babylou

Well at least on this site you got the "pissston" thing right.

DRx

Did you just put a celica and a supra TT into the same post? LOL

1- = after all the TRD bolt-ons is still 111 hp/litre

2- = someone who has suped their supra to 700+ hp to achieve 300 hp+/litre would drive this car for 6 months to a year before major mechanical overhaul. If they are a daily driver in this car they are getting maybe 7-10 mpg and are destined to huge $$$ in upkeep. I've been to that forum plenty of times and have seen the results. We are talking STOCK production here, not a 335 hp car that has been retrofitted to simulate a jet engine.

3- = There is no concentration of stress in a rotary engine. Stress is based of inertia and friction. There is very little 'engine stress' as you put it because inertia is compensated by a centrifugal force, not a jabbing motion that you get in a conventional combustion engine. The only stress left at that point would be heat, and since the entire engine is made of alloy it would be dispersed semi-evenly and not concentrated anywhere.

IKnowNot'ing

Rotary engine have a poor THERMAL EFFICIENCY due to the very elongated shape of the combustion chamber (higher surface / volume ratio, longer combustion). A lot of the heat is lost into the rotor and the cooling system.

Compression ratio of Renesis is similar to piston engines.

The Power / Engine Capacity ratio is NOT a measure of efficiency.

The only measure of global efficiency of an engine is the ratio :
Mechanical Power Output / Caloric Energy Contained in Gasoline.

The Renesis is not the most efficient engine. Could be better if ...(see signature below).

For gas engine, global efficiency is about 35% (up to 46% for advanced traction diesel engines).

EDIT : what rotaries are good at :
- good power / weight and power / size ratios
- good volumetric efficiency (Renesis) thanks to effective intake tuning
- less moving parts
- good NVH due to quasi-rotary motion

Feras

iTrader: (1)

yeah my point is there is only 1 rotary engine period currently manufactured as part of a new car, and it happens to be the same exact engine in a race car. 1:1 certainly beats whatever the piston engine ratio is.

Purple Helmet

someone who has suped their supra to 700+ hp to achieve 300 hp+/litre would drive this car for 6 months to a year before major mechanical overhaul. If they are a daily driver in this car they are getting maybe 7-10 mpg and are destined to huge $$$ in upkeep. I've been to that forum plenty of times and have seen the results. We are talking STOCK production here, not a 335 hp car that has been retrofitted to simulate a jet engine.


that is such a joke! supras cost twice as much as rx8s so if it were a porsche supra or a ferrari supra then it would have instant credibility???? the only thing you have correct is the mileage, your ignorance overwhelms your intelligence when it comes to supras, as for celicas, What engine is LOTUS using in there cars right now?????? the Celica Engine!! humm now why is that????

Rotarian_SC

That is because some people in Lotus had ties with Toyota and could get the engine pretty cheap actually. Also it was NA stock engines with over 100hp/L.

Also what I wanted to point out is that not only are their fewer major moving parts in a rotary, but those parts are moving slower. At redline, the Renesis is spinning at 3000 rpms. That is not very fast compared to many non diesel engines.

DRx

Do you work for NADA or something? If you do, they should fire you. Youre now comparing prices on a car that went out of production nearly 10 years ago and has depreciated ~50% vs. something that is in it's first production year. Go check your history and find out how much a Supra TT went for new in 97, the last model year... I guarantee it wasnt $68,000. Loaded they rolled out the door just over $40k, which is only about $4k more than what a RX8 goes for with all options installed.

I just looked on Auto Trader and found a Supra TT rated 730+hp at the crank with 24,000 orig miles... selling for $24,000... more than $3k less than a base model Rx8 so I really don't see your point.

Supra's are great cars. I love them. I really think it would be cool if Toyota started building them again to compete with the Rx8, 350z and so on. The advantage they have is that they have been around for so long, companies have been able to make some kick *** mods for them.

The same thing will happen with the 8 in a couple of years... and I would easily anticipate a hopped-up Rx8 putting out 700+ hp the same way a Supra can today. People are already doing it with the 95 and earlier Rx7's. But they have been around for nearly 10 years as well. It doesn't happen overnight.

rxphink

Sorry if this has been covered but I didn't read the full thread.

The rotary engine is less thermally efficient than a piston engine because of the massive combustion chamber. The flame front has to travel a longer distance as compared to a piston engine and looses more energy because of the distance it has to travel.

Scotchee

That's exactly what I was thinking - I totally agree. The renesis is not very efficient.

But I love it anyway! I certainly didn't buy it because I thought it was efficient. I bought it (and now love it) because it is a blast to drive! The experience we have is not possible with other engines that weight more for the same power, don't rev as high as smoothly, and don't provide the same balance as our beloved engines provide.

Who cares if it's not AS efficient as other engines?!

Purple Helmet

I was referring to the original MSRP, the original sticker or bluebook, if you saw a TT for 24K either it was abused or there is a fool that needs cash asap or does not recognize what he has www.suprastore.com

BaronVonBigmeat

Wow, a ten year-old car which was priced at Corvette levels can be radically modified to make 700HP and, in theory, make the trip to work.

Best engineering analysis EVAR. Clearly, you are a professor at MIT. Oh wait, no...you're still in High School, spouting off about something you read in some magazines, to defend your wet dream car from Fast and the Furious.

Purple Helmet

Ok Ok BaronVonInsecuremale. you are right, You are ALWAYS right....

Purple Helmet

I had mine 4 years before that crappy movie came out FYI,

the last model year was 1998 in the US, it was in production in japan until 2000. So 1998 was 6 years ago, now any MORON can do basic math, and 10 years ago is 1994, and the supra was a 93.5 model year, yes I can see that you are a highly edumacated mathematician. You are now My official HEROE! Now go get that Mullet cut off, get a shirt with sleeves, and stop chewing tobacco!!and stop dating your sister errrrrr aunt errrrrrr mother errrrr

The engine is still in production today, you will find it in the US in the Lexus IS300, the GS300 and the SC300 the last two are not in production today. There is also a 1JZGTE that is in production overseas and that is a twin turbo 2.5l I-6 290HP little brother to the 2JZGTE.

Did you know Lexus/Toyota makes an AWD V-8 Sedan overseas.....that they have a host of turbodiesels corollas, landcruisers etc

An Inline 6, is a perfectly balanced engine as are V-12s and V-16s if cadillac actually makes that prototype a production and they are not, maybe a V-12, which bmw and mercedes makes and BMW still makes an inline 6 as its bread and butter, the Dodge Ram Diesel Cummins is an In-line 6, mercedes just rolled out a new turbodiesel that is an I-6, Suzuki makes a tranverse mounted I-6, strange but true

it sucks that we do not get to see what other countries see all the time, some pretty awesome vehicles, just keep Ford out of Mazdas engineering dept and its all good.

04 RX-8, infinity system, bose head unit.............

Purple Helmet

and when the supra came out it kicked *** on corvettes and could make 150mph faster than a Viper

Rotarian_SC

Wait, now I understand. So basically a V8 is much more reliable than a V4 because it has many more moving parts, because the engine stress is spread out over more parts. That makes perfect sense....not.

You could use the common sense of statistical probability, since you have more moving parts, it is more likely for one of them to fail.

Purple Helmet

what a bright guy you are, V-4, now lets see, thats right, SAAB used a ford V-4 in the Saab Sonnet, jesus christ is that a V-4 in my RX8 since Mazda is Fords bitch? yes folks its true, ford did make a V-4 , does that mean I need 4 spark plugs or eight?>

Purple Helmet

Uhhh we are so smart..... playing all those video games really helps our critical thinking skills

shelleys_man_06

Wankel rotary engines aren't as efficient as piston engines, if that's what you're saying. You hear 13B-REW engines are analagous to volcanos and white dwarfs; the rotary engine has a lower heat rejection rate than piston engines. Small displacement engines, such as the B16, 2ZZ-GE etc. have low heat rejection properties, too. This can either be a consequence of the overall surface area of the engine, its high-revving capabilities...er, I have to look this up. The rotary follows this pattern is a sense. Also, rotary engine's displacement is questionable. I've seen 1308 cc (Mazda's measurement), 2616 cc (according to Dave Coleman), and 3.9 liters. Regardless on how you look at it, power per displacement is not really a big issue. IMO, that issue is more about bragging rights. Sure 183 hp/liter is nice, but what does that mean in the real world. IMO, power-to-weight is more important than power per displacement. It is one of the premises for the RX-8's success, as well as its predecessors. Remember, even if you have a 700 hp/liter engine, it is no good if you stick it in a car whose weight greater exceeds that statistic.

wakeech

anyways...

to end this rediculously long and very silly thread full of misinformation, the term "efficient" can be construed and spun in so many ways in automotive jargon that you're gonna have to be a whole lot more specific about what you mean to slag the wankel.

as a segway that i want to get in here early, i assume that Dave Coleman is that guy at SCC right?? i don't care what that retard has to say, the displacement rating is correct: it is 1.3L in its own terms in the same way that you rate a 50cc two stroke motor as 50cc, not 100cc because it displaces that volume twice over the same period as a four stroke. you have to look at things in context, and yes for rating's sake in automotive contest, you'd have to equalize the displacement figure by about 2 and probably a little bit (and maybe more than that depending on porting rules) to make things fair. in the real world though, there are no rules, and the wankel is still a 1.3L engine.

and as another foot note before i even start talking about what this thread is about, horsepower per litre is nothing. it's talked about on every car forum everywhere, including this one since it was created so this discussion is never new. Brake Mean Effective Pressure is what engineers regard as truly the greatest measure of an engine's sophistication in regards to Volumetric Efficiency, and making the most power with what you have. and again, in the real world this doesn't apply, 'cause it's the most power you can get from the most engine you can stuff into whatever car it is you wanna make fast. variable cam profile technologies, and super duper whatevers are great and everything, but horsepower per litre is a ricer excuse for having a slow honda.

the wankel is not as thermally efficient, this has been covered already. no, this isn't why the 13B-MSP's fuel economy is so bad, it's the ECU tuning which has to do with keeping the catalyst alive long enough to qualify for the emissions standards.

that about covers it.