Is anyone here using 6 port "irons" in a turbo car? I was thinking of the idea: S5 TII rotors/housings/stationary gears with six port irons. This is just a question and I want to know what would be bad or good about this? I know most people say that the 6 port irons have less porting potential but I remember someone saying the 6 port irons have more 'timing' in them from the extra ports. First of all I guess it would have to be asked is it at all possible to do in the first place?

 

I certainly wouldn't do it. Once you see the size of the ports you can do on the TII intermediate versus what you can do on the NA, the clear winner is the TII. Same with the end plates. If you really need longer intake duration on the TII plates, you can heavily taper the top half of the port and extend it quite a bit.

 

can't you use the 6pi end irons with a TII middle irons?

this way you have some decent drivability but when you open the gas you get some nice port size going on?



and what about if you are making it just a streeter

would the 6pi plates be nice there for if you did want to keep stockish size ports and nice drivability with some better low end?

 

Thats just not true, T2 and NA center housings can be ported the exact same, t2's just start out bigger, but the casting is all there. On the secondarys there is WAY WAY more casting on the 6-port motor, more then you could ever use.

Attached is a pic of my primary port compared to stock. this is on an S5 NA center plate, and the port is not tapered, you could go up quite a bit more if you tapered it.

forum wont lt me post the image rite now..

 

Thats just not true, T2 and NA center housings can be ported the exact same, t2's just start out bigger, but the casting is all there. On the secondarys there is WAY WAY more casting on the 6-port motor, more then you could ever use.

Attached is a pic of my primary port compared to stock. this is on an S5 NA center plate, and the port is not tapered, you could go up quite a bit more if you tapered it.

forum wont lt me post the image rite now..

 

e-mail them to me santiagl@iluvmyrx7.com i'll host/post them up.


Santiago

 

this thread also has some pics of beefy NA primarys

http://www.nopistons.com/forums/inde...opic=36175&hl=


If santiiago can get my pics up, there a scan of a port tracing. On S5's you can reach in the water jacket with your finger and feel where the casting is. My ports are right up to the top of this. you can go past this with a very sharp angled taper if you want to go bigger. The casting on the bottom can be approximated by drawing a line along the upper edge (its angled up at about 45 degrees) of one of the water passages and across the plate. Its the water passage rite below the tension bolt hole thats right below the port. the bottom of my ports are just shy of this line. this only works on S5's, i have no experience porting an S4 yet, but based on the pics in the thread i linked they can go quite large as well.

 

drago86, my e-mail hasn't received any pictures. I think its acting funky. My box limit is 5 megs right now. If the pics are over that they won't go through. Otherwise send them to santiago1987rx7guy@hotmail.com

 

You're quite right. I realized what I said just after I posted, but didn't bother to correct myself. Looking at the TII and NA casting show them to be exactly the same...I got mixed up with my sentence and was thinking end plates as I was picturing the 6 port plates.

Sorry about the misinformation.

Stolen from Mazdatrix:

Casting from all '84-'92 13B intermediate


Note that there is just NOT a lot of room in general. You need to heavily taper the bottom of the port to avoid the water jacket (depending on how large you are going, of course). For example, with the Racing Beat 4 port template, you need to be seriously careful at the bottom of the port. The top can basically follow the template.

 

I just got the pics i'll have them up in a few minutes. my stupid e-mail sucks right now.

 

Aren't six ports better than four though? More air?

 

Not when the 4 are bigger then the 6.

 

but 4 arnt bigger then 6...

 

Have you measured? When you take everything into account (especially the runners) the 4 port irons appear "bigger". Unless it's just a trick of my eyes...If you did measure the surface area of the ports and volume of the runners, I would certainly be interested in hearing the numbers.

 

Now I'm curious...Does anyone have the comparison between the volume of the 4 port vs. 6 port runners? Total port area?

 

Unfortunatly i do not, but i can give you the port area and duration of a 6-port motor. My 6-port plates are allready ported all to hell, so i cant do runner volume, but i have a tracing of the stock ports i can use to get port area. If you can measure a turbo plate we could have a comparison.

regardless, 6-port end plates can be ported way bigger then 4 port end plates, especially when you siamease them. They are allready at 80 degrees atdc, a timming youd have to heavily taper a turbo plate to get too. But keep in mind that anything after 80 isnt going to gain you much of anything below 8kish rpm, so the main advantage would be the extra volume that comes from the fact that you dont have to taper the port like on a 4 port to hit a late closing time. This could be good or bad depending on at what rpm you want power..

 

The biggest issue isn't so much port area or timing differences but rather the amount of flow through the runners. The 6 port housings have really small runners that are horrible for flow and cause alot of turbulence at the port entrance. The 4 port runners, while smaller in overall volume than the 6 ports 2 runners, flows more air with less turbulence. However the added timing of the 6 port plates gives more time for more air to enter the engine. There are different ways of looking at it.

 

I agree with all of that. I do however think that once the die grinder is broken out, 6-port plates have more potential. 13b-re end plates are pretty huge as well. The runners are about the size of a 6-port plate's with both runners siameased.. huge.

 

Unfortunately, I don't have any stock TII irons that have not been ported. And my 6 port plates are bridged, so...

 

I've got some virgin pre '86 6-port end plates that i'll measure the volume of the entire runner later today for ya'll if you want. They have 10deg. less opening time than FC 6-ports though.

 

measure the ID of the 6th port runners too plaease, i think they are smaller diameter then FC's too.

also the runner volume isnt going to tell you much, because the 6-port runners are long so there gunna look vigger then they are, cross sectonal area is better.