in 1999 Mazda updated the Rx7, and one of the things they updated was the Turbos. However since the car came out we've learned there were two choices, the 255/265ps engine and the 280ps engine. only the 280ps engines got the updated turbos, the 255/265ps engines continued to get the same turbo set that the 92-98 cars had.

the two part numbers are
255/265ps N3C1-13-700A
280ps N3G1-13-700

the N3G1-13-700/280ps turbo set has different wheels in it, and abradable seals on the compressors.

the confusing part is that the new turbos are 100% compatible, all of the piping is interchangeable between the two. they also look very similar. i found a couple of manky used turbos for sale for comparison.

Parts Catalog, paper!


the N3G1 Turbo Set, notice the bolts that hold the compressor housings on? and the black seal in the compressor housing?





the N3C1-13-700A turbos. Compressor housing is held in with a giant snap ring, and the compressor housing is just bare aluminum





the N3G1 turbos are a nice upgrade, essentially its a better match to the engine, so its more responsive, and makes a little more power.

 

Nice! I don't think anyone has properly documented this with pictures.

There are 3 different production turbos - N3A1, N3C1, N3G1. N3A1 was the originals. Sometime around 94 or 95 they changed to the N3C1's - they have a higher nickel content in the turbine housings so they are MUCH less prone to cracking. They can still crack but nowhere as bad as the N3A1's.

Performance wise the N3A1 and N3C1 turbos are identical. Same size wheels, etc.

Also, I believe the N3C1 and up turbos have a slightly different coolant line on one side, I ran into this once. The casting is a little thicker so the pipe was slightly re-designed to fit.

N3C1 and N3G1 have the turbo pills built into the nipples on the compressor housing. N3A1 has the pills pushed into the hoses going from the compressor housing to the wastegate actuator.

N3A1 turbos have "green" wastegate actuators, whereas the other 2 are typically gold in color. But, these can be swapped out so it's not 100% foolproof. If you see gold at a quick glance they are probably later turbos.

Dale

 

Thanks, guys! Handy info, and finally some clarity.

 

parts catalog says the N3C1 arrived for 1994, and that pipe is different, did not know that. the thing that makes it hard is that a LOT of turbos were changed under warranty, sometimes more than one per car

 

^Yep. I'm helping a friend get a '93 back together that's been off the road a long time. He bought it in '95 as the second owner. He has N3C1 turbos, most likely the original owner had the turbos swapped out back in the day.

I remember hearing that Mazda had a LOT of full turbo swaps that were dealers scratching their heads on turbo control problems. Boost leak and turbos didn't make good boost? New turbos.

The FD was a warranty nightmare for Mazda I'm sure .

The rear/secondary turbo compressor housing has the part number on it (N3A1, C1, or G1) and that's a 90% positive way to identify what turbos you have. It's possible someone swapped compressor covers or swapped parts around, but that's not common.

Dale

 

Since I have a '92 RHD efini which almost certainly is on the stock, presumably n3a1 turbos which you say are prone to cracking, would it be a worthwhile investment to pick up this n3c1 aseembly I see for $200 on ebay right now? What do n3c1's generally go for?
Sounds like they aren't just a bolt-in fit due to those coolant line revisions. How big of a job is it to get it to fit?
I'll check later what my wastegate actuator color is just to confirm.

 

I ran into the coolant pipe differences earlier this year and captured the differences.

The bottom pipe has bends to fit around the thicker N3C1 turbos and should work on both N3A1 and N3C1. The top pipe will only fit on the N3A1 turbos. I don't have a set of N3G1's to test the fitment.

I believe both versions shared the same part number (N3A1-13-530).

 

the hose would pop off the white solenoid, and tech would replace turbos, it still wouldn't work, so they would change the turbos again, and then the 3rd time, usually they would have someone else look at it who would order a set of turbos, take them home and put the vacuum hose back on...

same stuff happened with the rear suspension clunks, if you change the right rear shock three times and it still clunks maybe its not the right rear shock!

i know of one car where they put an engine in it, and the tech swapped the ECT and fuel temp connectors, and so it didn't run right. dealership spent another 12K on engines, turbos, ecu's wiring harnii, etc, finally they call the FD guy, and for $500 he puts the connector in the right place...

 

The N3C1/N3G1 turbos work along with a different manifold heat shield as well. It hugs the manifold tighter to create room for that coolant pipe revision.

The turbos themselves also use a different heat shield(between turbos and LIM) in the later years.

 

* * *
N3C1 and N3G1 have the turbo pills built into the nipples on the compressor housing. N3A1 has the pills pushed into the hoses going from the compressor housing to the wastegate actuator.
* * *
Dale[/QUOTE]

My US market 1994 has its original N3C1 turbos, but with the pills in the hoses. I changed them when my mods resulted in overboost. My understanding is that the 1995s had pills built into the hose nipples, so maybe there were even more than 3 turbo variations.

 

That may have been a production change, not enough to fully bump the N3C1 to a new version but probably got an "A" on the end of the part number as a minor revision. That makes sense for that to change since it's probably cheaper/simpler for production.

Dale

 

What would happen if an N3G1 turbo set was hooked up to an engine with the hoses having pills in them? Overboost? Underboost?

 

I have only messed with the wastgate control pill to compensate for cold weather overboost from a downpipe and cat-back muffler. I didn't need to change the turbo precontrol pill and I'm not sure what that would do.

I suppose that if the wastgate control line nipple and the hose pill were of different diameters, the one with the smaller diameter would control. (smaller wastegate pill opening = more boost; no pill at all = least boost). If the nipple opening and the hose pill are the same diameter, boost would not change -- in theory.

 

Yeah, hard to say. It may either do nothing or overboost. Definitely not an ideal thing.

Dale