Fordnatics List Archive

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Mail From: (email redacted) (Matt Silveira x257)

Hello again everyone,


Well, I would like to know if someone out there can point me to (or
perhaps can share with me) the formula to compute how air temperature
(in general) affects horsepower of an internal combustion engine. I am
assuming that a normally aspirated engine is affected by more dense
(cool) or less dense (hot) air and I would like to know to what degree
(withing 5 Deg. F) and +/- 10 horsepower. I am hoping that there is
something like this, as there is for sea-level H.P. computing vs.
high-altitude, etc.


(And I hope that you don't think *I'm* full of hot air.)

Now, with regard to the 4.0 liter engine I have been dealing with in my
Ranger:


I found some very interesting items which impacted engine performance
and pinging. The kind of items that are stupid, but nonetheless
critical (apparently) to the ignition and intake system.


1. I used, as Ford recommends, a VERY SMALL amount of dielectric
compound on the boots. Well, when I pulled the plugs to read them, I
noticed the engine developing a miss and viola', the plugs were
fouled. The plug's conductor (the part that snaps to the plug wire)
was coated with the dielectric stuff even though I DID NOT PUT IT
THERE! Apparently, the stuff migrates under heat and this would
definitely, negatively impact performance of the plug itself. A
thorough cleaning of the boot, new Autolite Platnums and WOW!

2. Yes, you SHOULD make sure the intake is CLEAN, the butterfly is
CLEAN, the EGR port is CLEAN, and the BYP port is CLEAN!. I used a
small wire brush (fine bristles) and a lot of patience.

3. The battery, under load, when temperature was HOT also had a
voltage drop. Not enough power for ECC system and IGNITION pack.

4. Remove the lousy baffle that obstructs the air intake to air box.

Now, the truck runs GREAT, still pings a when the temperature is HOT
but its not the teeth jarring rattle as before.

Now I just need to re-route air ducts. I am still considering water
injection (called Edelbrock and they said it would NOT affect the
system, they discontinued the production due to dismal sales, NOT
dismal performance- so they say. . .)


Until next time,


Matt Silveira
System Engineer
OSI
(email redacted)
"Opinions expressed are not necessarily those of my employer."

Thought for the week:


Try converting SONET to a Sonnet