Midtenn

iTrader: (15)

Quinn on ClubRoadster did a "budget" build on a 99-00 motor and reached your power goals and it didn't really require anything exotic. My 172whp N/A Engine. Stock bottom end. No Porting. There are few parts in there you could substitute out for some more inexpensive items (like a Racing Beat header instead of a Mahura, and square top manifold w/ skunk2 throttle body for the TWM ITBS.) and still get similar results.

turbofan

iTrader: (1)

Props for obviously doing a lot of research.

If you're about reliable HP and want 170-180 whp, A mechanically-sound '94-95 with a rotrex will get you there. Reliable. I am super impressed with how Mobius' '01 has held up with his rotrex.

You'll get it figured out though. I know a thing or two about indecision

aidandj

iTrader: (5)

Rotrex make sissy torque the stock block handles it just fine. Rotrex on stock motor with better cooling would be a cool hpde car. It's exactly what Mobius ran until this recent winter rebuild. 174hp I think, he can chime in with real numbers.

Voltwings

What i find nuts though is the fact that the all motor cars arent really that far behind the boosted ones? Maybe 20-30 whp? Maybe i am just jaded from my time in the mustangs, but i feel like if its "that" close, i really would like the all motor option for lack of heat and less weight off the nose.

Granted, enough people are saying rotrex to at least make me partially consider it. Back when i was tuning mazdaspeed3s we actually set the stock turbo record with a healthy dose of pre-turbo methanol through the stock turbo (about 1 gph @ 80/20 meth to water). We did 5000 miles of testing and it seemed to be holding up ok ... i'm wondering if the rotrex materials would be able to handle pre turbo meth.
Mind you, its such a small amount, and such a fine atomization, and most of it evaporates instantly, that very very little actually ends up making contact with the wheels. I can post the thread here if thats cool? I know some forums are strict about not linking to other forums.

aidandj

iTrader: (5)

I mean whats your definition of right behind. The 170hp N/A motors aren't cheap at all, and 200 from a rotrex is reasonably simple. Its been stated before but run NA until you want more power then add rotrex or turbo. Any mod you do to make more power N/A will help boosted power.

Running meth won't effect the fact that Miata stock rods like to exit the block violently when run with a lit of torque under race conditions.

deezums

iTrader: (3)

I think the reason they are "only" 20-30 more is because other things start breaking much higher than 250hp, and you are back to being expensive again. The track is not easy on stuff, it must be better than 100%, whereas a 250HP miata street car can and will do fine on 30%, maybe for a long time.

I'd bet a person could have a 200HP boosted 1.6, or a 170hp VVT beast for about the same dollars. I'd probably take the NA VVT if I were going to a track. I can't afford **** as it is, I'd be super duper pissed to go spend on track days, then start fragging 6 speeds or axles on track.

aidandj

iTrader: (5)

I'd say 170hp VVT would be a lot more. CNC head, square top, header, etc. A 200hp 1.6 cost me less than a CNC head alone costs.

Oregonmon just did a VVT swap and before the squaretop he was at like 135hp. No CNC head.

Chilicharger665

iTrader: (2)

The genius of building it NA first is that then the rotrex kit bolts on and you gain as much HP as you want to add, without changing anything else.

shuiend

iTrader: (24)

Honestly now that the stud stretching issue has been solved, you can make 200-225hp turbo track miatas pretty reliable. Sixshooter and a few others have been running reliably for years. Going above that is where it start to get really expensive. No AC makes it easier. Cooling mods are the same NA or turbo, reroute, half sized radiator, full ducting, hood vents. Ecu costs are the same, suspension costs are the same. Brakes and tires may go a little faster. Might have to switch to a 6 speed, but trans and rear may end needing to be changed with either NA or turbo based on track and what gearing you want/need.

You can also change how much power you make reasonably quickly. You can start at waste gate 170whp or so depending on turbo and move up as needed. With an EBC and TS you can go from 7psi to 12psi in 5 seconds.

aidandj

iTrader: (5)

With an ms3 you can go from 5 to 16 in the flip of a switch.

aidandj

iTrader: (5)

I see what you did there.

ThePass

iTrader: (3)

From a guy who spent ~3 seasons working out the kinks and weaknesses of a turbo before finally having a car that could run full days without sprouting issues, I'd caution against looking to a turbo to reach your goals if you value simplicity and staying within a budget.

I look at the motor as a consumable, which gets real hard to do when you put thousands into it. I prefer the junkyard motor + boost approach, but if I were doing it again I'd go junkyard 1.8, put a Rotrex on it and call it a day. 200+ whp and replace motor every ~2 years. Easy as pie.

That's not to say a turbo miata isn't going to be a blast at the track, but there's really only one way to do it if you want it to kick *** and last, and that way doesn't leave many stones unturned or much money left in one's wallet.

If you want <160 whp, go N/A. Basic SPM builds (99+ junkyard motors with all the bolt-ons) on a high-power tune do 155 without anything particularly fancy.

-Ryan

joyrider

iTrader: (8)

^^^^^Your more patient then me, after 2 years of bad tracktime and lots of headache, I sold everything turbo related. Doing it again with my knowledge now, I would do a *Hustler* turbo build (artech everything for track duty) but it ain't cheap. and guess what, he did finally had trouble and sold everything too...

I'm happy with less power, less weight no more heat and less problem... SPM build are really great and can go all day long without opening the hood once. Great move, thx god for enlighten me

turbofan

iTrader: (1)

^fwiw it wasn't artech, it was absurdflow. But aside from that you're right.

Also echo that 200 whp turbo is a helluva lot cheaper than 170whp NA if you're talking pump gas.

shuiend

iTrader: (24)

Yeah I was hoping someone would catch it.

joyrider

iTrader: (8)

2Am not enough beer I guess, you're right ! sorry...

aidandj

iTrader: (5)

Hustler did have artech stuff. All v-band. Savington used inconel and it worked too.

turbofan

iTrader: (1)

Nnnnoooooope. His was an absurdflow car. Unless he built one with an artech setup after that.

Not really relevabt to the conversation though I guess.

aidandj

iTrader: (5)

Damn your right. **** gets confusing, I just checked old fs threads.

Voltwings

Ok, i think i realize where a lot of my confusion is coming from, and its even evident in this thread: junkyard motor with bolts ons = 135, bolt ons with VVT = 140-150 yada yada yada

I was up until 2am last night just because i couldn't sleep, so i was researching Na (as in all motor) builds and Bolt on mods. I read about the VICS manifold, the VTCS with and without butterflys, read about the flat top manifold. There seems to be fan boys for every approach, and lots of "word of mouth," and "hearsay" but very few actual dynos and results, and even fewer are really done in a controlled scientific manner. I cant blame people for that, its a lot of time and money to privateer something like this so... it is what it is.

That being said though, it does create a lot of confusion, and i think i realize a fatal flaw in my goals as well. I'm aware of how runner length and plenum size affect power bands after changing from a long runner maniold to a short runner on my 5.0: Lost ~20 ft/lbs of torque but gained about 40 whp lol ... luckily my 380 wtq car could afford to lose 20 wtq ... my miata can not. My 5.0 also could afford 1000 rpms over factory redline, whereas i dont believe the miata can... i feel on the miata , mid range "should" matter more but then again this may depend on a track by track basis. That being said, looks like bolt ons on the factory VTCS manifold are probably the best bet at the moment, despite the fact it seems to fall hard on its face on the top end.

It does seem like any sort of manifold mods do essentially this ^^ sacrifice low end for top end. That being said, i could likely bump my VVT and / or timing up in the mid range to try to make up for it (and luckily we have good 93 in Houston), but again; more mixed results. There are those that say the VVT is optimized from the factory and to just leave it alone, but then there are those that say a stand alone tune is worth ~10 whp on a VVT motor. @ ~$1000, 100$/hp isnt exactly great gains on returns, but i suppose that is what it is, but it brings up more conflict.

I've seen other threads where a guy was dyno tuning his VVT motor and said this motor reacts very little to timing changes, be them cam timing or ignition, so we're back to square one ... hearsay. The rotrex needs a standalone to be done properly anyways, and really enough people have mentioned them now that i am strongly considering one, especially since they are a bit cheaper than i originally expected.

I will say, this is a very gray area as to what is "best" for making horsepower, so i really do appreciate everyone's input, and working through my thick headed stubbornness with me.