this may be retarded - TCCoA Forums
 
LinkBack Thread Tools
post #1 of 14 (permalink) Old 01-06-2004, 11:50 PM Thread Starter
 
Join Date: Sep 2002
Posts: 635
this may be retarded

but i have a question. ok, its regarding air. well, as we all know, the closer to sea level or below, the better a car will run because of the amount of air. to put it loosly. well, i go to school in lubbock and i beleive we are 3300' above sea level. what im curious about is, when it comes to engine size ie number of cylinders. does the amount of air effect one type of engine more than another. i mean, if you take a v-8 versus a 4. we have 2 more cylinders, so does that mean we need more air to produce power rather than a 4 cylinder? i mean, im taking a logical view at this, because im a logical person. But...do you get my drift at what im thinking??? slap me silly if this is a dumb thought of mine.

correction*** ok here you....*we have 2 times more cylinders"

Last edited by 97mn-12; 01-07-2004 at 11:47 AM.
97mn-12 is offline  
Sponsored Links
Advertisement
 
post #2 of 14 (permalink) Old 01-07-2004, 08:09 AM
1st Gear Poster
 
Join Date: Nov 2003
Location: DIAFA
Posts: 51
Note to Self: Don't let my kids go to school in Lubbock.
AustinCougar is offline  
post #3 of 14 (permalink) Old 01-07-2004, 08:18 AM
Seasoned PostWhore
 
JoeyICU's Avatar
 
Join Date: Aug 2002
Location: Syskesville MD
Age: 33
Posts: 2,894
Garage
well the v8 takes in more air at sea level so it would take in more air at 3000 feet....so it affects it the same across the board....the 4 banger takes in less then the 8 at sea level...and less at 3000 feet...a 4 cylinder thats somewhat pepy at sea level...say a civic EX DOHC 1.6 rated at 127hp...might feel very anemic at 3000 feet vs a 4.6 making 215hp at sea level...but they both would feel very down on power

1995 Ford Thunderbird 4.6 LX - SC wheels, enlarged rear sway bar, full sound system, cut mufflers, PST 1 1/8" rear bar, Eibachs, Mark 8 LCA's, Al housed 3.55 gearset, cut mufflers
2011 BMX X5 Xdrive50i - BMS Stage 1, Cut Muffler
2005 Jeep Grand Cherokee 5.7L-Her stock DD
1984 Ford F250 6.9 IDIT - head studs in progress
JoeyICU is offline  
Sponsored Links
Advertisement
 
post #4 of 14 (permalink) Old 01-07-2004, 09:38 AM
PostWhore
 
Join Date: Aug 2002
Location: LA aka NW FL
Posts: 1,544
I'm sure one of the engineers can find a formula to express this but my guess would be no - it doesn't affect one engine any more than another. The total air intake will be reduced the same amount in either engine given no changes other than altitude. In other words if the V8 makes 250 hp at sea level and suffers a 15% loss at altitude then the 4 banger making 150 hp at sea level would also suffer the same 15% loss. You might feel it a little more in the 4 cylinder since the altitude doesn't change the weight of the car and the V8 had a little hp to "spare" whereas the 4 cylinder was underpowered to start wih.

Think of a column of air over your intake, this column weighs a lot more at sea level than it does at 3300 feet (less of it overhead, shorter column) so it exerts more pressure on each square inch of your intake. When the valves open the combination of this pressure and the vacuum drawn by the cylinder will determine how much air gets into the combustion chamber during the time the valve is open. The overall amount of air at 3300' will be less simply because there is less pressure "helping" the air into the chambers. Call it negative boost for lack of me knowing the proper terms...
doodaa is offline  
post #5 of 14 (permalink) Old 01-07-2004, 11:14 AM
 
Join Date: Feb 2003
Posts: 123
Quote:
Originally posted by 97mn-12
...i mean, if you take a v-8 versus a 4. we have 2 more cylinders...
Are we talking about large values of 2?
Marcus is offline  
post #6 of 14 (permalink) Old 01-07-2004, 11:33 AM
Braincoating! It's what all the cool kids have!

Administrator
 
tbirdbrain's Avatar
 
Join Date: Oct 2003
Location: South Florida
Posts: 2,725
doodaa is correct.

I, for purposes of this thread, will refrain from putting on my professor’s cap (I am one).

I will however strongly suggest to the first poster of the thread to double
check that math next time

www.BRAINCOATING.com..... Powder & Ceramic Coating

WWW.PRESTONSBOOKS.BIZ..... Books at really great prices!
tbirdbrain is offline  
post #7 of 14 (permalink) Old 01-07-2004, 11:46 AM Thread Starter
 
Join Date: Sep 2002
Posts: 635
hahaha, im dislexic so excuse me for my math in the thread be all screwy. I know what i was thinking wasnt correct. but like i said, i think of stupid ish all the time and ponder on it. So i thought i would ask. i do see what yall are saying and its what i already knew.

Now...as far as going to school in lubbock. come on now, lubbock is a great place. im getting a BS in Electrical Engineering and im 1.5 years away from being done. as far as my math credentials go. i know my math. ive been through pre-cal, cal I, cal II, cal III, differential equations, and now for my last magic trick, linear algebra. anywyas, i know it was a dumb question but hey, what is they say, its only a dumb question if no one ask it or something?
97mn-12 is offline  
post #8 of 14 (permalink) Old 01-07-2004, 12:04 PM
Braincoating! It's what all the cool kids have!

Administrator
 
tbirdbrain's Avatar
 
Join Date: Oct 2003
Location: South Florida
Posts: 2,725
Having spent some part of my life studying EE and ME (I think is was during the
Mesozoic era) I know things cam become a blur.

That shall not lighten the scorn and ridicule that besets those who make funny mistakes.

The question wasn’t the least bit dumb, just the math

www.BRAINCOATING.com..... Powder & Ceramic Coating

WWW.PRESTONSBOOKS.BIZ..... Books at really great prices!
tbirdbrain is offline  
post #9 of 14 (permalink) Old 01-07-2004, 12:05 PM
 
Join Date: Feb 2003
Posts: 123
I don't usually go for the cheap jokes, spelling errors, etc. but I couldn't help myself. Especially after seeing AustinCougar's comment. I'm not going to bag on Texas Tech; my oldest sister went there, and she's pretty intelligent. Good luck with your studies; just hope that your profs don't see this post.

Marcus
Marcus is offline  
post #10 of 14 (permalink) Old 01-07-2004, 12:20 PM
Refrigerator Raider Hater
Moderator
 
GreenBird's Avatar
 
Join Date: Jul 2002
Location: Vermont
Age: 36
Posts: 11,719
Quote:
Originally posted by doodaa
In other words if the V8 makes 250 hp at sea level and suffers a 15% loss at altitude then the 4 banger making 150 hp at sea level would also suffer the same 15% loss.
Glad someone decided to answer his question.

Another way to think of it is that the air is less dense at high altitude. That means less oxygen in a given volume. This is whaat causes the loss in power, and our own loss of power, "altitude sickness"




Matt "Looks Like Egon" Davis
96 Alpine Green V8
98 Audi A8 4.2Q in Racing Green Totalled
02 Audi A8L 4.2Q in Black

I buy my OEM Ford parts at 10% over dealer cost from Steve in White Bear Lake, MN.
You drive "like a man possessed"... by a woman!
GreenBird is offline  
post #11 of 14 (permalink) Old 01-07-2004, 12:43 PM Thread Starter
 
Join Date: Sep 2002
Posts: 635
Marcus: thanx, yeh i just wanna get done and graduate soon.

like i said, i know all about how air density and crap like that. it was just one of those ideas i got in my head when i knew the answer, but yet wanted to hear something different.

ill take hell for my math mistake. it is kinda funny. ahhh well....
97mn-12 is offline  
post #12 of 14 (permalink) Old 01-07-2004, 01:41 PM
PostWhore
 
Join Date: Aug 2002
Location: LA aka NW FL
Posts: 1,544
Even being the butt of ridicule can be educational Don't let it worry you, only dumb question is one that you never ask.
doodaa is offline  
post #13 of 14 (permalink) Old 01-08-2004, 10:26 PM
 
Join Date: Jun 2003
Posts: 41
There is one good way to keep your car from feeling anemic at higher elevations. Shut the car off.

Shutting off the car and then restarting it again will make the computer relearn the air density, and it will compensate for the lack of oxygen. tha'ts what the BARO sensor is for.
chocolatekoolade is offline  
post #14 of 14 (permalink) Old 01-09-2004, 09:05 AM
 
Join Date: Dec 2003
Posts: 390
It can only compensate so far. The fact is that the air is less dense and contains less oxygen in a given volume. You also have lower air pressure, so when the car is trying to suck that air in, the lower pressure also pushes less volume of air through.

So, what you get is a lower volume of air going into the engine AND the volume that it DOES get contains less oxygen.

If you REALLY want to lessen the power loss, get a super/turbocharger. You'll still probably suffer a bit of loss, but it should be a lot lower than what you would get otherwise.
Avatar28 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the TCCoA Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome