Question re the Answer - NB1 HP possibilities

Having recently bought my first NB Miata (1999 model), I am curious about reasonable options for increasing naturally aspirated HP. My goal for the car is occassional street driving, some auto-x (don't care about classing) and track (HPDE-type) work. For now, forced induction isn't an option. Knowing that, I'm curious what the recommended route is for HP gain, without spending a TON of money.

Current mods are: Racing Beat intake and a OBX header.

I found this post by Emilio/949 racing on the Miata forum. It helps, but isn't as definitive as I'm hoping for. I would love to hear from those of you who have gone down this path already.

150whp is bolt-ons and a good tune. Above that you need to go into the motor.
160-165whp is just a little bowl work and compression.
170whp requires more substantial head work or mild cams or lots of compression, pick one.
185whp requires mild cams (still streetable in a VVT), compression, porting. Pick two.
195whp full head work, lots of compression and mild to medium race cams.
205whp+ is pretty much a full race engine with cams that would probably never idle for street use.
225whp+ so and the life expectancy begins to shorten. Perhaps 15-30 race hrs and you're looking at a $15-20K long block.

There really isn't any way to add significant power without spending quite a bit of money. 110 at the wheels is stock, 150 may be doable with bolt-ons and a good tune, but it's not easy (well, not unless you've got as much experience at it as Emilio does, at least :) )

As for route, decide what your end model is for the car. Do you want to go forced induction eventually, or do you want to keep it naturally aspirated forever? Naturally aspirated will never make the power that FI does, but it will be easier to keep it cool and reliable on the track. If you're aiming for forced induction, know that most of the things you'd do to gain naturally aspirated power will need to be changed if/when you put on the turbo. There are more things that cross over to a supercharger, but relatively few people have managed to build high-power blower Miatas.

One thing that will translate is a good aftermarket ECU. The Hydra that FM sells is a good choice (albeit an expensive one), a Megasquirt is another good one (significantly less expensive, but will require a lot of learning on your part). I'd recommend one of those as a good first step, although if you need to pass emissions it will make things complicated.

As for what's possible, well, this is my NB1. It's neither cheap nor naturally aspirated, though. :)

Agreed that you need to figure out your eventual plans and figure how much you want to spend. 150 is not as easy as is always claimed, and probably involves E85, overnight parts from Japan (the Californians love those JDM intake manifolds) and a bunch of dyno time with an aftermarket ECU.

You can keep a turbo car cool and together on the track if you don't go bonkers with the power level and you pay attention to airflow. Specifically, getting air out from under the hood. 200 rwhp should be fine. The biggest problem with turbo track cars is that it's so easy to put just a little more boost in there. Driving with some mechanical empathy helps as well. Every time I suggest that, the swaggering always starts - but really, the best drivers are those who take care of their equipment. We generally have very little trouble with ours on track, but we're also driving to have fun all day instead of to win the track day.

That's good feedback. I was under the impression that 150 might be reasonably easy, but it sounds otherwise. Perhaps forced induction is the best route after all. 200rwhp would be fun.

Cordus - do you have a build thread anywhere? I'd love to see your recipe for 341!

Another vote for forced induction. If you haven't already, drive one and see that there's a good reason why so many Miatas have it.

nderwater wrote: Another vote for forced induction. If you haven't already, drive one and see that there's a good reason why so many Miatas have it.

That is sounding more and more likely. Given the low initial purchase, I'd like to keep the build as Challenge friendly as possible, which means cobbling together the parts I would need to turbo it. Anyone happen to have a relevant build thread to direct me to? I know MiataTurbo.net exists, but would rather stay within the friendly confines of GRM.

dyintorace wrote: That's good feedback. I was under the impression that 150 might be reasonably easy, but it sounds otherwise. Perhaps forced induction is the best route after all. 200rwhp would be fun. Cordus - do you have a build thread anywhere? I'd love to see your recipe for 341!

200 rwhp with a turbo is pretty straightforward, Keith can set you up with a kit to do that.

341 on my car comes from a built bottom end, P&P head, FM2R kit with GTX2863R, 3" exhaust, big injectors, MS3 computer. I've got a build thread on miataturbo.net (here)

Do some very skeptical research before deciding to roll your own. Like a lot of things, enthusiast forums can gloss over the difficult stuff and make the job sound much easier than it really is. Put together a good budget. Make sure you're paying attention to what it will take to make the car start in cold weather, to have proper AC compensation, to have a nice smooth power band with a good margin of error.

It's not uncommon for us to be talking to an owner who decided to build their own turbo kit, and when they were done it would have been less expensive, easier and more reliable to pick up a well-engineered and debugged system off the shelf. We do sell partial kits if you have your own ideas on things like engine management or want to source your own turbocharger.

Check out garage quinn motors, Quinn is making good power in his naturally aspirated nb.