Piston Engine vs Rotary. Your Opinions.. Experiences ETC

[Fryman]

{Possibly the ultimate mechanical debacle}

Hello all!

Ok, the debate that has been going on for years amongst the irc mechanics and metrosexuals.. Which engine do you believe holds greater potential.. in terms of reliablity displacement and any other detail.

Im opening up a can of beans here, people feel strongly for both sides.

Keep it a clean fight, gloves on! Put up your point of view and give it some substance.

Poll included...

[Rossco]

Street - Piston
Strip - Rotary
Track - hmmmmm? Very close.

My 2 bob

[DanWA]

Street - Piston
Strip - Rotor
Track - not going to comment haha
Reliability - Definately Piston

[[RX2]]

ohh fu<k, had both... been there done that.... die hard fan...
street= atmo rotor or piston motor ... rotor as w/end car!
strip = ROTOR
track = dont know never dealt with it

allthough i would like to point out that is with my own personal driving habits
some people can drive a turbo rotor as a daily & not have a drama, me i cant help my self .... i cane the living **** out of a rotor.. not just a bit ... i beat the living piss out of them,
therefore i end up braking it,
a piston motor is just not the same, & to thrash it its completely different,
thats why when i have a piston motor i take it easy,
but even then you give me a piston eng to thrash on the street & it wont last half the flogging that the rotor copped.

[Rossco]

kinda off topic but...

Best for f*cking neighbours within 1klm off at 3:30am - 12A Periphial Port

[1JZNOSHIT]

I see [D1 RX7] has voted :)

[Joe]

Ultimate strip - Rotary.

They launch so ****in hard, and go hard.

Ultimate street - Piston.

Not so loud, bit more reliable, more torque in many cases.

Ultimate track - piston, or late model IRS rotary powered vehicle.

Early rotaries arent "too" bad on the track, but IRS equipped cars **** on them...piston engines can be setup to create more torque, which is desirable on some tracks.

Not to sound too controversial, but I'll take a Series 8 RX7 over an R34 GTR any day of the week ;)

[Boza]

rotors street/strip & maybe track too...

as of late i know of a few sr's, 26's etc that haven't had exceptionally long lives so the story of rotors ****ting them self quicker than piston motors & not being reliable etc is a thing of the past in my opinion... :)

go the rotors... :werd:

[[RX2]]

rotors street/strip & maybe track too...

as of late i know of a few sr's, 26's etc that haven't had exceptionally long lives so the story of rotors ****ting them self quicker than piston motors & not being reliable etc is a thing of the past in my opinion... :)

go the rotors... :werd:

haha yeah beau, look at your m8 dave , he just bought rigs's old s2 rx7 ... 12a turbo ... i was telling him how that eng was in my old sedan...still going strong in 2005... never touched... was an import motor in 1992!! ...crazy!

[HotAe92]

street: Piston
Strip: Rotary
Track: Corolla :)

[Fryman]

slow down there egghead. i dont believe there has been a rotor versus piston discussion here before. if so then count my ignorance and apologies.

what is displayed here is simply a matter of opinion and a topic of discussion. it wasnt a case of what is better or worse, more a proclaimation of peoples preferences and experiences.

If you dont wish to participate, then that is your choice, otherwise you may let others say. The internet is full of stupid, this topic doesnt come close.

[RB20ZED]

at the end of the day the piston engine is here to stay it uses less fuel is better for the enviroment can make a fair amount of hp but it is a little harsh and isnt as smooth as a rotor is. rotors make a decent wack of hp and are very smooth at doing so but there reliability stakes aint so good. i think the rotor is a good idea for a engine but with not alot of development to make it as good and reliable as a piston engine . piston engines will remain the majority for ever on

[180 sx]

lol the question will all have ask our selves here...mmm why are mazda the only company to make rotories. If they were so good, wouldnt every company do it???? ask your self that!!!

[[RX2]]

lol the question will all have ask our selves here...mmm why are mazda the only company to make rotories. If they were so good, wouldnt every company do it???? ask your self that!!!
haha there was a few that gave it a shot, but then they chucked the towel in ,
& cliffs comment is true, but they are tryn to develop a cleaner rotor eng , hence the Rx8 donk is half way there

[Rossco]

']but they are tryn to develop a cleaner rotor eng , hence the Rx8 donk is half way there :werd: Renesis is a beautiful engine and will pave the path for the next generation of mazda rotaries.

[13Beast]

']haha yeah beau, look at your m8 dave , he just bought rigs's old s2 rx7 ... 12a turbo ... i was telling him how that eng was in my old sedan...still going strong in 2005... never touched... was an import motor in 1992!! ...crazy!

They last if you treat them well (like a girlfriend - they need maintenance! - then they'll love you forever - well you can hope anyways haha)

Oh, and they last a helluva lot longer if you get them tuned by someone OTHER than Rotomotion or Formaz ;)

[Morgs]

Having had both of them at some stage or another, and having to make a choice between keeping a 700hp+ RX7 and a R32 GTR - I've have to say rotors represent the best bang for your buck.

Side by side the RX7 and the GTR - the rotor is so much less complex and its much easier to learn how the thing functions. The simplicity of the thing also means that rebuilds are alot cheaper; I'd much have rather rebuilt the 13BT than the RB26.

Rotors do have that halo above them that so many people claim they need regular rebuilds. The design of the motor means they generally don't have the strength when it comes to surviving detonation like the average piston motor - however - looking at highly modified rotor versus highly modified piston motor, you will need regular rebuilds no matter what you're using.... as long as its well tuned and maintained you will generally be OK.

My personal choice was to keep the R32 GTR, and I'm still happy to have gone with the piston motor, despite the costs I do prefer the piston motor.

[Mike_Hunt]

Both have their advantages ( eg. lot more piston motors around with aftermarket support) but I like the rotor.. around 3-4k for a fully prepped race motor vs some of the insane amounts of cash some people tip into piston long motors to make em survive - because of their design there's no need to replace the guts with forged steel this, chrome moly that. The small physical size means you can sit em right back in circuit cars for better weight distribution (even though you don't have to with something like series 6-8 rx7's - near on 50/50 balance and mint suspension from the factory - beautiful). As for the reliability thing - it's like any motor, the more power you make the more careful you have to be with tuning and the shorter the lifespan. Although personally I like not having to worry about dropping a valve, throwing a rod, cracking a head...

[munchmunch]

Oh, and they last a helluva lot longer if you get them tuned by someone OTHER than Rotomotion or Formaz ;)


what the hell is wrong with rotomotions tuning im sick of every one ragging on them and not giving a reason so can you please tell me what is wrong with there tuning and who YOU recomend

[1JZNOSHIT]

Didnt Holden put a rotary in a Kingswood?!

[pshrdeta]

mazda put a rotary in a kingswood-called the roadpacer i think

also did a rotary bus which was very slow due to lack of torque

[the mekanik]

My first car was a 13B extend port carby RX7 and ironically it was the most reliable car I've ever owned. It was stolen, run dry of oil (leak), run dry of coolant and it survived just over a year of hardcore p plater thrashing and all it went through were tyres :)

Only downside was it went through a fair bit of fuel

I don't know anything about the turbo rotors though, if they're less reliableor whatever. Detonating must be pretty harsh on a rotor though

[the mekanik]

also did a rotary bus which was very slow due to lack of torque

It also had 4 wheel drum brakes, imagine putting down a mountain in Japan with 30 people in it, scary :eek2:

[tmz_99]

mazda put a rotary in a kingswood-called the roadpacer i think

Right you are! :) Specs:
MAZDA ROADPACER AP
YEARS: ... 1975 - 1977
MADE BY: ... Holden / Mazda
ABOUT: ... Length: 4850mm
Width: 1885mm
Height: 1465mm
Wheelbase: 2830mm
Track (F & R): 1530mm
Weight: 1575kg
Engine: 13B Rotary
Displacement: 654cc x 2
Compression ratio: 9.4
Power: 135ps/6000rpm
Torque: 19kg-m/4000rpm
Seating Capacity : 5
Top Speed: 165km/h
Turning Circle: 5.7m
Transmission: 3-speed automatic
Price: 3,835,000 YEN (ex works)
Total Produced: 800

there was a prototype rotary torana as well..
http://www.holdenhistory.com/TGLprotpic.html

[fculater]

Oh, and they last a helluva lot longer if you get them tuned by someone OTHER than Rotomotion or Formaz ;)




what the hell is wrong with rotomotions tuning im sick of every one ragging on them and not giving a reason so can you please tell me what is wrong with there tuning and who YOU recomend



yeah no **** put up or shutup

[TJ]

If would go piston engine every time, only because I have 0 experience with rotors.

tj

[Shano]

Rotos are expensive but they know their sh*t..

I think both types of engine give you a completely different driving experience.
I love driving a rotor because another rotorhead will *always* give you a wave and that knowing look that shares your pain! Something that in my experience doesn't occur between pistons (a, there's a lot of 'em, b, there's probably slightly less headaches..)

[13Beast]

yeah no **** put up or shutup

I put over $12000 through their doors in something like a 6 month period... and still got treated like ****. And im not one of these people who expect good service coz im a paying customer - I believe good service should come no matter how much or how little you spend. John Clements is a top bloke, but he's terribly over-worked, and I have serious concerns with the ownership and management of the place. A guy i used to know went down there to pick up his series IV after it hd a turbo motor conversion, exhaust etc - had a bill for $5500 he was paying in the office and he asked for a rotomotion sticker - Graeme then told him they were five bucks each and he had to pay for one!
I was going through some of my invoices after having my motors done there, and i was getting charged some ridiculous figures like $80 for example, for a s/h piece of vacuum line! (probably gleaned off one of their wrecks out the back - or just a strip of 5/16 fuel line :P
And when i had a motor put in with microtech, hi-flow, FMIC etc etc, the thing ran like a total pig. Probably tuned for WOT, with virtually no street tuning. I began to hate the car coz it was virtually undriveable on the street - and i know of rotors with crazier mods than my old car, which ran aftermarket ECU's which ran a 1000 times nicer (admittedly never quite as tractable as factory - but still a vast improvement over mine).
Also, and this im sure everyone will agree - they take WAY too long... Fair enough they are busy - but if you're going to take 6 months with my car, then how about ****ing telling me? Rather than telling me to ring back every friday and checking to see how its going? Anyone who works in a business knows thats NOT the way to run a shop and deal with customers. I also had dramas like them voiding warranties on a second motor i had installed by them (coz the first blew within 24 hours - again, BAD tuning)... Thing is, they can get away with treating ppl like ****, coz there isnt much of an alternative to turn to.
'Cept John Otter who builds some NICE motors (as Clayton and Jordan will attest to) and also Kim Ledger (the original guy who set up and used to run Rotos) has gone partnerships with another ex-rotary racer from Wanneroo and have set up a workshop - they supply and tune most of the cars at the Rotary Shop in Willeton. I forgot the name of the workshop, but when i find out i'll add it to the thread. If i ever own another rotary - i'll be taking it to Kim. They operate under the radar, not many ppl know about them (first i'd heard of them was a couple weeks ago) but i've checked out a bad-ass 20B Cosmo they set up - fully rebuilt, FMIC, nicely tuned Microtech and running 5psi on this massive Garrett put down 360hp at the rears. Trouble was, the auto g/box kept changing gears at about 5000rpm - and they still got 360rwhp... The motor combo can take 12psi from that turbo... Do the math - with a full manual valvebody mod to the auto, and 12psi - BIG hp at the rears - prolly 500 + easy. Obviously they know what they're doing!

[13Beast]

Anyways, I dont really want to get embroiled in a flame war about whether Rotos are good or not. Its my opinion, which may differ from other peoples out there. I had a number of bad experiences with them and I chose to do my business elsewhere - and with good reason to do so, IMHO

[Sketch]

Gimmie 1 cam, 16 pushrods, 2 heads and Three hundred and seventy eight cubic inches of displacement and im a happy man.


untill i blow it up

[Fryman]

nice work!

[munchmunch]

13 beast under stood bro but i have a 100k old 13bt motor got a decent turbo on it i made 290hp on 7psi at the rears and its running a real safe tune cant be to bad i have had to wait a bit longer than usual aswell but there work speaks for itself in my case

[180 sx]

I have nuthing really against rotories. Buying one for my project car..which will be some time ay....Anywayz they dont seem to be that cheap ay. Looking at prices :( mates said the **** was cheap. I gave em some prices for upgrades and they went running

[13Beast]

Yeah, in my experience its not hard to make power from a 13B Turbo... I dont think Rotos are the only guys who can make it happen. They'd have you believe that tho. Graeme told me years back when i was there picking my car up, that Rotos did all the machining for Maztech, Ric Shaw and all them! According to him they send all their motors over to Rotos to get machined etc... As if no-one in the east coast can do it as well as Rotos... What a joke!

[Boza]

is true david...terry stacey has done alot of porting/machining work for eastern staters...also rotos have built a few tough n/a ported rotor engines for eastern staters in the past...(unsure bout nowadays tho & or 13bt's etc)

[Joe]

Kim Ledger (the original guy who set up and used to run Rotos) has gone partnerships with another ex-rotary racer from Wanneroo and have set up a workshop - they supply and tune most of the cars at the Rotary Shop in Willeton. I forgot the name of the workshop, but when i find out i'll add it to the thread. If i ever own another rotary - i'll be taking it to Kim. They operate under the radar, not many ppl know about them (first i'd heard of them was a couple weeks ago)


LF Performance.

[Mike_Hunt]

I think Ledger's new workshop is called LF Performance - heard of some reasonable work turned out from there. I've dealt with roto's quite a bit and while they do genuinely want to help you out they really have crappy time/job management skills. Unfortunately since Formaz got rid of the parts side of the business (roto's took most of the stock I think) there's less options for all the fiddly **** you need..

[13Beast]

If anyones bored, go check out the black Cosmo they have in the Rotary Shop's showroom which they built.
Its enough to drool over....

[Shano]

Cosmo has been sold..
LF's produce some very, very nice work - if you're willing to pay for it. They modified and maintain the V8's they use at the AHG track, in addition to the Rotary Shop RX-7's and their purpose-built racecar!

[Jazza]

Never driven a rotary, all i know is they love to rev n sound **** hot well the s6-8 rx7s and even the new rx8s wit a nice zorst do. Heard about reliability problems with them but no personal expierance. What i wana know is why do they make lots of power but you never see lots of boost screwed into them? Even with management n bigger turbos i never see heaps of boost into them??? Does the deigsn of the rotar just not deal with too much boost well or somethin?

[Joe]

A rotary engine makes 3 power "strokes" per revolution per rotor, where as a car makes 1 power stroke for every 4 revolutions per piston.

Thats why they pump so much air to spool big turbos, use a relatively large amount of fuel, and make a ****load of power for not a lot of capacity or boost :)

[Fryman]

Contemplate this for a point..

The piston engine has had over 100 years of development and research. Felix wankoff invented it, but couldnt get it right due to thermal issues. NSK took it and used it in the 60's in various automotive experiments. The japs (more specifically, mazda) took the engine and developed carbon apex seals and other auxilaries to basically proof of concept the engine. ONE company has been on the forefront of development for this engine, and thats purely Mazda.

All in all, people would have give credit on the fact that if one company can make some success out of what was basically a concept with flaws, imagine if the "oil crisis" Rotaries were the forefront of technology, then every automotive bigwig ran for the hills due to oil scares. Imagine, if the 60's and 70s oil charade didnt strike, how much more advanced the chooker would be.

Constant development and refinement is taken on the piston motor, and still the rotary proves to be a competitor with everything basically the same as the original design, bar seals and porting.

My 2c.

[[RX2]]

well said dude

[180 sx]

A rotary engine makes 3 power "strokes" per revolution per rotor, where as a car makes 1 power stroke for every 4 revolutions per piston.

Thats why they pump so much air to spool big turbos, use a relatively large amount of fuel, and make a ****load of power for not a lot of capacity or boost :)
isnt that why they made a 4 piston motor :) :boink: :shake: nuthing against rotories, I just could affort it with my 500km week driving. Dumping one in gemmi soon!!!

[Joe]

Yeah but then there is 4 power strokes for every 16 ;)

a 2 rotor has 6 power strokes for every 2 rotations of the rotors!!! :D

[13Beast]

3 combustion chambers at all times in each rotor housing, so a twin rotor has 6 combustion chambers (hence the 6 cylinder ruling in some race classes)...

And the reason why they make so much heat? - A high surface-to-volume ratio (in terms of whats exposed to the heat of combustion...)

Here's a question for the past and present rotary owners - Has ANYONE gone for a synthetic?? It was a bit of a hot debate on this rotary owners mailing list I was on age ago - (given that they run carbon seals out of the factory and many synthetics have additives that actively "eat" away carbon deposits etc in motors...)

There was one guy on this list (from the USA) who had a series 5 turbo, still with all the factory internal carbon seals, and he was running a synthetic - and had been for the last 60-70,000 kms with no adverse effects! Yet, the common theory (and what I've always believed) is to stay well away from synths and run a multi-grade...

Experiences/thoughts guys?

[SimonR32]

BP 98 : $1.30 a litre

GAME OVER ROTOR !!!

[Joe]

Oh the huge rotary synthetic debate..

Seeing as rotaries do burn a bit of oil IE via the oil injection, I dont know if synthetic is going to burn as well as a mineral based oil. Best off just going with a tried and trued mineral based oil.

[[RX2]]

DUDE ROTARY'S HAVENT HAD CARBON SEALS SINCE THE 1970'S
all 12a & 13b produced after s1 rx7 12a have had factory steel seals
no wonder why a s4/5 13bt had no affects

[[RX2]]

BP 98 : $1.30 a litre

GAME OVER ROTOR !!!
fu<k 98 go c16 @ $8.20 a litre ! oh yeah :squint:

[Jazza]

thanks for tha explination Joe/others, rotarys in principle sound very smart.

[NAVO]

I must say i love the rotory concept, and a rotary is definatly on the cards for the future, simply cause they love s@#t high revs, and they just go so hard, its unbelievable.

But the longitivity and durability of a piston engine, and simply because replacement parts are so easily accessable, will always leave me hooked on a piston. I love to see some substance to an engine, having a tiny little beast tucked away in a small corner of the engine bay, isn't very scary to me, although, makes for better chopping when it absolutly hammers on the road. and i think that the power that a rotary makes speaks for itself.

but for now, i'm for the mighty pistons.
cheers
ash

[180 sx]

how things are going nowadayz, Im not sure if piston or rotary engines are going to be the future, as fuel prices are way way too pricey and there are many more substances on this universe that will combust better then fuel, so there will be new and better engines to be seen very soon. I might keep my engine (piston) for as long as I can before i get another rebuild, bc I can see that there is gonna be new and better things to come very soon!!

Getting my mum to get a new rx8 :P cant wait to give that beast a run for its money. Anyone know how that car goes stock and does it drink the fuel more then the v8 5.7lt genIII

[SimonR32]

rotary engines are proving very well adapted to hydrogen combustion, bmw are also spending a lot of money developing hydrogen combustion as well. dont rule out a internal combustion engine cause of fuel prices because they will still be around just using a different type of fuel. i dont think that we will be running out of hydrogen anything soon...

stock rx8 are not that fast, might just run a high 14... there fuel usage would be just a little better than a gen3, those suckers drink hard

[180 sx]

yer thats y i asked. Bc that gem3 loves the fuel. Hydrogen has some good advantages and will be able to produce more power then petro when alot more study has been done!!

[lysdexia]

my sister has a 25 year old series 1 RX-7. mechanically it's standard. being carb'd it's a pig until it warms up, but once it has, i would say it's one of the smoothest cars i've ever driven. also, i get excited seeing the tacho up around the 8k mark, my RB30 has rev cut at 6200..

[vy ss ute m6]

yer thats y i asked. Bc that gem3 loves the fuel. Hydrogen has some good advantages and will be able to produce more power then petro when alot more study has been done!!

they drink hard, but, if you get em tuned properly, they use less fuel, more power and with a proper exhaust, use less fuel for more power than the old 5L holdens.

[Dim]

i am pretty sure the renesis or whatever its called has pretty good fuel economy, good enough to win all those awards and stuff.

[got boost]

ive had em all n/a and turbo rotas.all the early rota's except a rx2
lotsa fun and good bang for your buck.
ill stick with my rb26 now though


pic is my r100 with 12a pp. ran 13.5 at ravo. and didnt my neighbours love it :werd:

[Fryman]

im sure they did.. making a ****load of noise and smoke on warmup.
Living next to a retirement home dont help.

The debate is still alive, suprisingly. All input is appreaciated and if ppl wanna understand, best be it this way