Supercharger/Increased MPG? - Page 4 - Fuelly Forums

Click here to see important news regarding the aCar App

Go Back   Fuelly Forums > Fuel Talk > General Fuel Topics
Today's Posts Search Click Here to Login
Reply
 
Thread Tools Display Modes
 
Old 01-23-2010, 07:11 PM   #31
Registered Member
 
Snax's Avatar
 
Join Date: Mar 2007
Posts: 758
Country: United States
Quote:
Originally Posted by bobski View Post
. . .Yeah, I've seen that before as well. It would work, but would take way longer to spool up than it should, probably result in greater exhaust back pressure (compared to a manifold-mount turbo) and take way longer to pressurize all the charge piping running from the rear end of the car back up to the engine.
l . . a . . a . a . aa .aaaggggGGGGGGOOOO!

Such a system might actually be more efficient if it is used in it's primary design platform of trucks and SUVs. It's crap for acceleration performance relative to a header setup, but it would substitute very nicely for otherwise unneeded extra displacement when towing, allowing it to freewheel more or less when not needed.
__________________

__________________
LiberalImage.com

I think, therefore I doubt.
Snax is offline   Reply With Quote
Old 01-23-2010, 08:29 PM   #32
Registered Member
 
JanGeo's Avatar
 
Join Date: Jan 2006
Posts: 2,444
Country: United States
Location: Tiverton, RI
Send a message via Yahoo to JanGeo
Some of the xB turbo systems are mounted below the car because of the lack of room around the header since the exhaust comes out of the head between the fire wall and engine instead of in front of the engine. The problem is the turbo gets wet when you run through deep water puddles. The end result of adding a turbo is more strain on the engine and drive train . . . the Scion tC gets 160hp and they push them to 300-400+ HP and they really go fast but bottom line is you pay a lot for a few seconds less to accelerate beyond the speed limit - eventually blow up the engine or clutch and burn your brakes out.
There is one advantage of a supercharger and that's the low end boost that is there when you want to lug the engine or shift at low rpm. There was a system of compressed air in a tank charged up with a slow compressor that forces air into the intake on demand for the times when you need a burst of speed for 10 seconds that was pretty simple and cheap. Problem with pushing more air is you need to increase the injector volume and remap the A/F mixtures sometimes boost fuel pressure and volume in the fuel pump run intercooler cool things with engine oil, change it more often due to additional heat breaking it down faster. and the costs go on and on. Some turbo setups run $2000-$3000 plus installation labor and then you usually have to get stronger drive shafts and clutch right away. A lot of guys push first gear when turboed and break the tranny cases and blow the lay shafts right away. Money is better spend like I did improving the drive train efficiency so I get more power to the wheels and better mileage all the time.
__________________

JanGeo is offline   Reply With Quote
Old 01-23-2010, 09:47 PM   #33
Registered Member
 
GasSavers_bobski's Avatar
 
Join Date: May 2007
Posts: 463
Country: United States
I see what you're saying, but I don't think we're talking about turbo systems that triple the engine's power output. A small turbo will spool up quickly but only boost power and torque by 40-50%. Most drive trains can handle that just fine, so longevity becomes a matter of appropriate tuning.
GasSavers_bobski is offline   Reply With Quote
Old 01-23-2010, 10:00 PM   #34
Senior Member
 
FrugalFloyd's Avatar
 
Join Date: Dec 2009
Posts: 383
Country: United States
Location: Bay Area, CA
Quote:
Originally Posted by fowljesse View Post
I wish I could remember where to site it from, but it was proven that small turbos increased FE. I think it was on BMWs, or Mercedes.
It's probably the Ford Ecoboost series of engines that you're thinking of.
FrugalFloyd is offline   Reply With Quote
Old 01-25-2010, 04:50 AM   #35
Site Team
 
Join Date: Dec 2006
Posts: 659
Country: United States
Quote:
Originally Posted by bowtieguy View Post
i once watched the guys on Horsepower TV install a twin turbo on a corvette...at the rear of the vehicle.
There is a system for that, but the part that bothers me is running oil lines (to lubricate the turbo) all the way back there, not to mention the increased risk of damage due to speed bumps and road debris and whatnot. Performance-wise, you also have to remember that the exhaust gasses have cooled considerably by the time they get back there, which means they've also shrunk in volume (and velocity), so the turbocharger is quite inefficient.

Having said that, they can still work.

-BC
__________________
Think you are saving gas? Prove it by starting a Gas Log, then conduct a proper experiment.
bobc455 is offline   Reply With Quote
Old 01-25-2010, 07:02 AM   #36
Registered Member
 
theholycow's Avatar
 
Join Date: Apr 2008
Posts: 6,624
Country: United States
Send a message via ICQ to theholycow Send a message via AIM to theholycow Send a message via MSN to theholycow Send a message via Yahoo to theholycow
Wouldn't the shrunken, slower exhaust gases have more force per volume because of the increased density? I suspect you'd just need the turbocharger to be designed differently to make use of that.
__________________
This sig may return, some day.
theholycow is offline   Reply With Quote
Old 01-25-2010, 10:16 AM   #37
Registered Member
 
GasSavers_bobski's Avatar
 
Join Date: May 2007
Posts: 463
Country: United States
Yeah. You would have a more even, consistent exhaust stream, but you're still losing some portion of the pressure, velocity and/or thermal energy that the turbine makes use of. If you could keep the turbine close to the engine but feed it a constant stream of gasses, it would likely perform similarly well. But to do that, you would need a non-cyclical engine of some sort... Something that doesn't use cylinders or closed combustion chambers... Something like this:
GasSavers_bobski is offline   Reply With Quote
Old 01-25-2010, 11:10 AM   #38
Registered Member
 
GasSavers_BEEF's Avatar
 
Join Date: Apr 2008
Posts: 1,831
thumbs up for 3-D moving graphics
__________________
Be the change you wish to see in the world
--Mahatma Gandhi



GasSavers_BEEF is offline   Reply With Quote
Old 01-26-2010, 12:13 PM   #39
Registered Member
 
Join Date: Nov 2007
Posts: 25
Quote:
Originally Posted by bobski View Post
Yep. The issue with superchargers is that they're on all the time and boost pressure is dependent on engine RPM rather than load..
This is not true, most superchargers utilize bypass valve assembly which bleeds boost depending on throttle position.
__________________
GasSavers_broadwayline is offline   Reply With Quote
Old 01-26-2010, 12:17 PM   #40
Registered Member
 
GasSavers_BEEF's Avatar
 
Join Date: Apr 2008
Posts: 1,831
yea but you are still spinning the screw (or turbine or whatever)

the pulley isn't set up on a clutch (that I know of) so you still have parasitics.

it may not be compressing but it is still spinning. there may be a reduced load if there is no pressure being accumulated but the load is still there.

(load being drag on the belt thus HP required)
__________________

__________________
Be the change you wish to see in the world
--Mahatma Gandhi



GasSavers_BEEF is offline   Reply With Quote
Reply


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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Not very precise mpg calculation larjerr Fuelly Web Support and Community News 4 08-20-2012 02:03 AM
Tools you keep in the car? GasSavers_maximilian Experiments, Modifications and DIY 57 10-08-2009 09:41 PM
Keeping my distance in traffic khurt General Fuel Topics 8 09-07-2008 04:23 AM
When filling up today to check my mileage I had an issue. HondaTorneoSiR Experiments, Modifications and DIY 2 06-12-2008 07:28 AM
Electrical power and cars. DracoFelis Automotive News, Articles and Products 2 09-16-2006 02:31 PM

» Fuelly Android Apps
Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 09:32 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.