Yo!

[Mr-miata]

What's up guys!

Thought I'd sign up to the forum to learn a little more about the 13b and hopefully figure out a way to get mine running just the way I'd like!

I actually drive a rocket bunny kitted 89 Mazda mx5 (Eunos roadster) After getting fed up of the poor performance of my stock 1.6. I've decided I'm going to swap the engine and gearbox from a (231) rx8.

I have bought a Rx8 for parts and I collect it tomorrow. Being an idiot I've bought the 4port 5speed without realising.. is this still a good engine or should I keep looking for a 6 port?

I plan to move away from the stock efi and use a Weber 48ida downdraft carburettor. Also looking to use Msd ignition but not sure how to hook it up to the Renesis as doesn't allow for a distributor?? Correct me if I'm wrong. All help greatly appreciated!

Thanks Dan

[GreySilver Beast]

Hi Dan & to the RX-8OC


Please check out the EVENTS SECTION's for anything coming up soon in your area

[Shagrington]

Hi and Mr-miata. I'll leave the answers to your questions to those among us who know more and are far more capable than I am. The sum of my own knowledge is based entirely on what I've read here.

[Honkytonk]

Welcome Mr-Miata, I think you're in the right place.

First off, without wanting to quash your enthusiasm, there will be those who doubt you'll get the swap done - there's been loads of comes and goes with engine swapping round these parts, and we rarely see finished product around here. That being said, I really don't want to quash your enthusiasm, because I'm definitely looking forward to seeing it complete. We in fact have a current member who's done an excellent 231 into MX5 NC conversion...

PAUL! GET YOUR ASS IN HERE!

For your question about engine, I think the general consensus is that for driving about, the 192 and 231 are roughly the same and there is surprisingly little to pick between them, partly because of the longer gearing in the 5 speed. Certainly I think they share a propensity for over promising in the power stakes (most 231's put out about 200 from the factory, about 180-190 in good nick now, whilst most 192's about 180/170-160). However, I think that's more than enough power for a eunos, and whilst you may lose out over one of the V6 or turbo conversions available in 'pub' numbers, you win in linear power curves, smoothness of delivery, and general awesomeness of sounding like a jet as you hurl those rotors past 8k revs. And it'll be a bit different!

So I wouldn't worry about the engine being 'The wrong one'- they're all 13b's and that's the important bit. If you sign up as a full member you get access to the full Mazda technical documents on both engines, which include all the differences you'll be worried about between the 192/23, as well as loads of help from everyone on here much more knowledgable than myself. And it'll also allow you to sell stuff on the forum, which, if you've got a whole car to get rid of, could be very helpful, and allow you access to the group buys that happen pretty regularly around here, which will often pay for the price of membership on their own.

So I'll say welcome again, and hand off to someone else who'll probably be more mechanically helpful...

[mi60o0]

I know julien jdm import put just over 160 at the wheels 192
Mine is 165 wheels to standart original engine
Isn't a big difference 192 and 231

[Paul_13]

We in fact have a current member who's done an excellent 231 into MX5 NC conversion...

PAUL! GET YOUR ASS IN HERE!

Here

[Paul_13]

The mx5 NC and mx5 NA are two completely different bases.

I think you'll be creating a lot more work for yourself using a carburettor and aftermarket engine management, there's a lot of things to get wrong when tuning. Rotaries aren't as forgiving when running lean or knocking. Not to say it isn't achievable, just will take a lot more work.

I personally would transplant the following
Rx8 engine
Rx8 gearbox (you'll have to make the PPF fit. I've no idea if this will work. Or modify the rx8 ppf. Chop a section out and reweld it)
Rx8 engine loom and ecu
Rx8 fuel pump wiring
Rx8 clocks (you will need these CANBUS etc)
Rx8 immobiliser etc

The engine management system is pretty much stand alone compared to the rest of the car. You can isolate the 'engine bay' side of things and work out what to do with the interior electrics.

The bits in not sure of
Propshaft
Fuel pump (although these look like a standard 65mm fuel pump. A 340LPH pump should be a direct fit.)
Engine mounts (shouldn't be too hard)

I would personally go with 231 engine. I also made the mistake of buying a 192...luckily managed to cancel it.

[Mr-miata]

Thanks for the info guys, I'll definitely take on board everything that's suggested! sorry I've not replied sooner but it seems getting the engine out of the rx8 is more difficult than I first thought..

There's so much crap under the bonnet. It's nothing like an mx5, that's more like playing wiyh Lego compared to this. The amount of wiring and sensors etc on a rx8 is unbelievable, I soon got frustrated and cut away all the loom leaving just the connectors intact with a little but of cable. Just couldn't help myself. Maybe that will make things more difficult in the long run but it definitely made today easier!

I have to say this particular example is definitely what I'd call a rat rod. Upon getting under the car i spotted holes in the floor pan, I could see the soundproofing inside the car from underneath. Not only that I was able to pull the bumpers off by hand and the same with the structural skirts/sill the whole car just crumbles in your fingertips. Jacking this car was a nightmare haha. For a 2004 plate I expected better Mazda! Never mind that though as I planned to have it crushed soon anyway.

Luckily for me the interior is immaculate so I may make something back on that but more importantly the engine is spotless too.

It's still in the car atm but I finally have all the crap out the way so it should be on the bench in the workshop tomorrow. The engine unfortunately is a 192 but for now I'm gonna keep going. I mean I was told it had a rebuild at 75k now, 89k and there definitely signs of this. The engine is clean compared to the rest of the car. The oil, the coolant and all other fluids are crystal clear, it has a recent uprated starter motor and coilpacks. The plugs and HT leads also looked new as well as all other service items. It also started 1st time everytime hot or cold, there were no awful noises or misfires
Just a thought, theInjectors are green and red, are these items stock? Maybe a quick search is in order..

I'm thinking if i remove the engine from the gear box it will be easier to get out but does anyone think it's better to drop the subframe out and remove both together? I mean it will have a new clutch and be rebuilt with a bridge port before it goes in the 5 so I dont mind either way. Just want the quick way as the cars currently taking up space in a friends garden haha .

Will talk more and reply to everyone's comments personally in the morning but I really need some sleep. Pleased to see this thread has gained some interest too, I just hope I can deliver

Thanks

[Lemon]

don't knock the 192 engine, whilst it may be the "low power" version it does have more mid range torque and when i tracked my old rex was more than capable of keeping up.

besides, unlike the 231 people have actually seen serious gains from porting 192's (there was someone tracking a ported 192 at the agm meet in February which was a rocket). plus they seem to be happier when it comes to winding boost into them.

all in all welcome to the OC, just make sure you document your swap

[Honkytonk]

General consensus is there's really not that much in it between the 192 and 231 - the 192 being essentially in a state of detune is, as lemon says, helpful for goading more power out of it, and the characteristics of the engines balance each other out.

[ChrisHolmes]

Join fully so you can access all the technical FAQs and manual. Get yourself an engine loom from BigPete as you will need this to connect everything up.
Stick with the original fuel injection system and ECU as changing to the 48 IDA will I reckon just bring a load of pain and additional costs to the project.