jhammons01

Everybody said that if you port you lose low end torque. I am assuming (you guys set me straight) it is due to the chamber being open longer and opening sooner after the intake and exhuast ports are opened up.

My question is this.

The porting jobs I have seen all are an attempt to open the intake allowing more fuel/air into the chamber. All the ports are shaped in a tear drop fashion with the large end closing fisrt and the rotor sweeping towards the small end of the tear drop. If the tear drop is longer (ported) then it would take longer for the chamber/rotor to close and begin to build compression.

I am assuming this to correct. If this is incorect hit the back button and read another thread, becuase it gets worse.

What if the port were in a different shape but just as big as any street port. Wouldn't you accomplish the same goal? What if the port were almost rectangular with rounded edges. The port would allow as much flow but the chamber would close just as soon.

RETed

This has been covered if you haven't seen those thread yet.
Check out NoPistons.COM, as they have a dedicated porting section there.


-Ted

syklone

Backwards. The small end closes first and the larger end later. That is why when porting, you extend the larg end up, keeping the port open longer. The port actually opens on the SIDE not on the end of the port, but closes on the larger end.

jhammons01

I am going to have to go down to Rotory Racing and get them to explain it better to me. I understand what you are saying but the TRUTH just confuses me at this point.

I am trying to port with out losing low end torque. That is why this question exists.

RETed

Minimize overlap and that should help...


-Ted

YearsOfDecay

OK... this is REALLY going to blow your mind........ you don't lose torque... you will alctually get more.... BUT... the curve is pushed into the higher rpm bands... thus... you "lose" it in the low end, but gain it back in the mid-high range.....

Think about the bell curve for tests... one geek gets a 100 and the whole thing shifts to the right... dropping a few hopefuls into the D range!!!!

Monkeying with the exhaust does the same thing..... hence all the crazy header designs out there for pistion cars... small tube stepped headers will give you good low end tourque, but will drop the high end because of flow restiction... Large tube straight headers will drop the low end, but come on in the high end...

Its the same for our cars... but its a different application.

A "street" port is designed to keep everything in the useable range of the motor, go to gonzo with the port job and cruzin around town becomes a pain in the ***. Just ask my buddy here with the peripheral port 1st gen...... that thing is WILD on the top end... but anything under 4K is like a retard on rollerskates....

Its some crazy stuff if you really start to get into it... if you open your exhuast and ports up too much... you can actually push the MAX HP numbers up out of the safe RPM range for the motor...... (like my buddy with the P-Port.. 10K... I'm scared of loosin my feet to flying rotors!!!!)

jhammons01

That's a good one. I want some more power. I still have not cracked open motor so there is still time to make changes.