TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
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OK, from searching, I've found that the actual test/schraeder valve is a -4AN fitting. If I remove that ENTIRE valve/fitting altogether, I'd be left with a threaded hole in the fuel rail.
Does anyone know if THAT hole is also -4AN?
....I'm looking to get an adapter for a pressure gauge.
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Are you putting a gauge in the car or just on the rail? I just removed the schrader valve itself and left the fitting, then put on a -4AN 90 degree swivel fitting,braided line and -4AN to 1/8NPT adapter for mine.
I already have the gauge and a 90 elbow, terminating with a female 1/8 NPT fitting. Ideally, a male 1/8NPT (to fit the elbow) to a -4AN female (to go on the test port) would be what I'd get, but I can't seem to find that adapter. I HAVE found several Male to Male adapters with the various threads, hence my need to confirm the fuel rail threads.
I know Aeroquip makes a -4AN male to 1/8"NPT female adapter since I have one, I don't see why they wouldn't make the opposite. I found mine at a local speed shop. Worse case you may have to change your gauge but I'm pretty sure the fitting into the rail is 1/8"NPT.
OK, from searching, I've found that the actual test/schraeder valve is a -4AN fitting. If I remove that ENTIRE valve/fitting altogether, I'd be left with a threaded hole in the fuel rail.
It shares the same thread size and pitch as -4 AN, but it's not a -4 AN fitting itself.
If the hole is 1/8 NPT female, you can just use a 1/8 NPT to -4 AN adapter.
It shares the same thread size and pitch as -4 AN, but it's not a -4 AN fitting itself.
OK, see that makes sense. It doesn't LOOK like an AN fitting.
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If the hole is 1/8 NPT female, you can just use a 1/8 NPT to -4 AN adapter.
Are you asking about the hole in the fuel rail, or in my gauge elbow? I KNOW the elbow I have is 1/8 NPT. I do NOT know about the fuel rail hole.
If I get a male -4AN to male 1/8NPT, I could remove the test port, and all would be merry. I think. -but, as I've learned in other threads (thx apeiron), the AN fittings seal with the 37 degree flared end. If my fuel rail doesn't have an actual AN fitting, but simply the same threads, would it seal?
I thought you were talking about using a piece of hose when you mentioned AN to start with...
If you remove the test port, you'll be left with a (probably) 1/8 NPT female hole... then you'd use a 1/8 NPT street elbow, screw it into the rail, and then screw your gauge into that.
You could just get one of the gauges that screws directly to the rail fitting, remove the schrader valve itself and call it a day. Accel made them in the past.
If you remove the test port, you'll be left with a (probably) 1/8 NPT female hole... then you'd use a 1/8 NPT street elbow, screw it into the rail, and then screw your gauge into that.
If it IS in fact a 1/8 hole, then yes, what you suggest makes perfect sense. I thought I'd heard it was a -4 hole, which is why I brought up AN. But like you said, just because they're the same threads doesn't make it an AN fitting. Bottom line is I need to find out what size that hole is before I can get a sure answer as to what I need. Apeiron, you've been a big help on my two recent threads, thanks!
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You could just get one of the gauges that screws directly to the rail fitting, remove the schrader valve itself and call it a day. Accel made them in the past.
Mike, I've heard several people have had issues with the Accell gauge leaking. Not the fittings, but the actual Gauge itself. -but yeah, that would be the obvious choice.
The hole isnt -4AN. I'll see if I can verify what it is later, but its not AN. There's no seat down in the hole for it to seal to.
Yeah, that's what Apeiron was thinking too, and that makes sense. At this point I'm trying to verify the threads. Apeiron was thinking 1/8, but I thought I remember someone saying 1/4? Heck I dunno, and without pulling it out I can't tell. BUT-if you can find out I'd sure be appreciative!!!!!
I do not know the exact size but it is not tapered pipe thread. it is a straight thread with a o ring seal. a "standard type of fitting" goes in what i do not know.
I removed the internal check valve and had napa match the flair fitting to the 1/8" npt with an adaptor hose. flair on one end and npt on the other.
Little late here, but the thread is a 5/16-18. They used a washer/seal thing between the fitting and rail, its an aluminum washer with a seal cast into the washer. Its possible a metric thread will fit, but the size and spacing indicates a std thread.
On a callaway vette. the schraeder valve is removed and replace with an straight adapter piece ( looked store bought cause it was blue anodized). It converted to -4an.
It was needed to run a additional fuel line. Which supplied regulated fuel (FMU) for two added injectors, installed in the boost side, just pior to the Throttle body. Looked like a horizonal TBI.
Also remember 1/8 npt is a tapered thread and the o ring seal stuff is straight.
i used brass on my fuel rail, 1/8 npt to a t-fitting, on one port i put the factory test port schrader valve so that would still be available for manual gauge test at engine, on the other port i installed electric fuel pressure sensor from grand national turbo, that feeds electrical signal to digital gauge on dash. more than 10 years ago and no leaks. also used grand national fuel pump, it flows much better than stock and can keep up with higher fuel pressure.
If possible try avoid the Accel gauge for a permanent installation my Accel glass is broken/loose not leaking also another 3rdgen in Swedish comunity had leaks with Accel gauge,so it is a possible security hazard,now on i am only having it when testing the fuel pressure then it goes of the rail.
Only permanent i would recomend is a quality gauge set up with braided line and so on.
