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Naturally Aspirated Performance ForumDiscussion of naturally-aspirated rotary performance. No Power Adders, only pure rotary power!
From the "12A" to the "RENESIS" and beyond.
Well I bought the engine from a guy that lives over in NJ and had it shipped on a pallet to my place. Runs pretty strong with the S5 T2 intake so I can't wait to see what she does with a more optimized collected exhaust setup (currently running RB true dual setup since it was what I had on hand) and with ITBs.
Racing Beat collected header works pretty well for the money and you can get it shipped to your door pretty quickly. There is certainly the possibility to make more power with a custom exhaust but would likely take a couple different iterations to get right since you would be searching for the correct primary lengths that make the most power with your specific setup. Then on top of that if you decide to make any changes to intake or engine, which it sounds like you are, your exhaust would have to be redone to be optimized for the new setup...
Bored at work post... looking at the RB Dellorto upper manifolds to bolt to the stock 6-port lowers, I wonder if something like that to use GSXR throttle bodies might be worth making, or if the LIMs are sufficiently terrible to not be worth the bother.
I think the intake length becomes too long at that point. Plus you are making the air do a 180 deg turn before going into the chamber. Keeping the turns to a minimum is a must IMO. Resonance tuned length of around 11 to 14" from face of the keg to the end of the ITB trumpet seems ideal in my calculations. Keep the intake runners really short and get different length trumpets and find out which length the engine likes on the dyno.
11-14 inches? Jeez, what are you trying to do? From an old paper Mazda did, they were looking at 14" to get a torque peak around 8500rpm.
(I have my Lake Cities style design for that)
I figure that the stock LIM and something wrapping around or, yes, sticking vertical might be in a runner length realm for someone doing a reasonable street car.
Do you know the runner diameter of the N/A lower intake? I was looking to keep the same 46mm size from the 'busa TBs all the way down to the flange and do the final port matching at the flange. This is for a dedicated track car. I just picked up a 10ae so fun and reasonable street car is covered.
Not trying to thread jack just some idea sharing since ITBs were part of the original post. Does anyone remember the name of that japanese site that has a lot of turbo cars converted to n/a with pics and dyno numbers of setups? I seem to remember seeing some make around 270 with intakes that curve up about 140 degrees or so
Some really interesting setups in there. Actually looks like they make their own cast manifold that turns about 100 degrees. Sometimes they have what looks like a RB lower 90 deg section and they add their own upper section that turns it a bit more but not full 180. Seems intake lengths to keg look about like 14-16 inches and up depending on the car. They claim 270 metric HP on a bridgeport n/a and the torque peak looks to be around 6700 RPM
They claim 270 metric HP on a bridgeport n/a and the torque peak looks to be around 6700 RPM
That sounds a bit tough. 6700 rpm isn't much! 270 hp is a lot.
JPR completed the porting! I get to pick it up on Monday.
Most of the parts will be here by the next weekend, except a flywheel and Fitech. Buying Fitech after the motor is in the car. I am planning to get the motor in the car by March
So I ended up ditching the 'busa ITB idea in favor of 4x Ducati 749/999 TBs. They measure about 52mm at the bottom face so could be a really good fit for a ported rotary... Waiting until spring to start the manifold fab and Megasquirt project although these 50 degree days are starting to tempt me back in the garage
Took a while to get stuff done! Motor was ported by JPR, half bridge, staying conservative.
Exhaust ports are just T2 sleeves, no porting there.
Motor is built but waiting on the dial gauge to setup end play.
Exhaust will be RB with some cheap Jones mufflers. If I melt/destroy the mufflers I will have to figure out a better solution. I don't want to be too loud.
Still got a few things I have to figure out.
1. Timing and Dizzy. How to set up the dizzy with stock coils. I know the 12a setup with msd, so this should be similar. I have to look this up.
Just found out tonite that my used dizzy has 1 ignitor missing!
2. Heater hoses. No clue where these will go! I won't have AC but I do need Heat for winter.
3. How to wire the car. I want to keep the body wiring and as much functionality of the stock gauges as I can, atleast for now. We will see how this plays out.
01-25-17, 09:52 AM
