what is the difference between the S4 and S5 iron housings and are they interchangable? i have an S4 with warped housings that i need to replace, i've found alot more S5 irons available than S4 and i just wanted to know what the difference is if any.

thanks.

 

i should have just bought a used motor.... but then it wouldn't be ported. =P

doesn't anyone feel like answering my questions or are they really that unique that no one knows?

 

S5 irons have more meat around mostly where it matters (dowel-pin areas). If you find more S5 irons go for it! See it as an upgrade! Yes, they are interchangeable.

 

They are phisically interchangeable, but the S4 irons (the middle iron) has the EGR where as the S5 do not. This will make a difference to your ECU.

 

Wait a minute.... you can't just change ONE housing.... the porting is different from s4 to s5 TII motors....

BUT.... since you mentioned that yours is ported already.... as long as you match all the ports, shouldn't be a problem.. (the runners from the LIM as well)

 

thanks for the input, the middle housing is the only housing that i can salvage so i'm not concerned with the EGR port, as far as porting i am using a RB port template and i am port matching the housings to the LIM. so hopefully if i pick up a set of S5 housings i won't have a problem.

 

car is 86 gxl n/a
engines involved are 86 na and 91 na

ok, so i was just wondering the same thing except a recommendation is needed if possible. i have s4 engine being rebuilt in winter. i have a full s5 engine at disposal. i might do the s5 manifold thingy but well see. so should i choose:

1. use s4 front, intermediate, rear irons with s5 rotors and accompanying housings (with appropriate weights of course).

2. rebuild the s5 engine and use my s4 front iron and just plug in all s4 everything else. no egr, problem? cali car, smog problem? by the way, would the power be up to par or comparable to s5's power if manifolds were used?

3. or recommendations on major parts from both s4 and s5 engines to make a better overall engine. i still need it to go into a s4 everything.

if i go with option 2, should be bit easier to use s5 manifolds (will s4 lim work on s5 block--want s4 LIM with the rest of s5 intake manifold). and still use rest of s4 stuff.

hopefully not highjacking the thread and hope info can compliment original post.