Judge Ito

I was crusing and saw this thread on porting :yum: Ok shoot ahead with questions Ill try to help..

jspecracer7

Squared off ports? You do this to increase top end power right? If you round them up, you'll end up with a port that produces more torque? How about if you go higher with the port? Does that raise the power band higher?

Fd3BOOST

Yea I was just curios why you squared the tops of your ports so much.

How does this affect the enigne.



Is jspec correct? You'll get more top end power, and the rounder ones get more torque.?

Dragon

you have to watch how high you go with the top outer corner because the apex seal sweeps in and across that area, if you go too high you'll eat the ****** and do much damage to your engine, that's why most ports are rounded in that area, if you know what your doing you can square it off, but you need to keep at least a few mm's or corner seal ride area... Most of the Tork/power porting comes from how you shape the bowl in the bottom of the port and how wide you open up the runner leading up to the port.. Judge Ito, key us in on some more porting info as I'm always happy to learning more...

Judge Ito

I see members are doing some homework here. I have ported both styles(curved end vs squared end) I could tell you from dyno results that the Vosko style port,(squared and straight across) changed the hole power band in comparison to the other style of porting. More goes into porting a nice flow in the runners then port closing. Port closing will effect how much cfm you could get into the chamber before it closes, in return yes one type of closing has a difference over another style of closing the port. I have to pick up dy daughter at school. **** this is my kind of thread Ill be back..I have some more tips of personal experience that has made some real difference in dyno numbers. Ill be back..

jspecracer7

I've got good Sensei's....Dragon, Igy and Rutt have all helped me understand turbo and Rotary engines...



How about exhaust porting? What experiences did you have porting the exhaust ports? Going up is better right? I know it increases overlap, but top end power should increase as well.

Judge Ito

Ok Im back in a flash. Many factors go into peak power and torque. Intake manifold lenth, the size of the port runners, exhaust ports. Basically what I did was port one engine twice. One port with a curve port closing and one with the squared straight across. Using the same exhaust port,same intake manifold on the same engine. Results with the square port was a higher power band and a lower power band with the curved port closing. One engine made 465rwhp@6500 with 20lbs of boost with 11.3 to 1 A/F ratio, this was on the curved port closing. The squared port closing made 490rwhp@7500rpm with 20lbs of boost with the same 11.3 to 1 A/F ratio, and the curve was climing never fell off. on the 465rwhp the curve started to fall right after the 6500rpm mark.



Other factors go into porting an engine. Like I've had so many customers tell me: "Ito port my engine but I don't want to loose low rmp torque but I want alot of top end power" so I try to give them the best of both worlds. a mildly ported center side housing and a radical secondary port with the most amount of port closing time I could give the engine. A good example of that is Voskos engine. I used a mild primary port(center side housing,which is responsible for low rpm torque) and a wild secondary port with a decent amount of port closing timing. I have driving Voskos car, considering the huge turbo he has I really like his low rpm response, I think vosko likes it too.

Judge Ito

I wanted to add. If you take a look at voskos dyno sheet you will see that at 7200rpm the engine was making 416rwhp and the curve kept climing. I let the gas pedal go early since it was only the second dyno run and I wanted a reference point on voskos set up. I'm sure next dyno runs we will see some bigger power at a higher rpm level with the same 13lbs of boost.

Judge Ito

Is this the first engine you ported? if it is, you did a great job. I'm going to ask one big favor from you. Dont stop practicing, I feel we dont have enough rotorheads porting. I think we're a dying breed. I have a love hate relationship with porting engines. I love to port but hate the time it takes and how it breaks my back.

Fd3BOOST

It is the first one I did. Thanks for the compliment.

I got some good advice from Wargasm and Ray Wilson of PFS.

I had fun and will always be trying to learn more.