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Re: Rear Wheel HP vs Flywheel HP
[Re: MaxHeadroom]
#1407102
03/23/13 01:59 PM
03/23/13 01:59 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Turbo engines are a little hard to predict the losses on but if its that bad its most likely a conv issue... no one would loose 50%(or there abouts)... and is the dyno number real or just some real happy dyno but it is likely the conv (blowing right through it) 
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Re: Rear Wheel HP vs Flywheel HP
[Re: AndyF]
#1407106
03/23/13 07:03 PM
03/23/13 07:03 PM
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Joined: Dec 2012
Posts: 145
North East
MaxHeadroom
OP
member
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OP
member
Joined: Dec 2012
Posts: 145
North East
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Quote:
Are you asking a general question or about a particular car? There can be any number of things wrong with a specific car.
There are fairly good rules for figuring out drivetrain loss.
Wanted to know in general, but was looking at a specific car and trying to figure out why its performance does not match up with Dyno reading. Its a Procharged stroked 440 and dyno showed 1386Hp, but performance wise it is an 11 sec car, when it should be 9 for sure. Either there is something wrong with the setup or the dyno readings are off, can't see losing that much power.
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Re: Rear Wheel HP vs Flywheel HP
[Re: MaxHeadroom]
#1407107
03/23/13 07:19 PM
03/23/13 07:19 PM
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Joined: Jan 2003
Posts: 3,943
Melbourne.....Oz-land
Moparmal
master
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master
Joined: Jan 2003
Posts: 3,943
Melbourne.....Oz-land
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I know Ford allocate around 17% on their factory automatic drive trains. My experience with 904/727 , 8.75 and a 3500 stall shows between 20 and 22%. Tire compound and tire diameter can also make a significant difference. New LX Auto cars reportedly lose around 18-20% due to tire diameter and the Nag1 slushbox Cant help you with any turbo data..... 
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Re: Rear Wheel HP vs Flywheel HP
[Re: Moparmal]
#1407108
03/23/13 08:17 PM
03/23/13 08:17 PM
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Joined: Jan 2005
Posts: 2,540
Milwaukee WI
TRENDZ
master
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master
Joined: Jan 2005
Posts: 2,540
Milwaukee WI
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You only lose what your driveline absorbs. You cannot assign a pecentage.
If I have a 500hp engine in my car, than take it out and replace it with a 1000hp engine, the driveline is not going to take more to drive.
Some people say you lose 20% to your driveline. How would that workout with my example?
"use it 'till it breaks, replace as needed"
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Re: Rear Wheel HP vs Flywheel HP
[Re: TRENDZ]
#1407109
03/23/13 09:00 PM
03/23/13 09:00 PM
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Joined: Apr 2007
Posts: 951
Temperance, MI
prochargedhemi
super stock
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super stock
Joined: Apr 2007
Posts: 951
Temperance, MI
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Quote:
You only lose what your driveline absorbs. You cannot assign a pecentage.
If I have a 500hp engine in my car, than take it out and replace it with a 1000hp engine, the driveline is not going to take more to drive.
Some people say you lose 20% to your driveline. How would that workout with my example?
convertor slippage, the only real way to know what the actual lose is would be to have a driveshaft pickup and see what the percentage is. even then there are still a bunch of variables. there is a reason people don't race dynos. they are tuning tools and to be used as such
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Re: Rear Wheel HP vs Flywheel HP
[Re: prochargedhemi]
#1407110
03/23/13 09:24 PM
03/23/13 09:24 PM
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Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
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I have read about a 500 hp eng in a basic street car that had about 420 at the wheels. Thats just a general idea as of course it depends on what driveline setup you run. But I would think on rear wheel drive cars in the 400 to 600 hp area anywhere from from about 60 to 100 hp driveline loss is about normal ? One calculator rated my car at about 600 flywheel and 525 at the wheels. Ron
Last edited by 383man; 03/23/13 09:27 PM.
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Re: Rear Wheel HP vs Flywheel HP
[Re: 383man]
#1407111
03/23/13 09:34 PM
03/23/13 09:34 PM
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Joined: Aug 2011
Posts: 2,871
Pattison Texas
CSK
master
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master
Joined: Aug 2011
Posts: 2,871
Pattison Texas
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the harder & faster you try to turn something, more friction is produced.. thats why it is a % loss
1968 Charger COLD A/C Hilborn EFI
512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim
2020 T/A 392 Stock 11.79 @ 114.5
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Re: Rear Wheel HP vs Flywheel HP
[Re: TRENDZ]
#1407112
03/23/13 09:35 PM
03/23/13 09:35 PM
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Joined: Jan 2003
Posts: 3,943
Melbourne.....Oz-land
Moparmal
master
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master
Joined: Jan 2003
Posts: 3,943
Melbourne.....Oz-land
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Quote:
You only lose what your driveline absorbs. You cannot assign a pecentage.
If I have a 500hp engine in my car, than take it out and replace it with a 1000hp engine, the driveline is not going to take more to drive.
Some people say you lose 20% to your driveline. How would that workout with my example?
I agree - and the faster you rotate the driveline, the greater in frictional and inertial losses...so the % doesn't remain constant.
Unfortunately you took my examples as being "generic",...when my intention was to simpy provide some examples related to some more common drivetrain scenarios 
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Re: Rear Wheel HP vs Flywheel HP
[Re: 383man]
#1407113
03/23/13 09:38 PM
03/23/13 09:38 PM
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Joined: Jan 2003
Posts: 3,943
Melbourne.....Oz-land
Moparmal
master
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master
Joined: Jan 2003
Posts: 3,943
Melbourne.....Oz-land
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Quote:
I have read about a 500 hp eng in a basic street car that had about 420 at the wheels. Thats just a general idea as of course it depends on what driveline setup you run. But I would think on rear wheel drive cars in the 400 to 600 hp area anywhere from from about 60 to 100 hp driveline loss is about normal ? One calculator rated my car at about 600 flywheel and 525 at the wheels. Ron
Ron..I know of one engine builder that swears you can almost set your clock at 110 HP for a small block driving a 727, a 4000 stall and a 9" on a 27" tire.
He also believes around 80Hp for the same scenario with a 904.
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Re: Rear Wheel HP vs Flywheel HP
[Re: Moparmal]
#1407114
03/23/13 09:52 PM
03/23/13 09:52 PM
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Joined: Jan 2003
Posts: 1,481
Outside
thedriver
pro stock
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pro stock
Joined: Jan 2003
Posts: 1,481
Outside
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Ron..I know of one engine builder that swears you can almost set your clock at 110 HP for a small block driving a 727, a 4000 stall and a 9" on a 27" tire. He also believes around 80Hp for the same scenario with a 904.
 my 340/727/10" loose converter was right in that range. One of the reasons I'm converting to stick. All this hp costs money, disheartening when the driveline takes it away.
1973 challenger
Dana. 4 speed. Low deck.
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Re: Rear Wheel HP vs Flywheel HP
[Re: MaxHeadroom]
#1407115
03/23/13 11:51 PM
03/23/13 11:51 PM
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Joined: Oct 2007
Posts: 4,210
New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,210
New York
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How to tell when your 727 is consuming 500 hp:
the car is a giant fireball.
Boffin Emeritus
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Re: Rear Wheel HP vs Flywheel HP
[Re: MaxHeadroom]
#1407120
03/30/13 07:42 PM
03/30/13 07:42 PM
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Joined: Aug 2005
Posts: 6,017
Salem
Grizzly
Moparts Proctologist
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Moparts Proctologist
Joined: Aug 2005
Posts: 6,017
Salem
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18 to 22% Manual 24 to 28% Auto Lowly, but very consistent example: I've had 318's with 4 speeds, 904's and 727's and there's no doubt in my mind: the 727 is a power-robbing turd. They have purpose: I can't break one. 
Mo' Farts
Moderated by "tbagger".
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Ron
