I didnt realize till after I posted that this intake had been discussed before. I hate it when people do that and I just did it myself.(Search first and ask questions later)

Since the thread is already hear I have a Question for the hardcore theory guys
As far as I understood it, the TPI functions based on the ressonance of the air flow(hence the name "tunned")
If this is the case I would immagine that some hopfully a lot of time and research was done to determine optimum runner diameter lenght plennum volume position of throttle body runner length valve size....... How do the aftermarket companies get away with in the case of FIRST INJECTIONS such disproportionatly large runners or siameessed runners, larger throttle bodies...stuff like that.
Ive learned from my experience that bigger is not always better when it comes to engines. It just seems to me that building TPI setups is sort of hit or miss unless one is very well funded. At the same time Im not going to argue with the 12.second TPI guys on the board. Time slips speak for themselves. If I had the money or time I would be TPI right with all of you.
Perhaps someone could give me a quick lesson in TPI theory.
Thanks

 

There is no right or wrong with runner length and diameter.
Obviously the factory put identical intakes on a variety of engine combinations (camshafts, heads, and even cubic inches).
The factory TPI works on everything from the 1986 peanut cammed 305 engine to the 91-92 aluminum headed 350 vette engines.

Changing the intake parameters will indeed change the air-flow characteristics at the intake valve (as will the camshaft & exhaust as well). The trick is to match your fuel delivery curve to your these airflow characteristics. That's not really a function of money at all... you just have to know what you're doing.

Clear as mud?

 

well runner length and diameter do have alot do with it. we have all seen that the factory TPI stuff is too narrow, and too long, to run a large duration cam. it doesn't support the upper RPM airflow needed for such a cam. with the factory TPI setup, you are limited in your cam selection, if you open that up, you can run a larger cam, and in turn make more HP on the upper end. as it is the TPI setup is great for making torque, which gets you out of the hole nicely, but fails give you the HP to really scream down the long half of the track

 

yeah I know that game I had the setup in my sig breathing through a stock tpi for a short while and it was the worst thing ever.
seeing all of this aftermarket tpi stuff just makes me curious because it seems like it would be too delicate of a balance to just go changing runners and stuff like that. I read somewhere that a very well engineered TPI system can actually make a small amount of boost at certian brief RPM ranges. Pretty cool stuff

 

i read something simaler before about theboost thing but it hink it was more of an explanation than anything.if i remember the pulse wave inside kinda builds then when you hit the "tuned" spot the velocity inside the runner is so great that when one valve closes the air builds pressure and gets pushed back out of the runner across to the other side.actually slighlty pressurizing the runner.i dont think it would be anything that would actually register as boost but im sure it helps.i probly forgot something or messed that up real bad.eric

 

that is exactly how it work, the sonic pulse form the valve closing on one side of the intake travels across to the other side. the reason it is called 'Tuned' port, is because the runner lenght determains what RPM range that 'pulse' reaches the other side. while it is great for the power at the RPM range, it hurts you at other engine speeds.

on a side note, if you were able to spin your TPI up to about 8k, you would get another pulse event to happen, and it should be stornger than that one that happens around 3500 rpm