I have no clue about how it works . Ok, brains give the injectors order to keep themselves open for some time and fuel pressure behind them gives a spray of fuel to intake runners .

Simo (aka LordMrFord ) knows better why and how this happens. Long story short, it just works, it's accurate and gives us a lots of opportunitys to improve our performance...

 Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)

Pressure sensor reads the manifold vacuum(or pressure) and RPM is taken from coil minus(somewhere else like crank trigger).

Injectors injects two or four time per engine round and 12x12 map tells how long injectors are open (~2-25 milliseconds).

You can also run in closed loop, when lambda (oxygen sensor in exhaust) corrects air/fuel-ratio.

There are manifold and coolant temperature sensors which also corrects ratio.

So MAP(Manifold Air Pressure)/RPM is most used and easiest way to control fuel.

Ford ('89 and up) uses MAF(Manifold Air Flow/RPM to get same results.



Ignition samelike, but easier.

It also reads MAP and RPM and is corrected by (a little) temp sensors. When we use spark throwing lottery machine called Distributor, it needs only RPM (like coil - or crank trigger or four 6mm bolts on damper), control box like Megasquirt, what tells when spark is throwed, ignition module (MSD, Crane HI-6, some Bosch....) to drive coil(Megasquirt II dont need modules) and coils and plugs.

When we don't use Dizzy, we need Crank Trigger to tell us, in what position engine internals are and multiple ignition modules.


Hyvinkää, FI

Stock Y-Block ignition map with a little high cruising speed advance.







Some Megasquirt wiring diagram, I dont remember what motor that was.







Ignition module modded on MS, Y Crank Trigger, some Renault coils and my mushroom valley.


Hyvinkää, FI

It should be noted that the term vacuum is a little misleading, hence pressure in parentheses. A vacuum by definition is a volume of space that is empty, a void. This never happens in an engine. Some people think of it as a negative pressure. This is understandable because many gauges start at zero, which is actually atmospheric pressure, with vacuum on one side of zero and pressure on the other. Logically, if the needle moves in the vacuum direction, it appears to be negative. What we call vacuum is actually a pressure which is less than atmospheric and to my knowledge, our current understanding of physics indicates that a negative pressure is impossible. If a pressure of 12psi is measured in the intake manifold at sea level, we call it a vacuum because it is less than 14.7psi. When it comes to supercharging and turbo charging, either of those devices producing 6psi means that the engine is actually getting 20.7psi. Here again, because of the way the gauges are set up, they will show only 6psi, but it is really 6psi above atmospheric.


Lawrenceville, GA

In that ignition map, 100 kpa is throttle wide open, when manifold got pressure is same as outside.

kpa 5 is very hard engine braking position, when manifold got max vacuum(smileyface).

When we go kpa 100 and above, then speedo needle goes southeast.


Hyvinkää, FI

Throttle position in an aircraft is read off a "Manifold Pressure Gauge" when the throttle is wide open at sea level on a standard day the gauge should read 29 in. hg.  Usually reads 28 though.

   God Bless.   Tim                           http://yblockguy.com/

350ci Y-Block FED "Elwood", 301ci Y-Block Unibody LSR "Jake", 312ci Y-Block '58 F-100, 338ci Y-Block powered Model A Tudor

tim@yblockguy.com  Visalia, California    Just west of the Sequoias

Which is equivalent to approx. 14.7 psi. As you gain altitude, you lose ambient pressure, and horsepower etc. 

Frank/Rebop

Bristol, In ( by Elkhart) 

Thanks for the explanation, fuel injected turbos are the way to make lots of streetable horsepower as demonstrated by this years HOT ROD drag week. Larry Larson's twin turbo Nova traveled 1200 miles on the highway and ran a 6.95 @ 209  at the track on 87 octane gas.  That may be on the edge, but a streetable, 10 second twin turbocharged Y-block car might be possible if you could get the head gaskets to live. It will be interesting how fast the altered will go, keep us posted.

http://www.youtube.com/watch?v=yH-y2mxYS6c 

Gary Ryan San Antonio.TX.

Slowly getting back to business . We should get that thing to FHRA American Car Show next weekend. Electrics still missing and those intercooler tubes interfere badly with that nose part. I have to slice and remake it totally, but that will happen after the show.

 Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)

Jyrki from Finland

And me wearing Jyrkis 3.2A/15 racing gears.

So, we are almost ready for July 9th...

 Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)