how can u tell which yr the a 6 port intake irons are by looking at them? i have a 6 port motor that has some s5 stuff on it but not sure if the intake irons are. thanx.

 

first question- what year was the N/A rx7 made , that will asnswer your question

the only irons to date in the 2nd gens that are diffrent are the s4t2 and s5 t2 rear irons otherwise you just have a 6port = n/a or 4 port = turbo, because the s5 are made with a wider casting

 

Do you have the intake/exhaust manifolds off where you can look at them?

 

the gaskets look much different take a pic of the intake u are questioning and we will help ya..

 

Here's a jpg of a series four rear side housing and intermediate housing.

See the intermediate housing? Right below the two primary intake ports is a Round hole. This hole on a series four has a *freeze plug* covering that hole. I know it's Not a real freeze plug. Just a descripiton of what it looks like. Well on a series five its a rectangular hole and open and that hole is for the ACV air to the exhaust ports on a series five.

The rear side housing for a series four is to the left. Compare it with what you have.

 

The S4 center iron has a EGR port next to the primary injectors while the S5 is cast completely flush and closed.

The S4 and S5 irons also have different front cover o-ring pedestals. The S4 is just big enough for the o-ring while the S5 is big enough for the o-ring and the tephlon retainer.

The casting around the oil filter pedestals are thicker on S5s as well. The last motor I tore down was an S5 NA block and there was a noticable difference in reinforcement between it and the S4 NA rear iron I had next to it.

 

Added jpg:

 

well the motor i got was a 6 port turbo frankestin motor, was wondering what parts they used. seems to be s5.