NA Miata, Supercharger vs Turbo?

I'm already planning this as my next winter project. I'll likely just do a stockish rebuild on the 1.6 in search of 220-250whp......which seems to be where a lot of turbo kits put the 1.6.

But I've always loved the whine of a supercharger, but there are definitely fewer 1.6 kits for the NAs vs the 1.8.

The BEGI supercharger kit looks interesting, but no option for an intercooler means water/methanol injection...........and I'm not sure if the you can use an underdrive pulley to up the stock boost from 5psi, to say 8-11?

Any insight you guys would like to provide?

I've also thought of a homebrew turbo vs a kit, but to use quality components + locating all the odds and ends, I always figured it would save money to increase hassle.

I don't think i've seen many M45s above 150whp on a 1.6.

You can add an intercooler to a supercharger kit, as far as i'm aware.

It's going to take a LOT of work to get an s/c 1.6 to 200-220whp.

Rotrex would do it easier than a Roots.

^The BEGI kit is a "cold-side" supercharger, in other words, its on the intake manifold side of the engine vs hung over the exhaust header.

ANd is an MP62 vs MP45.

If you're after the whine, you don't want a Rotrex.

The M45 simply starts to run out of breath fairly quickly, and you hit the point of diminishing returns fast. You're not going to get the M45 to 200 rwhp, it'll peak (after lots of cash) in the 180 rwhp range.

Here's a direct comparison between a "big boost" M45 and a standard FM Voodoo II turbo: http://www.flyinmiata.com/turbos/janel.php. What you don't see on the dyno chart is the much improved driveability of the turbo over the M45.

Adding an intercooler to the M45 only exaggerates the driveability problems.

As for the BEGi kit - a quick look at how the fuel delivery is handled sums it up for me. Compare that to the fuel delivery system on a 1977 VW bus, and then think about their tendency to burn to the ground. Plan on a bit of extra time to get all the parts and to get them to fit, too.

92CelicaHalfTrac wrote: I don't think i've seen many M45s above 150whp on a 1.6. You can add an intercooler to a supercharger kit, as far as i'm aware. It's going to take a LOT of work to get an s/c 1.6 to 200-220whp. Rotrex would do it easier than a Roots.

Another drawback is that a lot of the hotside supercharger kits move the throttle to before the blower. Unless you change things so there's a second throttle in the stock location (I'm not aware of any kits like this, but there's a lot of homebrew ones), you end up with a huge amount of throttled volume that makes idle control difficult, and intercoolers tend to exasperate the problem.

With such a small motor, I'd go turbo. I wouldn't expect it needs much pressure to get up to or above 200 hp especially if you can fit in a front mount intercooler, but with the supercharger, keep in mind you are taking power to make that power.

Anyone know how much pressure that motor can withstand? Other mods you have will have to be taken into account.

The limits aren't so much pressure as power. 6 psi on a big turbo can be just as much power as 15 psi on a little one. 230 rwhp is a good target with proper engine management and a lifespan measured in decades. I think the record is 19 years and 350k miles or so...and counting.

In reply to Keith:

Good point. Now I know it is possible, but you're the master of that beast, Keith. Let me know when a Skyline needs an upgrade.

I bought my kit from BEGI awhile ago. Great kit. But if I had it to do over again and I wanted a kit...I'd go Flyin Miata. They're customer service is miles ahead of anyone else in the business. You will not be left dissatisfied buying from them.

Also, I'd avoid www.turbomiata.net. I was there a few years ago and it's a bag of a$$holes. Literally. It's the most unfriendly, unhelpful forum I've ever been to. I've never been banned from a forum. I was banned from there about 3 times. Avoid, avoid, avoid. Miata.net has just as much info and is much kinder to new guys asking questions. I'll temper my position by saying maybe it's changed. Maybe the jackholes who allowed the place to be that way moved on. Yeah, maybe the Middle East will one day be a giant playground.

To your kit..I think a small turbo is going to do more with a 1.6 than a supercharger. I had a small garrett on mine and it had full boost by 2800 - 3000 rpm. Lag was just about non-existent. 200 hp estimated power. I never dynoed it but the 0-60 times calculated against weight were close to that number.

I ran a megasquirt and it took me awhile to learn how to tune it. It worked really well after that. The learning curve was pretty steep for me. In the beginning I wished I had used a piggyback like FM's voodoo box so that I didn't have to spend as much time tuning as I did. By the time the car was totalled it was running really well. I'm not in anyway saying MS was a problem. It wasn't. I just wasn't used to tuning my car-puter.

Just curious here..what's your goal with the car? Street antics? HPDE's?

I was also banned from miataturbo, for not responding to the email re my membership request in a timely manner!!! An email I never received by the way. The jackhole signed my ban notice 'love, philip'. That site is a HUGE waste of time. Miata.net and Keith are by far and away your best resources.

I wanted to rotrex my rallycar in the worst way but man oh man they're sooooo expensive. Keith and co. are the ones to go-to on this.

Flyin' Miata turbo kit. Just do it.

Did everyone miss the size of the supercharger?

How much more air will an M62 flow vs M45?

Keith, I agree with you on their fuel management.

I know I'll likely end up turbo, but I've always loved that supercharger sound.

The MP62 will flow quite a bit more air - they top out in the 240-260 rwhp range. That's not necessarily the limit of the engine, but of the blower.

The BEGi kit is the only MP62 option for a 1.6. All the others are M45, so that's why I addressed them as well.

When I pulled the blower off Janel's car, she did miss the noise. And when she hears a 12 psi Übercharger at full song, she gets all nostalgic for it. But when I suggest we switch back, she gets aggressively possessive of her turbocharger.

Hmmm, OK. So it would work for the power goals, but would take a properly tuned Megasquirt with meth/water injection to hit it.

Cost for cost, probably about the same $5500ish.

With a S/C, could you even pull enough timing to be safe, in the event of your water/meth injection system failing?

Good question. Probably not - an MP62 working that hard has some pretty hot outlet temperatures. And you can't limit the boost on a SC either, although a fuel cut would probably do the job nicely if the MS can do it.

If you want a blower get a blower, but it's unrealistic to expect 250 WHP out of it or a turbo for that matter. Don't focus on dyno #'s either, they vary a lot. Try to mooch a ride in each type before you make a decision.

To parrot Xceler8 - what are your intentions? Scooting around on the street is a very different demand than flatfooting around a track, so pick your options carefully. Engine management, oil & water cooling, hardware & heat shielding all become much more critical ($$) if you plan to hit the track no matter which way you go.

Another drawback is that a lot of the hotside supercharger kits move the throttle to before the blower. Unless you change things so there's a second throttle in the stock location (I'm not aware of any kits like this, but there's a lot of homebrew ones), you end up with a huge amount of throttled volume that makes idle control difficult, and intercoolers tend to exasperate the problem.

There's a reason people dont put throttle plates behind positive displacement pumps. Although you could run one of those super noisy dump valve things like centrifugal blower people sometimes do.

Also 250whp in a miata is way overkill vs what most people actually want from a performance standpoint. 200hp in a miata feels a lot better than it sounds.

Also, an underdrive pulley would LOWER boost vs stock. To get more boost you need a BIGGER crank pulley (or a smaller SC pulley which is the usual approach, less side effects).

Keith wrote: Good question. Probably not - an MP62 working that hard has some pretty hot outlet temperatures. And you can't limit the boost on a SC either, although a fuel cut would probably do the job nicely if the MS can do it.

MS has an option to cut fuel for use as rev limiter. I'm not sure if this what you're referring to. MadScientistMatt could answer that better than I could.

Dashpot wrote: what are your intentions? Scooting around on the street is a very different demand than flatfooting around a track, so pick your options carefully. Engine management, oil & water cooling, hardware & heat shielding all become much more critical ($$) if you plan to hit the track no matter which way you go.

Listen to this. My car was rock solid on the street. It was even great up to 5psi on the track. When I went to 7psi it started to overheat after 15 min's on track. I had some work arounds but I knew they wouldn't work to achieve my goal of a track reliable 10psi of boost. Funny thing, the cooling problems didn't show up on the street at all. I could've driven the car with a stock rad and coolant route all day. The track is a much harsher environment.

Just to give an example: I knew I had cooling problems so I was trying to find a way around my temp issues with cheap fixes. Bigger electric fans, new stock sized automatic rad, and rerouting the coolant were what I tried. To test before my next track day I drove in the VA summer (100+ degrees ambient) in fourth gear for 40 minutes at 70 mph. That comes out to a steady 4500 or so rpm. I figured "Hey, that's what I do on the track. It should give me some sort of data as to whether my fixes will work right?" Wrong. I was revving my motor up for an extended length of time but I wasn't under load so therefore very little boost. For a proper test I learned that I needed to have high rev's and high boost for extended periods. Needless to say my fixes didn't work at the track. The final fix was the largest mishimoto rad I could fit in place of the stocker.

The track environment is very, very harsh. Much harsher than just about any street environment assuming you care about felony traffic convictions.

I was referring to a rev-limiter-style fuel cut if a certain parameter gets out of range. For example, the old Link used to do that if either air temp or water temp got over a certain limit - it would limit the amount of load on the engine until things got happy again. Basically, a limp-home mode.

BTW, there are much better rads and fans on the market than Mishimoto. They're affordable, but not what I'd choose if I was looking for maximum cooling. Especially the fans. But yeah, cooling is the biggest challenge for a turbo Miata on track.

Current MS firmware won't cut fuel if the IAT temperature goes over a certain point, but you can set it to pull a lot of timing and add more fuel when that happens. And you could use something like a level switch to turn off the fuel injector power if the water injection reservoir runs out.

Yeah, it wouldn't have to be triggered by IAT. More likely you would trigger it from a flow switch on the injection system. That's how we switch between water/meth and normal maps on the Hydra. Safer than a level switch because it also accounts for pump problems and clogged nozzles.

The current MSPNP has a general purpose table switching input that could accept a flow switch input.

Keith wrote: BTW, there are much better rads and fans on the market than Mishimoto. They're affordable, but not what I'd choose if I was looking for maximum cooling. Especially the fans. But yeah, cooling is the biggest challenge for a turbo Miata on track.

how would you address this?

FM Crossflow rad, with their shroud and big dual fans, and heavy duty oil cooler. Probably some hood vents as well.

X, I'm well aware of the much harsher environment the track presents.........especially considering a track day in June-Sept in OK will usually = 95+ temps by noon and 100 (as high as 110 last year) in July/August, and that's just air temp.

This thread was meant for a S/C vs turbo debate, not the other stuff, I've already got a plan for it.