If the goal is only 300whp a 4.8 Vortec(baby lsx) would fit the bill nicely. You should be able to buy the engine for around $300 and pick up all the supporting stuff for another $300-$500. Put other peoples throw away parts on it (cams designed for the bigger LSx motors, injectors from the same) and you get an honest 300+ whp at high rpms. The transmission (T56) is expensive, but at that power level you might be able to get away with a Camaro t-5?
unevolved wrote: We did some preliminary research on a RWD KL-ZE conversion in a Miata when we were considering various powertrains for our $2010 car. The punchline was that it wouldn't be possible to swap in the motor and boost it on a Challenge budget, and we wanted to go faster than 200hp. It's doable, but there are a few things. (Disclaimer: this is all from memory, from last November) -Coolant flow would have to be reversed. Considering it's conventional FWD layout, the T-stat and radiator inlet/outlet would be at the "back" of the block. Not impossible, but will require some fab. -Oil pan would have to be almost entirely reengineered. -It doesn't bolt up to a Miata trans at first. You need to swap to a Turbo-II bellhousing, and even then a bolt hole doesn't line up. It can be done, yes. That engine would be LOVELY with a small T3. It's fairly high compression, IIRC, so you'd have to be careful with tuning, but I would LOVE to do that. If it was the $3000 Challenge, we might have gone forward with that swap instead, I liked the lower displacement over the VG30E we settled on, but the simplicity of the VG's EMS and propensity for boost were major selling points. On that note, after the Challenge, I'd LOVE to work with someone to replicate our swap in a more "normal" environment without the ultra-tight budget constrictions. There are some things I would have done differently if we'd had a little bit more breathing room. Keith, y'all interested in hiring a new engineer with a business minor in a couple of years?
If you want to save money and throw more boost in that case, skip the KLZE and go with a KLG4 or KLDE. (Millenia 2.5 and Probe/Mx6 2.5 respectively. )
They're stronger, lower compression, and have been proven to make quite a bit over 300whp on stock motors. They can also get INSANELY fast in a hurry. There's a gold MX3 running around with a junkyard Millenia KLG4 in the 11s, and trapping something like 124mph.
Bonus: You still get the OMFGWTFBBQ sound that the KLZE makes, and the heads are actually LESS prone to failure at high RPMs than the KLZE.
Right, I made a proposal centered around the KL-DE for the lower cost, but the points I made still stand. The thing that really turned us off was the engine management, there's just no simple (cheap) solution like there is with early Nissans and Hondas.
unevolved wrote: Right, I made a proposal centered around the KL-DE for the lower cost, but the points I made still stand. The thing that really turned us off was the engine management, there's just no simple (cheap) solution like there is with early Nissans and Hondas.
Engine management? What's that?
Seriously... these guys are hitting DEEP DEEP 12s on FWD crapboxes using those motors with an Ebay kit and an FMU. It's cake. It doesn't get much cheaper than that.
Lots of Megasquirt useage among that crowd too. But in all honesty, i know there's a "right" way and a "wrong" way to do things, but on a KLDE/KLG4, i'd just throw on an FMU and call it a day.
Out of curiousity, what did you guys discover in the way of mounting? I know general rule of thumb is that anywhere you can fit a BP, you can fit a KL or an FE3/F2T, and all possible combinations of such.
A turbo KL miata is on my short list. But also so is an F2T Miata.
In reply to MrJoshua:
Alright....this is the first thing in this thread that has really made my ears perk up. Only problem is a 4.8 Vortec is iron block, right? Does it have iron heads or aluminum? I didn't realize they were going that cheaply. At 300 hp, yeah, I think a T-5 would probably hold up. As would the stock rear end (for a while). I would need to find taller gears for it, but they're around.
I had considered trying to find the aluminum L33 5.3 out of the newer Crew Cab Silverados, but the cheapest I could find one anywhere near here was almost a grand. And then I'd have to spend another grand on a T56, and reengineer the rear end, and probably fab up a new front subframe, (or seriously modify the stock one) and suddenly this starts to get real expensive.
Anyone know what the weight difference between an iron LSx and an aluminum one is? I know that even the iron ones are still pretty compact and light for a V8, but still. Don't wanna saddle the car with any more extra weight than necessary.
93celicaGT2 wrote: Out of curiousity, what did you guys discover in the way of mounting? I know general rule of thumb is that anywhere you can fit a BP, you can fit a KL or an FE3/F2T, and all possible combinations of such.
All we discovered was that it's possible with oil pan work. We never got beyond that.
In reply to psteav:
The truck motors (cheap ones) are iron block with aluminum heads. I think the weight is 70-80lbs more than the aluminum block. You would make up some of that difference using the t5 instead of the t56. Car-part.com is where I found the cheap ones.
We have a miata local to me with the original posters swap. Send me an email/message and I'll give you his email so you can pick his brain. Super nice guy/car addict.
I got two 5.3L truck motors with under 100k miles on them (one 60k and one 85k) as a package deal for $300 from a salvage yard with a 30 day replacement warranty. They had cut harnesses, but enough for Megasquirt. Before that I got a 4.8L with 25k miles on it and everything, harness, ECU, fuel pump and all, for $400, with a 90 day warranty.
The truck LSx engines are so cheap I'd almost rather swap one in than change a valve cover on an old SBC.
In reply to psteav:
bummer i saw this so late. i think its a great idea :) there are a few of us running sr's (me in nor cal, one in OR running NA sr, and there is another black one i lost track of).
its a great little motor and it fits in there reasonably well - and get this, with spec miata cage and very minimal weight reduction (IE: still has full dash/HVAC/wipers/headlights) i'm at 2286 wet. reading through the comments, i see a lot of them are spot on sr vs turbo bp.
the only things i would add would be: sr would give you a factory turbo drivetrain with an aluminum block (weight savings offsets weight added by turbo hardware). my car is 200whp with stock motor/turbo/ecu and as such the drivetrain is completely non-stressed. with a change to a gt28rs (2860) you are now 300whp with the same torque curve, also with relatively unstressed drivetrain. the only problem you will have to work out is getting rid of the heat. there isn't a lot of frontal area on the miata so you have to be careful about airflow management.
that said, i wouldn't attempt to put a sr into a miata unless you were committed to going dry sump (ARE has a sr20 dry sump pan). it lowers the motor down and solves the pan interference problem. this is good because the sr motor is a bit tall.
turbo bp is also nice, and the engine parts are available to do 300whp. you will need to go through the whole engine tho not cheap. what i have seen however is some broken gearboxes this season. so turbo bp is putting stress on the gearbox and i'm not sure if there is currently a good answer for that.
John Brown wrote: Now that we know 300 is the real number then we can dispense with all the minor formalities. * Ford 5.0L * Chevrolet LSx * Chevrolet small block * Lexus V8 * Nissan V8 * Northstar * RB26DETT * 2JZGTE For starters.
You forgot the 7.3 Powerstroke and the Detroit Diesel 6V92.
unevolved wrote: We did some preliminary research on a RWD KL-ZE conversion in a Miata (stuff and oher stuff) -It doesn't bolt up to a Miata trans at first. You need to swap to a Turbo-II bellhousing, and even then a bolt hole doesn't line up.
...wait, what?
The KL bolt pattern is only one off from a rotary?
Very, VERY interesting.
psteav wrote: Anyone know what the weight difference between an iron LSx and an aluminum one is? I know that even the iron ones are still pretty compact and light for a V8, but still. Don't wanna saddle the car with any more extra weight than necessary.
All LSX blocks are iron.
I only ever saw one LSX, and it was still in the shipping crate. I did play with an iron 6.0 once (production aluminum blocks are... power limited) and the bare block felt about as heavy as that of a 440 Chrysler. There is a LOT of metal in that casting.
There are aluminum 5.3s available in some trucks. The 5.3 and the 4.8 are rated almost the same in power, the 4.8 just has slightly less torque.
Knurled wrote: All LSX blocks are iron.
LSx != LSX. Case is important here, as all N/A LSx motors are aluminum block
But LSn =/ Gen III/IV Chevy. If you're getting a truck engine, it is not an LS designation. (And if you're getting an iron block, it wasn't from a car)
Rather get a truck engine anyway. Cars are more likely to have been abused, I'd think.
tonto wrote: turbo bp is also nice, and the engine parts are available to do 300whp. you will need to go through the whole engine tho not cheap. what i have seen however is some broken gearboxes this season. so turbo bp is putting stress on the gearbox and i'm not sure if there is currently a good answer for that.
For the record, there are quite a few stock motor BPs putting out 300whp+. Definitely doesn't address the transmission issue, though.
93celicaGT2 wrote: For the record, there are quite a few stock motor BPs putting out 300whp+. Definitely doesn't address the transmission issue, though.
on the track? are you sure? FM site says 12psi for stock internals, and i've never met anybody close to 300 who was on their first engine.
maybe your right, but that means me and everybody i know who is chasing the elusive reliable turbo miata is doing something wrong :)
in my mind, that is where the sr becomes interesting. strong engine, phenomenal aftermarket support, and well understood weaknesses. IE: i bought a used gearbox with os giken gearset (gives me 50mph in 1st, 75mph in 2nd, and 105mph in 3rd, and handles 600whp) for $1k. stock gearbox is fine, but if aftermarket close ratio gearsets are available at that price, imho this becomes a phenomenal track platform.
4BT!!!
tonto wrote:93celicaGT2 wrote: For the record, there are quite a few stock motor BPs putting out 300whp+. Definitely doesn't address the transmission issue, though.on the track? are you sure? FM site says 12psi for stock internals, and i've never met anybody close to 300 who was on their first engine. maybe your right, but that means me and everybody i know who is chasing the elusive reliable turbo miata is doing something wrong :) in my mind, that is where the sr becomes interesting. strong engine, phenomenal aftermarket support, and well understood weaknesses. IE: i bought a used gearbox with os giken gearset (gives me 50mph in 1st, 75mph in 2nd, and 105mph in 3rd, and handles 600whp) for $1k. stock gearbox is fine, but if aftermarket close ratio gearsets are available at that price, imho this becomes a phenomenal track platform.
Check out the Escort, Protege, and 323 forums.
Now, keep in mind that these guys aren't doing endurance lapping or anything, and i'm not sure if i'd personally trust a 300whp stock motor BP on a LONG track day either, but just sayin'.
The one big point in my mind FOR the SR20DET is the transmission. In most cases up to a point, it's cheaper to just use what you have. The BP is a capable motor, and for the price it would cost to buy the SR20 and swap it in, i'm reasonably sure that someone handy could at least equal the power in a reliable fashion with the BP. But in the end, you've still got a semi-sketchy gearbox.
I'm not really for or against either motor. If i were doing it, i'd go BP, just because i know them better, and i hate doing motor swaps. But those are fairly personal reasons, and i don't expect to "convert" everyone to my thinking. 
93celicaGT2 wrote: maybe your right, but that means me and everybody i know who is chasing the elusive reliable turbo miata is doing something wrong :)Now, keep in mind that these guys aren't doing endurance lapping or anything, and i'm not sure if i'd personally trust a 300whp stock motor BP on a LONG track day either, but just sayin'.
Exactly. There's a local guy who has a friend with a Honda D16 that "makes 400hp all day long". No, it makes 400hp for the last 500 feet of a 1/4mi track, and then cools off for 20-30 minutes. Put it in steady state 400hp mode and you're going to find all sorts of deficiencies.
The one big point in my mind FOR the SR20DET is the transmission. In most cases up to a point, it's cheaper to just use what you have. The BP is a capable motor, and for the price it would cost to buy the SR20 and swap it in, i'm reasonably sure that someone handy could at least equal the power in a reliable fashion with the BP. But in the end, you've still got a semi-sketchy gearbox.
Ayup. In the end, a sweet engine means nothing if you can break 2nd gear by just rolling into the throttle.
There are very few 300 hp BP cars doing regular track duty, and even fewer doing it without problems. How many of those are on stock internals? Very few. But all it takes is two guys posting to the internet that it can be done, and suddenly you have "quite a few" There certainly are more than there were a few years ago. But there are also more engine failures than there were a few years ago.
unevolved wrote:93celicaGT2 wrote: Out of curiousity, what did you guys discover in the way of mounting? I know general rule of thumb is that anywhere you can fit a BP, you can fit a KL or an FE3/F2T, and all possible combinations of such.All we discovered was that it's possible with oil pan work. We never got beyond that.
Did you ever consider the 3.0L from a Mazda 929?
It had all the big issues (pan, cooling) resolved.
93celicaGT2 wrote: The one big point in my mind FOR the SR20DET is the transmission. In most cases up to a point, it's cheaper to just use what you have. The BP is a capable motor, and for the price it would cost to buy the SR20 and swap it in, i'm reasonably sure that someone handy could at least equal the power in a reliable fashion with the BP. But in the end, you've still got a semi-sketchy gearbox.
ah, yes you can build the bp no problem, but if i blow up my sr20, all i gotta do to fix is go down to the importer, find one with a working oil pump 
and i'm good to go. is that enough to offset the pain of the motor swap? not sure.
A blown up BP is cheaper to replace than a blown up SR20DET. Granted it will likely blow up 50whp sooner than the SR20DET!
There's a guy selling a 96 Miata engine locally for $100 (ran fine when replaced with a 99) today on CL. I thought about getting it just to have a spare, but I just don't have the room.
John Brown wrote:unevolved wrote:Did you ever consider the 3.0L from a Mazda 929? It had all the big issues (pan, cooling) resolved.93celicaGT2 wrote: Out of curiousity, what did you guys discover in the way of mounting? I know general rule of thumb is that anywhere you can fit a BP, you can fit a KL or an FE3/F2T, and all possible combinations of such.All we discovered was that it's possible with oil pan work. We never got beyond that.
No, but that does look interesting. I'll remember that for the future.
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