A miata pictorial tale of Irony

In reply to Patientzero :

I thought of your car as the guy went into why he thought mustangs should never have LS ;)

I just smile and nod for folks like that, not much point in debating with purist.

In reply to codrus (Forum Supporter) :

Funny, for me that was one of the easiest part of the swap. It took a short evening and I accidentally over-clearanced my tunnel, lol. I drank one too many white claws and went at it with the sledge.

Drilling holes in oil pans bothers me a lot more. But do keep in mind, my context and mindset is for a race car or track focused build. I'm certainly not going to argue that LS was easy, cheap, or that it's for everyone - but it makes a lot of sense in many contexts.

accordionfolder said:

(hell, even 300+ is very dangerous all mazda)

A 6-speed will stand up to 350 rwhp for a decent amount of time, so long as you're not trying to do drag-race style launches on it.  I killed a 5-speed at 260 rwhp (stripped all the teeth off 3rd gear), but the only 6-speed I broke was an input bearing failure.  It's likely that that transmission would still be working if I'd put a proper cooler on it.

I never broke an axle or a differential -- I broke everything ELSE in the car, but the drivetrain was actually pretty solid. :)

In reply to codrus (Forum Supporter) :

Spec Miata and endurance Miata kill both the 5 and 6 speed regularly at stock power levels. My race miata FB group is always trying to find ways to keep them alive longer. Gotta keep in mind context. Mazdaspeed has a gear set that I haven't read results on yet, but when you're racing it's just a question of when. 

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accordionfolder said:

In reply to codrus (Forum Supporter) :

Spec Miata and endurance Miata kill both the 5 and 6 speed regularly at stock power levels. My race miata FB group is always trying to find ways to keep them alive longer. Gotta keep in mind context. Mazdaspeed has a gear set that I haven't read results on yet, but when you're racing it's just a question of when. 

FWIW, my experiences were with a car that saw monthly-if-not-more-often track days.  Yes, racing is harder on parts than track days are, but this isn't street car use.

In reply to codrus (Forum Supporter) :

Hahah, we're certainly far afield now!

I'm not here to doubt or discount your experience. My point is more, if you know of someone keeping even a six speed alive for the cost of a new t56 season over season and racing at 300whp, that'd be news to me! I'm putting down around 400whp and my transmission doesn't even notice it. I've run through the calculations and gone over and talked with a ton of builders and racers before I decided it was going to be LS or LFX due to cost and reliability season over season. I ended up finding a trans and swap parts for roughly half off so it's where I went!

When i was at Gridlife CMP, there was a low power K swap Miata GLTC car that grenaded a (**edit, it was only one) six speed and he didn't race period that weekend. Marcus L.'s car (I think only 185whp?) - and thats just sprint racing.

codrus (Forum Supporter) said:

Keith Tanner said:

The big advantage to a full drivetrain swap (engine, trans, rear) is that they're seriously overbuilt and were engineered by the factory with a pretty big budget. The end result is better IMO but it's a much bigger leap to get there.

The most daunting part is the one where you strip out everything from the engine bay and interior, scrape off a bunch of the undercoating, and modify the transmission tunnel with plasma cutter and welder. :)  I've seen the photos!

Sure in principle it's not that big a deal, but you can build a 350 rwhp turbo car with just wrenches -- no welding required and only a very small amount of cutting to clearance the shelf.  That's appealing to a lot of people.

 

Definitely. The first in-progress Miata LS swap pictures I saw - before the kits were available - were pretty terrifying.

Although drilling a hole in the oil pan for a turbo drain makes a lot of people pretty nervous despite the very low failure rate.

In reply to Keith Tanner :

Lol, you can say that one is no big deal all you want, metal shards, big hole into the oil pan makes me nervous! ;) 

accordionfolder said:

In reply to calteg :

Seems to breathe ok, probably could make more power with dual or single 3", but 2 to 1 2.5" fits easy and power isn't a problem yet.

I have made 750 through a single 3", you be fine.

codrus (Forum Supporter) said:

accordionfolder said:

(hell, even 300+ is very dangerous all mazda)

A 6-speed will stand up to 350 rwhp for a decent amount of time, so long as you're not trying to do drag-race style launches on it.  I killed a 5-speed at 260 rwhp (stripped all the teeth off 3rd gear), but the only 6-speed I broke was an input bearing failure.  It's likely that that transmission would still be working if I'd put a proper cooler on it.

I never broke an axle or a differential -- I broke everything ELSE in the car, but the drivetrain was actually pretty solid. :)

 

Either I am an animal or Miata horses are a lot smaller than rotary horses.  I have broken more transmissions (same 5sp) than I care to count as well as axles and diffs (same size parts), including fatally damaging an ex-NASCAR locker diff in a 9" Ford, after I ran out of Mazda parts to break.  Never made over 210whp, all RPM no forced induction.

My favorite was the time I shifted to 5th gear at 85mph and ripped all the teeth off of the input shaft.  Made the rest of the drive to work in 4th because that is all that was left.  Fortunately, work was only three traffic lights away from the Interstate and two of them were green.

In reply to Pete. (l33t FS) :

My understanding is RPM is a large part of the equation, especially when things start getting hot, but I can't claim to be an expert or even know what rpm the rotors be spinning! 

Pete. (l33t FS) said:

Either I am an animal or Miata horses are a lot smaller than rotary horses.  I have broken more transmissions (same 5sp) than I care to count as well as axles and diffs (same size parts), including fatally damaging an ex-NASCAR locker diff in a 9" Ford, after I ran out of Mazda parts to break.  Never made over 210whp, all RPM no forced induction

Eat drums!  Eat drums!

My understanding is that Miata transmissions and RX7 transmissions don't actually have much in common.  The 6-speed especially is an Aisin, just in a Mazda-compatible case.

I have no idea how you break a Ford 9" with that little power, unless you are deliberately engaging in wheel hop?

In reply to codrus (Forum Supporter) :

The RX-7 smoothcase and Miata five speed are the same transmission.  Like, you can strip off the front and rear trans housings and slap RX-7 housings on and bolt it in, or vice versa, aside from an input shaft length difference.  (edit: treatise here to unclutter thread )

I didn't really "break" it per se, but it ripped up the drive dogs enough that the drive plates were disengaging under power, which is kind of the opposite of why I wanted a locker.  Made for some consternation until someone pointed out that when I lifted an inside rear under power, the outside would stop spinning.  Swapped in a $200 Trac-Lok from a certain circle track shop in Iowa and all was well.  Which is the REAL benefit of a drivetrain upgrade:  Once you have a 9" or 8.8" in there, you have access to a wide variety of gear ratios and every type of differential ever made, usually fairly inexpensively.  No $1200 plus overnight shipping from Japan.

Hmmm. Zero discussion of weight difference between swaps so far. My turbo car weighed in at 2400 lbs all up at prosolo nats with me, my helmet and a handheld extinguisher. It has a full dash and mostly complete interior, heater, hardtop, headlights and is completely street legal.

Is it even possible to get an LS swap down to those numbers?

I think mechanical empathy is everything when it comes to the drivetrain. I used to run a five speed and it's still fine. Survived years of hillclimbs and autocross at 200+ hp. Sure, the shift lever will be basically in your lap as the housing twists. Yes, you have to slowly add power and let everything wind up. But it's possible. The only failures I've had are bent rods. So many bent rods.

In reply to dr_strangeland :

My car is at 2475 w/ me in it(185lbs so 2290 no driver), full tank. Bronoson's LS3 NB car which has **edit MORE interior than mine, but it's also fully caged - is a bit heavier at 2350 w/o driver. Turbos and aluminum LS miata are pretty much the same weight window. That's actually the least relevant of the arguments for or against LS, though people love to bring it up.

Mine is on the heavy side because of cage, full fire system AND emergency extinguisher, 50lb battery in it right now, full length-steel subframe braces that I don't need because I'm caged, and t56 magnum vs TKX trans (75lbs lighter). Weight isn't a major concern for me because I'm going to have to detune regardless for GLTC - I may add weight if anything to go bigger on the tires.

I drive my cars like I hate them. 

In reply to dr_strangeland :

Though - as I mentioned in a few other random places - I'm not implying that an LS miata would be a perfect tool for the job you're doing either. I love all miata: turbo, super, LS, LFX, dual duty cars, street or race cars. I think it's a perfect platform.

For my particular set of working parameters and budget the LS miata makes the most sense. Keep in mind I also have a VVT track rat NA, and two spec miatas as well. So I've got my bases covered. I drove the spec miata more than the LS this past weekend! 

IIRC, the BP + turbo hardware weighs about the same as the LS, but the T-56 and GM diff weigh more than the Mazda versions.  So as with the cost question, it's going to depend on how much power you want to make and how much you're willing to put through the Mazda bits.

dr_strangeland said:

I think mechanical empathy is everything when it comes to the drivetrain. I used to run a five speed and it's still fine. Survived years of hillclimbs and autocross at 200+ hp. Sure, the shift lever will be basically in your lap as the housing twists. Yes, you have to slowly add power and let everything wind up. But it's possible. The only failures I've had are bent rods. So many bent rods.

Time for some Carrillos?

dr_strangeland said:

Hmmm. Zero discussion of weight difference between swaps so far. My turbo car weighed in at 2400 lbs all up at prosolo nats with me, my helmet and a handheld extinguisher. It has a full dash and mostly complete interior, heater, hardtop, headlights and is completely street legal.

Is it even possible to get an LS swap down to those numbers?

LS swap adds approximately 200 lbs to a stock NA/NB Miata, about 1/3 of which lands on the rear wheels. Sure, it's a bit heavier but it's got roughly 4x the power and all the torque so you don't really notice.

My car is about 2320 lbs without me in it, in street legal form with a hardtop. It doesn't have a complete interior but it does have a roll bar and some extra mass in the brakes as well as an extinguisher and a full tank of fuel (60 lbs). It's built to be a complete anvil at track days. I drive my cars like I'm the one who has to fix them (big fan of mechanical empathy) but it's nice not to have to even think about the drivetrain.

You can't just look at peak power numbers, either - it's delivered in a very different way. They're quite different to drive than turbo cars.

codrus (Forum Supporter) said:

IIRC, the BP + turbo hardware weighs about the same as the LS, but the T-56 and GM diff weigh more than the Mazda versions.  So as with the cost question, it's going to depend on how much power you want to make and how much you're willing to put through the Mazda bits.

 

Yeah, agreed. 

Another option I'm hearing about is the TKX - It still weighs more than the mazda trans (70-something lbs), but the TKX is 99lbs vs 140lbs for the t56 magnum I have - I think it's happier at higher RPM too - though I'm keeping my rev-limiter at 6500 so it's not a big problem. Especially in a race only context the 5 speed probably makes more sense - I'll never use 6th gear. 

In reply to Keith Tanner :

With what little track testing and I keep shifting like a miata when I should be leaving it up a gear. It's fun, but not fast.

WHEEEEEEL SPINNNNNNN, GRIP gooooooooo BRAKE.BRAKE.BRAKE. 

My brain riding the wave.

Does the TKX shift better than the T56?

In reply to buzzboy :

According to everything I've read, it's much better - but I have no personal experience with it.

The T56 Magnum shifts better at high rpm than the normal T56 (I've had both in my Miata), but in both cases they seem to like fast shifts better than grandma ones. When you're motoring, it's fast and smooth. 

accordionfolder said:

In reply to Keith Tanner :

With what little track testing and I keep shifting like a miata when I should be leaving it up a gear. It's fun, but not fast.

WHEEEEEEL SPINNNNNNN, GRIP gooooooooo BRAKE.BRAKE.BRAKE. 

My brain riding the wave.

I had a weird tuning problem once that put me into a limp mode on some hard shifts (an airflow limit that didn't show up at altitude). So I ended up doing an entire session at Laguna Seca with the car in 4th. It was rpm limited on the climb to 7 and the straight, but otherwise it didn't seem to mind :)

For corner exit, squeeze the throttle instead of slapping it open. It's amazing how well it'll put down power if you don't shock the tires loose.