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1999 Miata Engine For An RX-7

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Old 03-31-08, 10:42 AM
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MX3
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1999 Miata Engine For An RX-7

I'm strongly considering putting a Mazda 1999 Miata Engine in a 1993 automatic RX-7.

What is your thought on this?

My main reason for doing so is because of fuel economy.

I know that I will not get the same performance as The Original Rotary Engine but I should get better fuel economy and mileage.

Do you think I should do this or not?
Old 03-31-08, 10:44 AM
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No. Just keep it in a miata, you will get better MPG anyway.
Old 03-31-08, 10:47 AM
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I think you should jump off a cliff. Completley erase that thought from your mind.
Old 03-31-08, 10:49 AM
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Will work for horsepower

 
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Buy a honda!
Old 03-31-08, 10:49 AM
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Originally Posted by FlyinFINN
I think you should jump off a cliff. Completley erase that thought from your mind.
Can you tell me why? Why are you advising me against it?
Old 03-31-08, 10:50 AM
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Originally Posted by 93rx74lyfe
No. Just keep it in a miata, you will get better MPG anyway.
Can you tell me why? Why are you advising me against it?
Old 03-31-08, 11:04 AM
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That's a great way to put a bunch of money/time/effort into your car just to make it worth less than it is worth now.

Why not just get a Miata as a DD and keep the FD pure?
Old 03-31-08, 11:15 AM
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There is no engine in it at the moment. It is a roller.
Old 03-31-08, 11:20 AM
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Do IT!

i think it'll be sweet and it will **** off a lot of rotor boyzzz.

you can always supercharge or turbo it later.

Be different!!
Old 03-31-08, 11:23 AM
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Originally Posted by Brismo7
Do IT!

i think it'll be sweet and it will **** off a lot of rotor boyzzz.

you can always supercharge or turbo it later.

Be different!!
Thank You. Atleast someone agrees with me. Do you know of anyone else who has put a Miata engine in an FD3s?
Old 03-31-08, 11:29 AM
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Originally Posted by MX3
Thank You. Atleast someone agrees with me. Do you know of anyone else who has put a Miata engine in an FD3s?
nope, cuz it's a pointless swap.
Old 03-31-08, 11:35 AM
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You are all against this yet none of you is really backing it up with a reason.
Old 03-31-08, 11:41 AM
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You really want to go from 245 hp to like 120hp ? Miata's dont even get good enough gas mileage in the first place. Put that same engine in a slightly heavier car and your gas mileage may just not be there anymore. Sure the Miata's have a good engine and its got great power in a 2200lb car but its not something to put into an FD. If you want better gas mileage and for some reason dont want a Miata buy a Nissan 240sx.

PS: I just realized it was asking about a 1999 not a 1990 like i thought it said... I still stick by most of this but the hp number is probably off.

Last edited by somebody5788; 03-31-08 at 11:56 AM.
Old 03-31-08, 11:56 AM
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Originally Posted by MX3
You are all against this yet none of you is really backing it up with a reason.
You are lowering the value and desirability of your FD. When you are done with a **** load of custom fabbing for big bucks, your FD will be worth less than if you just rebuilt your REW.


[/reason]
Old 03-31-08, 12:01 PM
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Originally Posted by somebody5788
You really want to go from 245 hp to like 120hp ? Miata's dont even get good enough gas mileage in the first place. Put that same engine in a slightly heavier car and your gas mileage may just not be there anymore. Sure the Miata's have a good engine and its got great power in a 2200lb car but its not something to put into an FD. If you want better gas mileage and for some reason dont want a Miata buy a Nissan 240sx.

PS: I just realized it was asking about a 1999 not a 1990 like i thought it said... I still stick by most of this but the hp number is probably off.
The 1999 Miata is a 130 HP.

In today's fuel market the FD3s is difficult to justify as a daily driver.

Putting a Miata can be made into a daily driver. Would'nt you agree?
Old 03-31-08, 12:03 PM
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all these guys are just haters. They hate when people put motors that come with 400hp stock into FD's.

Do what you want to do.
Old 03-31-08, 12:43 PM
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You all tell me from your own experience. Does'nt the FD3S RX-7 kill you wallet? Especially if you use it as a daily car?
Old 03-31-08, 01:53 PM
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Let's say it costs you 3-5k to do this swap. Why go through the trouble to just end up with an underpowered sports car when you could buy a Honda (as mentioned above) and use that as a daily for about the same price?

I'm open to swaps but there is no benefit at all to this. You would be better off doing an LS1 swap. It would probably be cheaper since there are kits made for it, and you would be looking at around 30mpg highway, especially if you went with a T-56.

I bet if you wanted to stay auto though you could sell your engine/trans and any mods for at least around 1.5-2k, and then invest 3-4k in an auto trans and an LS1 (or maybe even 1.5-2k for an LT1/auto in great shape), and then maybe another 2-3k in the mounting hardware and other associated goodies. That gives you a net input of 3-5k (2-3k for an LT1) and a reliable daily driver that is faster than what you had with better economy.

That's just me I suppose, but I'd be all for it if I could see a single benefit to the swap. However, I don't see any; I really don't even think you would see much of an improvement in fuel economy.

Another benefit is that V8 RX7's seem to hold their value relatively well. Where you would have the most undesirable FD in the US short of one that was wrecked you could end up with one that is worth more than yours currently is. I'm not trying to be mean but I don't want to see you waste your money. A well done V8 swap can sell for the sum of the parts (depending on what all was done), which usually isn't true for modified cars.

Last edited by Rexpelagi; 03-31-08 at 01:59 PM.
Old 03-31-08, 02:06 PM
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Originally Posted by MX3
You all tell me from your own experience. Does'nt the FD3S RX-7 kill you wallet? Especially if you use it as a daily car?
I think the main point everyone is trying to make is that you will be spending quite a bit of money on the custom install, fabrication, misc. other parts that you will need, converting certain sensors to work with the FD chassis(drivetrain/gauges, etc.). Bare minimum you are looking to spend thousands and thousands of dollars, and yet the 130 hp miata engine will only get OK gas mileage in a heavier chassis like a FD, as opposed to the miata.

After you have spent all of that money, you now have a car that is worth FAR less than it was to begin with, as it was with the 13B.

For example, lets say on the HIGH side you gain 10 mpg with the miata swap. At approx. $3.40 per gallon, you are only saving ~$18 per tank in a FD. Even if the swap ONLY costs you $5,000(which is likely WAY on the low side depending on fab work needed), it would take you 277 tanks of gas to break even, and that doesn't even account for the vehicle depreciation with the 4cyl!

At 1-2 tanks per week, it would take you between 3 and 5 years to BREAK EVEN! So at that point you haven't even saved yourself $1. Again, that is not even accounting for vehicle depreciation...
Old 03-31-08, 02:10 PM
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It would be easier and cheaper to buy a Miata for $1-3k and sell your car.
Old 03-31-08, 02:32 PM
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I shouldn't have to back this up, but I will. Your taking a slow economy engine and sticking it in a high level sports car. That's the most posuer thing you can do. You are completley to a "T" a ricer if you do that. Driving around in a fd sounding like a god damn honda. But w/e, not my car. Just don't pop your hood anywhere cause people will laugh and go...UH why? and youll be like "i'm poor so I put a miata 130hp pos in to this car so I could look like a super car but get the milage of a metro". There is nothing good you can say about it besides good gas milage. It just shows your a really cheap person trying to look like you have money or something just because as long as the car is running..then its an FD!
Old 03-31-08, 06:12 PM
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What??? putting an Miata engine in a FD....that's sacrilege!!! You have just trampled on some holy covenant RX-7 scriptures!

Nah, if you want to, that's your car. Let us know how it goes.
Old 03-31-08, 06:33 PM
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anyone know of a rwd trans that will mate to a Geo Metro 3 cylinder? i want to stick that in my FD and get awesome gas milage!
Old 03-31-08, 06:35 PM
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Yeah if you want to then do it. Screw what we say...I'll stick with the 13b. You bought your car and have every right to do what you want with it. I've learned there's too many people with different tastes for me to worry about what other people do to their cars...they will always do things I disagree with so I save myself the stress and just don't even bother judging cars anymore.
Old 03-31-08, 06:59 PM
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Originally Posted by RiceFx306
Yeah if you want to then do it. Screw what we say...I'll stick with the 13b. You bought your car and have every right to do what you want with it. I've learned there's too many people with different tastes for me to worry about what other people do to their cars...they will always do things I disagree with so I save myself the stress and just don't even bother judging cars anymore.
Thank You. I think this thread made a lot of people very emotional. Especially, FLYINN what's his name.

I do appreciate your email. You're a good man.


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