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Rwhp vs engine dyno

Started by metcoll, December 05, 2018, 08:10:35 PM

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BSB67

Quote from: metcoll on December 09, 2018, 07:07:24 AM
Anyways what I was trying to get at since I have never dynoed this motor on an engine dyno,do you guys think this motor has 500 plus hp and tq..no tracks near by

Based on 360 dynojet HP, no.

500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes
4150 lbs with driver, 3.23 gear, stock converter
11.68 @ 120.2 mph

BSB67

Quote from: flyinlow on December 08, 2018, 02:51:16 PM

If I input the weight of the .race car and it's Hp. The formula will give me the maximum mph trap speed I should see assuming I have an efficient power train ,tire and I drive it well.

If I I input the weight of the race car and it's trap speed. the formula will give me the minimum Hp. The engine makes.

You could interpret it that way considering that one is gross hp and the other is net hp.  However, based on my observations, I would say, generally speaking, statement number 2 gives something close to actual hp.  But you do need to make a reasonable adjustment for PS, alt, fan, full exhaust..., and that is likely the actual flywheel HP.

And statement number 1 is also generally true. (Remember, it's derived from empirical data), if you have good dyno data.  This is where I'm generally a skeptic.  I believe happy dynos are common.  That said, and in defense of engine dyno operator's,  they don't know what an engine/car owner does between the time that the engine leaves the dyno room to going down the track in a car.

Said differently, if you have a realistic engine dyno hp data, you don't screw anything up when you install the engine and make the car operational, statement 1 and 2 will generally show similar HP numbers.

And it is important to correct everything to std conditions, the best you can.

500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes
4150 lbs with driver, 3.23 gear, stock converter
11.68 @ 120.2 mph

c00nhunterjoe

Quote from: INTMD8 on December 09, 2018, 01:19:04 AM
Lmao, I've given several examples. If your search returned nothing relevant I can't imagine your inputs. Do you really think I will not be able to back this up? What you are requesting is not hard to find, pretty much common knowledge.



You have given several opinions and statements about random cars and rough mph differences with no facts about the said cars you refer to in any statement. I provided the manufacturer's own data and website on the 2 different transmissions you refered to regarding a 1-2 mph difference in identical cars with the exception of the transmissions. Their efficiency data confirms the mph difference between the two cars you reference yet you dismiss the manufacture as irrelevant and still ramble on about it.

c00nhunterjoe

Quote from: BSB67 on December 09, 2018, 08:59:51 AM
Quote from: flyinlow on December 08, 2018, 02:51:16 PM

If I input the weight of the .race car and it's Hp. The formula will give me the maximum mph trap speed I should see assuming I have an efficient power train ,tire and I drive it well.

If I I input the weight of the race car and it's trap speed. the formula will give me the minimum Hp. The engine makes.

You could interpret it that way considering that one is gross hp and the other is net hp.  However, based on my observations, I would say, generally speaking, statement number 2 gives something close to actual hp.  But you do need to make a reasonable adjustment for PS, alt, fan, full exhaust..., and that is likely the actual flywheel HP.

And statement number 1 is also generally true. (Remember, it's derived from empirical data), if you have good dyno data.  This is where I'm generally a skeptic.  I believe happy dynos are common.  That said, and in defense of engine dyno operator's,  they don't know what an engine/car owner does between the time that the engine leaves the dyno room to going down the track in a car.

Said differently, if you have a realistic engine dyno hp data, you don't screw anything up when you install the engine and make the car operational, statement 1 and 2 will generally show similar HP numbers.

And it is important to correct everything to std conditions, the best you can.

Agree totally with the above.
As to the hp use of accessories,  the saginaw ps pump uses roughly 10-15 hp depending on the pressure output you have yours set at. A direct drive fan can eat 30+ hp at higher rpm, clutch fans in the 5-10. Alternators vary based on size and load, exhaust varies as well. Full through the tailpipes with freeflowing mufflers can still eat 15+ compared to open header and 18" collectors. Depends on case by case.

INTMD8

Quote from: c00nhunterjoe on December 08, 2018, 11:16:28 PM
From the manufacture of the transmission's website. 3% reduction in power loss over their previous 6 speed.

3% reduction over the previous 6 speed not 3% of total engine output.  So if the old trans consumed 40hp the new one is 38.8.
69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 595rwhp 475rwtq

INTMD8

Same car different trans. Certainly the manual doesn't consume more power than the auto.

And yet, traps 3.7mph faster with the 10 speed. 

If you still want to believe it doesn't matter, believe whatever you want.


https://www.motortrend.com/news/why-the-2018-ford-mustang-gt-automatic-is-so-much-quicker-than-the-manual/
69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 595rwhp 475rwtq

c00nhunterjoe

Quote from: INTMD8 on December 09, 2018, 12:38:20 PM
Same car different trans. Certainly the manual doesn't consume more power than the auto.

And yet, traps 3.7mph faster with the 10 speed.  

If you still want to believe it doesn't matter, believe whatever you want.


https://www.motortrend.com/news/why-the-2018-ford-mustang-gt-automatic-is-so-much-quicker-than-the-manual/

Different final drive as well. It is about as close a comparison you can get, i will give you that. I have still seen identical cars run completely different times at the track side by side as far as mph goes. And even that article says in black and white that the transmission's extra gears are not the sole source of difference. The rear gears allow the mechanical advantage to change between the 2 cars. So again, comes down to the whole package, not justadding more gears. Also, why is a car trapping almost 120mph still in the 12s?

INTMD8

Quote from: c00nhunterjoe on December 08, 2018, 09:05:36 AM
The bottom line is horsepower dictates the mph, not the transmission or rear gear ratio.

Quote from: c00nhunterjoe on December 09, 2018, 01:22:16 PM
The rear gears allow the mechanical advantage to change between the 2 cars. So again, comes down to the whole package, not just adding more gears.


:lol: :lol: :lol: :lol: :lol: :lol:   I'm sorry, what's the bottom line again?    Yes I'm aware gearing influences trap speed.  (that would be trans and final drive) Thanks for playing.
69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 595rwhp 475rwtq

c00nhunterjoe

The total package affects elapsed time. Common knowledge. Thanks for continuing to be an ass. Also explains why an 11 second car is only running 12s. I would bet there was launch control and traction control used on both cars thus pulling power on every shift of the stick car.. Pretty sad that a low 11 second car can only his mid to high 12s with almost 500 hp on tap. Thought that new 10 speed trans would help more but i guess not. Plenty of members on this site trapping the same mph with shitty 3 speeds and lower ets. You are clearly a troll, thus why noone else is even responding to you.

c00nhunterjoe

Quote from: metcoll on December 09, 2018, 07:07:24 AM
Anyways what I was trying to get at since I have never dynoed this motor on an engine dyno,do you guys think this motor has 500 plus hp and tq..no tracks near by

If you want bragging rights you could cheat the dyno. I would bet we could get 400 to the wheels for paper purposes. Drop the belts off the ps and alt. Remove the fan blade from the water pump. Swap the engine oil for some 0w20, dump the diff fluid and only run 1 qt for the dyno session, get the drivetrain good and hot before the dyno pull.

INTMD8

Instead of wanting to have a discussion I'm told I'm an asshole that doesn't know what he's talking about.  As for my attitude, don't be a prick out of the gates and I'll respond in kind.

The entire argument was that gearing affects trap speed to which you repeatedly disputed, then turn around and say "well, the gearing is different which allows mechanical advantage to change between the 2 cars"

Well no shit Chet!  Thanks for repeating what I've said all along as if this is some kind of news to me. 

Stock Mustang on a stock radial, should not be hard to figure out that it could ET better on a tire. Both cars are identical except for the trans/gearing. I'm not Ford's brand ambassador, simply using it as yet another example to prove you wrong.

So again to summarize, you argue gearing doesn't matter then when viewing proof of .5 second et and 3.7mph you turn around and say "well they are geared differently" and "I thought it would make a bigger difference".

Sorry but you are completely full of it.

69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 595rwhp 475rwtq

c00nhunterjoe

Quote from: INTMD8 on December 10, 2018, 09:37:48 AM
Instead of wanting to have a discussion I'm told I'm an asshole that doesn't know what he's talking about.  As for my attitude, don't be a prick out of the gates and I'll respond in kind.

The entire argument was that gearing affects trap speed to which you repeatedly disputed, then turn around and say "well, the gearing is different which allows mechanical advantage to change between the 2 cars"

Well no shit Chet!  Thanks for repeating what I've said all along as if this is some kind of news to me. 

Stock Mustang on a stock radial, should not be hard to figure out that it could ET better on a tire. Both cars are identical except for the trans/gearing. I'm not Ford's brand ambassador, simply using it as yet another example to prove you wrong.

So again to summarize, you argue gearing doesn't matter then when viewing proof of .5 second et and 3.7mph you turn around and say "well they are geared differently" and "I thought it would make a bigger difference".

Sorry but you are completely full of it.



You like to manipulate statements to fit your agenda. Never seen a stick car out et an auto in any way shape or form on stock radials tires. No kidding the auto et's considerably better. The traction control will be cutting power and fuel on every shift in the stick car when the tires break loose. . What happens when you cut power? Oh, thats right, you lose mph. But thats irrelevant because you said so.

c00nhunterjoe

Another perfect example when comparing stick cars. This is a friend's shelby gt500 stick car. Nowhere near stock. Pulley, cams, program, headers exhaust... you name it, its on it.... yet look at the run when the computer is allowed to control traction and stability... whats that you say? Its slower then stock??? How could that be? A 12.40 out of a shelby? At 125mph no less.. So in your arguement, yup, installing the modern auto would drop almost 3 seconds off the et and add several mph, making your arguement technically true, yet still laughable. You would make a good politician.

https://youtu.be/AWjqNlJPZPs

INTMD8

Quote from: c00nhunterjoe on December 10, 2018, 11:57:00 AM
You would make a good politician.

Amusing as you're the guy who did a complete 180 here.  Also love how you felt like you found the holy grail with trans efficiency difference before realizing you had no idea what you were talking about.

As for the stick mustang spinning and cutting power you're straight up making shit up.  You think the auto doesn't have torque management or have the ability to spin on a shift and get reeled back in with as you finally understand -even more mechanical advantage-?  Yeah the stick car is putting less torque to the tires, has the same exact tires and yet it's the one with the traction problem.  Graph of acceleration proves that is not the case.

Enough proof has been posted for you to essentially be quoting my remarks in your defense and you still don't realize you're backpeddling?

This was too easy but I'm growing bored of replying to your moving target of absolute nonsense so I'm out.     :cheers:







69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 595rwhp 475rwtq

c00nhunterjoe

I made up the video with the shelby? Your best arguement to date i must say. The holy grail was found in the last 3 words of your post.

1974dodgecharger

Cant you just get it on the dyno instead of guessing  :icon_smile_big: I know the dyno scares so many people because they expect XXX amount of power and get way less.  So they get mad.....I been on the dyno many times and tune my own car and never gotten mad  :flame: lol....take it as a learning lesson and do better next time and stop guessing what is RWHP vs engine dyno blah blabh blah  :icon_smile_big: