3 Rotor Motor
 

Now the stakes are getting higher and higher in the performance arena. Lexus will unleash a V-8 in the Is-300, maybe being named IS-430. Big engine, small car ='s phenom performance.

Mazda must compete with these monster motors with a monster 3 rotor motor or even 4 rotor motor. This will effectively negate any perceived torque deficiency, yet will keep the high revving performance that the rotary is known for, keeping Mazda on the top ent of the performance spectrum where they belong.

Mazda has previously manufactured a 3 rotor motor in the Eunos Cosmo. Furthermore, 3 rotors is preferable to any type of forced induction.

Waddyathink?

Re: 3 Rotor Motor
 

You, know.... I can't argue against anything he said!...

Absolutely,... we WANT, we NEED at 3 rotor renesis. Forget forced induction!

I hope Mazda doesn't join the stupid horsepower war that is going on now. Altimas and Accords with 240 HP? Give me a break. Who needs that kind of power? Give me better handling than these understeering pigs. I'll gladly trade 40 HP, especially if we got the Euro accord here.
More motor = more weight over the front wheels = sloppier handling. No one who is in the horsepower war is working to get the handling right. Which is why the Mazda6 is shining so brightly right now. It may be down a few ponies, but it can carve up a road better than its competitors.
If Mazda should join any war, it should be the "add lightness" war. Of course, its an easy war to win when no one shows up.

Of course we shouldn't just add power without concideration... but I think there are more powerful cars which do handle well.

I'd just prefer to see a 3 rotor renesis than a turbo ... Of couse there are people who will use it in a horsepower war, but I believe there are real applications for that sort of motor.

Adding lightness is always a good thing!

yes, i'd have to agree that a three rotor RENESIS would seriously S#!T KICK a comparably sized V8 ('cause a 2.0ish 3 rotor is just like a 4.0L 9 cylinder) in power, and would easily compete torque-wise (not that it matters)...

stuck in the next gen RX-7, whoa baby...
let's assume that the RX-8 is in fact going to come out with a 245bhp (hp, not ps) 2 rotor... accounting for frictional losses and added rotational mass, i'd overshoot the inneficientcy saying that max power would be about 135%: 331 hp...

or, let's say that the (undoubtedly) higher state of tune Mazda would have for the RX-7, would have a 145% output: 356 bhp!!

i could see that... think of an RX-7 as a world beater... any price range... holy crap... (BTW, how much power does the Z06 trimmed LS1 V8 make??)

but Don, a 4 rotor??? :eek: that's a little nuts man... if Mazda was in the $300K super-exotic market, with a mid-engine setup (only way to fly), MAAAAAAAYBE i could see that, but no one needs 600 friggin horsepower (it's the equivalent of a 5.2L V12...) in a stock trimmed vehicle... but a competitor with the Viper?? well, ya, okay maybe that too, but Mazda makes sports cars, not muscle cars, right?? hmm...

Z06=405 bhp with like 385 ft lbs of torque

if that's what Chevy's bringing, a 3-rotor RX-7 would hang, quite litterally with it... but at what, equal or (more probably) greater price than the Z06??i hope that Mazda doesn't get into the price tag wars as well... but hp wars are alright... :)
JUST GIMME A NEW 7!!! so as to decrease the value of the FD's... ;)

Re: 3 Rotor Motor
 

Small car + Big Engine = Nose heavy & poor handling.

A V8 IS430 would be utterly laughable on a handling course. It would be a Japanese Mustang! Sure, it would be fast as hell in a straight line.....but where's the fun in a straight line?

We are getting the (vasty better looking) European Accord here. It's called the Acura TSX, available spring 2003. Priced at around $25k, only available with the 200hp 4 cylinder 2 liter engine from the RSX-S. Still FWD so IMO not a competitor to the RX-8.

Re: Re: 3 Rotor Motor
 

I showed this post to the guy I'm working for and he couldn't stop swearing... LOL.

He did (Once he'd calmed down)... point out that this is NOT an american V8... it's all alloy and pretty light so it could be possible to balance the car and make it handle OK...

He's had a load of TVR's all with large alloy V8's and will claim that they handle well so there is a danger that he does have a point... especially since the IS300 was so under powered!

If you consider the the dimensions of the rotary engine generally don excede the size of the transmission housing, I bet they could stuff a 3 rotor into an RX-8 or RX-7 without going forward.

Looking at my 1982 RX-7 GSL, I bet I could do the same thing. It might push the shifter back about 5 inches, however.

Change the balance of the car? I think it would actually be about the same. The added weight is low and the transmission moves towards the center of the car as well. All good things and the added HP will definately make up for the extra weight!!

WOW what a daydream :D

Re: Re: Re: 3 Rotor Motor
 

The IS300 already is nose-heavy for a rear-wheel drive car. Front/rear weight distribution is 54/46. Add a larger engine (alloy or not, the current I-6 isn't that heavy) and things will get worse. Plus, the IS300 is already on the heavy side overall, at over 3400 lbs. It isn't that its under powered, its that it was overweight. 150-200 lbs shaved off that weight, plus a mild massaging of the I6 was what was called for, not a V8. Remember that this is the same bulletproof I6 that was in the Supra. I don't understand the necessity to do a new engine when the old one had gobs of potential.

pelucidor, I've been following the development of the TSX closely. Should be a nice car, depending on how Honda prices and specs it. The TSX is the car the US Accord should have been. You're absolutely right, its no competitor for the RX-8, but I know a few people (my parents included) in the market for a new sedan in the next year, and that might be the ticket, or the Mazda6 (twins seperated at birth!)

Re: Re: Re: Re: 3 Rotor Motor
 

True, although 54/46 isn't terrible... You're right about it being heavy and the I6 having untapped potential... but I guess they will go their own way...

Perhaps they want to do it without a turbo for enissions or somthing? I don't know how heavy the 4.3 engine is... probably not that much heavier though.

I love I6's they sound nice! My triumph 2L I6 sounds awesome.

Any idea how heavy an IS200 is?

Re: Re: Re: Re: Re: 3 Rotor Motor
 

I'm a fan of the sound of I-6's too. Its a shame they are a dying breed. Even BMW has a V-6 under development. :(

An IS200 weighs 2992 - 3168 lbs (depending on what transmission you opt for).

handling in what perspective grip or drift? hehe

As an alternative to the 3-rotor renesis, how about a 2-rotor with increased displacement ....say a two liter two rotor? My guess is that the power output would be similar to a three rotor, but the two rotor version would be a little smaller and lighter since it would require one less steel side plate. Maybe on the negative side, the two rotor wouldn't be as smooth though....but that's what I'd like to see.

Well mazda has made a 2.0L 2 rotor before but it was only a prototype and they never made more than 2 of them. They were taller and wider than the 13B it was called the 21A. Each chamber was 1000 and some odd cc's it made 200Hp N/A and something like 180-90flbs of torque. It didn't rev very high and was a gass hog.

well Curtus wright made a 2 rotor that they stuck in a mustang that had 80 c.i. rotors thats like 1300cc rotors! it had 195Hp
They also made a single rotor that was a 31 litre!!! the rotor was out of a bad B movie! it had somewheres around 700Hp

I just had to show this pic it just blows my mind everytime I look at it .

Maybe just one rotor of the one in the picture on the last post. Just kiddin, I too think a 3 rotor wanky moty would be a great advancement in both torque and horsepower. The weight differential would be easily handled by Mazda. Is there really a possibility of getting a 3 rotor here. What was the car that had it like and when was it made?

Re: Re: Re: 3 Rotor Motor
 

I suppose the IS300 does have the "advantage" of being set up for an I6, so it might be possible to mount the 4.3L V8 farther back in the wheelbase to maintain (or even possibly improve) weight balance. But there's no denying that, alloy or not, it will add weight.

Those TVR's were probably purpose-designed to accomodate a large V8 while maintaining proper balance....the IS300 probably wasn't. And even with alloys, that Lexus 4.3L V8 is still a porker...it weighs more than than the iron-block 4.6L SOCH V8s that Ford uses in trucks.

The Toyota inline 6 has an iron block. It is one of the heaviest inline 6 car engines around. The Lexus V8 is damn light. Look at the GS300 vs GS430 (nee GS400) 53/47 to 54/46. (with all the extra stuff you get for 10K more, that takes up a bunch of weight difference) The IS300 comes in at 53/47, so the V8 shouldn't upset the current weight distribution.



Aren't the rotors 80mm thick, so adding a third rotor would entail about 6 more inches about 3 for rotor 2 for partition, 1/2 thicker radiator?
Think RX-7 :D

"Think RX-7 :D"

yes, my thoughts exactly... :cool:

Just out of curiousity, how many people here would be willing to buy a 35-40k 3300 lb. RX-8?

*crickets chirping*

We're back to wanting more power, more torque, less weight, less cost, more options, more luxury, more colors, bigger brakes, more interior space, nicer materials, etc.

The RX-8 hits a particular mark, and making a significant change like going to a 3 rotor engine would make it a different car. Either you like the RX-8, or you don't. 250 HP should be plenty for me, as long as the handling is up to the expectations that I have after driving RX-7s and Miatas. I care more about handling and real world performance than locker room "whose is bigger" contests. The RX-8 will have virtually the same HP/weight ratio as the 350Z, and a better ratio than anything close in price that can seat 4. If it's already the best in that measure, why mess with the formula and add weight and cost to beat the others by a wider margin? I wouldn't pay for it, and I bet most of those that are asking for it wouldn't pay for it either. If Mazda came out and said that they were going to nix the sub $32k market and just make 3 rotor cars starting at $32k, I bet everyone here would complain about it.
Sure, 250 HP doesn't look as good on paper, but I don't care about bragging rights. If I get one I'll actually drive it and let the people with overweight and overpriced 400 HP monsters spend their time online talking about how weak it is. I'll be the one having real fun.

I'd be WILLING but UNable :)

I don't have that kind of cash right now. 30k is my limit, more or less.

i wouldn't complain, but i would be looking for something else to buy as it would not be what i am after. the rx8 is!:D

I agree but if Mazda could make a 3 rotor 375hp 3150lbs rx-8 a la Corvette Z06 I'd be putting a deposit down right now. :D

Rich,

are you suggesting a 3 rotor RX-8 or RX-7 would add 600 lbs to the total weight of the car?


I feel the running gear would be adequate for the extra ponies. From experience I know Mazda parts are pretty strong.

3300-2970=330. With another rotor and substantially more power, I think there would need to be upgrades to the rest of the car. 300 lbs seems reasonable to me, and 2970 is the only weight I've seen from a reputable source. The actual weight gain isn't important, it would certainly add substantial cost and at least some weight. I don't want any more weight or cost, and I know that some of the people clammoring for an extra rotor are those that have been saying that they want it to cost less than current estimates have it. My point is that they can't have it both ways. The RX-8 hits a mark, and a 3-rotor would hit a different mark. I like the car that they're making, although if I get one it will be a stretch financially. Any more cost and I wouldn't be here. I suspect many others are the same.

precisely, the 3-rotor would be hitting the upper range of Mazda's market, in the new RX-7, supposing one'll come out in 3 or 4 years...

a -2800 lb, +350 hp RX-7 would warrant a near $40K sticker, don't you think?? how much is a Z06?? it'd smoke it. :D

oh, btw, i only know the FD's (ballpark) price in Canadian... just for comparison (inflation excluded, as you in the States had a very stable inflation rate throught the 90's), what was the FD's R1 price?? +$35K?? if the same price for much more car now (becuase inflation would infact dictate a real price similar to that of the FD's, again, supposing) would be one helluva steal, no??

Base Z06 $50,370

hoooooooooooly crap.
that gives Mazda a HUGE ceiling under which to price a Z06 killin' RX-7... i think they could pull it off...

Why stop at the Z06 when you can kill a $80k Viper. This months Motor Trend compares those two directly and the whole time I'm thinkin' with a few mods how bad the rx-8 would make them look and be under $40k and still be able to carry the kids to soccer practice.

if you mean "around a corner" appended to the term "kill", than yes i agree...
but a +550 bhp or whatever gazillion litre V10 the Viper is packing is still a +550 bhp or whatever gazillion litre V10... i don't think that an RX-7, no matter how muscley and expensive it is from the factory would out gun the ultimate contemporary symbol of American machismo in a straight line... i mean, it's not THAT much heavier, but yes, it IS that much more expensive, so the smart money would see where the bargain is... ;)

Dude, you're the one that started the comparison to the Z06, the Viper is not much faster. And since when has anybody here really tried to say that the Rx-8 or fictional new 7 be FAST in a straight line?

The Viper is 500bhp and ran a 12.37 @ 117.21mph. If you wanted to, I think you could make a RX-7 or 8 compete for less than 80 grand.

In case you want to know the Vette did a 12.85 @ 114.36

I've heard, saw dynos that seem to suggest the Z06 is underrrated by GM.. I've seen 400 Whp dynos! :eek: And some people breaking 11's stock with slicks! The Z06 is a bargain in the performance/price ratio.. Now if only it wasn't a Chevy.. Can't stand Chevy interiors..

oh, Viper isn't much faster??? :confused: huh, well, again, i don't know anything about American "sports" cars, and far less about drag racing (other than what can be gleaned through knowledge of racing and other technical stuff in general)...

hmmm... oh, i'm not saying the hypothetical new RX-7 has to be that fast, i'm just supposing that with a mean 3 rotor it COULD be, from the factory... but i definitely think a sticker of $50K US would kill it, because people WOULD buy Corvettes instead, and it would be naive to think they would buy a 7 even if it was faster... maybe those Viper people could be swayed, maybe, but i doubt you could convince most of the Corvette crowd (if they were going to choose one or the other)... so really, my comparison was just for fun, and i REALLY don't think they should price/make the hypothetical RX-7 that expensive when (knock on wood ;)) it comes out...

and ya, the Big 3 have a history of underrating their truly fast cars, don't they?? i mean, not so much anymore, but back in the day... the Corvette is probably the only car that GM could afford to under rate, marketing wise anyway...

As always, I'll back the Z06 and say its the best.

I'm not sure I want to see a 3 rotor engine in the 8. I'm afraid, like Rich points out, that it would add too much weight. A 3 rotor would be great for drag racing, but not for the street.

I am optimistic about a new generation 7 having a three rotor, though. In that case Mazda could work out the weight ratios and again give its loyal followers another 50/50 sports car.

I don't see why it woudl be THAT much more...

The rotors weigh what, something 15 lbs a piece? Then they extend the housing for it and that's another, maybe... 50 lbs? So let's say 100 lbs extra.. I'm sure they can balance that in the car if they wanted to.

Or am I missing something?

I heard the 20B weighed about 130lbs more than a 13B. It is not an excessive amount of weight, so I don't think it would be a big deal in the RX-8. But I have also heard that 3 rotor FD's handling went down the drain after the conversion. If that is what will happen with the 8's than I would rather see a single turbo configuration. I'm not interested in sacrificing handling characteristics for power.

Maybe the 8 won't be able to accomodate a 3 rotor without massive modifications anyway.

I heard the 20B weighed about 130lbs more than a 13B. It is not an excessive amount of weight, so I don't think it would be a big deal in the RX-8. But I have also heard that 3 rotor FD's handling went down the drain after the conversion. If that is what will happen with the 8's than I would rather see a single turbo configuration. I'm not interested in sacrificing handling characteristics for power.

Maybe the 8 won't be able to accomodate a 3 rotor without massive modifications anyway.

"massive modifications" to the RX-7 to get that 20B to fit was probably a big reason the handling fell in the toilet, too... i've heard things like shortening the driveshaft, moving the transmission back, etc...

but when you say the 20B-REW was 130lb heavier than the 13B, which 13B are you talking about?? the 13B-REW?? or the 13BT?? or just the plain ol' 13B??

These were aftermarket conversions though, right?

If Mazda developed a 3 rotor Renesis *drool*, then I'm sure they'd work out handling characteristics to match the engine and car.

Here's hoping for it :)

I know, a mid-engine 3 rotor RX-7! :D Even in 3 rotor it's not going to be a big engine, and the extra weight would be easy to distribute. Also would give it a use for the extra space in the back when they re-adapt the 4-seat RX-8 platform to the 2-seat RX-7.

That would totaly rip a porcshe to peices.

The engine itself is not very complex, so adding another rotor and fabricating it shouldn't be too hard, but re-engineering an RX-8 platform to MR might be impossible, if not expensive.

(conspiracy theory) Maybe that transmision tunnel is high in the RX-8 passenger area for a reason. ;) It might just be the best no-compromise sports car solution.

After reading some of the other posts, I am more in tune with a 3-rotor motor, as same does not appear to increase weight, affect weight distribution too much, at least not so much as to require too much to keep the balance at 50/50. Remember, the motor is set behind the front wheels to begin with.

The 3 rotor would increase torque and horsepower with minimal weight gain.

This RX-8 should compete favorably with the BMW M3.

Give me one now.

I went ahead and weighed some rotary engine parts in hopes to see how much more a 20B weighs than a 13B with similar manifolding etc. Here's what I found:

All weights are to the closest 1/2 pound

FC 13B rotor housing: 13
12A eccentric shaft: 14
13B rotor: 9.5
four port (old) 13B intake manifold: 5.5
'73 rear iron housing (without stationary gear): 28.5
total: 70.5

It's not very complete, but probably pretty close. I mean c'mon, the 20B only has one more rotor, rotor housing, side housing, and a length of eccentric shaft. The extra manifold length on an NA Renesis won't add any significant weight to the engine. I just don't want to see another complicated mess of manifolds and wires like what the 13BRE, 13BREW, and 20BREW had. No turbos mean simplicity, like the rotary itself.

I'd like to see a three rotor Renesis too. I'm just not sure if I'd like to see it in the RX-8. Hmm, on second thought, how much extra could it weigh, and cost?

NA is best. Hopefully for the MPS RX-8 it will be a NA 3 rotor instead of adding turbos. I've never been a fan of any turbos/superchargers. I like it all NA baby :D

you should change your name to Mr.Objective there, Herc... ;)

Mazdaspeed RX-8
 

I think there is some untapped horsepower left in the NA Renesis engine and that 300HP for the Mazdaspeed version is not out of the question. :o

That's great, but can it be done without turbo/supercharging, which is what I want to avoid?

Same here :)

The RX-Evolve
 

That had a 280Hp renesis the 8s 250 is conservitive I bet with some porting and polishing you could gain 40HP out of that thing remember it was made for emissions and milage this time around the basic N/A mods could go along way for the renesis or not. But all I can say is that you can get 300hp out of it without a turbo.
with this zero overlap of the ports is the perfect place to start a bridge port. the exhaust would be mostly closed so you would have minimal overlap compaired to a normal BP and a large increase in power.

The fact is that we don't know yet. But this is the first time we have gotten a completly new engine that has so many unknowns in years. Its gonna take a few years or more of experimenting to figure out exactly what they like and don't like. Its exciting and disturbing to think about what these tuners will go through to find the formula.