How much hp can the stock rods take?
08-29-2014, 12:54 PM
#1
How much hp can the stock rods take?
I'm pulling the engine on my car, and I was looking around at various upgrades like forged pistons, rods, etc.
I found some pictures of the stock rods [of course I should be able to see them in person as soon as I get the engine out], and from what I can see they look pretty stout.
I've been building Ford engines for over 30 years now, and just got rid of a 65 Mustang fastback with a 351w stroker that used the stock 351w cast iron rods.
The engine dyno'd 570fwhp with those stock bolts, and I beat the Hell out of that engine, never had a problem. I've also built many stock rod 302/5.0l engines with well over 300fwhp, and never had a problem revving to 6500rpms even with the stock 5/16 bolts [of course I changed the bolts to ARP, but they were still the same "small" 5/16's.].
So with all of the parts for the 3.5l engine being a bit higher vs the domestic parts I was wondering at around what point the stock rods give up. ..................thanks.
I found some pictures of the stock rods [of course I should be able to see them in person as soon as I get the engine out], and from what I can see they look pretty stout.
I've been building Ford engines for over 30 years now, and just got rid of a 65 Mustang fastback with a 351w stroker that used the stock 351w cast iron rods.
The engine dyno'd 570fwhp with those stock bolts, and I beat the Hell out of that engine, never had a problem. I've also built many stock rod 302/5.0l engines with well over 300fwhp, and never had a problem revving to 6500rpms even with the stock 5/16 bolts [of course I changed the bolts to ARP, but they were still the same "small" 5/16's.].
So with all of the parts for the 3.5l engine being a bit higher vs the domestic parts I was wondering at around what point the stock rods give up. ..................thanks.
08-29-2014, 01:21 PM
#2
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if it's a DE
I'm pulling the engine on my car, and I was looking around at various upgrades like forged pistons, rods, etc.
I found some pictures of the stock rods [of course I should be able to see them in person as soon as I get the engine out], and from what I can see they look pretty stout.
I've been building Ford engines for over 30 years now, and just got rid of a 65 Mustang fastback with a 351w stroker that used the stock 351w cast iron rods.
The engine dyno'd 570fwhp with those stock bolts, and I beat the Hell out of that engine, never had a problem. I've also built many stock rod 302/5.0l engines with well over 300fwhp, and never had a problem revving to 6500rpms even with the stock 5/16 bolts [of course I changed the bolts to ARP, but they were still the same "small" 5/16's.].
So with all of the parts for the 3.5l engine being a bit higher vs the domestic parts I was wondering at around what point the stock rods give up. ..................thanks.
I found some pictures of the stock rods [of course I should be able to see them in person as soon as I get the engine out], and from what I can see they look pretty stout.
I've been building Ford engines for over 30 years now, and just got rid of a 65 Mustang fastback with a 351w stroker that used the stock 351w cast iron rods.
The engine dyno'd 570fwhp with those stock bolts, and I beat the Hell out of that engine, never had a problem. I've also built many stock rod 302/5.0l engines with well over 300fwhp, and never had a problem revving to 6500rpms even with the stock 5/16 bolts [of course I changed the bolts to ARP, but they were still the same "small" 5/16's.].
So with all of the parts for the 3.5l engine being a bit higher vs the domestic parts I was wondering at around what point the stock rods give up. ..................thanks.
08-29-2014, 02:59 PM
#3
Registered User
M-train, it depends on how you plan to build power inside the engine. A big ol’ turbo that takes a bit to build pressure, but then comes on like gangbusters, will create a huge brake mean effective pressure in the cylinder all at once. The Z crank is a stout heavy unit as is the flywheel, drive train, etc. This burst of torque can instantaneously push down on the piston, but all that mass from the crank on down takes a bit of time to catch up. The poor connecting rod is in the middle of this battle and takes a beating and may bend.
A supercharger on the other hand, builds pressure in a much more linear fashion. The parts downstream from the rods will find it much easier to keep up with the increasing pressure on the piston.
The brilliant Lexus LFA V10 engine gets by with svelte little lightweight rods, notwithstanding the fact that the LFA is one of the quickest revving high horsepower engines ever. The reason all the weightless components inside the engine hold together is in the shape of the torque curve.
A supercharger on the other hand, builds pressure in a much more linear fashion. The parts downstream from the rods will find it much easier to keep up with the increasing pressure on the piston.
The brilliant Lexus LFA V10 engine gets by with svelte little lightweight rods, notwithstanding the fact that the LFA is one of the quickest revving high horsepower engines ever. The reason all the weightless components inside the engine hold together is in the shape of the torque curve.
08-30-2014, 09:21 AM
#4
M-train, it depends on how you plan to build power inside the engine. A big ol’ turbo that takes a bit to build pressure, but then comes on like gangbusters, will create a huge brake mean effective pressure in the cylinder all at once. The Z crank is a stout heavy unit as is the flywheel, drive train, etc. This burst of torque can instantaneously push down on the piston, but all that mass from the crank on down takes a bit of time to catch up. The poor connecting rod is in the middle of this battle and takes a beating and may bend.
A supercharger on the other hand, builds pressure in a much more linear fashion. The parts downstream from the rods will find it much easier to keep up with the increasing pressure on the piston.
The brilliant Lexus LFA V10 engine gets by with svelte little lightweight rods, notwithstanding the fact that the LFA is one of the quickest revving high horsepower engines ever. The reason all the weightless components inside the engine hold together is in the shape of the torque curve.
A supercharger on the other hand, builds pressure in a much more linear fashion. The parts downstream from the rods will find it much easier to keep up with the increasing pressure on the piston.
The brilliant Lexus LFA V10 engine gets by with svelte little lightweight rods, notwithstanding the fact that the LFA is one of the quickest revving high horsepower engines ever. The reason all the weightless components inside the engine hold together is in the shape of the torque curve.
So the question remains, how far has anyone here taken the stock rods? Anyone got a 400hp turbo setup with them, or a 300hp na high rpm engine with the stock rods?
Thanks.
08-30-2014, 11:20 AM
#7
I don't think it's the horsepower you should be asking, but the amount of torque it can handle... The vq motors weren't built for f/I , but sure is impressive on what it can handle. Rods are the weakest point in the motor I'm sure we all know that.
Superchargers don't push out as much torque as turbos do.
Superchargers don't push out as much torque as turbos do.
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09-01-2014, 11:34 AM
#12
Did you read the whole thread?
I was using the Ford 5.0l/302 rod as a reference to known strength vs the Nissan rod for which I don't know the limits. The rods are close to each other in size, and make, AND I have one of each rod to compare.
If your building a mild performance engine on a budget, it might be a good thing to know the limits of the stock rods.
I was using the Ford 5.0l/302 rod as a reference to known strength vs the Nissan rod for which I don't know the limits. The rods are close to each other in size, and make, AND I have one of each rod to compare.
If your building a mild performance engine on a budget, it might be a good thing to know the limits of the stock rods.
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