Welcome to the North American Subaru Impreza Owners Club Tuesday September 23, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC General > Newbies & FAQs

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 07-04-2006, 02:59 AM   #1
JDM_Scobaru
Scooby Specialist
 
Member#: 57809
Join Date: Mar 2004
Chapter/Region: MWSOC
Location: West Virginia University
Question Is turbocharged/supercharged/NA horse the same?

Well this question has bothered me, and it seems simple untill I really start to think about it. So, let's say, that we have an 3 of the same type of car with the same weight (besides minor things for NA,Turbo,supercharger differences), same gearing,same drivetrain, everything is the same. Lets say the car also makes 250 Hp. The car can make 250 Hp in either form, whether it is turbo, superch'd, or NA'd. Would all of the cars run identical times, whether it be quarter mile, 60 fts, etc? Any thoughts would be nice.

Thanks,
Zach
* Registered users of the site do not see these ads.
JDM_Scobaru is offline   Reply With Quote
Old 07-04-2006, 03:07 AM   #2
WR^2X
Scooby Specialist
 
Member#: 37617
Join Date: May 2003
Vehicle:
2007

Default

If you took three cars that were all exactly the same except for how they made their power (and their power curves were all the same), then they'd all run the same.
WR^2X is offline   Reply With Quote
Old 07-04-2006, 03:09 AM   #3
kheovnien
Scooby Specialist
 
Member#: 79025
Join Date: Jan 2005
Chapter/Region: SCIC
Location: SoCal
Vehicle:
2004 WRX
WRB

Default

horsepower rating on a car is only the maximum horsepower that the car achieves and tells u very little about the engine's performance. torque, torque curve, and the powerband play a big role as well as the delivery to the differentials and wheels. im sure someone here or somewhere on the interenet there's probably a comparison or an article about it.
kheovnien is offline   Reply With Quote
Old 07-04-2006, 03:26 AM   #4
Griever423
Scooby Newbie
 
Member#: 118749
Join Date: Jun 2006
Chapter/Region: TXIC
Location: Fort Worth, TX
Vehicle:
2013 BRZ
WRB

Default

Quote:
Originally Posted by kheovnien
horsepower rating on a car is only the maximum horsepower that the car achieves and tells u very little about the engine's performance. torque, torque curve, and the powerband play a big role as well as the delivery to the differentials and wheels. im sure someone here or somewhere on the interenet there's probably a comparison or an article about it.
Ceteris paribus dude. I'm quite sure even though he didnt include it, that torque is also understood to be equal.
Griever423 is offline   Reply With Quote
Old 07-04-2006, 03:31 AM   #5
John2.5RS
Scooby Guru
 
Member#: 1140
Join Date: Mar 2000
Chapter/Region: SCIC
Location: On the road
Vehicle:
2013 Ecoboost'd F150
Grey

Default

Well, what about the TQ? What is the redline? what kind of displacement does the motor have? how many cylinders? There are waaaay to many variables. If they all had the exact same powerband(unlikely) and driver they should all be just the same. But we all know that wouldn't be the case. also, the N/A motor(assuming we're talking subi's) would cost more than a turbo set-up making that kind of power. It really boils down to packaging. If you want to make a S/C fit, you can, it's been done several times, do a search and you'll see. Turbo's seem to be the way to go. one of the nice thing about turbos compared to most s/c's(not talking about the merc with the clutch-driven blower) is that You can get fairly good gas mileage due to the fact that you can stay out of boost(and make less power=consume less fuel) unlike S/C setups. And with the turbos, it's using the heat energy in the exhaust gases to create boost, as opposed to the s/c which draws it's power from the crankshaft, (parasitic draw). It's late and I don't make much sense but you may get the idea. If it's a subi, I'd rock the turbo!
John2.5RS is offline   Reply With Quote
Old 07-04-2006, 03:37 AM   #6
cstratton04
Scooby Specialist
 
Member#: 84489
Join Date: Apr 2005
Chapter/Region: NWIC
Location: Pullman, WA
Vehicle:
2005 Toyota Corolla
2005 CBR600rr

Default

Quote:
Originally Posted by Griever423
Ceteris paribus dude. I'm quite sure even though he didnt include it, that torque is also understood to be equal.
The torque won't be equal though. All three options will have different torque ratings, but even if the torques (I am assuming you mean peak torque) were the same the cars would be different. Like kheovnien said, torque curves play a big role on acceleration.

Basically, you can assume that if all three cars had the same peak hp, they would still run different acceleration times. Also, driver skill would play a very large role.
cstratton04 is offline   Reply With Quote
Old 07-04-2006, 05:12 AM   #7
scrabby
Scooby Newbie
 
Member#: 115308
Join Date: May 2006
Chapter/Region: RMIC
Location: Mountains, CO
Vehicle:
'13 Snow Scalpel
WRB

Default

Sorry to hijack, but you guys can probably explain this:

What would happen if you had a car with 1000hp and 1 ft/lb of torque?
Or a car with 1hp and 1000 ft/lb of torque?
All other things being equal.

What gearing would you need?

I'm not terribly good at math/science.
scrabby is offline   Reply With Quote
Old 07-04-2006, 06:48 AM   #8
FD777
Scooby Newbie
 
Member#: 84820
Join Date: Apr 2005
Chapter/Region: BAIC
Location: Santa Clara/Sunnyvale, CA
Vehicle:
2005 WRX Sedan
Crystal Gray

Default

Quote:
Originally Posted by scrabby
Sorry to hijack, but you guys can probably explain this:

What would happen if you had a car with 1000hp and 1 ft/lb of torque?
Or a car with 1hp and 1000 ft/lb of torque?
All other things being equal.

What gearing would you need?

I'm not terribly good at math/science.
I would GUESS:
1000 hp and 1 ft/lb torque - Car wouldn't even be able to pull its own weight. Thus it wouldn't even move. And if your car did somehow manage to gain some momentum, you could go pretty fast... it just might take a while.

1 hp and 1000 ft/lb - Car would move pretty slow, but it could still move. With all that torque, you could probably add a hefty trailor and the car would still go.

My mechanical physics intution sucks though... I haven't used it in 5-6 years
FD777 is offline   Reply With Quote
Old 07-04-2006, 07:15 AM   #9
andrew_j
Scooby Newbie
 
Member#: 102026
Join Date: Dec 2005
Chapter/Region: NESIC
Location: Seacoast NH
Vehicle:
2004 WRX Wagon

Default

The times would vary dependant on torque and HP curves. A great example is the 5-60 time of a Forester XT <Subaru WRX with the 2.0L.
andrew_j is offline   Reply With Quote
Old 07-04-2006, 10:25 AM   #10
G3Red04WRX
Scooby Specialist
 
Member#: 66611
Join Date: Jul 2004
Chapter/Region: MWSOC
Location: Streamwood, IL
Vehicle:
2007 Trailblazer AWD
3LT Sandstone Metallic

Default

Just taking a stab at the original question, but assuming ALL variables other than what is making power (turbo, s/c or NA) I would like to think that in this order they would cross the finish line:

1) N/A
2) S/C
3) Turbo

Now here is my feeble attempt to explain my opinion:

1) Car is ALL motor driven, the power is always there for you. Car is making more torque thru the entire powerband than a forced induction vehicle, hence pushing it easier down the strip.

2) S/C is constantly increasing its power output capabilities to the motor the faster the motor is revolving. It will start off with lower power, but will keep increasing as it approaches redline, simulating a N/A situation.

3) Turbo is dependant on 2 factors: Engine speed and airflow capacity. The turbo will be slow to build up boost in the intake line until the engine is producing similar power output of the N/A vehicle. Also, there is a point where turbos typically operate beyond their capabilities and just start blowing hot air making them less efficient.

Now like i said, this is my opinion when ALLLLL other factors are assumed to be IDENTICAL. In the real world, this assumpition has no practical application because there are literally millions of variables to be taken account for, so essentially, i just spent all this time writing this post when i could have been doing something more useful with my time, like looking at pics of STI's with pink wheels....
G3Red04WRX is offline   Reply With Quote
Old 07-04-2006, 11:15 AM   #11
Master2192
RIP 10/12/83 to 02/10/08
Scooby Specialist
 
Member#: 83254
Join Date: Mar 2005
Chapter/Region: NWIC
Location: Roy, Washington
Vehicle:
98 2.5 RS
04 WRX

Default

Quote:
Originally Posted by scrabby
Sorry to hijack, but you guys can probably explain this:

What would happen if you had a car with 1000hp and 1 ft/lb of torque?
Or a car with 1hp and 1000 ft/lb of torque?
All other things being equal.

What gearing would you need?

I'm not terribly good at math/science.
Well, with that 1 ft/lb of torque. You'd need to spin that poor motor to 5252000 rpms to get 1000hp. So with the right gearing, you could launch at a million rpms and it would do the 1/4 mile pretty damn fast. Of course it would have to be made from unobtainium.

Then, to have 1hp with 1000ft lbs, the engine would need to do 5.252 rpms. You could not divide the torque enough to make a difference.

HP is the amount of work divided by time. Whichever car has the most average horsepower will win. If they make the same torque at every RPM, then they are equal.
Master2192 is offline   Reply With Quote
Old 07-04-2006, 11:59 AM   #12
REX8
*** Banned ***
 
Member#: 24038
Join Date: Sep 2002
Chapter/Region: South East
Location: Godspeed Cale...
Default

Quote:
Originally Posted by John2.5RS
Well, what about the TQ? What is the redline? what kind of displacement does the motor have? how many cylinders? There are waaaay to many variables. If they all had the exact same powerband(unlikely) and driver they should all be just the same. But we all know that wouldn't be the case. also, the N/A motor(assuming we're talking subi's) would cost more than a turbo set-up making that kind of power. It really boils down to packaging. If you want to make a S/C fit, you can, it's been done several times, do a search and you'll see. Turbo's seem to be the way to go. one of the nice thing about turbos compared to most s/c's(not talking about the merc with the clutch-driven blower) is that You can get fairly good gas mileage due to the fact that you can stay out of boost(and make less power=consume less fuel) unlike S/C setups. And with the turbos, it's using the heat energy in the exhaust gases to create boost, as opposed to the s/c which draws it's power from the crankshaft, (parasitic draw). It's late and I don't make much sense but you may get the idea. If it's a subi, I'd rock the turbo!
Torque is what makes HP. If they have the same HP for a given RPM, they have the same torque...
REX8 is offline   Reply With Quote
Old 07-04-2006, 12:01 PM   #13
JimBlake
Scooby Newbie
 
Member#: 82247
Join Date: Mar 2005
Location: NE Ohio
Vehicle:
2005 Saab 9.2x Aero
satin grey

Default

Lots of people were close to the answer, without a good explanation.

If the HP were the same, that says nothing about the shape of the HP curve at all different RPM. Only if the entire HP curve is identical, then they'd have the same 1/4 mile time. (Driver skills notwithstanding...)

If 2 engines have the same peak HP at the same RPM, it still doesn't guarantee the whole curve is the same. One engine could have much better power at 2000 rpm to 5000 rpm while at 6000 rpm the power is the same. That would make a big difference. If you don't know the entire HP curve, the torque # can give you a reasonable clue (but still incomplete).
JimBlake is offline   Reply With Quote
Old 07-04-2006, 12:01 PM   #14
cstratton04
Scooby Specialist
 
Member#: 84489
Join Date: Apr 2005
Chapter/Region: NWIC
Location: Pullman, WA
Vehicle:
2005 Toyota Corolla
2005 CBR600rr

Default

HP = torque*RPM/5252

Assuming everything else is equal, they will be the same but need different gearing.
cstratton04 is offline   Reply With Quote
Old 07-04-2006, 12:03 PM   #15
REX8
*** Banned ***
 
Member#: 24038
Join Date: Sep 2002
Chapter/Region: South East
Location: Godspeed Cale...
Default

Quote:
Originally Posted by JimBlake
Lots of people were close to the answer, without a good explanation.

If the HP were the same, that says nothing about the shape of the HP curve at all different RPM. Only if the entire HP curve is identical, then they'd have the same 1/4 mile time. (Driver skills notwithstanding...)

If 2 engines have the same peak HP at the same RPM, it still doesn't guarantee the whole curve is the same. One engine could have much better power at 2000 rpm to 5000 rpm while at 6000 rpm the power is the same. That would make a big difference. If you don't know the entire HP curve, the torque # can give you a reasonable clue (but still incomplete).
Yes, the entire curves must be the same, thats been said a number of times...
REX8 is offline   Reply With Quote
Old 07-04-2006, 12:49 PM   #16
NattiRex
Scooby Newbie
 
Member#: 96738
Join Date: Sep 2005
Chapter/Region: Tri-State
Location: Nasty Natti
Vehicle:
96 Talon
Blue

Default

IF the torque curves were identical (which is impossibe) yes they would run the same times.

1,000HP and llbfttq = insainly high revs but would drvie fine, totally unrealistic
1,000lbft and 1hp = car would not drvie at all
NattiRex is offline   Reply With Quote
Old 07-04-2006, 01:04 PM   #17
JDM_Scobaru
Scooby Specialist
 
Member#: 57809
Join Date: Mar 2004
Chapter/Region: MWSOC
Location: West Virginia University
Default

Hmm some good insight from you guys.


Thanks,
Zach
JDM_Scobaru is offline   Reply With Quote
Old 07-04-2006, 06:59 PM   #18
NattiRex
Scooby Newbie
 
Member#: 96738
Join Date: Sep 2005
Chapter/Region: Tri-State
Location: Nasty Natti
Vehicle:
96 Talon
Blue

Default

Just to add on, to acheive 1000hp with 1 lbft og torque you have to rev to ~52,000rpm

To net a mere 1 hp out of 1,000lbft of torque you can ONLY rev to roughly 5 RPM, thats 1 revolution every 12ish seconds....
NattiRex is offline   Reply With Quote
Old 07-05-2006, 01:25 AM   #19
Izomorph
Scooby Newbie
 
Member#: 115521
Join Date: May 2006
Location: BC
Vehicle:
2006 Impreza wagon
crystal grey metalic

Default

you can think of horsepower as the amount of kinetic energy the engine can put out based off of the constant, in this case, rpm's. Most measurements are how much the engine can drive the crank. HP is kinda misleading to use as a unit of measurment though, because part of the direct equation to HP is weight.

On the other hand, torque can be thought of as the amount of pressure the engine produces when turning the shaft. Consequently torque is important for moving heavy objects.

But, yes, there are too many factors to say that three equal cars will perform like the other. Just so you know, the basic concept behind turbo is that the turbine is driven through the exaust. This means there has to be more exaust and thus higher rpms to produce a decent amount of turbo boost. A supercharger uses the intake to produce the additional power. This tends to produce a more level gain throughout the rpm range. Then again, there's the issue of the "so many factors" in performance...
Izomorph is offline   Reply With Quote
Old 07-05-2006, 01:54 AM   #20
ThrawlWRX
Scooby Newbie
 
Member#: 55878
Join Date: Feb 2004
Chapter/Region: SCIC
Location: BFIE
Vehicle:
2013 GR LTD & 03 GD
SWP / PSM

Default

I couldn't see an N/A motor, a Turbo motor, and a S/C motor having anything similar as far as TQ curve. They could all have the same HP maybe... if you built them right. But The NA is going to have a linear band... The Turbo will start low and come up high for the topend. And the S/C would not be a strong down low as the NA ... nor have the top end of the Turbo... but it will have lots of mid range power... This is a bad question IMO... sorry. lol
ThrawlWRX is offline   Reply With Quote
Old 07-05-2006, 02:46 AM   #21
cstratton04
Scooby Specialist
 
Member#: 84489
Join Date: Apr 2005
Chapter/Region: NWIC
Location: Pullman, WA
Vehicle:
2005 Toyota Corolla
2005 CBR600rr

Default

Quote:
Originally Posted by Izomorph
he engine can put out based off of the constant, in this case, rpm's. you can think of horsepower as the amount of kinetic energy tMost measurements are how much the engine can drive the crank. HP is kinda misleading to use as a unit of measurment though, because part of the direct equation to HP is weight.
HP has nothing to do with weight. It is based soley on RPMs and torque.
cstratton04 is offline   Reply With Quote
Old 07-05-2006, 10:40 AM   #22
newgensti
Scooby Newbie
 
Member#: 48906
Join Date: Nov 2003
Chapter/Region: Tri-State
Location: PA
Vehicle:
2004 STi
JBP

Default

Quote:
Originally Posted by ThrawlWRX
I couldn't see an N/A motor, a Turbo motor, and a S/C motor having anything similar as far as TQ curve. They could all have the same HP maybe... if you built them right. But The NA is going to have a linear band... The Turbo will start low and come up high for the topend. And the S/C would not be a strong down low as the NA ... nor have the top end of the Turbo... but it will have lots of mid range power... This is a bad question IMO... sorry. lol


I would have to say this is about right. if you had all the cars tuned to about 250hp they would all still have very different "powerbands" The tuned NA would probably be the quickest and easiest one to drive, Reasons being its lighter, no need for intercoolers uppipes downpipes turbos or anything, and because there is no wait for hte power to really hit. so it would net a nice smooth powerband.
Turbo would IMO be the most fun to drive because the feeling of hitting boost is just addicting. this car would be more sluggish down low, and have alot of top end power. Benefits of the turbo would be fuel mileage as you can drive around without hitting boost and still see some decent mileage.
S/C is nice because you dont have the lag of the turbo, the power is pretty much always there and this would be alot more like the tuned N/A powerband in terms of being smooth and they would probably both make their power in a similar fashion..

With all that being said, You would spend alot more money to make a NA with those numbers than just using a turbo or supercharger, and the turbo uses wasted power to make power where the supercharger takes energy from the engine to make more power. so the supercharger would have to make a little more boost to make the same power as a turbocharger. stressing the motor a little more and consuming more fuel. so all in all IMO turbo is still the best route to go. but like I said thats my opinion.
newgensti is offline   Reply With Quote
Old 07-05-2006, 11:08 AM   #23
Davenow
Scooby Guru
 
Member#: 23676
Join Date: Aug 2002
Chapter/Region: NESIC
Location: de_dust and Orgrimar
Vehicle:
.

Default

Quote:
Originally Posted by Izomorph
because part of the direct equation to HP is weight.
...

horsepower = rpm x torque / 5252

torque = 5252 x horsepower / rpm

I done see anything about weight in there.


As for the question, a hp is a hp. A lb/ft is a lb/ft

If you took 2389789423874897 vehicles, with identical hp and tq curves, they would all cross the line at exactly the same time. Im not sure how this is even a question. Power=power. Period. If 2 things have the same power propelling them, and they weigh the same, they are going to be dead equal. How can anyone even wonder about that??

For you dummies getting all bent saying there is no way they could all have the same curves, please say this out loud. THESE ARE THEORETICAL CARS, NOT REAL. Then slap the hell out of yourselves

Last edited by Davenow; 07-05-2006 at 11:13 AM.
Davenow is offline   Reply With Quote
Old 07-05-2006, 01:08 PM   #24
Calamity Jesus
Scooby Guru
 
Member#: 44501
Join Date: Oct 2003
Chapter/Region: South East
Location: in a minefield of caddishness.
Vehicle:
1984 "Skeletor from
"He-Man"

Default

Quote:
Originally Posted by Davenow
Then slap the hell out of yourselves [/size]
& tape it and put it on the intarwebs!
Calamity Jesus is offline   Reply With Quote
Old 07-05-2006, 02:02 PM   #25
BoneStockTS
Scooby Newbie
 
Member#: 80670
Join Date: Jan 2005
Default

I think this question arises from what the "muscle car" crowd will say sometimes (usually when their Z-28 has gotten its ass whupped for the millionth time by a japanese econobox), which is "Turbo horsepower is fake horsepower."

I.e. the only "real" horsepower is that of a naturally aspirated engine. One guy actually wrote a lengthy letter to the editor of one of the tuner mags saying this
BoneStockTS is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
This is cool and wrong at the same time WhiteLightning General Community 27 05-13-2004 04:56 PM
Is our 04 black color the same worldwide? DeeezNuuuts83 Newbies & FAQs 4 12-09-2003 09:39 AM
('93-'01) is bra for 97-99 the same as 01 rs? TheBaron862 Impreza Forum 5 07-08-2003 03:28 PM
Is 1990-98 Legacy Chassis the same? Dealer Xing Legacy Forum 2 04-11-2002 06:56 PM
This is ridiculous and funny at the same time youthanasia Vancouver Impreza Club Forum -- VIC 14 01-15-2001 12:39 AM


All times are GMT -4. The time now is 03:01 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.