5.7L Hemi SMPI ?

[Oscurida]

Hello all! Was just curious if anyone know what the SMPI means. I did a vin check and it showed 5.7l hemi smpi which I don't know what does smoking means. If anyone knows, thanks for they info.

 

[cux211]

I believe it's sequential muti-port injection I could be wrong though

 

[smiley]

Correct


$miley

 

[Oscurida]

Thanks! Assuming that's good, I mean sounds good don't really know to much on that.

 

[Hornet]

Means it fires the injectors individually instead of batch firing all of them.
Done more for mile-age and emissions

 

[Oscurida]

Means it fires the injectors individually instead of batch firing all of them.
Done more for mile-age and emissions

Thanks for the info.

 

[smiley]

The computer controls nearly everything which is great when it works but obviously expensive when it does not.


$miley

 

[Hornet]

GM was one of the first to start using sequential injector firing,back on the Buick Grand Nationals in the 80's.
It's still fairly common to use batch firing to this day.
Batch firing the injectors means they all fire at the same time,while sequential injection just fires the individual injector for the cylinder that needs it.
Rick

 

[cux211]

that's funny I thought that was an old GM thing I thought that went by the way side years ago and most everything was direct injected now a days

 

[Hornet]

Only Ford and GM are playing with direct injection,Chrysler has said they'll wait on direct injection.
I don't think Chryco wants to spend the money yet to tool up new heads that'll handle direct injection.
It takes a re-designed head with a totally differant quench area
Ford so far is the leader in North American manufacture'rs leaping into direct injection.
Can't wait till Chrysler starts with direct injection,horsepower possibilities will expand noticably

 

[Savfil]

Is there any aftermarket way to do this on the Ram? Probably expensive if so...

 

[smiley]

5.7L HEMI has went from 345 HP to 395 HP in less than 10 years can only imagine what direct injection would do. Hard to beat reliability of Dodge V8 over the years. You might use a lot of gas but they last.


$miley

 

[Hornet]

Not easy to to do.
You need a totally re-designed head with an injector and a fuel puddle pocket built into the head and pistons + someway to mechanically boost the pressure up to around 2,000 psi or higher.
GM and Ford are using a mechanical pump based loosely off the old distributor drive idea to boost the pressure.
There's no electrical pump available yet that'll boost the pressures needed for directly injecting the fuel into the cylinder.

I think the post above is mistakenly thinking port injection is the same as direct injection,way differant.
You need fuel pressures that overcome cylinder pressures in direct injection,so you're looking at 2000 psi or higher,not 50 psi like a port injection system can get away with