i nkow you cant gain much horsepower by porting a 6 port engine and i heard that one reason was that the irons was not as thick as the t2 so i was thinking can you take a t2 centor housing do a large bridge port on it and swap it on the n/a 6 port engine and then also port the 6 port front and rear housing and make auxilary bridges on them . i was just wondering if it could work and what kind of hp gains you get

 

How bout you just leave the rest of the T2 engine attached to the irons when you swap em over?

seriously, what kind of power are you looking for out of an N/A? cuz if its much more than 200 you'd be better off turbo.....unless you've got a 6 port 20B that is

 

Nah, its BS. The castings are identical between the N/A and the TII's as far as the center plate is concerned.

 

But there is less room to port the NA center irons due to the EGR passage. I have broken through a couple in years past, learning where the limit was. It has nowhere near as much casting room as the turbo irons.

 

Around 20% on the stock EFI and manifold sytem. Considerably more if you want to go to a more radical setup.

The casting is the same as mentioned besides the EGR stuff...Wait a sec, wasn't it just J-spec centers that didn't have EGR?

I've never run into much trouble porting the center iron but then I don't do huge ports on primaries.

You can bridgeport the NA irons just as easily as the T2 irons. Use any template or measure yourself. Don't bother with an aux bridge only setup.

Any NA bridgeport engine will require a non-stock intake manifold.

 

Do not EVER BP the AUX that is major no no! Who ever came up with this idea recently needs hung but oh well. Just bp the motor if you want it bridged the port work does not differ much on the NA except the runner design is harder on the NA as it is much smaller then turbo. The S setup is a tad different as the main port is smaller overall but the NA has the AUX to counter for as well. IMHO looking at this type of setup I would BP the S iron main port 3-4 with minor work on the port itself allot in the runner then advance the P .5mm down .5m closing 1mm latter and work the runner. That setup will give you allot of usable power curve fun on street and still have the benefits you want from a bp.

 

yes bu the USDM TII was on the manifold. Consider S4

 

I blame the whole aux bridge craze on myself. I did it as an experiment (which, I might add, has worked out quite well for me ) and now everyone is doing it.

If you are going to make a bridgeported 6 port, do it right and go full bridge. Grab any bridgeport template and bridge the primaries, then bridge the secondary/aux port combination. What you end up with are 4 ports on the end irons (one aux, one secondary, and two eyebrow ports). This works out very well. Or use 4 port irons (though I don't see why a person would do that).

 

I never read your post on that Aaron. I have only got the repercussions of new members mostly younger crowd go off on aux bridging there motors and telling everyone to do it. :-/ I'm sure the concept never said such things lol

 

i was just wondrering because i bought 2 91 n/a rx7s and only have done minor mods i was gonna rebuild the other motor and wanted to do some porting to get more power also there are no egr vavles on the centor housing on these motors nor anywhere else

 

That is because the EGR did not exist on S5 for some reason.

 

Mazda didn't need to use EGR because of the large amount of "natural" EGR present in the rotary due to combustion chamber shape and port overlap.

 

so just to make sure i can bridgeport the centor housing on a 91 n/a just like a turbo 2

 

Yes