N/A 20b build

[aaron_bc]

Oh... N/M then. Lol...

[project86]

i wish i was from Hawaii

[aaron_bc]

Vancouver's better anyway

[Prodigy]

I'll throw my vote vans way... As it's 'local' compared to the islands...


I'm hoping to make it out this fall for a couple days... Enjoy the city and such...

Maybe take a quick dip into the Seattle... See if their are any meets, on either side of the border....


J.

[gmonsen]

Sounds like a good general plan to me. I would suggest you go with a 90mm throttle body instead of ITB's with a large street port. The street port runs out of steam at around 7500 rpm. You are totally constrained by the stock throttle body. There are plenty of 90mm throttle bodies you can mate to the intake. You should be able to make close to 350 with that. If you want to go higher, you really want to go pport (or semi pport)and ITB's.

Gordon

[GtoRx7]

Late to the thread, but figured I would throw in some info. I have been doing 20b n/a R+D for over 6 years, and over the past 6 months its really coming together. This is mostly to put a bunch of facts on the board. And to produce some of the most powerful n/a 20b's in the world for my customers (Christopher is a big one that comes to mind!)

Proven 313 rwhp 20b spec sheet-

20b with our circuit port on intake and exhaust
USED not new 9.7:1 rotors
Balanced assembly
Stock 20b stationary gears and bearings (identical to fd bearings)
110psi regulator
new stock oil pump
Our stainless 20b equal length header
Stock intake manifold, shortened stock lower manifold
Standalone of your choice
3" exhaust from header back
8000rpm
Stock apex seals
stock used rotor housings

Thats it, good to go. If you want 350rwhp+ we have done this as well, and I can help guide you in the right direction from facts and actual results.

[NoDOHC]

I believe the above, as I did 216 WHp (Mustang) with 8.2:1 polished s4 turbo rotors, stock s4 rotating assembly (not balanced), stock intake manifold and very mild porting. An equivalently built 20B should make 320ish WHp.

[GtoRx7]

Nice work, can you link me to the dyno chart?

[NoDOHC]

I fixed the rich spot later, but I had the AFR trace off for the next run that I got a picture of.

Although the curves do not line up, the rich spot made the dip in the torque curve. I wish I had a picture of the afr on a run with a 13.3 afr throughout, but once it was good, I was fooling with trailing split and had the afr trace turned off.

Edit:

I should also post here that target AFR was 13.3:1 (optimal power). Ignition timing was fixed at 38degrees BTDC above 3000 rpm.

I was initially running from 3000 rpm, but I had to wait too long between runs for engine cooldown, so I started at 5000 instead to minimize the engine heating. I revved to 9,000 once (182 WHp at 9,0000 rpm) I think I was ignition limited, as my peak VE was reached at 7,700 rpm and my power had long since started to fall off at that point.

BSFC was right around 0.42 lb/Hp.hr until 6,800 rpm, where it started to increase to 0.54 lb/Hp.hr at 9,000 rpm (which also indicates an ignition problem).

Interestingly enough, this engine only barely eaked above 100% VE (I saw 102% at 7,700). Rotary engines have a lot of potential.