fcrotornut

So, my carb hasnt been tuned yet, im uust curious if anyone knows what my deal is.

ive got the rb prepped holley 600 double pumper setup, untuned.

ok, car runs, has a good bit of power only if i either floor it off the line, or downshift and floor it.

however if i keep it in gear and floor it, it just kinda puts along, doesnt really have much power.

has anyone with this setup experienced this, is it a tuning or jetting issue?

i was told it was propperly jetted from RB before being sent out.

thiis is on a gsl-se engine with a stock port.

fcrotornut

^^ anyone?

Alex-7

These cars typicaly don't do much unless you downshift and floor it.


I'm shure some good tuning would help out though. Either buy a book on Holley tuning (there are many available) and try it your self. Or find a shop with a dyno and book a time for a thorough session.



Good luck, I am in the same situation as you and saving for dyno time.


--Alex

fcrotornut

its slower then when i had my failing efi junk on.

its just got more torque.

fcrotornut

anyone have any advice

FB II

a damn good start would be with jetting. the 600cfm double pumpers from RB are meant for bridgeported engines so you are probably dumping way more fuel than neccessary. get an msd box for the leading side of the ignition and pick up the complete holley jet kit. goes from 60 - 99 or something like that. you probably dont even have to order it, just go to your local speed shop and see. this will be a great start.

Alex-7

Their current stock port GSL-SE Holley kit is a 600 double pumper. I'm guessing that's what he has and it is jetted acordingly.

fcrotornut

correct, i ordered a STOCK PORT holley kit from rb, pre-jetted according to them.

and yes, the stock port kit they sent me was a double pumper.

i would just shorten it down to dp'er but i would feel like a dirty **** saying it.

Paradox

iTrader: (1)

you 100% sure your secondaries are opening?

fcrotornut

sure am

FB II

anyone know if they change anything on them to make it idle leaner?

rmriggin

what do you have your fuel supply regulated at (I am assuming you are using the stock gsl-se pump). I also thought the double pumper that rb sold was for bridgeport? Check and see what jets they are running and if the secondaries are jetted also (metering block instead of plate). I would think that 66-70 jets in the primary and somewhere in the 80s for the secondaries jets should be around what you should need. Do the basics first though and make sure your floats are set correctly (fuel barely spilling out when the float sight is removed) and that you have the correct fuel pressure getting to the carb (4-6 psi for holleys). I believe that racing beat blocks off their power valves on their carbs so you may need to jet even higher to account for that. Personally I would run power valves on the primary and secondaries (8" vacuum or less power valves) and install the power valve blow out protectors . It is very likely that if it is a newer style holley it may already have power valve blow out protection installed (check with rb about that). Just my personal expirience from running a 4 barrel single pumper on my 12a stock port with exhaust (your should be easier to tune because you have an acelerator pump on your secondaries and most likely have mechanical secondaries). Mine was pretty tough to dial in because of having vacuum secondaries and lack of fuel when the secondaries opened (fixed the problem with of idle stumble by using the larger 50cc accelerator pump).

FB II

RMRIGGIN: did you change anything to get it to idle well? cause double pumpers usually run rich as fuuuug at idle.

fcrotornut

ive got a mallory 4070m fuel pump pushing 6psi

rmriggin

My idle mix screws are turned out 1 turn. I adjusted it according to a holley guide (start with both screws turned out one and a half times). Start the vehicle up and turn each screw equal amounts (either in or out) until the idle is at its highest. Once idle is at highest back screw out a quarter of a turn and you should be set. This worked very well for me and I no longer get a gas smell inside my car and the exhaust is no longer black-ish because of how rich it was before. Remember to reset the idle speed back to desired speed after idle mix is set. Oh yeah... Do these settings when vehicle is at full operating temp and with the carb hat and vacuum hooked up.

Paradox

iTrader: (1)

holy old thread. i'm also having similar probs. thinking of going to a larger secondary metering plate but i've yet to discovery what size RB uses. i was suggested a #9 which is worth a shot...

i also just found out my FPR was junk. so i bypassed it and now am just running straight hose to the carb. probably too much pressure but the car runs fine for now. atleast until i can get a better FPR

can anyone else out there with a 13b, stockport, 600cfm RB carb vouch that it will pull hard to redline? because mine dies off after 6K RPM or so. where my 12a would rock hard past 6