kyle242gt

Hi all- Just stopping in to say hello and ask a few questions.

My wife has gotten the HPDE bug, and wants a Miata. Who am I to argue, I've wanted one of the little things since 1989. But since we have five cars already, something's gotta go... and it looks like it'll be my DD ('94 BMW 325ic).

No sweat, I'd like driving a Miata every day. But I've known myself long enough to know that I'll want more power. Lo and behold, turbo!

My previous DD was an 80 Volvo 242 which I turbo'd and megasquirted, so I know my way around turbo retrofits. But one of my beefs with MSnS-E was the niggling little drivabilty tweaks. When I went to the BMW, I relished the easy starts and excellent idle.

That brings me to my question, and this forum seems like the right place for it. What are most DIY'ers doing for low-boost DD setups? I like the idea of simple bolt on with IC and FMU. I can't get away from thinking GReddy=rice, and would like to stay away from emanange... but if EMS is really the way most guys go after struggling with bolt-on, I may as well go that way from the start.

Another reason to go bolt on, though - I can see this car (which I haven't even started shopping for in ernest) being a SpecMiata car, so I'd like to be able to bring it back to stock easily.

Lastly, is turboing a 1.8 significantly harder from a DIY perspective? I like the idea of upgraded brakes, chassis, and LSD in the 94-5.

Many thanks for any feedback

Newbsauce

iTrader: (2)

For daily driving, you would probably want something that spools pretty quickly. I would research the t25 on this forum, as its a turbo alot of people use and is quite cheap to source and easy to rebuild (see samnavy). I personally am a big 1.6 fan, but I don't see any enormous obsticles to turboing the 1.8. As a matter of fact Turbotim managed to twin turbo his. Please keep in mind, those upgrades you mentioned are just as easy to source and put on a 1.6. If you can't tell.. I love my 1.6 Good luck, and search away.

samnavy

iTrader: (7)

You're definitely in the right place. Forgive me if I mention something you already know.
There are a few main differences in considering NA(90-93vsNB(94+). You've discovered brakes and dif which are the main mechanical differences.
For a complete rundown on all things Miata, check
Here: http://www.miata.net/garage/
Here: http://www.miata.net/faq/

If I remember right, the main dif's starting in '94 were the elimination of the flapper-door style MAF to a MAS... less intake restriction and way easier to incorporate into a turbo setup. In '96 the car became OBD-II which presents some problems. Also there's something about '94+ cars fuel plumbing (returnless or something) being different.

Most guys will probably say that if you're buying one with the intention of turbo'ing it, a 94-95 is the best bet due to it being OBD-1. Having A/C and P/S presents some piping issues for intercooler mounting and puts an extra 50lbs or so out in front of the front wheels. A lot of guys remove the A/C altogether and swap out for a manual steering rack.

The 1.8's make a little more power stock, but the debate rages whether a 1.6 or 1.8 makes a better turbo candidate. Both are capable of pretty much the exact same power gains per any given amount of boost.

Just about the only thing in any given turbo kit that isn't interchangeable is the manifold. 1.8 and 1.6 mani's are different. The two main players in the turbo game for Miatas other than Greddy are Begi and FlyinMiata. Visit their websites and become familiar with their products as they are truly the benchmarks. There are a few other companies that you might hear. Mazdaspeed itself makes turbo parts, also a company called AVO... and a few others.

Whatever you do, you will need a new clutch, expecially if you're planning on any track time. ACT, RPS, SPEC, etc... are all good.

kyle242gt

Thanks guys, appreciate the feedback. Good to hear that the 1.8's aren't no-go for boosting; I'll just keep my head down and keep waiting for the perfect 94-5 to roll across the horizon.

Any thoughts on turboing an OBD2?

Al Hounos

I don't see any problem with obd2, except that you live in CA. i don't know their laws so i can't help you.

But if you are experienced with MS, why not use it on the miata? It is (IMO) the best option out there for turbo miatas.

1.8 is definately better. I have a 1.6.

kyle242gt

re: OBD2 - was wondering if RRFPR (FMU) and O2 clamping would set a code and put it in limp mode. Smog doesn't scare me, I have a couple buddies in The Biz.

re: MSnS-E, after reading this really great thread and tracking down info on the Bipes and FMU, I might just dust off the old laptop and give it a go again. I didn't much like the hairpulling exasperation of getting the spark triggering sorted, and the little drivability gremlins sucked. On the other hand, running 15psi on 87 octane was a pretty sweet sensation.

Mostly, though, I need to keep in mind this car's destiny (say it like Darth Vader) - fun daily driver for a year or two, then likely conversion to SM. So I need to be able to easily bring it back to stock for racing.

My Volvo was formerly K-Jet (mechanical) and it all got ripped out when I went EFI/MS; the only way to sell it was to find a fellow enthusiast. With the Miata already having EFI, if I can bandaid my way to 150-180WHP and keep it bolt on (and therefore bolt-off), I'd love to.

On the flip side, spending $400 for bandaids that don't really give me the tunability of MS would kinda stink, since I can certainly build my own MS again.

Still shopping, still lurking, but definitely listening to all y'alls input.

Al Hounos

If you use a plug nplay harness like the one kingofl337 is selling, I'd think it woluld be a lot easier to uninstall than bolt ons.

kyle242gt

Thanks Al! I've spent the AM reading the MS install threads, and the PnP like Kags put together seems like a sweet way to go. Gotta keep the door open for SM dontcha know! For $20, the boomslang harness looks like a great idea. From kingof1337 signature, it looks like the 94-7 PnP is still in progress.

That tears it. Now I'm officially excited. Verily this will be the best car ever.

magnamx-5

iTrader: (7)

oh yaeh a ms expert maybe they will go mainstream.

Markp

You want either the 99/00 Sport (w/Torsen), 00SE/10th AE Miata (6speed with Torsen) or the 94R or 94/95 Leather package. You don't want a 97 STO (Stuff Taken Off, like the Torsen LSD)

Here is why I say what I am saying...

1. The 1.8 Torsen is much more boost friendly.
2. The 6 speed is the strongest factory transmission ever installed in a Miata
3. The 99/00 Head flows the best.
4. The 99/00 will outhandle the 94/95
5. The 1.6 Miata LSD is easy to break.
6. The 1.6 needs a smaller turbo to spool as quickly
7. The 1.8 motor has a 12% advantange in displacement (and in power.)
8. The 99/00 motors have solid lifter cams
9. The 5 speed in all Miata's is good to about 250 RWHP +/- 25HP
10. The 1.8 motor is as boost friendly as the 1.6, both were originally turbo motors.

Mark

olderguy

iTrader: (19)

Thanks Mark, very concisely put. Where was the 1.8 originally a boosted motor?

Markp

Miata does not go into "limp home mode" like a Honda. It will code and ignore, or run it's open loop map. What you want to do is run the MS ECU in parallel with the stock ECU.

The stock ECU has no idea that you have disconnected the coils and injectors. With the 99/00 Miata you retrofit a 94/95 cam angle sensor for the MS unit to have it's own trigger and the stock ECU continues along as if nothing happened, happily pulling it's outputs to ground with nothing happening. Still it will control all the other stuff you don't feel like controlling... fuel pump, alternator, reading the factory knock sensor, running the EGR port.

I know I have only a few posts here, but I know a thing or two about how to skate around cali emmissions with a Miata running an aftermarket ECU.

Mark

kyle242gt

Thanks Mark - I wondered about doing that. But that means either cutting the factory harness to disable the OEM ECU control (spade terminals, not a big deal) or running a new harness (also not a big deal, but messy).

I liked the idea of PnP, but I see the wisdom of leaving the OEM ECU in charge of non-performance based stuff.

Having come from the land of the glass transmission, I don't want to run into drivetrain limitations again...

The 1.8 seems like a no brainer for the bigger diff, and my spec sheet says the Torsen came on 94-5 (except base model) 96 PEP and better, and 97 PEP, leather, R, and M. Good point on the STO, as I surely would have assumed it was so included.

250HP (+25% since I'm actually starting to drive like an adult) would be more than enough power for the street, and way to much for the track.

I prefer the NA body style, and 99+ is gonna be pretty rich for my blood anyway... and NA will certainly handle well enough to rock my socks on the street and keep my wife entertained on the track. Plus, in my experience, more boost is a good substitute for inferior heads and manifolds

Markp

1990-2005 5 speed Transmissions give up around 250 ft/lbs of torque... sometimes less. This has been tested OVER and OVER.

1999-2005 6 speed Transmissions seem to be holding up past 300 ft/lbs but less than 400 ft/lbs of torque. The limits have not been firmly established yet. Several Miata's have been in the 400 RWHP range, only one has clearly shelled a transmission and did so at 600 RWHP.

The six speed doesn't even flinch at 250 RWHP, even drag racing and abusing it.

Mark

The 99/00 head is worth about 20/30 HP at the same boost level with an identical turbo kit.

Markp

1990's 323 GTX, GTR, and GTAe

Mark

Markp

Actually, you don't have to cut anything to wire in the aftermarket ECU in parallel with the stock ECU. At least not on the 99/00 and if you are creative on the 94-97 you can do it without cutting a single factory wire... At least I can... It does require a little bit of trickery... but I can do it... so you can do it. You might have to install one or two vampire taps... but really now is that so bad.

Mark

kyle242gt

Thanks a lot, Mark. Your comments are really helpful.