wankel rotary renisis 13b 230bhp standard uk spec.


New member
northern ireland
mazda Rx-8 Hi-Po
evenin lads, need some help on this one .

iv a 230bhp rx8 she's running well havnt had a bother with her the only thing iv found is that she is starting to sound as if the c.a.t is blocking thurs no e.m.l light and no stored dtc's cant fault it electronically . shes front end noisey on throttle almost as if the airbox was off but not as severe i,v checked all round that area and cant find faults ,,

i work for citroen/mazda and a have an old blocked c.a.t in work if i removed the blocked c,a,t material and made it into a straight through and fitted it (temporarily) would it be worth it ? or would it jus throw the eml light on and kill her on back pressure ?? im not sure if they benifit from back pressure w4nkels are hard to grasp in certain areas .
HELP !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! :)
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The lambda sensor is likely to play up. I'm pretty sure that JDM spec RX8's do not have cats anyway though, it was to meet the euro emissions requirements. Do you have an air leak on the intake? It could manifest itself as a split that closes up completely when not under pressure.
thanks for the quik reply mate,

they defo do have a c.a.t thier 1200 +vat to replace, if i plugged the sensor in and let it breath fresh air it should keep the light off ?? but i think im jus being fussy but as a fellow driver/mechanic you just know when something doesnt feel normal ? im at a loose end i havnt spent too much time on it but i think im guna have to do a we diagnostic and try and piece it together
The sensor is sniffing for oxygen so if it waas left breathing fresh air it would assume the fuel is lean and trim it back. I would have thought a remap would remove the catalyst from the calculations. The RX8 engines run very rich to start with to warm the cat up so nort sure how it would respond to cat removal.

Did you realise that the car would not pass an MOT emissions test without a catalyst and as such it would be illegal to use on the roads?

It doesn't sound like the cat to me though. The best mod on the wankel engines are porting, the standard ports are a bottleneck.

You'll be interested in this video http://video.google.com/videoplay?docid=5371694855581557376 at 2:25 it sounds quite nice when he revs it.
thanks for the reply wayne its a hard one to call . she is due m.o.t next month im fully aware of the mot requirments it is completly experimental lol im a qualified tech for citroen and mazda i enjoy fiddling with any car but this engine is taboo when it comes to mod's nothings set in stone , you seem well versed with motors wayne would the porting run me big money ? i know a standard cylinder head is easy to get ported and polished but would it be an engine out job to have exhaust/inlet ported on the engine side ? i think a re-map is in order once mot passes :) but fuel economy is a worrying problem as i use this vehicle to and from work etc. thanks again T.J Agnew
Not sure there is much you can do to improve fuel economy. They have a big drink problem, it is a shame because they have great handling and a super smooth power delivery.

I don't know how much the porting will run at and guess it varies a lot from tuner to tuner. These engines seem to be a "Big mystery" when it comes to tuning. I suppose the normal rules cease to apply. Nitrous injection should be relatively straightforward to do though.
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