Chris Swearingen

iTrader: (1)

Okay, let's stir the pot some more.

Here is a chart comparing my ubercharger to a friends FMII. I am making about 14 psi he is only around 10, but peak power levels are the same.

kotomile

iTrader: (24)

You have the better plot overall, and the better setup for SM2. Only drawback really is that you run 4 psi more to make that power.

oreo

you can comment on how easy it is to get 240RWH with a supercharger after you have done it. For every 240RWH sc you see on these forums, you will see 6 or more turbo cars (and usually they are significantly higher hp as well). This is a reflection of the difficulties you run into going for this power level with a sc. I am aware of someone who had a 150/62.5mm setup, well tuned runing 250+hp, who broke 2 sc's, (he did track his car) before moving on.

EvoRoadster

iTrader: (1)

I went with a supercharger for several reasons. Most of my driving is in-town, from stoplight to stoplight, with very few freeway miles plus the main use of the car is for autocrossing. At the time it seemed both of these scenarios were better suited to a SC rather than a turbo. Having done a SC I do plan on going the turbo route next time just for the fun of it. Either are better than nothing.

ChairFaceChippendale

iTrader: (1)

truer words have never been spoken.

Rafa

iTrader: (22)

So, I read this thread and no one mentioned this guy: "FormerDatsun510Man". He is an m.net member. Here's a link to his setup: http://forum.miata.net/vb/showthread.php?t=265301

Hope it helps some of the SC guys.

jim-NA

When I was thinking of what sort of Forced Induction to get, my local Yoda came up with these words of wisdom...
No guesses which one I went for.....

socal pat

Sorry, but 168bhp is not big power. Truth is if you want big power there are better ways to get it than a Miata. Most people running turbos are between 180 and 225 whp. There are exceptions sure. I agree that squeezing 250+ whp out of a supercharger is more challenging than a turbo, but most people aren't looking for that end. Sheesh this argument is like who gives better head a blonde or a redhead. Wait.. I already know the answer to that.

Rafa

iTrader: (22)

Now you got me curious!

ChairFaceChippendale

iTrader: (1)

that being said, a good number of people on here do enjoy a challenge. that's why you see so many people piecing together home brew bits and running megasquirt rather than just bolting on a premade kit. yeah, money may be a factor there as well, but some people just HAVE to do it all themselves. and for that more power to them.

i do have to agree that i wouldn't be satisfied with a 170ish hp car. that would feel too slow too quickly.

and my money is on the redhead.

Joe Perez

iTrader: (8)

First of all, Redheads FTW.

Now, a couple years ago I found myself debating whether I should install a turbo or a supercharger system on my car. All of the anecdotal evidence I had suggested that superchargers offered much quicker response and better performance at lower RPMs, with turbos providing greater efficiency and top-end performance. The problem was that I had no actual hard data to back any of that up with, only a lot of rumor and speculation. "If only there were some dyno charts showing direct, back-to-back comparisons of turbo vs. a positive-displacement SC on the same car," I thought to myself... And then I realized that while said chart didn't exist per se, all of the raw data did, in FM's rather comprehensive dyno library.

As an thought-experiment, I decided to make a couple of composite dyno charts, in other words, overlaying data from one chart onto another, while maintaining scale. I chose to pull four charts for the '99, all taken on FM's old RotoTest dyno, and make two composites.

The first, below, is a U1 and a V1. Both were operating at the same maximum pressure, which I believe was ~6 PSI.





And next, a U2 and an FMII, again both at the same pressure (I can't remember what it was now, but I made sure it was the same):




So, I was not at all surprised that the superchargers had a slight torque advantage at low RPM. What did surprise the hell out of me was how early in the RPM band this advantage ended and the turbo pulled into the lead. In both cases, the crossing point is in the 3,000 to 3,500 RPM range, and the difference to the right of that point (turbo over SC) is much more dramatic than the difference to the left (SC over turbo).

In other words, the turbos provided a much greater "area under the curve."

That said, I still believe that turbo vs. SC is principally a matter of preference. If you haven't driven both, there's no way to describe it other than that they just feel different. I just thought I'd share these charts, in the expectation that others may find them as informative as I did.

924_nick

Your dilemma is kind of a win-win, so it's a good place to be. You don't hear too many people who go supercharger totally regretting it after words unless they're looking for ultimate power numbers. I'm running a DIY M62 at 8psi 167whp and I'm really happy with it. I have owned a turbo car in the past and I prefer the instant-on feel of the SC. To add a little to the discussion, I think the whine of a supercharger trumps the sounds of a turbo

The Crazy Swede

to anyone that has a s/c 'd miata...i'm absolutely in love with the sound of the supercharger that i hear on my brother's mustang, and i was just wondering if it sounded similar? he has a kenne bell 2200 supercharger on his GT. i was trying to find videos of a s/c'd miata, but i can't find many, and the ones i can find you can't hear the s/c. just wondering. if it sounds similar, i'll be going the s/c route for sure!
-Justin

Jefe

iTrader: (7)

I can here the S/C whine, over the 2 1/2" exhaust (JR stainless). Personally it's a little too loud...

Sentic

iTrader: (1)

http://www.youtube.com/watch?v=VoeAakp4RSo

rrroadster

Went to CMP in Kershaw, SC June 18-20.

Here's a pretty clean lap,

http://youtube.com/watch?v=KynpPfR23CU

My fastest lap for the weekend was a 1:52.035 by my Traqmate. Our AMB timing system had me at 1:52.039.

If the local dyno is open this weekend, I'll try to get a few pulls made.

KB

rrroadster

Went to the local dyno this weekend. I was disappointed with the results, which were 175 RWHP & 158 Ft-lb Torque. When had the car dyno'd last year, it made 200 RWHP. There were a lot of things different from last time, but I would have expected them to all be power adders.

Car Changes
Different Motor (105k salvage vs 113k salvage)
5th Injector w/Split Second Controller resulting in lower AFR (11 vs 12.5)
Coolant Reroute
Hondata Thermal Intake Gasket added
225/50/15 tires on car. 225/45/15 were previously mounted.
100mm crank pulley replaced with 110mm crank pulley (more boost @ 110/60))
EGR Delete
Idle Air Control System installed (may have been present at previous dyno - can't remember)


Dyno Changes
Different dyno locations(both were Dyno Jet - not Mustang)
Edited: Both pulls made in 4th gear.
200 ambient conditions: 75F, 100 Rel Hum; 175 ambient conditions: 88F, 60 Rel Hum

Could tires, ambient condition & Edited account for this much variance? I'll be doing compression and leak down tests later this week. I guess my first suspect should be the "new" junkyard motor.

On the upside, my quicker lap times aren't due to more HP!

KB

Sentic

iTrader: (1)

you did do the pulls in different gears.

Wittyfull

Does anyone have the VF supercharger which is the centrifugal type? I have driven both types of SC and the centrifugal type was slow to spool compared to the other.

axprotege

I went supercharger simply because I like the instant smooth power and its different than all the turbo miatas driving about. Built the car mostly for autocross and it works perfectly for that. I wanted big power with no lag so I put in a Ubercharger with a 15psi pully on a fully built engine and a link ecu and it flys. I assume its a bit cheaper to go turbo for big numbers and a lot more potential but im very happy with my setup and is way more fun in tight twistys.