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

General engine tech -- Drag Racing to Circle Track

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

Post by vortecpro » Sun Sep 17, 2017 6:01 pm

I'am going to ask the same question I asked on the Chevelle forum.


"Which engine is faster down a dragstrip and why"




A 427 that makes 600 HP @ 6200 RPM
A 427 that makes 600 HP @ 7100 RPM

?
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Re: Which Is Faster

Post by MTENGINES » Sun Sep 17, 2017 6:05 pm

More rpm is more gear.. more gear is torque multiplication. .

digger
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Re: Which Is Faster

Post by digger » Sun Sep 17, 2017 6:26 pm

if they had a cvt then basically the same but the lower rpm engine might have less losses in the transmission and more to the wheels but not much.

In reality you need to compare the hp curves not the peak of you want to get anywhere
Last edited by digger on Sun Sep 17, 2017 6:29 pm, edited 1 time in total.

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Re: Which Is Faster

Post by JoePorting » Sun Sep 17, 2017 6:28 pm

I would say the 427 that makes 600 hp at 6200 rpms because that suggests it might make 700 hp at 7100 rpms.
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Re: Which Is Faster

Post by DCal » Sun Sep 17, 2017 6:31 pm

RPM is wheel speed and wheel is MPH, look at Warren Johnson's record. In his heyday he consistently had the fastest car. NHRA has limited the rpm and now 210mph is considered fast, of course the rest of the combo has to be adjusted to work as a package.

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Re: Which Is Faster

Post by vortecpro » Sun Sep 17, 2017 6:52 pm

Theres two answers on here I like a lot =D> . Same exact curve except one is 900 RPM higher.
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Re: Which Is Faster

Post by peejay » Sun Sep 17, 2017 6:55 pm

Whichever one is geared appropriately to the powerband will have a better ET, but the MPH will probably be the same no matter what.

More likely, if the engines are the same displacement, they probably make about the same amount of torque, so they can't be "the same curve". I am going to assume that the higher revving engine sacrifices a little bit of peak torque for a softer yet longer powerband. So the higher revving one probably is putting down more average HP in each gear, assuming that the one with a lower RPM horsepower peak lays down early.

Power curves are not peak numbers, but you can infer a lot...

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Re: Which Is Faster

Post by bigjoe1 » Sun Sep 17, 2017 7:24 pm

I like the higher RPM engine every time



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Re: Which Is Faster

Post by ptuomov » Sun Sep 17, 2017 8:13 pm

vortecpro wrote:Theres two answers on here I like a lot =D> . Same exact curve except one is 900 RPM higher.
Shifted right by adding a constant factor to rpm or by multiplying rpm by a constant factor? In the latter case, I'd say I couldn't guess which would be faster. Equally fast up to my abilities.
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Re: Which Is Faster

Post by Geoff2 » Mon Sep 18, 2017 5:16 am

I suspect 600 hp @ 6200 will be faster. The engine making 600 hp@ 7100 will be making less hp @ 6200....

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Re: Which Is Faster

Post by paulzig » Mon Sep 18, 2017 5:43 am

Geoff2 wrote:I suspect 600 hp @ 6200 will be faster. The engine making 600 hp@ 7100 will be making less hp @ 6200....

But the 600HP@6200 makes less HP at 7100RPM ....

If you shift the 7100RPM engine at 7800 then it wont fall back to 6200RPM on the shift.. So does what it makes at 6200 have any real value?

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Re: Which Is Faster

Post by gvx » Mon Sep 18, 2017 5:55 am

The engine making more power at lower RPM has to be making more average torque. If the chassis is the same for both then whichever engine the chassis is set up for will work best. If you optimize the chassis for each engine, the lower RPM engine making the most average torque will be the fastest. Although the difference will be tiny. Assuming the lower RPM engine has more compression? Raising the peak power rpm, it will make more HP so there will be the faster of the two
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Re: Which Is Faster

Post by BILL-C » Mon Sep 18, 2017 6:21 am

The higher rpm peak version 427 , when geared properly, will make car faster. More power cycles in the same distance, so more work gets done.
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Re: Which Is Faster

Post by hoffman900 » Mon Sep 18, 2017 8:13 am

Higher rpm. Every time (assuming both versions are optiminly geared for their respective power bands).
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Re: Which Is Faster

Post by KnightEngines » Mon Sep 18, 2017 10:07 am

Whichever has gear & converter to keep the motor closest to peak hp rpm for the whole pass.
Or whichever makes more average hp in the range dictated by gear & converter.

Rpm makes no difference, but usually the motor that peaks at higher rpm will be easier to keep near peak hp.

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