Hi,

Took delivery of my 20b and got it up on an engine test stand. Before I am able to crank it over I need to find out some info about the standard fuel rail.



Can someone help identify the letters? I can only assume that there would be two inlets for primary and secondary fuel rails, a return line and the pressurisation line (that weird black box near throttle cabling).

Next is the 1st sensor for the water neck which has broken clean off and separated from the sensor unit and wire that goes to it. Possible a sensor that talks to the thermo fan? Not too sure,



Next is I think a water return line from the heater inside the firewall, not 100% sure...



Lastly, am I able to do something about my map sensor? I was thinking about making the hole larger, using a tap to try and get a small fitting onto it...

 

hmm.. interesting hardware used to bolt the trans up...

 

just high tensile steel bolts. its attached to an engine test stand that i've nearly finished building. hoping to fire the motor up in the next few weeks pending work.

 

based on the rotor housings... thats a small dowel pin land 20B

 

yep, a series motor. a759 i think it was.

 

A through E is the 20B's "Rats Nest". See the Green/White check valve on Line A? Unlike all other rotaries, the 20B routes the turbo oil feed, coolant feed and return through some of these hardlines too. As mine didn't come with it, I just used AN6 for the oil feed and some 3/8 hose (I think) for the coolant feed & return.

Are you planning for a standalone for the engine? If so, I'd ditch the solenoids and vacuum hardlines to go simplified sequential. Just make sure to keep the oil and coolant hardlines, you may need them. Might as well re-use the check valves and Tees If they're still good.

There's a few simplified sequential diagrams floating around the Haltech section. Depending on the car that it is going in, that should determine the space you have for new solenoids. I'm using GM ones in my 20B FC, with my own simplified sequential diagram based on the ones in the haltech section. Mounted them on the passenger side inner fender using the airflow meter mount holes. See for yourself in my build thread "The 12 Days of Rotormas".

Now, the coolant sensor you mentioned in the filler neck. That is to the A/C fan and is wired the same as the FC's system (turn on at 207). Part number is N370-18-840, a normal S5T2 part you can get from Mazdatrix.

The hose barb on your LIM is for the Split Air Pipe. Chris at Banzai Racing says that if you block off the ACV, you can leave the SAP open and it won't harm anything or create an intake leak. I'd block it off just to be sure though.

Your idea about the map sensor has been done before, but it will only be as strong as the plastic surrounding the fitting. Since these were on the driver's side of the Cosmo (Intake/Exhaust manifold side), they get baked from the 20B twins' massive heat. For the stock ECU, you'd be better off just getting a S5T2 map sensor as they're scaled the same, according to 87T-66. If going with a standalone, now's a good time to pick up a GM 3-Bar sensor. And be sure to make some heat shielding for the new sensor too

Might be a dumb question, but did you measure the pilot bearing recess depth? Early engines aren't counterbored as deep as the later ones, so you can't get a pilot bearing seal on with a stock pilot bearing. As soon as the pilot bearing is in all the way, it hits the end of the counterbore. GTORX7's C-series has the normal counterbore like a 13B while my Pre-A #352 is a shorter one. Found out yesterday that another Pre-A has the short counterbore as well. Here's the thread: https://www.rx7club.com/showthread.p...=pilot+bearing

When I find a suitable shorter pilot bearing, I'll put the info in my build thread "The 12 Days of Rotormas"