RC550s too long?
Thread Starter
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
I bought a set of RC550s from a member here, just went to install them and they're too long. Did I buy non-Miata RCs or is there something I am missing? I'm trying to use stock isolator, so that might be an issue.
I would search harder before posting a thread like this, but I have to leave for a racetrack in 36 hours and my motor isn't in the car, broken in, or tuned.
I would search harder before posting a thread like this, but I have to leave for a racetrack in 36 hours and my motor isn't in the car, broken in, or tuned.
on topic, dumb question but its a place to start. Did you get the bushings from the fuel-rail to head? I tried to put my fuel-rail in without them and the injectors were too long, then I found 3 black bushings saying "wtf are these for?!"


what motor, is it built, and what turbo? I know your planning something sneaky!
Joined: Jun 2005
Posts: 19,338
Total Cats: 574
From: Fake Virginia
do your o-ring ends seat in the rail out of the car?
do the isolators fit on the injector nozzle?
do the nozzle ends with isolators fit into the injector bores?
do the isolators fit on the injector nozzle?
do the nozzle ends with isolators fit into the injector bores?
Thread Starter
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
Matt, the o-rings pop into the fuel rail just fine. The isolators fit onto the injectors, but they seem a touch stretched. The isolator drops in with the injector attached, but the injector doesn't sit very low.
what motor, is it built, and what turbo? I know your planning something sneaky!

His Sig says "stock".
Joined: Jun 2005
Posts: 19,338
Total Cats: 574
From: Fake Virginia
I have RC550s and they fit just like stock. I believe you'll have around 4mm of nozzle sticking past the isolator.
I had 550 on my car for about 5 minutes, but they fit right in place.
i thought they were too long at one point, but I forgot to put those 3 stupid as little spacer thing in between the rail and head.
What part number are they??
i thought they were too long at one point, but I forgot to put those 3 stupid as little spacer thing in between the rail and head.
What part number are they??
Thread Starter
Joined: Nov 2006
Posts: 15,442
Total Cats: 2,106
From: Sunnyvale, CA
I am using low-impedance RC550s on a BP4W ('00) head with a Vishnu fuel rail and they fit fine. I just sent them out to be cleaned, but I was using the stock isolators and the nozzle was definately sticking out past the isolator - not much though.
--Ferdi
--Ferdi
here is a post I just saw about it. one of the members mention using washers to space the fuel rail.
https://www.miataturbo.net/forum/t35465/
https://www.miataturbo.net/forum/t35465/
What is the part number of the injector. I have 550's in my car and they fit using factory isolators, in fact the same one's I had on my RX7 460cc injectors and the stock injectors as well. I'm using a vishnu rail.
Joined: Jun 2005
Posts: 19,338
Total Cats: 574
From: Fake Virginia
Ditto on checking the part number and going to RCs site (or googling the PN).
I used DSM RC 550s when I had my NA and they seemed a bit shorter. The low impedance ones. I ditched the rail spacers and used washer and it worked fine.
Frank
I used DSM RC 550s when I had my NA and they seemed a bit shorter. The low impedance ones. I ditched the rail spacers and used washer and it worked fine.
Frank
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Sep 12, 2016 08:17 PM







Do RCs have proprietary isolators? Are the holes in the '99 head smaller than the ones for the '94?

