S4 Primary Fuel Rail On S5?
 

I've read a couple of threads where people have swapped on S5 rails on S5 T2's but none of them really answered my question, Rotary Evolution told me that if I replace the S5 rail with an S4 and do the banjo bolt mod it will most definatley fix my fuel leak. I just primed the pump and its for sure the primary rail's FPD.

So just to make sure, I can use a NA S4 Primary rails on a NA S5???
:lol:

Yes, just make sure you have that plastic insulator between the engine and the fuel rail.

I used S4 TII primary fuel rail on my S5 TII engine.

Thank you! Too bad Mazdatrix doesn't sell the S4 rail... Gotta find one in classifieds now. :scratch:

Reviving this real quick...
 

Was told I'd need an S4 UIM & LIM because the S4 primary rail wont clear the S5's UIM... :dunno:

i've heard people say it won't clear but i haven't actually run into that issue yet.

ill double check it when i get to the shop, since i have all the parts you'd need.

Was told I'd need an S4 UIM & LIM because the S4 primary rail wont clear the S5's UIM...

Oh, maybe.

I used S4 TII fuel rail with S5 TII LIM and FD S6 UIM.

I have to say-
if you take off the pulsation damper and do AN lines on a S4 primary fuel rail, it is hard to see how it won't clear. I mean, its just the difference in thickness between cast aluminum (S4) and pressed steel (S5). Since the UIM is also cast aluminum some grindy grind should suffice if the S4 primary rail touches it.

You can also get an aftermarket S4 style primary fuel rail for ~ $130 if you can't find a Mazda one. Still need the plastic insulator.

Ebay-

https://cimg5.ibsrv.net/gimg/www.rx7...f6f0d2ac73.jpg

Thank you so much man!! Hopefully I'll get this all sorted out...just need to keep reading!

Again thanks for all your help!

-Ben

pretty sure it was the PD that would hit, since it is deleted it is not an issue using the aluminum non turbo rail.

I'm gonna buy a Primary off eBay and test it out... if not I'll find an intake in the classifieds.

Thanks for the info!

don't switch intakes, you'd need to replace EVERYTHING on the intake and downgrade to an S4, which creates more problems than it solves.

Oh...that makes sense :facepalm:
If none of it works I'll just get an S5 rail off mazdatrix

or you could let me help you, since this is how i make a living... and it's totally awesome seeing other people get the sales. not that i guess i'm not used to it by now.

I'll take any help I can get hahah
This is my first rotary, I get how they work but the systems that mazda added go over my head...

S4 rails on S5 engine


https://cimg6.ibsrv.net/gimg/www.rx7...5b825f983b.jpg

damnit that's so clean... so it would clear an S5 uim with the AN line returns?

thats a turbo engine

there is some discrepancies with the non turbo UIM fitments but for the most part it was the S4 EGR from memory that wouldn't allow a S5 UIM to go onto an early block without some grinding or a blockoff plate.

yeah I see that now..


The aluminium rail doesn't look that much bigger like you said. Hopefully its just the FPD that doesn't clear.

the pulsation dampener is also on the opposite side of the rail on the non turbo but yes, eliminating it opens a bit more space.

but i'll double check and give you a better idea tonight after i can put it all together to see any potential fitment issues, though i don't recall there even being any in this case.

I really appreciate this man! Thank you so much.

I didn't see that you were trying this on an N/A, still should not be an issue.

Here is an S4 TII rail next to a S5 N/A, looked around for a S4 N/A but no luck.


https://cimg4.ibsrv.net/gimg/www.rx7...a16745af04.jpg

https://cimg5.ibsrv.net/gimg/www.rx7...d190f981ce.jpg

Thanks guys! I really do appreciate the help :bowdown:

the S4 primary rail will not fit under the S5 UIM with the PD on it(the PD itself is too large compared to the smaller S5 stamped one), i do have one already modified with a PD delete that fits just fine under the S5 UIM.

i verified it by mocking up a S4 rail onto an S5 block with S5 manifold.

Awesome man! This helps so much! I really appreciate you testing it out for me!!!

no problem

Thread Update!

Rail from RotaryEvolution got here! Super clean and super fast shipping. +1000 to him.

Got the old rail of annnnd! Broken injector caps and fuel rail spacer :burn:

The new parts should get here today though