My Jdm motor is confusing me.
 

I swapped in a JDM motor that is suppost to be a S4 motor, but it looks like the Primary fuel rail has a Pluse damper built into it, which I thought was S5, there is a Knock sensor in the center iron. However the Turbo has a twin scroll actutor, the alt is a S4 plug style. I noticed this while I was changing a broken fuel line. I am not worried or anything just confuzzed. Is it just JDM or is it a s4.5 or something?

I suppose it is possible that in the last 13 years and it's travels from the factory, to probably a few different owners in another country, to it's journey 1/2way around the world to probably a few other people before you got it that there is the slightest chance that someone, somewhere, may have replaced a part or two on it.... I guess it's possible.

PD's came stock on S4's

In fact, PD's are stock on just about every car ever made.... I don't undestand why people pull them off.

Are the fuel rails cast aluminum or tube steel?
Cast aluminum = S4
Tube steel = S5
Also, JDM motors typically have the fuel routing backwards:
fuel line from fuel pump -> fuel filter -> *secondary fuel rail* -> *primary fuel rail* -> fuel line return back to fuel tank

The US-spec 13BT's always go primary fuel rail first and then secondary with the FPR in the secondary rail.


S4 = center iron
S5 = (rear?) rotor housing


Sounds straight up S4 to me...


-Ted

My reason is that my car on fire once already.
I don't want it to fail again.
It currently runs perfectly fine without it.
I don't want to go through the trauma when the dealer quoted me "$5,000" to fix everything...


-Ted

True... the aftermkt ones don't leak though.... bad design from the factory, but they still serve a purpose..... I datalogged FPSI @ 200htz with and w/o a PD, it makes a difference. If the harmonics line up with the duty cycle of larger injectors (say 2000cc ID's) , it can affect AFR's either way. Braided SS line doesn't help, and FPR's aren't designed to handle the quick changes in fuel pressure.... one of the reasons I went with the nylon braided lines, and put a PD on the end of teh secondary.

one is cast one is steel.

Wow, someone put together a mix-n-match special... :P


-Ted

This is why I was confused. I thought I also removed a PD when I swapped the motor. Which I thought was on the front of the secondary fuel rail but I maybe mistaken, it was years ago and I might be thinking about my N/A motor.