kirkosaki

Honestly I was giddy driving it on the first test drive, haha
My floats are around 5 mm with the gasket on.. I might re-adjust them again. In the rotary eng. manual there's a "note" saying this is done without the gasket. So 5mm from the carb to the float.. I dunno.
I'm sure mine is find as is.

Car is stock ported.
1984 GS, 12A, approx. 80k on motor
Racing beat mild steet exhaust manifold into 2.5" stainless tubing, pre-silencer into a S.S. power pulse extreme exhaust.

I'll go another degree to 4 degrees on leading and see how it works.
But as of now it pulls hard all the way from around 3k to 7k.

Buggy

iTrader: (8)

Sounds like you are on the right track. If your floats are not set correctly you will have flooding or starvation issues. If it's running good I'd just leave it. Drive it around and get a feel for how it works. Pay attention to any issues you feel and just slowly work the bugs out. Mine pulls hard right to 9k but it's also half bridge ported with dlidfis ignition.

kirkosaki

That engine must be a beast. Mine is loud but sounds amazing. That open intake sound

Yeah.I'm @ 4 degrees advanced now.
Seems good. Could go to 5 degrees I guess.. but it idles and runs good right now.
I'd like to upgrade the ignition system. Going for a limited slip and rear disks next. I got a donor car (GSL), fully loaded.

Did you port the motor yourself or?

Buggy

iTrader: (8)

Things have slowed down a bit at work so I'm hoping to get my car on the dyno next week and play with it. That's the only real way to see if changing timing is getting you any gains. If you are happy with it, I'd just leave it alone. I built my engine and did all the porting. Has S5 Na rotors, rx8 eshaft, Stat gears, and bearings, all balanced, racing beat aluminum flywheel. It's a bit of a monster lol.

kirkosaki

Nice. I got a auto rear counter weight. I want to get a LW flywheel eventually.

I have another question about the secondaries. I noticed there's no progression holes to feed fuel into the barrels when they are slightly opened. Is this normal for these carbs? I do not see the little hole for the progression circuit and I do notice a bit of lag when putting my foot hard on the accelerator when the secondaries open up.

Buggy

iTrader: (8)

I'd have to look at the carb breakdown diagram, but usually the secondary side doesn't have progression holes. I have the same issue with mine and it's accelerator pump circuit related. I think I need bigger jets on the accelerator pump. I already have 70's though which are the biggest ones pierce manifolds sell. I was just going to drill them out bigger with my numbered drills. I did the same on the 48 idf I used to have on this engine. There is also suppose to be and accelerator pump exhaust valve somewhere on these carbs, but I have yet to find it. Putting a smaller exhaust valve in will increase the amount of fuel going through the accelerator pump as well.

kirkosaki

Buggy.
I picked up some .07 accelerator pump jets. I'll drill them out a little see what that does. But I still think it's the lack of the progression circuit on the secondaries that's causing the hiccup. Car is stored now in the garage. I'll take the carbs off and inspect/clean them again..

Buggy

iTrader: (8)

It's the sudden blast of air from the throttle opening quickly that's causing that lean hiccup. Progression holes wouldn't solve that as there is little vacuum at that point to pull the fuel from them. It's the accelerator pump circuits job to shoot fuel in to correct that lean condition until the main circuit starts flowing fuel.

kirkosaki

Oh okay! Well I'll see what those new pump jet nozzles do.. they might increase flow a little but I doubt they'll help. Like you said the return circuit to the float bowl needs to be smaller to increase flow.

Buggy

iTrader: (8)

The car came out of storage and went directly to the dyno at work. First pass made 182 rwhp. With some jet changes and other small things it made 203 rwhp. This setup works very nice!

kirkosaki

Impressive numbers!

Care to share what jets and air bleeds, etc. you are using on the weber's?

I Have a chance to pick up a street ported 13B. Never been installed in a car. Asking 3500 for it.. But my 12A is running strong and I also have another 12A in storage. I want to get it but don't know if it's worth it. I like having the stock 12A for now. My car is running great btw! My battery is dead so I got a Odyssey PC680 and am relocating it behind the passenger. It better last for years to come :P

Buggy

iTrader: (8)

Off hand I don't remember what size jets I settled on. I'd have to pull them and see. It's still pretty much set up the way it came from rotary engineering just with bigger jets. With some bigger venturis in the primaries and some other little tweaks it would probably make a bit more power. My turbo fc has taken over my spare time this year.

rotarygod

iTrader: (1)

Your power curve is beautiful. Nice and smooth with flat torque. 203 seems a bit low for a bridgeport but I don't know how large your bridge is so maybe it is, maybe it isn't. For a street car it would be nice to see that power peak a little lower, say 6500 rpm or so. Total peak power would settle a bit lower but you'd have far more usable power which would be faster. Right now it appears to peak at 8300-8400. A stock transmission isn't in it's best range up there. Adding some intake length somehow could help but I don't know how you'd do it with that setup. Regardless it looks very nice and I'm sure it drives very well.

Buggy

iTrader: (8)

It's only a half bridge done using racing beat's template and the exhaust is only ported slightly which is where the real restriction is I'm sure. The goal for the car was to have something mean that I could drive on the street and not make myself go insane with horrible drivability. The car still idles at 900 rpm. The car still has the factory 4 speed trans and a gsl se rear diff. The combo works good just wish I had an overdrive gear. 5 speed swap is in the works just have to figure out which one I want to use. I have no issues using the power band in the car. I let it sing at 9k all the time lol.

rotarygod

iTrader: (1)

The exhaust size actually isn't a restriction. It's a misconception that the exhaust needs to be large. A larger exhaust port does affect power a bit but what it really does is move the max usable rpm up. You can actually go quite large on the intake side with very little on the exhaust side and get nice gains in the average power band. Rick Engman was showing me the ports on the 4 rotor engine in the 767 and was talking about the effect each side has. The exhaust ports in that race engine are only ever so slightly larger than stock. They are slightly smaller than the exhaust street port template from Racing Beat. That engine is shifted at 8500.

Buggy

iTrader: (8)

That's interesting. My personal goal for the car was 200 rwhp so I achieved that. Not really sure what I'm going to do next with it. I'll probably just drive it and enjoy it the way it is.

kirkosaki

I've realized I didn't really need those accelerator pump jets after all. Waste of money really. The oem ones are fine as is.

Buggy, did you have your rotors balanced? You said they're from an S4. I'd like to half bridge port the spare 12A I got some day. Sounds like a great combo with the dual weber's.

Here's a semi recent pic of my engine bay set up

Buggy

iTrader: (8)

I have S5 na rotors and yes I had the whole rotating assembly balanced. A large street port would probably yield you good power and have better drivability than the half bridge. Unless you want the brap brap of a bridgy.

kirkosaki

Buggy, Do you have any videos of your car idling and revving a little? I wanna hear how it sounds with the Weber's. Would it Brab Brab with the weber's though? cause the secondaries aren't being used during idle or under low throttle speeds.

Buggy

iTrader: (8)

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Buggy

iTrader: (8)

Sorry it took so long to get a video up. That's an old video I made with my phone when I was first tuning it. There are videos from when it was on the dyno on Facebook. I can't seem to figure out how to link it here from my phone. Just search 4 Wheels Performance and go through the videos. My car is in there.