GtoRx7.

iTrader: (12)

Well I never said it didn't have port phased rotors There is still much to be gained on the current setup. I actually just went through the p-port manifold and streamlined it a lot. It was really crude and hacked together just to get some dyno numbers. So going back to the dyno 1 more time on friday. After that the new slide throttle intake setup will go on. The new intake is also using slide throttles mounted flush with the intake flange for the p-ports. This will put it back to the lower end torque of a street port without the added turbulence. At that point it will be beneficial to stage the opening at 6-7k. Should be pretty awesome.

M104-AMG

iTrader: (8)

Logan- are you going to bring this magnificent piece of art to DGRR ?

:-) neil

GtoRx7.

iTrader: (12)

Most definitely!

M104-AMG

iTrader: (8)

I read that the GT3 RS is a good "target". Sharkwerks & Evolution Motorsports upped the displacement to 3.9L (and compression 13.3) on 91/93 octane and now 500HP N/A (515 HP clubsport) . . .

:-) neil

http://www.evomsit.com/PR_Porsche_10...Conversion.htm

http://www.youtube.com/watch?v=XzeLcvgOVzQ

GtoRx7.

iTrader: (12)

Nice find! That porsche sounds great! Its making 457 rwhp, which a rear engine car is normally 10% loss instead of 15% for front engine cars. Puts it exactly at 500 Crank Horsepower, which is what the video claimed. Our engine is at 503-505 crank hp, on 93 octane. Looks like a stalemate!! I know they are making more torque however. Darn piston engines and their great efficiency! lol

Back to the lab!!!

Narfle

iTrader: (16)

I bet Fritz and his lime GT3 would duke it out with you given the chance.

GtoRx7.

iTrader: (12)

Fritz has a GT3? Any links or pics of it? Fritz will definitely school me in the driving department

t-von

iTrader: (8)

The longer stroke helps the pistons. I would love to see what a 16x based 3 rotor would do in torque.

Rxmfn7

iTrader: (4)

https://www.rx7club.com/race-car-tech-103/i-finally-did-bought-dream-car-943051/

Liborek

Stroke has nothing to do with torque output or efficiency. Torque is solely based on displacement and BMEP. BMEP is influenced by VE% and combustion efficiency, mainly by how efficient is engine in terms of air consumption.

On stroke note, when you increase stroke, for same displacement you have to decrease bore and hence an area on witch pressure applies and vica versa.

Why is rotary so inefficient is questionable. Vast area to volume ratio is one possibility but I´ve been lately reading work of Sir Harry Ricardo "The High-Speed Internal Combustion Engine", and everything indicates, that surface/volume ratio isn´t such big factor as many are proposing.

So it probably goes down to fuel distribution and flame propagation...

t-von

iTrader: (8)

How could it not when it gives you more leverage? I know that the longer stroke will increase displacement but it also gives more leverage on the power stroke. Without all the technical stuff, I've always seen torque on a piston engines as increasing with it's longer stroke (especially with Diesels). I notice this more in the lower rpm ranges. The Dodge Cummings for instance. The older engine was a 6.0L but had a really long stoke and made 600LBS at 1,500rpms. I know it's turbo but still, that's a lot of torque. Longer stroke means lower rpm red line (something else I noticed). Another example is if you had a 1 speed bicycle and you shortened the pedal arms (bringing them closer to center), it would be more difficult to pedal because you would have less leverage. Same principle as having a breaker bar on the end of the 3/4" drive to break the big flywheel nut loose. Your never gonna break that loose with all your efforts placed near the nut. Your forgetting about the mechanical advantage at it's foundation. The rotor lobes on a rotary e-shaft are very close to the center of rotation. Not so on a piston which are further away! The new 16x has it's lobes further away from center and is suppose to make a lot more torque down low with it's longer stroke. Mazda will even tell you this! Time will tell when we start seeing a power graph of that engine.

TRWeiss1

iTrader: (20)

lol wut?! Are you forgetting about simple physics here? Last time I checked, torque = amount of force applied x distance from the center of rotation at which it's exerted. Given an equal amount of force on the piston, a longer stroke will ALWAYS generate more torque because you're essentially increasing the distance from the center of rotation at which the force is applied.

End of discussion and you can close the book on that one. :P

tvon, right on regarding torque and the rotary. I've always thought the same exact thing. The lobes on an e-shaft are very close to the center of rotation, hence the lower torque.

Liborek

But the amount of force is different

We are dealing here with pressure, you have to apply it to area(bore) to become force. And as I said, on given displacement as you increase one parameter, you have to decrease other one and vica versa

Also, you can´t do such simplification, force has to be perpendicular to arm from center of rotation and this happens at only one moment

If it was such easy, we would build engines with ridiculous ratio between bore and stroke and achieving huge torque, right?

Liborek

Well, reason why longer stroke engines are giving more torque in the low-end is simple, again it has nothing to do with leverage, but with mean piston speed and its huge influence on volumetric efficiency in given RPMs.

Turbo diesels and their torque curve has everything to do with fact that its turbocharged with very restrictive turbine which is able to build boost in very low-end and tapering down with revs due to same thing....

Narfle

iTrader: (16)

While leverage means nothing without the combustion force, it is blatantly untrue to assert that stroke length has nothing to do with torque production.

Narfle

iTrader: (16)

Haha, volumetric efficiency doesn't break that flywheel nut loose.

t-von

iTrader: (8)

I completely agree. It's a combination of both. You want the higher VE to create more air inside the combustion chamber so when ignited, you have more working force as a result. I mean the working force (whether it be combustion inside an engine or someones leg pushing down on a bicycle pedal) will have more force if that force is further away from the center of rotation. That's just the simple laws of physics! More boost pressure just gives you more working force. Stronger legs will do the same. With my 3 dimensional mindset, too me that's what I see.

Liborek

I´m not proposing such thing, stroke aka leverage is essential to create torque ie rotational force, but examples with bikes or breaker bar aren´t applicable in internal combustion engine. With given displacement, when we increase stroke, we have to decrease bore which decreases AREA on which PRESSURE applies, hence the force is not same. We increased leverage, but decreased force and again, it is applicable in other way.

Trots*88TII-AE*

iTrader: (11)

No comment. This argument has already gone on too far, we need to stop bullshitting up the OP's quality thread.

Narfle

iTrader: (16)

Edit: How about some spring time pictures and video

Rawbz08

iTrader: (7)

what would a round about cost be for itb setup for 13b semi pport intake setup. or to modify the lim to accept semi pport

GtoRx7.

iTrader: (12)

Its cool guys I am never one to miss a chance to learn more information. I did go back to the dyno today, and got to stretch the FD's legs a little. Did all types of video, and
tested 4 setups individually. Here is a overview, going off memory. Dyno charts and vids coming next!


-First I streamlined the semi p-port manifold some, just making the best of what was there. Did some pulls, and it did indeed help and made 434rwhp. Biggest surprise is 250 rwtq! excellent.

-Next I swapped in race plugs, due to so many members telling me that 10hp or more can be gained. I was a doubting tomas, but bought some anyway to test back to back. Result? 436rwhp. 2 horsepower for $190??? Yeah looks like this goes into the "busted" category.

-Then we swapped just upper intake manifolds, and ran the stock intake with semi p-ports. Shocking result #1 of the day, it make 420rwhp. Looks like semi p-ports are totally amazing in flow.

-Then I removed the gasket from the lower intake, and swapped in a stock one without semi p-port holes. This blocks off the semi p-ports at the flange. Then did some STREETPORT only pulls.

- Shocking result #2 of the day, the stock intake/streetport made 350rwhp!! Amazing!!!
Last time I tested the stock intake the electromotive software had a glitch which was not sparking leading #3. So Leading ignition missing on one rotor makes for a 28rwhp loss. In case anyone wondered lol

- Lastly we then swapped on the sheet metal intake/ streetport only. Kinda disappointing result, hit 355rwhp. It did lean out a bunch, and didnt have time to re-tune. I think it would have made 360-365. Only a 10-15 hp gain. But not bad!

t-von

iTrader: (8)

Great testing Logan! Just goes to show what some well built headers will do for NA rotarys with stock intakes. So how did the bottom end look when compared with the stock upper? I'm not that surprised at what your stock mani did when you compare it to your 13b Re set-up. Both uppers are virtually the same. Your making about 115 rwhp per rotor. It adds up!

Slevin_FD

iTrader: (26)

Good stuff Logan. Now I just need to come up there and drink you into telling me your secrets. lol until then MOAR Video!!!!

GtoRx7.

iTrader: (12)

We will be selling modified lower intakes with semi p-port manifold attached with ITB's. Cost is projected at $650 or so for a 13b.