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Rotrex vs EFR: 1 year to decide

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Old Oct 2, 2019 | 02:43 PM
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Default Rotrex vs EFR: 1 year to decide. 1 week later buys a K swap

Finally took the plunge and picked up the parts I will need for boost.
Car is a red 2003 sport package, 50k miles and undercoated every year. (IE, absolutely filthy but free of rust.)






Last year all of that got installed, car has been pretty fun and reliable on track but it definitely needs more power at this point. The build path I'm on should be valid for my original goal of a c30-94 rotrex, or an EFR6258. I got to drive a 2560 turbo car a month ago on track and it was a lot of fun. The noise and power were great but it could only go for 5 laps before starting to overheat.
No plans currently to build my engine so I feel I won't be able to take full advantage of the extra power the EFR has to offer if I'm just limiting it.
Turbo would be faster on track but I like the simplicity of the rotrex. The most I've done mechanically on a car is change out brakes, this car is a fun way to learn and gain experience.

I have a year to decide what system to go with as I'll be spending 2020 learning the Megasquirt,and aiming at 2021 for boost.
I will hopefully be able to drive a rotrex car at some point to see if I even like it. If it's a well built rotrex and underwhelming then I'll be going turbo.



Got to spend some time doing front hubs after the originals decided they had enough and started making angry noises. Followed EO2K's thread and found that one of the inside bearings had zero grease, not good.





Also ordered a 949 clutch/flywheel, DW200 fuel pump, GM AIT, FF640 injectors, and a Wilwood prop valve.








And the piece that is worth more than my daily driver.





Picked up an AEM wideband as well, and some of these cheap o2 extenders.Same as the ones the big companies sell but for a fraction the price.










Decided to dive right into it and do the clutch/flywheel, not knowing if I would be able to get the thing back together in less than a few months. Final shot of the car before it went under.





Surprisingly it wasn't actually that difficult to remove the transmission. Spend the evening working on it and the new clutch and flywheel installed that night.






Replaced the clutch master, slave, and line as well while I was in there. The trouble started when trying to line the transmission back up. Even just getting it into position was not easy doing it solo. Next time I will remove more of the exhaust, thought one of the nuts was starting to strip so I left the downpipe on.
Had to call a buddy over to assist, after 20 minutes of wiggling it around it finally mated the bellhousing. Final step was to make the clutch pedal bypass switch and break the clutch in.







It picked up a consistent 3kmh on local road course main straight which surprised me. Car is a definitely more fun to drive with the light flywheel.


Did the prop valve next. Krown oil everywhere but the PPF bolts could be removed by hand on a Canadian car so it's worth it.





2 trackdays later and the rear exhaust bracket broke. Buddy welded it morning of the event.





Later found out that the resonator pipe had completely broken and was the cause of the muffler break due to excess movement. Buddy welded that back up and welded the wideband bung on as well. He also welded a new floor into my daily driver as mine had rusted through. What a lad.






Bought a new set of Hankook RS4s as well. They lasted around 500 laps of a 3km road course plus street mileage. No drop off in performance either until the outside rear at last trackday decided it didn't like existing anymore.














Since the car is a 2003 it has the Fuji diff, I had an 01 before this car and the difference between the 2 is noticeable. I got a great deal on swapping my diff for one he was selling plus cash. Waiting on new axle seals but I was able to get the car ready for it while I waited for exhaust to be fixed.







Dirty, but protected underneath.

Axles were being a pain to remove, had to remove the caliper and loosen the bottom control arm bolt to get enough clearance for the axles to slide free. I know people say they can remove them without touching the hub but even with the top spindle mount removed it didn't have enough room.









Hoping to get it all back together before the end of the week, do another track event, and then start installing the megasquirt, injectors, fuel pump, and wideband once they start salting the roads and the car goes away for the winter.

Bonus pic of telemetry app from my car and a friends turbo car. (Racechrono pro with an external GPS for faster refresh rates. The app has a predictive lap timer which is incredibly useful for coaching yourself while driving.)
His can do over 170kmh with a passenger before T1 while mine solo is at about 146. I am excited for boost in 2021.



Last edited by Bopop; Oct 23, 2019 at 07:50 PM.
Old Oct 2, 2019 | 02:52 PM
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EFR 6258 or 6758 if you want more than 300

Rotrex if you k swap
Old Oct 2, 2019 | 03:04 PM
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EFR! EFR! EFR!
Old Oct 2, 2019 | 04:09 PM
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K swap.
Old Oct 2, 2019 | 04:12 PM
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^ What this guy said. I mean this is miatakswap.net
Old Oct 2, 2019 | 05:14 PM
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I agree a K24 would be my favourite choice but the level of complexity of doing a TDR rotrex kit vs an engine swap is beyond what I'm comfortable doing at this point.
Eventually I would like the K with a rotrex and make the horsepower equal the license plate, but not at this stage.
Old Oct 2, 2019 | 05:45 PM
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then get the rotrex that you would run with the k24 so you have everything and just need the swap
Old Oct 3, 2019 | 01:50 AM
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Originally Posted by Bopop
I agree a K24 would be my favourite choice but the level of complexity of doing a TDR rotrex kit vs an engine swap is beyond what I'm comfortable doing at this point.
Eventually I would like the K with a rotrex and make the horsepower equal the license plate, but not at this stage.
You said you're not going to do that project for like another 1.5 years right? You'll likely feel better about it by then. I'd just keep it on the table. If you're not building the motor you'd likely be about in that same 200 to 220WHP range that a stock K24 can produce as well, and you'll have about the same amount of money invested for a complete swap kit and engine as you would going turbo or rotrex. Especially if you've got your stock engine and some parts to sell off during the process to help.
Old Oct 23, 2019 | 07:49 PM
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Originally Posted by Arca_ex
You said you're not going to do that project for like another 1.5 years right? You'll likely feel better about it by then. I'd just keep it on the table. If you're not building the motor you'd likely be about in that same 200 to 220WHP range that a stock K24 can produce as well, and you'll have about the same amount of money invested for a complete swap kit and engine as you would going turbo or rotrex. Especially if you've got your stock engine and some parts to sell off during the process to help.
That's essentially what I kept telling myself, eventually I want around 350-400whp and I'm not going to get that with the BP.

Right after finishing making this thread I saw the latest K24Z3 swap kit. After doing a few weeks of part searching and talking with the KMiata guys I went in for the Z3 kit.

Steep learning curve this year in relational to working on the car but it should be fun.


Also picked up a 2000 SE and hardtop for cheap. Going to use as an ironic winter drift missile and part out when it goes poof. Has about 70hp right now with a really weak spark so hoping a set of plugs and wires will sort it out.


I guess I have an MS3 and injectors available for sale if anyone is interested lol.
Old Oct 24, 2019 | 08:04 AM
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I’m doing a k24a2 swap on a 2000 SE right now. I’m hoping to start the motor this weekend. It’s really not too bad, just make sure you read the instructions a few times before you start and take it one step at a time. You’ll have no problem getting the swap done. Also, David from Kmiata is great and has answered all my questions in the process.
Old Oct 25, 2019 | 06:09 AM
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Another one joins the Z3 Mafia...
Old Nov 9, 2019 | 04:21 PM
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Originally Posted by Arca_ex
Another one joins the Z3 Mafia...
Yiss

Originally Posted by alienmiata1
I’m doing a k24a2 swap on a 2000 SE right now. I’m hoping to start the motor this weekend. It’s really not too bad, just make sure you read the instructions a few times before you start and take it one step at a time. You’ll have no problem getting the swap done. Also, David from Kmiata is great and has answered all my questions in the process.
Yeah they are great, been talking a lot with them and they're going to source an engine as it's half the price down there vs canada.


Figured out why the 2000 was running so poorly. Crank has a big wobble and the keyway is torn up. Going to do loctite fix and see if that makes the car driveable.


Old Nov 13, 2019 | 02:44 PM
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I had to do it on my 99. The key is clean everything, 660 in the keyway, and then slather everything that touches anything else with 243 (medium strength, oil resistant). I have done 5 cars this way with zero issues.
Old Nov 13, 2019 | 02:49 PM
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Originally Posted by x_25
I had to do it on my 99. The key is clean everything, 660 in the keyway, and then slather everything that touches anything else with 243 (medium strength, oil resistant). I have done 5 cars this way with zero issues.
Here's hoping. Was talking with loctite customer service rep about temperatures for application.
Coldest its been the last few days is -15 so I'm going to wait a week until it gets to about 3c and then leave the shop heater in engine bay for the night.

When you put the key back on do you slip on the timing cog first and then slide key in, or slide the cog over the key? I would prefer to do option 2 but I have concerns about the cog pushing the key too far back for the pulley boss to have any key left for it.
Old Nov 13, 2019 | 02:55 PM
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I put the key in then try and slip the cog over it, knock the key on the floor several times, wipe off and refill the 660, then put the cog on and key in.

Oh, forgot, I slather the whole crank nose in the 243 before putting the cog on.
Old Nov 13, 2019 | 02:58 PM
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Lol, that's exactly how I picture myself doing it.
I'll skid the dropping part as I really don't want to go hunting for it in the snow and grass.
Old Nov 13, 2019 | 07:58 PM
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Originally Posted by Bopop
Bonus pic of telemetry app from my car and a friends turbo car. (Racechrono pro with an external GPS for faster refresh rates. The app has a predictive lap timer which is incredibly useful for coaching yourself while driving.)
His can do over 170kmh with a passenger before T1 while mine solo is at about 146. I am excited for boost in 2021.
Very nice, 500 laps. I recognize TMP. How many visits to get in 500 laps?
I suck, as I managed to get out to TMP 0 times this year.
Old Nov 13, 2019 | 08:06 PM
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Originally Posted by oreo
Very nice, 500 laps. I recognize TMP. How many visits to get in 500 laps?
I suck, as I managed to get out to TMP 0 times this year.
I think it was 6 evening sessions this year. Generally about 80 laps or so each time in a 4 hour session
I really like the track, perfect for our cars as the speeds are low, plus the atmosphere is really laid back.

It does lead to some dumb stuff with inexperienced drivers in fast cars but for the most part on a Wednesday or Monday session it's pretty calm.


And yes, come hang out and drive fun cars.
Old Nov 23, 2019 | 04:20 PM
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Picked up the loctite and went to do the fix but I called the company first to make sure the temps were ok and they recommended it being above 15c. Waited until the warmest day in the forecast which was a high of 4c. Left an electric shop heater in front of the crank and let it preheat for a few hours and then left it overnight to ensure it would set correctly.

That was 4 days ago and I finally got it all back together today. Apart from a no start due to coils being swapped (oops) and actually running out of gas, it runs great.
All it needs is a new power steering belt and water pump/alternator belt and it'll be ready.



Picked up this as well, it runs fine but blew a brake line on way home and the alternator belt snapped so I had to use zip ties as a belt to keep the water pump turning. It wasn't charging the battery to begin with so I threw a good battery in the trunk with jumper cables to limp it home the last 2 miles.
Clutch is also very weak. It can hold power but if you slip it at all the revs just stay where they are.
If I have the time and motivation to fix the brake line and do a new battery I might use it to let buddies do tandem drifting this winter with the purple one. If not, it was super cheap and came with a hardtop so I'll just part it out.



In terms of the K24 project. I'm going to wait until the full guide is released so I know exactly what parts to buy. They said they're releasing a custom wiring harness as well for this swap so depending on price I'll go for that instead fiddling with an unknown used one.
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