RX10000RPM

I'm about to begain the process of seriously moding my 8, but I keep haveing the this re-occuring thought that keeps poping up in my mind. I love the RX-8's body & handling but from I modifying stand point the older RX-7 13-B Rew is the way to go. Do to fact my 8 is NOT my daily driver this gives me the flexibility to pretty much do any crazy thing I want :D . I'm not trying to rag on the Renesis it's a great engine, it's just a little tricky to git big power #'s from. The 13-B on the other hand seems to be a better choice for what I'm trying to accomplish that being around 400HP.

The question now is, just how hard would it be to switch the Renesis for a later model Turbo 13-B engine and what would the consequences be . I have done a search and can find nothing on this ever being attempted , minus a 20B swop I've seen. I'm thanking - fully ported 13-B Rew, Custom Turbo setup/ Stand alone engine management & a stronger tranny that can take the extra power. How ever I'm concerned about the smaller details like - wiring, will I be able to hook up the A/C (I live in Texas it's always summer here ), will I be able to use my stock gauges........ I'm not looking for all the answers just some pointers that can get me heading in the right direction any help would be great .

Moostafa29

400hp is the goal eh? Guess you haven't been following the PTP thread, or that search button stopped working all the sudden.

rotarygod

The 13B is a step backwards. It's a less advanced engine. Take the turbos off of it and it's pathetic compared to the Renesis. The key is in tuning. You can tune a Renesis now with the recent ecu options out there. You can get 400 out of a Renesis. Too many people currently care about their cars though as most are daily drivers and most want to keep their warranties. Just get a good turbo on it and tune it right. That'll save you the effort of adapting another engine, motor mounts, etc into the car and the figuring out how to get another ecu to control it. That'll be more expensive and more work in the end. You'll lose all of the nice features of the car going this route too. Why not have a car that still has everything it came with but is just faster? That makes far more sense. Swapping from a Renesis to a 13B is like swapping from an LS7 engine to an older antiquated small block Chevy. It makes no sense.

RX10000RPM

Wow, I had now idea the Renesis was that much better than the 13-B. I gess the reason I was questioning a 13-B swap was due to the fact I've seen hundreds of RX-7's making 400,500 & even 700hp but have yet to see an RX-8 break into the 300's. As for the PTP guys I believe I did read that they had come close to 400hp, but I never saw the dyno sheet & as you now from beeing on this web board....... Talk is cheap with out proof .

brillo

well the dyno sheet is up there now, and they hit some sick numbers.

The main Renesis tuning issue has always been getting engine management working that is reliable and accurate. Ok, I suppose you could argue the compression ratio is a little high, but in reality, you can still hit your 400 number with a 10:1, you just have to adjust timing.

why go to all the trouble to swap the engine when you've got several ECU options (HKS, Mazsport, and Motec) and several turbo options. Hell PTP will sell you the manifold standalone if you want to do a custom unit.

LittleJohn

Patience is of the virtue..
You must rememer the that the latest gen 13B has been arounf for ages.....
The Renesis on the other hand is first Gen.. IMO Mazda is playing it safe by locking everything down so that aftermarket tuners can't do *****. They are trying to avoid he RX7 debacle with the rep of over heating and thus inreliable.. etc etc..
I reckon a few more years and the Renisis wil be at least if not more powerful than the 13B could ever be..
Just my 2 cents worth though.

gh0st

the renesis will not surpass the 13b-rew in terms of raw top end power

denward

MadDog

^ great post. I like all the facts you used to backup your statement...

gh0st

i guess anything is possible, but its highly unlikely. the subject of why the renesis will not make be able to top out as high as the 13b-rew has been covered GOD knows how many times.

that doesnt mean the renesis isnt superior, it just means max hp isnt what it was deigned for. 10 years down the road.. who knows...

denward

Luftwaffle

Links to threads, please.

therm8

yes please...links...

gh0st

not sure if there are any threads directly addressing that topic but do a search on 10:1 or compression. i think the last time it was addressed was a few days ago in the tread "the limit for the 8" i think by RG. he states in one of his posts that the renesis is can be a very powerful engine and it is very possible to reach NEARLY as much hp as the 13b-rew. ill find more posts by reputable sources if youd like. i get off at 5 :P

denward

Ajax

I think it's a little early to make such a statement. PTP has a dyno sheet up at 365 and it's not even fully tuned and that's running 13.2psi on a GT35R. The power is there. It's time that we need. We're dealing with a much more complicated engine management system than the previous rotaries. We're dealing with a major deviation from the exhaust ports of the previous rotaries. There's so much in this engine that is new and technically more advanced that it's going to take a while before you see numbers as high as you've seen in the previous generation RX7s and it's gonna cost a lot more for a while.

365 at the wheels is pretty good if you ask me. I'm sure the japanese tuners are pulling bigger numbers than that and the guys in PR have already posted 394 at 18.9 PSI and are now going back to port the motor.

I'd say if you wanted to do a motor swap that was worthwhile, put a 20B in the car and spend some real money. Otherwise, i'd say time is what the renesis needs and the power will come.

ranger4277

As much as RG knows.. not even he can be expected to KNOW the limit. Guessing is all anybody can do until the time and pain goes into proving it one way or the other. It is foolish to even attempt to declare what this engine is and isn't capable of at this early stage in its life.

Fortunately we have guys like Eightman1977 to push this limit as we all sit back and enjoy the show. If it doesn't meet the high end power of the 13B REW that is fine, it is still amazing that Mazda improved the NA rotary so much. (even more amazing that they actually brought the rotary back)


Slightly off topic: Why is it we never hear crap about the Japenese tuners and their progress?

Dragonrider

Your opinion is noted, interesting that you provide no factual basis for it.

RG has been there, done that, and is offering sound suggestions based on actual application, what is yours based on.

If you have a fact or two to share great, otherwise your factually baseless opinion is duly note and should be filed with all the other household rubbish.

gh0st

i agree 100%. there is no way of knowing what the limit is and as i later stated, anything is possible but it is still unlikley. the renesis wasnt designed to be an fi motor and as a result it wont take to fi as well as the 13b-rew. there is only so much timming and tunning you can do before seriouse modifications are need to extract anything else from the motor.

denward

gh0st

uh... my information is based on reputable sources (i.e. RG, the guys at pr who also experienced problems with the compression ratio). i dont recall saying i have any in depth rotary FI experience. can you point out were i said i did?

this info didnt come from me, hence the reference to other people. im sorry you cant understand that concept. your post have no application to this situation. its not like im claiming something new. its been discussed by the people that have earned all our respect on this forum. you dont like it? take it up with them.

FACT:
the renesis wasnt intended to be an FI motor. it was designed for max performance as an NA motor and as a result, FI performance IS (in stock form) compramised when compared to the 13b-rew. it is still uncertain weather or not these propblems can be overcome.

FACT:
the 13b-rew was intended for FI and it sets the bar around 700-800 hp with "reasonable" (subjective) modifications.

then in the other hand

FACT:
anything is possible with enouph money.

i dont need to be RG to know this. these are facts not opinions or suggestions. i dont need to have been there or done that for these things to be true. all in all.. i stick to my guns. ODDS ARE the renesis will not match the 13b-rew in terms of max hp out put. (dollar per dollar of course taken into consideration) provide me facts that suggest differently if you can.

denward

LittleJohn

Dude... unless you are part of the inner sanctum within Mazda.. the above "FACTS" are really only assumptions. Irrespstecive of where or who they came from.
Yes the renisis does have somewhat high compression .. but who's to say that won't be reduced in the second Gen Renesis?? (an assumption on my behalf )
Like I said b4 Mazda is being cautious this time round.. Plus in a few years time, the Renesis will be running on a different type of fuel.. Who knows what, but with oils prices skyrocketing like they are now.. I doubt that anyone will be using petrol like they are now..

RX8PDX

Doesnt the REW have lower compression than the Renesis? Are there lower compression parts available for the Renesis?

Is anything strengthened in the REW compared to the Renesis?

gh0st

ok... this is going no were quick. how on earth are you going to sit there and say that it is only an "assumption" that mazda designed the 13b-rew with intent to go FI??!
what, did mazda design the FD rx7 as a NA car and the turbo ferries came and attached not one but two turbos to all the FDs when no one was looking.... RIIIIGHT... (if so i wish they'd come give me a visit :p )
*sigh*it is not an assumption that the renesis wasnt designed for FI. it is certainly not an assumption 13b-rew was designed for FI. and i am a firm believer that with enough money, anything is possible. <--- ok, thats not really a fact but i think you guys get my drift.

rx8pdx

yes the 8 has higher compression and i have heard of low compression rotors for it but thats about it. no pics, #'s or anything.

denward

LittleJohn

Mate,
maybe I'm not articulating myself very well...
I guess the long and the short of what I'm trying to get at here, is that when the 13B first appeared in 1975?? I think.., it was was NA only after several generations did Mazda slap on a couple of turbos (1983).
Similarly, the Renesis is a first Gen engine.. give it a few more years and I'm sure Mazda will slap a turbo or two on this baby as well..

Even though we aren't seeing huge amounts of power from the Renesis.. I think this has more to do with engine management than with the ability of the engine itself. With comp ratios of 10:1, I would be hard to run with the same amounts of boost as a 13b-rew, but that's not to say that the same or greater power can't be had on less boost.
Hey.. then again I could be talking out of my ***.. all I'm saying is give the tuners some more time and I'm sure affordable big powered solutions will come to fruitition

Jon

I think this is definately a valid discussion but I do think patience will be the key, eventually someone will discover the power potential of Renesis Motor. I dont believe anyone can say that the Renesis will or will not make as much power as a rew. I can tell you from what I have seen that it definately has the potential but I haven't seen the limit yet or even how long it will last at any given power output. But I think we will just have to wait a little while, for some brave fool to attempt the impossible. There was a time when we thought Supras would only make about 500hp on stock motor.... and boy was everyone wrong. Its all about testing and research and that will take time. And many blown motors before someone discovers the power limits.

Just my .02 cents

Jon

Dragonrider

You still don't quite get it do you.

All your so called facts are nothing but personal opinion based on smoke and mirrors. While I will stand for your right to voice your opinion, passing your opinion off as a fact is nothing but frivolous nonsense.


In reality, I now see that you would not know the difference between a fact and an opinion if it had teeth and reached up and bit you.



When asked for the facts, all you do is validate your personal opinion with opinion. 0+0=0

Red Devil

I think a very clear fact is that the Renesis is much more technologically advanced than the REW. NA vs. NA, it handily outpowers a 13B - http://www.rx7.com/techarticles_rx8power.html - based on this, and Mazda's history with the rotary, we can make an educated guess that a OEM Renesis will or does already have more power potential than a OEM REW or any other older 13B platform.

Above is basically what Little John, RG and others have already said, I just tried to make it concise.

gh0st

littlejohn,
thank you for clarifying and i see what you are getting at here. more or less i would agree to a certain point. but we arent talking about weather or not the renesis will eventually go FI, mazda mostlikely will if they ever want to compete with nissan.

this whole fiasco started when i disagreed with you on your post saying that the renesis will one day be more powerful then the fd motor. however, i didnt provide reasoning so it aggravated a lot of members here. i later then explained myself. like were i got my info from and well known facts about the renesis that supported my initial comment. i think the renesis is a better motor then the 13b-rew. i just dont think they can match the power. the only way it can would be through FI and problems arise not only in compression but in mechanical terms as well. look how the ports are laid out in the motor. unless there is a way to get the ports to flow an insane amount without making them bigger (which there really isnt any room), youve got a mojor choke point if you are using a large snail. some of the things that make a renesis a renesis just get in the way of FI when we are talking about extreme hp. granted i dont have experience with FI on a renesis (i will after ptp is proven to be motor safe) and i may be completely wrong but i can only speak of the things ive seen and know to be true. im rooting for the 8(i own one for crying out loud). but if i was a betting man and the bet was max hp without major alterations to the motor, my moneys on the fd motor.

denward