Is there any information on the website showing the timing of the
 intake
 and exhaust port relative to eshaft rotation?  I am specifically
 interested
 in the overlap and the e-shaft angle at which the apex seal clears the
 exhaust port.  Inspired by your 555 system, I have designed a simple
 digital
 converter to convert MAP to pulse width for controlling the
 injectors.  We
 know that the volumetric efficiency of the p-port at 6000rpm is 120%.
 I am
 wondering how much of that 120% is represented by intake air passing
 through
 the chamber and out the exhaust during overlap.  If this occurs at
 all, it
 would improve efficiency to minimize the amount of fuel in the
 bypassed air,
 suggesting that the injectors should be opened after the exhaust is at
 least
 partially closed


 Victor Roberts


 I don't have the numbers for the timing but it is exactly the
 same as the Le Mans 4 rotor.

 http://www.rotaryeng.net/**Mazda_R26B_US.pdf<http://www.rotaryeng.net/Mazda_R26B_US.pdf
 http://www.rotaryeng.net/**Welded-steel-p-port.html<http://www.rotaryeng.net/Welded-steel-p-port.html

 The numbers can be derived from the scale dwg in this last link.

 The exhaust and intake P-ports in a rotary never really close.
 In that regard it is more like a turbo jet.
 What air does not go in one chamber goes in the next.
 In a tuned rotary engine however the max pressure in
 any given (One of 3) compression chamber depends on the RPM,
 pipe length and pipe diameter.


http://www.rotaryeng.net/**Mazda-p-port-press-wave-**enhanced.jpg<http://www.rotaryeng.net/Mazda-p-port-press-wave-enhanced.jpg

 The best place to measure this pressure is the apex oil injector
 holes just above the p-port intake. Of course one is not using
 these holes for oil injection. One mixes the apex oil with the fuel.

 I am coming back to the 555 system and adding a single chip computer
 that
 has the sole job of adjusting the mixture using a USB port and
 storing the trim data in a spread sheet format. The program becomes
 extremely
 simple and easy to comprehend. Merely a look up table in the single
 chipper.

 Henry Nee came up with this great idea and people can email and
 share
 trim
 tables. Any number of trim tables can be stored in one's PC. It also
 makes
 editing the trim table simple as you do it in your PC using a spread
 sheet
 program. This should greatly speed the tuning of your engine and
 similar
 installations can use the same trim table. We can put them on the
 web
 site
 for rapid download. Parameters affecting the trim are type or
 drag of
 the airplane, diameter and pitch of the prop, intake pipe length and
 gear
 ratio used. Assuming all are using a p-port.

 Paul Lamar

 Victor,   I have seen the port timing numbers in the Kenji Yamaguchi
 (SP?)
 papers.  I think there is a link on Paul's  site  and possibly on
 Craigs
 Rotary List site also.

 george grimes

 http://www.turborx7.com/**porttiming.htm<http://www.turborx7.com/porttiming.htm

 cbeazley

 From Mark Warner's book Street Rotary, page 34, here's a port timing
 chart of various Mazda models.  Here's a link to the book:


http://www.amazon.com/Street-**Rotary-HP1549-Horsepower-**Reliability/dp/<http://www.amazon.com/Street-Rotary-HP1549-Horsepower-Reliability/dp/
 1557885494/ref=sr_1_1?s=books&****ie=UTF8&qid=1321457929&sr=1-**1


 Tom Sash

 Much of this is useless info as it makes no sense to port a side
 port engine for aircraft use. If you need to take the engine apart
 to port it you might as well P-port it. The p-port intake manifold and
 slide
 throttle are easier and cheaper  to make than a side port manifold.
 You wind up with 25% more power and a better BSFC.

 Most of the road racers need it because p-ports are outlawed due to the
 rotaries over helming domination of most road racing classes.

 Only in the Rolex GT class are RX8 3 rotor p-ports allowed and then they
 suffer from extra ballast and an enforced red line 500 RPM below the
 street
 engine.

 Paul Lamar


 These numbers for the Mazda P-port are bogus.
 As Paul has pointed out, there is an overlap of intake timing between
 adjacent rotor faces.

 When the apex seal is in the center of the port, two chambers are open
 to the intake. From this position, after 360 degrees of shaft rotation
 the rotor face which was just beginning intake before the rotation would
 still be half open to intake after the rotation. The intake period
 exceeds 360 degrees of eshaft rotation.
 Reference these numbers to after TDC and it becomes apparent they cannot
 be true.

 The intake opening at 86 BTDC is 274 degrees of e-shaft rotation
 After TDC.
 The intake close of 75 ABDC is 255 degrees After TDC.
 This gives us 19 degrees of shaft rotation where neither is open.
 For the exhaust, opening at 73 BBDC is 107 After TDC, and closing at 65
 after TDC - 42 degrees of shaft rotation when no exhaust occurs.

 It appears to me that the interior circumference of the rotor housing
 is about 27 inches; so 360 degrees of shaft rotation is 9 inches. A
 two-inch port opening then requires 80 degrees of shaft rotation to
 transit, so the trailing port opening occurs 80 degrees ahead of the
 leading port closing. The intake period including overlap is about 440
 degrees of shaft rotation.
 The exhaust port appears to be half the size of the intake, so 400
 degrees of shaft rotation from opening to closing.

 Tell me where I am wrong.

 Victor Roberts

 The intake period is 270 degrees of e-shaft rotation as are all other
 strokes. In a p-port there is a depression in the rotor face that
 connects the intake port with the exhaust port. Surprisingly the
 pressure in the intake is higher than the pressure in the exhaust.
 Therefor air flow, if any, goes from intake to exhaust in theory.
 However air has mass, friction, adhesion and inertia. So what
 goes where and how much is arguable.

 Here is a Racing Beat 3 rotor P-port turbo making 900 HP as I recall.
 Some of the end housing are aluminum.
 Note the size of the turbo charger :) One would think the injectors,
 being on the plenum side of the long intake runners, would lose
 fuel to the exhaust. Jim Medere told me that was not the case.
 In fact the BSFC was slightly better with the injectors at the start
 of the runners. I can't wait to see what happens when Dave Lemon
 builds a welded p-port with a slide throttle RX8 engine. Should be
 around 600 HP or more instead of only 420 HP :)

 As I recall the 3rd gen RX7 stock body land speed record at 268 MPH was
 set with a 3 rotor, 3 turbo side port engine making only about 750 HP.
 It had an ice water inter-cooler as I recall.

 BTW a picture taken from my C182 made the centerfold of Pop Sci
 mag the year of the flood at Bonneville. That was the first year the
 recording holding R.B. 3rd gen 3 rotor RX7 showed up.

 http://www.youtube.com/user/PaulLamar2#p/u/11/JUf_aWVVl7o

 With our man on here Csaba  Csere narrating no less.
 I got my 2 cents in at the end.

 Paul Lamar


 I have to wonder about the concern everyone has been showing about
 overlap.
 There is considerable overlap in any piston engine. The exhaust and
 intake
 valves are both open on even a low output piston engine. There is even
 more
 overlap in a high output engine. I haven't timed any cams lately but iirc
 the cams have about 30 degrees of overlap. Due to the velocity and
 mass of
 the intake charge some will often flow out the exhaust. Since the rotary
 doesn't have valves in the way timing is very important, but a lot of the
 overlap events are similar.
 Bill Jepson


My concern was in the volume of air that passed from the intake through
the chamber and out the exhaust, and the amount of fuel in that flow. It
appeared to me that if the injector timing could be manipulated so that
at cruise power the air passing through to the exhaust carried the least
possible amount of fuel, better efficiency would result.
It may be that the volume lost is inconsequential, or that the timing
cannot improve the loss - but since lean cruise fuel flow is less than
half max power flow and therefore injectors are on less than half the
time, it seems reasonable that some injection timings will be better
than others.
One reason direct injection engines can get better fuel mileage is that
they lose no fuel out the exhaust during valve overlap.  It is also one
reason that port injection engines can get better mileage than those
with throttle -body injection.
I ask the group's forgiveness for my intrusions - I know I have a gift
for causing unintentional irritation.

Victor Roberts


You have a valid point there Victor. When the fuel is injected relative to
top dead center could be important.

So far we have no control over that as Tracy does not publish the source
code of his system. We think he injects fuel once a rev. I'll find out
as soon as I get my engine instrumented with a data aq system.

Paul Lamar


Easy to check the behavior of Tracy's system - scope one of the injectors.

If he injects once per rev (which I think he must), and you want to change
the timing of the injection, just put in a delay to the system trigger
Tracy's computer.  It's kind of a glue-on kludge solution, and the best
delay will vary with RPM, but it should still work fine.


Regards,

Matt-