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      06-26-2015, 04:40 PM   #1
VintageFD
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Rx-7 Rotary vs V8

Had my FD reviewed by Matt some time ago as he compared it to another nicely built LS2 (bored/stroked cammed) FD. Although I really dont think he did a good job comparing the two at all, the video is still cool especially for those not familiar to rotaries. I wish he talked about the feel, powerband and sheer vibe BOTH cars gave.

My car had its twin wastegates open to the atmosphore so it sounded way too loud and raspy. Now its re-routed and sounds sweet.


Track video w/ re-routed wastegates






Car details and pictures
https://www.wheelwell.com/profile/55...8b2786a/specs/


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      06-27-2015, 06:47 PM   #2
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FD is such a sweet car plagued by such an awful motor.

I'd be willing to bet there are a higher percentage of FD's with motor swaps from a different manufacturer than any other regular production car out there.
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      06-27-2015, 07:28 PM   #3
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Quote:
Originally Posted by Nitrousbird View Post
FD is such a sweet car plagued by such an awful motor.

I'd be willing to bet there are a higher percentage of FD's with motor swaps from a different manufacturer than any other regular production car out there.
doubt it
240zx
240sx

now those were cars with terrible stock motors
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      06-28-2015, 08:42 AM   #4
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Quote:
Originally Posted by Nitrousbird View Post
FD is such a sweet car plagued by such an awful motor.

I'd be willing to bet there are a higher percentage of FD's with motor swaps from a different manufacturer than any other regular production car out there.

I beg to differ. Its a great engine that sounds and feels like nothing else. Its not the only engine I appreciate but its up there. Not for everyone, I admit.

Funny thing is my FD has been more reliable than my M5 and both get the same MPG.

Here is a cool audio comparo from the shoot
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      06-28-2015, 09:31 AM   #5
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Quote:
Originally Posted by pikkagtr View Post
doubt it
240zx
240sx

now those were cars with terrible stock motors
And most motor swaps for those cars are another Nissan motor, which is the same manufacturer.

When people yank the rotary out of an FD, they aren't going to the Mazda parts bin for a replacement, which was the point of my original post.
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Originally Posted by VintageFD View Post
I beg to differ. Its a great engine that sounds and feels like nothing else. Its not the only engine I appreciate but its up there. Not for everyone, I admit.

Funny thing is my FD has been more reliable than my M5 and both get the same MPG.
- Poor fuel mileage (think how much heavier your M5 is yet get the same fuel mileage)
- Drinks oil
- Well known for eating apex seals and destroying the motor. It's hard to find an RX7 with over 50k on the original rotary
- Lack of torque
- One of the worst sounding engines out there
- Have to ring the crap out of it to make power, but doesn't even make power at that high of an RPM, especially for such a small motor.

I've never understood the advantage of the rotary, other than to be different.
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      06-28-2015, 09:46 AM   #6
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Quote:
Originally Posted by Nitrousbird View Post
And most motor swaps for those cars are another Nissan motor, which is the same manufacturer.

When people yank the rotary out of an FD, they aren't going to the Mazda parts bin for a replacement, which was the point of my original post.

- Poor fuel mileage (think how much heavier your M5 is yet get the same fuel mileage)
- Drinks oil
- Well known for eating apex seals and destroying the motor. It's hard to find an RX7 with over 50k on the original rotary
- Lack of torque
- One of the worst sounding engines out there
- Have to ring the crap out of it to make power, but doesn't even make power at that high of an RPM, especially for such a small motor.

I've never understood the advantage of the rotary, other than to be different.

-Ive never popped a apex seal with over 9 years of ownership and 7 years of hard track work.
-My M5 drinks more oil than the FD. Plus, its not such a big deal to be a shot of oil ever 3 fillups?
-My car makes 320wtq in the midrange. Sees 15psi by 2800rpm and makes 420whp from 6-8.5krpm. Ill share a dynograph later however its no secret that such a powerband is ideal especially the boost response with a large 600whp capable turbo. You dont want monster tq in a track car.
-MPG as long as its not horrendous who cares. Buy a diesel 3 series a DD and call it a day.


But to each there own.
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      06-28-2015, 12:26 PM   #7
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Eh, I'm a big RX7 guy, as you can tell by my name, and I don't understand why people bother with LSX swaps. But I would never claim that the rotary is a better engine than a performance minded piston engine. I love them because of their uniqueness, but that's about it. Your car is beautiful though. And you should be buying lottery tickets if you haven't blown any apex seals yet. Your experience is definitely not common there, nor is your oil consumption (although I'm surprised you aren't running premix esp for a track car)

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      06-29-2015, 12:28 AM   #8
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Quote:
Originally Posted by fcman View Post
Eh, I'm a big RX7 guy, as you can tell by my name, and I don't understand why people bother with LSX swaps. But I would never claim that the rotary is a better engine than a performance minded piston engine. I love them because of their uniqueness, but that's about it. Your car is beautiful though. And you should be buying lottery tickets if you haven't blown any apex seals yet. Your experience is definitely not common there, nor is your oil consumption (although I'm surprised you aren't running premix esp for a track car)
I agree, its silly to claim a rotary is better than a piston engine, especially modern ones. I am not sure why Matt brought that up in the video. Rotaries are just different fun/sporty engines which I believe suits the Rx-7 perfectly. I do indeed premix and also "refurbished" the motor last year since it was original from 1993 and I had the time. Just changed the seals, ported it and closed it back up for a minimal cost. When I did open the engine, the internals looked fantastic btw. Tuning is everything.
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      06-29-2015, 08:59 AM   #9
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Quote:
Originally Posted by VintageFD View Post
I agree, its silly to claim a rotary is better than a piston engine, especially modern ones. I am not sure why Matt brought that up in the video. Rotaries are just different fun/sporty engines which I believe suits the Rx-7 perfectly. I do indeed premix and also "refurbished" the motor last year since it was original from 1993 and I had the time. Just changed the seals, ported it and closed it back up for a minimal cost. When I did open the engine, the internals looked fantastic btw. Tuning is everything.
First time I blew mine the housings were visibly warped, it was like a bunch of rolling hills lol, not good. Good luck with your car, I'm looking at picking up another soon, but it's getting to the point where 2nd gens in good shape are creeping up to 3rd gen prices, people are just beating the living hell out of them
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      06-29-2015, 11:29 AM   #10
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Swapping out for a LSx engine is simple. Install a LS1, LS6 or LS2 and find out how easily it can be upgraded for more power or just awesome reliability. Even putting in a 5.3 V8 (ones that the Silverado uses) can be had for $500 (ready to drop in), can make an absurd amount of power with nothing done to it internally other than a cam swap or leave it alone and not worry about it crapping out on you.

LSx engines do eat oil, like most engines do but they are very reliable and are easy to work on. Those are the key points, reliability and easy to work on.
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      06-29-2015, 12:50 PM   #11
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Quote:
Originally Posted by Vigilante375 View Post
Swapping out for a LSx engine is simple. Install a LS1, LS6 or LS2 and find out how easily it can be upgraded for more power or just awesome reliability. Even putting in a 5.3 V8 (ones that the Silverado uses) can be had for $500 (ready to drop in), can make an absurd amount of power with nothing done to it internally other than a cam swap or leave it alone and not worry about it crapping out on you.

LSx engines do eat oil, like most engines do but they are very reliable and are easy to work on. Those are the key points, reliability and easy to work on.
But why bother buying an RX7 if you want an LSX powered car? Just buy a Corvette... Hell it's cheaper to pick up a C5 Z06.
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      06-29-2015, 01:38 PM   #12
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Curious what the LSx does to weight balance and Cg, the two best parts of the FD. I know the wankel isn't all that light, but it's low.
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      06-29-2015, 03:15 PM   #13
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But why bother buying an RX7 if you want an LSX powered car? Just buy a Corvette... Hell it's cheaper to pick up a C5 Z06.
And the RX7 weighs a lot less too even after swapping over to a V8 no? Its nice to have something different and since they have been doing this for years, why not?

Quote:
Originally Posted by Red Bread View Post
Curious what the LSx does to weight balance and Cg, the two best parts of the FD. I know the wankel isn't all that light, but it's low.
I think the LS1 actually gives the RX7 a 50/50 balance but a LS1 weighs like 450 lbs with the trans.
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      06-29-2015, 03:18 PM   #14
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And the RX7 weighs a lot less too even after swapping over to a V8 no? Its nice to have something different and since they have been doing this for years, why not?
Yeah it does, but my question is why buy an RX7? They are ridiculously expensive in good shape, way more expensive than the chassis is worth (ie you can do much better than a 93 mazda chassis). So why buy one if you aren't interested in the rotary motor? If you just want a small light car to throw an LS1 in there are much better options out there.
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      06-29-2015, 04:43 PM   #15
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But a stock FD had a more favorable 45f/55r balance. FD's were extremely capable chassis, over 1.0g stock on twenty year old tires, this nonsense about better chassis's available is just that.
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      06-30-2015, 01:05 AM   #16
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Quote:
Originally Posted by Vigilante375 View Post
Swapping out for a LSx engine is simple. Install a LS1, LS6 or LS2 and find out how easily it can be upgraded for more power or just awesome reliability. Even putting in a 5.3 V8 (ones that the Silverado uses) can be had for $500 (ready to drop in), can make an absurd amount of power with nothing done to it internally other than a cam swap or leave it alone and not worry about it crapping out on you.

LSx engines do eat oil, like most engines do but they are very reliable and are easy to work on. Those are the key points, reliability and easy to work on.
Hmm, I put 50K on my LS3 (just sold it) and never noticed it using ANY more oil than it was filled up to at the oil change. Can't say the same about my subaru, that thing blew some oil for sure, wasn't excessive, but was far from zero.
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      06-30-2015, 03:04 AM   #17
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Hmm, I put 50K on my LS3 (just sold it) and never noticed it using ANY more oil than it was filled up to at the oil change. Can't say the same about my subaru, that thing blew some oil for sure, wasn't excessive, but was far from zero.
Exactly. The LM7 (5.3L) in my truck I've had for 10 years still doesn't burn any at 165k on the clock...and it hasn't exactly led a pampered life. LS1 in our boat doesn't burn any either and that sees a much more abusive load than any street car.
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      06-30-2015, 06:36 AM   #18
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'99 5.3 in my Sierra is at 197k miles, runs strong, no oil burning. NOTHING other than regular half assed maintenance. The exhaust manifolds are starting to rust through at the bolts resulting in a small exhaust leak.

honestly when that gets too bad I may pull the motor and have some fun with it before it goes back in
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      06-30-2015, 09:49 AM   #19
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Quote:
Originally Posted by Red Bread View Post
But a stock FD had a more favorable 45f/55r balance. FD's were extremely capable chassis, over 1.0g stock on twenty year old tires, this nonsense about better chassis's available is just that.
If you buy a 20+ year old car expecting the chassis to perform like it did in 1993, you're going to have a bad time. Unless you're going to be seam welding the chassis, which a lot of people do when they perform V8 swaps. Have you driven a 20 year old FD?
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      06-30-2015, 09:51 AM   #20
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Yep, my dad has a bone stock 93 with 90k miles. Even still has it on the same, but new, Bridgestone S02's. I'd buy one over a lot of modern sports cars, it's so much more direct and precise, even with it's rotting old 22 year old frame.
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      06-30-2015, 11:28 AM   #21
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Quote:
Originally Posted by JamesNoBrakes View Post
Hmm, I put 50K on my LS3 (just sold it) and never noticed it using ANY more oil than it was filled up to at the oil change. Can't say the same about my subaru, that thing blew some oil for sure, wasn't excessive, but was far from zero.
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Exactly. The LM7 (5.3L) in my truck I've had for 10 years still doesn't burn any at 165k on the clock...and it hasn't exactly led a pampered life. LS1 in our boat doesn't burn any either and that sees a much more abusive load than any street car.
Had a 02 Trans Am and it was a less than it was when I changed the oil. Same for my 06 GTO with the LS2. Both were modded and 6 speed's; cam, full exhaust, air intake, tuned. They were DD and driven fairly hard. The things I've read over the years is those GM engines do consume oil a bit. They even have a service bulletin for dealers about it.

Can't say much on the old 5.3 as I've never had a Silverado.
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      07-01-2015, 10:06 AM   #22
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People who talk shit about rotaries are ones who have no experience with them. Yeah gas mileage and oil consumption royally sucks but the apex seal thing is blown way out of proportion because for most people that's the only thing they "know" about rotaries. They're really not that hard to work on.

I hate LS swapped FDs more than anything else on the road.
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