10:1 comp max boost
 

hey guys I am new on the forum. I have a 1998 nb mx5 with a rotrex supercharger. Its on about 9.5 psi and makes around 220hp at the wheels. The motor I have at the moment has a 9.5 compression ratio as it is standard. I am thinking of building a 10 compression motor with forged internals and running about 10psi through it. Will a 10 compression motor be able to safely handle 10psi providing its tuned properly? thanks guys.

Sure. I'd run more boost and less compression myself. You can take the heat out of the boost.

Woh, a roterx? Post pictors now.

i will take some pics tonight and post them.

iirc, y8s is making 260rwhp on his 10:1 motor at 9.5psi.....

we need a sticky about how boost is irrelevant.

I'd say you're safe up to 250 rwhp if you have an INTERCOOLER.

otherwise, call it 225 before the intake temps are too hot to be safe. *shrug*

pics! pics pics pics!!!

A 1998? I'm guessing a '99 released in '98 then?

Overseas they released early I think

in both a 1.6 and a 1.8 IIRC?

I could be wrong, its late, I'm tired, and I don't really care to find the real answer.

yeah its an australian car so a 98 nb. 260whp sounds great. What sort of head work do you guys recommend for supercharged cars?

Yes.

I use an '03 10:1 bottom end and a tiny GT2554R running 10psi. IATs are good with an 11x11x3" FMIC. Your Rotrex puts more heat into the intake charge but the fuel you have over there has better detonation resistance.

A knock sensor and EGT with proper monitoring/management are a good idea.

No reason why you can't, as long as your engine management and tuning ability are up for the task.

my rotrex would put a lot less heat into the intake then a turbo - it does have a fmic too. and the 5th injector is just before the throttle body so that would take out whatever heat that the intercooler didn't

here is an old pic of the engine bay but its pretty much the setup:

http://filestore.redlineau.com/files...rged%20011.jpg

http://filestore.redlineau.com/files...rged%20012.jpg

that is just beautiful!!

And have you ever lined up with a new GTO for a quick race?

nope I have not really raced anything. I do a bit of mountain driving and it seems to be pretty sharp around the corners.

that thing looks sick

is that the first rotrex miata?

there's a few across the pond.

im running 10-11psi on a stock 2002 Motor with no problems. Tuning has a lot to do with how much power you can make on a given motor. For a "built" 10:1 comp. motor you should be able to make more then enough power.

BTW, its nice to know that JR wasn't blowing smoke with showing those kits. Im really curious as to what they're going to get out of them.