GtoRx7

iTrader: (5)

When you pull in the split timing, and make the trailing fire closer, or even exactly the same time as leading, it usually results in more power. On the dyno I would see a 3ft-lbs+ gain from 0 split vs 6-10 split. Not tons of power, but still a good amount.

Hyper4mance2k

iTrader: (40)

with the stock dizzy you can't get less than 8* of split.

GtoRx7

iTrader: (5)

Nah, you just have to make the slots larger. I ran 2-3* split on my dizzy for quite a long time.

dj55b

iTrader: (2)

now is that zero split all the way or just at WOT? also how does this affect fuel economy if in anyway?

GtoRx7

iTrader: (5)

There are a few different ways to do some tricks on the distributer. You can run near zero split, and then only hook up the leading for vac advance, so under cruising 10* split will still occur. As for me, I ran a solid zero split past 2000 rpms, and have not noticed a fuel economy difference vs when it was 6-12* split.

dj55b

iTrader: (2)

I have a standalone ... so i can program it to run what ever. There's no way it would harm anything running just 0 split all the way though right?

theory

iTrader: (5)

So I just read all 11 pages again. Does anyone have any references/sites that clearly explain different porting types (intake/exhaust) and how they open/close later then stock, I'm trying to understand and follow the technical conversation here but I'm not sure how/why port opening/closing affects things...

I'm on the fence for my next build, and if I can figure out some of these things I might stay on the NA side of the fence for a while longer.

Shainiac

iTrader: (7)

Here's a pretty visual and explanitory site that shows the difference between many different porting styles.
http://www.rotaryengineillustrated.c...ts-intake.html

diabolical1

iTrader: (3)

hey theory,

feel free to PM questions to me. i don't mind clearing up anything that that site doesn't help you with.

GtoRx7

iTrader: (5)

After over 11k miles of 5 and 0 split, hundreds of dyno pulls to over 8600rpms, dead cold winters and hot summers, many drag races, my engine still seems perfectly happy with it Lol.

dj55b

iTrader: (2)

cool ... i'll try that out then. So you have 5 degree split below 2000 rpm? Also how's the color of your spark plugs?

peejay

Mine definitely makes more power than my 6-port did, everywhere on the band. (Same exhaust system and everything - the 4 port wanted more fuel EVERYWHERE. Including idle and cruise )

Then again my 6-port was a GSL-SE with its soda straw intake manifold. The 4 port doesn't idle or cruise as nicely, but the intake ports close at about 70ATDC primary and secondary so that is probably understandable. The better low end kinda shocked me.

The aux ports' shafts take up a huge amount of cross section by themselves, and disturb the flow. And remember, ALL air going to the end housings needs to go past those sleeves...

Mine didn't have those. Mine also felt more powerful than a friend's S5 block with working sleeves and a 48mm Dell'orto...

GtoRx7

iTrader: (5)

They always are a very very light tan color. Correct 5 split below 2k, and 12 split only on idle.

This is my exact thoughts on the 6 vs 4 port. A long time ago I built a 6 port, ported the primaries and secondaries, used devcon to smooth the 5th and 6th port flow into the housing, removed the sleeves and rods, ported the shaft holders....etc etc. And it felt fun. Then I pulled the engine, slapped on a ported front and rear iron from a TII, and put on the TII intake. Took it for a spin and **** MY PANTS! the 6 port was ball-less in comparison. Ever since then I only mess with the 4 ports. haha

peejay

Yeah, thanks for setting me right, it's 4 port all the way from now on!

dj55b

iTrader: (2)

good thing you said that about the idle, because i went and set out on my car everything below 2k including idle was at 5 split and the rest at 0 and the idle was kidda crappy, but besides that the car definatly picks up nicer and might keep it like so. I'm sure it'll have more gas waste out the exhaust, but what ever, that the guy behind me's problem.

twinkletoes

iTrader: (17)

What you guys think a setup like this could make at the wheels?

13b gsl-se rotarting assembly and housings.
12a irons with RB streetport
48 ida
2.5" exhaust

Hyper4mance2k

iTrader: (40)

I know it's not the highest, but here are my results thus far. I changed my exhaust and here are the results.

Here is the thread about it:
https://www.rx7club.com/1st-generation-specific-1979-1985-18/racing-beat-exhaust-dyno-compairisons-823229/

twinkletoes

iTrader: (17)

Very nice man . I'm thinking when I get the money and it comes time when I want more power that I might half bridge the motor. I'm not sure, cause its not to streetable, plus gas mileage and reliability. I just want to spank on STI's and all n/a.

jthompson02

Anyone wanna guesstimate my power ?

S5 N/A Engine with stock ports and injectors (rtek coming soon)

Header to 3' cat delete pipe to 3.5' muffler
All block off plates installed
E-Fan
VDI removed
Butterflies removed
Round Filter

Pretty much a barebone engine

TeamRX8

iTrader: (2)

Accessport beta tester with an emissions legal Renesis back in 2007, engine was factory stock from throttle body inlet to exhaust port exit

http://www.rx8club.com/showpost.php?...&postcount=414

GSLSE-YA

I know a few guys running SCCA in EP cars have made 267hp at the flywheel from a streetported 6port motor. I think it was a 48 or 51 carb, not sure what it was choked down to.

dr. wombat

let you know when its running.
4 port 13b,(rx4 into FB chassis)
steel sleeved mega streetport.

Haraise

So is the best motor combo:

S5 NA doritos
91-95 Cosmo housings
12A middle plate

?

I'm trying to pull all the information from other threads and these pages, but I haven't seen any "this is the best combo" statements.

Shainiac

iTrader: (7)

^ You'd have a hard time running modern 13B housings with 12A irons. Neither of them have coolant seal grooves.

peejay

I am not convinced that a 12A center housing is of any benefit without use of a flat syle sidedraft manifold.

And of course you'd have to be very friendly with a machinist to modify the rotor housings to accept coolant seals on their "inboard" sides.