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Old 12-10-2010, 03:44 AM   #41
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good read, something to keep in mind... if i ever start to think about doing a v8 swap.
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Old 12-10-2010, 04:18 AM   #42
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Originally Posted by my97miata View Post
I say forget the LS swap and just build the engine that's in the car. Yeah, it won't be as powerful as a LS, but you should have alot of fun with it. I went for a ride in 2.0L stroked Miata (170 WHP) and a turbo with 250 WHP one, I enjoyed the ride in 2.0L more than I did the turbo version. Something about natural aspiration I find very appealling. I must add that the stroked out car had a very nice suspension. The trubo car had an aftermarket suspension also, but of a lesser quality. I fair that LS swap will through the balance off and your Miata won't quite be a Miata anymore. I said my piece.
There's an idea, I could go for 170 WHP!

j/k

I'll never go n/a in my Miata again (willfully) unless it makes more power than it does now. With a B6/BP, that's not happening.
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Old 12-10-2010, 04:19 AM   #43
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Originally Posted by SLVMX5 View Post
good read, something to keep in mind... if i ever start to think about doing a v8 swap.
intro thread, do it now!

Koto" by the time 2014 rolls around and you get to the point of starting the build, its possible that the v8 market for are cars will be a lil more saturated therefor hopefully resulting in lower prices...

Last edited by WonTon; 12-10-2010 at 04:46 AM.
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Old 12-10-2010, 12:00 PM   #44
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Originally Posted by fooger03 View Post
screw the car

invest in real estate
screw the estate

invest in real car

Quote:
Originally Posted by my97miata View Post
I say forget the LS swap and just build the engine that's in the car. Yeah, it won't be as powerful as a LS, but you should have alot of fun with it. I went for a ride in 2.0L stroked Miata (170 WHP) and a turbo with 250 WHP one, I enjoyed the ride in 2.0L more than I did the turbo version. Something about natural aspiration I find very appealling. I must add that the stroked out car had a very nice suspension. The trubo car had an aftermarket suspension also, but of a lesser quality. I fair that LS swap will through the balance off and your Miata won't quite be a Miata anymore. I said my piece.

I know why the 170hp felt better to you. Because you are a *****.




A daily driver is mandatory. My frame rail is the way it is because I had to rent a car while I was waiting for the right turbo parts to be sent to me and then I was rushed when trying to put the turbo in and didn't know what the **** I was doing.
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Old 12-10-2010, 01:40 PM   #45
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I hate to hijack the thread, but can you post pictures along with which bar was used? I'm thinking the 90-93 bar is shorter then the later year RB bars.
This is why it didn't take us 1000 hours.... we were working on the car, not taking pictures. I don't think we have any pictures of it, but it was in an 01 and we don't have any 01 RB bars laying around to compare to the 90-93 RB bar we have laying here.
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Old 12-10-2010, 01:43 PM   #46
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Originally Posted by crashnscar View Post
This is why it didn't take us 1000 hours.... we were working on the car, not taking pictures. I don't think we have any pictures of it, but it was in an 01 and we don't have any 01 RB bars laying around to compare to the 90-93 RB bar we have laying here.

Burn........

Understood. I guess most of us did it for the fun of building instead of the end result. Once done, the car was boring and is now set to the side collecting dust.
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Old 12-10-2010, 03:47 PM   #47
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Originally Posted by chpmnsws6 View Post
Burn........

Understood. I guess most of us did it for the fun of building instead of the end result. Once done, the car was boring and is now set to the side collecting dust.
Not meant to be insulting, just saying it would have taken longer if we were documenting everything step by step to teach other people. But we aren't.
Not sure why you think the car is boring though, is it because the power is linear instead of a jolt like a larger turbo provides as boost comes on?
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Old 12-10-2010, 06:51 PM   #48
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Basically. I also enjoy the build more then the end result of driving. Its fun to have the neck snapping torque, but it also makes it very twitchy. I'm also personally fighting cam surge around 1600-1800rpm. A stock engine with more cubes would probably be way more fun then the heavily cammed 5.3 where idle vacuum at 8-10 inches is considered normal.
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Old 12-10-2010, 10:51 PM   #49
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Originally Posted by kotomile View Post
The F20C is lightweight and sounds like a sportbike, and has a great transmission. The rotary isn't exactly lightweight, but is compact, and there's something about the sound of an aggressive bridgeport.
Lol. The F20C is lightweight and the rotary isn't... funny.
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Old 12-11-2010, 01:08 AM   #50
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Throw all of the peripherals on a rotary and tell me it's lightweight for its size, it's very "dense". It is nice to be able to keep its weight back and low, though.
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Old 12-11-2010, 01:18 AM   #51
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Originally Posted by kotomile View Post
Throw all of the peripherals on a rotary and tell me it's lightweight for its size, it's very "dense". It is nice to be able to keep its weight back and low, though.
Renesis Specs F20C Specs
Dressed Weight (lbs) 273 326
Max Power (hp) 260 @ 8,500 rpm 250 @ 8,300 rpm
Power/Weight (hp/lbs) 0.95 0.77
Specific Power (hp/lbs/1000rpm) 0.112 0.092
Max Torque 159 @ 5,500 153 @ 7,500
Torque/Weight (ft-lbs/lbs) 0.58 0.47

All accessories included. The normal 13b should weigh about the same as a Renesis, little more in the block, little less in accessories.

The 13b block, bare, weighs about 155 lbs, just to give you an idea of how light you can get with some aftermarket components.
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Old 12-11-2010, 01:31 AM   #52
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Originally Posted by chpmnsws6 View Post
Basically. I also enjoy the build more then the end result of driving. Its fun to have the neck snapping torque, but it also makes it very twitchy. I'm also personally fighting cam surge around 1600-1800rpm. A stock engine with more cubes would probably be way more fun then the heavily cammed 5.3 where idle vacuum at 8-10 inches is considered normal.
Get it professionally tuned. orion4096's 346ci car with 5.3 heads and a Comp 232-112 had really nasty cam surge under 2000rpm - a good tune (Rick at Synergy Motorsports) totally eradicated it. I was stunned at how much nicer the car drove after being properly tuned.
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Old 12-11-2010, 01:32 AM   #53
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Interesting. Nitpick - 13B will be heavier in accessories due to turbo(s), associated hardware, etc. n/a 13B would be lighter than turbo 13B, but I'm not going to bother with a rotary swap if it's not turbo.
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Old 12-11-2010, 01:48 AM   #54
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Originally Posted by kotomile View Post
Interesting. Nitpick - 13B will be heavier in accessories due to turbo(s), associated hardware, etc. n/a 13B would be lighter than turbo 13B, but I'm not going to bother with a rotary swap if it's not turbo.
Nitpick- The 13B is N/A.

The 13BT is Turbo.

The 13B can make 230whp pretty cheap N/A, on a streetport. So it'll last for about ever, drop a lot of weight from the front end, reduce CoG, reduce MoI by a lot. Can use the stock five speed, PPF and diff, so all you'd need is a V8 Roadsters subframe, weld engine mounts, wire and plumb it up. Exhaust and electronics would be the hardest part for me.
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Old 12-11-2010, 02:07 AM   #55
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Originally Posted by Savington View Post
Get it professionally tuned. orion4096's 346ci car with 5.3 heads and a Comp 232-112 had really nasty cam surge under 2000rpm - a good tune (Rick at Synergy Motorsports) totally eradicated it. I was stunned at how much nicer the car drove after being properly tuned.

On the initial base line tune, it was HORRID. The main issue is at 65mph, the car is only using 6-9% throttle (last time I logged it). Its getting better as I clean up the VE table and add timing (these engines seem to love timing down low). Rick is REALLY good at what he does though, so its no surprise he made the heavily cammed 5.3 drive great.

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Originally Posted by silicone boy View Post
Hate to break it to ya nixter, but as one of the few people who actually owns both engines and one of the only ones who has actually weighed an LS motor and the 13b-REW, I can tell you the rotary and its tranny weighs about 50 pounds more than the LS/T56. I have the pictures to prove it and I have posted them here within the last couple of weeks. It is actually the rotary that would throw off the handling, and rotary fans don't seem to want to believe it.

Yes, I could have put the FD's engine in my Miata, because I had to do something with it. I'm putting it instead in my Locost and I am finding, contrary to many people's beliefs, that it takes up a lot of physical space. The rotor housings themselves may be small, but when you add the air pump, turbos, and all the associated miles of plumbing that goes with it, well, it just adds up. I couldn't see adding 50 more pounds (and top heavy too...the rotary has a higher center of gravity) to the front than a more compact V8 motor.

The thing that the 13b-REW has going for it is that it makes half the power and gets half the gas mileage and you get to put a new one in every 35,000 or so when your apex seals get blown out under boost (ask me how I know)
Quoted from here:
http://forum.miata.net/vb/showpost.p...5&postcount=20

Don't kill the messengers, but I feel his word his highly reliable. Many women would agree
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Old 12-11-2010, 04:11 AM   #56
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Originally Posted by chpmnsws6 View Post
Quoted from here:
http://forum.miata.net/vb/showpost.p...5&postcount=20

Don't kill the messengers, but I feel his word his highly reliable. Many women would agree
I don't even know where to begin on that. -.-

Let's just show some pictures, so I don't just type.



The engine is very bottom heavy. Accesories are mounted high, but they take up much less weight than an actual block.



Put on an aftermarket intake (or webers, as shown) and you can see just how low it actually sits.



That gives you an idea of just how far back it can sit. Compared to a V8 you can get a /lot/ more frontal room.

Ok, another view, here's a bare block in an FC RX7.



See how it's entirely behind the steering rack? You can even see the rack looking straight down.

Name:  engine.jpg
Views: 518
Size:  78.3 KB

Now here's an FC LS1 swap. See how about half the engine is in front of the shock towers? Compare that to the 13b which sits almost entirely behind them.

So we've covered CoG an MoI. Two pluses for the 13B.

Now, if you pull out a 13B-REW, with twin turbos, big cast exhaust manifold fol all that, you look like this:



Basicly, an utter mess. If you want the FD to be reliable, you pretty much rip out the stock cooling and turbocharging system and start over. Then you get a good tune. Tuning is more difficult than it sounds, many tuners will say they can do a rotary, but few actually know how. And there's actually an engine under there. Somewhere.

But turbo rotaries don't interest me. A good street port, intake, exhaust and tune on a 13b can make 230whp and last 150,000 miles before a rebuild. Putting in a N/A rotary in a Miata takes 80 lbs off the front and improves handling drasticly. Weight is much lower, much further back, and there's considerably less of it to begin with.

Weight:

LS1 V8 n/a 480lbs. The motor mounts = 12 lbs
Mazda rotary 2 rotor, 285lbs
http://www.funco-motorsports.com/motor_weights.htm

Now look at this post, by silicone boy: http://forum.miata.net/vb/showpost.p...94&postcount=9

B6 weight: 407
13B-REW weight: 534

That's with transmission. So the B6 engine will have the five speed we're all used to. The REW will have the five speed good for about 600 wheel torque.

The B6 will have an exhaust manifold and a turbo. The REW will have two turbos, a cast iron manifold, two wastegates, two downpipes... a twin turbo setup.

There's no information if the B6 had AC or power steering, but the REW has both.

There's no information if they're full of fluids or not. There's no picture showing if they're actually in the same condition.

The best thing I have to say about the 13B-REW is that it came in a nice car.

It's a heavy, complex, not fully developed motor, at least when we had it in the US. I'm not sure if they had it done in japan by 1999... but it doesn't really matter.

I will say the 13B swap is very appealing to me though. Compared to a turbo BP and depending on accessories, it would take 80-120 lbs off the front end, and move the weight way down and back. That's the data proving it, above.
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Old 12-11-2010, 04:38 AM   #57
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I would love a would love a 230whp k20 swap. I have a 08 SI and a 06 S2K, I prefer the K20.
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Old 12-11-2010, 10:46 AM   #58
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Originally Posted by chpmnsws6 View Post
Basically. I also enjoy the build more then the end result of driving. Its fun to have the neck snapping torque, but it also makes it very twitchy. I'm also personally fighting cam surge around 1600-1800rpm. A stock engine with more cubes would probably be way more fun then the heavily cammed 5.3 where idle vacuum at 8-10 inches is considered normal.
What engine management do you have? Can't work on the timing map help with cam surge?
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Old 12-11-2010, 12:17 PM   #59
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What engine management do you have? Can't work on the timing map help with cam surge?
It should be the stock computer and then he's using HP tuners. If he's smart.
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Old 12-11-2010, 04:36 PM   #60
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Originally Posted by Nagase View Post
The 13B can make 230whp pretty cheap N/A, on a streetport. So it'll last for about ever, drop a lot of weight from the front end, reduce CoG, reduce MoI by a lot. Can use the stock five speed, PPF and diff, so all you'd need is a V8 Roadsters subframe, weld engine mounts, wire and plumb it up. Exhaust and electronics would be the hardest part for me.
Really?

Not a bolt-up is it?

Is there a kit for this?
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