S4 vs S5 fuel rails - trying to install a Aeromotive FPR
 

I just noticed that S5 TII Fuel rails have no banjo bolts on the ends, because of this I can't remove the stock fpr (or pulsation dampner) whatever it's called.
can I just put S4 fuel rails on, and find a extra banjo bolt from another fuel rail to delete the fpr that's there? is that the only option or is it possible to remove the one on a S5 rail where there are no banjo bolts? it doesn't look like it will come off, but I can get the end welded shut if it's possble to do it, I would just rather know before destroying them.

S5 FPRs and PDs are integrated (ie not removable). I don't think the S4 TII secondary rail will bolt onto an S5 TII LIM. The mounting is a little different.

The S4 TII rail will fit the S5 Lower manifold BUT there is a 4mm difference.You need to raise the rail UP or the injectors get squished..Using some washers will do the trick.Put them between the rail mount and the lower manifold bolt holes and tighten.

I assume attempting to run both the stock S5 FPR and an aftermarket one would have intresting complications

Rising RPM makes a quality aftermarket fuel rail that seems to be highly regarded on rx7club: Rising RPM - Home

It looks like it is tailored to each specific configuration, eliminating the need to hack together some kind of s4 to s4 adapter

hmm..RisingRPM?..I "think" I have heard of them before!
Bob,If you look at the site Rising RPM - Home then hit the Fuel rail info.They State a 4mm spacer for s5.(that is where I got the info on size,But I put s4 rails on an s5 lower before).
Honestly,they make nice stuff,but if you are on a budget just get the s4 rails and hook up your Aeromotive on the end of it and call it a day.

omfg your engine is super sexy..
I was actoually looking at Rising RPM's fuel rails a few days ago.. I would get a set of them, but if it's quicker I will look for some S4 rails and just space them out then.

Spacing isn't even necessary. I converted to S5 LIM/UIM during my rebuild and I'm using the exact same S4 based parallel flow fuel system with no fitment issures whatsoever. In fact it actually fits much better now since the S5 UIM is taller.

I had previously spaced the fuel rail (using a ball bearing) because of the siemens 750cc injectors I was using, however I discoverd that the the injectors will slide deeper into the LIM than previously thought makeing the spacers obsolete.

Ull have to drill and retap the S4 rail to add the extra banjo bolt

why?They make screw in fittings with barbs on them.
I went with the aftermarket Parallel system that was posted on FC3s.org.
All the fittings just thread into the rail,no tapping ,no fuss.

hey, I ended up ordering RisingRPM fuel rails and block-off plates as well. Thanks for the link!

do you think it would be a bad idea to mix stainless fittings on the end of these aluminum rails?

I used my Earl's fittings on the rails.
you are going to notice that RPM uses a real Tight thread and that it will be snug to get fittings on,but they do seal up great.

I had less luck with the RRPM fuel rail pipe threads and two of mine leaked even with a few wraps of Teflon tape on my Earls fittings. I decided that under-tapped pipe threads and fuel fittings are a bad match and developed an alternate approach.

You should have no issues mixing stainless fittings and anodized Al threads.

Whats your alternate approach? :scratch:

I would also love to know :)

the FAQ's page on RisingRPM actually says that the fittings will not thread in all the way and that they designed it like that on purpose. I used teflon tape on mine and threaded the fittings until they were extremely tight and theres still about 3/8th of an inch of threads left on my fitting showing...no leaks after a 10 minute hard drive and 30 minutes of continuous fuel pump circulation leak test...

maybe you didnt thread enough or had bad teflon wrapping. :scratch:

I use a liquid thread sealer from permatex for all my threaded fuel lines. No leaks.

http://www.permatex.com/products/Aut...ad_Sealant.htm

If I told you I'd have to kill you (lol). Once I accumulate some miles on my newly built track car without leaks, I'll release my alternative into the wild. I'll mention that my solution doesn't use o-rings.

I found some bitchin videos on the rising RPM site, but didn't see a FAQ. Have a link?

I certainly could have cranked down on the Al NPT threads to seal them up, but didn't like the idea of damaging them to make them work.

While I've tried liquid sealant, I've generally had better luck with cheap and readily available Teflon tape (well...until now). I didn't try Permatex sealant though, so it might work fine. It doesn't appear to be rated for gasoline or E85 though.

Suggested Applications: Head bolts into through holes, oil PSI sending units and sensors, oil and coolant lines, fuel fittings, rear axle fill plug, brake and power steering fittings

I looked for a long time for a metric barb fitting. I would have needed an M12 x 1.25 as that is what the banjo bolt is. Never did find one...

Then I just decided to go with a banjo fitting/banjo bolt combo on an s4 primary rail. I used the spacer as well, everything fits fine.

BTW, The banjo bolt I special ordered from Mazda came in 3 days later, and didn't fit... but a forum member saved me and gave me back a part that I sold him months ago :) thanks Stevan.

look what showed up today!

I'd have to paint over the logo... though the actual parts look awesome!