How hard can you push the manual,4.6 3V?
11-28-2006, 01:53 PM
#1
2nd Gear Member
Thread Starter
Join Date: Feb 2006
Location: Pennsylvania
Posts: 167
How hard can you push the manual,4.6 3V?
In an effort to get more intimate with the car and its limitations I need some help from those with experience. CrazyAl, feel free to pipe in on this one.
A) When racing or just pushing the car hard on the street, how often, how long can/should you safely keep the tachometer in the red zone (above 6k rpm). I like playing in the meaty part of the HP/Torque curve but, I don't want to cause irreversible damage to the engine or components by overdoing it.
B) I'm not a very experienced high performance driver (this is my 3rd mustang but the others had manual tranny's and less power) but, I'm often stretching out 1st and 2nd gear to 5-6k rpm. When are you guys shifting to maximize the performance without destroying the engine?
C) I plan on upgrading the rear diff to 3.73 or 4.10 but 1st gear seems short already under WOT. This only gets worse with a higher gear ratio so, does anybody feel that 4.10 is too much gear for normal driving conditions?
thanks
A) When racing or just pushing the car hard on the street, how often, how long can/should you safely keep the tachometer in the red zone (above 6k rpm). I like playing in the meaty part of the HP/Torque curve but, I don't want to cause irreversible damage to the engine or components by overdoing it.
B) I'm not a very experienced high performance driver (this is my 3rd mustang but the others had manual tranny's and less power) but, I'm often stretching out 1st and 2nd gear to 5-6k rpm. When are you guys shifting to maximize the performance without destroying the engine?
C) I plan on upgrading the rear diff to 3.73 or 4.10 but 1st gear seems short already under WOT. This only gets worse with a higher gear ratio so, does anybody feel that 4.10 is too much gear for normal driving conditions?
thanks
11-28-2006, 03:05 PM
#2
4th Gear Member
Join Date: Aug 2006
Location: Los Angeles, California
Posts: 1,277
RE: How hard can you push the manual,4.6 3V?
Cleary,
I'll give you my 2 cents:
A) I'd keep it out of the range as much as possible, just playing with the redline. Remember, you're going to be hitting the rev limiter right above that if you push it too hard. That rev limiter is there for a reason. 5,800 to 6,000 for short periods of time should be fine.
B) In general, I shift at about 3,800 on regular driving, 4,500 - 4,600 on "spirited driving", and 5,500 - 5,700 when I get on it.
C) I'm running 3.55s, and they do seem short to me. I think 3.73 and up would only make that worse.
I'll give you my 2 cents:
A) I'd keep it out of the range as much as possible, just playing with the redline. Remember, you're going to be hitting the rev limiter right above that if you push it too hard. That rev limiter is there for a reason. 5,800 to 6,000 for short periods of time should be fine.
B) In general, I shift at about 3,800 on regular driving, 4,500 - 4,600 on "spirited driving", and 5,500 - 5,700 when I get on it.
C) I'm running 3.55s, and they do seem short to me. I think 3.73 and up would only make that worse.
11-28-2006, 03:32 PM
#3
5th Gear Member
Join Date: Nov 2006
Location: California
Posts: 4,132
RE: How hard can you push the manual,4.6 3V?
I shift at about the same however I have had my times where I hit the limiter... I think twice. Thats another reason why I'm scetchy on getting new gears. I like too but don't know how it is driving a car that revs that high... I wonder how annoying it really is - if any at all.
11-28-2006, 03:42 PM
#4
3rd Gear Member
Join Date: Jul 2006
Location:
Posts: 880
RE: How hard can you push the manual,4.6 3V?
OK,if your gonna leave your car stock then follow the advice above & shift at 6000 grand(Redline).If you are gonna flash tune your car then your shift point will change higher up the tach band.I have (For now) a canned tune(93) from Diablo and I shift from 1st to 2nd at 62-6300RPMS & from 2nd to 3rd at nearly 6800-7000RPMS!The car will handle it just fine!As long as you have the tune of course!I beat the hell out of my car and just like a girl who wants it rough!The car seems to want more of it!Hope this helps.
11-29-2006, 09:15 AM
#5
3rd Gear Member
Join Date: Aug 2006
Location: North East Texas on the Red River
Posts: 886
RE: How hard can you push the manual,4.6 3V?
I ask that you guys post here with information about your windowed blocks. I would like to see the mileage and damage details when it occurs.
Engines today are, for the most part, built much better than they were in the sixties and seventies, but everything has a limit. It will be interesting to learn from you guys what that limit is.
Good luck.
Engines today are, for the most part, built much better than they were in the sixties and seventies, but everything has a limit. It will be interesting to learn from you guys what that limit is.
Good luck.
11-29-2006, 09:53 AM
#6
5th Gear Member
Join Date: Mar 2006
Location:
Posts: 2,544
RE: How hard can you push the manual,4.6 3V?
ORIGINAL: MBDiagMan
I ask that you guys post here with information about your windowed blocks. I would like to see the mileage and damage details when it occurs.
Engines today are, for the most part, built much better than they were in the sixties and seventies, but everything has a limit. It will be interesting to learn from you guys what that limit is.
Good luck.
I ask that you guys post here with information about your windowed blocks. I would like to see the mileage and damage details when it occurs.
Engines today are, for the most part, built much better than they were in the sixties and seventies, but everything has a limit. It will be interesting to learn from you guys what that limit is.
Good luck.
I has been generally accepted that the weakest link in these engines is the rods. Generally, what kills rods is over-revving the engine. Our pistons are nothing special, but I have seen more than one 3-valve modular motor that had one or more busted rods while the pistons were A-OK. Rods typically break on the intake stroke--when the rod is pulling down the piston. The forces involved in pulling the piston down in the bore at high RPMs is astounding. Keeping away from redline is a good way to limit the loads on the rods. Raising your redline just a little bit can drastically increase the loads on the rods.
Personally, I shift around 2500-3000 during normal city driving to conserve gas and avoid cops. During spiritied driving I shift around 4500, and if I'm racing or really getting on it, I shift at 5500-5700. However, I make a careful effort to avoid revving past 6000. You don't want to hit the limiter.
11-29-2006, 11:01 AM
#7
3rd Gear Member
Join Date: Jul 2006
Location:
Posts: 880
RE: How hard can you push the manual,4.6 3V?
CrazyAl,Your talking about for stock motors right?A tuned motor will change the HP/TQ curve up the rpm band.Is that right?
ORIGINAL: CrazyAl
+1
I has been generally accepted that the weakest link in these engines is the rods. Generally, what kills rods is over-revving the engine. Our pistons are nothing special, but I have seen more than one 3-valve modular motor that had one or more busted rods while the pistons were A-OK. Rods typically break on the intake stroke--when the rod is pulling down the piston. The forces involved in pulling the piston down in the bore at high RPMs is astounding. Keeping away from redline is a good way to limit the loads on the rods. Raising your redline just a little bit can drastically increase the loads on the rods.
Personally, I shift around 2500-3000 during normal city driving to conserve gas and avoid cops. During spiritied driving I shift around 4500, and if I'm racing or really getting on it, I shift at 5500-5700. However, I make a careful effort to avoid revving past 6000. You don't want to hit the limiter.
ORIGINAL: MBDiagMan
I ask that you guys post here with information about your windowed blocks. I would like to see the mileage and damage details when it occurs.
Engines today are, for the most part, built much better than they were in the sixties and seventies, but everything has a limit. It will be interesting to learn from you guys what that limit is.
Good luck.
I ask that you guys post here with information about your windowed blocks. I would like to see the mileage and damage details when it occurs.
Engines today are, for the most part, built much better than they were in the sixties and seventies, but everything has a limit. It will be interesting to learn from you guys what that limit is.
Good luck.
I has been generally accepted that the weakest link in these engines is the rods. Generally, what kills rods is over-revving the engine. Our pistons are nothing special, but I have seen more than one 3-valve modular motor that had one or more busted rods while the pistons were A-OK. Rods typically break on the intake stroke--when the rod is pulling down the piston. The forces involved in pulling the piston down in the bore at high RPMs is astounding. Keeping away from redline is a good way to limit the loads on the rods. Raising your redline just a little bit can drastically increase the loads on the rods.
Personally, I shift around 2500-3000 during normal city driving to conserve gas and avoid cops. During spiritied driving I shift around 4500, and if I'm racing or really getting on it, I shift at 5500-5700. However, I make a careful effort to avoid revving past 6000. You don't want to hit the limiter.
11-29-2006, 11:24 AM
#8
5th Gear Member
Join Date: Mar 2006
Location:
Posts: 2,544
RE: How hard can you push the manual,4.6 3V?
ORIGINAL: Norse1974
CrazyAl,Your talking about for stock motors right?A tuned motor will change the HP/TQ curve up the rpm band.Is that right?
CrazyAl,Your talking about for stock motors right?A tuned motor will change the HP/TQ curve up the rpm band.Is that right?
Here's the details:
A connecting rod has pivots (bearings) on either end. One is the journal bearing on the crankshaft and the other is where the piston pin is. Becasue of these pivots, only tension or compression forces can be applied to the rod. The rod never sees a bending load. Now then, here's the kicker--most materials are stronger in compression than in tension. Think about it. You might have a rope that you could pull on untill it broke. But have you ever sqeezed a rope until it broke? Let's say we had a given metal bar. Suppose it could withstand 1000 lbs of force in tension before it broke. That same bar might be able to sustain a load of 1500 lbs in compression. This applies to rods too. The rods are stronger under compression than they are under tension. Of the 4 strokes in a 4-stroke engine, three of them place the rods under compression: the power stroke where the expanding gas is pushing the piston down, as well as the exhaust and compression strokes where the rod is pushing the piston upwards. However, on the intake stroke the rod has to pull the piston down. This is the weak spot.
A piston doesn't weigh a whole lot, but when your engine is running at 6,000 RPM (that's 100 revs per second), the piston has to travel the length of the engine's stroke in a very short time. Becasue it has to move so fast the tension in the rod is extremely high...and this is when rods tend to break because it's typically the "weak link" in the system.
You'll notice that this is more or less indipendant of the HP of the engine. Moral of the story--watch your RPMs. Race engines that are built for high-rpm duty have super-lightweight pistons, which are designed to reduce the loading on the rods in this situation. They also have stronger rods, of course.
11-29-2006, 03:14 PM
#9
2nd Gear Member
Join Date: Feb 2006
Location:
Posts: 361
RE: How hard can you push the manual,4.6 3V?
DUDE - nice write-up - thanks!!
ORIGINAL: CrazyAl
You're right that a modified motor tends to shift the powerband into the higher RPMs. However, that doesn't change the fact that rods tend to break on the intake stroke at high RPM.
Here's the details:
A connecting rod has pivots (bearings) on either end. One is the journal bearing on the crankshaft and the other is where the piston pin is. Becasue of these pivots, only tension or compression forces can be applied to the rod. The rod never sees a bending load. Now then, here's the kicker--most materials are stronger in compression than in tension. Think about it. You might have a rope that you could pull on untill it broke. But have you ever sqeezed a rope until it broke? Let's say we had a given metal bar. Suppose it could withstand 1000 lbs of force in tension before it broke. That same bar might be able to sustain a load of 1500 lbs in compression. This applies to rods too. The rods are stronger under compression than they are under tension. Of the 4 strokes in a 4-stroke engine, three of them place the rods under compression: the power stroke where the expanding gas is pushing the piston down, as well as the exhaust and compression strokes where the rod is pushing the piston upwards. However, on the intake stroke the rod has to pull the piston down. This is the weak spot.
A piston doesn't weigh a whole lot, but when your engine is running at 6,000 RPM (that's 100 revs per second), the piston has to travel the length of the engine's stroke in a very short time. Becasue it has to move so fast the tension in the rod is extremely high...and this is when rods tend to break because it's typically the "weak link" in the system.
You'll notice that this is more or less indipendant of the HP of the engine. Moral of the story--watch your RPMs. Race engines that are built for high-rpm duty have super-lightweight pistons, which are designed to reduce the loading on the rods in this situation. They also have stronger rods, of course.
ORIGINAL: Norse1974
CrazyAl,Your talking about for stock motors right?A tuned motor will change the HP/TQ curve up the rpm band.Is that right?
CrazyAl,Your talking about for stock motors right?A tuned motor will change the HP/TQ curve up the rpm band.Is that right?
Here's the details:
A connecting rod has pivots (bearings) on either end. One is the journal bearing on the crankshaft and the other is where the piston pin is. Becasue of these pivots, only tension or compression forces can be applied to the rod. The rod never sees a bending load. Now then, here's the kicker--most materials are stronger in compression than in tension. Think about it. You might have a rope that you could pull on untill it broke. But have you ever sqeezed a rope until it broke? Let's say we had a given metal bar. Suppose it could withstand 1000 lbs of force in tension before it broke. That same bar might be able to sustain a load of 1500 lbs in compression. This applies to rods too. The rods are stronger under compression than they are under tension. Of the 4 strokes in a 4-stroke engine, three of them place the rods under compression: the power stroke where the expanding gas is pushing the piston down, as well as the exhaust and compression strokes where the rod is pushing the piston upwards. However, on the intake stroke the rod has to pull the piston down. This is the weak spot.
A piston doesn't weigh a whole lot, but when your engine is running at 6,000 RPM (that's 100 revs per second), the piston has to travel the length of the engine's stroke in a very short time. Becasue it has to move so fast the tension in the rod is extremely high...and this is when rods tend to break because it's typically the "weak link" in the system.
You'll notice that this is more or less indipendant of the HP of the engine. Moral of the story--watch your RPMs. Race engines that are built for high-rpm duty have super-lightweight pistons, which are designed to reduce the loading on the rods in this situation. They also have stronger rods, of course.
04-22-2013, 08:48 PM
#10
Join Date: Apr 2013
Location: florida
Posts: 4
Hello all,
First off I'm new to this forum and just purchased my first Ford Mustang. I've had the car for a few weeks now and have already added intake and exhaust. I have many more plans for my new baby. My question is......What can I get away with, power wise, before I need to build a stronger bottom end? I have a cai new throttle body, long tube headers, x-pipe, and exhaust. I want the frpp intake manifold, hot rod cams, and frpp stage 1 heads. Beyond that I don't know what the stock block can handle. Any pointers would be appreciated. Thanks in advance!
First off I'm new to this forum and just purchased my first Ford Mustang. I've had the car for a few weeks now and have already added intake and exhaust. I have many more plans for my new baby. My question is......What can I get away with, power wise, before I need to build a stronger bottom end? I have a cai new throttle body, long tube headers, x-pipe, and exhaust. I want the frpp intake manifold, hot rod cams, and frpp stage 1 heads. Beyond that I don't know what the stock block can handle. Any pointers would be appreciated. Thanks in advance!