Laminar's RX-8 EcoBoost swap thread

[Laminar]

Ford likes the 10 spline.

Fortunately they got away from that around 2010.

MT-82 doesn't have the best reputation.

What's the #1 complaint? High rpm shift lockout, which makes sense for the Coyotes that rev above 7000rpm. I'll be shifting by 6000rpm max (turbos are DONE by then), so that won't affect me. And as part of this project I'm naturally doing all of the fixes people do to get them to shift better - shifter solid-mounted to trans case instead of soft-mounted to body, good fluid, braided steel hydraulic line, good clutch with proper preload and correctly-sized master, etc.

I'm not worried about strength at all, they regularly live behind 700hp+ Coyotes at 7000+rpm.

[Laminar]

Well I had ordered some 1/4" stainless plate from eBay like three weeks ago that has failed to show up, so I grabbed a bar of 3/4" wide by 1/4" thick mild steel from Menards and knocked out some ugly DI plug hold-down brackets. I threw the downpipes in place and connected the wideband system to the ECU.





I pulled out my timing light again to confirm timing as I had a nagging feeling in the back of my head that it wasn't right. Well, my stupid adjustable timing light struck again. The slightest breeze will turn the knob on the back to change where the light flashes. It looks like last time I bumped that knob and set my 0 degree mark based on a flash from the timing light that was offset by 20ish degrees. I triple checked the timing light and reset my timing offset. I decided to do another startup now that I had a good fuel pump in place and the DI plugs were secured.



I have a feeling that it's occasionally syncing on the wrong cycle still. Sometimes it will do that, sometimes it will fire right up. I was hoping that with the widebands in place I could get a quick picture of which direction to take a fuelling, but the Spartan3 controllers kept cycling on and off. Looks like there was a new firmware released in January that address this issue, so I need to update that.

Besides that, something is still off with the setup. Maybe I have a pair of ignition coil wires crossed somewhere - it sounds like it's only hitting on 4 or 5 cylinders and where it should alternate firing on each bank, I can hear bank 1 hitting twice before bank 2 hits.  I'll do an ignition coil check tonight and make sure my wiring is good.

None of the plugs looked much different from any of the others, all were black and sooty and dry.



Once I was done I grabbed a spare set of plugs I accidentally have lying around and threw those in, we'll see if they help at all.

[Laminar]

She revs! You can hear the moment the sixth cylinder finally decides to join the party.

[digitalsolo]

Heck yeah, congrats!

[Laminar]

Did a spring break trip with the fam last week but managed to sneak some time in on the weekends.

Got the coolant system plumbed up. This involved plugging the old output to the EGR cooler, the output to the trans cooler, looping the heater hoses, cutting out the cabin heater pump, then installing the reservoir and radiator.



I dumped a couple of gallons of distilled water in only to be reminded that all of my custom turbo coolant hoses were still loose, and some were missing the o-rings. Lost about a gallon to the floor over those...

I also had to bolt up the AC compressor and alternator so that I could throw the belt on it, all of which I luckily bought some years ago and had stuffed in a box.

Once I was able to run it for more than a minute at a time I was able to actually figure out the proper VVT settings and now I have it idling nicely at 625rpm just like factory. I made some rough changes to the fuel and timing table and got it to rev cleanly. (I fixed the off-idle stumble after this video  )



I was able to test the oil pressure control solenoid and it's definitely working - I can activate it and drop the oil pressure by 30+psi. I have a PWM table set up to emulate the factory setup. It's doing about 33psi at hot idle and spikes to 90+psi once revs increase.

Speaking of oil pressure, I found one of my AN hoses leaking and both drain pipes leaking. No real surprise on the drain pipes, I'm still horrible at TIG and those are oil-impregnated tiny wall tubes that are a nightmare to get right. I took the driver's side off and re-flowed a couple spots that appeared to be leaking. The passenger side is the one that drops down and then almost touches the starter. I blew through that pipe a couple of times trying to close up a pinhole  , might go back and redo that pipe to give myself a tiny bit more clearance to the starter. On the plus side I don't see the turbos blowing blue smoke so I think the drains are working for now. We'll see how things get when I really load up the engine.

The last thing I wanted to test was Link control of the boost solenoid. I confirmed the head-mounted vacuum pump was indeed creating vacuum, but when I would try and open the boost solenoid, nothing came through. I know the solenoid was working on the Megasquirt and I think I buzzed it with the Link when I first wired it up. I'm getting 12V on one pin and I'm definitely seeing the other pin change state when I simulate control, so I think the solenoid might be dead. Not sure if I fried it with a bad setting or what, but I ordered a replacement to see if it's a hardware issue.

Once I know I can control boost pressure, it will be time to start hacking up the firewall for final clearance and then I can finalize subframe mods, engine mounts, and wastegate actuator mounting.

[digitalsolo]

This is a ton of progress. This detail work is what takes forever, and you seem to be cooking through it quickly.

I just decided to TIG a 4AN fitting on the end of a clutch hard line to better serviceability in a tight area vs. a tube nut + coupler.   I may yet regret welding to old grimy brake lines similar to your turbo drains.  We'll see how upset future me is with current me...

[Laminar]

After a quick hiatus to get the M3 ready for autocross season, motorcycle de-winterized, and BIL's boat de-winterized, I got back on the RX-8 this weekend. I had originally decided to give up on my oil drain hardlines and ordered some -10 flex hoses from Aeroflow with the plan of going back to the -10 connectors I had on hand:
https://aeroflowperformance.com/af463-36-flexible-turbo-drain-hose-s-s

Once they finally showed up from somewhere in NZ or Australia, I realized there was no way they were going to work for me - there's enough length that the hose would have to point foward and head back to the drain, but pointing forward means dropping the level of the hose below the level of the drain port on the engine even further, which wasn't going to work. I went back to the SS bends I had bought and ended up deciding to redo the engine half of the tube.





I rotated the drain as much as I could and got the tube away from the starter solenoid hot terminal and up off of the starter motor. Got those welded up at the end of the day yesterday, I'll have to fit them up now that they've cooled down and see if I actually managed to capture all of the leaks. Then we'll be back to making noise.

In the meantime, I got my transmission fluid (I went with Motul DCTF, the Mustang guys seem to like it). And my Wilwood clutch master came in, so I'll need to adapt that to the firewall and clutch pedal. The stock RX-8 is 5/8" and the stock Mustang is 3/4" so I went with 3/4". I could have gone larger for a better release but that was my strategy with the M3 and it's a HEAVY clutch. I should probably pull the clutch pedal bracket and reinforce it so I don't have it break like they tend to do.

I think I have the body wiring integration figured out. I'll run a trunk battery and pull wiring up to the front where the original battery was. From that post I can run factory wiring to the fuse box and I can adapt wiring to the alternator, starter, steering, and whatever else. The bigger change is to the fuel system. I'll have a Ford FPDM in the trunk to PWM the fuel pump so I can maintain my returnless fuel system, big injectors, but still idle well. But when the FPDM module loses its PWM command from the ECU, it runs full speed for 3 seconds before shutting off. In the case of an ECU error or accident or something else going wrong. I DON'T want the fuel pump gushing for a few seconds, I need it shutting off. So I'll have a relay in front of the FPDM controlled off the factory wiring.

[digitalsolo]

Interesting on the FPDM, I should see what the GM one I'm using does.

[Laminar]

The RX-8 has an in-tank spillback valve that dumps pressure over 65psi. My test stand just has the pump plumbed directly to the rail. At one point I killed ECU power before fuel pump power and the FPDM did its fallback thing. I saw fuel pressure spike to well over 108psi. Glad my AN hoses held up, but luckily I won't have to deal with that in the car.

[Laminar]

Here's the passenger drain pipe in place:



You can see how the pipe covers up the bolt on the right that threads into the engine block. I notched the bracket so that I can have the bolt already threaded in place and slide the pipe in, then push it up into the turbo. Because it's higher and further back, I now clear the starter and solenoid.

[Laminar]

Got the new injectors installed last night.







I was pretty sure they were going to fit as this is the set recommended for the Raptor with dual injection and based on pictures and part numbers I could find the 3.5 and 2.7 injectors crossed over. Glad to see everything works. I considering going with a cheaper set where the supplier claims the set is flow matched, but it's nice to actually get results per-injector.



MatchBot says 500hp at 6000rpm would require 377lb/hr of fuel flow, divided by 6 injectors is 62.9lb/hr/injector. At 85% DC that would be a 74lb injector. These are 90lb/hr so I should have some decent headroom.

[Laminar]

Survey says...yes there's headroom, but it's tiiiiight at the bottom. I'm basically sitting at the injector min effective pulsewidth and idle lambda is about 0.76. The fuel pump and min duty cycle can only get the fuel pressure down to about 160kpa (23psi) so I think I get what I get here.

Backing up real quick, I got the oil drains welded up and reinstalled. As a consequence of rotating the drain below the turbo, I can no longer access the bolts that holds the drain in place, which is a T47 torx with a fairly tall head. I ended up swapping that out for a button-head bolt that uses a 4mm hex so I can actually tighten it.



I went to install the other drain tube and as I torqued it up, the coolant fitting started leaking. I must have put just enough stress on that coolant line that it opened up. I pulled the fitting off the back and could see by the rust trail that my welds were not water tight.



I gave that another round of welding, giving me another change to practice TIG and also swearing.

When I bought the button-head screw, I actually grabbed a few different types of the same screw (M6x12mm), one of which was a flange-head bolt with an 8mm head. This coolant connection sits between the turbo and the engine block and there's not enough room to get even a standalone T47 bit in there, so I grabbed the flange-head and it went right in. I double-checked all of my turbo fittings and found that the inner passenger side coolant fitting had no retention bolt at all, it was held in purely by hopes, dreams, and the stiffness of the AN hose. With that done, I topped off the water and went for another start.



On the first startup, I was only seeing about 80kPa (11psi) of fuel pressure. Weird, but the Link accommodated and the engine ran fine. After a bit I pulled the fuel pump from the tank and found that the hose had burst right after the fuel pump, so most of the flow was bypassing the hose. I'm not sure this hose is submersion-rated . I cut off that last inch, reinstalled the hose, and we were back to normal.

I poked at the fuel and ignition tables a bit, but mostly I wanted to test boost control. Happy to say it works - at idle, the vacuum pump can easily open or close the wastegates via the boost control solenoid.

https://www.youtube.com/shorts/GSwWevC3TQ4

Startup is still 50/50, I posted a couple of trigger logs to the Link forums to see if we can nail that down. But when it starts, it settles down to idle very nicely. I fiddled with the oil pressure control a bit in hopes that it would spike to 90+psi when it doesn't need to, some small improvements there.

After I shut down I checked the oil drains and both are still seeping oil.



So another pull, leak check, and re-seal.

Other than that, the next step is to get the passenger side wastegate mounted up. The driver's side will have to wait until the engine is back in the car so I can make sure I'm clearing the steering shaft. I ordered an A/C compressor from Summit as the next time the engine is back in the car I'll need to mock that up and make a bracket. The Ford A/C unit is variable displacement and also exists within the Mazda framerail. This new one should be a bit more compact and fit where I need it to. I'll also need to pull the DI fuel pump off and make a blockoff plate for that, and make some preliminary clearance holes in the cowl to get everything to fit. I'm taking next week off of work, it would be super neato if I could get the engine running in the car, but we'll see how things go. 

[digitalsolo]

I feel your pain on the turbo drain oiling.    Turbo oiling has been my nemesis on my Mustang project.

Excited to see it all dialed in the car soon!

[Laminar]

Got my new A/C compressor, I went with the Sanden SD7B10 style from Summit. The factory Ford unit is variable displacement requiring an extra layer of control, plus the body size and hose outlets were in direct interference with the frame horn.







The stock unit was also going to cause issues with that turbo inlet, it was tight. I'll have to make up a new bracket for this one but it should clear the frame horn nicely and allow better routing of A/C hoses and turbo inlet hoses.

[Laminar]

Took last week off to make some progress on the Mazda. I wanted to get the engine work finished on the stand and get the engine back in the car. I started off by designing and printing a bracket for the new AC compressor.







Once I was happy with that, I made it out of 1/4" plate and got the compressor situated in place.







I used a laser and level to check the pulley alignment, I think it's pretty close.









I'll have to confirm frame clearance once the engine is back in the car. This was as tight as I could make the bracket while still leaving clearance for the hoses going into the top of the compressor and maintaining the factory serpentine belt and tensioner.

Next up is eliminating the DI fuel pump now that I know for sure the engine will run off of port injection only. I started trying to lop off the DI lobe with the sawzall but the hardened camshaft just stripped the blade’s teeth.



The angle grinder made short work of it.



I had to lathe out an aluminum plug for the oil feed and got working on a blockoff plate from some 3/8” aluminum.



Blockoff plug pounded in:



Plate fit up:



Hollowed out a cave for the end of the cam:



All installed: