LS1 HP In reality?
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Joined: Sep 2003
Posts: 503
From: Mtn. Home AFB, ID (really from Texas)
The loads will not be constant. As power increases bearing load increases causing drivetrain loses. I agree it wouldn't be a linear percentage rate, but more of an exponential rate where drivetrain loses decrease at an exponential rate as hp increases.
Example: say you have 300 hp stock at the rear wheels and you pull the engine and put it on a chassis dyno and it has 352 hp at the flywheel. That's a 15% loss or 52 hp. Now lets say you do a head/cam swap along with all the boltons. You dyno it at 475 hp at the rear wheels then you pull the engin again and run the engine on a dyno and have 540 hp at the flywheel. That's a 12% loss or 65 hp. Now lets say you add twin turbo's. You dyno it at 650 hp at the wheels and then dyno the engine and get 722 hp. That is a 10% hp loss or 72hp.
That is all hypothetical. I have no hard facts to back it up it is merely my theory of how it works. As you can see the percentages decrease as horsepower increases, but powerloses increase as horsepower increases.
Example: say you have 300 hp stock at the rear wheels and you pull the engine and put it on a chassis dyno and it has 352 hp at the flywheel. That's a 15% loss or 52 hp. Now lets say you do a head/cam swap along with all the boltons. You dyno it at 475 hp at the rear wheels then you pull the engin again and run the engine on a dyno and have 540 hp at the flywheel. That's a 12% loss or 65 hp. Now lets say you add twin turbo's. You dyno it at 650 hp at the wheels and then dyno the engine and get 722 hp. That is a 10% hp loss or 72hp.
That is all hypothetical. I have no hard facts to back it up it is merely my theory of how it works. As you can see the percentages decrease as horsepower increases, but powerloses increase as horsepower increases.
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Joined: Jul 1998
Posts: 6,247
From: Charlotte,MI USA
Originally posted by mullettour
The loads will not be constant. As power increases bearing load increases causing drivetrain loses. I agree it wouldn't be a linear percentage rate, but more of an exponential rate where drivetrain loses decrease at an exponential rate as hp increases.
The loads will not be constant. As power increases bearing load increases causing drivetrain loses. I agree it wouldn't be a linear percentage rate, but more of an exponential rate where drivetrain loses decrease at an exponential rate as hp increases.
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Joined: Aug 2003
Posts: 192
All that sounds really logical. However
with the hundreds of thousands of auto engineers
out there I don't think I'd be hearing this for the
first time on a fbod forum rebuting the excepted norm.
Advertising isn't a factor, whens the last time you
saw rwhp in an ad.
with the hundreds of thousands of auto engineers
out there I don't think I'd be hearing this for the
first time on a fbod forum rebuting the excepted norm.
Advertising isn't a factor, whens the last time you
saw rwhp in an ad.
Registered User
Joined: Jan 2003
Posts: 1,362
Originally posted by mullettour
The loads will not be constant. As power increases bearing load increases causing drivetrain loses. I agree it wouldn't be a linear percentage rate, but more of an exponential rate where drivetrain loses decrease at an exponential rate as hp increases.
Example: say you have 300 hp stock at the rear wheels and you pull the engine and put it on a chassis dyno and it has 352 hp at the flywheel. That's a 15% loss or 52 hp. Now lets say you do a head/cam swap along with all the boltons. You dyno it at 475 hp at the rear wheels then you pull the engin again and run the engine on a dyno and have 540 hp at the flywheel. That's a 12% loss or 65 hp. Now lets say you add twin turbo's. You dyno it at 650 hp at the wheels and then dyno the engine and get 722 hp. That is a 10% hp loss or 72hp.
That is all hypothetical. I have no hard facts to back it up it is merely my theory of how it works. As you can see the percentages decrease as horsepower increases, but powerloses increase as horsepower increases.
The loads will not be constant. As power increases bearing load increases causing drivetrain loses. I agree it wouldn't be a linear percentage rate, but more of an exponential rate where drivetrain loses decrease at an exponential rate as hp increases.
Example: say you have 300 hp stock at the rear wheels and you pull the engine and put it on a chassis dyno and it has 352 hp at the flywheel. That's a 15% loss or 52 hp. Now lets say you do a head/cam swap along with all the boltons. You dyno it at 475 hp at the rear wheels then you pull the engin again and run the engine on a dyno and have 540 hp at the flywheel. That's a 12% loss or 65 hp. Now lets say you add twin turbo's. You dyno it at 650 hp at the wheels and then dyno the engine and get 722 hp. That is a 10% hp loss or 72hp.
That is all hypothetical. I have no hard facts to back it up it is merely my theory of how it works. As you can see the percentages decrease as horsepower increases, but powerloses increase as horsepower increases.
However I still say rear wheel horsepower is a big factor for advertising. I don't think it would take much to have chevrolet dyno 10 seperate cars and average them out and advertise the rear wheel horsepower.
Registered User
Joined: Aug 2003
Posts: 192
Why would they advertise a number that is lower.
Most people wouldn't understand that and assume
its not as powerful. The industry uses a given standard
and it isn't RW. Why would a company do anything different
especially to show lower numbers, what would they gain.
Lets say they say a C5 is 300(rwhp) the average Joe
look at that and says its just as strong as a STI.
Most people wouldn't understand that and assume
its not as powerful. The industry uses a given standard
and it isn't RW. Why would a company do anything different
especially to show lower numbers, what would they gain.
Lets say they say a C5 is 300(rwhp) the average Joe
look at that and says its just as strong as a STI.
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Joined: Jan 2003
Posts: 1,362
Jeez, that is exactly what I am saying! Someone stated "Well why don't dealers put a x amount for drivetrain loss" and my response was because they would have to worry about advertising it.... Please read the post...If this wasn't directed towards me, sorry.
Last edited by Pasky; May 1, 2004 at 01:41 PM.
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Joined: Aug 2003
Posts: 192
Did anyone see the article in car and driver about
dynos in a recent issue. They got like a 50 hp gap with
the same car. Had to do with getting air blown at it.
It was a BMW...M5 I think.
Basicly they said a dyno reading is only representative
of a given car's performance on a given day with given conditions.
Doesn't speak much for the factualness of a dynos readings.
Motor dynos seem to be alot more accurate than chasis dynos.
Speaking in terms of validity over time.
Thats another reason the automakers use them but they
manipulate them for marketing of the vehicle or for the sake
of another.
dynos in a recent issue. They got like a 50 hp gap with
the same car. Had to do with getting air blown at it.
It was a BMW...M5 I think.
Basicly they said a dyno reading is only representative
of a given car's performance on a given day with given conditions.
Doesn't speak much for the factualness of a dynos readings.
Motor dynos seem to be alot more accurate than chasis dynos.
Speaking in terms of validity over time.
Thats another reason the automakers use them but they
manipulate them for marketing of the vehicle or for the sake
of another.
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Joined: Jul 2003
Posts: 220
From: BAY-AREA CALI
Originally posted by 94ZRiCeKiLr
these are numbers meant to make the SS/WS6 look like there is actually more of a difference from the "base" V8s then there is....
the extra hp in the top of the line models is credited to a less restrictive exhaust and the "functional" ram air which is actually useless on the SS and marginally functional on the WS6.
if you take a bone stock SS and a bone stock Z28 and stick them on the same dyno, they will produce the same numbers or SLIGHTLY different ones...any difference will from the SS exhaust since the ram air (if it worked) wouldnt be of any use on a stationary dyno anyway...
in short, an LS1 is an LS1 is an LS1....any actual power difference in the different models will be completely negated once the car is modified with a lid and catback....a Z28 with a lid and loudmouth is EXACTLY the same as an SS with a lid and loudmouth powerwise...
these are numbers meant to make the SS/WS6 look like there is actually more of a difference from the "base" V8s then there is....
the extra hp in the top of the line models is credited to a less restrictive exhaust and the "functional" ram air which is actually useless on the SS and marginally functional on the WS6.
if you take a bone stock SS and a bone stock Z28 and stick them on the same dyno, they will produce the same numbers or SLIGHTLY different ones...any difference will from the SS exhaust since the ram air (if it worked) wouldnt be of any use on a stationary dyno anyway...
in short, an LS1 is an LS1 is an LS1....any actual power difference in the different models will be completely negated once the car is modified with a lid and catback....a Z28 with a lid and loudmouth is EXACTLY the same as an SS with a lid and loudmouth powerwise...
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Joined: Dec 2002
Posts: 821
Originally posted by LetMeBurnU
Alright for example: For the stock 2001 Z28/Formula is rated 310 HP, say u add a lid and a catback then how much hp will the Z and the formula's be...?
Alright for example: For the stock 2001 Z28/Formula is rated 310 HP, say u add a lid and a catback then how much hp will the Z and the formula's be...?
--i would say that a stock 2001 Z28 with an M6 would put out about 300-305 rear wheel hp (approx 345 flywheel hp with a 12% drivetrain loss). with a lid and catback, i've seen otherwise stock cars dyno 320-330 rwhp (approx 370 flywheel hp) (my friends 02 dynoed 331 with a lid and loudmouth).
--most stock A4s put out around 288-292 rwhp (approx 345 flywheel with a 15% drivetrain loss). with the same lid and catback, an A4 should dyno around 310-315 rwhp. (approx 370 flywheel hp with a 15% loss).
overall, it seems that a lid and a good catback are worth 20-25 RWHP.
the numbers with the lid and catback would more than likely be IDENTICAL to an SS, T/A or WS6 with a lid and catback...once those small mods are done, there is NO power difference between any of the LS1 equipped models....
assuming the same transmission, all lid/catback equipped f-bodies are essentially equal...
Last edited by 94ZRiCeKiLr; May 1, 2004 at 05:37 PM.
Registered User
Joined: Apr 2001
Posts: 674
From: Sac, CA
Originally posted by Pasky
Jeez, that is exactly what I am saying! Someone stated "Well why don't dealers put a x amount for drivetrain loss" and my response was because they would have to worry about advertising it.... Please read the post...If this wasn't directed towards me, sorry.
Jeez, that is exactly what I am saying! Someone stated "Well why don't dealers put a x amount for drivetrain loss" and my response was because they would have to worry about advertising it.... Please read the post...If this wasn't directed towards me, sorry.
That's why drive train loss is a percentage and not constant. And it's not even a constant percentage ... as the horsepower increases the percentage of drivetrain loss will actually go up ...
This is the same reason you can add 10 horsepower to a 13.5 second car and you will knock an easy tenth plus off your time ... but add 10 horsepower to an 11.0 second car and you might pick up a half a tenth ...
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Joined: Jan 2003
Posts: 1,362
Excellent point and I will have to agree with this and take back my constant saying as after comparing vehicles and results it seems this is so, however I still disagree with people who still factor in the xx% that gm rated to thier modded vehicles and still think thier getting gobs of horsepower because they incorrectly calculated thier drivetrain loss by multiplying a bigger percentage.
Registered User
Joined: May 2000
Posts: 528
From: Southwest VA
Originally posted by LetMeBurnU
Alright for example: For the stock 2001 Z28/Formula is rated 310 HP, say u add a lid and a catback then how much hp will the Z and the formula's be...?
Alright for example: For the stock 2001 Z28/Formula is rated 310 HP, say u add a lid and a catback then how much hp will the Z and the formula's be...?
Registered User
Joined: Apr 2001
Posts: 674
From: Sac, CA
Originally posted by Pasky
Excellent point and I will have to agree with this and take back my constant saying as after comparing vehicles and results it seems this is so, however I still disagree with people who still factor in the xx% that gm rated to thier modded vehicles and still think thier getting gobs of horsepower because they incorrectly calculated thier drivetrain loss by multiplying a bigger percentage.
Excellent point and I will have to agree with this and take back my constant saying as after comparing vehicles and results it seems this is so, however I still disagree with people who still factor in the xx% that gm rated to thier modded vehicles and still think thier getting gobs of horsepower because they incorrectly calculated thier drivetrain loss by multiplying a bigger percentage.
1. There is no available imperical data for what that loss is. Until someone does a series of tests on an engine dyno vs full dyno ... everyone is speculating.
The closest I'll take the word of, is if an actual automotive engineer posted and presented some data to back it up ...
2. So once you have the results, which dyno? there are at least 3 different dynos out there that I know of and every one of them will give different results ... A load bearing dyno such as a Mustang, which typically has lower results than a Dynojet, can probably have case made that the drive train loss is higher than on a non-load bearing dyno.
3. Last is dyno calibration. The Dynojet alone has, I believe at least, 3 different calibration modes that the operator can select. I've seen less than competent operators even change the modes between runs.
And I also know of operators that have tweeked their dynos to give higher results in order to get business ... can't blame them. Only about 10% of the people who use a dyno really know what the data means and how to apply it ... the other 90% are looking to be dyno queens ...
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