Which Is Faster - 600hp@6200 or 600hp@7100

General engine tech -- Drag Racing to Circle Track

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GARY C
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Re: Which Is Faster

Post by GARY C » Tue Sep 19, 2017 12:13 am

So a 357 making 530 horse at 7700 out runs a 331 making 529 horse at 6500 regardless of combo or the fact that the 331 makes 81 more ft lbs?

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Re: Which Is Faster

Post by MTENGINES » Tue Sep 19, 2017 12:24 am

GARY C wrote:So a 357 making 530 horse at 7700 out runs a 331 making 529 horse at 6500 regardless of combo or the fact that the 331 makes 81 more ft lbs?
We usually don't race at peak torque. Most drag racing engines I do, the stall ends up being around 500rpm less than peak horsepower rpm of they are NA. Who cares about torque. An engine that loses torque the slowest usually wins.. because it will rpm.

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Re: Which Is Faster

Post by cgarb » Tue Sep 19, 2017 12:46 am

Playing the devils advocate here...how is it that there are fast diesel powered trucks then? Does rpm have that much to do with it?

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Re: Which Is Faster

Post by GARY C » Tue Sep 19, 2017 1:16 am

MTENGINES wrote:
GARY C wrote:So a 357 making 530 horse at 7700 out runs a 331 making 529 horse at 6500 regardless of combo or the fact that the 331 makes 81 more ft lbs?
We usually don't race at peak torque. Most drag racing engines I do, the stall ends up being around 500rpm less than peak horsepower rpm of they are NA. Who cares about torque. An engine that loses torque the slowest usually wins.. because it will rpm.
So you run the correct gear and converter for each combo...Do you really think the one with 80 ft lbs less tq is going to have a better tq curve some where? Anywhere in its rpm range? If it's down 80 ft lbs at peak it's down everywhere by a Lot!

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Re: Which Is Faster

Post by In-Tech » Tue Sep 19, 2017 1:40 am

Trotter: Alright, alright. Now, Miss Vito, being an expert on general automotive knowledge, can you tell me what would be the correct ignition timing be on a 1955 Bellaire Chevrolet with a 327 cubic engine and a 4-barrel carburetor.

Ms. Vito: It's a bullshit question.

Trotter: Does that mean that you can't answer it?

Ms. Vito: It's a bullshit question. It's impossible to answer.

Trotter: It's impossible because you don't know the answer!

Ms. Vito: Nobody could answer that question!

Trotter: Your Honor, I move to disqualify Miss Vito as a expert witness.

Judge Haller: Can you answer the question?

Ms. Vito: No. It is a trick question.

Judge Haller: Why is it a trick question?

Vincent Gambini: [to his clients] Watch this.

Ms. Vito: 'Cause Chevy didn't make a 327 in '55. The 327 didn't come out til '62. And it wasn't offered in the Bellaire with the 4-barrel carburetor til '64. However, in 1964 the correct ignition timing would be 4 degrees before top dead center.
Heat is energy, energy is horsepower...but you gotta control the heat.
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The Radius Kid
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Re: Which Is Faster

Post by The Radius Kid » Tue Sep 19, 2017 1:43 am

cgarb wrote:Playing the devils advocate here...how is it that there are fast diesel powered trucks then? Does rpm have that much to do with it?
This what I was getting at earlier.Good point.
The Nazis didn't lose WWII,they just changed uniforms.Now they run the place.

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Re: Which Is Faster

Post by cgarb » Tue Sep 19, 2017 1:52 am

My Cousin Vinny...lol. Cool fact, I grew up about 3 miles from Fred Gwynne's home place. The judge in that movie. Let me tell you he was a very large man, very friendly but intimidating to an 8 year old...lol. Took me a while to even talk to him when he would walk into the local store.

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Re: Which Is Faster

Post by GARY C » Tue Sep 19, 2017 1:56 am

The Radius Kid wrote:
cgarb wrote:Playing the devils advocate here...how is it that there are fast diesel powered trucks then? Does rpm have that much to do with it?
This what I was getting at earlier.Good point.
This is along the lines of what I am thinking, It's a power band over a given RPM and the rest of the combo is built to work in that given range, you see the same thing in turbo development as well as progressive nitrous systems.

Although I could play devils advocate to my own argument in regards to my 72 Nova and my 377 vs 306 engine combo.

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Re: Which Is Faster

Post by GARY C » Tue Sep 19, 2017 1:58 am

In-Tech wrote:Trotter: Alright, alright. Now, Miss Vito, being an expert on general automotive knowledge, can you tell me what would be the correct ignition timing be on a 1955 Bellaire Chevrolet with a 327 cubic engine and a 4-barrel carburetor.

Ms. Vito: It's a bullshit question.

Trotter: Does that mean that you can't answer it?

Ms. Vito: It's a bullshit question. It's impossible to answer.

Trotter: It's impossible because you don't know the answer!

Ms. Vito: Nobody could answer that question!

Trotter: Your Honor, I move to disqualify Miss Vito as a expert witness.

Judge Haller: Can you answer the question?

Ms. Vito: No. It is a trick question.

Judge Haller: Why is it a trick question?

Vincent Gambini: [to his clients] Watch this.

Ms. Vito: 'Cause Chevy didn't make a 327 in '55. The 327 didn't come out til '62. And it wasn't offered in the Bellaire with the 4-barrel carburetor til '64. However, in 1964 the correct ignition timing would be 4 degrees before top dead center.
So what do you consider a BS question? This thread?

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Post by The Radius Kid » Tue Sep 19, 2017 2:23 am

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Last edited by The Radius Kid on Tue Sep 19, 2017 2:27 am, edited 3 times in total.
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Re: Which Is Faster

Post by The Radius Kid » Tue Sep 19, 2017 2:23 am

GARY C wrote:
The Radius Kid wrote:
cgarb wrote:Playing the devils advocate here...how is it that there are fast diesel powered trucks then? Does rpm have that much to do with it?
This what I was getting at earlier.Good point.
This is along the lines of what I am thinking, It's a power band over a given RPM and the rest of the combo is built to work in that given range, you see the same thing in turbo development as well as progressive nitrous systems.

Although I could play devils advocate to my own argument in regards to my 72 Nova and my 377 vs 306 engine combo.
I'm thinking it's along the lines of maintaining steady power delivery.
I remember reading years ago that pro stocks had heavy fly wheels ... 60 pounds or so.
They said that even if the engine stalled at launch,the car would still launch for 60 ft or so because of the flywheel mass.
That's lot of inertia because of mass and rpm.
Given the two engines in the O/P are the same except for rpm,that would give the higher rpm engine more rotational inertia at peak power.
IIRC: It should be (7100/6200) squared,which gives the higher rpm engine an approximately 30 percent higher rotational inertia at the shift point.
Sound about right?
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Re: Which Is Faster

Post by GARY C » Tue Sep 19, 2017 2:28 am

So would an engine with a better tq curve not take advantage of the fly wheel effect?

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Re: Which Is Faster

Post by The Radius Kid » Tue Sep 19, 2017 2:31 am

GARY C wrote:So would an engine with a better tq curve not take advantage of the fly wheel effect?
I would think so,but it would depend on where the shift occurs.
IIRC,most guys shift near peak torque as a general rule.
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Re: Which Is Faster

Post by GARY C » Tue Sep 19, 2017 2:36 am

The Radius Kid wrote:
GARY C wrote:So would an engine with a better tq curve not take advantage of the fly wheel effect?
I would think so,but it would depend on where the shift occurs.
IIRC,most guys shift near peak torque as a general rule.
Forgive me I don't know what IIRC means but I thought you normally shift about 700 rpm past peak horse power?

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Re: Which Is Faster

Post by digger » Tue Sep 19, 2017 2:45 am

Where did the op say there was a converter ? I prefer manual myself

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