hey guys i am looking to buy an FD and was wondering what are the pro's and con's of V8 rx7's i know many here would be against it. but i heard rotary engines are expensive to maintain.

 

Head over to the Other Engine Conversions forum and do some reading of the FAQ and some of the active topics. That will go a long way to answering your questions.

You can also perform a search under this New User forum for "LSX", "V8", or combinations as there has been plenty of discussion in the past.

 

just watch out, some people are sort of traumatized by the idea of putting an v8 into an rx7:P

 

The v8 is old technology that is used in almost any domestic fans swaps because they are cheap and plentiful for parts. I personally would never go V8 because I hate the sound. People in the past have brought up the argument that it would ruin the weight distribution of the car but the difference in weight is very eligible.(If I remember correctly it was less than 50 lbs difference) The Rotary can be reliable and not too bad on maintenance if it is built correctly, and tuned well. IT is a very unique sound and type of engine which adds to the coolness factor over taking the common domestic engineering approach of throwing a huge 5+ liter engine in a small car. Both have their advantages and disadvantages, you just have to look at your goals for the car and figure out what is most if benefits outweigh the downfalls of the swap.

Many "purist" will frown upon the v8 conversion as the car is a "rotary experiment 7" but at the end of the day its what makes you happy...

 

When you have the money to put into a Rotary and you want to be a purist there is nothing wrong with it. However the fact that they are no longer made, they are not at the power level to content with their older tech but far more reliable LSx counter parts so to speak esp on the tuning side with HP Tuners leaves a lot to see from the users stand point.

You can buy many variations of the LSx from a 5.3L to a 6.2L the smaller the cheaper (You can get 5.3L's in almost any junk yard for around 500.00 running) you can not find a used rotary in good shape for less than 1600 and they are few and far in between. Rebuilds seem to show issues with losing coatings inside requiring new housings that seem to be in short supply.
While the Rotary may be fun even Mazda is not supporting this motor they went to the next model and unfortunately its not doing that well either in my opinion. It's NA and uses the same amount of gas as its older tech V8 counter part with less than 200hp at the wheels which even the smallest of those LSx's makes stock. (My Vette was very cheap and easy to get over 400 at the wheel's NA with a baby cam and E85 on factory 243 heads) the market is huge in comparison.
By that lets illustrate it this way, when the new Camaro or 5.0 Mustang came out before it hit the show room floor there were aftermarket parts, people ready to tune it, etc. Most cars have to be released to then have parts developed for them. Old or not these cars have a following that far surpasses any other.

Is the Rotary fun, hell yes. Is it the right choice for future RX7 Owners... that's a harder question with the lack of parts and costs. If you have the money go for it, if you don't but love the car the V8 option is a great one.

Also the 20b as fun as it sounds, if the LSx is only 50lbs in difference how much heavier than an LSx do you think a 3 rotor 20b is? That's one I have always wondered just as a side thought.

Either way spend some time, there are great packages out there and it can go both ways but if you just keep losing money and that's not something you can afford to do then maybe you should consider other options.

 

Exactly, I plan on either a 3 rotor turbo or n/a 4 rotor for the final goal for the car, and it will weigh more than the lsx setup, although be capable of a lot of power. The main thing is that the sound is very exotic vs. the norm v8 rumble. when I said the weight difference was "eligible" in the earlier post it was supposed to be "negligible".

Another question that must be asked is "what are my power goals?" A 13b is not cheap to build to 500+whp reliably and their is a lot of parts that must be replaced. once done right though it is very rewarding. The issue of part availability is not really an issue for the 13b s if you know where to look, its not very difficult to find parts for.

 

I have a RX7 with bad coolant seals and I've been trying to decide between rebuilding the 13b or going with an lsx swap. The LSx swap is a lot of money but would be more reliable for and I think I'd keep the car longer.
I feel like if I rebuild the 13b its only a matter of time before it goes out again so the money put into it is kind of a waste.
I'd like to make it a daily driver only so I'll most likely do the V8 swap.

Let us know what you decide.

 

A ls1 swap will I give you reliable perforamce. Reason Chevy has put that motor on alot of there platform.
You can go to almost to any juck yard and get wht you need. But rotary are a very simlpe engine.

 

From what i can gather from talking to people and reading up, there are pros and cons to each side. not taking into account the "wow" factor or anything that makes it unique, here is what i can gather from both sides.
V8 pros: better gas mileage, more reliability, more available parts, gobs of low end torque, can have less parts to malfunction so less parts to replace, little difference in weight.
cons: buying or fabricating everything to fit, wiring everything in the car, fitting transmission and driveshaft, fabing headers and manifolds, basically any and everything that involves the swap can be a pain in the *** and expensive, can have little room to work on anything.

rotory pros: small motor makes it easy to work on and even take out of car, easily rebuildable, decent parts availability
cons: big fuel thirst, replacing parts more often, parts are expensive, very low torque (for NA)

if its something you feel like YOU want to do, dont let anyone tell you youre retarded for doing it. theres a reason so many people swap V8's into them for a reason.

 

Rotary...V8 is getting played out.

 

WOW, this looks actually pretty one sided (V8 guys giving pros and cons) and ill try to keep this brief and keep out my usual "V8s are horrible and rotarys are god" thing. Rotarys are not unreliable, let me start this off there, I know there are a lot of people out there who like to tell horror stories. but the fact is those horror stories come from bad experiences, and people who build these motors and have no idea how to. I dont feel like going over all the stupid mistakes one can make while building these motors, but there are a few for someone whos uneducated. So it all comes down to who builds your motor. Now second, they are not expensive to maintain, because im not sure of your goals ill just bring out this example, you could have a 1600 hp 20b for under $10,000, V8s actually take way more then that to reach those numbers. The purpose behind that? Theres not much to do, modifications are simple, but easy to mess up, so only have someone trusted do it. Your in LA, if you wanted you could Probably have Racing beat or Mazda trix build it. another reason they are cheep is because they can do it with stock internals. Rotarys are great motors, small, unique, and sound perfect. When you motor goes (will take a while, but everything gets tired, even V8s) then you can have it taken apart, replace the seals, and put it all back together and keep on going. Dont let horror stories make u turn a beautiful, unique car, into another V8 powered sports car. If you want that, i say just buy a Corvette..

 

Im sorry for the double post, but i just want to clear up somethings from this post. First of all, you cant say that the V8 has less parts to break because thats simply not true of any piston motor. A piston motor has so many complex, moving parts in it that it is always kind of fragile. And as i was saying in my other post, parts for the rotary really arnt that expensive, full metal seal kit is $1300, and you probably wont need all of that if your smart and realize when the motor is getting tired (youd have to be trying to ignore it to not see the signs, if you know them) if you do catch it, you might just need apex seals, which are $72 a piece (worse case youd need 6)

Rotarys and V8s are polar opposites, one makes Gobs of low end torque and the other one makes gobs of highend torque (dont let people tell you rotarys have no torque) it all depends on which you prefer. I, personally love the highend power, but if you dont then go for a V8.. but as i previously stated, i would prefer it if it was in the C5 corvette, that stole design from the Fd..

 

Hi,

I've owned both cars. A 330rwhp rotary and a 400rwhp LS1. Both cars are fast. The LS car is nice as a daily driver. Gobs of low end make it nice to cruise around town. Gets better gas mileage than the rotary. The rotary is unique though and is super nice to cruise on the highway cause it's quiet and smooth. If I do it all again, I would go with a 20B. Kind of a meet in the middle kind of thing. More low end, lots of potential high end and it is still a rotary. I always believed that Mazda should have put the 20b into the FD in the first place. I would recommend riding in/ driving both before you buy. Find some club members from both sites that are close to you. Most will be glad to show you their cars

 

i kinda wanna go v8 as well. but its soo expensive same thing with the rotory rebuilt kit..

 

Sorry, unreliable was the best word i could think of at the moment. What i was looking for was high maintanence for rotory. Unless youre a hardcore rotory fan, most people wont want to do the extra upkeep that is usually required for them. Plus, with the better power and MPG with a V8 despite them being 5.7L is also a key point for most people, and even auto-x/track day racers. Like i said before, take away the uniqueness and "wow" factor for either one, there is little pros for actually keeping a rotary aside from not having the money to do the swap. Im not hating on the rotary at all btw, i think its a great concept, but after chaning everything to get the max amount of MPG and still averaging only 20 MPG on the high way, theres little reason, for me personally, to keep it.

 

Ultimately, what are you trying to build?

 

Go rotary. A v8 does not belong in an Rx-7.

 

The main flaw I see here is the thought that if money is no object that you would go v8. I dumped 15k into my current build to go from stock to where I am now. I could have easily built a high hp v8 rx7 for that money but it just doesn't have any appeal to me as it kills the uniqueness of the cars rotary platform. I would say it is ultimately the other way around that if you want a cheaper rx7 to own it would have a v8 in it as building reliable power on the rotary is actually quite expensive. There is Cheap, Fast, and Reliable... Pick 2

The reputation of the rotary comes alot from misunderstanding of how the engine works, needs to be maintained, and lack of available mechanics that are trained on how to work on a rotary engine. If you overbuild the rotary for the amount of power that it is going to be making, and keep it cool, it is a great engine that is much better the the lsx IMHO.

 

+1

 

This subject has been beaten to death!

When it comes to a well-maintained rotary engine... Reliability is not an issue. If you're the type of person that likes to drive 1,000+ miles past an oil change, go ruin an LSx engine. Leave the rotary to someone that will treat it well.

It's your own personal preference... Making a thread like this, you're asking to be misinformed from both sides. I'm not saying that everyone is wrong. I'm saying that you'll just be more confused trying to keep track of pros and cons, and which pros and cons are even factual information.

 

hahah i know thats why i am loving this forum already!! except for the pts system thing though... well i am gonna use it as a daily driver and in the future i was thinking of doing mainly drifting.. why i decided on a rx7 is because its well rounded car... good for tracking and highways and drifting. i guess... i have considered a 20b but i just got here from singapore and i dont want to get a car thats gonna kill me on gas and maintenance... plus i am in school so something thats easy to find parts for etc etc would be ideal.. dont get me wrong... i have big respect for rotary engines... really i do... especially the 20b... but why i was thinking v8 is because firstly we dont get v8's from where i come from and always had love for jdm cars... so i was thinking why not make it the best of both worlds v8 rumble with good low end torque in a perfectly shaped body of a FD... yeah and i heard about the weight difference too... i heard its only 50lb difference.. but was wondering how much would 50lb's make...??

 

oh and also if i were to go with the v8 option does anyone here have a place/workshop near LA they can recommend to do the swap plus tranny?? and if i were to go with a rotary option any suggestions?

 

Look into the laws in swapping the engine in California first... They have the shittiest laws in the country when it comes to modifying cars and they enjoy giving tickets so it could be a deciding factor.

I know all emissions equipment have to be taken from the donor car, and that includes things like the fuel tank pressure and vapor solenoid and the whole obd1/2 system that has to function properly. Also, engine has to be the same or newer than the old one. not trying be be a buzzkill on the idea, just saying its better to be safe than sorry and doing the research is important.

 

i am a rotary purist so of course i would say stick to the 13b