How Rotary Engines Work

Tominator

Diamond Member
Oct 9, 1999
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The rotary was neat back when Mazda first produced it...that site just makes it easy to understand! Great link!
 

Killbat

Diamond Member
Jan 9, 2000
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I've always wondered how exactly those things cycle. That animation REALLY helps.
 

Cooltech2k

Banned
Feb 9, 2001
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hahahaha the guy sitting next to me at work yesterday wanted to know how they worked & I Directed him to that sight...
 

rufruf44

Platinum Member
May 8, 2001
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Wow, Mazda going to relaunch the rotary engine type.....Always loved those RX-7!!!!
 

8602081

Banned
Jul 10, 2000
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I used to own 1990 RX-7. I miss it, had to get rid of it, because the engine locked up on me. That sucker could move. The size of the engine was only 1.3 liter, but it had much higher rpm and runs smoother.
 

NFS4

No Lifer
Oct 9, 1999
72,636
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<< had to get rid of it, because the engine locked up on me. >>


Looking at how the rotor on the second page/first pic is worn down I can see why..not unless it is supposed to look like that on each side:Q
 

geno

Lifer
Dec 26, 1999
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I wish Mazda would produce something a little more potent. 250/260HP isn't a huge deal, even in a car that weighs less than 3000lbs. I don't know what effect increasing the displacement on a rotary engine, but I wish they'd up the boost, add a rotor, or do something to make this car more of a competitor (at least in the american market). Well, it's a little too late for wishing now :)
 

ThisIsMatt

Banned
Aug 4, 2000
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<<

<< had to get rid of it, because the engine locked up on me. >>


Looking at how the rotor on the second page/first pic is worn down I can see why
>>

How so?

I already knew how they worked, but what I don't know (and that I didn't notice in the article) is how exactly they are lubricated? Looks to me like it would burn oil all the time (moreso than a piston engine)...
 

NFS4

No Lifer
Oct 9, 1999
72,636
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<< I wish Mazda would produce something a little more potent. 250/260HP isn't a huge deal, even in a car that weighs less than 3000lbs. I don't know what effect increasing the displacement on a rotary engine, but I wish they'd up the boost, add a rotor, or do something to make this car more of a competitor (at least in the american market). Well, it's a little too late for wishing now :) >>


I'm not sure that I understand what you mean. The 3rd-gen RX7 was turbocharged and had 255HP. It did 0-60 in 5.0 seconds. Pretty damn fast if you ask me.
 

frizzlefry

Golden Member
May 14, 2001
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Don't you just love that name? Wankel Rotary Engine..... :D

The RX7 was an awesome car (still is IMO). Can't wait to see the RX8. :)

Great info BTW.
 

geno

Lifer
Dec 26, 1999
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<< I'm not sure that I understand what you mean. The 3rd-gen RX7 was turbocharged and had 255HP. It did 0-60 in 5.0 seconds. Pretty damn fast if you ask me. >>


Yeah, but overall it came up short in comparison to the Supra and the 300ZX when it came to power...Again, I realize the power to weight ratio advantage, but I normally see stock RX7s running very high 13's while I normally see Supras in the low 13s.
 

NFS4

No Lifer
Oct 9, 1999
72,636
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<<

<< I'm not sure that I understand what you mean. The 3rd-gen RX7 was turbocharged and had 255HP. It did 0-60 in 5.0 seconds. Pretty damn fast if you ask me. >>


Yeah, but overall it came up short in comparison to the Supra and the 300ZX when it came to power...Again, I realize the power to weight ratio advantage, but I normally see stock RX7s running very high 13's while I normally see Supras in the low 13s.
>>


Ummm, high 13's, low 13's...who cares????!!!:p Do you only care about straightline performance?? That doesn't make a car. If I recall correctly, the Supra was a heavy mofo and the RX7 will soundly smack its a$$ around the twisties.
 

geno

Lifer
Dec 26, 1999
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Yea, the Supra is a bit heavy on the scales - but if you wanna bring track performance into this, you'd better hope there's no straightaways on that track :p The Supra can handle, but I'm sure it's not up to snuff with what the RX7 can do in the corners. And there's a huge difference between high 13's and low 13's :)
 

rbV5

Lifer
Dec 10, 2000
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<< 250/260HP isn't a huge deal >>



In 1.3 liter, thats a big deal cmon. Christ I remember my buddy had an rx3 with nothing more than a Kendig carburator and a header and would run head to head with Big block chevy's in the 1/4 mile. Dropping that clutch at 12,000rpm and going through the 5 speed like a honda CR250, OMG that brings back memories. It used to be his moms car, and other than air cleaner sticking through the hood, and the slicks in the back, still looked like it. A real crowd pleaser at PIR.

Anyone remember Rising Sun Motors? Now they could get those rice burners moving!

Edit: yea, I miss my '79 RX7 <sniff>
 

geno

Lifer
Dec 26, 1999
25,074
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What I was saying is, for something that was supposed to be competing with the Supra, it isn't much, even with it's 2800lb frame.
 

NFS4

No Lifer
Oct 9, 1999
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<< Yea, the Supra is a bit heavy on the scales - but if you wanna bring track performance into this, you'd better hope there's no straightaways on that track :p The Supra can handle, but I'm sure it's not up to snuff with what the RX7 can do in the corners. And there's a huge difference between high 13's and low 13's :) >>


But if you're on a road course, the RX7 would more than make up for the difference in the 1/4 mile on the twisty stuff. I just don't get the point of drag racing anyway...pretty pointless to me. A road course actually works the entire car.

Anyway:

Mazda RX7 -- 2858 lbs
Toyota Supra Turbo -- 3515 lbs
 

natto fire

Diamond Member
Jan 4, 2000
7,117
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cool article. but thisismatt has a point that it doesn't exactly explain lubrication (or did i miss that?) I really do think rotary engines are sweet. and now that Renesis figured out how to make them burn more cleanly there's just another advantage. (I believe Renesis put the exhaust port on the side and did something else but i have the article in Road&amp;track)


EDIT: does the RX-7 have a multilink suspension? Well i have driven three markIII supras, and they all handled like the weighed 2000 lbs. I was simply stunned that a car that heavy could handle so well. I really think that the MarkIII Supra was way ahead of it's time with the styling and amenties in what was supposed to be a &quot;sports&quot; car. And even though I think Rotary engines are great I think the 7M-GTE is even better. This is just personal preference of course. Now if we really want to talk fourth generation Supra, the car was reduced to 3200 pounds for the turbo, which made 320 hp@5,600 rpm; 315 lb.-ft. @ 4,000 rpm.
 

rbV5

Lifer
Dec 10, 2000
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<< I just don't get the point of drag racing anyway...pretty pointless to me. A road course actually works the entire car. >>



True, true, and tests driver skill for sure, but drag racing certainly holds a place in my heart for sure. Drag racing to me is a little like overclocking your cpu and getting the most you can out of it. Its more of a test of mechanical skill I guess.
 

mAdD INDIAN

Diamond Member
Oct 11, 1999
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From what I have understood and read, the Supra will keep up with the RX-7 on the road course. The Supra ain't no slouch either when it comes to handling, regardless of its weight. Same goes for the 300ZX.
 

NFS4

No Lifer
Oct 9, 1999
72,636
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<< This is just personal preference of course. Now if we really want to talk fourth generation Supra, the car was reduced to 3200 pounds for the turbo, which made 320 hp@5,600 rpm; 315 lb.-ft. @ 4,000 rpm. >>



While the HP/Torque number are correct, the lowest weight for a '98 manual Turbo is 3515. The base model (non-turbo version) weighs 3265.
 

geno

Lifer
Dec 26, 1999
25,074
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<< But if you're on a road course, the RX7 would more than make up for the difference in the 1/4 mile on the twisty stuff. I just don't get the point of drag racing anyway...pretty pointless to me. A road course actually works the entire car. >>


Yeah but how often do you get to go through the &quot;twisty stuff&quot; from day to day? I know I can work the engine to it's fullest whenever I accelerate from say, a red light, onto a highway, etc. But I don't see how a great suspension can be pushed out on the street.
 

NFS4

No Lifer
Oct 9, 1999
72,636
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<< Yeah but how often do you get to go through the &quot;twisty stuff&quot; from day to day? I know I can work the engine to it's fullest whenever I accelerate from say, a red light, onto a highway, etc. But I don't see how a great suspension can be pushed out on the street. >>


Not everyone lives in the city. Backroads are very common around here ;) And how often do you gun 0-60 in 5.0 seconds or rip 13 second 1/4 miles in your car on a daily basis. Probably not too often unless you're in &quot;The Fast and the Furious&quot; bunch.
 

geno

Lifer
Dec 26, 1999
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<< Not everyone lives in the city. Backroads are very common around here ;) >>


Forgot about that - you have a good point :)



<< And how often do you gun 0-60 in 5.0 seconds or rip 13 second 1/4 miles in your car on a daily basis >>


Actually, pretty often - not that I push the car to its limits when it comes to acceleration, but every day I like to unwind the engine out to like 4500RPMs at like 75% throttle to get a nice rush :) then on days when I really wanna get going, it's 6000RPM for me @ WOT, that's when I get to see my real 0-60 time :D
 

yakko

Lifer
Apr 18, 2000
25,455
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<< The rotary was neat back when Mazda first produced it...that site just makes it easy to understand! Great link! >>

Nowhere near as neat as the original design that crazy german Wankel came up with. It would do 25,000 rpm and was extremely quiet. The main reason it did not get produced was that to replace the spark plugs you had to take apart the whole engine.

I once saw a book on the history of the rotary engine and it went into much more detail than that website. It even had pictures of the Corvette that was going to have a rotary if Chevrolet had kept the program.