Big bad scary Rotary turbo.
 

Well, it's official; you guys have forever terrified me of the Rotary turbo. I know about 4 people who have had just delightful experiences with the FC's N/A engines, however after reading piles of information about how problematic and how expensive and hard it is to maintain the FD I'm simply depressed. :(

Many people share this problem and remedy it with a V8 LS1 swap. I can't help but frown on the whole ordeal because it transforms the car into something else, a more "primitive" type muscle car relaying on displacement to make power, and I'm sure the weight distribution is changed up (unless your eliminating everything up front A/C et al.).

Solution that I've been thinking of is the SR20DET. The engine would have no problem making 255hp; it has a great aftermarket and support following in the states and is really not that expensive. Personally, I feel the SR20DET would do a good job of trying to maintain Mazda's original intent of using a lighter-weight, small displacement turbo engine to provide great gains of horse power with superior handling in style.

While buying a shell and doing the swap sounds great, I really DON'T want to convert the car to a piston engine. I was thinking of buying a 10-12k FD, doing the preventivitve maintence (~700) and running it as long as possible. If it dies, maybe by then I fell in love with the Rotary, if not it would seem to be wiser to do a SR swap from a finacial and pratical stand point.

The SR will provide nearly the same amount of power. It will have cheaper parts and I will have more luck getting help from a mechanic on it (I live in the midwest). The SR will certianly get better gasmileage (people where saying they get 25mg
:eek: ).

Any, I already know there will be a big crowd of "rotary forever" guys and all shouting, however I'm hoping despite this one or two individuals could point me in the direction of where to find more information on this or give some helpful advice. I ran a search and didn’t come up with much. Bottom line for me, what is worse a FD rotting with a blown rotary, a FD with a V8, a FD with an I4 Turbo, or a wrecked FD that was bought by some idiotic kid with his parent’s money?

:whipit:

Stuff like this scares me.

just to let you know... from those that have done it or are doing it.. its a bigger pain in the ass to install an SR in a FD than a 20B... I will see if I can get one of them to post on here but I hear its a hell of alot of fab work and custom pieces..

20b is the three rotor rotary right? Isn't that JDM engine for the FD though?

Nope. The 20B is from the JC Cosmo sedan, which was only sold in Japan.

This thing?
http://img.photobucket.com/albums/v2...c/s3400090.jpg

Also, how would a 20b fix any of the problems. One guy over on vortex has had his conversion in the shop for like 3 months, and I've read else where it would cost around 10k, not to mention I would imagine parts being even more scarce. :confused:

Primitive? Weight distribution destroyed? Sure it is. :rlaugh: Poke around abit you might be surprised what you find.

My mechanic charges $35K for arebuilt 20B with instal into an FD witch is about 5K cheaper than anybody else that I have seen.

Great it wieghts 55lbs more... its still "primitive"

Why not buy three FDs then?

Don't come in here poking around about an ls1, it'll kick your ass. And what do you mean by primitive? The rotary has been around almost as long as the 350. Is it not primative? What are you getting at?


-Destin

yeah i dont get it either... the rotary motor is not any less primitive than a V8. in fact I am only taking a guess here, dont take this the wrong way, but I have a feeling my 1998 LS1 motor is a little more modern than the rotary motor that was in my 1987 FC... again, just a thought.

could it be the ability of the LS1 stock computer to be full reprogrammable in a windows format?
or is it the all aluminum V8 with a plastic intake that is not-so-old-school?
or how about the unbeatable power-per-dollar when retaining reliability with only a penalty of 100 pounds?
or is it the inexpensive upgrades available since the LS1 has sold in such a massive quantity?
or the excellent fuel efficiency while producing huge power?

:wtf1:

Well anyways ,good luck with your project and finding a local mechanic who will work on your highly superior engine that is only sold in japan. Back to my cave now.......

The whole v8 = "primitive" thing is hackeneyed and probably a result of ricers getting off on how "advanced" they are to be antaganistic to the 'enemy', which is v8s. I'll agree, 80s v8s were pretty damn junky. But to call a LS1 "primitive" or unadvanced is ridiculous and uneducated.

Oh well, considering most ricers probalby desnt even know wtf a VE% is, or why pushrods actually have several advantages over DOHC designs, and probably thinks that big displacment is a bad thing :rlaugh: and also doesnt know that SR20DET is smaller than a 13B because rotaries are volumetrically twice the mazda displacement, its not too unexpected.

Displacement is the foundation any engine is built on. VTEC and all that related bunk is just trying to make it use the displacement it has better. Revving really high is just using the displacement you have more times per second. A turbo is forcing more air/fuel in your displacement than you get from cylinder vacuum and your induction setup. But, in the end, it comes down to displacement. BTW, displacement isnt related to the external size of the engine! And PUSHROD engines tend to have more displacement for their size than DOHC designs. Imagine that!

BTW, when youre running forced induction, even small displacement increases are VERY profound. Makes it easier to drive, and the turbo spools up a looot easier.

Oh, and the forum had a zillion posts about how the v8 swap doesnt change handling and hardly changes the weight at all. One guy with a LT1 is 60 lbs heavier on the ass end than the front! And a LS1 FD pulled 1.13Gs on a skidpad :D

Jesus H. Christ...

A. How am I a ricer? I have never owned an Japanese Import, and I have never (read this,) NEVER made a cosmetic conversion, adaptation or enhancment to any of my cars. :nono:

That said, regardless I'm not a V-engine fan. I don't like V6s, V8s, VR6s or even W8 (Double V 8). Sorry, it's simply my prefernce. I am fully aware of power potential of such engines. I simply prefer inline engines, to ME, they are simplier.

Maybe "primitive" is not the word... "basic" then? The 13b is far from simple or striaght forwards, damn right complicated, similiar to a 1.8t. Rather then making a staright forward 2.4l engine (ala Mivec) to produce ~160hp, VW makes some godawful 20valve engine and slams on a turbo. Its complicated, its over engineered its a headacrhe.

Second, I didn't know this form existed, mods moved my post, the link to this isnt on the main page.. :rolleyes:


Lastly.. great the LS1 is the single greatest invention of all times, it owns all engines imported, exported, domestic and alien. Its so great it wasnt even crafted by man it was found in Roswell where it powerd a hyperdrive alien saucer producing 1900hp and allowing it to travel through time.

I simply wasn't exactly intrested in having such advanced alien technology in my car and was looking for some information in using primative, crappy ass garbage Nissan junk, seeing how everyone is tossing their's in the garbage and I could maybe get a deal on one. :bowdown:

Dude. I have a 20b fc and I give the ls1 props. It's a sweet motor. Maybe not the best but it has alot of good characteristics. Anyways if you do a search you'll find a couple of articles about sr's already swapped into rx7's. One fd and one fc. Welcome to the forum newb.

-Destin

What is Primitive????
 

I was in attendance at the Frankfurt Automobile Show in 1967 when NSU introduced the RO-80 sedan, the first production Wankel rotary engined car. I spent some time driving RO-80s in the late 60s-early 70s. I have followed the development with great interest, and have owned a lot of rotary powered cars, including a number of RX-7s. I am sure others on this forum know more than I about tuning and modifying the rotary engines, though I have done my share. But I think I am imbued with the history as well as anyone here.

The Otto cycle piston engine had been around for years before Carl Benz and Gottlieb Daimler built their cars in 1886. Dr. Wankel's rotary compressor was not turned into an engine until the 1960s, as I recall. But NSU, Mercedes, GM, and numerous others have invested years in research on the rotary. Mazda has been the one company that stuck with it and has made the greatest advances. Their racing victories, especially at Lemans, leave no doubt about their technical accomplishments.

About 10-12 years ago, Mazda was bragging about their very advanced Rotary test engine, which managed under absolutey perfect laboratory conditions to get a thermal efficiency within 10% of current piston engines. In the real world, with a well tuned fuel injected Mazda rotary, you can expect to get thermal efficiency about 15-20% worse than a modern piston engine.

Now that Honda and others have developed engines that can optimize the fuel delivery, ignition, valve timing and even the number of valves opening, the rotary no longer has any advantage in size or weight per horsepower. Even the smoothness is less of an issue with most modern piston engines.

It is true the 6 port motors are able to vary and optimize some of the same equivalent conditions, but the limitations are very restrictive. The very nature of the rotary engine cycle and combustion process will almost certainly never allow efficiency to equal the piston engine. If 45 years of intensive development is not enough to catch up, maybe it is time to move on to something less primitive.

Yeah LS1 seems to be the way to go, mainly because it is a proven route. However where are you guys getting the figure 20-24mpg for fuel economy? Consumer Guide got 16mpg on premium for both the Corvette and the GTO. ?

Corbic,

I know guys with LS1's that can average 28 mpg. Go to their sites and check it out. You have to remember that if consumer did get that figure, it may have been an "average" that included spirited driving as well. The funny thing about that is that it is still better than what I am getting out of my rotary right now and that is without spirited driving.

Joe

The FD is 700lbs lighter then a Camaro, I'm sure that'll get you another mpg or two :)

Personally if my FD starts giving me major grief I'll be looking at swapping an S2000 motor in to her, light weight, 9,000rpm and Honda reliability :)

They get 17-18mpg on their RX-7

I got 30+ mpg on a trip to Dallas and back, but not on the stock tune. I started with a full tank, put 402 miles on it, and then topped it off again (using ~12.6 gallons IIRC).

The LS1 factory tune is pretty rich (AFR in the low to mid 11s), and I'd leaned it out for cruising conditions to an AFR of low 13. Basically stuff it into 6th, and run at 1800 rpm the whole way (75-80mph).

jimlab, jimlab, jimlab...

lets see if that works;)

You need to spend more time in an FD to realize why FD owners generally are very pleased with their car. Most real sports cars are cost money to maintain. I don't car if you put a civic on the track, it will get to costing alot more than you antipate. If you are thinking of swaping, you are asking for trouble. If you want an ls1, by a c5, they are a great chassis, and you can my one for less than a modded fd. if you want a jap car with an sr20, get the car that the motor was designed for, a 240 sx. Those are respectable cars, their downfall stock was the lack of horepower. If you like the look of the FD, park a roller in you garage and just look at it. Motor swapping is a night mare. Even beautifully done cars that seemed well engineered end up disasters (like the one that lost oil pressure, lock up the rear end, and hit the wall while doing the quarter mile). Anyway, just my 2 cents.