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Feel of a Rotary Engine
I've heard a bunch of people say you have to feel a rotary engine to understand. I've never had the opportunity to drive an Rx7. So what's the big deal? Is there a noticable diffence between the feel of a piston engine vs. a rotary? How does it feel different?
The only thing I can think of is that most of power comes in a higher RPM right? But that's not really any different than a lot of 4 cyl VTEC/VVT engines. |
from my experience... the Rotary doesn't vibrate as much, has a nicer sound, and has no torque.
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how do you mean it has no torque?
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Sound
Speaking of sound...does anybody know of a site with samples of what a rotary engine sounds like? I've done some searches and visited the sites that came up in the results, but the samples I found weren't very good.
The sound of the engine is important to me when considering a car purchase, and I've been told rotaries have a very distinctive note that I'm curious to hear. Any suggestions of sites I could visit would be appreciated. |
There is no real powerband "hit"(turbos excluded). It spins like an electric motor to the structural limits of the rotors and housings themselves. The feel(vibration or lack of?) is similar to most modern V-6 engines, only it never falls off the powerband. As the rpm climb, the more efficient and more power it makes, with only 3 moving parts. It loves and lives to rev. :)
787b This is the 1991 LeMans winning 4-rotor taking it easy at Laguna Seca. Some Dyno-runs can be found here. |
Sounds cool. Almost like a motor cycle.
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by no torque, I mean that there is little power when the engine is under 4,000 RPMs. The engine isn't highly responsive until the engine revs are up high... as opposed to my Impreza now, with a 2.5L boxer 4, the thing can be at 2,000RPMs, and have almost as much power as there is at 5,000RPMs
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I thought that the R&T article mentioned that 90% of maximum engine torque would be available at 3250 RPM. If that is the case, I do not see torque being an issue.
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that may be true...but on my older RX-7, that sure wasn't the case.
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Hey Toadman
I'm trying to attach a file like you did for the sound and dyno tests, but can't figure out how to do it. I have an RX-7 dyno test that will blow you mind. Can I email it to you, and have you post it on the forum?
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Originally posted by DANNER Sounds cool. Almost like a motor cycle. |
No it's not. The LeMans car - even in qualifying trim - had a max redline of about 7500rpm with a race redline of either 6750 or 7000 (cant remember) it did not rev high, I imagine because of ecc. shaft flex. It sounds cool because:
a) It's a 4 rotor b) It's a PP -pete |
This is taken from a very good article on the 787B here ...
http://dev.roadandtrack.com/images/r...mazda_787b.htm "At Le Mans, an 8500-rpm limit was used during the race and up to 9000 rpm was allowed for qualifying" There is some excellent technical information here for anyone interested in real details about the engine. http://www.mymazdarotary.com/mazda_r...paper_html.htm |
Feels is like a turbine. Although I've never personally felt an actual turbine, it's the first thought that crossed my mind when I drove on. Fairly vibration free with smooth power delivery.
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Originally posted by ZoomZoom I thought that the R&T article mentioned that 90% of maximum engine torque would be available at 3250 RPM. If that is the case, I do not see torque being an issue. |
Originally posted by rpm_pwr No it's not. The LeMans car - even in qualifying trim - had a max redline of about 7500rpm with a race redline of either 6750 or 7000 (cant remember) it did not rev high, I imagine because of ecc. shaft flex. It sounds cool because: a) It's a 4 rotor b) It's a PP -pete |
Driving a Rotary is like nothing else. Smooth as ice the car just goes where you want it, hard to explain. Its like having a spaceship engine.
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it better have lots of torque...
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LOTS of torque? You might wanna look at a V8....
While this rotary promises to have good midrange punch, rotaries have never been what you would call "torquey." |
Rotaries are revvers. If you want to short-shift it like a Mustang GT or something, you'll be disappointed with the performance. Torque is supposed to be around 155 ft lb., 90% available between 3000 rpm - redline.
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well now i look like a dumbass.
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Originally posted by eelkmoore it better have lots of torque... -pete As probably the only person on the forum with a dual-axis accelerometer kicking around I think I should clear a few things up that some people (buger etc) have touched on: 1) Your accelaration graph is *PROPORTIONAL* to your torque graph for in gear acceleration 2) The proportionality constant is = (tyre radius * gear reduction) / mass 3) The important factor here is gear reduction (diff ratio * current gear ratio). In other words you can double your acceleration (wind resistance ignored) by doubling you diff ratio. But by doing this you can detract from the usability of the car by reducing the max speeds in each gear. Now here is the important bit: ENGINES WITH HIGHER OPERATING RANGES CAN USE HIGHER RATIO DIFFERENTIALS FOR THE SAME AMOUNT OF DRIVABILITY. THIS MULTIPLICATION EFFECT GIVES MORE GROSS TORQUE AT THE REAR WHEELS GIVING MORE ACCELERATION END OF STORY. 4) Torque spread only affects how wide you can spread the gear ratios. It does not matter where in the RPM range the spread is because this can be traded with diff ratios rather it is the RPM range that affects how close you can make the ratios. So a car with power from 5000rpm to 8000rpm can have ratios just as wide as a car with power from 2500 to 5500 with the added advantage that it can run a higher diff ratio to increase acceleration. 5) so say car a makes 200lb.ft from 3000 to 6000 with a 4.11 rear (FD?) car B makes 150lb.ft from 5500 to 8500 with a 5.82 rear (rx8?) car a has 822rw lb.ft GROSS car b has 873rw lb.ft GROSS but here's the catch - both cars have identical speeds in each gear! It gets better the higher torque numbers give a higher top speed as well! 6) With all this messing around with mulitpliers, dividers, NET torque gross torue isn't there an easier way? Yes. It's the often neglected POWER curve. Power at the flywheel = power at the wheels - gear losses. So you can simply overlay two RWHP graphs with shift points marked to figure out which will accelerate harder. It's a lot easier. That's why we can't bench race the rx-8 yet - because there is no power graph yet. Although if the torque spread stays that good then it will be ONLY the diff ratio stopping the rx-8 from being an FD rx-7 killer. |
The feel of a rotary is like no other. First there is no vibration, in my old 1st gen RX, when it was properly tuned, you could hardly tell when the engine was on. There is no vibration whatsoever. As far as torque, I never felt like it lacked it. By no means is it a big block V8 from Detroit, but it has enough. Also, Mazda always does a great job with the gearing.
I cannot wait to get one..... |
uuuhhh what he said...
jj We will just have to drive it. |
This is an old thread that should start up again now that we all know what they feel like. I want to know your opinions on how they feel to you in your own words.
To me its like a Singer sewing machine. |
Ducati spinning up.
it's a 1.3l for goodness sakes.... how much torque does a 1.3l piston engine pushes out? |
Holy crap is this an old thread. At least we know one person uses the search around here. Sheesh. However, on topic...the main feeling that I get from my 8 is the endless power curve. In a piston engine you can feel it sorta die off after 5K RPM...in an 8 you are just getting started at 7.5K.
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4.5 years old!!! Damn, this is an epic thread bump.
As for how it feels, I would have to say smooth is the best description. |
I love reliving the past so I look for retro threads and start them up again.
One of my bizarre hobbies. |
smooth as thai silk
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Didn't read all the posts but if you are listening to sound clips, keep in mind many cars have modded exhausts so not the stock sound.
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"feels like it is running on double cream" - Jeremy Clarkson
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^^^thatīs a VERY good definition.
And apart from that, such an small and light engine allows an almost midship placement with a very low yaw inertia moment meaning extraordinay handling. jird20 |
like flying close to the ground.
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Power comes on smoothly like being pushed forward by a giant wave.
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Originally Posted by Socket7
(Post 2200333)
Power comes on smoothly like being pushed forward by a giant wave.
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I love the way the rotary makes the suction sound sounds as it drains my gas tank as if I was driving a an M1 tank.
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dare we say . .
it has the smooth power delivery of an electric engine |
Originally Posted by Raptor75
(Post 2200442)
I love the way the rotary makes the suction sound sounds as it drains my gas tank as if I was driving a an M1 tank.
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this doesn't have to do with "sound", more "feel", i let a friend drive it and he kept shifting at like 7k, i had to "coach" him, even though he was older and had driven a lot of cars and bikes for that matter, to hold on to each gear! he loved it, he just couldn't believe it revved so high - he also said he felt it had more torque than he thought it would...
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Originally Posted by 2tone
(Post 2200480)
this doesn't have to do with "sound", more "feel", i let a friend drive it and he kept shifting at like 7k, i had to "coach" him, even though he was older and had driven a lot of cars and bikes for that matter, to hold on to each gear! he loved it, he just couldn't believe it revved so high - he also said he felt it had more torque than he thought it would...
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This is no small point. The 'feel' is why so many people criticize the 8 as being 'slow'. For some it doesn't give their butt-dyno that sense of acceleration that they equate with speed. Of course most of us know otherwise.
To me it feels like a silky smooth turbine (well, above idle anyways). |
it feels like a car
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Its such a smooth sounding/feeling motor. Just sitting in the car in neutral you feel no shake or vibration. The RX-8 is my first rotary, though I did get to ride in my friends RX-7 which was a little rougher feeling (but the motor was rebuilt).
Jeremy Clarkson says it best... "It doesn't feel likes its running on anything as course and vulgar as petrol. Feels like its running on double cream!" |
The OP last posted on 4/02. I hope he got the answer to his question...:-/
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To be honest, I feel like the uniqueness of the rotary is the feeling you get mentally. Its just the adrenaline rush of a blender like sound and watching your tach climb to 9K as youre taking a corner at 62 mph in second!!! Thats the unique feel of the rotary to me, otherwise it just feels like a lack of torque :lol:
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NA its like dropping off the top of the big hill on the roller coaster- the speed just keeps building and building
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Originally Posted by Juice
(Post 2200149)
4.5 years old!!! Damn, this is an epic thread bump.
As for how it feels, I would have to say smooth is the best description. I'm The "EPIC THREAD BUMPER" |
i was here lurking and reading it in its original posting
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LOL, I don't see anything wrong with it!
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