so im picking up this 4 port renesis to drop into my 1st gen...

now, from what i have researched, the 4 port is the exact same as the 6 port just with the top port closed off...

so i could just (in theory) make a template from a 6 port renesis, and port it out to match, and open the extra 6 port runners also, wich is also still there but blocked off???

havnt picked up the motor yet, so i really cant just open it and take a look to see if its possible...

any help here???

 

To my knowledge, no templates are available to port any Renesis engine. It has been done to a couple of engines and it was found that the water jackets are too close to the ports. Specialized welding was required to fix the places where they broke through.

 

I think that the irons are cast difffrent than the 6 port irons.

 

If you or anyone else is interested in looking up some history on porting, search for porting posts by guitarjunky28 & rotarygod.

 

im not going to use a pre made template. you just lay a piece of paper over a 6 port and shade the whole area. the port will be darker on the edges.

im not going to be porting out any extra, Mazda pretty much took the ports as far as they can go. i just will be copying the 6 port onto the 4 port plate.

 

I believe there was a thread that said exactly that. I believe you can't just add 2 more ports to a 4 port.

 

If you try to just port out the 4 port irons to copy the 6 port engines, you are going to trash your housings when you hit water. You can port a little bit but not much at all and let me really emphasize "not much"! You are not going to get 6 port horsepower from a 4 port. Not even a ported one. Keep in mind I have ported a Renesis.

 

alright cool...i'll just see what i can get from this 4 port for now. and when i find a 6 port i'll swap it out.

in a 1st gen, should be good enough power. mine will weigh around 3500 with me in it. looking for 200 wheel. unported.

the only thing stock will be the core itself. nothing on the outside...

 

My 85 RX7 weighed about 2600 lbs. The 82 was about 100 lbs less. Swapping the engine, with a Renesis, shouldn't increase the weight that much.

 

also, there is no way you are going to get 200 at the wheels with a 4 port. unless you go turbo.

a realistic expectation of a 4 port is 125whp.

 

i meant to write 2400 with me in it...i dont know how i wrote 3500??? it weighs a little less than this now. but i plan on putting some interior back in.

and the 200 wheel was pointed towards the 6 port. also, 125? im pretty sure it will get more. maybe not reach 200WHP. but plenty close...

 

nope. 125whp is what to expect from a good running shape 4 port. 180whp is a good result from 6 port.

a cobb accessport ($700) might net you another 15whp.

 

here is a thread where a 4 port automatic dyno'd ~149whp after some tuning.

https://www.rx8club.com/showthread.p...highlight=dyno

 

125 rwhp is not a reasonable number. That's what many untuned auto RX-8's get. You can plan on it being more than that just due to the fact that it won't be coupled to an auto. On a manual transmission you could probably get around 160 rwhp if done properly. In a car that is 600+ lbs lighter than the RX-8, that's pretty nice. That's not a bad horsepower number but definitely attainable with a standard 13B. The 6 port could get upwards of 200+ rwhp with little to no effort.

 

Looks like the same castings with different machining as port timing and finish features like this are different between 4 and 6-port MSP's

 

The (outer housings) port runner on the 4 port engine is larger than the secondary port runners on the 6 port. The secondary ports on the 4 port close 10 degrees later than the 6 port secondaries.

 

the motor will be ran on a megasquirt. fully dyno tuned...

so the cobb access port will not be needed...

if i get 160-170 from this 4 port i'l be pretty damn happy. 6 port will come later on...