NissanConvert

iTrader: (1)

The R10 is crazy. I don't think that diesel will take over because it's so difficult to make workable in a high-po application.

j9fd3s

iTrader: (3)

no, he's right a USED lsxx engine is cheap.

if you're rebuilding the lsxx engine and the rotary, the rotary is still less money.

Roen

iTrader: (2)

Don't forget, the true displacement of the 13B is 3.9L, IMHO.

The FI multiplier depends on CFM and temperature anyway, it's hard to say what number to use.

I know I'm a minority in that point but here's why.

http://mikesdriveway.com/misc/rotor.doc

The reason why many people think it's more towards a 2.6L is due to the 2 strokes per rev argument. That argument assumes the induction is at a 1:1 ratio. Since the rotary runs at a 3:2 ratio, that must be multiplied on top of the 2.6L. I had a whole explanation in another thread on my argument of functional equivalence.

In fact, the rotary should be performing closer to the 4.0L 6 cyl engines, but it's still underperforming in that respect. Then again, it is an old engine. The 16X engine seems to be better in that regard, but it needs to make as much power as a 4.8L 6 cyl before it's satisfactory in my eyes.

It's more important to check the power numbers than the torque numbers, since you can multiply wheel torque by changing the differential gear ratio higher by 1.5 times.

The rotary engine must be more taxed anyway, as it must run at an rpm 1.5x's it's piston counterparts to make the same amount of power.

NissanConvert

iTrader: (1)

I disagree with your maths, but I'm not going to threadjack. The rotaries main problem is a lack of torque because of the method that the burn energy is transfered to the eccentric shaft. It also loses some efficiency because it has a "rectangular" combustion chamber. It's advantage is in it's strong, hot, exhaust pulses.

Torque at the flywheel is important because torque dividing or multiplying gears further reduce efficiency.

Roen

iTrader: (2)

the maths are laid out in the word doc, and they are quite sound. Love how everyone objects, but no one actually looks at the evidence.

the main reason for their lack of torque is the fact that their torque is multiplied by 2/3 due to the internal gearing. You multiply the dyno result by 1.5, you get numbers that reflect piston engines for that power level.

NissanConvert

iTrader: (1)

I looked at the word doc. Moving blocks around doesn't make the math sound. I already said that i wouldn't discuss it further, and i won't.

Internal gearing? hp is always torque vs. rpm.

none of this has anything to do with the OP.

Roen

iTrader: (2)

No, but I'm sure power strokes make the math sound. Scroll down to which piston engine's power stroke most resembles a rotary engine. You'll see an exact match, but it's not the one that everyone thinks it is.

Internal gearing has everything to do with it. Piston engines don't have rotor gears around a stat gear which change the number of strokes per rev, they have fixed 1:1 linkages. The gearing impacts induction, which is why the usual 2 strokes per rev argument doesn't hold water, since that assumes that both engines in comparison are 1:1.

but you're right, this is a threadjack.

The Driver

iTrader: (4)

I'm talking about basic wise not Clk-Dtm's lmao.

Funny part is mine doesn't smell like gas an oil, very nice an clean for the most part but then again I have the stock MP with the air-pump hooked up.

All I think of when I hear a V8 is... mullet.

I will agree that a high pitched 8 like a 360's or a gallardo's 10 might be a different story. However if you want to talk 100k amazing sounding cars just look at the scoot 4 rotor 12A and tell me thats not exotic and simply beautiful sounding.

djseven

iTrader: (56)

showoff

the funny part about that, is it seems v8-rx7 owner's actually use the car more for what it was built for!! which is road racing!!, iam not even being sarcastic, just thought of it and i chuckled cuz the rotary die hards pic the v8 rx7 owners as knuckle dragging piston owners that only care about goin straight and dare they say (ruin the 50/50 weight balance lol)..when the opposite is more true, most v8 rx7 owner i know build the car 4 the road course and occasonally drag them..but with that said i believe the fastest i.r.s fd is still a rotary, but i do know of some v8 rx7s that are BLAZING fast around a road course

stylEmon

iTrader: (2)

Thanks, it seems to me that rotor-heads are extremely over-zeleous when it comes to slapping a turbo on a car. Probably because no one wants a NA 7, (I wouldn't)

ALL piston guys I know drive/build the car with out boost, then once the car is ready, they add their FI. It's the last thing on the list (other than paint). Even if they have low comp pistons, and they know a turbo/blower is in the works, it's still not added until the car is making max power and putting down good numbers NA. That is very rare in the rotary circle.

djseven

iTrader: (56)

I have seen several v8 fds at drag strips, but never any at a road coarse. We had a couple v8 swapped fcs at our road coarse event we hosted last year but no FDs. I just will never understand the v8 in an fd argument as long as the z06 is dominating the fd and can be had for the same price if not less than lsfd Just seems logical to have the better interior/better handling/ all around nicer car that originally came with the LSX than do a swap.

Ive heard guys so it is the challenge of doing the swap themself or the rarity. If that is the case, make a rotary powered fd run correctly. That is enough challenge and rarity in itself

I honestly could care less if people swap them, however I think the guys who do it will look back in about 5 years and say "i should have just bought a used z06"

zenofspeed

iTrader: (1)

Post #95 FTW.

There has to be some N/A displacement that equates to the power level of a 1.3L FI 13b. It doesn't matter what the exact N/A displacement is, but it is somewhere upwards of 5.0L.. x2 for 2-stroke and another x2 for 1bar of FI is as good as any other estimate. It's not perfect science, but what is?

The point is the V8 with the same max power has more area under the curve, is more reliable due to dropping FI, gets better mileage, etc. You don't have to lose weight distribution, suspension geometry, or A/C, or anything!

All I can ever find in arguments against the V8 is Rotary sentiment and loyalty..

I challenge anyone to PLEASE list what good things you LOSE when you go V8..

In your opinion (looks aside), does or does not the FD have some superior characteristics over the Z06? I always thought an FD could/should have better handling, weight, etc.

Roen

iTrader: (2)

without suspension work, you wouldn't really gain weight when going to an LS1, but the distribution would be off slightly. With coilovers, you can adjust it with corner weighting, but that's another story.

Physically speaking, the car would be slightly less responsive due to the mass being increased at the poles. Even this is only slightly noticeable.

Other than that, not much.

Now if you go with aluminum side housings on the FD and a VMIC to save piping weight, then there would be a significant weight savings staying with the rotary.

djseven

iTrader: (56)

The fd is an amazing machine, however a stock twin fd with basic track upgrades, exhaust, r compounds(300-330rwhp typically for an fd) will not run with a stock z06 on rcompounds. You can pretty much just throw some road race tires on a zo6 and have a race car out the box. The FD is no joke by any means, however the z06 is a whole different animal. And I am just talking C5 here.

To answer your question, yes it does have superior characteristics that is why own fds and not corvettes. However, my common sense tells me if I want a LS1 powered all around great sports car that hte corvette is the correct decision.

The Driver

iTrader: (4)

Took the words out of my mouth

1QWIK7

iTrader: (33)

Exactly.

For the same price, you can have a C6 z06 instead of buying an LSx swapped FD. Because at least with the vette, everything else is relatively newer and you actually have an american car. Must be weird when people ask what kind of car you have? And you say, "mazda rx7". "o nice what you have running in there, i dont know about rx7s". And you say, "o it got a v8". That person must be like, O... uhhh cool?

Something about the v8 grumble coming from a japanese car doesnt sound right. It almost seems "redneck" like. As much as the FD looks simply stunning, IMHO its supposed to have a import sound, not a "yeeehaww partner" type of grumble.

I like v8s and i love imports, mixing the 2 doesnt work IMO.

Like mixing oil and water, sure you CAN do it, but for what?

ptrhahn

iTrader: (9)

Effectively speaking, YES it is—

"Mazda" nameplate or not, these are/were cars engineered like exotic cars. It's a racecar for the street, like a Ferrari. Everything from the paper-thin body panels, to the race-type clutch, semi-solid bushings, everything reduced to the minimum for weight savings, etc. It's essentially a Japanese Lotus—with all of the positives and negatives implied in that.

The cardinal mistake being made when they came out, and now, is that people think they're buying a friggin' 626. It's simply NOT a car to drive to Sonic for a GD hotdog. Or to beat araound a college campus, or commute to work in. They're meant to be parked in a garage, taken out on weekends or to the track, and pampered.

If Lotus had produced the EXACT same car, flaws and all, they could've charged twoce the price, and nobody would be bitching. The reason you don't see so many other high performance cars like Vipers, Porsches, Lotuses, etc., in disrepair is because they're largely weekend cars owned by people who can afford the mainenance and that's required and are smart enough to get it done.

If you treat these cars like what they ARE, they aren't NEARLY as unreliable as they've been made out to be. I can see the appeal of a V8 conversion, but I just can't understand after all these years where all the surprise and bitterness about the car comes from. The car is what it is.

mdpalmer

iTrader: (24)

Regarding the "power under the curve" issue: If someone can give some dyno data files (torque VS time, as in two columns of numbers in a text file) for a 350 hp rotary turbo FD and a 350 hp LS1 powered car I'll be more than happy to do the calculation. I will do it on my own dyno data, but I'm not even at 300 whp

Will be interesting to see the results, since I hear people throwing that around all of the time. Remember, power under the curve needs some qualification, if you add it all up from idle to redline (or even from 4k-8k as in an all out drag race), you may end up surprised what the rotary engine has to offer If you add it up from idle to 4k RPM (stoplight to stoplight drag racing), sure the V8 wins, etc. etc.

Oh: and regarding the fuel economy issue--it's appears that most rotaries have larger BSFC figures as compared to piston motors of comparable power... and hence the increased fuel consumption in most rotary powered cars. I will have to back that up with some numbers though

silver93

I've made several posts about why I went LS1, so I'll try not to be repetitive. But regarding some of the items brought up here -

Doing 80mph on the highway, in 6th, I get around 32-33mpg. confirmed by the OBDII scanner I have plugged in for engine stats and by just general fill 'er up math.

All the math aside, and the theory aside, no doubt you can build a 13B faster and with more HP than an LS1 and visa versa. After owning an FD since 2000 or 2001, can't recall, I'm at the point where I just don't care about being the fastest or have the most horsepower or the most goodies or whatever. All I care about is having a good amount of HP, and being fast (as opposed to fastest) and most importantly - not having to work on the car every weekend or worry about it overheating, overboosting, not starting, flooding, or whatever.

The bottom line, the reality of it, is that for me, over the past 2 years of LS1 ownership, daily driver, etc.. I've never worked on the car except changing the oil. Its started every time, never overhated, and when my girlfriend drove it for 2 weeks, I never worried about her overboosting and blowing a seal, about it not starting because of flooding, didn't have to go through a long series of instructions and things to watch, etc... Like my Mac I got last year "it just works".

I'm sure everyone's rotary works great, they maintain it, etc.. but the reality is that 9 out of 10 people know exactly what I'm talking about and 9 out of 10 posting on the 3rd gen section deal with the same problems over and over.

I'm not bashing the rotary, just pointing out the obvious which everyone knows and is aware of. But for me, I don't care about soul, and the love and all that BS. Its a car with a weak engine. I, and most LS1 converts, no longer had the time or energy for the constant monitoring and hand holding of the rotary.

My 2 cents, fwiw

habu2

That is a valid point, but only for a single event. Built to the same standards and driven the same way, based on past experience on this board the rotary willl need to be re-built 2-3 times before the LSx would. That makes the rotary option more expensive over the life of the car.

Roen

iTrader: (2)

Power under the curve from idle to redline of equal peak hp LS1 and 13B turbos, the LS1 should win every time. The 13B turbos need boost, the LS1 does not.

As for the previous Z06 comment, you can by a C6 Z06 for the same price as an LSX FD????????? Since when? Shoot, I might just build an LS7 FD and trade it for a C6 Z06, and then resell the Z06! Pretty good way to earn money if that was the case.

habu2

I want to make power over as much of the usable RPM range as possible. The lower the better, and the higher the better. I can spin the rear tires at 2000 rpm, and I can spin them at 6700 rpm, what "idiot" wouldn't want to be able to do that?

Same here.

My LSx starter motor makes more torque than your Honda engine. If you seriously think you can compare your Honda to any LSx, well....

Spoken like a true ricer.

Again, spoken like a true ricer.

djseven

iTrader: (56)

I think he meant c5 z06. If you could get a c6 z06 for the same price as an lsx fd the swap would be even more pointless.

cozmo kraemer

I said it was a stretch when I was making the comparison, just much less of a stretch than not scaling for the fact that one engine is FI and the other isn't. I was using it as a starting point to generate conversation on the topic. If you are going to talk HP/L between a 2 stroke, Forced Induction rotary, and an aluminum pushrod V8 (which is apples to oranges) you have to try and get them into similar terms somehow. I was just conveying that point (they needed to be scaled differently) not that my numbers were exactly correct or accurate.