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 Post subject: Where's the LFX love?
PostPosted: February 29, 2020, 5:14 pm 
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The motors are cheap, come with manual transmissions, put out over 300 HP stock, weigh less than a Miata motor, and have integral exhaust manifolds. What's not to like?

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PostPosted: February 29, 2020, 6:37 pm 
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"What's not to like?"

Well, the integral exhaust manifolds for one! As an old hot-rodder, one of the first things you do in a mod job is to install a nice looking set of headers!!! Other than that, sounded great. I have an LFW 3.0 in my D/D and that little engine IS impressive!

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PostPosted: February 29, 2020, 8:39 pm 
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https://grassrootsmotorsports.com/project-cars/1996-mazda-miata/project-endurance-miata-fitting-our-lfx-v6/

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PostPosted: February 29, 2020, 11:47 pm 
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Trans is really wide. I tried an LTG and it was too wide and tall.


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PostPosted: March 1, 2020, 12:52 am 
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ngpmike wrote:
"What's not to like?"

Well, the integral exhaust manifolds for one! As an old hot-rodder, one of the first things you do in a mod job is to install a nice looking set of headers!!! Other than that, sounded great. I have an LFW 3.0 in my D/D and that little engine IS impressive!


Meh, exhaust manifolds are always getting in the way. Anything that cleans up the engine bay in this manner is ok by me.


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PostPosted: March 1, 2020, 1:56 pm 
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KB58 wrote:


Here's another: A practically stock LFX in a 1st generation Miata becoming one of the fastest production based track cars in the country:
https://www.mazdatalkforum.com/viewtopi ... =10&t=3528

We're talking about going up against cars sometimes producing 600-1000 HP and winning in most cases.
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PostPosted: March 2, 2020, 10:02 am 
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kreb wrote:
The motors are cheap,


I can't find a working one on car-part.com for less than $1200.

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come with manual transmissions,


Those do appear cheap, starting at $400ish.

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weigh less than a Miata motor,


GRM says that it weighs ~the same as their iron-block turbo Miata setup. So it'd weigh more than a stock non-turbo B-engine, and way more than an all-aluminum MZR.

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What's not to like?


Direct injection severely limits your aftermarket fuel injection options, generally locking you into the factory ECU and just about requiring the use of a professional tuner ($$$) to adjust stuff.

As an alternative, I'll offer up the Mustang's 3.7L V6. car-part had 3 pages of Camaro LFX V6 engines. They have 39 pages of Mustang V6 engines. As such, you can get a good, running, low mileage version for under $400. Six speeds are similarly cheap. Standard port injection means you can toss on any aftermarket ECU that can handle the four channel Ti-VCT and you're golden. The Mustang makes the same torque as the Camaro (280ft-lb). A tune (since it's easy with port injection) will get you a 20hp gain, matching the Camaro's hp figure.

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PostPosted: March 2, 2020, 10:46 am 
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Concerning an LFX conversion, how is it better than going with an LS3 V8. Lighter, I assume, but probably not by much. I only bring it up due to the enormous market support for the LS3, and that the larger engine would presumably be more reliable due to not working as hard.

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PostPosted: March 2, 2020, 12:22 pm 
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Good points. There are tons of LFX motors out there, but most are lower HP versions. By the time you add the transmission and diff, it's going to be heavier than the Miata. But at least the weight is low and further aft. RE engine management, I think that HP Tuners will get you in there fairly easily, but the direct injection? Well yeah.

Mustang 3.7? Not a bad idea. They've had a lot of success racing that motor, so it should be pretty stout. And if it isn't powerful enough, presumably the turbo versions are out there to bolt in.....

Why not just go LSX? I've heard of oiling issues, but other than that and the extra 80 lbs, it does make a lot of sense. I suppose it's partly what interests you. Halfway through one of the threads that I linked to, someone jumps in with "You should have just gone with a stroker K24!"


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PostPosted: March 2, 2020, 1:37 pm 
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Valid point on the LSX oiling, my brother added a dry sump for that very reason. Seems to be enough corner-related failures of Corvettes to indicate that it's true.

Regarding the "just use a modified K24", yeah well... I learned the hard way that building a K24 the right way costs way more that a brand new LS3. It's made enough of an impression on me that:

1. It makes me scared to really push it for fear of spending more fixing it.
2. I'm thinking about the next project, which will likely use an LS3 or new gen LT1 engine.

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PostPosted: March 2, 2020, 4:57 pm 
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KB58 wrote:
Concerning an LFX conversion, how is it better than going with an LS3 V8. Lighter, I assume, but probably not by much.


The LS is heavier, and with more weight pushed forward. And with Goodwin Racing setting lap records by multiple seconds - do you think he'd add ANY amount of weight in an effort to get a few more hp?

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PostPosted: March 2, 2020, 6:42 pm 
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Laminar wrote:
KB58 wrote:
Concerning an LFX conversion, how is it better than going with an LS3 V8. Lighter, I assume, but probably not by much.


The LS is heavier, and with more weight pushed forward. And with Goodwin Racing setting lap records by multiple seconds - do you think he'd add ANY amount of weight in an effort to get a few more hp?


Yeah, but he's upping the ante with a supercharger and intercooler, so that's got to eat into the weight differential some. He's gone through a couple of transmissions too, which makes me wonder if the Gertrag is going to hold up, or if he'll need to adapt a (heavy) t56. There's the chance that Like Kurt, he'll end up saying "Wow, I could have had a V8!"


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PostPosted: March 4, 2020, 5:26 pm 
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kreb wrote:
Yeah, but he's upping the ante with a supercharger and intercooler, so that's got to eat into the weight differential some. He's gone through a couple of transmissions too, which makes me wonder if the Gertrag is going to hold up, or if he'll need to adapt a (heavy) t56. There's the chance that Like Kurt, he'll end up saying "Wow, I could have had a V8!"


At $400 a pop from the junkyard, he could go through 7 of them before he gets to the cost of a new T56, or at least four of them for the cost of a used T56. Weight is about the same, I think he said it was in the neighborhood of 130lbs, which is what a T56 weighs.

His first trans was broken from the junkyard with a seized pivot, his second was chewed up due to grinding gears because his original flywheel was incorrectly machined so the clutch release was overtraveling. None of the failures have been pure race-related.

No $1200 stock-long-block LS is going to give you 400whp (he claims more whp than an F430, which dyno over 400whp). An LS2 will get you about 360whp. An LS3 might be above 400whp, but that's a $5000+ engine, used.

I feel like there's some benefit in running a factory sealed long block that can be slammed in place. No cam swap, no head swap, no messing around. You get factory tolerances, factory tune, and factory build quality.

I'd bet he's got a better hp:weight:dollar:reliability ratio with a $1200 long block and $2000 supercharger than he would with an LS-based combo.

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PostPosted: March 4, 2020, 6:54 pm 
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Well the irony is that after years of trying to make the Miata turbo reliable, he goes with the LFX to instant success. Now it's almost like he's doing the same thing again, making the very reliable LFX less so - and doing a truly epic shoehorn job getting the supercharger and intercooler in there. Not to knock Ryan or the LFX. It's his baby and he can feed it any sort of formula he wants.


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PostPosted: March 5, 2020, 1:24 am 
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Laminar wrote:
...At $400 a pop from the junkyard, he could go through 7 of them before he gets to the cost of a new T56, or at least four of them for the cost of a used T56...

But now throw in the wasted gas, food, motel, and entry fee to that cheap price and it may lose some of its attraction.

I've heard this same reasoning to rationalize not getting a dry sump. Same thing applies, that after a few failures, the low price looks less so.

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