Warm Air or Fresh Air? - Fuelly Forums
Go Back   Fuelly Forums > Fuel Talk > General Fuel Topics
Search Today's Posts Mark Forums Read
Thread Tools Display Modes
Old 06-03-2008, 02:10 PM   #1
Registered Member
Join Date: Apr 2008
Posts: 689
Country: United States
Warm Air or Fresh Air?

My 1988 Escort 1.9L TBI has the old heat riser system that runs off of vaccumn. My question is if I blocked the door to get warm air from the exhaust manifold all of the time would that help my gas mileage or would it make it act more like a choke since it would not be getting any fresh cool air from road draft.

#47 on my way to #1
Ford Man is offline   Reply With Quote
Old 06-03-2008, 02:19 PM   #2
Registered Member
GasSavers_Erik's Avatar
Join Date: Nov 2006
Posts: 1,027
Country: United States
The passage through the heat riser will be free flowing enough so that the engine isn't "choked" (unless there is a mouse/mud dauber nest in the heat riser).

Your current system was designed so that the engine is always drawing air of a certain temp by mixing hot and fresh air. You could play around with it and do experiments to see if the factory setup is optimal or if you could do better with a max hot setting.

IMHO, I think that drawing only hot air on a hot day might be a little too hot.

GasSavers_Erik is offline   Reply With Quote
Old 06-04-2008, 08:26 AM   #3
Registered Member
kamesama980's Avatar
Join Date: Nov 2007
Posts: 742
Country: United States
Location: Columbus, IN, USA
Send a message via AIM to kamesama980 Send a message via Yahoo to kamesama980
my truck does the same thing, called a pre-heater hose. it's meant to maintain a certain intake air temperature because the ECU doesn't calculate air density from temperature to get mixture. in other words, CAI/WAI doesn't really do much to affect fuel usage, just mixture.

your ECU may or may not be set up that way so the effects may or may not be the same. it shouldn't be choked but you'll have to experiment to find what's best.
1991 Toyota Pickup 22R-E 2.4 I4/5 speed
1990 Toyota Cressida 7M-GE 3.0 I6/5-speed manual
mechanic, carpenter, stagehand, rigger, and know-it-all smartass
"You don't get to judge me for how I fix what you break"
kamesama980 is offline   Reply With Quote
Old 06-04-2008, 08:42 AM   #4
Registered Member
GasSavers_BEEF's Avatar
Join Date: Apr 2008
Posts: 1,831
there have been mixed opinions on this as far as warm air vs cool air (normal intake)

my car had good results and others have had no positive results. someone also mentioned some other sensor that could potentially be damaged by too high a temperature intake air (can't remember what it was called).

mine typically runs in the neighborhood of 135-150 deg. I did hit 160 once and I haven't had any issues with overheating (yet).

personally, I think it is worth a try just don't expect huge gains from it and do more research because of that one sensor I mentioned. I don't know if that is true or not, just what I heard.
Be the change you wish to see in the world
--Mahatma Gandhi

GasSavers_BEEF is offline   Reply With Quote

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 Milage Calcuatlion PatM Fuelly Web Support and Community News 4 07-17-2009 07:21 PM
Questions about getting HX rims for 99 civic. Compaq888 General Maintenance and Repair 8 06-05-2009 06:56 PM
Gallons per Mile? nerb Fuelly Web Support and Community News 1 11-12-2008 03:33 AM
diy recumbent skewbe People Powered 13 06-06-2008 03:53 PM
Throttle spring...pedal vs RPM? ZugyNA General Fuel Topics 17 08-01-2006 04:17 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -8. The time now is 09:45 PM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.