has any body converted a tpi 305 to a tbi 305? if so, is it hard? what all do i need

 

Hehe, this has gotta be a joke, right?

 

usually most people go the other way with that swap. I would keep that TPI on there if i were you....

 

For an engine built to make power beyond 4,500 RPM TBI is better. . .

To swap to TBI you need to either re-pin the current harness or swap it for a TBI harness (I'd re-pin). Then a TBI ECM, TBI unit, and an intake manifold of our choice.

RBob.

 

why not just spend the cash and get a better tpi upper manifold? that would be better. not sure who makes them though.

 

So, you mean to tell me that a stock TBI unit has the air and fuel flow capacity to power an engine over 4500 better that stock TPI? Id lLOVE to see proof of that.

 

If you're looking to make the most amount of power, I'd look into a new intake like the stealthram or miniram or a dedicated TBI system. The stock one just doesn't have the gumption to get you what you need without modifying it heavily.

 

Both stock systems blow performance wise. Not to say you cant make power with each, but itll be harder then slapping a good carb on the motor. The 89 and below also suffered from the garbage stock MAF system (Ive owned, and reverse engineered these, so I can say this with reasonable confidence), which was almost as crappy as the stock TBI electronics. As far as proof, just look at the people who swap in ancient stock flat tappet cams. They get 180 HP cars with RPM peaks at 4500 RPM.

TBI does have one advantage in that its exactly like a carberator without any metering and the jets are replaced with fuel injectors, so it behaves exactly like a carberator. The 2" TBI is the same as a 650 CFM carb.

One of the major pitfalls with TBI is that there are fuel dynamics involved, which makes metering the fuel more difficult. This is also compounded by the fact that speed density was used, which makes the fueling more empirical. This all combines to make systems that run like crap if you just throw parts at them. Done properly, the systems run quite well. Its even possible to get the ease of use of a carb with some mods to how the fueling is done. My last system didnt even need tuning after a head and exhaust swap. Set the timing, started it up, and drove away.

 

I will say this. The TBI board is such a great board. What other board can you come to in a bad, miserable mood and feel so great about yourself after reading it.

Your right, I feel better already...

 

Both systems in their stock form suck. As has been proven on here a number of times, just by simply switching from a TBI to a TPI you net almost nothing in HP from it . . . that should be proof enough. However, as also mentioned, if you go to a Stealthram or a Miniram type setup it's entirely different. At the same time, by going to a Commander 950 TBI type system, I'm not sure if there's that much of a difference then either between the high dollar setups.

I will say this though, by spending $225 on a 2" TBI unit or even less for a 454 unit, you can easily support up to the 375 HP area. (FWIW - with my 2" TBI unit my peak HP starts at 4700 RPMs and is a plateau to 5700 RPMs before it falls off) Try to go spend $225 on a TPI parts and see if you can get it to support the same type of power levels.

Now the TPI certainly has better aftermarket support and if you ever want to go for forced induction, then TPI is the ticket . . . but in their stock form, the differences are what's in the motor, not what's on top.

 

Which why I asked why

 

Yeah, that's still an excellent question. Unless of course he just happens to have a TBI system lying around, spending the money to do the swap is kind of pointless in my book.

 

Im not arguing with anyone in this thread any longer... I dont have the patience. Prove this statment or retract it.

 

And it's still a stupid idea.

 

Thread closed for very obvious reasons.