Stock Rod Limit

[BGolden]

I have been a little quiet on here the last few months as we got moved into our new shop and got settled as well as Ecoboost Mustang testing.

I have been testing our EB shop car hard lately and pushing it as far as possible, and unfortunately a little too far. It lost a rod at 420 ft/lbs. I wanted to share this information with the forum so that others will not experience the same loss I did.

We will be pulling the motor over the next few days and preparing a new more robust one to power our car. It's going to be nice not to worry about that bottom end anymore.

I will try to answer any questions you guys may have.

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[SloS14]

Good to know.

 

[l2frankie]

What was done to get that power? How long was it pushing 420 before it went?

 

[arghx7]

420 lb/ft at what rpm? Do you have a torque curve you can show? 420 lb/ft that will hold to 4500 or 5500rpm is a lot harder on an engine than if you hit 420 at 3000 and the torque drops off from there. This is due to higher peak cylinder pressures.

What was the type of fuel and the spark advance? Any signs of audible spark knock or preignition? There are a lot of unanswered questions here.

 

[cosmo]

Yeah, the RPM would be great to know. 420 ft-lbs at 3500 RPM puts a lot of full bolt on and tune applications at risk. 420 ft-lbs at 5500 RPM on the other hand goes to show that the aftermarket turbo kits will need better rods.

 

[Bullitt]

This is why I'm still hesitant to do a tune. Maybe it has to do with rpms but either way, with most basic tunes making around 400 lbs/ft of torque I'm worried that all these cars with basic tunes are ticking time bombs that will go off sooner rather than later. Hearing stuff like this makes me wonder why Ford Racing is even working on a tune. Maybe they figure the car should last beyond the short warranty period and then it won't be their problem after that.

 

[LeonBorden]

Yeah but what exactly happened. Saying you lost a rod is extremely vague. Did you break a rod, break a rod bolt, spin a bearing, or what?

People shouldn't get worried about their bottom ends just yet.

 

[arghx7]

Hearing stuff like this makes me wonder why Ford Racing is even working on a tune. Maybe they figure the car should last beyond the short warranty period and then it won't be their problem after that.

Ford Racing (or whoever they are outsourcing to) has access to the designers' hardware specified hardware limitations. So they know for example what the max combustion pressure can be, and they have the equipment to see if it's actually being exceeded. They can also run durability "torture tests" in a lab.

 

[neodark]

Subscribed, I would like to hear more info as well. 420lb-ft is not far from many tunes.

 

[TheZman]

That seems like not that much power to be losing a rod that comes forged from the factory. What kind of torcher testing were you doing for that to happen? I will always be skeptical when it comes to statments like this unless i was there and saw it for myself. especially when aftermarket companies are going to be making and looking to sell there aftermarket internals and piston & rod kits. Im not saying it did happen or trying to call anybody out im just saying im skeptical.. ill wait for FORD to do there testing and come out with there tune and see what they come up with first!

 

[BGolden]

The mods are RIP Tuning intake, exhaust, and tune. (intercooler is in development) I had been pushing it hard since last Wed as we were getting ready to take it to the track. It made 420 at 3200 rpms, and 29.7 psi on MS101. The rod let go to the point where we now have a nice window to look through. This is why I do extensive testing on my own cars before pushing a customers car this hard. After what I have seen I personally would not push a car past the 370 trq mark on my dyno. I believe it is a matter of time with these rods around 400 ft/lbs. I'll know more over the next few days.

 

[Bullitt]

Yikes. Well thanks for the heads up.

 

[EcoSwag1990]

29psi is a lot though. Doesn't the livernois tune top out at 18-19psi?

 

[mtpavelka]

29psi is a lot though. Doesn't the livernois tune top out at 18-19psi?

I don't mean to speak for LMS but they said in a post they don't deviate from the stock boost levels. I'm sure LMS will speak up. Especially if I'm mistaken.

 

[l2frankie]

Nice to know this car makes hell of power with a few bolt one but that's scary knowing it can blow quick. 29 psi is alot

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