RarestRX

Yo,


I don't think Mazda will offer a forced induction version of the Renesis. Why? Look at all the cars that have recently ceased production in Japan:

Supra (Turbo Inline 6)
RX-7 (Turbo Rotary)
Silvia (Turbo 4)
Skyline GT-R (Turbo Inline 6)

It seems like all the major Japanese manufacturers are moving away from turbos (Except Mitsubishi and Subaru). I've heard that it's because of new smog/polution regulations that Japan is going turbo-free.

I think Mazda is on the right track with the Renesis, get as much power as you can via normal aspiration. I drive a 1989 RX-7 GTUs which has been called "The Turbo II without the Turbo." I can rev the heck out of that thing all day with no worries about boost creep, detonation, boost spikes, fuel cut, etc...etc...

Most of the people I know who drive turbo rotaries are on their 2nd and 3rd motor. Forget that.

Kevin
1989 GTUs "The 787B was normally aspirated. I wonder why?"

SpreeGuy

not entirely, you can get a turbo in protege (ala mazdaspeed).

Skyline Maniac

Turbos are still around in Japan, for most brands. The next GT-R will be forced induced one way or another. The next gen Supra will probably also havd FI, unless they can manage over 100hp/L on a 3.5L engine.

As far as reliability of rotary engine, I don't really think people have that much faith in new technology. Only time will tell whether or not the Renesis will be a reliable engine. ROtary engines are tricky to work on, since only qualified mechanics and specialists would know what to do with them. This means there is a chance a know-nothin' mechanic might screw up somewhere down the line, and that Mazda can make a killing out of service fees because of supply and demand. We'll see though, Mazda claims great reliability with the Renesis - hell, Mazda claims a lot of things. I hope the rotary will be reliable though, because if not..... then who knows what will happen to the next RX7.

Hercules

When something goes wrong with a rotary... it's generally major.

Being that it only has 4 parts and something is broken... it's REALLY huge if one of those 4 isn't workin :p

But honestly... when's the last time an ENGINE died? It's generally something before that, like the tranny, electronics, etc... I think the same thing will happen here.

MrWigggles

The reason that turbos have been downplayed in Japan is that the Japanese automakers can reach the 277 Horsepower pseudo-legal limit with just a normally aspirated engine. They have no incentive to build complicated turbo charged engines if their simpler normally aspirated engines are making as much power as Japan's government allows.

Wether Mazda wants to admit to it or not I guarantee that 277HP was the design target of the Renesis they just fell a little short.

Personally, I think there will be a supercharger kit for this guy because it is simpler and gives the extra torque that the engine needs. High RPM is a non-issue IMO. Even High RPM VTEC Hondas can be supercharged effectively.



Although I'm not the biggest fan of Jackson Racing. They've had pretty good results with the VTEC's. The variable valve timing that kicks in just before 6000 RPM does give tuners fits, but the supercharger is still gaining horsepower all the way up to the 8500 RPM fuel cutt-off whereas the normally aspirated starts leveling of at 8000 RPM.

Jackson make a really nice kit for the Miata so they are willing to do Mazda cars as well. If Mazdaspeed doesn't come out with a kit, I would be willing to bet that someone does.

Also the problem with forced induction is going to be tapping into the complicated intake and exahaust manifolds. fortuneately a supercharger only has to tap into one of them. From an aftermarket standpoint that is a big plus.

-Mr. Wigggles

Maestro

The Rotors are being incresed in width by 10mm for the next gen RX-7. If the RX-8 comes out in the MPS version it will be this configaration that we will probabaly see.

3 Rotors weigh too much.

Supercharging ???? My question why ????

Turbocharging not at this stage with the Renesis.

However the MPS mazda6 is turbocharged due here late this year.

I would have to say turbocharging will be left for the RX-7 as simply. RX-7 owners love it :D

AbusiveWombat

Is this fact or fiction? Can someone point me to all this 4th gen RX-7 info? A lot of people here talk about it but I haven't read very much.

The power gained would more than make up for the weight gain and the torque would be much appriciated. Plus you don't have the stress of force induction...but as some have said the rotary holds up well with FI...I don't know cause I've never owned one. Just have heard the stories of the 3rd gen.

This engine doesn't need that much...just a little more torque across the revs. Supercharging makes a lot of sense. Look at the Jackson Racing superchargers for VTEC engines....a perfect solution for the RX-8. Small gain in torque across the revs (well not that small...around 40% gain). No need for fancy piping and intercoolers. Best of all...no turbo lag. If the RX-8 had around 300-320 hp we could be looking at a car that would run low 13s instead of mid 14s. Not to mention a 300hp RX-8 would mop the floors with most sports cars and hang with the exotics on any track. Also, the supercharger would add very little weight to the engine.


Turbos are nice but the RX-8 really doesn't need much more power. I mean an RX-8 with 400 horsepower would be down right scary. I don't think that this is something that Mazda would produce, I could be wrong though. Now a turbo is great for the EVO because the 2.0L four stock gets only ~140 horsepower....so you need huge boost to get it to 278hp. The turbo helps do this very efficiently but the RX-8 on the other hand starts with 250 hp...it doesn't need much more so it's more of a low boost application which I think falls more into the catagory of a supercharger. I think if you're going to go by way of forced induction the supercharger (similar design to Jackson Racing) is the clear winner. You get instant on power from start to end.

Plus I read somewhere here that the engineers at Mazda said that turbos were out of the picture but a supercharged version was in the works. The reason for no turbo was something with the emissions.

I think the most likely candidate is the supercharged RENESIS even though I would really like to see a 3 rotor. I understand why though. It's much cheaper for Mazda to throw a supercharger on then to add another rotor. As long as the engine is realiable with increased torque I'm happy.

wakeech

trust me, this is fairly privy info.
i know others who have said the same. the 4th gen is gonna get a higher displacement bi-rotor.

the biggest problem with a 3 rotor is cost, and secondarilly weight for the application: Mazda doesn't have a market for a +375hp motor... and don't kid yourself, a 3 rotor could top 400. they dont' need that kind of power, or size.
the larger displacement bi-rotor would be much cheaper to develop, produce, and employ, while still making the kind of power demanded by the market.

if someone says "the RENESIS needs more torque" again i'm gonna scream. if you really think about it, and look at how far this motor has come from the last all motor wankel design from Mazda (the Series 5 13B found in 1989-1991 RX-7's), it's world wonder number eight.
supercharging may be an answer for some, but i've raised my concerns about it in other threads. i encourage you to search on it.

MrWigggles

I don't care about want happens for the RX-7 for 2006. 3 rotors, bigger rotors, etc.

I care about what will be done to increase the RX-8 to the 300+ HP level where it belongs.

-Mr. Wigggles

CraziFuzzy

The RENESIS needs more torque... :D :D :D :D

Actually, it doesn't, but it would just be nice for passing on the highway, I mean, I have no problem dropping a gear or two, but it would just be nice if it had the response to NOT need to drop it all the time, y'know? I don't think there is much more that needs to be done to the 8, and the only thing I can think of is the need for some psi in there at the low revs, hence all the research I've been doing. I figure that there will be plenty of companies (Jackson for one) that are going to make some supercharger kits, probably some big ones, I'm thinking I'd be happy with a simple small non-intercooled SC, just or drivability, I'm probably not racing the car until I've had it for about 5 years, and I've bought a new four-door for the kids. Then I'll be putting a large, intercooled SC in it, with some serious exhaust and maybe some porting to take it on the track and just have some fun. But as long as its a daily driver, I'm gonna try to keep that simplicity that is so great about the rotary. I figure adding 2 more moving parts isn't too bad.

rotary crazy

Hi, everibody it is my first time so here it goes:

I belive mazda is a company nown for leading edge developments and the new RX-7 should be no exeption, I will not be satisfied wiht one of the bunch sports car I belive mazdas personale feels the same way.

mazda has never taken the easy way out and I belive they will not wiht the RX-7 and RX-8.

In my opinion mazda should offer a complete line of engines( as does audi ) for the RX-7,RX-8 and new miata:

2.3 inline 4 (the one in the mazda6 for the miata)
3.0 v6 (the one in the mazda6 also)
1.3 renesis 250 hp ( I do belive the miata should have this opcion as well as the new RX-7).
1.3 FI sc or tc renesis 300hp to 320hp
2.0 tree rotor renesis 370hp to 400hp ( I think making a biger engine 1.4 or 1.5 renesis cant be cost efective if it is why dit mazda make a three rotor in the first place for the eunos cosmo?).


FI is no problem my 1994 fd is in the 90,000km( 56,250 miles) mark and runing 14.5 psi, but mi cpu was done by petit racing and i have hat no problen wiht the engine , and my 1989 turbo fc have now 62,892 miles I am runing 10psi boost, I did replace that egine a couple of times wen I put more boost into it and dit not upgrade the fuel system.

Maestro

No No No !!!!!!

RX - Stands for Rotary eXperiment (Don't ever put a primitive piston boinger in a RX)

Also in regard to the 3 rotor being too expesive to build. The cosmo was only built for 1.5 years with the actual top spec only for 1 year. reson : Not cost effective.

The renesis might be more cost effeffctive but I would say the only motor we will see possbily in the RX-8 / RX-7 will be the new larger diplacement 2rotor.

santino

i completely agree with Maestro. No pistons in any RX series cars.

it was too bad for the Cosmo. it was supposed to be a great car; it had great power, looks, and a fine interior.

rotary crazy

sorry I was not thinking, the piston engines for the miata(only the miata not the rx-7/rx-8) I think there should be a rotary miata opcion also (mx-5 RE).

I think the cosmo was so expensive because it was a limited produccion car and never intended to be produce in large numbers, also remember the cosmo was twin turbo, a NA 3 rotor should be far les expensive ( I belive that is why the rx-8 is les expensive than the last RX-7).


Just think 370hp to 400hp NA 3 rotor renesis on a 2,600 to 2,800 pound RX-7 then put a SC/TC on it !!!!! oh my god !!!!!!.

Maestro

Read between the lines ;D

Also there has been talk about a RE powered MX-5/Miata.

Model isn't due for a update for a while yet but a RE N/A option would definately make a great little sports ragtop.

maxcooper

One option would be for Mazda to develop higher-power (larger displacement) RENESIS engines and leave forced induction to the aftermarket.

However, I worry that the FI efforts would be limited by high compression on the factory engines. If Mazda did some FI version themselves, we would have a very good base for boosted performance.

A 3-rotor RENESIS would be nice. 3-rotors sound fantastic and have a lot of torque. But they are a lot heavier and it might be a challenge with the side ports (middle rotor would have two shared exhaust ports). I doubt we will see this. A larger-displacement 2-rotor RENESIS for the Mazdaspeed RX-8 and a turbo version offered in a high performance version of the RX-7 would be great.

In the choice between a turbo and a supercharger, I'll take the turbo. Boost control, mounting flexibility, efficiency, no mechanical drive connection to high RPM engine, etc. all come to mind as reasons for the choice. And I'm a turbo guy, so I'm probably a bit biased.

-Max
365+ RWHP / 300+ RWTQ (last dyno @ 12.5 psi) single turbo FD

MrWigggles

Yeah, on pump gas with the 10:1 compression ratio of the RX-8 you are going to be limited to about 5 up to maybe 7 PSI before having to intercool an Eaton supercharger. That will equate to about 40% more power which may or may not be enough for some people.

It would be enough for me but others might not be satisfied. (It definitely won't make 365 RWHP :D)

-Mr. Wigggles