HAI Experiment - Page 7 - Fuelly Forums

Android Users - Coming Soon! - Migrating from aCar 4.8 to 5.0

Reply
 
Thread Tools Display Modes
 
Old 03-24-2009, 11:11 AM   #61
Site Team / Moderator
 
Jay2TheRescue's Avatar
 
Join Date: Sep 2008
Location: Northern Virginia
Posts: 4,657
Country: United States
Location: Northern Virginia
You can also look at "The Beast" in my garage for stealthy aero mods.

In the summer I can hit the EPA highway rating in short trip, stop & go city driving.
__________________

__________________






Jay2TheRescue is offline   Reply With Quote
Old 03-24-2009, 11:35 AM   #62
Registered Member
 
Join Date: Nov 2007
Posts: 1,111
Country: United States
Send a message via AIM to dkjones96
Only in speed density systems does the IAT sensor actually effect the amount of fuel injected. In a mass flow EFI system IAT only really effects ignition timing.

So BEEF, your Cavalier will use it to adjust for fuel.

Just an FYI.
__________________

__________________
- Kyle
dkjones96 is offline   Reply With Quote
Old 03-24-2009, 12:04 PM   #63
Registered Member
 
GasSavers_BEEF's Avatar
 
Join Date: Apr 2008
Posts: 1,831
the way I understand it, the higher the temp, the less fuel is injected and it has the o2 as a double check (or feedback) unless you go into open loop at which time it uses a programmed fuel map and basically sucks gas.

I may be understanding it wrong. I can admit that but I don't have a mass air flow sensor, just the IAT.
__________________
Be the change you wish to see in the world
--Mahatma Gandhi



GasSavers_BEEF is offline   Reply With Quote
Old 03-24-2009, 12:04 PM   #64
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
NoveResource, on the tire pressure issue, you need to examine real data from experiments and long-term usage. You'll find that most of your concerns are entirely non-issues, and some are better instead of worse. I can provide that data from >400,000 miles experience with increased inflation pressure (usually to the sidewall-stamped limit). I started using increased pressure to alleviate many of the problems you fear come with increased pressure, back when I took pride in my ability to waste more gas than anyone else (of course, gas was under a dollar and I didn't have any bills). I used/use increased pressure on a 1997 Pontiac Grand Prix weighing 2800 pounds on 205/55R16 tires, a dumptruck, a Ford Econoline 250, a 4400 pound GMC full size pickup, a 26 foot travel trailer, a 3000 pound 2008 VW Rabbit, a 2000 Isuzu Rodeo, and nearly everything else I've driven since ~1999 or so.

Quote:
Originally Posted by NovaResource View Post
With 235-wide tires, that cost is uneven tire wear (more in the center, less on the edges) and an unsafe condition.
245/75-16 tires on my pickup. The first set was rated for 44psi and that's the pressure I ran. They wore evenly and I replaced them at 50,000 miles.

The second set were rated for 80psi. They were used tires that were sitting on another truck in the yard, which had been abandoned a few year prior. I ran the front at 80 and rear at 72. More than 72 in the rear and it gets squirrely in the rain or on sandy pavement. I got 50,000 miles out of those tires too.

All tires that followed were rated for 80psi too. I'm at 180,000 miles with perfectly even wear on my latest set.

Quote:
It causes smaller tire contact patches that can be dangerous in the rain and cause longer stopping distances.
The amount of pressure required for that in vehicles larger or heavier than a Civic is usually far more than the tires are rated for. Autocross racers and police cars run pressures from 60psi to 100psi for better handling (and in the case of police cars, pothole resistance which I'll describe next). For references on that data, look at quoted material in the first post in this thread:
http://www.gassavers.org/showthread.php?t=7712

Quote:
They are also more prone to blowout from road debris and pot holes (lots of them in PA roads).
No. Road debris/pot hole damage comes from the sidewall getting pinched ("snakebite") against the rim. Increased pressure makes it more difficult to flatten it against the rim and cut the sidewall. In 100,000 miles prior to my increased-inflation habits, I had lots of blowouts from pot holes and curbs that I disrespected. In the 400,000 miles since, I've had one, from a very tall, very sharp-edged NYC curb that I went far too fast over (I thought it wasn't so tall/sharp).

Puncture damage works differently (obviously) but in my extensive real-world experience I haven't measured an increase or decrease -- though a roadside plug repair can be done on an extra-inflated tire without reinflating and still be safe to drive to get properly patched and plugged, so it's convenient if you happen to notice the nail.

Quote:
Originally Posted by NovaResource View Post
Let's just say, I'm not willing to do modification to the aesthetics of the car for fuel economy. Yes, I know smaller and lighter wheels would help mileage but I not willing to go that far (yet, or at least with the Tucson).
It's possible to do aero mods without adversely affecting aesthetic value, and easy to do if you're willing to tolerate minimal aesthetic changes. My upper grille block is completely invisible behind the grille face. My lower grille block would look perfect if I had patience and the ability to make things look nice, but I'm entirely incapable of ever making anything look nice so it looks ok from far away (say, a roadside cop) but ugly up close. Then there's roof rack removal, and underbody stuff -- belly pans, enclosure of rear bumper areas, skid plates, etc.
__________________
This sig may return, some day.
theholycow is offline   Reply With Quote
Old 03-24-2009, 01:00 PM   #65
Registered Member
 
Join Date: Nov 2007
Posts: 1,111
Country: United States
Send a message via AIM to dkjones96
In your Cavalier the IAT and MAP are used to determine air density and that's calculated against TPS/RPM and confirmed with O2.

With a mass flow system the less dense the air the less the air flow meter reads and that amount is calculated against RPM/TPS then confirmed with O2.
__________________
- Kyle
dkjones96 is offline   Reply With Quote
Old 03-24-2009, 01:33 PM   #66
Senior Member
 
Join Date: Mar 2011
Posts: 446
Country: United States
Location: Charlotte nc
I wonder if my milage will be higher if I remove the 250 pounds or so of extra wheels tires and tools.
Philip1 is offline   Reply With Quote
Old 03-24-2009, 03:07 PM   #67
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
I wouldn't expect much, but 250 pounds in a 3100 pound Saturn might do the job. Saturns seem particularly sensitive to some things like that, weight might be one of them.
__________________
This sig may return, some day.
theholycow is offline   Reply With Quote
Old 03-24-2009, 04:18 PM   #68
Senior Member
 
Join Date: Mar 2011
Posts: 446
Country: United States
Location: Charlotte nc
Quote:
Originally Posted by theholycow View Post
I wouldn't expect much, but 250 pounds in a 3100 pound Saturn might do the job. Saturns seem particularly sensitive to some things like that, weight might be one of them.
I'm actually less concerned about the weight and more about the alignment the rear of this car toes out dramatically when the suspension is loaded so ditch the weight and the toe goes back to 0˚ regaining coasting ability.
Philip1 is offline   Reply With Quote
Old 03-24-2009, 07:10 PM   #69
Registered Member
 
Join Date: Apr 2008
Posts: 1,258
Country: United States
Location: wiliamsburg virigina
Quote:
Originally Posted by NovaResource View Post
Also something to consider with a WAI is the effect on the vehicles emissions. Warm, less-dense air burns less efficiently and can cause the level of NOx to go up in the exhaust and pollute the air.
That warm less dense air must be why my summer mileage is about 10% higher than winter. I should be able to hit a 70 MPG average this summer.
Compare that to the new 39 city 50 highway rating for my vehicle, 45 overall average, and its and automatic.

I also noticed in this thread you reference two tanks at 26 MPG. I guess it's just pure coincidence that they happened to be in warm temperatures.

Better mileage=lower emissions.

Warmer air=better atomization

regards
gary
__________________
R.I.D.E. is offline   Reply With Quote
Old 03-25-2009, 05:25 AM   #70
Registered Member
 
Join Date: Mar 2009
Posts: 93
Quote:
Originally Posted by R.I.D.E. View Post
That warm less dense air must be why my summer mileage is about 10% higher than winter. I should be able to hit a 70 MPG average this summer.
Compare that to the new 39 city 50 highway rating for my vehicle, 45 overall average, and its and automatic.
Mileage is better in the summer because the engine warms up quicker, not because it is ingesting warm air. Also, summer gas is different from winter gas.

Quote:
Originally Posted by R.I.D.E. View Post
I also noticed in this thread you reference two tanks at 26 MPG. I guess it's just pure coincidence that they happened to be in warm temperatures.
True but much of that improvement is due to the inaccuracy of filling the tank. My assumption is that I didn't fill the tank as much those times. Evidenced by lower mileage in the previous and next tankfulls . That's why you can't base mileage on one tank (especially when it's only 1 or 2 gallons). You have to base economy on the average over several tankfulls.

Quote:
Originally Posted by R.I.D.E. View Post
Better mileage=lower emissions.
Not always. If too lean you get higher NOx emissions.

Quote:
Originally Posted by R.I.D.E. View Post
Warmer air=better atomization
That was true for carbureted cars that didn't atomize fuel well. That's not the case with fuel injected car where fuel atomization is much better.
__________________

GasSavers_NovaResource 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Incorrect mileage calculation? tonedepear Fuelly Web Support and Community News 6 04-04-2011 01:04 AM
No EPA Est for 2007 Chrysler Town & Country jklaiber Fuelly Web Support and Community News 1 08-23-2008 01:15 AM
ecu wiring green swift General Fuel Topics 0 05-09-2008 05:04 PM
Memorial Day. Remember those who died for our country. CO ZX2 General Discussion (Off-Topic) 5 05-28-2007 07:42 AM
WTB: HX or VX Wheels GasSavers_DaX Wanted to Buy 6 07-12-2006 10:50 PM

Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 12:59 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.