Top end power loss after headers
Originally Posted by LSGunZ28
Gas needs 14 : 1 to ignite.... then how did chrysler get away with their lean burn cars in the 80s. I know there were really bad, and knocked a whole lot. but how did the gas ignite?
ALso, you saying that chrysler had lean burn cars means nothing...what does that mean? did they run 20:1 or what?
Originally Posted by BrandonDrecksage
because gas need 14:7 to ignite optiminally. It can ignite at 10:1 to, but not all of the fuel is going to burn, hence a gassy smell. It'll also burn at 16:1, but you'll wind up melting a piston and killing your engine because less fuel makes the combustion hotter. Which will melt ****.
ALso, you saying that chrysler had lean burn cars means nothing...what does that mean? did they run 20:1 or what?
ALso, you saying that chrysler had lean burn cars means nothing...what does that mean? did they run 20:1 or what?
You can surely run at very lean AFR's. When you do that though you want to be at a cruise, not under load. If you run very lean at cruise its safe.When you are changing load on the engine(hitting throttle) you want to be at around 14.7, once the throttle and load settles down you can run it really lean.
There are lots of SD Open Loop tune guys that do just that. They tune it to run realy lean at cruise while running around 14.7 under part throttle load and nice and rich at WOT. To accomplish this the LTFT's are disabled.
There are lots of SD Open Loop tune guys that do just that. They tune it to run realy lean at cruise while running around 14.7 under part throttle load and nice and rich at WOT. To accomplish this the LTFT's are disabled.
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
Originally Posted by brad8266
You can surely run at very lean AFR's. When you do that though you want to be at a cruise, not under load. If you run very lean at cruise its safe.When you are changing load on the engine(hitting throttle) you want to be at around 14.7, once the throttle and load settles down you can run it really lean.
There are lots of SD Open Loop tune guys that do just that. They tune it to run realy lean at cruise while running around 14.7 under part throttle load and nice and rich at WOT. To accomplish this the LTFT's are disabled.
There are lots of SD Open Loop tune guys that do just that. They tune it to run realy lean at cruise while running around 14.7 under part throttle load and nice and rich at WOT. To accomplish this the LTFT's are disabled.
Crusing runs from the OLFA table, and then hitting the throttle goes into the PE table (-> but first VE table has been dialed in); also, never have to replace wornout/broken O2 or MAF sensors.
Originally Posted by joecar
That's what I do...
Crusing runs from the OLFA table, and then hitting the throttle goes into the PE table (-> but first VE table has been dialed in); also, never have to replace wornout/broken O2 or MAF sensors.
Crusing runs from the OLFA table, and then hitting the throttle goes into the PE table (-> but first VE table has been dialed in); also, never have to replace wornout/broken O2 or MAF sensors.
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
When you hit the throttle, you want richer than 14.7...
As you open up the throttle, you want it something like 13.0 or richer...
At peak torque you want 12.4 or so...
(the best AFR's will vary with each vehicle...)
running richer may also allow more advance without knocking.
But I'm sure you all know this already.
As you open up the throttle, you want it something like 13.0 or richer...
At peak torque you want 12.4 or so...
(the best AFR's will vary with each vehicle...)
running richer may also allow more advance without knocking.
But I'm sure you all know this already.
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
Originally Posted by brad8266
Lots of work though to get it right.
Log a few drives with a wideband (MAF-less and open-loop) and then correct the VE table; then adjust OLFA and PE tables for desired AFR values; wideband AFR will now match OLFA/PE very closely.
Edit: both HPTuners and EFILive software have the maps/tools to make this easy.
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Originally Posted by joecar
Oh, yeah you're right, the right tools make the process much easier/quicker.