Chevy & GMC Vans

coolen wrote:sorry for sounding retarded here, but I'm confused

Could you please enlighten me on a TPI set up. I know what TBI is, and that W family engine CSFI? But not sure on the TPI.

Thanks!!
AND NO POKIN' FUN LOL

Well the older ones had 2 injectors and the newer one 96 and up I think has 6 injectors. I bought a multi-port set-up, No popet valves, from linder tech and find it a good alternative.

TPI is tuned port injection

Both are generally similar, the main difference is the LOOK, and the fact that TPI has injectors which feed each individual cylinder.

TPI engines generally produce more high RPM power where as TBI produces power off idle. For low end grunt I would run TBI personally.

potskie wrote:TPI is tuned port injection

Both are generally similar, the main difference is the LOOK, and the fact that TPI has injectors which feed each individual cylinder.

TPI engines generally produce more high RPM power where as TBI produces power off idle. For low end grunt I would run TBI personally.

Not as much so. The TPI is a serious torquer manifold, you're talking about an intake that gives a 305 350 like torque. In fact if you look at a TBI 350 it's only about 10 ft-lbs up from a TPI. A TPI with the same cam and same compression will make about 25 more HP and 40 more ft-lbs torque than a 305 TBI. Add a cam to that and the different becomes 50 more HP and similar torque. Long runners=low RPM tuning. The problem becomes on a "wet" intake like a TBI or a carb intake is that the fuel can fall out, but the TPI setup has the injectors by the head so you don't have to worry about this. Most carb runners are actually fairly short, there are a few rare ones out there that are long runner carbs from the factory (think very aggressive chryslers)

In fact for about 3-400hp (fuel becomes an issue after that) I would prefer to bulid a TBI setupdue to the fact that you can change its RPM calibration (the intake manifold) cheaply where as with a TPI it tops out quickly without expensive parts like a set of runners and fabrication or porting work on the intake. I can buy two Performer RPM intakes for about the price of one set of new SLP runners. That being said either way is a great way to go.

91AWDAstro wrote: CFSI.. that's knows as poor mans fuel injection. That's got a single fuel injector with a bunch of poppet valves at each cylinder.

You are confusing Central Port Injection (CPI) with Central Sequential Fuel Injection (CSFI). Both use poppets, but CSFI has a injector for each cylinder centrally located and sequenially fired. Compared to batch fired CPI.