Rx-7
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You are currently reading a thread in /o/ - Auto
You are currently reading a thread in /o/ - Auto
What do you guys think about rx-7's and rotary engines?
bretty gud
JUNK
>>14796084
1 8 0 °
8
0
°
RX-7=good
rotary=bad
>>14796084
*brapbrapbrapbrap*
*apex seals broken*
>>14796084
The FC is actually one of the best cars for the money.
I've owned several. A few over 200k miles on original engine. Never managed to pop an apex seal. Did have one with a bad coolant seal and took a day to replace it.
Very easy to work on. NAs are a bit slow nowadays. But can be easily brought down to 2400lbs or less depending on how far you wanna go.
They respond well to mods.
Don't let these idiots fool you into thinking they are unreliable. I daily'd one for 7 years with only needing a starter replaced.
i love mine
kinda hard to daily tho
2fun
Had an FB for 3 years, loved that sound
>>14796114
How many empty bottles of oil did you have in your hatch? Did you have a Jerry can for premixing you busted piece of shit?
>>14796084
All my knowledge of the rotary engine has come from /o/ so it's a mix of bullshit with a little bit of truth.
Aren't the most reliable, have potential for power, may burn a lot of oil.
They are sexy as fuck though.
>>14796145
Why you so mad?
I never premixed.
I carried 1qt of oil just in case but only ever used it on road trips.
>>14796084
Torqueless useless meme shit.
god why is everybody so salty when it comes to rotaries
>waste gas
>make lots of power
>rev high
>scare small children and the EPA
>win races (787B)
>triangles
I just don't understand whats not to like
>>14796203
>Torqueless
Wut?
This is simply not true
>>14796185
You should have premixed tho
>>14796244
Why? Was on good compression over 200k miles. Was running fine when I sold it.
>>14796203
flat torque curve, high redline and high gearing
Low end torque is for people who slow down on turns anyway, or don't know how to revmatch/heel-toe
>>14796212
Because practically nobody knows how they work.
So instead of trying to understand them everybody just spews /o/ memes in attempt to troll rotary guys.
>>14796248
That may be true, but it would have been in better internal condition
>>14796258
Meh.
>>14796230
but it is prettz true though. rotaries make torque waz too high in the rev range to be useful.
but, honestlz, whoo buzs a rotarz and doesnt rev the cunt out of it_
>>14796103
>non-spread port exhaust & intake
>shitty dual plane manifold
>iron block
>probably iron heads too
2/10
>>14796244
>>14796145
Dedicated oil injection > premix
>>14796203
It provides power using rotational force, therefore, it has torque. Anything else can be solves with a gearbox.
>>14796254
pretty much
From an engineering perspective, they are very interesting and in my opinion have alot of potential. They're kind of like a cross between a jet engine and a piston engine in that they conserve their rotating mass well.
Really the only reason they have so many problems is because of the combustion chamber design. When at the rotary equivalent of top dead center like in a piston engine, the intake mixture is long and thin as it's squished against one side of the rotor. This makes it harder to ignite as the flame front of the ignition explosion has to travel all the way up this long thin sliver of gas. When at high RPM, the rotor is already moving away too fast to complete combustion and some fuel is still left in the exhaust charge. I think through the use of sequential ignition systems and variable geometry exhaust ports, this could be solved.
>>14796203
dont reply to this butthurt europoor
>>14796293
Adding ignition points would help too.
>>14796293
It also doesn't help that piston engines have enjoyed vast amounts of research and development from every engine manufacturer on earth, resulting in a very refined and mature state of technology. The reciprocating eninges of today, especially diesels, are almost unrecognisable compared to their equivents 10/15 years ago, in terms of NVH, fuel economy, specific power, reliability. If rotary engines or other powertrain architrectures had the same amount of devlopment time and money spent on them, they wouldn't suffer from the reliability issues that are associated with them.
The potential will never be realised, because it is difficult and expensive to do so; for reciprocating engines, most of the potential of the design has aleady been realised.
Having said that, the lack of flexibilty for combustion chamber design does not help, especially with modern emissions regs and a focus on efficient, low-emission combustion.
And while it may help with emissions, I never want to see a rotary engine with Miller valve timing. So maybe it is best that it lies dead and fondly remembered while IC egines of all kinds are slowly neutered.
>>14796269
Still getting used to a German keyboard, anon?
I feel Doritos are for eating, and so does the 13b apparently...
>>14796293
why doesn't someone redesign it?
>>14797681
or even better, a very eccentric shaft
>>14797681
or even better, a very eccentric shaft>>14797688
>>14796473
>Having said that, the lack of flexibilty for combustion chamber design does not help, especially with modern emissions regs and a focus on efficient, low-emission combustion.
That's not true. There is flexibility in changing the combustion chamber.
Yes when the rotor face is against the side at the ignition point, you have a gap on both the leading and trailing side where the fuel-air mixture is compressed.
And due to the spark plugs being a bit regressed inward and j-plugs not being possible, it means the combustion chamber has to be long and shallow.
However, there are a few possibilities.
One is you combustion later, when the trailing rotor edge is flat against the chamber, and there is more opening on the leading edge instead of a small amount both sides.
Currently the combustion is when it's flatly lined up so there is a minimal amount
The problem with this is that it only works at lower RPM because there isn't enough time for the flame to fuel to burn and torque against the rotor before the exhaust stroke happens.
The other is that you have laser ignition, which allows a deeper and more round combustion "chamber" shape. Although you still have the gaps on the leading and trailing sides, you can have more depth in the combustion chamber where the air-fuel mixture is ignited in the center and can have a greater amount of compressed mixture there instead of on the sides.
You also then have the possibility of injecting fuel on the compression stroke right into the chamber, so there is less compressed air-fuel on the sides.
Currently if you ignite fuel-air mixture early, well then it's pushing at the rotor at suboptimal angle and doesn't torque as much. But this increases efficiency and torque at higher RPM as the rotor spins a lot before the flame starts propagating a lot, but is worse at low RPM.
>>14797806
If I understand correctly, mazda could implement a system where at low RPM's the ECU uses a late ignition and at higher rpm's uses an early ignition.
The laser ignition sounds pretty neat and all, but if that doesn't work out then I don't see why 3 or more spark plugs couldn't. It's been done before on R26B engines.
babby rotors when?
>>14796212
>scare children and epa
Underrated post
Love them. My brother had an RX-7 and let me drive it sometimes. Torqueless, but sooo very smooth and revvy.
I just wish they could do something about the fuel and oil consumption, as well as the engine heat. I've heard rumors that Mazda may be on to something recently, but it will require something revolutionary to match a piston engine.
I fear it will be a footnote in history.
>>14797911
If you had 3 spark plugs, yeah they could.
On the Renesis and others they had 2 at the center, spaced a little.
On the 787B they had a 3rd which was far-trailing. That's how they get the fuel to burn at high RPMs.
On the latest Mazda patent they have 1 in the center, and 1 where the far-trailing was at the 787B, for 2 total.
I would figure they would just put a third on the far-leading side to increase efficiency at low RPM.
There is a problem, though, that more spark plugs makes more openings on the side housing where air/fuel mixture and exhaust escape into different stages and makes compression harder.
And see, that's another of the big problems with them, having that gap for spark plugs.
Unless they use lasers with a lens that is flush against the rotor wall...
Or even not a laser, but some sort of flat surface that can seal the rotor wall but also ignite the fuel.
This is also why compression ignition has be talked about for rotaries. With compression ignition you get more uniform combustion and without the openings spark plugs make.
Mazda does have to do something about the combustion chamber shape and the ignition to get a big leap forward. Just changing the port and header shapes isn't going to do it.
The third issue is that there is a lot of surface area that adsorbs heat instead of turning that heat into mechanical energy. That's something that can be solved with materials, theoretically, or from a system that draws heat from the engine block and turns it into electrical energy (which Mazda has been working on for the 3rd generation of Skyactiv, but won't be here until like 2022-2025)
Theoretically though, there is no reason why a rotary couldn't be more efficient than a piston engine. It could even potentially be more efficient. There are massive problems with the old designs that aren't much different than the 70s ones.
>>14796269
No, they have generally flat torque curves unless turboed
>>14798094
>Rotary with electrical waste heat recovery
>electric motor for torque at low revs
>rotary engine for glorious silky high-rev performance
Please build it, Mazda.
I sold my 91 rx7 convertible for a 99 mx5.
All the reasons mentioned above are valid. I averaged around 14mpg and the car barely made 150hp. I made the mistake of not letting it warm up properly on a cold day before I shut it off and it sat flooded in my driveway for a week before I had to pull all the plugs and dry crank it, then add trans fluid to the CC to bump compression up enough to get it running.
The miata is a much better car than the FC is, but id give my left nut for a clean FD.
fun but not practical. rotary vehicles are for hobbyists, and there's nothing wrong with that.
>>14799260
They have said that the FG, the one after this next one, will likely be a rotary-electric hybrid.
I think the waste heat recovery is going to be too heavy for a sportscar, though.
Well maybe not. Depends on the system.
I'm honestly surprised it doesn't look like they're not going with a hybrid electric turbocharger for the new one. Using an electric motor on the turbo to drive it on low RPMS. Get higher compression and fuel stratification at low RPMs to increase efficiency. And instead of a wastegate use that excess to charge the battery.
Or maybe they will, and those plans aren't leaked yet.
I love rotaries and mazdas, every related thread these days seems to get shitted up by memetards though.
>>14796084
I think they're fucking rad and the FD RX-7 has given me a goal to work hard towards owning.
>>14799392
>The miata is a much better car than the FC
Not really. It's cool that you enjoy it more.
I've owned both and the miata is much much worse IMO.
>>14799447
I read some aussie thing a few days ago with an anonymous source at mazda claiming they've got 450 hp with two turbochargers, one of which is supposed to be an electric hybrid turbo. So, excite! I guess
>>14801186
*on the skyactivR/16X
>>14801186
found it: http://www.motoring.com.au/new-mazda-rx-secrets-revealed-100186/
could be shameless gossip, but it gives me hope.
>>14801186
I sooooo doubt it's twin turbo. That's just idiotic this day in age.
When is the last time a twin turbo car has been made? I can't think of any productoin now.
Turbos are better now, and there's other systems like variable geometry turbos.
The VG turbos on the 911s can handle the heat from a rotary fine.
Australian rumors are always fucking wrong, too.
I'd expect a single turbo with some sort of system to reduce lag like on the CX-9, a VG turbo, or a hybrid-electric turbo.
>>14801186
will be good when someone rips all that extra shit off, pports the fuck out of it and makes 600hp
It's like we havnt had this thread a million times before.
>>14801221
>Australian rumors are always fucking wrong, too.
>>14801220
Judging by the engine patent, I am guessing it'll be transaxle, though. That part looks right.
And sub 1400kg?... lol it'll be under 1300kg. Likely under 1250kg, even.
And 450hp? No way. This car is going to be targeted as a much cheaper Cayman GT or GTS at best. Maybe Cayman GT4 with an expensive optional package.
There is so much nonsense there I can't believe they got anything right.
>>14801226
I wouldn't be surprised if the new one is 300-320 HP, 275lb-ft of torque, and makes over 400hp just from taking out the emissions shit.
>>14801221
lol idk dude rotaries spit out some pretty damn hot exhaust fumes for a VGT.
>>14801221
at the very least, mazda's basically confirmed that the new set-up will be turbo'd, I guess we'll learn more whenever mazda deigns to tell us.
>>14801220
And hybrid-electric?
No, they already 100% unequivocally confirmed it won't be hybrid.
>>14801248
Rotaries put out about 1700-2000F. Over 1800 is just if you run it rich.
Porsche VG turbos handle up to 1800. And there's ways to cool it quite a bit before it reaches the turbo.
They can absolutely handle rotary exhaust.
>>14801261
Yeah I think they did confirm turbo recently but I don't recall the source.
On their patent they talk a lot about a turbo. Not sure how recent that patent was.
>>14801265
source was mazda's cheif of design or something. Their higher-ups have been saying similar things confirming turbo in interviews, too.
>and hybrid-electric
They 100% confirmed no hybrid, but I was talking electric turbo (I've heard it called hybrid-electric turbo by others)
>>14796269
Yet rotaries make peak torque very early and hold it
13brew makes 90% of its torque at 3000rpm
>>14796203
Buttmad europoor who can't afford insurance or petrol detected :^)
>>14801285
Oh right the article says it'll be a hybrid-electric turbocharger and not hybrid-electric drivetrain.
That might make sense and I'd actually like having the i-eloop system if it doesn't add more than like 40lb.
>>14801285
>electric turbo
As in the turbo is run of an electric motor and not exhaust gases?
>>14801374
Hybrid, so both.
At low RPM, an electric motor drives the compressor to give boost at low RPM like a supercharger and keeps it from lagging.
And it recovers RPM off what would normally be the wastegate. Like regenerative breaking but for the turbine.
Keeps the boost both steady at all rev ranges and more efficient. An upcoming McClaren is using such a system, as are some race cars.
>>14801226
pport n/a making 600hp?
>>14801221
BMW's come I6TT
Several other performance cars come TT
I think you need to do some research
>>14801602
With four rotors yeah
>>14801625
I thought it was a 2 rotor?
I love em. But god do they sound bad at idle.
>>14801643
A 2 rotor can't make that kind of power na
>>14801644
they don't sound that different at idle unless heavily ported tb.h
>>14801646
so are we talking about a 2-rotor or a hypothetical 4-rotor production engine?
They are small and lite relative to the power output.
Those are the only upsides of Rotary engine.
>>14801648
You asked a question about 600hp na rotary and I answered? Not the anon you originally replied to btw
>>14801652
simplicity and robustness (when not abused) is also a strength
>>14801653
oh, ok
>>14801622
Sequential and not parallel?
Because you know I was talking about sequential.
Looks like that is sequential on the BMW. Well alright, but that's still a 7 year old engine.
>>14797681
Mazda just filed a new patent basically for the /o/ rotrary.
