With a stock 1.8, you have a lot more options out there for boost.... MP62 kits from BRP (hotside) or FF with the coldside. I've driven a CS car, Tom's in fact down at the gap. I am personally love the way it drove. That said, I do already have a BRP kit, and well, quite honestly, they have treated me well over the years, so I made the choice to stay with the hotside, and intercool it.....

However, you also have all the turbo flavours as well, including the DYI stuff.... so you have a lot of choices....

The best thing, is try driving different configurations, and see what works for you. They are all good, some just feel different.... and you have to make your choice. <G>

Dave,

Actually, a positive-displacement blower's power delivery is exactly linear, as it's driven off the crank. A turbocharger's delivery is typically progressive/quadratic.

Well, on the dyno torque is typically more linear than the supercharger, which makes more boost as rpm increases. At least that's the graphical representation. You probably know more than I do, but i thought a steady torque figure, regardless of rpm represented "linear" power delivery. Please elaborate for me.

I dunno I'm sure this guy is having a blast driving his FMII over the previous VF Cen. SC installed:

http://forum.miata.net/vb/attachment...chmentid=32973

Hustler: the definition of linear is a directly proportional relationship...1:1. With X amount of increase of RPM, you'll see X amount of increase in power/torque. Here's a linear, PD blower power curve: http://fastforwardsuperchargers.com/.../dyno-99-1.gif With every 500 RPM block, you're gaining ~25rwhp, from start to finish.

Now here's an example of a progressive power delivery, the old FM/BEGi setup on a 1.6L: http://flyinmiata.com/tech/dyno_runs/Buzz_010402.pdf Notice how, from 2500-3000 RPM, the car gains ~25rwhp, but from 3500-4000 RPM, the car gains ~50rwhp! Certainly not a 1:1 relationship. Now, once the wastegate's boost setpoint is reached, the power curve changes, and it should be much closer to linear after that, but it's hard to tell because the engine is close to redline, so the torque drops off sharply since the stock cams, intake manifold, etc. are being outflowed.

Many centrifugal blowers react in much the same way as a turbo, although sometimes not as pronounced, depending on what boost they're geared for. Check out how the stock S2000 torque curve (linear) contrasts to the Comptech centrifugal 'charged one here: http://www.comptechusa.com/store/med...percharger.pdf See how as the RPM's increase the difference in torque/power becomes greater and greater?

JayC: FM did deliver for a little while, I had the pleasure of riding in my autox buddy Gary's U3 Ubercharged 2.0 stroker, running 17 psi. It was DAMN fast but also DAMMMNNN loud. Since he has a daily to commute with and pretty much uses his Miata as an SM2 car, he doesn't mind the noise. I'll still stick with my turbo though for all the reasons mentioned previously.

I wouldn't bash the M45, but it all depends on what you want out of your car. If you want to road race or take it to the drags do turbo for sure. If you are into autocross I love the M45 - linear power and lower end torque mean less shifting and less bog off of tight corners. For driving around town I like my little M45. The only problem with it is what has already been said you will never make huge power with it. Before you buy anything you should go to a couple autocrosses or local club meets and get rides in blown cars. A turbo car will FEEL faster than a SC car of the same speed due to the turbo's woosh of torque at spool up.

Bottom line is that it all depends on what you like. I am a power junky and miss the turbo noises and surge of torque from my WRX, but I love my SC scream too. My solution is to take the M45 as far as it will go, sell the MP3, and buy an STi or an EVO when I graduate.

Ok, so would it then be appropriate to say that engine which make x# of torque which is essentially constant over the rpm band to diminish, if there is not increase in torque or hp with an increase in rpm?

thanks for clarifying this.

I don't follow your question. Can you word it differently?

Flipside is just about done installing an MP62 on a 1.6. There should be pics up on the site soon.

What's the going price for a used JR 1.6 kit? I haven't seen many for sale. Do they give really poor economy even when you don't beat on it?

Cheers

I've sold one a couple of years ago for $1400, I've purchased one for $1800 (with lots of extras), and I currently have another one for sale at $1400. I think $1400 is an ok price to pay.

No, gas mileage is not really poor with the SC. I'm not concerned about it in the least.