would be nice! I would be happy with 170.

I never dynoed at a real dyno, but I did not notice or measure with my G-tech any difference between 13.5:1 and 12.8:1 AFR at 7,000 rpm. My power actually dropped off below 12.8:1.

I don't know if the 197 Whp number is correct on 4X460cc/min

Thermal energy of gasoline: 124,000 btu/gal

Injectors = 4 X 0.46l/min = 1.84 l/min X 80% utilization = 1.47 l/min = 88.3 l/hour = 23.37gal/hr.

You put in 124,000 X 23.37 = 2897270 btus/hr = 1138 hp! At an 85% drivetrain efficiency, (227 at the flywheel), This implies that the engine is < 20% efficient!

Lets go from the airflow side. 4 X 0.46 X 80% = 1.47 l/min = At 740g/l this gives 1.09 kg/min or 18.2 g/s. At a 12.8:1 AFR this requires 232 g/s of air or 1.025 X 232 = 238 l/s (edit: at sea level, 70 F)
Because the rotary displaces 1.3 l /rev, this equates to 11,000 rpm at 100% VE.

I don't know if there are more complicated methods at work here, but the way I slice it, 460 cc injectors are PLENTY.

I can also say that my '86 would run 12.8 AFR up to 5,500 rpm on a single set of injectors (no staging until that point). It would also do a 14.8 quarter at 105 mph (it was not that slow/starved for air).

I was using peak and hold on the Haltech.

Try your calculations for 4 x 550 cc's.

I forget what the hp number is, but most people recommend upgrading the injectors to 720 cc after a certain whp for turbo cars. Ballpark 300 whp. What's the efficiency ratio there? (for 300 whp and 4 x 550 cc)

Nice calculator for injector sizing:
http://www.rceng.com/technical.aspx

Bear in mind that turbo fuel requirements / per horsepower are considerably higher than NA requirements.

Unless designed very carefully, a turbocharged engine is less efficient than a naturally aspirated engine.

300 whp looks like about 25% efficient with 4X550s (this is a little high for a stock turbo configuration) I would be worried with 4x550s at 300whp on boost.

throttle body, intake manifold and megasquirt arrived today!!

http://img.photobucket.com/albums/v2...B/DSC03735.jpg

http://img.photobucket.com/albums/v2...B/DSC03736.jpg

^^ Can you tell me that setup and where to buy those parts? I'm very interested in setting up an ITB setup but i want to stick with FI not carbeurators.

Still, we're talking similar efficiency numbers, or at least it sounds similar to my ear.

The person I know had to shut the car off on the dyno since the NA injectors' duty cycles were getting to high at 197 whp.

If they maxed 4 460 cc/min injectors out on the dyno, and made only 197 whp, they either had the parking brake set or were running way too rich to make peak power.

The numbers will not be that close, I really doubt that a 25% thermal efficiency can be achieved with a stock turbo and safe tune on a turbocharged rotary.

I have seen 30% (calculated) on an NA rotary.

The megasquirt can come from a variety of sources.

The manifold can come from a few places as well. Same manifold for a Weber.

The ITBs i got used, but new TWM, Tweakit and a few other places have them.

AFR was at 12.8 : 1, which is slightly richer than where I would've have put it.

Where they running peak and hold on the injectors?
What was the fuel pressure?
What was the injector duty cycle?
What timing advance and split were they running?
Did they have a bridgeport or peripheral port and scavenge a lot of air/fuel charge without burning it? (Making the Air/fuel ratio appear leaner than it really was and wasting fuel.)
I can't think of any other reasons that the injectors would be maxed out at that low of a horsepower number.

Even the online calculators (which assume a higher BSFC than a well tuned rotary has) say that 460 cc.min injectors should make 250 WHp.

Streetport, that's all i know.

I am hoping to at least get the car running before i leave for basic. When i get back i plan on building another engine for it. But i should be able to see what kind of power i can get out of a stock port engine.

Peejay just made 170 with his streetport setup on a megasquirt via Dynopaks

Well the 13B starts. Going to attempt some rought tuning but i leave in 6 days for basic so i wont be back to touch it again til September.

What ITB is that?

efi hardware Pro Race with the tapered air horns.

(be non sized down version of that pic makes a great desktop pic)


http://img.photobucket.com/albums/v2...B/DSC01189.jpg

Can RX-8's play? LOL

When I was NA I made 202-rwhp and 132 tq on a stock keg (no porting) and running the factory EMS (no tune). I had the stock intake and cat in place.

For all the crap the Renesis gets sometimes in NA form it's actually not too shabby :)

no question that their power is comparatively impressive, but i must say that i've been a bit disappointed with reliability - not of the motor, but the whole car.

How did this ever turn out for power?

anyone have current updates?

also i would like to have altitude added in. My testing will be at around 4000 ft which will show less than anyone at sea level.

just need a wideband

Only Updates I have are as follows:

216 WHp = 63% Duty cycle on 4 - 460 cc/min injectors on Peak and hold (14.16 V from alternator) giving 13.3:1 AFR. This comes from my Haltech data logging while I was on the dyno making 216 WHp. This is very comparable to online calculators.

I still think that 200 WHp is attainable for you, you have a better intake setup than I do (although mine had been heavily modified from stock). This should offset the altitude difference (I am at 800 ft).

i really need to build an engine for the car. The original 200,000 mile 6 port engine will die sometime.

It might last longer than you expect. Mine is up to 245k now and still running strong.

knowing my luck that is true, but it wouldnt hurt to get something in the works.

only 19 days til idaho. I am going to take on some changes once i get to working on the car again. Primarily going to CAS and having ignition control. Additionally, i am going to get a wideband so i can properly tune the car. otherwise its just guess work.

What kind of port work did you do?

How are you actuating your 6PI?

That manifold that you used has to flow better than the stock 6-port manifold, maybe you can get 200 WHp. I am really convinced that the biggest problem with 6-port blocks is the late intake port close and the second biggest problem is the intake manifold.

The third problem is the tiny primary ports. If you use GSL-SE end plates you can use a Y or nitrided R5 intermediate plate, but then you have to use pre-'86 rotor housings.

my current engine is 100 percent original s4 6 port. I need to build something more suitable.

You have an aftermarket intake manifold though, right? That has to help your power, there is not much worse design than the factory s4 intake for power.

yea its aftermarket

Ok, maybe I am missing something, but what makes the P-port expensive?

All you need is a set of housings, some aluminum-ceramic or Devcon and a hole-saw.

Then you can fill your side ports with iron-ceramic or Devcon and you have a P-Port.

I doubt that you would need a 2-piece Eccentric shaft, etc. for a 250 WHp build.

eh, i guess homebrew wouldnt be soo bad to try. hmm now my gears are turning. i wonder what the limit of my ITBs would be.

im thinking about buying a drill press from the local industrial surplus place, and aside from other things, that should be able to handle some p-port drilling so i might say hell with it and experiment.

rotor housings are cheap.

I want to do a semi-pp, leave the primary ports alone (they close pretty early) and fill the secondary ports, then connect a throttle plate for the two primary runners (I was going to use part of a TII manifold). Each of the peri-ports gets an ITB that feeds the port directly. A progressive throttle linkage will allow the engine to only run on the primary ports until about 30% throttle, at which time the P-ports will start to open.

I think it will work very well. If you don't try it, I intend to. I have the utmost confidence that you can do the project justice.

I had an idea for a setup where I would connect the primary and secondary ports together, and run each set to two of the ports on a four barrel throttle body, then run a pair of peripheral ports to the other two ports.

With a pair of reasonably small peripheral ports that open late to help keep overlap down, and a staged throttle linkage, it'd probably be reasonably drivable.

It's been done before. I think it was Jaytech that made a square-bore 4-barrel semi-PP intake manifold.

The trouble with the late intake close P-port is that you might as well go with a side port. All the advantage of the P-port is lost if the intake port closes after pushing 40% of the engine displacement back out the port.

I think that the progressive throttle is the answer, keep the P-port throttle plates as close to the housing as you can get them and run the primary ports normally. The primary ports will not be open after the P-port has closed, so there is no loss of charge air. If you leave the secondary ports functional, your intake charge that just came in the P-ports will leak out the secondary side ports as the compression stroke begins, negating a large part of the P-port benefit (which would be a full compression stroke allowing better torque output).

Overlap is useless under vacuum, but does not hurt that much at WOT. In fact, with a well tuned exhaust and intake, the engine will actually flow unused air from intake to exhaust during the overlap, slightly cooling the combustion chamber and increasing net thermodynamic work from the next air/fuel charge. This will increase Volumetric efficiency and torque output.

If the primary ports (with no overlap) are used for idling and cruising, and the peripheral ports kick in only when the gas is floored, the car should have good driveability. I was going to use 6-460cc/min injectors, 2 in each p-port and 1 per primary port (in the center iron). This should give a decent transition, especially if the engine was tuned on TPS.

i am going to try straight Peripheral with the side ports eliminated.

but regarding the semi-pp, i wonder how an rx8 engine would work out with the whole side exhaust thing....hmm