rwhp mark on a Mustang dyno, all cylinder 7 like mine. They've had one Demon fail, 910rwhp from their Mustang dyno also cylinder 7. They've now started to recommend pistons/rods at anything over 800RWHP.

did they comment on what mods where done on the 3 hellcats an where they all the same, curious to know.

 

[jroyk]

So, are you thinking it’s more about hp than rpm, now? Did the performance shop mention the engine speeds when the others failed?

 

[Speedy!]

I still personally think it's RPM related. I'll ping them on that to see if they share that data.

 

[Beast707]

Sub'd

 

[Hellcatcfp]

Sub'd as well.

 

[Blkout]

I still personally think it's RPM related. I'll ping them on that to see if they share that data.

Would be helpful to know.

 

[Demoniccat]

Speedy, 4 cat engines, including yours, and one Demon. Same bank, same, end cylinder, I know it’s being declared rod failure, but it at least has to cross ones mind why all # 7.
Your thoughts. Coincidence, or possibly something more. Not trying to put Negative hype on it but does beg the question.

 

[G3SRT]

Speedy, did you have any cylinder misfires happening at WOT/high rpms and prior to your engine's failure?

 

[DFW_Redeye]

So is it safe to assume that the Demon/Redeye pistons are more stout and can handle 900 rwhp?

 

[Markp]

Something is definitely going on with cylinder 7s. Seems like even the majority of misfires are on cylinder 7. I would think that this is not a coincidence and is likely that all cylinder 7s are the weak link. Seems like someone made a error when designing the CAD/CAM program for machining. Could be a small mistake in the code on cylinder 7. Seems strange though that Hellcats and Demons both have a cylinder 7 issue. Can't make the same mistake twice?...can they?
https://www.hellcat.org/threads/p0307-code-at-201-miles.11957/
https://www.hellcat.org/threads/upd...der-7-misfire-codes-p0171-p0296.164889/page-2
https://www.hellcat.org/threads/cylinder-7-misfire.135121/

 

[MiHiHemi]

I'd be curious on how the temp. of that cylinder compares to the rest at high revs. Sure looks like a pattern evolving.

 

[PaVaSteeler]

following

 

[BULL]

Subscribed

 

[JustForFun]

 

[cole3986]

Pistons are weak on the Hellcat, mine did the same thing on a 8 second pass (well it ran 9.2 or 9.3 I forget) with a hole in the block.

 

[cole3986]

Speedy,

Real nice video

 

[cole3986]