ROTARY swap
03-01-2010, 03:26 AM
#81
it isn't light, and it isn't easy to put into the car. There is ABSOLUTELY no reason to put a 13B into a Miata unless you just want the fabrication exercise. Trying to argue that the 13B is in some way better than an LS1 swap or even turboing the BP motor that's already in the car is foolish.
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03-01-2010, 03:34 AM
#83
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You walked headlong into that one. A 1.3 rotary has a swept volume of 1308cc, but its effective volume is 2616cc because it combusts fuel every time a seal passes a port - there is no dedicated exhaust "stroke" per say. This is why ALMS classes Rotarys based on 2x their displacement. It's got a 4-stroke style cycle, but it makes power like a 2-stroke.
Also, each rotor in a 13B motor displaces 654cc (IIRC) - this would make a 3-rotor motor a 1962cc motor, which is a 2.0.
Want to know why we're bagging on rotarys? They suck. Rx7 guys with half a brain on them know this, which is why they dump them and drop LS1s into their cars too. The 13B doesn't do ANYTHING well - it doesn't make good low-end torque, it doesn't turbocharge reliably, it isn't reliable, it isn't light, and it isn't easy to put into the car. There is ABSOLUTELY no reason to put a 13B into a Miata unless you just want the fabrication exercise. Trying to argue that the 13B is in some way better than an LS1 swap or even turboing the BP motor that's already in the car is foolish.
Also, each rotor in a 13B motor displaces 654cc (IIRC) - this would make a 3-rotor motor a 1962cc motor, which is a 2.0.
Want to know why we're bagging on rotarys? They suck. Rx7 guys with half a brain on them know this, which is why they dump them and drop LS1s into their cars too. The 13B doesn't do ANYTHING well - it doesn't make good low-end torque, it doesn't turbocharge reliably, it isn't reliable, it isn't light, and it isn't easy to put into the car. There is ABSOLUTELY no reason to put a 13B into a Miata unless you just want the fabrication exercise. Trying to argue that the 13B is in some way better than an LS1 swap or even turboing the BP motor that's already in the car is foolish.
It's all about personal taste. I think the 1.6 and 1.8 in our cars suck ***** and aren't worth dropping the money some of you guys do, but it's your money to waste. I like rotary because it's different, almost forgotten other than the RX8. Not arguing against the fact that rotary isn't exactly good at most things, but it's still fun. Most fun I have ever had in a car was my 12A powered FB with bolt-ons (carb, header, exhaust and some suspension mods). I guess that is why I still hang on to two FB's that need a **** ton of work and don't run. Feel bad selling them.And to the OP again, there were plenty of 20B (2.0 like Sav said, indicated by the 20 in 20B) produced. Not nearly as many as the 13B's, but you can still find them floating around out there in several variations.
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03-01-2010, 03:37 AM
#84
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You ************* are making it seem like I am taking the OP's and rotary engines side! I'm so torn!
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03-01-2010, 04:04 AM
#85
They can turbocharge reliably, they have a rep for not being such due to the hugely complicated TT setup on the FD's that frequently broke down, and poorly modified FC's that did the same. There is a sizable contingent of original engine'd FB's running around in excess of 150,000 and 200,000 miles, and FC's are not unknown to behave as such once the achille's heel of the thermal pellet is fixed.
The don't turbo charge any more unreliably than any other engine, given an intelligent owner and proper tuning. True they do not take well to detonation, but a well sorted engine ought not do this anyhow. Just go talk to a REAL racing team that field a rotary and try to tell them their engine if fragile...
They'll laugh at you. All of the serious SCCA guys I know rate their engines in SEASONS till failure while their competition rates theirs by RACES. If preignition is avoided, they are an extremely robust engine, especially under the rigors of competition.
Furthermore, well built examples, while not known for their stump pulling torque curve, are known to lay down a torque plot as flat as kansas, making for a very pleasing driver.
And finally, they're just so damn easy to work on, and actually pretty cheap, barring ceramic apex seals. Stay with steelies and used parts, and you can go a long way for your money.
They are not however: magic or any better than a v8, and a swap using one is just as you said, a fabrication exercise. Strictly comparing the 1.6's and 1.8's in miatas, they are FAR easier to get to 400whp, but I think a 400whp miata is a waste of time, and stock ANYTHING is more reliable than a modded 1.8 or a 13b, so V8's win there too.
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03-01-2010, 09:56 AM
#88
There comes a time when more power is detrimental to its useful application. Thing is, few complain about said excess. I have a 200whp miata and it feel damn near perfect, or rather, all the abilities of the car are about equal. With 400 it'd be a point and click fest.
But really all I'm saying is a rotary swap is kinda fruitless because a 1.8 will make all the power you can feasibly use.
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03-01-2010, 10:15 AM
#89
It's threads like this one that make me not want to do my planned 13B-RE swap... However, I have a different purpose and have fabrication skills. BTW OP, hope your 'tech teacher' can fabricate you a new front cover, or your swap is already dead unless you know which one to buy...
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03-01-2010, 10:35 AM
#91
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Go find a mazda dealership, make buddies with the service manager, service writer, or a few techs... Then ask them about the glorious RX8.
They'll tell you the truth about the car. Listen to the sales pitch to potential buyers from good experienced sales reps.
Ever stop and ask yourself, why did the rotary completely disappear for a number of years? I think there is a valid reason the engines are "almost forgotten" most of which were pointed out very truthfully by Savington.
They'll tell you the truth about the car. Listen to the sales pitch to potential buyers from good experienced sales reps.
Ever stop and ask yourself, why did the rotary completely disappear for a number of years? I think there is a valid reason the engines are "almost forgotten" most of which were pointed out very truthfully by Savington.
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03-01-2010, 10:36 AM
#92
Having no internet at home FTF!!! I cant believe I missed this one. I have to say when I got my first car I thought dropping a rotary was the most ballerz ideaz eva!!!! ... I learned though is practically pointless 
but is all about taste and self satisfaction and like Joe said once..... I cant wait for someone to post about wanting to put 32 chainsaw engines into a miata
but is all about taste and self satisfaction and like Joe said once..... I cant wait for someone to post about wanting to put 32 chainsaw engines into a miata
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03-01-2010, 10:38 AM
#93
But I do agree with some of the earlier statements... This swap is not something to do if you can't afford a few extra hundred to buy ONE engine. What was so special about that engine that isn't the same as every other 13B out on the market? Ported? Built? Also, there is a key on your keyboard right above the Crtl key and right next to the Z key. It's not just there for show... They even put two of them on opposite sides to double your chances of using it. 
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03-01-2010, 10:39 AM
#94
I highly doubt you are going to pull it off, but I AM basing this judgement on your use of simple grammar, like capitalization and punctuation, so I may be wrong.
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03-01-2010, 11:02 AM
#96
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Now, I personally think you are a troll, someone messing with everyone here, but in case you are not: Do you realize how far from succeeding this project you are? Anyone that says: “I have a motor, is there anything I need to know” is very fare from actually going out in the shop and performing the swap. About as far as a 15year old boy with bad acne watching a porno on his room is from screwing a cheerleader. If you haven’t even bothered to find the right forum (miata.net has a complete section for motor-swaps and you kind WILL be welcomed there), you don't bother typing something resembling to english and obviously haven’t spent 20min on google, why would anyone take you seriously?
Just turbo that little 1.6L bitch. It will be a blast. God luck.
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03-01-2010, 11:07 AM
#97
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The reliability think truly is bullshit
Stock, they will run very reliably for a long time.
The main problem comes when people modify them. They are extremely sensative to small changes in everything you do to them, and require immaculate tuning.
If you take a bone stock FC RX7 and put a straight pipe exhausts on it, without tuning, its likely to blow up
How many times do you think some misinformed ricer has made that mistake?
Then you take into account all the other modification people do, raising the rev limiter way too high, etc.
then, on top of this, when you beat on them they burn oil faster than normal, so yet again, how many ******* riceres do you think have run the engine out of oil by beating on it all the time and not paying attention to the oil level?
Its very obvious how the huge numbers of ricer-destroyed wankels could lead to this misconception.
Now, all that being said.
Their obviously is a lot of merit is swapping to the LS engines. It does end up being about the same weight as a fully dressed 13B and significantly lighter than the 20B.
The engine will never make low end torque. Is that because its a wankle? No. Its because it was designed by mazda to be a sports car engine.
There have been many other wankel engines that are designed to make low end, mazda didnt build their engines like that because its ******* stupid.
We, of all people should know that torque output at 2k rpm is ******* useless.
Stock, they will run very reliably for a long time.
The main problem comes when people modify them. They are extremely sensative to small changes in everything you do to them, and require immaculate tuning.
If you take a bone stock FC RX7 and put a straight pipe exhausts on it, without tuning, its likely to blow up
How many times do you think some misinformed ricer has made that mistake?
Then you take into account all the other modification people do, raising the rev limiter way too high, etc.
then, on top of this, when you beat on them they burn oil faster than normal, so yet again, how many ******* riceres do you think have run the engine out of oil by beating on it all the time and not paying attention to the oil level?
Its very obvious how the huge numbers of ricer-destroyed wankels could lead to this misconception.
Now, all that being said.
Their obviously is a lot of merit is swapping to the LS engines. It does end up being about the same weight as a fully dressed 13B and significantly lighter than the 20B.
The engine will never make low end torque. Is that because its a wankle? No. Its because it was designed by mazda to be a sports car engine.
There have been many other wankel engines that are designed to make low end, mazda didnt build their engines like that because its ******* stupid.
We, of all people should know that torque output at 2k rpm is ******* useless.
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