RED MX5

I also recall that Comptech had some problems with the supercharger bracket breaking on some early systems. Haven't heard any similar stories about Vortech, but that doesn't necessarily mean they didn't have some issues with the early production units.

Actually, I (showing my ignornace) thought the Vortech kit used the back box to achieve fuel enrichment. Do you have any idea why they don't just let the knock sensor pull the timing? When I upped the boost on my Yamaha 650 Turbo from 7.5 to 15 pounds the stock knock sensor handled the timing perfectly. Does our ECU have some kind of issue that makes using the knock sensor to pull timing unsafe?

RED MX5

Yea, but I do my testing and tuning with data logging rather than at a drag strip, and nobody seems to put much faith in performance data derived from logs.

And ... As far as I am aware, I'm the only monkey in the zoo with 4.30 gears.

Slows2k

The PCM still can retard ignition timing via the knock sensor, and it does. The engine still has to knock before the sensor feedback lets the PCM know to retard the timing. Not to mention the increased engine noise the SC creates. No one has bothered to log the change in knock sensor output with and without a SC installed.

Call it active timing retard, so you aren't slowly detonating the engine.

Slows2k

I'm just giving you

And as anyone has been on a group drive with me knows I'm not the fastest monkey in the zoo...

xviper

Taking the drivers and the street racing environment out of the equation, here's what I think ...................
4.3 gears give you a 5% bump in gearing. Let's say the Vortech runs 300 whp. If your Comptech were pushing 285 whp, I would say the 2 cars would be very close.

s2kzorz

Are most of you who went with either supercharger happy that you did that instead of turbo? Would it be smart to go right to a FMIC with either system instead of getting the SC/AC combo for either kit?

Slows2k

A FMIC with a stock SC kit is a good way to loose 2-3 psi of boost, and not much else. The additional piping, and pressure drop on a low boost system isn't a good idea.

The non aftercooled Comptechs do quite well on 6psi, as do the Aftercooled Comptech's and Vortech.

RED MX5

I think the ECU retards the timing and holds for a period depending on knock intensity, so it does't actually have to ride the kock limit allowing constant low level knocking. I know for sure that this is the way the knock sensor and timing control worked on the Yamaha 650 Turbo. Seems to me that if the ECU allowed slow detonation there would be issues when lower octane fuel was put in the car (not that you or I would be doing that, but the car should run fine on dirt cheap regular, though it will be down on power). Am I getting this wrong?
(That is most certianly possible. )

I can log the knock sensor and timing pull with my PLX logger, but it will have to wait for a bit because I'll have to do some rewiring, and I've got to leave it as is until we get the exhaust system sorted out. I don't have *any* kind of feel for how well the DSP filters out exteranious noise picked up by the sensor, but we can probably get a fair idea by looking at the raw sensor output and the timing pull. You might be right about the supercharger interfering with the knock sensor, but if that's the case we should see the timing pull when it's not actually necessary.

Now I wish I'd started logging stuff with the PLX BEFORE we put the SC on the car.

RED MX5

Yes, absolutely! While it is in large part a fortuitous and unexpected synergy, the mods we have done to my car up to this point suit me to a T, and the car is exactly what I want it to be at this point. The only place I do any real racing is on the autocross courses, and as long as I'm winning there it's going to be hard to be dissatisfied.

I absolutely love the way a stock S2000 makes power, and one of my goals, from day one, was to accentuate the dual nature of the car. A centrifigual blower does just that, leaving the car feeling near stock below VTEC, while making the VTEC surge far more pronounced. I love that aspect of this car, and a centrifigual blower just gives me more of what I like. A turbo would be quicker, but my car is for me and is being modified to suit me, and I *LIKE* the way the blower and VTEC make all their power at high revs. Don't want it any other way.
(At least not for now.)

If I had it to do over again I wouldn't change a thing.

xviper

I haven't for a single moment, regretted going the Vortech route. I bolted the thing on and it's been serving me well for many years. It's my daily driver and I've never had any significant issues with it. It's been many 10s of thousands of miles and I'm still on the original belt.
The turbos of the day would have been a total nightmare. Although we do see the turbo kits of today being far more superior to yesterday's products, it can't yet be said that they are reliable for many years and high miles of use without needing something during their lifespan. Having a "Turbo" S2000 may sound very exotic but after years of day to day driving, all you really want is reliability without worry. Perhaps in the years to come, this statement will have to be revised. If you want instant gratification with no regard to where your car will be at in a year or two, get a turbo. If you can be satisfied with what a stock S/C kit will give you and all you want is to bolt it on and go, get the supercharger.

You can always get the FMIC "look" by replacing the stock aftercooler radiator with one of these:

It doesn't perform any better than the stock unit, but it definately makes onlookers wonder.