DFI
Thread Starter
Heel & Toe
Joined: Aug 2001
Posts: 20
Likes: 0
From: Longisland N.Y
DFI
Im running a 383 with a Super ram, Trick flow 23 degree heads, a mild hydraulic
cam, and lots of other goodies. My question is Injector sizing i suspect the current 30
pounders are to big. (DFI cannot compensate?) I can drop fuel pressure from 50 to
42 pounds with no change in performance or fuel economy. I tried this in open and
closed loop no difference. Changing numbers in the fuel map doesn't seem to have
much effect. Thanks for any info in advance!! :confused:
cam, and lots of other goodies. My question is Injector sizing i suspect the current 30
pounders are to big. (DFI cannot compensate?) I can drop fuel pressure from 50 to
42 pounds with no change in performance or fuel economy. I tried this in open and
closed loop no difference. Changing numbers in the fuel map doesn't seem to have
much effect. Thanks for any info in advance!! :confused:
Advanced
Joined: Jul 2000
Posts: 72
Likes: 0
From: Bowling Green KY KY
Re: DFI (John Mattiace)
John,
Please be more specific. I have run 30's in small blocks all the time with no problems. What is your pulse width at hot idle in neutral (in milliseconds)? What is the closed loop correction telling you (is it always trying to pull out fuel)?
Did you just switch to DFI or the 30's?
Doug :chevy (I just felt like trying that thing!)
Please be more specific. I have run 30's in small blocks all the time with no problems. What is your pulse width at hot idle in neutral (in milliseconds)? What is the closed loop correction telling you (is it always trying to pull out fuel)?
Did you just switch to DFI or the 30's?
Doug :chevy (I just felt like trying that thing!)
Thread Starter
Heel & Toe
Joined: Aug 2001
Posts: 20
Likes: 0
From: Longisland N.Y
Re: DFI (Doug Flynn)
Pulse with reads 2.56 on average o2 reads 6.50-6.70 this is a hot idle in neutral. I
have the timing set at 36 total there is no ping that i can hear at full throttle. :smash:
have the timing set at 36 total there is no ping that i can hear at full throttle. :smash:
Thread Starter
Heel & Toe
Joined: Aug 2001
Posts: 20
Likes: 0
From: Longisland N.Y
Re: DFI (Doug Flynn)
The car runs great my problem is at full throttle and fuel economy.
The air ratio meter reads about 13.5 at steady speed's (off idle to about 50 mph)
this would very light on the throttle. No matter what i do to try and lean things out
it always runs rich. On full throttle it just berries the meter. I have tried making my
own map
i get the same results. If you happen to have the February 2001 Hot Rod issue they
featured a 350 (415 hp) i copied this motor. The only difference is i built a
383/10.01.
Some other things i have are Supper Ram,58mm throttle body, edelbrock headers,
big mouth lower, regulator, Holy 255 pump, 1.6 rockers, And a bunch of other
stuff.
Thanks in advance
The air ratio meter reads about 13.5 at steady speed's (off idle to about 50 mph)
this would very light on the throttle. No matter what i do to try and lean things out
it always runs rich. On full throttle it just berries the meter. I have tried making my
own map
i get the same results. If you happen to have the February 2001 Hot Rod issue they
featured a 350 (415 hp) i copied this motor. The only difference is i built a
383/10.01.
Some other things i have are Supper Ram,58mm throttle body, edelbrock headers,
big mouth lower, regulator, Holy 255 pump, 1.6 rockers, And a bunch of other
stuff.
Thanks in advance
Drifting
Joined: Oct 2000
Posts: 1,257
Likes: 6
From: San Jose, CA, USA
Re: DFI (John Mattiace)
At WOT the O2 sensor is quite confused. Don't worry about the bar graph at WOT. The only way to really dial in O2 is on a chassis dyno with a wideband O2 sensor. You want to shoot for ~12:1 through most of the the RPM range. You can also check plugs and MPH at the drag strip just like w/ a carb.
All this really points to the beauty of the new DFI w/ wideband O2 capability, don't it?
Scott
All this really points to the beauty of the new DFI w/ wideband O2 capability, don't it?
Scott
