My Q is what is tbi good for?? Does it have better gas mileage than that of a tpi, mpi, or efi. which one has the best gas mileage and performance?? thanks

 

TBI wont give you the performance of the TPI or the gas milage of it either but they best thing about it is its simplicity...very easy to modify and fix...also much easier to use it for aftermarket..300$ for a new holley compared to what itll cost you to fix up a TPI setup (big bills) plus the TBI is better for top end than TPI...

 

tbi was designed to be a simple to work on, reliable, strong toque, and good mileage engine for gm's trucks and full size cars.
like any platform it can be made to perform very well with some mods. in stock form it does not make as much power as tpi, but i was running heads up with 305tpis with only a few mods on my car.
there are a lot of free and cheap mods out there, justy look in the tech articles for hte ultimate tbi parts 1 & 2. hell, even the cam of choice is cheap, a stock LT1 cam can be picked up for $20-50 and installed for a huge power gain.
tbi has 2 big probs in stock form,
#1 swirl port heads pretty much suck. they aren't the worst heads gm ever made, but they aren't too great. they can be worked aroudn a little, but to achieve power levels above 230-240 at teh wheels you will likely need to get rind of them.
#2 the stock cam is plain old weak. it is way too small to get the most out of the motor.
it has been proven that for pretty cheap you can make a tbi car handle itself against a 350tpi car and even soem stock LT1's. right now there are only a few playing in that range, but many more are working on it.

later
tim

 

id say with the ultimate TBI mods, cam, intake, heads and n2o (know it seems like alot but if you really want power youd do it to an engine anyways) youd be leaving lt1s in the dust...gotta have a better suspension and rear tho or you wont be able to do **** gotta loose the 2.73s

 

Think of TBI as TPI but in wetflow design. It's a wet flow intake but with very good characteristics. The only down side is that a carb is better at atomizing the fuel at higher rpm operations. The TBI on the other hand uses the shearing action of the throttle blades to atomize the fuel VERY well and this gives great low-mid torque and highway fuel milage. It just works really well but again, it's speed density so if no eprom adjustments then you'll have problems making peak horsepower blah blah.

 

if you take the TBI unit itself off the car and clean it really well,it makes one hell of a paper weight and conversation piece.

 

My TBI car gets 2-4 mpg better than my TPI car.

 

your tpi car must need a tune up.

 

My tpi car needs a lot of things. The tbi car needs a tune up too. It misses sometimes, it could use some plug wires and a rotor, and a distributor cap.

But think about it, the tbi car has a 2.73 gear ratio and a peanut cam. The tpi car has a 3.42 ratio and has the cam with more lift and duration. The tbi should get better mileage.