Stock 4.6 block HP rating
08-19-2010, 08:29 AM
#1
2nd Gear Member
Thread Starter
Join Date: Jan 2005
Location: Hampton, Va
Posts: 325
Stock 4.6 block HP rating
I have an 02 Mustang GT, with a stock 4.6 2v block. Its full bolt on, with patriot stage 2 heads, stage 2 comp cams, and full exhaust. I recently put on an F1 procharger setup. I went and got it tuned, and she put down 465hp. The tuner said it was on a conservative tune because the block was, "on the doorstep of destruction." I'm curious at to what my block is rated to HP wise. Thanks for any help!
08-19-2010, 08:32 AM
#2
Underboss
Join Date: Jan 2006
Location: Helaware
Posts: 20,273
I have an 02 Mustang GT, with a stock 4.6 2v block. Its full bolt on, with patriot stage 2 heads, stage 2 comp cams, and full exhaust. I recently put on an F1 procharger setup. I went and got it tuned, and she put down 465hp. The tuner said it was on a conservative tune because the block was, "on the doorstep of destruction." I'm curious at to what my block is rated to HP wise. Thanks for any help!
08-19-2010, 11:13 AM
#4
4th Gear Member
Join Date: Jul 2008
Location: NC
Posts: 1,956
Some people blow up at 400RWHP/TQ some people run for 3 years at 450 until it blows or they forge it. Your tuner is absolutely right, your "cruisin' for a bruisin," "playing with fire" whatever you wanna call it. There is no definite magical number at which it blows, but you're certainly in range to. You have the capability to blow that engine to smithereens with the blower alone and youve got a lot more work done than that. I would back the tune down to 400-415 until you have it forged.
08-19-2010, 11:16 AM
#5
5th Gear Member
Join Date: Aug 2007
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^ your question doesnt make sense. both are the same end result. you need forged internals, doesnt matter which road you go...just one may be cheaper than the other.
ford rated the rods in this car to 475 crank horsepower, the pistons are slightly higher, and the crank is said to be good to like 600-700. with your power numbers, you are FAR exceeding any power level that can be considered "safe". that being said, you MAY be able to keep that motor as is for a good long time if you have a factory freak. but if your wanting to play the odds, they are not in favor of your motor lasting.
ford rated the rods in this car to 475 crank horsepower, the pistons are slightly higher, and the crank is said to be good to like 600-700. with your power numbers, you are FAR exceeding any power level that can be considered "safe". that being said, you MAY be able to keep that motor as is for a good long time if you have a factory freak. but if your wanting to play the odds, they are not in favor of your motor lasting.
08-21-2010, 03:11 PM
#6
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
^ your question doesnt make sense. both are the same end result. you need forged internals, doesnt matter which road you go...just one may be cheaper than the other.
ford rated the rods in this car to 475 crank horsepower, the pistons are slightly higher, and the crank is said to be good to like 600-700. with your power numbers, you are FAR exceeding any power level that can be considered "safe". that being said, you MAY be able to keep that motor as is for a good long time if you have a factory freak. but if your wanting to play the odds, they are not in favor of your motor lasting.
ford rated the rods in this car to 475 crank horsepower, the pistons are slightly higher, and the crank is said to be good to like 600-700. with your power numbers, you are FAR exceeding any power level that can be considered "safe". that being said, you MAY be able to keep that motor as is for a good long time if you have a factory freak. but if your wanting to play the odds, they are not in favor of your motor lasting.
Consider that they used a forged crankshaft and rods in the 390fwHP '03 qnd '04 Cobras. They didn't do this just to spend more money, it was because they didn't think the cast steel crank and powdered metal rods used in the GT and Mach 1 hold up.
420rwHP (≈480fwHP) is the practical limit for the 2V's stock internals, and that is 23% more than Ford felt they were good for, as compared to the Cobra...
08-21-2010, 05:14 PM
#7
5th Gear Member
Join Date: Aug 2007
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the cobra crank has always been used in the 4v's (minus the automatic mach1 which only redlines at 5800rpm) ignoring the HP numbers (even down to the sn95 cobras making a whole 305 crank horsepower), because its balanced to spin higher than the cast GT crank. the GT crank is actually pretty strong and can hold some nice numbers, but its not balanced to spin to 7k like the stock 4v's do (since 2v heads dont flow, there is no reason to even try to spin to 7k without doing some major work). MMR even sells the MMR600 shortblock with the cast GT crank, which they guarantee for 600hp. the cobra crank is an additional cost. no one uses the GT crank though because they want to spin the motor higher than 5800rpm once you've got some heads, cams, and a ton of boost.
there would have been a huge liability using the GT rods and pistons in the cobra yes, because they possibly (and in all likeliness) would have had a TON of warranty work from blown motors. we see people on here all the time blowing motors at, over, even below the "safe" 400rwhp range. ford was smart enough not to gamble losing millions of dollars to save a few thousand dollars on the rods and pistons. the cobra crank would have been used anyways to keep the 7krpm redline, it has always been used for that reason.
i dont think the rods are safe even at 400rwhp. i tell that to people all the time who ask what the "safe limit" for hp is. thats why i always put "safe" in quotes. the bottom line with the 4.6 is once you start boosting, nomatter how high or low, there is no telling how long the motor will last because they were not designed to handle boost. and at 465rwhp, i dont see the ops motor lasting too long. BUT there is a guy on another forum who atleast claims he is running over 500rwhp on his stock 4.6, but i dont think there has ever been any proof other than dyno numbers (no proof of what kind of motor he actually has).
there would have been a huge liability using the GT rods and pistons in the cobra yes, because they possibly (and in all likeliness) would have had a TON of warranty work from blown motors. we see people on here all the time blowing motors at, over, even below the "safe" 400rwhp range. ford was smart enough not to gamble losing millions of dollars to save a few thousand dollars on the rods and pistons. the cobra crank would have been used anyways to keep the 7krpm redline, it has always been used for that reason.
i dont think the rods are safe even at 400rwhp. i tell that to people all the time who ask what the "safe limit" for hp is. thats why i always put "safe" in quotes. the bottom line with the 4.6 is once you start boosting, nomatter how high or low, there is no telling how long the motor will last because they were not designed to handle boost. and at 465rwhp, i dont see the ops motor lasting too long. BUT there is a guy on another forum who atleast claims he is running over 500rwhp on his stock 4.6, but i dont think there has ever been any proof other than dyno numbers (no proof of what kind of motor he actually has).
Last edited by MU71L4710N; 08-21-2010 at 05:18 PM.
08-22-2010, 02:47 PM
#10
3rd Gear Member
Join Date: Jan 2009
Location: Florida
Posts: 570
The guys in NMRA have proved both of these wrong, Brandon Alsept spins the stock cast crank to 9500RPM and Bill Putnam ran the stock 2V PI heads to 7000RPM shifts in capturing the stock 2V longblock plus cams record of 11.98@113MPH.
As for the OP original question yes the tuner is correct, 400RWHP is 99% safe, 450RWHP is 50/50 and 500 is probably around 10% safe. Its the stock tight piston ring gap that usually fails first with a boosted motor. If the ends butt up they will break the ringland on the piston.