>Pre-heating the incoming air may not be as much a problem on MPI's as
much
>as carbed and TBI engines. In those engines the atomized air can
>de-atomize in a cold manifold and cause stumbling and rough running
until
>the manifold heats up. The preheater warms the incoming air and helps
>prevent this problem.
Do the MPI engines have this preheater?? Seems to me the only hoses
plumbed to the air cleaner on the stock setup (at least on my '96) was
the intake tube from the grill area, and the 5/8" hose from the crankcase
breather...
>I suppose in a MPI system the fact that this atomization does not occur
>until the intake valve area this is not a problem but you are still
drawing
>very cold air for the first couple of blocks until the engine
compartment
>warms up.. Actually, the mod that effects the warmup even worse is
Again, how does the stock intake system compensate for the "ram-air"
induction tube that runs from the grill to the air cleaner?? Seems to
me, on a cold day, your engine would be breathing cold air constantly...
and who was it who said that colder air is denser and can actually
increase your peformance?? If there is such a thing as "too-cold" air,
wouldn't it be better to run the open-element air-cleaner in the winter,
thereby breathing the somewhat warmer engine-bay air, instead of the
forced-induction outside air??
>headers. Have not seen any new generation headers but I'm pretty sure
you
>will lose the exhaust pre-heater thermostat on the drivers side when you
>install headers. This gizmo closes when cold and forces exhaust through
>passages in your intake manifold. Again it is to warm the manifold up
>quickly to aid in atomization. So if you have both mods on a vehicle
that
>sees cold winters, you could have and engine that will warm up too
slowly
>and stumble around until warm.
Mine stumbles a little when it's cold anyway, but it did that even bone
stock... I thought somebody said they made some ignition changes, and
their truck ran TONS better, without that minor rough idle when cold...
Your point is well-taken on the pre-heater thermostat on the stock
exhaust manifolds. Hmm, I know there's a couple folks on the list that
have headers, but who has 'em that lives in a colder climate?? Oh yeah,
Bill Countie! HEY BILL, you've had your headers on thru summer and
winter, any driveability issues in the winter??? Do you remember having
to disconnect this "exhaust pre-heater thermostat" that we're talking
about??? What other info can you give us regarding the headers?? Sam,
any input??
>And yet another are the Chips that require a 160 degree thermostat.
Great
>in the sun belt but probably not too healthy in the snow belt.
Well, at least with the SBECs you can pull 'em out in the winter and go
back to the stock computer...
>Anything I have built up over the years was only driven in the summer so
>it's not a problem but if it's your daily driver and you live in colder
>climates the keep the old air cleaner and use it in the winter. These
Yep, good idea... I kept all my parts with the idea of putting the old
air cleaner, etc. back on for the winter months...
Ciao!
Ned Vogler
(nvogler@rghosp.chime.org)
'96 Dakota SLT V8 5-sp 4x4 Club Cab
Gibson 3" Catback Exhaust/MPI FIPK-clone
MSD Ignition & MPI Super Street TBI soon!
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 12:07:40 EDT