My Miata diff has been through 15 Miata transmissions both 5 and 6 speeds and never had an issue. With around 300 ft-lbs of torque It puts down lap times ~10 second under the spec Miata lap record on many tracks. Also holds up with the grip level of 275 Hoosier A6 for Autocross. There might be some good reasons to go away from a Miata diff but in my experience strength or reliability is not one of them.

Now I think there may be some factors with ratios at play I am theorizing that a 3.636 rear end ratio is going to be easier on a diff than say a 4.778 but the opposite is true for the transmission.

 

Took a lot longer than expected but the clutch and flywheel specs/measurements are finally finalized finally. Protos are paid for and in the works now, 4-6 weeks out.

 

I decided to hop on this bandwagon too and picked my LFX engine set up a couple weeks ago. My plan is to do the swap over this winter and have it on the road in the spring. I'm looking forward to seeing how the other builds are coming along.

So is this going to be a production clutch/flywheel combo is just a one off setup for your car?

 

I guess I lost the plot at some point... why do you need a custom flywheel/clutch? Are you using a transmission which wasn't originally behind a LFX engine? Since the Camaro offers the LFX + 6spd manual transmission, one would think that OEM and/or aftermarket options would be available? (I admit that I am not entirely clear which of the "MX" manual transmissions are used by GM with the LFX vs those MX transmissions from different applications like the Ecotech 4cyl engines.)

Thanks

 

The factory clutch and flywheel total out to over 50 lbs. That's not going in my car if you paid me

There are very few clutch options in the aftermarket. Because the factory setup uses a flex plate, to switch to an aftermarket clutch you also need to change to a new flywheel made by the same company as the clutch. So if you find you don't like the clutch from that brand, changing is going to be a bigger investment as you need to toss out the flywheel as well. This means I don't want to take a gamble on the few options that already exist and none of them check all the boxes I'd like anyways.

So we're working with SpeedSport on a carbon/carbon clutch and flywheel that does check all the boxes. Should be good for way more torque and heat than the factory clutch with much less rotational mass yet similar to stock pedal feel and easy to drive.

It will be a production part once we've finalized a few details after testing.

 

Thanks, that makes sense. There are some high HP V6 LFX Camaro's out there, but they are probably more drag focused than road course/street, which would translate to not having suitable clutch setups "on the shelf" for Miata LFX swaps.

Any idea of the target cost for the carbon/carbon flywheel and clutch setup? Are we talking $1k-$1.5k total or $2k+?

 

Hoping to keep the price in that first category.

 

Don't know if anyone ever commented on this but the transmission is right at $2k new.

http://www.gmpartsdirect.com/oe-gm/12577647

I think I am going to switch one of my V8 swaps over to the LFX. Anyone need a V8R LS subframe and road race T-5?

 

If you don't mind the question, where did you source the LFX? Direct from Chevy Performance? Another supplier or private party?

Thanks,

Ray

 

I purchased mine as a complete dropout/engine set from Tri City Auto Salvage in Greensboro, NC.

 

Nice way to go. Got several good breaker yards here in Ohio I can hit.

Ray

 

Final package from V8R arrived!

LFX ECU complete with V8R's tune as well as the interlock deactivated:



Shifter Kit which relocates the shifter to the Miata's position:

 

Hey Ryan, the guys at MER here in Cresson built an LFX RX-8. It's already spun a rod on track. Might be worth picking their brain. Nice folks. Ask for Darin.

 

First post here, hopefully I didnt miss the answer elsewhere, but I have a question about the transmission sourcing. Everyone seems to be quoting that the MV7 version of the AY6 is the way to go with this build because of the gearing, but where did you source the MV7? What I could find through my research was that the only Cadillac to use the MV7 was the 2010-2011 LLT 3.6 and the 2012-2014 with the LFW 3.0. And that the LFX was auto-only in the CTS. Is this all the same transmission/bellhousing across all of these engines? Could we get some clarification as to what trim/engine choices the MV7 can be sourced from? That would certainly make the search for a used tranny much easier.

 

LFX is an evolution of the LLT, they're largely the same block and share the same bellhousing pattern. For sourcing ours we hit up car-part.com, entered 2010 cadillac CTS, and chose MV7 as the option. Car-part will crossreference across the different models for the right option code.

Keep in mind when you contact the yard, they'll probably want the VIN # of the car you're working on to verify fitment (since it's in their best interest to sell you a part that fits). You may have to convince them you know what you're doing.

 

Applications: From the Aisin MV7 wiki:

2004 Holden VZ Commodore
2005 Cadillac CTS
2004 Toyota Tacoma
2006 Holden VE Commodore
2006 Lexus IS220d
2006 Lexus IS250
2006 Toyota FJ Cruiser
2010 Chevrolet Camaro
2010 Lexus IS200d

I would not shy away from the MV5, and it may prove to actually be the superior transmission. The MV7 is newer and has more evenly spaced gears, but if you look at 2/3/4 speeds at expected gearing in the MV5, it looks like you'll be able to hold your gearing more in the MV5...less rowing.

 

From what I could tell looking at the option codes, that application list is quite outdated and applies to the AY6 in general, and not the MV7 specifically. But thanks for the replies. I've been submerged in Mazda engines going back into the 80's so trying to learn the ways of GM and their massive family of parts-bin style manufacturing has been a little overwhelming.

I'm sorry if this is another simple question but I'm not sure if it has been answered, is there a reason that nobody has used the T-56 or TR-6060 with the LFX? Those seem to be really widely available and can hold more torque than the AY6 if you decided to start modding your LFX. A good tune, Mace cams, and well built exhaust can come fairly close to the AY6's quoted 345 lbft max. I'm guessing the bellhousing is different?

 

The T56 weighs like a million pounds.

 

The LFX weighs almost the same as an accessorized 1.8 BP while producing more horsepower than many LS1's. So is an extra 50lbs of tranny in the center of the car that much to lug around if it means you have more headroom for mods? Not to mention that aftermarket support for those trannies is, to put simply, pretty vast. Whereas the AY6 is near non-existant.
What I don't know though is if its even possible to do.

 

Why add more weight than needed?