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Engine swaps-what do you like?and where would you put it?


Considering LS-swaping a miata doesn’t majorly screw up the balance, I don’t think a rotary would be an issue.

Well, appart from the fact you now have a car with a rotary :stuck_out_tongue:


I love the way they sound, but personally, would never want to own one. As cool as the rotary engine is, I prefer reliability. Yes, I know, the stock rotary engine can be reliable, but any piston engine has a higher reliability just based on the method of operation.

Was more a hypothetical thought, that you take a normal, relatively-unassuming car known for good handling, and give it a mighty engine, but one known for being light and stupid powerful when tuned right, and see what comes out of it.

So essentially, you’d have a track day weapon that spends its non-track days sitting in the garage with the engine torn apart while swearing something evil about apex seals.


Ehh, from what I’ve heard, rotaries love to chug oil, run frickin hot and chew through seals all the time. That’s totally ignoring the fact that it gets next to no mileage out of fuel and is hard to drive with it’s lack of torque.


RX7 makes 261 NM which is hardly torqueless. Less than what most cars get, but not gutless.

Tuned rotaries do get bad mileage, but so will a tuned piston engine with a rich AFR. People like to think that just because LS engines get good mileage piston engines automatically get better mpg but the FD RX7 posts slightly better MPG values than a Lancer Evolution X. Granted it’s on 20 year old data, and owners report like 12-16 at most on city, but it’s still not much less. Older JDM spec Evos are said to get less than 10 mpg city.

Also rotaries are only unreliable in a daily driver sense, and yes 100K mile rebuilds are unacceptable no matter how you look at it. But in racing/tuned applications how many engines can realistically last 100K under high boost and heat? Rotaries don’t get “internal” mods aside from maybe seals, but even then most people use OEM seals until they start making north of 500 WHP. Prepping a piston engine for high power and boost can be costly, with all the balancing and porting and new internals needed.

The LS is special because it is that good (And even then they have their fair share of problems). Even engines like a 4G or 2J or RB will not be cheap to make power out of, despite what JDM bois will tell you.


I’d love to put GM’s 2.0L Turbo “LTG” engine in a Factory Five Racing 818C kit car.

Link for reference.


Rotaries consume oil largely because they are 2-cycle engines. While they are different from your Briggs and Stratton Lawnmower, Rotaries run on the same principle. That’s why a quart of oil is recommended to be added into the gas tank when refueling.


That’s a whole nother can of worms there. Some don’t believe in pre-mix some do. I know resident rotorguy @vmo doesn’t believe in it.


My younger brother is a rotary man (billet housing 13b turbo in series 5 rx7) and he swears never to use premix. His rx7 has done 60000km since the rebuild/re-engineered 18b bridge port and thats with a 66/68mm turbo and almost 2 bar boost. I am certain the mx5 to rotary has been done and its what i would do…but if i had a rx7 it would have a Aussie 351 cleveland with a single borg warner turbo…cause v8 for life


Many people have said that the rotary is not an engine that likes to be shortshifted. And anyway, our point isn’t to prove the rotary is a bad engine - there is no perfect one - it’s also not unreliable per se, more that it’s a high maintenance engine. It needs care. It needs love. Nothing wrong with that, we’re just pointing out the nature of the engine.


True. Because if you make the mod (the independent oil tank for the oil injection pump), and do you chech the oil levels between each fuel pumping, you don’t need this.

And caution to go to the MOT with premix.


Unreliable it isn’t.

For example, a 12A is very reliable (NA), the same for the 13B na and the 13B-MSP (Renesis). But in the 13B turbo engines, every 100k KM (with the stock turbo pressure) normally you need to open the engine and change apex seals (reccomended: ceramic apex seals. More expensive than stock ones, but more durable), and of course, all the seals. It costs 900€ this.

But with the NA rotarys, I’ve seen 350.000km RX8 without any issues and stock engine and not opened. You need to change the mind when you are driving a wankel. Is different to a piston engine.

Remind this: a wankel is like a baby. It needs a lot of cares and attention.


Exactly what I said. It’s not unreliable, it’s high maintenance.


All Briggs and Stratton engines we here in Europe have on our lawnmowers are sidevalve 4-stroke.


A lot of modern lawnmowers and small engines are going to four stroke, I was just citing an example.

As far as rotaries being unreliable, I seem to recall a teacher mentioning an aftermarket computer program for the RX7 that would bump the redline up to 9500 RPM. You could maintain that speed as long as you had fuel in the tank. Rotary engines also had the advantage of fairly high power outputs for relatively small displacement. The weak points were emissions and fuel efficiency.

Fun fact: The DeLorean and the AMC Pacer were both intended to use rotary engines. The Pacer was originally planned to use a rotary engine that General Motors was developing. When GM scrapped the project, AMC redesigned the front end of the Pacer to fit an inline six. Concerns over fuel economy prevented the DMC-12 from ever sporting a rotary engine. That being said, there would make some interesting engine swaps.


I’ve seen, on TV, a DMC-12 with a 20b rotary. Painted black, due to repaired bodywork.
That thing moved very nice when the owner put his foot down.:grinning:

The crap engine they put in it from the factory was a French-Swedish collaboration, the PRV6.
P - Peugeot
R - Renault
V - Volvo
6 - V-6

The only car maker that made something nice with it was Alpine, they put a pair of turbos on it.:smiling_imp:


Hell, if bot for the Back to the Future movies, you probably wouldn’t see any DeLoreans on the road today. They would’ve just faded into automotive obscurity.


This is an odd one but a needed one

Mk3.5 Volkswagen Cabrio with the 2.0L NA and 5 speed standard manual removed and replaced with the 1.9 TDI and 5/6 Speed manual for it

The only reason? The 2.0L is only ok and the 1.9 is a legend


An 86/BRZ with the V10 from an LFA would be mental, as would a 370Z with the twin-turbo V6 from the GT-R Nismo. This is yet another pair of examples of putting a very powerful engine in a relatively small car.


Both those cars with forced induction on their stock engines are pretty badass as well.


BRZ with any modern Porsche boxer 6. Add a twin turbo kit, and welcome to madness.