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Having second thoughts on LS swap.

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Old 12-11-2010, 03:40 PM
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Originally Posted by gospeed81
Really?

Not a bolt-up is it?

Is there a kit for this?
Not a kit, it's simple.

The five speed the miata uses...

Is from the FC RX7.

Swap bellhousings and it's suddenly a miata transmission in the rear, RX7 transmission in the front.

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Old 12-11-2010, 03:44 PM
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Originally Posted by Nagase
Not a kit, it's simple.

The five speed the miata uses...

Is from the FC RX7.

Swap bellhousings and it's suddenly a miata transmission in the rear, RX7 transmission in the front.


Wow...I would have never imagined this due to all the hassle using the TII tranny is.

Basically replacing or fabricating the rest of the driveline is the main thing that has kept me away from every motor swap.

I could totally dig a 200+whp n/a rotary swap.
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Old 12-11-2010, 03:51 PM
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Originally Posted by gospeed81
Wow...I would have never imagined this due to all the hassle using the TII tranny is.

Basically replacing or fabricating the rest of the driveline is the main thing that has kept me away from every motor swap.

I could totally dig a 200+whp n/a rotary swap.
Yep! Did you know our rear differential is from an FC RX7 as well?

So really, all the fab work is done except motor mounts, and that's the easy part.

Then exhaust, wiring, coolant tubes and you're done.
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Old 12-11-2010, 04:26 PM
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Originally Posted by hustler
I am not sure I get the V8 swap thing because it's not very appealing to me. Will you have significantly more fun in a V8 Miata over a 250 or 300whp 4-slugger? This could be my extreme disdain for troglodyte V8 swap recommendations for laymen and fanboys.
This is my favorite post so far. I could not agree more. Sure the LS/V8 swaps are really cool, but I know I would have have more fun with my four-banger any day. Sure there is more maintenance, up keep and what not with the turbo motor, but to me, that is half of the fun. I love being able to diagnose any problem that the car could have because I KNOW where everything is and how I put the car together.

But to each their own, no shame in owning either. Turbos sounds better though

Originally Posted by Nagase
Yep! Did you know our rear differential is from an FC RX7 as well?
So really, all the fab work is done except motor mounts, and that's the easy part.
Then exhaust, wiring, coolant tubes and you're done.
Geez Erin, just get a rotary please....
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Old 12-11-2010, 04:28 PM
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Originally Posted by viperormiata
Geez Erin, just get a rotary please....
Do the wiring for me? :(

Wiring scares me.
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Old 12-11-2010, 04:41 PM
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Originally Posted by scottyd
It should be the stock computer and then he's using HP tuners. If he's smart.
Correct. I have been adjusting the timing table, but because I have a junk 99-00 pcm, I can't use real time tuning. This makes tuning take forever. Being in the nursing program and never getting a chance to take a good drive also makes tuning take forever.

Originally Posted by viperormiata
I love being able to diagnose any problem that the car could have because I KNOW where everything is and how I put the car together.

But to each their own, no shame in owning either. Turbos sounds better though
This is one of the biggest reasons I pulled out the Turbo4. LS's are a breeze to work on while the 4cyl T was foreign.

Originally Posted by Nagase
Do the wiring for me? :(

Wiring scares me.
Once you sit down and map it out, Mazda wiring diagrams aren't that bad.

The NA FC differential might be the same as the 94+ Miata's, but the center chunk is not. The FC center chunks are about 10 feet long, while the Miata/FDRX7/929 center chunks are fairly short. The side benefit to the 929 center chunk is a 3.7 gear and SIMPLE install. It fits like a glove.
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Old 12-11-2010, 04:51 PM
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Originally Posted by chpmnsws6
Once you sit down and map it out, Mazda wiring diagrams aren't that bad.

The NA FC differential might be the same as the 94+ Miata's, but the center chunk is not. The FC center chunks are about 10 feet long, while the Miata/FDRX7/929 center chunks are fairly short. The side benefit to the 929 center chunk is a 3.7 gear and SIMPLE install. It fits like a glove.
Did you use the Miata harness for your install or the LS harness?

Yeah, I know some of the parts are different, but it's still the same guts. Just like how the FC transmission has a different housing.
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Old 12-11-2010, 05:03 PM
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Originally Posted by chpmnsws6
This is one of the biggest reasons I pulled out the Turbo4. LS's are a breeze to work on while the 4cyl T was foreign.
I guess it's just a difference of backgrounds and preferences. I love working on 4 and 6 cylinder motors (turbos are a added bonus). Anything "V" makes me nervous as hell to work on, lol. The only "V" motor I ever work on is with the vipers, but after so many years it just becomes easier( not easy, just easier).

But like I mentioned earlier, to each their own.
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Old 12-13-2010, 02:33 PM
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Originally Posted by viperormiata
I love being able to diagnose any problem that the car could have because I KNOW where everything is and how I put the car together.

But to each their own, no shame in owning either. Turbos sounds better though
I'm not sure why you'd think someone who did their own V8 swap wouldn't know every in and out of their car. Face it, it takes about 5 hours to turbo a Miata. And based on all of the retarded questions from newbs with turbos, I'd argue that the % of owners being able to diagnose any problem because they KNOW where everything is greatly sides with the V8 swappers.
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Old 12-13-2010, 03:24 PM
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Originally Posted by fmowry
I'm not sure why you'd think someone who did their own V8 swap wouldn't know every in and out of their car. Face it, it takes about 5 hours to turbo a Miata. And based on all of the retarded questions from newbs with turbos, I'd argue that the % of owners being able to diagnose any problem because they KNOW where everything is greatly sides with the V8 swappers.
I have to disagree. Swapping in a motor has nothing to do with the mechanics of the motor and how to diagnose a problem that motor could have. Besides, I was talking about my own experience. I built everything from the ground up and restored my car over a 2-1/2 year period. I personally have been through every inch of my car (probably why I came off as being so pompous, sorry for that.)

Yeah it can take less than a day to turbo a miata, but that is completely off the subject of what I was talking about. But, you do make a valid point, there are a lot of noobs than can barely handle a Greddy install, much less a V8 conversion and their knowledge of the car would more than likely be less than a V8 swapper.
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Old 12-14-2010, 04:29 AM
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The brother-in-law and I are kicking around some ways to spend my LS budget on non-LS stuff. He may have a hookup with some body guys, hmm...I've been wanting to do a color change to GT3 RS green for some time now.

Color change would be just if there's enough cash left, but I for sure want to upgrade the brakes, some "thermal management" to keep the interior cool, and some interior improvements (my interior looks like ***). If I do the color change, there's some slight bodywork to take care of on the LR corner.
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Old 12-14-2010, 07:20 AM
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I could probably name 100 better ways to spend my LS budget on non-LS stuff. But then I'd have to be realistic on how much I've spent. Who knows when my wife will some day become computer savvy and find all of my postings on how much I've spent (not to mention how much **** I watch).
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Old 12-14-2010, 07:49 AM
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Originally Posted by fmowry
Who knows when my wife will some day become computer savvy and find all of my postings on how much I've spent (not to mention how much **** I watch).
mt.net quote of the month



But yeah, while I love the LSx idea...there are a LOT of other things you could do with that much time and money.
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Old 12-14-2010, 02:57 PM
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Originally Posted by fmowry
I could probably name 100 better ways to spend my LS budget on non-LS stuff.
Non-LS Miata stuff? I'm open to suggestions.

Oh and add poly bushings to the list. Must get done.
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Old 12-14-2010, 05:51 PM
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House, land, or gold
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Old 12-14-2010, 11:25 PM
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id just put a stock s2k engine in it with a kpro ems and you will make like 240hp and have the reliability of a stock s2k which = breaks never, you will ave more gas mileage then a stock s2k more even then a stock miata.i really dont see the down side to the f20c compared to the rotary. cant weigh much more if any and makes more power then a nice to drive on the street rotary would and has more reliability and less fuel consumption. its pretty much ls1 or f20c if your set on ditching the miata powerplant.
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Old 12-14-2010, 11:29 PM
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Originally Posted by 1slowna
id just put a stock s2k engine in it with a kpro ems and you will make like 240hp and have the reliability of a stock s2k which = breaks never, you will ave more gas mileage then a stock s2k more even then a stock miata.i really dont see the down side to the f20c compared to the rotary. cant weigh much more if any and makes more power then a nice to drive on the street rotary would and has more reliability and less fuel consumption. its pretty much ls1 or f20c if your set on ditching the miata powerplant.
s2k gets shitty gas mileage stock..
Do you always just pull "facts" out of your ***?
Go on s2ki and look at what people are getting gas mileage wise: 22-24.
That's horrible for a 2 liter four banger.
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Old 12-14-2010, 11:30 PM
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Originally Posted by 1slowna
id just put a stock s2k engine in it with a kpro ems and you will make like 240hp and have the reliability of a stock s2k which = breaks never, you will ave more gas mileage then a stock s2k more even then a stock miata.i really dont see the down side to the f20c compared to the rotary. cant weigh much more if any and makes more power then a nice to drive on the street rotary would and has more reliability and less fuel consumption. its pretty much ls1 or f20c if your set on ditching the miata powerplant.
It weighs 400lbs fully dressed with transmission, about the same or a little more than a BP.

Has a higher center of gravity, is longer.

Adds power, yes. Reduces weight, no. If you're about the power, get a V8, not reason not to when swapping engines.
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Old 12-14-2010, 11:53 PM
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Originally Posted by 18psi
s2k gets shitty gas mileage stock..
Do you always just pull "facts" out of your ***?
Go on s2ki and look at what people are getting gas mileage wise: 22-24.
That's horrible for a 2 liter four banger.
This is true. I was very surprised when my friend told me what his mileage was in his S2K.

But what has always turned me off about the S2K motor swap was the extreme lack of torque.http://flyinmiata.com/tech/dyno_runs/FM99TvsS2000.pdf
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Old 12-15-2010, 03:13 AM
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Originally Posted by chpmnsws6
House, land, or gold
Already have the first two.
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