? About Horse Power
Melting Slicks
Joined: Dec 2005
Posts: 2,441
Likes: 0
Accessory loss - unless your using lots of DC it should be minimal. Power steering is minimal down the drag strip or on the dyno. The water pump would be a drain, but I can't imagine more than a few HP, I would think using a lawn mower engine to run it would be overkill. Friction from the belts, now were splitting hairs.
How much do you guys think the accessories rob assuming minimal load on them? Again I would think a 5hp lawn mower engine would be enough to power everything.
How much do you guys think the accessories rob assuming minimal load on them? Again I would think a 5hp lawn mower engine would be enough to power everything.
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Originally Posted by 71CanAm
This percentage stuff has me wondering. I would say the HP loss through an Auto is static. I mean if I have a 500 HP motor and it loses 100 HP at the tranny then if I have a 1000 HP motor wouldn't the tranny still only eat 100 HP? Why would it now be a 200 HP slippage?
The tranny doesn't change. It's still has the same slippage...
The tranny doesn't change. It's still has the same slippage...
f you put a 1000HP motor in the same car then this motor will spin the drum from 3000 to 6000RPM in say 6 seconds. More stress is put on the tranny and all rotating parts, X + ? therefore more heat is going to be generated Y + ? creating a greater loss in HP but essentially the same percentage HP is lost with the 1000HP as the 500HP motor.
But like I said, I don't think the percentage is perfectly linear either as you might lose a smaller percentage as the HP goes up.
I am not a mechanical engineer, these are just my own ideas, but it would be interesting to hear from a mechanical engineer if any of this makes any sense
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Originally Posted by shafrs3
Accessory loss - unless your using lots of DC it should be minimal. Power steering is minimal down the drag strip or on the dyno. The water pump would be a drain, but I can't imagine more than a few HP, I would think using a lawn mower engine to run it would be overkill. Friction from the belts, now were splitting hairs.
How much do you guys think the accessories rob assuming minimal load on them? Again I would think a 5hp lawn mower engine would be enough to power everything.
How much do you guys think the accessories rob assuming minimal load on them? Again I would think a 5hp lawn mower engine would be enough to power everything.
Electric fuel pump and water pump will get you another 5 - 7 HP. Removing mufflers and running straight pipes with large tube headers can give you well over 30 HP...
On a 450 HP engine.. parasitic accessory loss can be EASILY 45++ RWHP!! That's 10%!! The exhaust is the biggest accessory loss!! If you are running stock exhaust manifolds and exhaust, you will be dropping OVER 40 HP on a 450+ HP engine!! I've spent plenty of time at dyno shops and I've seen a lot of before/after pulls and accessories (especially exhaust and mechanical fans) will cost you A LOT of power! That is a fact!!
Last edited by GrandSportC3; Nov 24, 2006 at 10:16 PM.
Advanced
Joined: Sep 2005
Posts: 93
Likes: 0
From: Everett WA
Originally Posted by MotorHead
Again we get back to heat and acceleration. If it takes a 500HP say 10 seconds to go from 3000RPM to 6000RPM on a chassis dyno the forces on the on the automatic and rotating parts are going to be X and Y amount of heat is generated.
f you put a 1000HP motor in the same car then this motor will spin the drum from 3000 to 6000RPM in say 6 seconds. More stress is put on the tranny and all rotating parts, X + ? therefore more heat is going to be generated Y + ? creating a greater loss in HP but essentially the same percentage HP is lost with the 1000HP as the 500HP motor.
But like I said, I don't think the percentage is perfectly linear either as you might lose a smaller percentage as the HP goes up.
I am not a mechanical engineer, these are just my own ideas, but it would be interesting to hear from a mechanical engineer if any of this makes any sense
f you put a 1000HP motor in the same car then this motor will spin the drum from 3000 to 6000RPM in say 6 seconds. More stress is put on the tranny and all rotating parts, X + ? therefore more heat is going to be generated Y + ? creating a greater loss in HP but essentially the same percentage HP is lost with the 1000HP as the 500HP motor.
But like I said, I don't think the percentage is perfectly linear either as you might lose a smaller percentage as the HP goes up.
I am not a mechanical engineer, these are just my own ideas, but it would be interesting to hear from a mechanical engineer if any of this makes any sense
Bearing and gear loses are also a function of the pressure applied to them more HP puts more force on the gears. I'm pretty sure that its linear also, but I would have to look it up. Its been a while since I've done gear computations. Bearing losses are a function of the pressure on the bearing, speed of rotation, and the acceleration
Race Director
Joined: Nov 1999
Posts: 10,643
Likes: 8
From: Foxfield CO 1970 Convertible
Originally Posted by shafrs3
How much do you guys think the accessories rob assuming minimal load on them? Again I would think a 5hp lawn mower engine would be enough to power everything.
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Originally Posted by Z-man
From what I've read, the water pump alone is about 12 - 15 hp. All together, you're probably losing 20hp. More if you have one of those fancy A/Cs hooked up!
Team Owner
Joined: Apr 2002
Posts: 62,198
Likes: 1
From: All humans are vermin in the eyes of Guru VA
Cruise-In IV Veteran
Cruise-In V Veteran
Oliver,
You should look into a burns stainless merge collector. They design them with a venturi to increase power. Their not cheap but if your looking for more power its another place to look.
You should look into a burns stainless merge collector. They design them with a venturi to increase power. Their not cheap but if your looking for more power its another place to look.
Melting Slicks
Joined: Dec 2005
Posts: 2,441
Likes: 0
Originally Posted by GrandSportC3
Really? I picked up 12 RWHP just be eliminating the mechanical fan..
Electric fuel pump and water pump will get you another 5 - 7 HP. Removing mufflers and running straight pipes with large tube headers can give you well over 30 HP...
On a 450 HP engine.. parasitic accessory loss can be EASILY 45++ RWHP!! That's 10%!! The exhaust is the biggest accessory loss!! If you are running stock exhaust manifolds and exhaust, you will be dropping OVER 40 HP on a 450+ HP engine!! I've spent plenty of time at dyno shops and I've seen a lot of before/after pulls and accessories (especially exhaust and mechanical fans) will cost you A LOT of power! That is a fact!!
Electric fuel pump and water pump will get you another 5 - 7 HP. Removing mufflers and running straight pipes with large tube headers can give you well over 30 HP...
On a 450 HP engine.. parasitic accessory loss can be EASILY 45++ RWHP!! That's 10%!! The exhaust is the biggest accessory loss!! If you are running stock exhaust manifolds and exhaust, you will be dropping OVER 40 HP on a 450+ HP engine!! I've spent plenty of time at dyno shops and I've seen a lot of before/after pulls and accessories (especially exhaust and mechanical fans) will cost you A LOT of power! That is a fact!!
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Drifting
Joined: May 2006
Posts: 1,544
Likes: 0
From: Youngstown Ohio
Open 4" exhaust, M-21, Frankland Rear end, all electrical except alt. and 1 fuel pump, dry sump pump, we are losing 9-10% as measured on an engine dyno vs. chassis dyno.
Last edited by 73-84 IMSA Widebody; Nov 25, 2006 at 01:02 PM.
