Which is more reliable? a ls1 swapped fd or a stock fd with a new rotary motor.

 

Obviously depends how clean the swap is.....and quality of the "new motor"....

But in general the ls1 is clearly the more reliable power plant.

 

reliable is a very roundabout word

ANY engine is reliable depending on how you care for it, rotarys can last over 200K, some can't

boinkers are the same way

 

I agree with lduley, every engine rotary or not will be unreliable if you don't keep up with proper maintenance and car for it! But personally i'd prefer a rotary over and Ls1 any day! That's just personal preference!

 

what is your metric for reliability?

also, your question is sort of loaded as asked because i am tempted to say the LS1 Rx-7 may be more reliable than the stock Rx-7 even though i believe a 13B is just as reliable as an LS1 viewed in comparative contexts.

 

You're not comparing apples to apples. The rotary is like a 4 or 6 cylinder non forged turbo engine, rather than the non turbo v8 that the LS1 is.

In the majority of cases a naturally aspirated gas motor will be more reliable than a forced induction one. Also an engine that has lower hp to cubic inches ratio will be more reliable than one with higher hp to liter ratio as you're putting less strain on the motor.

Clearly the larger liter LS1 non turbo is more reliable than the smaller turbo rotary...

Not to mention piston engines and the LS engines have billions of tested miles, engineering and R&D where the rotary doesn't have 1% of that.
I wouldn't want a V8 engine FD, I had one and sold it within months. Plenty of mustang or corvette if that's what you're looking for, or there's always swapping a 5.0 into a miata so you don't take out a rare car in the FD in the process.

 

Piston engines seem to be more reliable....however, that is a generalization. I will say though that I have seen 750k mile stock block piston engines, cant say I have seen that in a rotary no matter how well cared for. But lets be realistic here...rotaries also get a lot more abuse..you have to rev them much higher to get comparable torque. And sports cars like the rx7 tend to be driven harder that your mom's toyota camry.

 

In my opinion any engine can be reliable as long as you take care of it. But even for racecars pistons would probably last a little longer than rotaries

 

As others are saying, piston engines are definitely more reliable in a sense that they will probably last longer and you wont have to rebuild them as soon/as much, but that is not to say rotaries are not reliable as long as you preform proper maintenance your rotary should last you a long time.

 

i don't think they last longer because they are piston engines, i think it has more to do with two main things: (1) they have been around in constant evolution for longer than rotaries have been in consistent evolution, and (2) they lead much less violent lives.

for my first point, i'm deliberately limiting my statement to the Wankel-type rotary. while many manufacturers have dabbled with rotaries over the last few decades, it's pretty much been a Mazda show for quite some time.

for my second point, if you look at 2-stroke piston engines versus 4-stroke piston engines, it may make more sense. from the standpoint of how long they last between rebuilds, i don't think 2-stroke engines go as long either.