Yea, its a stupid question, well, I'm a newbie, I'm allowed! Whats the easiest way to tell if the engine is TBI or a TPI? Also, which is better? (I believe, I know, but I'm not sure). I have a 91 Firebird, 305 V8. Thanx in advance for all help!
-JT

 

TPI(Tuned Port Injection) is a large intake.. with four tubes on each side of a silver center piece curving out and down.. sort of TBI(throttle body injection) looks like a normal carburetor and will have a round air cleaner on top. TPI is far better.

------------------
83 Z28--not a pretty site, sold thank goodness

74 Z28-- 383/400, green on black. pretty clean. FOR SALE!!!

 

If you have a big round thing covering half your engine you ahve TBI. And I would bet my money that you have TBI's since that's what 305 Birds came with.

 

The intake to a TPI is near the front, and the intake to a TBI is a cheap plastic hose thingy that goes towards the drivers side headlight (firebird)

 

This is TPI:

 

and this is TBI:

 

"with four tubes on each side of a silver center piece curving out and down"

What goes in these tubes?

I though TPI meant each cylinder has its own injector. And TBI only had one feeding all 8 cylinders. Shows how much I know

------------------
1988 Jet Black IROC
5.7L W/ 64000 miles
Flowmaster Exhaust
Fully Loaded
------------------

My IROC

 

The tubes cary air into the engine.


Your right each cylinder does get it's own injector. You can't see them in that picture but they are "under" the plenum. The TBI really has 2 injectors.

 

ohhhhhhhhhhhhhh, So I was right

------------------
1988 Jet Black IROC
5.7L W/ 64000 miles
Flowmaster Exhaust
Fully Loaded
------------------

My IROC

 

Thanks. It is very obvious now that it a TBI. Thanx esp to CaliCamaroRS for the pic, that really made it obvious!

 

No problemo, runnerslife.

------------------
-Dan
-1990 3.1L RS
-Mods? no
-Slow? yes
-Currently collecting parts for T5 swap