snub disphenoid

How is **** like this allowed to remain on the board? That was a completely useless post, 100% opinion, 0% fact. Please delete.

Then buy a stock FD, never drive it, never modify it, and put it in a glass case in a ******* museum. Some people buy cars to go FAST and LOOK GOOD. This car layed down 1200hp and can be detuned to 900hp for street driving with the T-56. He ran a 9.5@140+ when he slammed on the brakes BEFORE he went through the lights. That's fast no matter how you look at it, and you HAVE to respect it, unless you want to be an ignorant ****.

Please explain to me how a 5.7L engine that produces over 300rwhp stock and gets over 27 mpg is a piece of junk. The RX-7 was no supercar, its performance was equal to other SPORTS CARS of the same generation (300ZXTT, C4 Corvette, Supra TT), but it in no way shape or form resembles or performs like a mid-90s supercar. It's a sports car, which is really quite a different thing. I guess you're against swapping V8s into 240Zs, then, too? They were incredible sports cars when they came out, but V8's do nothing but enhance their performance, much like the LS1 does for the RX7. I guess you're also against putting SR20DETs into 240SXes, seeing as how that detrements the handling of the car by adding a turbocharger and related equipment to the front end. Pull your head out of your ***. The RX-7 is a ******* sports car, not a maclaren F1.

He didn't wreck the car, it was merely cosmetic damage and the car will be up and running soon. Maybe if you knew your *** from your elbow when it came to this topic you'd never have made such a retarded comment.

You see, people swap LS1s into FDs because they're changing the stock engine out for one that produces more power, lasts longer(in most all cases), has more parts available for it, is cheaper to maintain, and has a higher power potential. They're taking a powerful engine out of a heavy car and putting it into a lighter car. If you swapped a 13B into a Corvette, yes people would **** a brick, because it would be pointless, unless you wanted to be the first person to ever do it. You would be taking out the stock engine and you'd be putting one in that got worse gas mileage, didn't have a rear-mounted transaxle (so you'd effectively **** up the weight distribution), had fewer parts available that cost more to replace, typically doesn't last as long, and has a lower potential for making power. You see, there's actually a reason why people do this engine swap...who would have thought...

I'm not saying everyone should rip out the 13B in their RX-7 and stuff in an LS1, you do whatever you want to go fast or get your kicks. Hell, I still have a rotary engine in my car. What I'm trying to do here is I'm trying to point out some blatantly false opinions (yes, you actually have false opinions in this case) to discredit your argument. Maybe that way there won't be as many retarded arguments in the Other Engine Conversions forum.

jimlab

Which American cars would that be?

Who do you think builds Mazda's truck engines these days (not to mention the trucks themselves)?

turbojeff

iTrader: (30)

Small displacement motors in cars that are "joint manufactured" or just plain badge engineered from Japanese cars. Ford Courier (70's), Geo Metro, Escort GT (2nd gen), Probe, Eagle Talon, Dodge Stealth, Chevy Nova (late 80s-90s), Dodge Colt, etc.

Nothing notable really.

IIRC Mazda was the first Japanese manufacturer to sell an American vehicle with a Japanese brand, it was the "Navajo", AKA the Explorer.

kim307

iTrader: (1)

Also the new pontiac vibe w/ toyota vvtl-i I4, and saturn vue w/ honda vtec V6.

So much hatred. I don't know, but let's just say that I, myself, would never buy that UFO looking 1st gen rx-7 just because it's got a rotary engine. (no offense to 1st gen owners)

Cars are not just what its powered by, IMO. Especially a car like FD..... it's so much more than just its engine, it's got so much more to offer to its owners and drivers.

To each his own, why argue? Don't let me bust out with my reasons why Honda/Toyota is better than Mazda. I've done it once, real pointless and stupid, and will never do it again.

Just let it be fellas, let it be.

wingsfan

No...it didn't...and no it can't

The 1200 HP was an estimate that popped up on a video that surfaced from the Deals gap event. The car put down somewhere in the neighborhood of 700rwhp based on the practice runs. They dynoed on low boost in the high 500s IIRC.

Brian runs a powerglide. He hasn't run a t56 in a long time. This is now the second or third thread I've seen you post misinformation in. You're not helping the cause by getting your facts wrong.

It's fast for sure, but the fact remains that he ran 9.6ish in practice runs and mid 9.5 in his wreck run. Despite whatever potential the car may have, its no there yet. There are still quite a few bugs to be ironed out.



He hit that wall pretty damn hard. I'd say there's likely more than cosmetic damage. They haven't been real public with what broke.

wingsfan

It dynoed at 560rwhp @5100rpm @ 6psi & 19º of timing. He was supposedly going to run 24 psi and 26º of timing (which is a shitload/dangerous amount of timing for a boosted LS1, even if it was running race gas)

http://www.torquecentral.com/showpos...1&postcount=32

ironpanther

Coincidence or not that is something that the corporate people could have told their engineers to use as a design limitation. The 10A was designed as such because europe uses a doubleing factor for taxing rotaries. I am argueing though that race standards of measurement for displacement(2 rotations of the eccentric) are flawed because they don't take into acount the unique design of the rotary engine as much as rely on experience with four stroke piston engines. These standards are more likely to be created out of lobbying by the big companies that didn't want to restart their R&D programs because one company stuck it out to production and made a compact high performance engine.

I don't make arguements that aren't backed up. http://www.monito.com/wankel/mercedes.html The bold face term "Unfailingly Reliable" is taken directly from a mercedes internal memo regarding the C111s four rotar power plant. I tried to find the original article that directly cited the memo that I read originally but your going to have to put some trust in me here.

See above regarding racing standards of displacement measurement. ALSO the arguement that was going back and forth on this thread regarding if the 13b should be rated as 1.3 liter displacement or 5.2 liter. I was attempting to show the logic behind the 1.3 liter rating as compared to how piston engines are rated and why that method(2 rotations of the drive shaft) does not translate to a proper displacement test for the rotaries(as some v8 fans have so heartily argued).

jimlab

That's as fair as it gets.

OK, that made absolutely no sense whatsoever...

Then perhaps you should volunteer the basis for your argument in the future instead of having to be asked to provide it.

Wow, not only did you get that from a rotary propaganda site, you misinterpreted what you read.

"It ultimately fell victim to the oil crisis and a timid board with a "not-invented-here" attitude. This was a shame because the cars were unfailingly reliable and wonderful at holding the road."

Nowhere does it say that Mercedes killed the rotary project because it was reliable. Let me paraphrase for you... "ultimately it fell victim to the oil crisis". Stop there. Same reason that GM killed their rotary program.

Not likely.

I must have missed the 5.2 liter debate, but a 1.3 liter rotary being fed with 1 atmosphere of boost does indeed displace the equivalent of 5.2 liters.

Maybe you should concentrate instead on how the single eccentric shaft rotation method fails to represent the true displacement of the engine as evidenced by the amount of air and fuel ingested...

snub disphenoid

Alright, I'll just stop posting. I just thought I saw Brian mentioning that the car "met and exceeded the 1200hp goal" and also I THOUGHT I saw him saying he could/would change the transmission out for a T56 and then run lower boost for if he wanted to drive the car on the street. Seriously, I'm not being sarcastic, I may be wrong about what I saw/read.

mark57

The LS1 upsets arguments that nothing can be as powerful and light-weight as a 13BREW. "The FD3S was built around the rotary!", they whine; "Yes, it's okay to swap in the heavy 20B, but not the lighter LS1/6." The LS1 just upsets everything about the FD3S/FC3S including its ease of installation. It's too bad most of the detractors have never driven the conversion or have even seen it. They won't understand just how ignorant they are about this and about going fast until they do.

wingsfan

I'm sure the 1200hp rumor/estimate started somewhere, and Brian's the logical place to look. The way Brian described it was people were pestering him about the power output, so they doubled the known output of a single turbo car that they'd put together and threw that number out there.

Fact is his car didn't come anywhere close to that at the PGDs. Maybe he means on race gas once the kinks are ironed out, who knows?

They also changed the turbos from the t66s they started with to t76s (according to a post on TC by Lane), so maybe they're continuously monkeying with the setup until they settle on something they're comfortable with. There's so many rumors floating around about that car these days that it's pretty impossible to keep things straight. Getting a straight answer out of Brian has always been somewhat of a challenge as well.

As for the T56 aspect, it's certainly possible if a person wanted to drop the coin on it. I'd imagine it would require some setup specific hardware.

The T56 will certainly bolt to the engine no problem (duh, right?), but I'd guess it would require a t56 specific driveshaft, as the physical dimensions of the T56 and powerglide are different, and the driveshaft will likely need a different input yoke. I've never actually seen a powerglide, so I can't readily comment on it.

A T56 is also not going to stand up to the 900rwhp "detune" without significantly beefing up the internals. Bolt the garden variety T56 that comes with an LS1 to a 900rwhp motor and it won't last long. A 900rwhp would be useless on the street anyways. You'd want to detune it to 500-600rwhp, and even then you'll have serious traction issues below 100mph.

snub disphenoid

It seems that the car ran a 9.5@130mph because the car took the 90-degree right turn 300 feet before the lights. I don't know what that indicates, but I'd sure like to see what this car can do on both pump and race gas. Again, I'm sorry about posting misinformation, I'll either be 100% positive I have my **** straight or I won't post at all.

I suppose you could use a built T56, but they cost a little over $3000, but then you'd have to go through the trouble of changing out the driveshaft as well. I suppose it could be done, but it seems like they would be better off simply using another car for street duty.

And about the traction issues, is 500-600hp seriously the limit? I suppose there's just that little weight over the rear wheels...

ironpanther

Please enlighten me as to why it doesn't.

Two rotations of the drive shaft of a piston engine causes the engine to complete four cycles on all pistons which would cause the air measued to be equal to one combustion cycle on each reciprocating system(each piston) so one combustion cycle per rotar would be 6.5ccs per rotating system. Just because one rotation of the rotar is three combustions cycles is no reason that a standard of measurement should be applied as arbitrarily as two rotations of the eccentric when that is not even logical. Seriously if you were to create a standard of measurement of displacement on the rotary then you should either make it one rotation of each rotar(7.8 liters) or one combustion cycle in each rotating system(1.3 liters).

I'm done posting here though because jim you seem to like to argue for the sake of arguement and that gets nothing done.

kim307

iTrader: (1)

The reason is that rotary engines are not standard piston engines which was used to derive the standard process.

I really don't care what the displacement difference between rotary and piston engines are. You're just comparing apples to oranges.

Anyways, stop arguing and live on guys.

jimlab

Figure it out. If a "1.3 liter" engine is consuming more air and fuel than a larger engine at the same rpm, what does that tell you about the rated displacement of the engine? Or do you think it's more likely that a rotary engine produces about twice as much power per liter as a piston engine while having worse BSFC?

ironpanther

Jim your still avoiding the question. Kim is correct in saying transferring a standard of measurement form a piston engine to a rotary is like comparing apples to oranges. And to answer your questions. It tells me nothing about the rated displacement of the engine. What it tells me is that a longer flame path, heatsoak, and a a stock fuel map that is programmed extremely rich don't help in the fuel economy of the vehicle. So to answer your second question. Speaking as a mechanical engineering student that comes from a family of mechanics and engineers YES the fact that the rotary engine doesn't have cam shafts, push rods, a 90 degree power transfer, valves, rockers, or two bearings between the rotar and eccentric(which all tend to eat up kinetic energy produced by the combustion), plus makes this power on what some in the piston world would suggest is "low" compression makes the rotary engine a superior design when it comes to power transfer. I have done the figuring jim. The burden of proof is in your hands. I know I said I was done posting but your barkign piston rehtoric without backing it up and that is what Ic ame on here to stop on both sides of the table.

wingsfan

Wow, You sure showed him.

Our savior to the rescue.

jimlab

Sorry, but you haven't done anything but prove that you don't have the first clue what you're talking about... mechanical engineering student or not.

credible_hulk

jimlab, I don't really understand your problem with the calculation of rotary engine displacement. The standard for this calculation is: volume of one rotor face multiplied by the total number of rotor chambers. Every company that has made a rotary engine (NSU, Suzuki, Curtiss-Wright, Augustine, and of course Mazda) has calculated engine displacement in this fashion. I highly doubt they were all forced to due so by Japan's imposed tax on 2-liter and greater engines.

jimlab

Mazda set the standard, which the SAE adopted/endorsed. It's as simple as that. Of course other rotary engines are now rated the same way, and of course it has nothing to do with Japan's tax on engine displacement for those who don't sell in that market.

You're not listening, not understanding, or both. Displacement is pretty much irrelevant as far as BSFC is concerned. It's an indicator of how efficient an engine of any size is at turning fuel into power, and it doesn't matter if it's a 4-stroke piston engine or a rotary. If the rotary isn't efficient at turning fuel into power (and we know it isn't and why), how can it possibly produce a much higher output per liter than even a 4-stroke piston engine unless its displacement has been arbitrarily underrated? All of that fuel it consumes has to be mixing with something, so it's obvious that a rotary engine is taking in a lot more air than its rated displacement would indicate.

What the most accurate formula for comparison of displacement would be could probably only be determined by an engine dyno, which could directly measure the air consumption of a rotary and a piston engine of given sizes at the same rpm. Or, you could use the method that is used for NHRA and other racing classes with strict displacement limits (a P&G gauge test) to verify actual displacement without teardown. Regardless, doubling the rotary engine's displacement is "fair enough", and the policy that many governing bodies in racing have used for years to level the field.

The bottom line is, the only ones who stand to benefit from defending the underrated displacement of the rotary engine are Mazda (from a tax standpoint), and people who mistakenly want to use the high power per liter output of the rotary as some sort of proof of its superiority. What they don't understand is that power per liter figures are irrelevant, and that a "prehistoric" pushrod V8 producing only 96 hp/liter could blow the doors off a rotary engine producing 2 or more times that based on Mazda's displacement ratings. In fact, an NHRA Pro Stock big block only produces about 160 hp/liter, less than a stock Renesis at about 183 hp/liter. It doesn't take a rocket scientist (or a mechanical engineering student) to figure out which one is likely to win a straight line acceleration contest. So much for power per liter ratios.

It really doesn't matter one way or another what formula is used to calculate equivalent displacement, as long as you realize and understand that Mazda's and the SAE's method of rating the displacement of a rotary engine is absolutely not directly comparable to a 4-stroke piston engine, and that you therefore must make some sort of adjustment. Arguments like "well, if Mazda produced 5.7 liter rotary" when comparing to V8s are ridiculous. Mazda did produce a 5.7 liter rotary. It's called a 13B with about 18 lbs. of boost, give or take.

LT1RX7

OK here it is.
13B REW is equal to a 2.6 liter piston motor.

Evidence on a scientific base from a Rotary BUILDER:

Rotary Displacement

As rotary engine enthusiasts, we all know the obvious, intoxicating charms of Wankel wonder. Unique, unusual, lightweight, compact, high revving, what’s not to like? One of the most commonly deliberated subjects is “what is the rotary engine’s displacement”? An excellent question. Here’s our best to make the case for the engine’s displacement.

Conventional reciprocating engines are the standard that most relate to. We all know that these engines are measured by measuring the area of the bore, multiply by the stroke and then multiply by the number of cylinders. Simple as that.

For simplicity, we’ll use the 13B engine as the standard we’re calculating. You can use these ideas and apply them to a 12A or 20B yourself. The rotary engine is obviously unique. The engine has two rotors shaped roughly like a triangle. This makes for three combustion faces per rotor and a total of six for a standard two-rotor engine. Each face has a “swept volume” or displacement of 40ci(654cc) and there are a total of six faces. With this known, the engine displacement should be 40ci(654cc) times six to equal 240ci(3.9L), right? In a way, yes, but that would not be a comparable displacement to the 4-cycle engine.





Thermodynamic cycle breakdown of a Rotary engine.




Thermodynamic cycle breakdown of a piston engine.




The key for comparing the displacement between the 4-cycle engine and the rotary engine is in studying the degrees of rotation for a thermodynamic cycle to occur. For a 4-cycle engine to complete every thermodynamic cycle, the engine must rotate 720° or two complete revolutions of the crankshaft. The rotary engine is different. The engine rotor rotates at 1/3 the speed of the crankshaft. On two rotor engines, front and rear rotors are 180° offset from each other. Each rotation of the engine (360°) will bring two faces through the combustion cycle (the torque input to the eccentric shaft). This said, it takes 1080° or three complete revolutions of the crankshaft to complete the entire thermodynamic cycle. Obviously, we have a disparity. How can we get a relatable number to compare to a 4-stroke engine? The best way is to study 720° of rotation of the two-rotor engine. Every 360° of rotation, two faces of the engine complete a combustion cycle. 720° will have a total of four faces completing their cycle. 40ci(654cc) per face times four faces equals 160ci or 2.6L. That’s a well-reasoned number and now gives us something to be able to compare to other engines. In addition, since four faces passed by in the comparison, it’s like a four cylinder engine.

Now we know, the 13B compare well to a 2.6L 4-cylinder 4-cycle engine.

Or check out their website:
http://www.rx7.com/techarticles_displacement.html

LT1RX7

What happened no whitty I am a mechanical engineering student I did the math comments? So I have finally ended the whole displacement arguement with one post? Damn I am good.

travisorus rex

In your argument, reliability and practicality are non-existant.

Now using your standards, look at any top fuel car. Several thousand horspower (literally) from a :gasp: piston engine. V8 or not, the power to displacement ratio takes the 4rotor wankel and kicks it square in the nuts.

sevensix

iTrader: (1)

these threads....

v8 is a v8. rotary is a rotary. just take your pick and be happy.

because of personal preference i'll take rotary over v8.

maybe race classes should just be split up into weight classes. just limit a car's size and weight for each class

it gets too political with all the weird rules auto companys try to come up with to gain an advantage over competing companies.