Buger

Hi Rich,

I wish the gears were a bit shorter too but Mazda did say from the beginning that two of their main goals were to:

1. Disprove the rotary unreliability idea
2. Disprove the rotary fuel inefficient idea

If Mazda is looking toward the long term future of the rotary, these things may be more important than a couple of tenths of seconds. The production RX-8 may not perform quite as well as some of us were hoping but it will probably sell better to the masses because of some of the compromises. If Mazda can use the RX-8 to make some money and provide economies of scale to produce a new RX-7 for less money, it will be worth it.

Brian

joeandcarol2

I welcome the taller gear ratios. The car needs to be well rounded, not a drag racer. Buzzing along at high RPM at highway speeds on a long trip gets very old. Its not worth this hassle just to be able to say you can beat an S2000 or whatever. The appeal is the great handling, smooth gearbox, good acceleration and overall utility. If you want a racecar, mod it.

rotisserie

Thanks Buger!

I'm just hoping for Aftermarket Support

nk_Rx8

Buger,

I didn't mean to sound like I was ******* you or the RX8 because I wasn't intending to. I would much rather have an RX8 than as S2000 (I really don't like convertibles). But I just meant that I got the impression from reading in the forums that the RX8 definetely would have more mid range power than the S2000, especially since it seemed most people agreed that the RX8 has a broader, better torque curve. And from the previous overlay that you showed, that would seem to provide evidence for it. But your latest graphs seem to show that the two cars perform almost the same, or close enough that the difference is insignificant for me. I have ridden in an S2000 countless times, as a good friend of mine owns one, so I am using it as a benchmark in my head to compare against since we can't actually drive the RX8 yet. And I was hoping that the RX8 would feel like it had more 'pull' to it than the S2000, but so far on paper/graphs, it looks like it will feel the same. I like the way the S2000 drives, but I always felt like I wanted just another ~20-25ft/lbs of torque and it would be perfect. Some of what I want in a car may be provided for by the RX8's fatter midrange, but now the speculation is that it may way 200lbs more than an S2000 which kinda negates that. If the RX8 actually ends up being right at 2800lbs or less, than I think it's perfect for me.

Fëakhelek

I could easily be wrong about this since I haven't owned a rotary, but looking at the numbers for the S2000 and the RX-8 I am not sure what the advantage of the rotary is. The S2000 redlines at 9000rpm same as the RX-8, the torque and horsepower are similar, and I can't imagine the Renesis weighing much less than the 4cyl in the S2000. Can someone tell me why the RX-8 will be better with a rotary than with a 4 cylinder?

wakeech

well, please don't forget that you're comparing the RENESIS to the most highly developed 4 cylinder engine in the world, which is terribly pricey, made by argueably the best 4 cylinder engine maker in the world.
Mazda is something of a David next to Honda's Goliath, and the rotary engine is a young (invented only in the 1950's) as a fundamental concept, so don't think for a second that these two engines are on the same level developmentally.

the first, and biggest reason, is that the RENESIS obviously has a higher specific, AND (more importantly) total output at peak and over a wider range, with its far flatter and more driveable torque curve. things like fuel efficiency, emissions cleanliness, are things i don't know about...
also, (certainly) the block of the RENESIS, with just the moving parts and stuff, i'm SURE is lighter and smaller than just the block and moving bits in the S2000 engine (isn't it the SA20 or something??)... some of those small displacement Honda engines are surprisingly big...
BUT, then again, these two engines should be compared with all the hardware that they need to work... as crate engines, i've got no idea which'd be smaller or lighter, but i certainly wouldn't be surprised to find out the RENESIS is both.

wakeech

seeing this car, with a 3011lb tentative mass coming from the two extra doors, two extra seats (with associated 12" in wheelbase), two more inches in hieght, a real trunk (10.5 cubic feet or something??) stay on par with a 200lb. lighter roadster, which gives up only 10 peak hp, should be nothing short of amazing. of course nothing would be better than to have a car which is magically lighter, but expecting anything south of 2900lbs. is really REALLY counting on too much, unless you're willing to take the base high-power and jettison a whole lot of stuff from the interior of the car.

zoom44

see if you wait long enough someone posts what you were thinking. thanks wakeech:D

wakeech

welcome, rotary dog (?)

ilovepotatos

Hehehe, I keep scrolling down as soon as I see a bunch of numbers, or graphs in Bugers posts!

zoom44

hahaha "set it and forget it" hahaha:D

nk_Rx8

You may be right, but a man's gotta hope right? I'm just so hoping that this car is what I hoping for in a car. Both of my car buddies, knowing what I like in cars/driving, think that this car has my name written all over it and I guess I just have a lot of hopes. And what's great is that one of my buds who was dead set on a Z now has the RX8 as top of his list after listening to me for the past month.:D

ilovepotatos

Dear god. I'm frying in my own oil!

Buger

Hi nk_Rx8,

You are correct in thinking that both cars will feel like they have similar amounts of "pull" when they are driven with the pedal to the metal and shifted at redline. The S2000's power is all in the upper range of it's rpms and shifting at redline will keep the engine in it's powerband very nicely. In everyday driving, people do not *always* shift at redline however. The great thing about the RX-8 is that you don't have to shift at redline to stay in it's powerband.

As an example, think about you in your [insert favorite color] RX-8 on a leisurely drive. You are in 2nd gear going about 43 mph @ 5600 rpm when you shift up to 3rd gear to cruise. At 42 mph in 3rd gear the renesis will be going about 4000 rpms and will still be well within the upper ranges of it's powerband. If you decide to stomp on the gas, you will still feel a nice amount of "pull" that keeps getting stronger as the torque curve increases till it's peak then basically stays there.

Let's say your friend was in his S2000 doing the same thing. He is in 2nd gear going about 43 mph @ 4900 rpm when he shifts up to 3rd gear to cruise. At 42 mph in 3rd gear the S2000 engine will be going about 3500 rpms and will be far from the upper cam of the S2000 engine where the real torque and power are made. If he decides to stomp on the gas, he will have to wait till his rpms raise from 3500 to around 5000 rpms before he starts to feel the significant pull of the S2000 on it's upper cam. Note that the S2000 torque curve stays the same or actually drops from 4000 to 4500 rpms.

This is where you will feel the difference in "pull". The RX-8 will have much more "pull" in the middle ranges of it's powerband than the S2000. Let your friend enjoy the performance of his S2000 while you enjoy the performance and practicality of your RX-8. Remember, he can only fit one girl in his car. :D

Brian

Buger

Hi again Fëakhelek,

Off the top of my head, here are some reasons why to choose the renesis over the F20C (I think that is the name of the S2000 engine):

Higher redline .......... Renesis 9000 rpms vs F20C 8900 rpms
Higher hp ................ Renesis 247 hp vs F20C 240 hp
Higher torque .......... Renesis 159 ft-lbs vs F20C 153 ft-lbs
Wider powerband ..... However you want to measure it
Smoooother ............ Round & round not up & down
Lighter weight ......... Renesis approx 273 lbs vs F20C approx 310 lbs
Smaller size ............ don't know the figures off the top of my head

Why would a 4 cylinder be better than a rotary?

Brian

IGOZMZM

If the S2000 (and many other vehicles) has a "4 banger" then wouldn't the RX-8 have a "2 spinner"? :D

cbj

Well, just to play devils advocate I can think of a few reasons.

1. Fuel Efficiency- Renesis 21/23 (est.) v F20C 20/28 [like it really makes a difference :D ]
2. Reliability- although theoretically the Renesis should be fine we won't really know for sure until 3+ years and 60,000+ miles from now
3. Dealer Mechanical Support- the number of Mazda mechanics with hands-on experience with a rotary engine will be very limited

Having said that the RX-8 is currently at the top of my list when I need to get a car with a back seat. I've been lurking around here since this site was put up (and at rotarynews before that) and am looking forward to test driving the car. As the former owner of a FB GSL and the current owner of a S2000, I think the primary advantage of a rotary over an I4 is the smoothness. I suspect the other factors will pretty much even out because of the 200lb (est.) weight difference. Anyway, very nice analysis of the engines and gearing of both vehicles.

Hercules

If you look at the spec sheets, the quoted gas mileage is 24.4mpg, though I don't know if that's city, highway, or an average of both.

As per reliability, as long as you do your fluid changes on time there's nothing to worry about... the only thing that can go wrong is the apex seals cracking and that's solved by fluid changes, and the other thing that can happen is the rotor housing warping, and that's so unlikely it's not even funny

Trying to warp a cast iron block hehehehehe

Buger

I did some acceleration estimates for different weights using the US spec gearing ratios. This may give some idea of how the final weight will affect acceleration times.

SPECS:
hp: ............... 250 @ 8500
torque: ........... 159 @ 7500
redline: .......... 9000 rpm
wheels: ........... 225/45R18
driver weight: .... 165 lbs
fuel weight: ...... 30 lbs
drag coeff: ....... .30
Air temp: ......... 65 degrees F

curb weight:........ 2950 lbs :
0-60: ........... 6.03 seconds
1/4: ............. 14.48 @ 98.13 MPH

curb weight:........ 2975 lbs :
0-60: ........... 6.07 seconds
1/4: ............. 14.52 @ 97.92 MPH

curb weight:........ 3000 lbs :
0-60: ........... 6.11 seconds
1/4: ............. 14.56 @ 97.72 MPH

curb weight:........ 3025 lbs :
0-60: ........... 6.15 seconds
1/4: ............. 14.59 @ 97.54 MPH

Brian

Buger

Hi Cbj,

Thanks for the compliment. The S2000 is a production car so the EPA fuel economy figures can be seen at http://www.fueleconomy.gov/feg/compx2003f.jsp

1. The S2000 gets 20 mpg city / 26 mpg highway in the standardized test that the EPA uses for all cars. I previously estimated that the RX-8 will get 19 mpg city / 27 mpg highway which is a little higher than the 1.3L RX-7s from about 15 years ago had 17/25 EPA figures. The figures that the magazines put out have been wildly varying. We've heard as low as 20/24 to as high as 20/30 (from Car&Driver). It would be something if the RX-8 can beat the S2000 in fuel economy using lower compression ratios and a heavier car wouldn't it?

2. I'm not worried about the reliability issue although you are right that nobody will really know until the RX-8 has been out for awhile. One of Mazda's main goals was to erase the memory of the reliability problems of the last twin-turbo rotary. I think that is why they decided to go with a compression ratio of 10:1. A higher compression ratio would have increased power and fuel economy but perhaps Mazda will do this for a future model. By comparison, I think the S2000 has something like a 11.1:1 compression ratio. I've heard that BMW has had many problems with their M3 E46 engine (11.5:1 compression ratio) but I assume the S2000 has been quite reliable? (as Hondas usually are )

3. I think the dealer mechanical support is a valid concern. If something does go wrong, you want somebody who really knows what they're doing to work on it. There are many independent "rotary specialists" that are out there because of the demand for them though. Still, the RX-8 will probably have the same 4 year/50,000 mile warranty that Mazda is offering for their other cars so we will have to hope that Mazda makes sure that it's mechanics are competent with the rotary.

I think that many previous S2000 owners would be considering the RX-8. Do you agree? Most of us have to give in to practicality when we have a family and I would think that many S2000 owners would hate to go from their 8900 rpm revving car to some practical car that could only rev to 7500 or something.

Brian

cbj

Brian,

1. You're right on the 20/26 figure for the S2000. I don't know why 20/28 stuck in my head. I've seen the estimates for the RX-8 all over the board in the magazines as well.

2. Having owned a rotary before I'm not particularly worried about the reliability either. I do think Mazda will have to battle the rotaries= unreliable/inefficient perception some people have.

3. Dealer support is my only real concern. It's bad enough with an S2000 because some dealerships don't do much work on them, but at least it's still a piston engine. The learning curve for Mazda mechanics and the Renesis would be a little steeper. At least that is my gut reaction.

As for S2000 owners looking at the RX-8, I would thinkthere would be a fair number. It really depends on the person. If someone has to replace/add to the S2000 and really likes a good handling, high-reving, high involvement car - then it's a natural fit. Some folks end up wanting more luxury and the lower involvement of a higher torque engine and don't mind giving up a little in handing and adding a few pounds- they will probably end up with BMW 330/M3 or an Infiniti G35. Another group are those owners that might want something for the winter or prefer the upgradability of OEM FI and will look towards the Sti or the Evo.

The S2000 engine has been pretty reliable. There were some issues with a few of the early '99 cars. Also Honda just changed the design on the oil bolts and has done a recall for Europe but not for North America. The only thing I've had to do with mine was a recall for the spark plugs. The plugs were working loose on some cars so they changed the washers and the torque specs.

Most of the other problems with the motor seem to be caused by owner error. The predominate problem is overreving the engine by skipping gears when downshifting. i. e.5 to 2 at 80mph.

eccles

Unless they've updated CarTest since I last tinkered with it, I think its results are likely to be a little conservative for the RX-8. If you can still only enter peak HP, peak torque and rev limit, there's no way to tell it about the flat torque curve of the Renesis. With just those three numbers to go on, I'll wager it extrapolates a curve that looks more like a VTEC Integra.

The flatter curve of the Renesis should result in less power drop between gears.

Buger

Hi Eccles,

I used Cartest2000 which does allow you to enter specific parameters for customized torque curves. Both the RX-8 torque curve and the S2000 torque curve that I posted a picture of were from customized parameters that I created.

Of course Cartest2000 also uses profiles to create an approximation of torque curves based on peak hp, torque values adn redline if the specific curve isn't entered in. Their profiles actually do a very good job of estimating performance of the actual curves.

Brian

revhappy

The EPA fuel economy estimates are often way off in the real world. A lot of the competing cars (with larger displacement engines/forced induction) with the S2000 have similar EPA estimates, but always seem to do much less in moderate/normal driving. For example, the Lancer Evolution has EPA estmates of 18/26 or 1 MPG combined city/highway less than an S2000. I seriously doubt that will hold true in the real world under NORMAL driving. I've seen many posts on s2ki.com with people getting 30 or more MPG on long trips doing moderate driving (not grandma driving!). Of course, some of these owners get like 7 MPG at the track.:D As for emissions, I remember Buger posted an interesting post about the renesis and the rx8s potential classification under current and new emissions rules. I think itd be interesting how the RX8 compares with some competing vehicles.

As for the reliability, I do think the Renesis will be fine, but I think it needs to build up a good reputation for people to percieve it as such. I think this will take some time and the F20C or similar engines should have the edge for awhile (at least in peoples perceptions).

I agree totally with the lack of rotary mechanics being a real concern. As someone who has had engine troubles far from home (in a pretty rural area), I think it is a valid point.

I think this is the 4th year of production for the S2000. I believe it is one of the last of the Honda's current models using the older generation of VTEC, but I could be wrong. I think all of their models (including the S2000 or some future performance car) are supposed to switch to I-VTEC.

The I-VTEC system offers better mid-range power than the VTEC system currently used in the S2000. I posted sometime back that the RSX-S torque curve was almost identical to the RX8's (albeit with only a peak of 142 lbs-ft with a redline of 7900). Obviously, this engine isn't tuned to to the level of the S2000 (they are both 2.0 liter 4 bangers). EVO magazine had a couple of articles about the RSX Type R (available only in Japan currently ) , which is about midway in terms of performance between the RSX-S and the S2000 (220 HP with a redline of 8500) and they seemed to indicate it had much more mid-range power than the integra type r (which was very similar in nature to the F20C). Ironically, they liked the ITR's split personality (i.e. high end power) better (even though the RSX-R put up better numbers)!

I think the Renesis and Honda's VTEC/I-VTEC or similar variant will lie within the best lightweight, low-moderately priced sports cars in the near future (say next 10 years). Though, I tend to think the Renesis has more potential for performance. I guess time will tell.

That's my Opinion, But You're Welcome To It!

revhappy

Another thing regarding the S2000, I have always thought that convertibles tend to weigh more than coupes..and also tend to be an inferior design (as compared to coupes) for handling (less stiff suspension).

Oh, one other advantage to the F20C as opposed to the renesis, is it can be turbocharged...giving you mid 13s in the 1/4 mile. Though, I'd keep either engine naturally aspirited.