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Been busy. I'll try and add some context to these pics. The last month has been a race to this weekend.
Started by debugging a low fuel pressure issue. Turns out I failed installing the walbro with the factory style o ring and it was dead heading and leaking in the tank. While I was in there also fixed my fuel float with some jbweld, glad I did because the fuel gauge is proving to be pretty important on this thing 😂 With that fixed I was able to put the rest of the engine bay together, after leak testing the system. All good there.
Also installed a fast acting IAT sensor from a triumph, which is a common FD mod. It's a specific small thread pitch and I wanted to use the OEM spot.
So I got the upper intake manifold on, ran all my vac lines, etc but hit a snag and the OEM intercooler pipes wouldn't fit. A pipe kit was like $250 for 2 basic *** pipes (FD stuff I guess), so I DIYd it with some silicone 90's, 45's and some straight aluminum pipe and my trusty bead roller. Came out great.
There were tons of other little things not pictured. Deleting the sequential control from the turbo Y pipe, refurbished my gReddy intakes that came with the car (they were super crusty and flaking weird chrome coating so I blacked em out). Made turbo intake and compressor outlet gaskets from a sheet of gasket material (you don't wanna know what those cost). Also had to source a throttle cable bracket since it turns out I didn't have one.
With the engine together I needed to put the rest back together so we could tune this thing. No reason to fire it up if it's not ready to drive. Rebuilt the shifter, new shift boots, and got the interior back together. Fixed some clips with jbweld, bought some sweet checkered carpets off eBay, put seats back in, etc. Put unicorn tears in the transmission and filled up the diff.
Then onto a string alignment, which came out perfectly I might add. Happy with that.
Buncha other little misc things too like giving it a once over, reinstalling chassis plugs I had pulled out for rust inspection and fluid film application. I'm sure there's more.
Got the ECU all setup, all sensors reading and baselined, made sure it could crank and sync, bled coolant beat I could and primed the oil system by pushing oil through the system with a big syringe thing I got on Amazon.
The night before our tuning date I decided to check the fans, which I assumed were working. Nah. Relay would click but no fan would come on. I had a spare set of fans that came with my radiator, so I plugged those in, still nada. So I started debugging the 4 (yes 4) relays that control the cooling fans. I found 2 wires fully corroded and disconnected from one of the relays.
Wired in some spades and repaired that, and fans still wouldn't come on. But now I heard 2 relays clicking. I pulled the fan plug and had 12v there, then for ***** tried my spare fans again.. and boom. Fans. So yeah broken relay AND a dead set of fans. When troubleshooting it's a rarity to have 2 things broken like that. I ended up staying up pretty late figuring that out.
Still not out of the woods yet I needed to swap the fans out, so I got up early and went at it. The intercooler, piping, battery box, and radiator cross bar all had to come out but I got it done in about 1.5 hours.
Then my boy @redursidae showed up for the first fire. I cut it close but was ready. Plan was to set base timing, fire it up, burp it and go for a drive asap. Base timing procedure is weird and scary but we tag teamed it. The FD basically has only 1 mark to check timing at -20btdc, so you gotta do this weird thing in link where you lock trailing timing at -20btdc, then set base timing to be locked at 0. It felt weird and we had to adjust the default value by a bit but looks like we nailed it.
First start Ricardo was tuning fuel and watching vitals. ****** fire off within 2 secs of cranking and made a sick smoke show. Anyways no bad leaks and clts were rising linearly, but I didn't feel any heat on the rad hose. About the time I was feeling concerned Ricardo let me know CLTs were running away and we shut it off.
Now I'm a rotary noob but I know overheating is really bad for these things. We let it cool a min and cranked without firing and the coolant burped and CLT came down, but the gauge was high 240s for a min there. Scary.
Now on rotaries when breaking them in often you won't be able to start them back up while hot until the motor is actually broken in. I.e. compression when hot is less than cold. This is why you always hot start a rotary to test compression, it tells you a lot more about engine health than a cold start. We let the motor cool down, cranking without spark intermittently to circulate coolant until it was down to 210 or so, the re enabled fuel and it fires right up. I was relieved. Then it finished burping and held perfect coolant temps from there out.
Once we had stable temps we got it on the ground and put the first 10 miles on it. All was going well and Ricardo was impressed with the car and how it's reacting already. Gave it a once over and went back out. After about 30 miles on it we started to give it light load and 4k rpms and the motor just kept getting happier and happier. By the end of the day we had 50 miles on it, mostly keeping it under 4k rpm and varying throttle and load. We saw 4psi part throttle and around 5k rpm max, once I think. Was generally being super easy on it but we wanted to get the tune good enough that I could drive it somewhat normally and finish break in. We got the secondary injectors to kick in and roughed in good enough that it's smooth and safe.
Ricardo being the boss he is also dialed in the hot start, which is perfect and fires up first crank with no throttle or bogging. Straight G. I'll let Ricardo leave some notes here but we were both super impressed with the motor, how much tw it makes, how responsive it is, etc. I think we're both rotor heads now. What a feeling.
Anyways I have a bit over 100 miles on it with no drama. First oil change had a sheen to it, as expected on break in, so hoping that looks better next change. The sheen in the oil combined with my oil pressure gauge on the dash dropping to near 0 gave me a panic attack so I bought and oil pressure test kit and tested it today. The oil pressure is bitching the these triangles are so smooth running that I think things are going well.
This **** kinda stresses me out but I'm thrilled with my first rotary experience so far, the engine is so smooth and I can't get over the noises and how it feels. Judging by how it feels already this thing should rip with some boost.
So far main problem is a leak at the oil pan. That won't be fun to fix, but once this motor survives break in I'll address that. My tach and water temp gauges are also broken and need addressed soon too. But for now I just wanna get more miles on it.
hahaha this thing is sooooo sick brothers. I thought rotaries were cool before, but now...oh boy do I like it. I'm thoroughly impressed with how smooth this engine is and the feels it gives. Just cool.
A note on base timing: the timing mark is 20 ATDC. To set base timing we lock the ignition at 0 BTDC, and set the trailing split to -20, which Links interprets as 20 ATDC. The timing light fires off the trailing coil.
Lots of things were learned, but overall tuning has been straightforward, and she likes fuel. The idle quality suffers quickly anywhere above 14AFR, so I've left it around 13.5 AFR for break-in, and will try for a little leaner after the engine breaks in. Not even trying 14.7 at cruise right now. Injector staging has been the only novelty. Staging is smoother than we expected, whether it's the ECU or modelled mode, I don't know. There is currently a lean spike when the secondaries come on but it's not felt by the butt-dyno. I'm thinking that's happening because of bad injector data, and well, it's not fully tuned.
Don't trust Nate on this taking it easy stuff. He smacked 6psi*.
*: 6psi for us is 120kPa. ~3psi at seal level. He did take it easy
Purely speculative since I haven't tuned a rotary, or staged injection for that matter, but it looks like you're asking for a lean/rich spike with how quickly you're transitioning from secondaries to primaries.
Interpolate them more like this amazing MS Paint log and I bet your afr will follow:
Thank you, Curly. Now that you pointed that out it is rather obvious . It will be tricky to get as smooth a transition like that with 550cc primaries and 2160cc secondaries, but there ought to be a way. I do know that the "accel" setting in the staging menu isn't the solution. That just made it fat for a split second before the secondaries came on, instead of lowering the lean spike.
Right now it’s only based off MAP, but it also has a lockout of 1.4ms of actual pulsewidth (if it believes the secondaries will be pulsed under that, it leaves them off). Using pulsewidth as an axis could help, or I was also considering using RPMxMAP, or MAPxAirMass or something like that. It seems that regardless of the axis I’ll have to let them pulse in their non-linear range to taper the duty cycle as you said.
Edit: Didn’t mean dwell, but pulse in their non-linear range.
I love this discussion, thanks for chiming in Curly. We've discussed going to a different primary injector so that the gap in size isn't so big. But I'm impressed with the power of the link so far and hope we can get it dialed - I just got these 550s cleaned and id rather not have to switch them out. Of course we also are hoping more accurate injector dead times will help, too. In the end we had very little time to play with injector staging and I'm sure Ricardo will get us there.
This thread never fails to entertain. Always huge updates with every post. Congrats on the first fire and break in! I was getting a little giddy just reading about it, you guys must have been amped in person haha!
Every time someone mentions rotaries I realize how little I know about them. I had no clue they had 2 sets of injectors, or that you need 2000+ CC injectors. That actually might make my '63 Chevy look economical.
Every time someone mentions rotaries I realize how little I know about them. I had no clue they had 2 sets of injectors, or that you need 2000+ CC injectors. That actually might make my '63 Chevy look economical.
Fuel efficiency is a part of it, but only a small one. 13b rotaries need big injectors because they make all of their power on only two rotors. Comparing it to something like an LS with 8 injectors, to make the same amount of power with the same amount of fuel you'd need injectors 4 times the size. The staged injection is a workaround for deficiencies in the injector technology of the late 80s and early 90s. Injectors only have so much dynamic range, the bigger they get the harder it is to run them at very low duty cycles for idle. Staged injection means you can idle on the primaries and only turn on the firehose when you get deep into the boost.
It's a bit more intuitive if you think of a 1.3L 2-rotor as being kind-of similar to a 2.5L inline 6. 6 combustion events per 720 degrees on the crank (eccentric) shaft, spaced 120 degrees apart, pumping about the same amount of air, making about the same amount of power (at least if you compare engines of the same vintage). You'll need the same amount of fuel, but on the rotary 3 of those "cylinders" are forced to share a single injector (or pair of staged injectors in this case).
This is also why rotaries are so abusive on ignition hardware, you need to run the coils at 3x the rate that you would on a piston engine.
Great way of putting that, Ian. Another way to think of it is more similar to a 2-stroke (though technically still a 4 stroke engine). There is no dead stroke (1 power stroke every 2 crank revolutions for a 4 stroke), thus no extra time to dwell the coils (or inject fuel). A rotary produces a power event every revolution of the eccentric shaft and because the phases overlap, there?s no ?pause? like a 4-stroke.
Hence the huge fuel injectors and ultra powerful IGN1a smart coils I'm running to keep this bad boy happy!
I'm at 250 miles on it now and just changed the oil again last night. Looks like the bearing shimmer in the oil is reducing already, which is a good sign for break-in. I cut open the filter and there were no chunks. All is moving along about as expected, though I am still pretty nervous. Car runs perfectly and I've brought it to work both days this week.
Oh so you ignore the oil filter contents after break-in on the Miata but you care enough about this thing to check em? Ok man, I see you
On the real, good stuff! Glad to hear all's well so far. I remember the first couple drives to work on my built BP were a little stressful. Told my dad the week before to be ready in case I needed a ride home lol.
Also damn, the exterior cleaned up nice. Definitely passes the 20ft phone pic test
Thanks Ed. Right now plans are basically to get it broken in, get it ripping (hoping for ~330+/- whp), and leave it nearly stock body-wise.
I've got a bunch of little things to fix as well - tach and coolant gauge in the cluster - some oil leaks, etc. But all of that is going to wait until I get this thing broken in and tuned on boost, I don't want to dump any more time into it until I feel like I'm in the clear on this fresh engine build.
Eventually I'd like to re-install A/C (everything is there under the dash, just the A/C parts that came with the car weren't usable). I'd also like to run water injection with the stock mounted intercooler to keep the rotary happy.
I've got the OEM front lip coming in and I'm keeping it on stock wheels for now. Some better tires are definitely on the agenda.
Eventual goals are potentially a 99spec bumper and wing, that's generally my favorite look for these - but I will say the OEM stuff is growing on me. I think I've mostly decided to pass on crazy body mods, since it's just such a damn sexy car - but I could always get bored and things could change.
Just hit 275 miles on it and going strong. That's super part throttle, 3-4k rpms, and just breathing on a bit of boost (3psi?). I think she's gonna rip.
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