K-Miata vs V6 Miata vs LS Miata vs Rotary Miata

In reply to KyAllroad (Jeremy) :

The problem is that T56s have gotten mighty expensive. A friend of mine had a salvage yard Trailblazer SS LS6 and a full LS swap kit for his S13. Only thing he needed was a T56. But all of them were gone from junkyards and every one he found for sale people wanted an arm and leg for, and half of those had bad synchros or needed a rebuild. In the end, he sold the LS6 and the swap kit, then took that money to go grab a cheap high-mileage LS400 as a 1UZ donor, a W58(?) Toyota manual trans and a 1UZ swap kit and had money left over.

The 1uz isn't as compact as the LS but it's not much bigger.  I've not been around any of these swap; the internet makes it seem like about the same amount of work to get the 302, an LS, or a 1uz into the engine bay of an MX-5.  I wonder which of these swaps would be the easiest to pass smog with in New England...

Thinking about fun projects and a V8 Miata seems right up there.  I have other, seemingly smaller projects in front of this, though.  

My buddy has a 1uz/w58 swapped Cressida and 1st gear is completely useless. It's basically a crawler gear, even with having swapped the rear 4.10 for a 3.73.

Some of the LS's weight advantage also goes away with a T56 behind it.  

I think the LFX swap uses the Aisin trans from the donor camaro v6, also it has exhaust manifolds built into the head which makes the exhaust routing way easier. Also I believe its the same motor just boosted in the ATS-V and the like?

NickD said:

In reply to yupididit :

J-series seem to be much more common and, as a result, cheaper. The LFX is a relative newcomer. Meanwhile, Honda has been cranking out J-series in a number of vehicles for a over a decade. The J-swap also reuses more stock components, keeping the kit cheaper. The LFX is also a real pain to work on, although I have no experience working on Js

What about it makes it a pain to work on? Asking because I'm seriously considering swapping one into my conquest. 

Regarding the Ecotec swap: I believe I've read the turbo applicable external bits from the 2.0L LNF engine will fit on the n/a 2.4L LE5. To me that seems like the easiest way to go if you want semi-practical big power.

Snrub said:

Regarding the Ecotec swap: I believe I've read the turbo applicable external bits from the 2.0L LNF engine will fit on the n/a 2.4L LE5. To me that seems like the easiest way to go if you want semi-practical big power.

Ecotec miata mentioned this to me as well, but when I contacted ZZPerformance who are pretty much the ecotec performance aftermarket experts they said the LE5 internals cannot handle the power the LNF can and by the time you start adding FI bits to the LE5 you would be better off starting with the LNF.

That being said I was seeing LE5's for around 900, and LNFs were about 2k sans turbo, however ZZPerformance sells brand new stock turbo/oil line/etc packages for like 900, so for about 1k extra dollars you get an engine that can have factory levels of reliabilty at 300whp vs 200whp with the LE5, taking the LE5 to 300 with FI will potentially create more issues.

Look, It's all about how much you want and how much you want to spend. Anything with the stock miata transmission is only good for so much HP before it goes. Same with the stock rear diff. Not a big fan of the trouble needed to do any of them honestly. 

Is a LS3 Miata a blast to live with daily....Heck yeah. But there is a price to pay for that. Not only in $$$ but the transmission feel is a lot different than a stock miata transmission. It needs the most because you get the most in return. 

To me all of the 4 cylinder swaps are about the same. It's just a matter of do you prefer a GM or Honda motor. There is a bit of a difference in area under the curve.

I like the V6 swap. To me it's a Goldilocks swap. Doesn't add a bunch of weight and still can get the power down. 

Considering what i've seen with my own eyes and personally driven, any swap away from the BP for mild hp goals is really only justifiable on subjective measures. If you're just trying to go fast... if you can't do it with a boosted bp you likely also cant personally pull off the swap you think will fix it. All engines are basically the same as far as figuring out how to make power. The only thing that varies greatly is the accuracy of the 'conventional wisdom' that is regurgitated in each community mostly by people who are fairly low level as far as their knowledge and mechanical competency and are parroting the statements of people they assume to be right although they have no context to judge the issue. The miata community seems to be pretty fatalistic about the reliability of stock components, which i think is why everyone is interested in swaps to engines that the internet lore is less depressing about. I think some of that is because a lot of Miatas having serious track time endurance testing various setups for long periods of time, but if racetrack wisdom about what parts will die prevents someone from building something fun that would have lived on the street, it's counterproductive. Unless you're trying to sell swap kits, i guess.

I think the only Miata swap i'd personally consider seriously is mixing and matching duratec stuff in an NC. 

Ah in an NC chassis you mean Vigo? because the duratec in the NA/NB is the swap I have seen the least (in fact never), a 200hp miata is plenty fast and you don't really start breaking things until upwards of 230, but who is ever satisfied :P

Jaynen said:

Snrub said:

Regarding the Ecotec swap: I believe I've read the turbo applicable external bits from the 2.0L LNF engine will fit on the n/a 2.4L LE5. To me that seems like the easiest way to go if you want semi-practical big power.

Ecotec miata mentioned this to me as well, but when I contacted ZZPerformance who are pretty much the ecotec performance aftermarket experts they said the LE5 internals cannot handle the power the LNF can and by the time you start adding FI bits to the LE5 you would be better off starting with the LNF.

That being said I was seeing LE5's for around 900, and LNFs were about 2k sans turbo, however ZZPerformance sells brand new stock turbo/oil line/etc packages for like 900, so for about 1k extra dollars you get an engine that can have factory levels of reliabilty at 300whp vs 200whp with the LE5, taking the LE5 to 300 with FI will potentially create more issues.

An early LE5, if I remember correctly 06-07, has forged internals and can be trusted to 300whp. The later years can’t. 

I won't tell you where I saw this, BUT the RX8 diff fits in the NC Miata and holds 300+ hp easily so that makes the NC, even tho it's the ugliest Miata ever made, a good choice.

simplecat said:

My buddy has a 1uz/w58 swapped Cressida and 1st gear is completely useless. It's basically a crawler gear, even with having swapped the rear 4.10 for a 3.73.

I have a 1uz/w58/3.73 gears. It’s not bad. It’s not track useable, but it isn’t any worse than first gear in any civic. My car tops out at 140mph. Besides, 1st gear is normally useless on any track. And 2nd is fine for autox since the motor has such great low end torque. 

yupididit said:

NickD said:

In reply to yupididit :

J-series seem to be much more common and, as a result, cheaper. The LFX is a relative newcomer. Meanwhile, Honda has been cranking out J-series in a number of vehicles for a over a decade. The J-swap also reuses more stock components, keeping the kit cheaper. The LFX is also a real pain to work on, although I have no experience working on Js

What about it makes it a pain to work on? Asking because I'm seriously considering swapping one into my conquest. 

The timing system on them is a nightmare. It has a primary chain, and two secondary chains. You have to install a locking plate and set up the Bank 1 secondary timing chain, then set up the primary chain, then rotate the entire engine 20 degrees,  install the locking plate on Bank 2 then setup the Bank 2 secondary chain. If it's off a tooth, it sets a check engine light. But the locking plates will still slide on to the cams if it's off a tooth. Get more than a tooth off and you're looking at replacing valves. We get tons of them into our dealership that people have attempted to replace the timing chains themselves, or had an independent shop do them, and have screwed it all up.

The High-Feature V6 has been a troubled engine since it's introduction. Porous heads that leak coolant, valves that build up carbon and stick, timing chains and tensioners and cam actuators that fail reliably at 100K (sometimes earlier), oil consumption, injector failures.

I have never rotated the engine 20 degrees for the right side, or used locking plates when replacing timing chains on a High Feature.  They only want you to rotate the engine for the right side to put the camshafts in a neutral position, because they assume you are a moron and don't know how to juggle two wrenches in the same hand to hold the cams in position while you put the chain on.  (Chain FIRST, then move around to install the guide... you can also install the adjuster first and slide the shoe in after, makes life easier)  OTOH most people at GM dealerships never had to work with Toyota or Subaru or especially Mitsubishi 4-cam timing belts so they probably never had a chance to learn the skills.

Then again, i also don't understand why anybody has issues with them.  They're freakin' simple, just line up the dots.  The cams and crank are keywayed, unlike most modern engines which are unkeyed, so this is all you can do.  The jackshaft sprockets turn asynchronously from the crank and the cams (allows the crank sprocket to be larger for chain life, and the cam sprockets to be smaller for reduced space) so you can't follow them other than just lining up the dots.  They were even kind enough to make the primary chain trilaterally symmetrical, and the secondary chains bilaterally symmetrical.

Here's the one I have at work right now.  Ever see this happen?

The right side chain was 6 teeth off on both the intake and exhaust.  Engine had no oil in it.  Found that the exhaust sprocket bolt was loose when I was rolling the cam into place when installing the right side secondary chain.

All six exhaust valves were bent, but only one or two in cylinder 3 were bent enough to not hold compression.

BTW - Engine at 150k, tensioners still had a lot of extension left, and it looks like nobody had ever been in there yet.  Problem looks entirely due to training the engine to run four quarts low on oil.  No idea where the oil went because the outside of the engine was as dry as a desert skeleton and the ports and chambers were almost completely clean of carbon.

I've seen an Ecotec Miata do impressive things on a track, so while it certainly doesn't have thirty years of track experience from thousands of different people, it's not one of these setups that can only survive street use driven to cruise events on weekends. There are a lot of people running turbo BP setups, but you also hear about issues. It's not clear to me how reliably and consistently a turbo BP can do dozens of hours on a track (?).

While the NC 2.5L swap is interesting, it also has it's detractors like Keith. That's probably the point of this thread - there are different answers for different people.

Snrub said:That's probably the point of this thread - there are different answers for different people.

So, you're saying that the people who want knife-edge handling are different from the people who think it's a piece of E36 M3 if it can't do a rolling burnout in 5th gear?  That's crazy talk!

(I WORK with one of thiese people.  We had a Boxster in for some maintenance and repair, and he kept going on about what a piece of E36 M3 it was.)

For track only use(like my na miata)dealing with the heat generated by a boosted BP(like my miata)is tiresome.

 An ecotec makes economic sense for my budget,but I'd love a K swap if I had the $$$.

 I have a W58 trans in the shed,the 1uz keeps calling but I think I will resist....unless I found a cheap adapter setup.

NickD said:

yupididit said:

NickD said:

In reply to yupididit :

J-series seem to be much more common and, as a result, cheaper. The LFX is a relative newcomer. Meanwhile, Honda has been cranking out J-series in a number of vehicles for a over a decade. The J-swap also reuses more stock components, keeping the kit cheaper. The LFX is also a real pain to work on, although I have no experience working on Js

What about it makes it a pain to work on? Asking because I'm seriously considering swapping one into my conquest. 

The timing system on them is a nightmare. It has a primary chain, and two secondary chains. You have to install a locking plate and set up the Bank 1 secondary timing chain, then set up the primary chain, then rotate the entire engine 20 degrees,  install the locking plate on Bank 2 then setup the Bank 2 secondary chain. If it's off a tooth, it sets a check engine light. But the locking plates will still slide on to the cams if it's off a tooth. Get more than a tooth off and you're looking at replacing valves. We get tons of them into our dealership that people have attempted to replace the timing chains themselves, or had an independent shop do them, and have screwed it all up.

The High-Feature V6 has been a troubled engine since it's introduction. Porous heads that leak coolant, valves that build up carbon and stick, timing chains and tensioners and cam actuators that fail reliably at 100K (sometimes earlier), oil consumption, injector failures.

 

 So these kajillion v6 camaro, Cadillacs, and other Chevy cars are having these issues? I never heard of this until now. 

In reply to kevlarcorolla :

 Look for cheap used adapters on sites like zilvia.

With all this V6 talk, what's the consensus on the Toyota 2GR-FE and Ford/Mazda Ecoboost/Cyclone engines? I know that the 2GR has that awesome ~300 lb/ft of torque, but Toyota ECUs just LOVE to immobilize themselves and the Ford Cyclone V6es are DCI.

I really enjoy engine swap discussions, but can't take one on myself. A little beyond my skills, especially for the electronics and way beyond my time availability. 

Fun to fantasize about, but even those with the skills and knowledge get stuck. Remember the miatabusa on MotoIQ? I don't think that ever was finished. 

How about a Gold Wing flat six? Didn't some of those have a reverse gear to allow the rider to idle it backwards?

In reply to yupididit :

I have no idea what zilva is and google failed me.....able to spoon feed me some additional info?

In reply to kevlarcorolla :

zilvia.net