zkeller

iTrader: (47)

I recently bought an FB with the Racing Beat intake/carb, stock port 12A setup.

Can anyone confirm what size power valve and jets Racing Beat uses? I took the carb apart to freshen it up and it appears that the jets were changed and I assume that someone also changed the power valve.

The power valve that is in there is a 9.5 and the jets are #60.

wankel=awesome

RB installed PV is an 8.5, and main jet is a 49.

Secondary side should be a #69 jet "plate".

Secondary Vac. Diaphragm spring should be the Yellow spring.

Pump cam should be the White cam.

Pump nozzle should be a 31 or 35. (They sometimes bore the 31's to 35.)

The idle mixture screws have an uneven adjustment from the auto chokes vac source, accounts for about half a turn on the choke side of the carb.

My guess is it runs pig rich for you atm, and I didnt include air bleed sizing here, because nobody should have been able to change those :p

Also, the Rb carb runs pretty poorly at their selected jetting IMO. Too lean on part throttle, making DD'ing irritating with all the surging.

Try a 55-58 with no power valve, was my best combo. Gas mileage takes a hit, but the engine is happy...
Happy tuning!

zkeller

iTrader: (47)

Thanks for the info. Actually it was tailing off up high. I put the wideband on it and am seeing high 14's above 5k RPM. Fuel pressure was set at 4.5, I need to bump that up to 6PSI.

wankel=awesome

Indicates too small a fuel pump... carb jetted up at an attempt to compensate...

project7s

iTrader: (5)

Sorry to high jack your thread but I agree stock rb jets suck, in fact I complained to rb and they sent me free jets for it, currently I have 56s in it with the stock power valve. One problem I'm having is sometimes the idle will float for a sec after I come to a stop. And some times it will just cut off when I'm coming to a stop or sometimes when I push the clutch in to change gears. The car has a rb aluminum flywheel so the rpm drops pretty fast when you push the clutch but it shouldn't drop the 0? Any ideas? I'm wondering if its carb or ignition related.

wankel=awesome

with a 56, youre good to remove the power valve....

Sorry for the late reply, but I had similar issues running a 58 main jet+8.5 power valve. When the engine was loaded in gear it was simply too rich, and with little load it was too lean. I removed the power valve and told RB what I thought of them for not properly tuning the PVR (power valve restrictions) for that the engine actually needed.

Their response was it shouldnt need the power valve at all at cruise, but ive installed many and built so many of my own, and they most certainly run on that circuit while cruising.

Try removing your power valve and then seeing where you are with a 56, itll surprise you how badly it functions in their carb tune.

zkeller

iTrader: (47)

Final scenario is I am running 58s with a power valve plug. Car runs perfect. 12.5 to 13.0:1 under full throttle and the car is happy down low. Maybe they tune the carb with the stock cats? Did anyone verify? with the header and no cat, that would make sense why it required higher jetting.