SignOfZeta

Hi, this is my first post here. Nice forum, not too uptight, etc.

My 92 has nearly 200k on it and I've got plans to re-build an engine for it. I've been thinking for the past year about plans for a 150HP or so NA engine. 1.8 block, 99 head, 10.5 to 1 pistons, crazy cams, ITBs, 9000RPM, etc. Recently though I gave it some honest thought though and realized that...realistically, this just isn't that great of an idea for several reasons. The main reason is the popularity of turbo Miatas. Turbo Miata's outnumber truly built NA ones, what, 100 to 1? There just isn't enough real reliable info and real reliable parts out there for me to build an engine like this with confidence. The turbo scene on the other hand is alive and well though with gobs of info and some good parts suppliers.

Since my goal is only 150HP, its seems like it would actually be cheaper to do this with a turbo than without one. Also, more reliable, driveable, etc.

So here is what I want: 150 HP, or something that. Car is currently a year round daily driver but will soon be retired from winter duty. I want something reliable and not very expensive.

Here is what I have: 1992, driveline hard parts are totally stock. Currently running Megasquirt II (DIYPNP) with 1.8 injectors.

Here is my tentative plan: Rebuild a spare 1.6 totally stock and start with something like the BEGI 1.6 Starter Kit.

Can I safely get 150HP with no intercooler and 5psi? I live in Michigan, btw, so I don't have too brutal ambient air temps.

A few other questions.

Regarding the two different manifolds from BEGI (cast and stainless tubular). Is there any reason to not get the tubular one in a low end set-up like the one I'm going for? It seems like they built it for higher power cars but...its pretty and won't rust, so I'm interested.

Will 1.8 injectors and an otherwise stock fuel system be enough in that department?

Water and oil lines for the turbo seem to be stupid expensive from FM and BEGI. Is there any reason I couldn't making these myself, or is the hassle worth $200?

buffon01

iTrader: (9)

Here you sport:

http://miataturbo.wikidot.com/

https://www.miataturbo.net/diy-turbo-discussion-14/diy-faq-all-your-answers-one-big-post-4288/

wittyworks

iTrader: (6)

Well you have the first thing done right, getting a megasquirt installed and set up first, congratualtions!! You seem to have your priorities set straight, that will definitely help you out on here.

You can get 150 with no ic and the 1.8 injectors, and as everyone on here will tell you, you WILL UPGRADE in the future, you WILL WANT MORE. If you have the cash for the begi tubular, then go for it. And look at ARTech's oil and water line kit, do a search for it, much cheaper and its a great kit.

A better idea for the engine is to just set up the turbo right now on your current engine, and start building a BUILT block for when you do turn up the boost and want more, the stock engine you have now will run forever on only 150 as long as you have a good tune.

Preluding

iTrader: (10)

If 150 is all your want... keep the engine you have and find a used greddy kit for well under $1000 bucks and a rising rate FPR and wideband.

You'll want more though... see post above for that one.

ianferrell

No need for a rising rate FPR as he already has megasquirt, and surely a wideband already.

SignOfZeta

Yeah, I have the (somewhat disappointing) LC-1 wideband.

buffon01

iTrader: (9)

Plx 300m ftmfw!!!

rider384

iTrader: (3)

I have no ******* idea why I got an LC1. It's bullshit, you have to recalibrate it every couple thousand miles and you have to wait for it to ******* warm up.

hustler

iTrader: (6)

My LC-1 works great all the time.

If you nly want 150whp, you want a 10.5:1 NA motor.

Yes, the turbular manifold is worth the money.

Yes you can build your own lines, some people have the skills some don't. I have the skills, I'm virile.

webby459

iTrader: (8)

If you only REALLY want 150whp, why not just do a stock but well tuned '99 1.8 motor with I/H/E-~140whp, and take some weight off the car. The effect will be the same, and you'll save lots of money.

SignOfZeta

I've never seen a wideband that didn't have a warm-up period (the Horibas at work take twice as long as the LC-1) and recalibration is no big. My problem is that the thing has a really crappy heater circuit. If I cruise on the highway at light loads and the EGTs get too high, then when go down an off ramp the LC-1s heater can't compensate for the rapid change in temp and it throws a timing error, forcing a reboot. This is with my %100 stock exhaust, engine, etc. Its fine if you are just wailing on the engine, it only happens when you go from a long cruise to a closed throttle decel.

I'm hoping that my cat is more plugged than I think it is, and replacing my entire exhaust over the winter will help with this. Also, whatever my next downpipe is, the sensor will be further downstream.

Which reminds me, what are people's opinions on outlet/downpipe's from FM versus BEGI. They are rather different, but they both seem to know what they are talking about. Do the BEGI downpipes actually crack all that often?

SignOfZeta

Would I really save a lot of money? On a good day I can get a spare 1.6 for $300...and, while I know this is hard to prove, they seem to be more durable than the later stuff. Also, what intake? Lose weight...from where? In order to make 140HP into 150 I'd need to lose something like 300lbs. From where? I do have to drive this thing on public roads. I'm 2 hours from the track with no trailer.

Since I already have standalone I'm looking at about, my guess, $1700 to turbo a 1.6, and the turbo route leads to all sorts of possible expansion in the future. All things considered, its close, I admit, but the turbo comes out slightly ahead with more low end torque, cheaper parts, expandability, and a lower redline requirement. Plus, once I replace the 1.6 diff I can slap an intercooler on there and go for even more power...hard to do that with an NA.

Also, the Detroit Michigan SCCA has no CSP cars except me now. I might as well move to SSM

Honestly, if money were no object I'd have a spare car with some insane Maruha 240 HP NA engine in it, but I only have so much to spread around, money-wise.

Chiburbian

iTrader: (1)

I am pretty much a noob (lurking for the most part thus far) but from what I understand, 240 is not exactly insane numbers. Much better informed peoples will be responding soon I expect, but insane to me would be in the mid to high three hundreds in HP. 180-240 is good spirited daily driver... am I correct?

EDIT: To clarify, I am referring to a 240 HP NA series engine, a 240 horse Naturally Aspirated motor would truly be insane...

SignOfZeta

Yeah, I meant naturally aspirated. An insane blown Miata engine would be 600HP or so.

WonTon

iTrader: (17)

no! the majority of this forum is in the 225-320hp range. i mean for **** sake, have you riddin in a miata that has 250hp? its pretty nutz! anymore than that and traction becomes an issue!

SignOfZeta

Hence my use of the word "insane".

http://www.youtube.com/watch?v=6bSq2nns22Y

WonTon

iTrader: (17)

yeah and BTW! thats a 2.0L stroker BP and that car has ungoldy amounts of money put into it!

those HP levels are ungodly, if you put some random *** fucked retard in the seat of a 250hp miata, you know what his exact word will be when the ride is over?

"THATS INSANE"

jesus man, i heard those words at sub 200

miata2fast

iTrader: (2)

If you decide to do an N/A build, I could steer you in the right direction.

N/A motors are not cheap to build, but a N/A car with the same horsepower as a turbo is faster than the turbo car. I estimate my N/A makes around 170 - 180 horsepower but is getting pretty close to 12's in the quarter mile.

You have to ask yourself what you plan on doing with the car. High horsepower N/A's are not exactly daily driver worthy compared to a turbo car with the same or much more horsepower. When racing, an N/A is very reliable compared to a turbo car.

SignOfZeta

Yeah, that's my thing. This car has to do just about everything, and from what I can tell turbo is better for that sort of thing.

Cococarbine3

iTrader: (1)

Hey, welcome to the forum. You helped me out a lot on my engine build a long time ago at m.net.

It looks like you are almost there... you just need bigger injectors, a turbo, some oil/water lines, and some piping. Other options aside from FM or begi are some of the sponsors here that have done manifold/exhaust setups for several people here. IE Absurdflow, SKMetalworks, and ARtech all do awesome work from what I have seen. If you get lucky, you can find good deals in the classifieds here too.

As for your goal, you really shouldn't rebuild your motor to stock unless you have seriously poor compression. You want to wait until you get forged internals so you don't go through all the trouble twice, because we all know you're going to shoot for more than 150hp with time. That, and it's just not necessary. You should be able to reach around 150 with no intercooler, just keep an eye on your AIT and make sure you don't have any knock. At 5 psi I would play it safe and install a BOV also. Good luck.

Oh yeah, Michigan lost to Iowa today... my friends won't stop giving me crap about it