Shift points and hp peak...
09-13-2011, 06:06 PM
#21
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So it's dumb to tell puck he's off his rocker to claim bolt-on's influence shift points? Whatever there, brohster. Make sure to let me know when you head to Cecil.
If you have a dyno graph of your power peak then, as stated by the moral one, go to the track and work on different shift points around said power peak.
Last edited by SS RRR; 09-13-2011 at 06:11 PM.
09-13-2011, 06:36 PM
#22
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According to my pitiful stock dyno, my shift point BONE STOCK should have been 5700rpm.
If I shifted based off my torque peak, I'd be shifting in the 4700 range. Wow, no.
If I shifted based off my torque peak, I'd be shifting in the 4700 range. Wow, no.
09-13-2011, 06:49 PM
#23
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09-13-2011, 07:08 PM
#24
LSWHO can you make up your mind about what you are even arguing about??? You are all over the place.
First you talk about stall rating and shift extension, then you talk about shift points. They are totally different things, and I don't know who was the first to mention shifting at peak TQ in here but it sure as hell wasn't me.
Once gain, I clearly said to spec your stall 300-500 rpm before peak TQ (STALL, NOT SHIFT POINT) and shift 300-500 after peak HP...as a starting point. Is that so hard to understand?
In the VERY FIRST response to this thread I said that it all depends on your vehicle, and you are asking for blanket rules and statements. Like everyone else said, go to the track and test it.
Pick a question and ask it, don't ask vague topics for discussion sake then change what you are talking about 4 times throughout the thread.
Sounds like the problem is that people are still treating TQ and HP as two totally different entities, and arguing which one is better, when they are one and the same. If you have the RPMs, you are doing more work in a set period of time. If you can't spin high, spec your combo to take advantage of your TQ.
Nope. Drag racing is about GEARING and RPMs to make use of your TQ. All other things being equal a car with a broad, flat TQ curve will outperform a peaky high HP car with horrible low and mid range. Ever seen a 600rwhp import run a 12? Its not because of its lack of HP, its because it has not been geared to take advantage of its engines short peaky powerband. On the other side of the spectrum, an engine that should have a nice broad TQ curve...like a solid roller 396 for example...can also run 12s if the rest of the combo is not properly matched. But you know that already 
.
First you talk about stall rating and shift extension, then you talk about shift points. They are totally different things, and I don't know who was the first to mention shifting at peak TQ in here but it sure as hell wasn't me.
Once gain, I clearly said to spec your stall 300-500 rpm before peak TQ (STALL, NOT SHIFT POINT) and shift 300-500 after peak HP...as a starting point. Is that so hard to understand?
In the VERY FIRST response to this thread I said that it all depends on your vehicle, and you are asking for blanket rules and statements. Like everyone else said, go to the track and test it.
Pick a question and ask it, don't ask vague topics for discussion sake then change what you are talking about 4 times throughout the thread.
Sounds like the problem is that people are still treating TQ and HP as two totally different entities, and arguing which one is better, when they are one and the same. If you have the RPMs, you are doing more work in a set period of time. If you can't spin high, spec your combo to take advantage of your TQ.
.
09-13-2011, 07:13 PM
#25
Horsepower is a direct relationship to an engine's ability to do work.
Torque is an engine's advantage to do that work.
They are both equally important.
You can't have one and not another; unless you are freeze frame racing.
Think of it like this: Horsepower is an engines torque in a time related format.
What moves you down the track isn't torque or horsepower by itself, but as a combination of leverage to do work in a certain amount of time.
You want to have more of BOTH...
To add to a little more Food for thought.... work is what is required to move the car down the track. Now lets say that your torque curve drops 50 lb/ft at peak Hp. but you're up 50 hp from peak tq. Now does that mean that the car is doing less work??? NO. It could still be making more work.
When a piston is coming down in the combustion stroke makes power it makes only so much torque for that one cycle. so if you make 30lb/ft of torque on that stroke and you only get 3 strokes per second you only made 90lb/ft/sec. Now say that any more strokes/sec will make less lb/ft per stroke. Now you only make 25lb/ft per stroke. But now you get 4 strokes per second. So you now make 100lb/ft/sec. So which is better? these are just an example and don't reflect actual numbers for a vehicle, but this illustrates the HP/torque/work relationship.
like joelster said, take it to the track and test it. That is the only way to get the best shift point.
Torque is an engine's advantage to do that work.
They are both equally important.
You can't have one and not another; unless you are freeze frame racing.
Think of it like this: Horsepower is an engines torque in a time related format.
What moves you down the track isn't torque or horsepower by itself, but as a combination of leverage to do work in a certain amount of time.
You want to have more of BOTH...
To add to a little more Food for thought.... work is what is required to move the car down the track. Now lets say that your torque curve drops 50 lb/ft at peak Hp. but you're up 50 hp from peak tq. Now does that mean that the car is doing less work??? NO. It could still be making more work.
When a piston is coming down in the combustion stroke makes power it makes only so much torque for that one cycle. so if you make 30lb/ft of torque on that stroke and you only get 3 strokes per second you only made 90lb/ft/sec. Now say that any more strokes/sec will make less lb/ft per stroke. Now you only make 25lb/ft per stroke. But now you get 4 strokes per second. So you now make 100lb/ft/sec. So which is better? these are just an example and don't reflect actual numbers for a vehicle, but this illustrates the HP/torque/work relationship.
like joelster said, take it to the track and test it. That is the only way to get the best shift point.
. I like the watermill example used in the link posted too...it makes it really easy to understand the relationship of TQ and HP. The Case For Horsepower
OK. If torque is so all-fired important, why do we care about horsepower?
Because (to quote a friend), "It is better to make torque at high rpm than at low rpm, because you can take advantage of *gearing*.
For an extreme example of this, I'll leave carland for a moment, and describe a waterwheel I got to watch awhile ago. This was a pretty massive wheel (built a couple of hundred years ago), rotating lazily on a shaft which was connected to the works inside a flour mill. Working some things out from what the people in the mill said, I was able to determine that the wheel typically generated about 2600(!) foot pounds of torque. I had clocked its speed, and determined that it was rotating at about 12 rpm. If we hooked that wheel to, say, the drivewheels of a car, that car would go from zero to twelve rpm in a flash, and the waterwheel would hardly notice :-).
On the other hand, twelve rpm of the drivewheels is around one mph for the average car, and, in order to go faster, we'd need to gear it up. To get to 60 mph would require gearing the wheel up enough so that it would be effectively making a little over 43 foot pounds of torque at the output, which is not only a relatively small amount, it's less than what the average car would need in order to actually get to 60. Applying the conversion formula gives us the facts on this. Twelve times twenty six hundred, over five thousand two hundred fifty two gives us:
6 HP.
Oops. Now we see the rest of the story. While it's clearly true that the water wheel can exert a *bunch* of force, its *power* (ability to do work over time) is severely limited.
OK. If torque is so all-fired important, why do we care about horsepower?
Because (to quote a friend), "It is better to make torque at high rpm than at low rpm, because you can take advantage of *gearing*.
For an extreme example of this, I'll leave carland for a moment, and describe a waterwheel I got to watch awhile ago. This was a pretty massive wheel (built a couple of hundred years ago), rotating lazily on a shaft which was connected to the works inside a flour mill. Working some things out from what the people in the mill said, I was able to determine that the wheel typically generated about 2600(!) foot pounds of torque. I had clocked its speed, and determined that it was rotating at about 12 rpm. If we hooked that wheel to, say, the drivewheels of a car, that car would go from zero to twelve rpm in a flash, and the waterwheel would hardly notice :-).
On the other hand, twelve rpm of the drivewheels is around one mph for the average car, and, in order to go faster, we'd need to gear it up. To get to 60 mph would require gearing the wheel up enough so that it would be effectively making a little over 43 foot pounds of torque at the output, which is not only a relatively small amount, it's less than what the average car would need in order to actually get to 60. Applying the conversion formula gives us the facts on this. Twelve times twenty six hundred, over five thousand two hundred fifty two gives us:
6 HP.
Oops. Now we see the rest of the story. While it's clearly true that the water wheel can exert a *bunch* of force, its *power* (ability to do work over time) is severely limited.
09-13-2011, 07:38 PM
#26
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Nope. Drag racing is about GEARING and RPMs to make use of your TQ. All other things being equal a car with a broad, flat TQ curve will outperform a peaky high HP car with horrible low and mid range. Ever seen a 600rwhp import run a 12? Its not because of its lack of HP, its because it has not been geared to take advantage of its engines short peaky powerband. On the other side of the spectrum, an engine that should have a nice broad TQ curve...like a solid roller 396 for example...can also run 12s if the rest of the combo is not properly matched. But you know that already .
.You are absolutely right about GEARING and RPM. It's about gearing and RPM to complement power peak. Of course it's great to have more torque for more power at a given RPM. That's understood. Having a combination with improper gearing means it is not making use of the power curve. This happened to me with two combos. I had 4.10's in a LPE setup w/ a 211 cam, was running 114.2mph consistently. Changed to 3.73's and started running 115.5mph with improved ET's. Why? Because the 4.10's were taking the engine far past power peak, car was slowing down before going through the traps. The 3.73's had the engine just at or after power peak through the traps. Same thing with my mismatched combo you have such a hard on for. Running 3.73 gears and a 6800rpm power peak the engine was coming nowhere close to the power peak, which yielded consistent 11.7 @ 120mph runs. 4.56's were installed and the ET's vastly improved as well as running close to 3mph faster. The gearing chosen was done using a power peak reference. Not torque.
What the subject is about is figuring out shift points at a given RPM. Not to go into some blowhard explanation how torque should be factored into shift points. That's retarded, including your bolt-on shift point change theory. For information sake, can you please explain how mere bolt-on's can influence shift points? Perhaps change power peak to a different RPM?
Last edited by SS RRR; 09-13-2011 at 08:00 PM.
09-13-2011, 08:01 PM
#27
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I have ONLY been talking about shift points vs hp peak. Try reading my posts.
If this thread is too much for you puck, maybe go away. I misread your after peak hp part. Get over it. christ.
If this thread is too much for you puck, maybe go away. I misread your after peak hp part. Get over it. christ.
09-13-2011, 08:06 PM
#28
There's not need to start in with your pretentious bullshit.
You are absolutely right about GEARING and RPM. It's about gearing and RPM to complement power peak. Of course it's great to have more torque for more power at a given RPM. That's understood. Having a combination with improper gearing means it is not making use of the power curve. This happened to me with two combos. I had 4.10's in a LPE setup w/ a 211 cam, was running 114.2mph consistently. Changed to 3.73's and started running 115.5mph with improved ET's. Why? Because the 4.10's were taking the engine far past power peak, car was slowing down before going through the traps. The 3.73's had the engine just at or after power peak through the traps. Same thing with my mismatched combo you have such a hard on for. Running 3.73 gears and a 6800rpm power peak the engine was coming nowhere close to the power peak, which yielded consistent 11.7 @ 120mph runs. 4.56's were installed and the ET's vastly improved as well as running close to 3mph faster. The gearing chosen was done using a power peak reference. Not torque.
What the subject is about is figuring out shift points at a given RPM. Not to go into some diatribe about how torque should be factored into shift points. That's retarded, including your bolt-on shift point change theory. For information sake, can you please explain how mere bolt-on's can influence shift points? Perhaps change power peak to a different RPM?
You are absolutely right about GEARING and RPM. It's about gearing and RPM to complement power peak. Of course it's great to have more torque for more power at a given RPM. That's understood. Having a combination with improper gearing means it is not making use of the power curve. This happened to me with two combos. I had 4.10's in a LPE setup w/ a 211 cam, was running 114.2mph consistently. Changed to 3.73's and started running 115.5mph with improved ET's. Why? Because the 4.10's were taking the engine far past power peak, car was slowing down before going through the traps. The 3.73's had the engine just at or after power peak through the traps. Same thing with my mismatched combo you have such a hard on for. Running 3.73 gears and a 6800rpm power peak the engine was coming nowhere close to the power peak, which yielded consistent 11.7 @ 120mph runs. 4.56's were installed and the ET's vastly improved as well as running close to 3mph faster. The gearing chosen was done using a power peak reference. Not torque.
What the subject is about is figuring out shift points at a given RPM. Not to go into some diatribe about how torque should be factored into shift points. That's retarded, including your bolt-on shift point change theory. For information sake, can you please explain how mere bolt-on's can influence shift points? Perhaps change power peak to a different RPM?
Again, I think the confusion comes from mixing up STALL suggestions (referencing engine TQ) with SHIFT POINTS(referencing peak HP). Two different things.
Even bolt-ons like intake, 1.6rrs, and exhaust besides giving a bit more power also give you more rpms.
I don't have back to back dyno's, but I'm sure a header/exhaust/intake/1.6rr/tune car will peak later then a bone stock LT1.
I love how these threads get so out of hand with multiple people arguing the same things just worded differently.
09-13-2011, 08:07 PM
#29
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I never asked for a blanket rule you illiterate ***. I asked WHY people specifically say just after hp peak 4-500rpm. I'm so done with this site you retards can't read for ****.
09-13-2011, 08:34 PM
#30
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Do you have a chemical imbalance of some sort? Maybe we are saying the same thing, but they way you are going about it is some of the most overcomplicated crap I've ever read. I guess I am also thrown off with the outlandish statement that LT1's should be shifting at 5000 to 5200rpm. That's complete horse ****.
I don't have back to back dyno's, but I'm sure a header/exhaust/intake/1.6rr/tune car will peak later then a bone stock LT1.
Oh, u mad?
Last edited by SS RRR; 09-13-2011 at 09:01 PM.
09-13-2011, 09:18 PM
#32
09-14-2011, 06:44 AM
#34
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I am still under the impression you don't believe there is a such thing as horsepower. That is puzzling. If that's the case, how can you figure out **** points?
Maybe I should make myself clearer using your logic:
Drag racing is all about choosing shift points derived from that measurement thingy of torque over time. Since horsie powers does not exist, we'll just substitute it with longer words to look smrtr1111
Horsiepowers= The forbidden term
Is that better?
Maybe I should make myself clearer using your logic:
Drag racing is all about choosing shift points derived from that measurement thingy of torque over time. Since horsie powers does not exist, we'll just substitute it with longer words to look smrtr1111
Horsiepowers= The forbidden term
Is that better?
