View Full Version : Forced induction into a 4cyl, or a 6cyl?
qwesterra
03-20-2003, 12:29 PM
I have a mighty question that has been boiling in my system for quite a while. I have asked ConVict like I always do, but we couldnt figure this out.
Lets say you have 2 cars, one is a 4 cyl and one is a V-6, both of which are naturally aspired, and have equivelant horsepower. 200 lets say. ceterus paribus, I inject 6psi of air into the engine for all rpms, which engine will give me more power? The 4 cyl, must have higher compression then the V-6, but the 6 has 2 more cylinders. Would I get more power out of the 4cyl or the V-6?
:dunno:
Z
ConVict
03-20-2003, 01:17 PM
Ya I'll just add somethings to this. The turbo is the same size running in both applications at the same PSI. Both motors are putting out the same hp rating because of the high compression in the 4cyl engine, and the relative low compression in the 6 cylinder engine.
buh_buh
03-20-2003, 01:22 PM
Originally posted by ConVict
Ya I'll just add somethings to this. The turbo is the same size running in both applications at the same PSI. Both motors are putting out the same hp rating because of the high compression in the 4cyl engine, and the relative low compression in the 6 cylinder engine. yes, hence.. ceterus paribus.
Originally posted by buh_buh
yes, hence.. ceterus paribus.
You need an asian to explain it to a white guy what ceteris paribus means...:dunno: :nut:
ConVict
03-20-2003, 01:38 PM
I guess so :dunno:
*sigh*
ceterus paribus is a term for "All else being equal"
three.eighteen.
03-20-2003, 10:45 PM
looks like someone enjoys econ...
GTS Jeff
03-20-2003, 10:54 PM
Originally posted by qwesterra
I have a mighty question that has been boiling in my system for quite a while. I have asked ConVict like I always do, but we couldnt figure this out.
Lets say you have 2 cars, one is a 4 cyl and one is a V-6, both of which are naturally aspired, and have equivelant horsepower. 200 lets say. ceterus paribus, I inject 6psi of air into the engine for all rpms, which engine will give me more power? The 4 cyl, must have higher compression then the V-6, but the 6 has 2 more cylinders. Would I get more power out of the 4cyl or the V-6?
:dunno:
Z for this post u get the shameful:
ha-ha!
Hollywood
03-20-2003, 11:04 PM
Originally posted by qwesterra
I have asked ConVict like I always do, but we couldnt figure this out.
Z
Not surprised....
6's weigh more. Even if all else is equal it's wayyyy to typical for a 6 to weigh more that it can not be tossed out as an equal. 6's generally make more torque, more easily as well. Picture a silvia engine inline turbo 4, and picture a skyline engine inline turbo 6. If anyone was ever given the choice of engines, the votes would all go for the skyline because it make more power, easier.
P.S. 90% of the time 6's exhaust tone sounds better two.
redline
03-21-2003, 09:23 AM
Originally posted by Hollywood
6's weigh more. Even if all else is equal it's wayyyy to typical for a 6 to weigh more that it can not be tossed out as an equal.
anyone know the weight of a VR6?
6's generally make more torque, more easily as well.
torque is more a factor of displacement and engine design then number of cyclinders. And since 99% of 6 cyclinders displace more the 4 cyclinders....
Picture a silvia engine inline turbo 4, and picture a skyline engine inline turbo 6. If anyone was ever given the choice of engines, the votes would all go for the skyline because it make more power, easier.
it makes more power cause it has more displacement and it the end of the day there is no replacement for displacement!
P.S. 90% of the time 6's exhaust tone sounds better two.
agreed!
MerfBall
03-21-2003, 09:39 AM
Originally posted by redline
anyone know the weight of a VR6?
For the Jetta:
GLS 2.0L 1,331 kg
1.9L TDI 1,365 kg
2.8L VR6 1,442 kg
1.8T 1,378 kg
redline
03-21-2003, 10:06 AM
I just want the engine weight?
Hollywood
03-21-2003, 10:10 AM
Originally posted by redline
torque is more a factor of displacement and engine design then number of cyclinders. And since 99% of 6 cyclinders displace more the 4 cyclinders....
it makes more power cause it has more displacement
Gee...........are you sure? DUH! :banghead:
qwesterra
03-21-2003, 12:04 PM
[QUOTE]Originally posted by GTS Jeff
[B] for this post u get the shameful:
WTF. I asked a simple question, huh? whats that? GTS Jeff knows all, but can answer the question. Dont run up here, saying stupid stuff like I get the shameful because I asked a question. Well? C'mon GTS answer it, this post got completely off topic here, can anyone answer it? Its a damn good question, and its more then worthy to put on this forum, if anything it seems a little too advanced. No diss to anyone, but GTS Jeff answer this one smarty.
Z
Melinda
03-21-2003, 12:12 PM
I could be wrong here, but I'll take a stab at it.
I would think that the V-6 would get more power, especially if it's just the compression and the amount of cycles. Turbo's are the same size, but the V-6 does have the advantage...
I dunno, I'm tryin :) correct me if I'm wrong!
Melinda
jdmakkord
03-21-2003, 12:25 PM
I'd take an inline 6 over a v6
redline
03-21-2003, 12:38 PM
There is so many factors in this. It is hard to give a simple answer.
GTS Jeff
03-21-2003, 06:22 PM
Originally posted by qwesterra
[QUOTE]Originally posted by GTS Jeff
[B] for this post u get the shameful:
WTF. I asked a simple question, huh? whats that? GTS Jeff knows all, but can answer the question. Dont run up here, saying stupid stuff like I get the shameful because I asked a question. Well? C'mon GTS answer it, this post got completely off topic here, can anyone answer it? Its a damn good question, and its more then worthy to put on this forum, if anything it seems a little too advanced. No diss to anyone, but GTS Jeff answer this one smarty.
Z the reason i did not answer your question is because of this:
Originally posted by redline
There is so many factors in this. It is hard to give a simple answer.
thats right. i cant give a "good" answer to a "bad" question.
Hollywood
03-21-2003, 07:06 PM
Originally posted by GTS Jeff
thats right. i cant give a "good" answer to a "bad" question.
I don't think it's a bad question.
Originally posted by redline
There is so many factors in this. It is hard to give a simple answer.
Not really, the answer is easy. 6 is better generally speaking.
ConVict
03-21-2003, 07:14 PM
oowww Jeff goes down :thumbsup:
BigShow
03-21-2003, 07:22 PM
Originally posted by Melinda
I could be wrong here, but I'll take a stab at it.
I would think that the V-6 would get more power, especially if it's just the compression and the amount of cycles. Turbo's are the same size, but the V-6 does have the advantage...
I dunno, I'm tryin :) correct me if I'm wrong!
Melinda
Don't bother trying, unless you know what your talking about.
No truly good answers rely on a response of generally speaking
GTS Jeff
03-21-2003, 08:19 PM
Originally posted by Hollywood
I don't think it's a bad question.
Not really, the answer is easy. 6 is better generally speaking. so if i ask whats better, an apple or an orange "ceterus paribus "....u wouldnt shoot me down for asking a dumb question?
cuz thats sort of what qwest is asking here.
Originally posted by Hollywood
Not really, the answer is easy. 6 is better generally speaking.
In the real world if you ask me which would make more power I would agree with you.
In this case though you have a theoretical situation where you have a 4 and 6 cylinder are identical so I think they would be the same.
The reason a 6 cylinder would be better is because they generally have a larger displacement. On a purely theoretical basis, if everything is equal, meaning same displacement, ignition timing, turbo, etc, I think they would give identical numbers. When it comes down to it power only depends on one thing, the amount of oxygen you combust (and ignition timing). If those are the same, as they would be in this case, they should make the same power
Hollywood
03-22-2003, 02:16 PM
Originally posted by Ben
No truly good answers rely on a response of generally speaking
Why not?For ex: You can generaly say that honda's rev higher than other imports as a whole. That's "generaly speaking".
Originally posted by B18C
In the real world if you ask me which would make more power I would agree with you.
In this case though you have a theoretical situation where you have a 4 and 6 cylinder are identical so I think they would be the same.
The reason a 6 cylinder would be better is because they generally have a larger displacement. On a purely theoretical basis, if everything is equal, meaning same displacement, ignition timing, turbo, etc, I think they would give identical numbers. When it comes down to it power only depends on one thing, the amount of oxygen you combust (and ignition timing). If those are the same, as they would be in this case, they should make the same power
He basically did not get across the question he was asking properly. It's obvious all cant be equal in real world, since we are all in the real world he has to deal with some differences.
Alpine Autowerks
03-22-2003, 02:18 PM
One spec that would help answer the question is are the engines of equal displacement.
Torque is more closely related to the piston area than displacement.
The total useable work an engine does is best seen by comparing the area bounded on each engines HP curve taken from the lowest to highest rpm's being used.
5.9 R/T
03-22-2003, 04:02 PM
If ALL things are equal, I would have to say the 6. Your dealing with less air and fuel per cylinder which would make for a more efficent burn. All of this would be impossible to proove however, and you will never get the 'right' answer, since this is strictly theoretical.
qwesterra
03-22-2003, 11:04 PM
Originally posted by GTS Jeff
the reason i did not answer your question is because of this:
thats right. i cant give a "good" answer to a "bad" question.
Thats good, because I said all other factors the same, so what does that mean? it means all those "other factors" are the same! Wow what a concept, seems like other people can answer! So shut the trap if you cant say anything intellegent.
As for everyone else, thanks for the answers. There is the of the 2 more cyls making that much of a deal, but the 4 cyl has higher compression. Does the compression make not that big of an impact on the factors?
Z
GTS Jeff
03-23-2003, 12:52 PM
Originally posted by qwesterra
Thats good, because I said all other factors the same, so what does that mean? it means all those "other factors" are the same! Wow what a concept, seems like other people can answer! So shut the trap if you cant say anything intellegent.
As for everyone else, thanks for the answers. There is the of the 2 more cyls making that much of a deal, but the 4 cyl has higher compression. Does the compression make not that big of an impact on the factors?
Z sigh....HOW MUCH more compression? how is anyone supposed to answer your worthless junk questions if we dont know whether u mean 10:1 vs 8:1 or 14:1 vs 7:1???????????????????????????
and do u expect anyone to tell u te exact hp difference? the thing is, ceterus paribus cannot be applied when comparing a 4 and a 6 because so many things change when u go from 4 cylinders to 6 cylinders.
Originally posted by Hollywood
Why not?For ex: You can generaly say that honda's rev higher than other imports as a whole. That's "generaly speaking".
A good answer covers the 'why" sector as well.
Hollywood
03-23-2003, 04:02 PM
Originally posted by Ben
A good answer covers the 'why" sector as well.
Who say's I 'have to' give a good answer? :dunno:
Alpine Autowerks
03-23-2003, 05:10 PM
In engineering class the formula for power was PLANk=HP
P=bmep brake mean effective pressure (average pressure for power stroke)
L=stroke
A=piston area
N=revs/min
k=constant (used to accommodate such things as the units of measurements are in feet, inches or millimetres etc.)
In your example the 4 cyl is given a higher bmep by way of a higher compression ratio for reasons that are not clear. This would give it higher power ALL other things being equal.
More cylinders have higher internal friction but allow more valve perimeter for better breathing. There is a sweet spot for cylinder bores in the 92-97mm range for combustion efficiency
There is no mathematical reason for 1 engine layout to make more power than the other, the differences lie in the practicalities of packaging etc.
Originally posted by Hollywood
Who say's I 'have to' give a good answer? :dunno:
because you rant about there being a shitty tehnical section on here and yet people post incomplete or non descriptive answers, hahaha
you generally know what you're talking about...show it :thumbsup:
Powered by vBulletin® Version 4.2.4 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.