After almost a year since the release of the RX8, I come to the conclusion that Mazda knew that adding a Turbo to the renesis was going to be hard on the engine causing problems to the structure/function aspect of the engine and decided no to add it. I believe that aftermarket will be able to make a Turbo system for the RX8, but either is going to be tough on the engine and thus reducing the life or it will completely blow up the engine. I think that the engine as it ,is already max out to perform without risking engine lifespan. Maybe Mazda will make a Renesis 2 engine that will allow a safe add of FI either by them or by the aftermarket people.

??? Brilliant deduction sherlock.

So why all the hoopla on the aftermarket turbos and superchargers, if at the end the engine is going to get hurt? So there is no sense to have a discussion on FI on this board because it will be just destructive to the RX8?. Why are we discussing aftermarket products that wont be of any benefit to the car?If only you knew you wouldn't call me sherlock( I hate name calling).

So youve done engine analysis of a turbo'd renesis and know all this for a fact eh?

Just the fact that there has been 4 ECU flashes in the 10 months the car has been out shows one thing at least. mazda still doesnt know evertything there is to know about how the Renesis works. Know what else I know? A turbo on this car can be done no problem. Tuning is a bit of work, but so is any car where a turbo kit is being developed. Can a FI solution be done on the Renesis without causing major damage or major engine wear? Most likely yes. Dont know where you deduced that FI solution wouldnt work with the car. Hell, the turbo'd 8 I rode in was much smoother than my car.

Me thinks you need to read up a little more. For example, how the engine tuned for racing is putting out over 75HP more to the wheels over stock setups. Not turbo'd, just tuned. The Renesis in an 8 is nowhere near being at it's max. At all.

I dont doubt it could be done. I know that a bunch of people are working on the project. It just that, is strange that Mazda did not coup on a FI for the renesis like they did with the 3rd generation RX7's.

Well it could be done but definite not on my car just yet. Wait for 2-3 years and let THEM discover the problem. I hope this make sense. It takes a brave soul to be an adventurer. So I never be a Columbo or Captain Cook :D

Why is that strange? The FD wasn't exactly the most successful car on the planet, in terms of sales. So, they went back to their roots...normally aspirated, good overall driving experience, (hopefully) reliable...and then added in a dose of practicality for good measure. Neither the first nor second generation RX-7s came out with a turbo at the start...I would consider the 3rd gen to be the exception to the rule, not the standard.

jds

Originally posted by rx8 dx
I dont doubt it could be done. I know that a bunch of people are working on the project. It just that, is strange that Mazda did not coup on a FI for the renesis like they did with the 3rd generation RX7's.

i agree with bureau13 that mazda just wanted to back to their roots and go with the NA type. I've read that the FD had lots of problems and little kinks with the twin turbo and just wanted a more reliable car with the RX-8 and the insurance would be much higher with a FI car.

there isn't a doubt in my mind that you can add a turbo or a supercharger on this car its just taking a little longer because its a rotary engine IMO. You'll see a lot more FI alternatives in the years to come for this car dont wry

reason why the fd didnt do so well after a certain time is the market for supercars.not cause of turbo model/reliability
same reason why a supra couldnt sell at show room dealers $$$
lets just face it mazda is wacky at times but i love them for
keeping the rotor alive.turbo or not.
but damn i wish my 8 at least got p-p turbos.

There have been some aftermarket tuners out there putting turbos on the car and promising a production version eminently only to never be heard from again (some on this forum). Something is difficult....?

Its sad to see the aftermarket support -- for engine parts -- for a car like the Evo (and even the Z) which doesn't seem to sell in any greater numbers than the RX8, while almost a year after release, there really isn't anything of significance for an RX8.

The demise and decline of sales of japanese sports cars is not just a fault of the market but also a partial fault of the Japanese manufacturers themselves. They went all out and built the best car money can buy but made the mistake of charging for it. There is a certain price point where perception and prestige matters to the mass market of those who could afford a $$35k+ car. That was just an entry price. In the early 90's, that was a lot more than it is now.

Mazda did no service to itself by building a car, while explosive and the closest thing to a track car at the time, had the reliability of an exotic that people, due to said prestige, were willing to contend with. It was a supercar accessable by the masses which is both good and bad.

Of course emissions did not help. Turbos hurt emissions, reliability, and cost. 3 strikes right there.

Fact is it was still too expensive for the American market as it is still a Mazda. Slap a turbo on the RX8 and the complexity and cost go up. People talk a lot, but are there enough people willing to step up to the plate and purchase a $40k Mazda?

I think a turbo renesis is more than feasible, but I am actually rooting for an increase in displacement to 1.5l as I really do like the way this car drives in NA form. It is solid, reliable, linear, and simple. Very straightforward and I like it that way. I had 150k on my 84 GSL-SE and it ran great. I would like more of the same.

Originally posted by zoomed
There have been some aftermarket tuners out there putting turbos on the car and promising a production version eminently only to never be heard from again (some on this forum). Something is difficult....?

Its sad to see the aftermarket support -- for engine parts -- for a car like the Evo (and even the Z) which doesn't seem to sell in any greater numbers than the RX8, while almost a year after release, there really isn't anything of significance for an RX8.

The difficult part is ECU tuning. With personal experience putting a turbo on a NA tuned ecu car, I can tell you it is not easy.

Given the choice, I'd go with a naturally aspirated 3 rotor renesis over a turbo or supercharger. But since that's not really available... and FI will be first, most likely, then FI it will be. :D

1) For cost reducing reasons, OEM engine are always stressed to the limit, minus a safety factor.

2) Increasing thermal and pressure strain on an internal combustion engine will always reduce its long term durability.

PS : always = 99% of the time

rx8 dx, how old are you??

Originally posted by rx8 dx
After almost a year since the release of the RX8, I come to the conclusion that Mazda knew that adding a Turbo to the renesis was going to be hard on the engine causing problems to the structure/function aspect of the engine and decided no to add it. I believe that aftermarket will be able to make a Turbo system for the RX8, but either is going to be tough on the engine and thus reducing the life or it will completely blow up the engine. I think that the engine as it ,is already max out to perform without risking engine lifespan. Maybe Mazda will make a Renesis 2 engine that will allow a safe add of FI either by them or by the aftermarket people.

Car company's don't make cars turbo ready. If they did they would make and release turbo kits so you can purchase your car and a turbo kit to go with it, and may be have the dealership install it and tune it for ya.
Thats what turbo(s) are for. You chose the right one for you car depending on how you would like to use your car,
IE: Drag, road and track, daily driver.
Now you have to find a shop that will touch your car! or one that knows what the hell they are doing and install the Turbo and tuned your car.
You can turbo anything as long as you have the green $$$$$.
But the real questions is; "Should you add a Turbo to your vehicle?", not; "Can I add a Turbo to my vehicle?".

Mazda didnt design the renesis or rx-8 for a turbo, they designed it to be the best NA rotary they could make.

IF they make a turbo version I'm sure they'll make any changes they deem necisary (especialy after the 4rd gen heat problems etc).

I doubt they will make a turbo version.

mazda will not make a turbo version of the RX-8. it will be too damn expensive and mazda doesnt want that. that was why the rx-7 was so expensive, because mazda wanted to compete with porsche. by the end of the summer, mazda will show their supercharger that will have a 40% increase in horsepower and HKS will show their twin turbo project that mazda has been watching over. So rx8 dx, i dont know where you got your info. if anyone plans on going FI on the RX-8, expect major internal work regardless, and that applies to all cars, pistons or rotary. the more horsepower you want, the more work that has to be done internally to hold the power.

Duff man:OH yea!

Forget about the RX8 and turbo's anyone else notice how HOT Kari is?? I can't believe that I was the only one to point this out, with that said lets carry on. I read in Car and Driver that Mazda was working on an electric assist tubo for the RX8.

Originally posted by TotalKaos
Forget about the RX8 and turbo's anyone else notice how HOT Kari is?? I can't believe that I was the only one to point this out, with that said lets carry on.

And I can't believe how much DOMINION looks like Dave Chappelle.

It's an avatar, not a web cam. I'm not saying that the pic isn't Kari, just that I'm not going to assume it is. Therefore, I didn't say anything. Avatars are only good for identifying users w/o reading usernames (which sucks if you are trying to find MazdaManiac's post in a thread). Either way, Kari's avatar is hot. That's all you can REALLY say.

And to actually contribute to the discussion, even though it has been said: Adding a turbo to any car will increase engine wear. That's just how it goes. If you want more power, you sacrifice stock engine life. You just have to decide if it is worth it to you. The '8 can take a turbo like any other car can, as long as it's suited for the application. Just don't do more than the internals can take, and you'll be fine. If you want more boost, replace internals, and repeat. It seems pretty obvious.

Hmmm, the Renesis has the strongest Mazda seals yet, so the internals shouldn't be that much of a problem, and since it has a high compression ratio so it doesn't need to run high boost. Omicron I am pretty sure you realize that a 3 rotor Renesis is basically out of the picture (side intake and exhaust for middle rotor) and it would be a pretty heavy engine as well. I would bet Mazda would do a larger displacement engine if they can't get their electric assited turbo to work well.

Originally posted by Rotarian_SC
Omicron I am pretty sure you realize that a 3 rotor Renesis is basically out of the picture (side intake and exhaust for middle rotor) and it would be a pretty heavy engine as well. Yup. :(

OK, Heres one to help the nob's with questions...
Q: If adding a Turbo/SC if not good for your engine then why do it in the first place?

Originally posted by DOMINION
OK, Heres one to help the nob's with questions...
Q: If adding a Turbo/SC if not good for your engine then why do it in the first place?

Because it gives it more power. If you don't want any more power than what a NA engine can provide, you don't need forced induction. You just have to decide how much power you want vs. how much longevity you are willing to give up. Not that I think there is any scientific formula you could apply across the board, but simply more boost = less longevity. If you get a car and keep it 5 years then sell it / throw it away, boost it as much as you want without blowing up the engine, and have fun. If you want to keep it 20 or 30 years, you want to boost it not very much / not at all, and / or beef up the internals enough to handle the additional stress.

I hope you nobs leard something from this.

i learned that a few people hadn't seen kari's pic before;)

also mazda has said on more than one occasion that the renesis is built to take boost, so you will see a factory boostd renesis "at some point". the talk right now is electric assissted turdo for 2006

Yea like me.

mazda doesn't even know what type of oil the rx8 needs

If the RX8 gets factory FI it will more than likely be a supercharger, the Renesis is a better candidate for it and it is easier to engineer (Packaging it in the 8 is a lot easier and less heat issues)... There is also talk about a RX7 replacement with a 1.5 liter Renesis (wider rotors) or 3 rotors (That’s right a regular production 3 rotor engine!); only time will tell... I have good sources, but until then even reliable rumors are just that...

One thing for sure, it will be a lot of fun…

Originally posted by mikeb
mazda doesn't even know what type of oil the rx8 needs

HAHAHAHAHAHA.

Originally posted by cortc
If the RX8 gets factory FI it will more than likely be a supercharger, the Renesis is a better candidate for it and it is easier to engineer (Packaging it in the 8 is a lot easier and less heat issues)... There is also talk about a RX7 replacement with a 1.5 liter Renesis (wider rotors) or 3 rotors (That’s right a regular production 3 rotor engine!); only time will tell... I have good sources, but until then even reliable rumors are just that...

One thing for sure, it will be a lot of fun…

I'll buy into a SC or Turbo RX-8 from Mazda. That seems pretty likely considering all the love for the RX-7's turbo system and the desire to push the RX-8 to the next level.

I'm not sure I buy the 3 rotor RX7. I know there are 3+ rotor cars floating around the world, but it seems, at least, quite a ways off. As I'm sure many have heard, something would have to happen with the side port on the Renesis for the center rotor. They could move back to the older way for the center rotor, but it seems some inefficiencies would develop w/ the center vs the outer rotors.

I'd bet on a 1.5 liter Renesis. They've still got so much they can do with it before they need to ditch it for a "20B" Renesis. I wouldn't even doubt a turbo or SC 1.5 liter...

A thiner middle rotor that would not exceed the volume for the intake and exhaust is possible.

Once again I need to write a small book as a reply! Here goes...

First off, to address the initial observation, what is your proof? Do you know the designers personally? Are you one of the designers? If the answer is no to any of these, you don't know for sure and are therefore speculating based on what you believe to make sense. Let's go over some historical facts about Mazda's trends and the rotary engine. I'll start with the 1st generation RX-7 and work forward from there.

1978: the 1st generation RX-7 emerges as a 1979 model. It is powered by a 95 hp 12A engine. In 1981 emissions changes which resulted in using a catalytic converter rather than a thermal reactor helped bring horsepower up to 110. I'll bet they didn't see that one coming 2 years earlier. In 1984 the GSL-SE was offered to certain markets. They increased the engine size to a 13B and horsepower jumped up to 135. In Japan they retained the 12A but added a turbo which resulted in nearly the same power as the nonturbo 13B versions.

1986: The 1st year of the 2nd generation RX-7. It was available only with a 146 hp naturally aspirated 6 port 13B. 1987: The Turbo II hit the market with 170 hp. In 1989 each model was revamped. The nonturbo went up to 160 hp and the Turbo II went up to 200 hp. The Japanese market received a special limited edition version of the Turbo II known as the Enfini IV. It had 215 hp.

1993: The 3rd generation RX-7 emerges. Mazda designed this car as a no holds barred sports car. They had performance goals in mind that could not be accomplished without some redesigning of the 13B. Their goal of 250 hp (but attained 255) could only be achieved through turbocharging. You and I know this isn't only true but to hit their margin of safety and emissions regulations, at the time it was true. Mazda took many shortcuts on this car. They installed 2 very small turbos to help response time. The biggest issue was that they spin so fast and get so hot, they aren't reliable. Another issue Mazda had was the internal coolant seals. They changed the material they were made from and reliability here went down. To compound cooling issues, the radiator was pathetically small and the engine bay was so cramped that air could not flow well through it. All of these factors combined with a sticker price approaching almost $40K by 1995 caused it's demise in this country. Mazda continued to develop and improve this car until the 21st century when it finally had 285 horsepower.

Enter the RX-8. A car that is designed to be a COMPROMISE car for the person who wants the feel and performance of a sportscar with the drivability and functionality of a sedan. Mazda had horsepower goals that up until the Renesis could not be met without the aid of forced induction. Mazda knows the engine has far less average horsepower without turbos, but they didn't have neck snapping power in mind when they designed this car. They wanted a smooth linear deliver of power and that is what this car has. They had performance goals in mind and they hit them with the current setup. So this begs me to ask these questions.

If Mazda hit their projected performance numbers without forced induction, why would they need a turbo? A turbo adds complication, it is something else to go wrong, and it is more expensive to manufacture. Now before you think I am agreeing with the original poster, I have another question.

Looking back at the history of the RX-7, why is there any doubt that a more powerful version will not appear? A more powerful version of every generation RX-7 has always appeared. Look at the first years of each model. Now look at the only year RX-8 we have available. See a correlation? I do. They each only have 1 power level available for that year. Coincedence? I think not. In 1979 did anyone except Mazda know for sure that there would be a turbo version or at least a larger engine version available later? I doubt it. In fact I'll bet that year, Mazda didn't even know it. Every RX-7 that ever came without a turbo, had an upgraded version availble at some point in it's lifespan. It's really quite simple. Manufacturers test the waters with a lower, cheaper model. They judge potential sales by this. If the car does well in it's current trim, they'll offer an upgraded model. If sales are low, why spend more money on a higher level of car that won't sell? Just because you add power to a car doesn't mean that sales will just miraculously go up. They will in this car, but they weren't even sure if it would sell at all yet alone so good.

You can almost bank on the fact that a more powerful version is on it's way. This leaves us with the debate over how will they increase power? Some say larger displacement. I say no to this only because of current gas prices and the cars current gas mileage. This will definitely hurt economy on a full time basis. Others say turbocharging. This may happen. The biggest current issue is with emissions regulations. A turbo absorbs some heat from the exhaust system. This means that the cat will be slower to get up to temperature. The WRX actually has a cat before the turbo. That solves the issue of cat temperature but creates the potential for drivability issues. Having driven a WRX however, I can tell you it isn't bad at all. The rotary exhaust is extremely hot. Placing a cat this close to the engine will almost certainly result in short cat life. I think with the advent of electric assist spooling turbos which Mazda has shown, they can solve some issues about cat location and turbo spool times. Only time will tell but I think a turbo still has a chance of appearing on this car. The last group think supercharging will appear. I favor this group although I can't discount the viability of a turbo. A supercharger won't create all of the emissions issues that a turbo will. A supercharger also isn't an exhaust restriction. When a turbo isn't under boost, it still hurts power but restricting flow. Consequently when today's supercharger isn't under boost, it has a bypass valve that opens to maintain efficency and mileage. The blower itself actually only takes about 1/3 of a horsepower to turn when not under boost. Air still flows through the rotors of the supercharger. If you disconnected the belt, it would still spin from airflow. That isn't much parasitic loss. These features still allow you to retain economy, emissions, and get added power. It offers the least compromise of every system.

Of course someone is going to say that the Renesis has too high of a comprssion ratio so it won't work good. Once again lets look at history. When the turbo 12A came out in the 1st gen RX-7, Mazda installed lower compression rotors. When the Turbo II 2nd generation RX-7 came out, they installed lower compression rotors. The 3rd generation RX-7 retained the lower compression from the 89-91 Turbo II's. Why wouldn't they do the same here? They always have! My logic is to keep the current compression ratio but run less boost. Anyone who has sat through hours of my other posts knows the difference between static and effective compression ratio and how the static compression ratio (10.0:1) isn't what determines power.

In summary what you just spent the last half hour of your life reading is simply this, they probably will offer a higher power version of the RX-8 one day and if it has forced induction, they will probably install lower compression ratio rotors. They always have. Why break from tradition? Simple, isn't it?

Rotarygod you are right. Mazda is not going to FI the current version of the Renesis,at least for now.

Two plan strategy for Mazda and the incorporation of FI to the renesis:

Plan A: They are aware of all the FI aftermarket in development and plan to "watch and wait" to see how the current version of the engine takes it. That way they are not investing in any testing or spending money in repairs and want us to be the guinea pigs.

Plan B: If plan A doesn't work, then they will modify the original version of the renesis with one that will be able to handle the failure points that the first engine revealed when it was FIed.

rx8 dx, I think you're putting words in rotarygod's mouth. Who says Mazda isn't investing anything in testing FI on the Renesis? Also, I would hardly call using lower compression rotors on a near-future FI Renesis a major redesign, nor does such a choice indicate that they tried and failed to do it the other way. As rotarygod said, Mazda has always gone with lower compression rotors when they added a turbo, but there are other ways to do it (i.e. run less boost).

jds

I agree with you jds, if Mazda wanted to watch and wait then they would want to see FI projects being done and would help those companies crack the ECU.

Instead of bigger/wider rotors, or adding FI...how feasible would it be to go with option C, higher RPM's? What is the limiting factor for the Renesis, or rotaries in general? Something about "10,000 RPMs" just sounds nice. :cool:

No reason the Renesis can't be taken up to 12,000 rpms for that matter. The RX-8 would need some drive-train modification to have much life at those RPM's, but the engine would be fine. Emissions, however, well, good luck! Say by the the cat and have fun offroad/track only!

If I were a betting man, I would put money down that Mazda's first factory FI RX-8 will be using the 10:1 ratio that it uses now. Sure, historically they've always dropped the ratio (in my opinion just to make life easier tuning) but with this fancy-shmancy new engine that has won all kinds of awards I think they'll keep it as is and run the boost in the 5-7psi range.

As far as all the talk concerning the RX-8 drive train or the Renesis in particular not being able to handle FI, I have to agree with a few of the posters above and say it's purely a tuning issue. I don't see any single weaker link in the picture compared to older engines, and many parts are stronger than before. The higher compression ratio means less boost unless you want to build a bomb, but the key is solid a/f and timing under all situations. The piggy back guys will get there no doubt.

wouldn't more RPM = more emission, hotter engine, decrease power plant life.

Actually I just got done watching a video that came with one of my mags on the development of the RX-8. I has a section where Kenichi Yamamoto dubbed ""Mr. Rotary" takes a prototype out on the track at Miyoshi. He is the Department Manager for the rotary engine development at Mazda. He pretty much says that the Renesis provides what he considers to be the rotary feel... smooth linear power.

As for rotarygod's analysis. It's very good... but it doesn't address one issue. This is an RX-8 not an RX-7. Does Mazda plan to offer both a high powered RX-8 and a simliarly powers RX-7? Isn't there a sales problem with that picture?

Originally posted by BaronVonBigmeat
Instead of bigger/wider rotors, or adding FI...how feasible would it be to go with option C, higher RPM's? What is the limiting factor for the Renesis, or rotaries in general? Something about "10,000 RPMs" just sounds nice. :cool:

Cant. Rotaries dont have the tourq like a piston Engine.

rotarygod, It would take me a 2 days to write that.

Originally posted by Japan8
As for rotarygod's analysis. It's very good... but it doesn't address one issue. This is an RX-8 not an RX-7. Does Mazda plan to offer both a high powered RX-8 and a simliarly powers RX-7? Isn't there a sales problem with that picture?

Actually the initial point of it was that no one but Mazda engineers know for sure. Since the car is a compromise and not a true pure bred sports car, adding power wouldn't necessarily put it in that realm. It would just be higher powered. I believe there is still room for a true 2 seater sports car. Will there ever be a higher powered version of the RX-8? Almost certainly. This doesn't mean that it will have forced induction. When I say higher power, I'm not necessarily saying 75 or 100 more horsepower. It may be only 15 horsepower from better tuning but it's still more power. This is what I find plausible.

Something else to take into consideration is that Mazda has publicly stated they intend to produce a Mazdaspeed version of all their cars. While this isn't a guarentee of a turbo RX or even a more powerful NA car, more power certainly seems to be part of the Mazdaspeed formula.

Just as an aside on turbocharging the Renesis. With a 10.0-1 static compression ratio low boost is the only option, but who declared low boost a problem. If all you want to do is add a few pounds of boost, say 4-6 pounds for the sake of arguement, then you will only need a small turbo. which means that you can acheive a very fast spool time to max boost. Using a small turbo is probably the best way to go if your going to put one on a RX-8. A small turbo can be made to spool so quickly that it will be practically invisible in terms of the driving experience. The downside is that the familiar feel of boost kicking in won't be there because you'll be at full boost so shortly after idle.

I should add that when I say small I mean small. A turbo that would be too small to make big numbers on the dyno. Dyno numbers are good for tuning or bragging but if you just want enough power to make a RX-8 run with the big dogs 65-75 hp should do it. To put those numbers in perspective, assuming the factory claims are true, you would end up with 303-313 hp total and run mid to high 13's in the 1/4 mile.

I bet the 8 will never see a turbo because it will consume too much gas. I mean 10 city-15 hwy...how would that look on the sticker of a four door?

I think they are going to do minor tweaks to the N/A renesis over the next few years....intake tuning+exhaust tuning+compression tweak+ecu tuning+upped redline or displacement. Anyone of those seem feasable. They may gain 10-30 h.p. after some more tweaks to the current set up.

I think the turbo will be used for the future RX-7 possibly, or not at all. They may even use hybrid electric for torque and up the rev's for horsepower. That would bring the fuel efficiency back. Of couse, they would need lighter weight battery technology i'm sure. Or, they may do more displacement or three rotors,.....BUT that won't be fuel efficient either. I think new technology will take the rotary even further and the Renesis is just a fresh starting point.

Originally posted by RenesisX-8
I bet the 8 will never see a turbo because it will consume too much gas. I mean 10 city-15 hwy...how would that look on the sticker of a four door?



Those numbers are pure fiction. That would ONLY be true if you floored it everywhere you go. Just because a car has a turbo doesn't mean it is spooled up and providing boost. Most of the time it is just free spinning inline with the moving air. No extra air, no extra fuel needed. With regular driving you'll probably see no less than a mile per gallon drop in gas mileage. People only see worse mileage because the car is so fun it is hard to keep your foot off the gas.

Yep.... My Fd with over 80k original milles gets the advertised 17 city & 25 hwy. Like RG said, it all depends on how you drive.

Originally posted by rx8 dx
I dont doubt it could be done. I know that a bunch of people are working on the project. It just that, is strange that Mazda did not coup on a FI for the renesis like they did with the 3rd generation RX7's.

Well a turbo charged rotary isn't exactly the most emission friendly car in the world, getting it to pass CARB inspection would a project all in its own. Mazda didn't turbocharge the vehicle for plenty of reasons and reliability was probably on the list but not before budget and emissions. Having a basis for a naturally aspirated car, that would mean in order to turbocharge the RX-8 they would have to go all the way back to the drawing board, design a whole new engine and go from there.

So Mazda need to go back to the drawing board and build the "Renesis II" engine with the FI package that includes a new ECU/Tuning, because a lot of cars for 05 and 06 (Nissan,Acura, even Honda)will have so much HP that RX8 owners(Including me) will not be happy with the old stated 238hp.

Why exactly would they need to go back to the drawing board and build a new engine? This engine has the strongest internals of any production rotary engine, stronger than the FD internals. And if they did redesign the engine all they would need is lower compressions rotors (which I believe just involves a little calculus, because on a side note i remember my son showed me a problem he had in high school calculus that involved finding the compression on a 13B based on the curve of the rotor or something, I have forgotten the calculus needed) and even if it needed more than just some calculus, it isn't like they have to redesign the housing, or the ports to a large extent. I would favor OEM the same rotors on the Renesis because:

More off boost power
Smaller turbo, so it spools quicker
Less boost needed, less stress on the internals

The lower compression is only needed for high power, when you can't gain power by adding more boost, and I would personally not be modifying the engine to that extent.

Wow, I think RG and I need to have a competition for the longest post ;)

Here's a very simple solution for Mazda that is reliable. Change ONLY the rotors to lower compression ones and retune the ecu. Add forced induction in moderation. Simple isn't it! How would that be going back to the drawing board?

You would think that Mazda have a group of highly knowledgeable builders and designers, but from what I can see: In this forum there is much more talent (Rotary engine dynamics) than overseas. They should have consulted with the rotorheads here in the USA while there were working on the RX8 project. Maybe that way, at this time we would have been enjoying a super engine.

Can someone make rx8 dx stop posting? Or at least send him to the Lounge section. I think he may be a junior high student.

Agreed on that one. Does he think that he should have been consulted to build the Renesis, because he seems to be making these claims like it can't take boost because I guess he thinks he is knowledgeable about the Renesis. I would have to say I would go with RG over him, as would many on this forum I hope.

Originally posted by takahashi
Well it could be done but definite not on my car just yet. Wait for 2-3 years and let THEM discover the problem. I hope this make sense. It takes a brave soul to be an adventurer. So I never be a Columbo or Captain Cook :D

There's been a lot of figures, facts, and fiction in this thread.....but the one undeniable fact is that Columbo was not an adventurer. He was a dude in a trenchcoat with a dicky eye.

Factually Yours, Gomez.

:D

I say that Mazda should build a NA 3 rotor Renesis w/aluminum side plates to reduce weight. Overall the car would probably cost as much as a FI 13b and have a ton more low end. Mazda could easily sell a ton of these higher powered 3 rotors because not everyone has confidence in the reliability of a FI rotary. I know I would easily pay thousands more to have that engine in my car.

Time will tell...

I don't think Mazda will do a 3 rotor, that would basically reverse the changes and advances to the Renesis, and I think it would be more likely for them to just increase housing size than add a smaller third rotor in the middle because then there are new balancing problems, etc

Can I get a stronger drivetrain before we start worrying about more power? HAHA...All I really want or need would be the 25-35 horsepower that the CZ gives, but from the factory....that's all. I would like to see a higher performance rotary in what it really belongs in.......a 2 seat coupe.....you don't have to call it the RX7. I don't care what they call it....

Originally posted by rx8 dx
I think that the engine as it ,is already max out to perform without risking engine lifespan. Maybe Mazda will make a Renesis 2 engine that will allow a safe add of FI either by them or by the aftermarket people.

FI will reduce the overall lifespan of ANY engine. Rotory or not. Unless of course its your grandma driving it and the turbo never has a chance to spool up. Nonetheless FI is more maintenance and more $$ on any engine, in any car. It has nothing to do with the fact that theres triangular thingies spinning around in there.

Maybe Mazda will make a Renesis 2 engine that will allow a safe add of FI either by them or by the aftermarket people.

Maybe Kerry will win the election too. It all boils down to one basic, simple common denominator. Every car manufacturer around the world that exists and once did exist spends loads of money on R&D for piston engines, and has been doing so since people started calling the horseless carriage a "car" for short. The rotory has never seen this sort of attention and thus it'll take more time and more money to find the sort of common knowledge about things like emissions, fuel economy, and FI that there is with bangers. When you really look at the big picture you wonder how it could ever possibly be economically viable for Mazda to pursue such a thing like the RX-8 to begin with. But then to go redesigning the whole engine for some extra weight under the hood, a unique wooshing sound and 50 extra ponies? I just don't see it... Its those kinds of aspirations that can bring a auto manufacturer to its knees. DeLorean anyone?

Originally posted by Rotarian_SC
I don't think Mazda will do a 3 rotor, that would basically reverse the changes and advances to the Renesis, and I think it would be more likely for them to just increase housing size than add a smaller third rotor in the middle because then there are new balancing problems, etc

You really don't know what you are talking about! If Mazda didn't want to spend the buck on retooling for the intermediate housing and eccentric shaft we would have an engine that was 3 inches longer and it would have full size exhaust ports in the intermediate housing. Same thing could be done with a three rotor.

Originally posted by fxdsconv2000
A thiner middle rotor that would not exceed the volume for the intake and exhaust is possible.

This is what I was responding to, sorry about not giving the quote before. If Mazda was going to increase displacement, they would not use a thinner middle rotor, because they could just achieve the same thing by using wider rotors in a two rotor. Also I would be willing to bet that the more powerful engine is not a 3 rotor. 3 rotors weigh a lot, the old 20B weighs double the 13B, because there are lots of balancing issues to be worked out. If Mazda wants an engine that can produce 325hp or so, why would they choose a 650lb 3 rotor engine, a >500lb two rotor, or a >400lb turbo two rotor? I the less just so my numbers don't look conservative, but is the increased displacement in a Renesis going to account for 200lb more, or will a turbo add a 100lb to a Renesis, I think they will each add much less weight that that, and the 20B weighed over 700lbs, so that is at least a 250lb and 150lb weight difference for the 1.6L (I've heard 1.5L as well) and turbo engines compared with a 3 rotor.

Originally posted by T-von
I say that Mazda should build a NA 3 rotor Renesis w/aluminum side plates to reduce weight. Overall the car would probably cost as much as a FI 13b and have a ton more low end. Mazda could easily sell a ton of these higher powered 3 rotors because not everyone has confidence in the reliability of a FI rotary. I know I would easily pay thousands more to have that engine in my car.

I agree with you there, except as far as I know Mazda had trouble building aluminum rotaries that could last, but this is the only way I can see Mazda building a 3 rotor, if it is made out of Al.

Originally posted by zoom44
i learned that a few people hadn't seen kari's pic before;)

also mazda has said on more than one occasion that the renesis is built to take boost, so you will see a factory boostd renesis "at some point". the talk right now is electric assissted turdo for 2006

Are you sure? Everything I've read says an electric assissted turbo for the Renesis... not for the RX-8. Could this be the new RX-7 engine?

Originally posted by Jerico
FI will reduce the overall lifespan of ANY engine. Rotory or not. Unless of course its your grandma driving it and the turbo never has a chance to spool up. Nonetheless FI is more maintenance and more $$ on any engine, in any car. It has nothing to do with the fact that theres triangular thingies spinning around in there.



Maybe Kerry will win the election too. It all boils down to one basic, simple common denominator. Every car manufacturer around the world that exists and once did exist spends loads of money on R&D for piston engines, and has been doing so since people started calling the horseless carriage a "car" for short. The rotory has never seen this sort of attention and thus it'll take more time and more money to find the sort of common knowledge about things like emissions, fuel economy, and FI that there is with bangers. When you really look at the big picture you wonder how it could ever possibly be economically viable for Mazda to pursue such a thing like the RX-8 to begin with. But then to go redesigning the whole engine for some extra weight under the hood, a unique wooshing sound and 50 extra ponies? I just don't see it... Its those kinds of aspirations that can bring a auto manufacturer to its knees. DeLorean anyone?

Well said! This is exactly why I don't want Mazda to FI the 8, and I have doubts about an FI version appearing. Once you combine this with the thought that they may be planning a more hard core 2 seat rotary... there a realy serious question of where is this care going to fit in the lineup?

Originally posted by Rotarian_SC
This is what I was responding to, sorry about not giving the quote before. If Mazda was going to increase displacement, they would not use a thinner middle rotor, because they could just achieve the same thing by using wider rotors in a two rotor. Also I would be willing to bet that the more powerful engine is not a 3 rotor. 3 rotors weigh a lot, the old 20B weighs double the 13B, because there are lots of balancing issues to be worked out. If Mazda wants an engine that can produce 325hp or so, why would they choose a 650lb 3 rotor engine, a >500lb two rotor, or a >400lb turbo two rotor? I the less just so my numbers don't look conservative, but is the increased displacement in a Renesis going to account for 200lb more, or will a turbo add a 100lb to a Renesis, I think they will each add much less weight that that, and the 20B weighed over 700lbs, so that is at least a 250lb and 150lb weight difference for the 1.6L (I've heard 1.5L as well) and turbo engines compared with a 3 rotor.




Your 20b weight calculations are off a bit. 20b's don't weigh that much(550lbs max with all accessories in turbo charged form). Its the accessories(turbos & manifold, center plate extra rotor ect) that really increase the weight. If a "factory" style turbo is added to the 13b Renesis, I'm pretty sure the overall engine compartment weight will increase nearly 100lbs(turbos,cast iron manifold, plumbing, IC, ect). A 20b short block weighs about 100lbs more than a 13b. So if you compare a FI 13b Renesis to a NA 20b, you would come pretty close to the same weight under the engine compartment. Also if 20b is build with aluminum side plates, the weigh would be further decreased. Mazda can easily do this, it just won't ever happen.:mad:

Well I did do a search and about all the websites I found stated a 350kg weight for the dressed Cosmo 20B.