Thanks for the in-depth analysis of my report. I keep learning from listening to all you guys.

At 6k RPM (torque peak), duty cycle is 65% and manifold pressure is 133kPa. DC doesn't hit 75% until 6670 RPM, 140kPa.

I didn't even know what MBT was until seeing comments in this thread, and the other on Miata.net, but we did tune for max power at various engine speeds. We spent most of our time tuning at full throttle, and I will be sure to hit more part-throttle cells during the next tuning session. Having never tuned a Rotrex supercharged car before, the tuner was a bit apprehensive about being so aggressive with spark. After some encouragement, he added spark until power started to level off, then we scaled it back by a couple of degrees. He left the 160kPa cells with less advance at high RPM as a safety factor. I suspect we could add some timing back in up there for a little more at the top end.

It's reassuring that others with Rotrex superchargers have been able to be this aggressive with spark without knock. We did not hear any knock at any time, and careful inspection of the spark plugs did not reveal anything of concern.

 

Hasn't stopped me.

 

You need it though. Otherwise things in go pop that aren't supposed to.

I don't think I'll need it... 2.0L big valve fully ported, .430 lift, ceramic coated everything, internals safe to 8500, 949 header, 2.75" exhaust, square top, sequential ignition COPs, 12T crank trigger and a C30-74. It'll probably make 320whp on a strong cup of coffee. I think that's sufficient to accomplish the goals I have in the OGK.

 

Thats pretty impressive.

 

When is the KW3 setup coming out? I'm looking to make around 190 - 210 whp on a stock 99 engine. Any pricing ideas?

 

Not sure what base intercooled NB kit will be called but it should make about 185whp on pump gas right out of the box. That is the limit of the stock injectors/fuel pressure.

If you choose to remove the restrictor, add bigger injectors and a programmable ECU to control it, a stock 99 engine with header, high flow cat and exhaust would probably make around 260~280whp with the upcoming intercooled NB kit.

 

Sorry I didn't specify, I am in a racing series where there is a limitation on power. No problem on buying bigger injectors or a standalone. Also, don't want to make too much power because as referenced in another thread, i'd rather have a 2000hr motor than a 20hr motor . What I'd like to avoid is buying additional parts I don't need like exhaust, etc..

Also, is there any way to change the power curve of a supercharged setup? I.e., get max power of 190whp at 4500rpm, and maintain that power level all the way to redline (therefore, the torque would be decreasing after 4500rpm) ?

Finally, any idea of dates? I'm not a diy'er so a plug and play setup like what flyin miata sells is very attractive (ecu already tuned). I need to know what route I'm going to go for in the 2011 season depending on when your product is released (and whether or not it will be plug and play).

 

Just duplicate CoralDoc's C15-60 setup. It won't be a complete kit though.
We'll have intercoolers for all years shortly.

 

You can probably get something like that with a bov made to open at the specific psi you want. In other words the oversized SC would make lots of boost and the bov would open up to vent the extra so it doesnt overboost over your target. Centrifugal scs, not twin screws...

 

You would need to run an external wastegate on your charge piping. Size the blower to run to it's max RPM at your redline. Don't use a restrictor. Use a larger Rotrex, and then set your boost target with the wastegate. Re-route it into your intake if you want.

 

The problem is that the needed dropping torque at RPM > 4500 means the boost needs to be dropping too. An intake restrictor tends to be closer to a power limiter.

 

EBC and drop the boost target to suit? This would be very attractive for a NASA TT car. Hit your WHP limit low and ride it to redline.

 

I suppose that's possible if the blowoff valve is chosen so that its flow is infinitely adjustable.

One could also use a DBW throttle butterfly in the compressor inlet to modulate flow and thus output power.

 

Hi Emilio, I have a couple questions for you. I have a full Borla exhaust with the stock exhaust header, an EMS Hydra, 440cc injectors, high volume fuel rail, MAP sensor and a home made cold air intake with basically no restrictions (K&N air filter, no maf). I also have the mazdaspeed motor and diff mounts, two wideband O2 sensors (one for the hydra one to a seperate a/f guage). Looking at the rotrex setup it looks like it would be easy to run intake piping from my cold air box to the Rotrex intake which I like.

My questions are these; I want a stock like torque curve ( close at least) and roughly double my stock 108rwhp, more is good. Which blower would you suggest, the 15-60 or the 30-74? Is 210hp the max for the 15-60? My engine is a stock '01 (other than what I've listed and an aluminum rad, m-tuned coolant reroute and an oil cooler/filter relocate). At what point do you need an intercooler with the rotrex and does the throttle reponse suffer with an a/a intercooler

Sorry, it's a long post.

Jim

 

jimj64,

C15-60 run at full speed w/o restrictor.

 

What boost level should I expect to see and is 210hp the upper limit? I'm curious about the limit of the C15-60 in terms of future power increases, although I'm not planning any, you never know. Thanks for the quick reply.

BTW, I do not expect anyone to say "210 is exactly what you'll get" I know there are a million and one variables and no exact answers.

Jim

 

Maybe 8psi. Honestly, I don't get too wrapped up in boost numbers. Sorta like tire pressures. Just a number and not a measure of power (or grip).

C15-60 will be topped out at 210-230whp. C30 will top out 280-320whp.

 

I have to agree, but it is a useful tool for comparison and guaging other things like intercooling. Kind of like dyno's, useful and meaningful tool if used and interpreted correctly, but not the be all end all of how useful the power your making is.

Do you have an idea of what rpm the 15-60 will start making "usable" boost at? The term usable is left to interpretation.

Jim

 

http://www.rotrex.com/Renderers/Show...Range_V4.0.pdf

http://www.rotrex.com/Renderers/Show...Range_V4.0.pdf

 

What about the c30-64?