I was wondering how they function differently and what would you recommend between the two?

 

Tuned Port Injection is a type of EFI. Its the setup with the long tube runners.

 

EFI = Electronic Fuel Injection. TPI is a form of EFI. Uses a computer and the injectors are electronically controlled.

 

same thing really. EFI uses a computer and external and internal engine sensors to compute how much fuel and how much spark to supply to the car considering how much air flow is coming it and what the temperature of the air is, and also how much fuel is not getting burned in the exhaust. TPI is a form of EFI... SFI, MPFI, TBI, CFI are all forms of EFI.

 

what if your car no longer has a tune port style intake....say a MR or a SR of sorts. then what is it?

 

...errr

still fuel injection

TPI is a form of EFI. Good rule of thumb here. If you still have fuel injectors pumping out fuel, that means you have EFI.

 

can i still call it tpi or do i have to call it something else?

 

e d i t e d . . .

yah what they said. lol

 

Yeah, I have kinda been wondering about that. Since I recently switched over to HSR I don't think I should mislead people by saying its TPI. I guess I will refer to it as just plain old fuel injection. If they want specifics I will say its HSR. Yeah, that'll make em dizzy.

"Efficient Fuel Injection or EFI", huh? Where did that come from? Well, I guess its more efficient than a carb sometimes...

 

Efficient Fuel Injection is what E.F.I. stands for. All fuel injection is EFI.

 

Doesn't EFI stand for Electronic Fuel Injection
At least that what I always thought
Would make sense.
Just my 2 cents

 

That is what it stands for!!

 

Well then why are people calling it Efficient Fuel Injection then

 

That's an excellent question...

 

Holy crap, you guys are for real

EFI= Electronic Fuel Injection

its "efficient" because it doesnt use gas like a carb does, it measures a pretty precise amount of fuel. That amount is calculated by the ecm by using tons of engine sensors.

Just cause TPI uses one injector per cyl doesnt make it TPI... SFI and MPFI use one injector per cyl also. Tunned Port refers to the tuned runners that bring air into the chamber by using ultrasonic waves; the runners are "tuned" to the frequency... thats about as much as I understand and about as easy as i can break it down.

Now to even further enhance your EFI smarts(or to make you even more confused), TPI is a batch fire system, where one bank(one side) of injectors fires all at once(i.e. left, right, left, right, etc...). The LT1 was batch fire till about 95 when it went to a sequential fuel injection, where each injector fired when it was the cyl's turn. Less fuel consumption = better mpg.

Now to bring you into the present day world, GM is working on 2 new systems (well one idea is old, and the other has only been a dream). #1 which is pretty cool is cylinder deactivation or better known as "Displacement on Demand" Basicly, when you are at cruzing speeds, and the engine load is low, the PCU shuts down half the engine, there for making a V-8 run on 4 cyls. Caddy tried it back in the 80's... didnt work since computers were as smart as a hand held calculater in todays standards. Now with better and faster computers, they can do this with out the person knowing about it. #2 which is even cooler is the advent of Direct Fuel Injection. Injectors put right into the the chamber. Both technologies are in the new V-12 that will start to show up in Escalades by the end of the year, or the begining of next. The DoD has been in testing for about 3 years now and direct FI is starting to become a reality. The new Corvette will get the DoD technology as will all Chevy and GMC trucks. You could posibly see trucks getting in the uppper 20's to mid 30's in gas milage, and the vette could be in the mid 40's as most of the c5's today with a 6spd can average 30's mpg. So a 500hp vette getting 40mpg... take that Honda.

 

Thats what i was going to say even i know that and im a tbi guy. TPI is just a form of inductuion like the LT1 and LS1 manifold are different shapes less restritive than a ls1 and lt1 intake (stock).

 

i hate 4 bangers to (not the wrx though) but when you said at cruising speeds they stop running 4 cyclinders then wont you be slower then since only 4 cyclinders are working not all 8 so then its like a 4 banger in a 3600 car.

 

No.. if your cruzing, why do you need a 400hp motor to make you do 60-80mph if there is not a lot of load on the engine? But when you get on it.. the ECM comes alive and will transfer back to all 8 or all 12, and they have it down so well that you wont notice a dam thing... *** I love cars.

 

Wow, this whole conversation could have ended after the 1st reply, when I stated TPI was a type of EFI with the long tube runners.

 

One correction...all injectors fire at once...both left and right side.

 

Not picking on you Al, but what "internal sensors" are you referring too? All sensors I know of can be accessed without going into the engine.

 

JMHO, but would still be considered TPI...just not "T'ed" as originally equipped, but "T'ed" to a different RPM range.

 

You're right!!! But isn't it fun to beat things around and pool our collective knowledge...

Well Warrior, did you find out what you were lookin for!!! Betcha did...

 

No, not really...why do the runners have to be long, in order to be considered tuned?

 

No... one side fires then the other. hence the "batch" as in the right batch and the left batch. but its so fast that they really could be considered together.

For the internal sensors, there are 2 internal knock sensors on LS1's... i try to include all forms of EFI. also there is an oil sensor that goes in the rear of the LS1 where the dist. used to be.

The mini, hsr, lt1 all run almost off the same short runner set up. gives more of a mid to high range. Best intake on a small block is the ls1. The LS1 is really the top of the game if you wana talk about small blocks. the LS2 seems to be even more promising, but its mostly based off the LS1 archtecture(sp?).

 

No, there's only one injector driver in the ECM, it fires all the injectors at the same time.

As far as knock sensors ..I guess I see your point, as well as CTS, etc, could be considered internal.

 

Well thats what it came with from the factory with so thats how I described it for him