checking the heart rate eh? stethescope stylez. haha....those numbers arent bad at all man...i know how you drive that thing and that motor has been shredded on for what...a year and a half now right?

 

That rules. Good numbers for such a crazy port. I dont know if that knowledge would burden or bless me, but the tool would be crazy handy. How many people want you to test thier ride for them? Yikes. Youll never pay for beer again.

 

My new half bridge pulls 3-4lbs of vacume at 1100rpm. 90psi compression check no throttle I idles like ****, but hauls ***.

 

still have your car?

 

Overlap doesnt affect a rotary, however, it does a piston engine.

 

Dude, go onto howstuffworks.com and look at how a rotary works. no air is going to be drawn out of the exhaust port! and by the time the engine has completed its intake stroke, the exhaust port has been closed for a good few degrees. No less air is going to get in because of overlap, id imagine that you always have atmospheric pressure in the housing before the compression stroke begins, because the engine is moving so slow that flow characteristics do not come into play.

 

Let's look at this a different way to help you out.

A stock port engine has virtually no overlap. So, when the intake port opens, the exhaust port is closed. Provided the throttle plates are open during the test, the engine is free to suck in as much air as the sealing surfaces allow.

Now let's do a big streetport or a bridge or something and cause ourselves some overlap. When the intake port first opens now, the exhaust is still open as well. Okay, sitting aside the argument over whether or not the intake air will exit the exhaust...let's wait a few degrees until the exhaust closes. Now, look at the intake. It is still open, is it not? The timing, from this point on, is still the same as it would have been with an otherwise stock port. So from the point that the overlap stops, you're no worse off than you would have been with a stock port...which you agree should provide normal, high compression results.

So explain to me how overlap LOWERS compression. IF anything a large port might give you a hair more airflow, but it certainly could never lower it. You're not covering up or making smaller any of the ports...therefore you are not adversely affecting airflow or compression. It's common sense if you follow it to it's logical conclusion.

EDIT: for the hell of it, let's now pick back up and examine your argument that air will be drawn out the exhaust during cranking on an overlapped port setup. Why do you think this is so? There is no pressure in the chamber while the overlap is present. The rotor is sweeping away from the exhaust port, not toward it. IF anything, exhaust air is sucked into the intake charge, which would only lead to MORE than normal air being compressed. This is, in reality, exactly what happens when an overlap engine is running...thus the rough idle, because of a diluted intake charge. Once again, overlap could never cause less air to flow, only more.

 

nah....my heart couldnt bear seeing it sit here in front of my house gathering dirt and rust after it was all tuned and finished...made the choice to move my company and life to SF..and san fran is not where rx7's can stretch the road. more bums crossing the streets than potholes. My beauty is off in Virginia now, raping v8's and drawing stares. She is missed.


j

 

we have a compression check, gauge set at my school (UTI). Will this work for a rotary? I did it already but i'm not sure it was correct because we left the schrader valve in the line. But it gave me readings of 120 psi on both rotors cranking 5 to 6 times. Is this a mal-indication of my compression? Is there a special compression tester for rotaries? None of my teachers could give me a straight answer.

 

Good to see ya on the board Jason .

I remember driving a certain FD and scaring the **** out of you.....remember when we absolutely crushed that ricer celica lol!!

anyway, time for you to get back on the horse my friend, 20b for you !

Rich