has anyone ever seen anybody cut square exaust ports into a turbo motor??

i bought a 13Brew outta a very hard running south florida FD (dynamic turbo's 10.50 sec FD)

when breaking the motor down to do a rebuild, i noticed that the motor had square exaust ports.



my engine builder laughed for like 10 mins. when he finally stoped laughing, he showed me an old racing beat book (or it may have been dowlings book) that had a line in it saying "when oppening up the exaust ports, be sure to square them up" the book meant to be sure that the ports were even. apparently Mr. C***** L**** of C** Racing in Miami took this the wrong way and cut SQUARE EXAUST PORTS.



my question is this, is there some kinda performance advantage to be had here? the guy who built the motor is well known in road racing circles, and had been building powerful rotaries for many years. does he know something i dont? or did he just make a mistake or what?



again, this motor put out 540rwhp in the FD and the car ran consistant 10.50's with a pettit ECU and an AIC. something had to be working right.....



anyway, i didn't have time to wait for my mech to port another set of housings, so i just let him enlarge the intake ports a lil more and told him to re-use the square ported housings....



any thoughts?



http://nopistons.net/albums/album51/aad.sized.jpg



heres my secondary intake port after porting, before polishing



http://nopistons.net/albums/album51/aab.sized.jpg



http://nopistons.net/albums/album51/aae.sized.jpg

i think it might be ok, cause the whole port is open at once? it obviously works



mike

tell your builder to do more research than just using an old racing beat book.



I have seen pictures of square exhaust ports posted before on other forums, nothing wrong with them....specially for very high power turbo engines.

damn that thing opens up real early. why'd he make it so big if the sleeve's still in there? i don't think the shape of the sides of the port matter too much.

Funny I did mine close.My top and sides are squared but i have a little bit more (not much) of a concave in the middle/bottom.Notice stock hight and width isnt much more.High boost fast release(why squeeze cause you start losing compression any way) to minimize exhuast in intake mix.

I dont think they are suposed to be "Square" and very big as the Apex will hit the edge Square on.



I know there is an Advantage of the ports that big but if it was me i would have shaped them a little or put a slight rad on the edges.

my builder was also concerned about seal breakage due to the sel hitting the edge flat like that....

any other opinions?

Nice looking housings you got there. https://www.nopistons.com/forums/pub...#>/biggrin.png

Hey, I recognize that motor!

I thought you were joking about the square exhaust ports. Have you called CLR to see what he thinks about it?

Best,

John

Rice Racing's Exhaust is'nt far off the same size.