Since the Renesis has such power NA, would it be possible to swap into a second gen, or will it be as difficult as a REW engine?? Thanks, just wondering...

 

as tough as the rew. similar mounts that dont match the FC locations and you have to use a stand-alone ems and modify the engine for use by the standalone since the renesis ecu wont work outside of the rx-8 (throttle by wire, wheel speed sensor ect.).

if you want n/a power you are better off building up an s5 motor. with a good port and tuning they will make as much power as the renesis for a lot less money.

 

A key thing you MUST learn is to search. This has been discussed at length. Honestly the simple answer imho is don't bother. You'd spend 10k dollars for 240bhp. You could be in the 400whp level for that kind of money.

 

agreed..... if your going to go through the trouble and money of doing a swap like that, it would be more beneficial to swap a 13b-rew (more power, more torque)(but that swap is still more $$ than its worth).... but being cost effective, just swap a 13b-re and w/ the $$$$ you save, mod the crap out of it! ive heard that a 13b-re swap is not very difficult to do....


that was in regards to swapping motors.... i personally do think swapping motors is "cost effective" at all......

 

Do you have the engine, engine harness, stock RX-8 ECU, and RX-8 FSM in hand?
If not, do you know how much all of that costs?
I've never seen an RX-8 for sale, but I do come across "rare" engines like 20B's (~$3,500) and 2JZ-GTE's (~$3,000) no problem on eBay.
This makes the RX-8 a bit of a rarity.


-Ted

 

well actually you could probably use a mega squirt for the ECU... but finding the engine, making the mounts and everything else would make the engine worth more than twice the price of the car.

 

Yep, megasquirt was recently used on an rx8 for the first time, it was pretty interesting for them to get it to control everything needed on the rx8, though.

 

Do you have a link on that???

 

I think a jet engine would be much cooler in a second gen anyhow. Does anyone know where I can get some custom motor mounts for that...:-)

Brian

 

Original thread http://www.rx8club.com/showthread.php?t=65388

Post 161, page 11 is where rotarygod finally posts that it has been completed and is running http://www.rx8club.com/showpost.php?...&postcount=161

 

You could, but I'm willing to bet that the result will be far inferior to the stock ECU. As we know, the stock ECU runs the 6 injectors, actuators in the intake passages, etc. etc. The Megasquirt's resolution is FAR LOWER then most of the other EMS systems. I'm not saying that it's a bad ECU, but I really wonder how well it will work on an engine that is as.....optimized...as the Renesis.

(I have nothing against the Megasquirt. I've installed a bunch of them on piston cars with great results. But in this application I have to wonder...)

 

I think one of the main reasons the megasquirt is so good on fc's is that the ecu is 15+years old and uses an outdated method of measuring air flow (AFM). I don't know how the renisis' system works, but I bet it works much better.

 

There's nothing wrong with the AFM. In fact, it makes a very robust system that is easy to mod and hard to blow up. Speed density systems (ie. Microtech, Megasquirt, Haltech, etc.) all measure load via manifold pressure. If you suddenly increase airflow, the ECU does not know this and the engine will run lean. You then need to retune all the fuel maps. Since the AFM directly measures areflow, the ECU is able to compensate for increases (to a point).

 

If you're curious, read that thread I linked to with rotarygod's results on the MS for the rx8. He actually found the idle, so far, to be better once tuned than the stock PCM.

I don't know how much you know about the rx8 and its PCM/tuning, but honestly most rx8 owners on rx8club that are trying to modify their car are NOT happy with it. The stock PCM is wayyyy too unforgiving for things. Every mod that is done that alters anything results in the PCM retuning/relearning the mod and trying to revert it back to stock, or close to, levels. This results in pretty pathetic gains from many mods. Also, the longer you go with the tune the more the PCM learns and continuously recalibrates itself, this results in loss of power over time. Many people have found it beneficial to erase the current tune on the PCM about every month or two to start over with a fresh tune, and go from there. This allows the PCM to stay somewhat manageable with the mods and less loss in power so long as you keep clearing it every so often.

Mazda went all out on the monitoring system for the rx8, it's rather sad actually. With aftermarket piggybacks and Mazsport's new drop in replacement ECU, people are finding tremendously higher gains, while still controlling all the stock parts and emissions components normally, than the stock PCM allows in both FI and n/a situations.

I think the MS is probably a big step in the right direction for modifying rx8's, but that's not really pertinent here since this is a 2nd gen forum, and I've rambled on too much

 

When I get some time, I will read the whole thread. Honestly, getting and idle is not exactly rocket science. I don't consider that to be much of an accomplishment.

My main point of curiosity is concerned with what will happen to all the magic in the stock manifold. Do all the valve controlled ports still function? What about the fuel injectors since they are now firing in batch? These questions are likely answered in that thread...I guess if the 'Squirt is installed totally independently of the stock ECU/ECM, then all these stock functions (minus the injectors of course) are unaffected.

But I am going to come clean and say that I don't know a hell of a lot about the RX-8 past what I've already posted. Like most new cars, it doesn't do anything for me (one test drive was enough to confirm that).

 

the MS is been used by rotarygod to gain complete control over the injectors but he left the stock ecu control everything else. He can fine tune the car's afr's now but the magic in the manifold is left to the stock ecu. He said it can be made so that the ms controls all of this but there's no need.

He's still working on getting the ignition timing part to work because the ignition on the rx-8 is independent for all plugs (no waste spark) and also it runs negative split at idle.

 

ok, no, i don't have any of the pieces. I was just wondering, not that it should be done. The appeal was that it had more power NA, stock than the T-II.

PS- I already have a T-II, please don't flame my curiousity, thanx

 

Bottom line...it's not worth it.
A J-spec 13BT costs less to get up and running.
I'm estimating a minimum of $5,000 to get the engine and have it up and running...even with an MS.
For $5,000 you can get a pretty stout 13BT set-up with an aftermarket turbo producing 300hp+!


-Ted

 

^don't forget the nice ported rebuild with that, my 13bt+tranny only ran $650, alot cheaper than a renesis.

 

yeah I did see a reni sell on ebay last month for $4500 with no ECU and a cut harness