How can you add fuel to secondary without adding jet size. Rear powervalve is blocked

 

Why would you not want to add jet to rear for more fuel? Rear vent tube extension will add fuel.

 

Well, I've had my carb together for over a year and forgot what i've got done to it specifically . It has vent tubes and rear jet is 99 which
i think are huge for a 351/alum heads on 16lbs I want to add fuel at wot and actually go down in rear jets at the same time.

 

Drill some .050 holes right above the rear jets then you can reduce your rear jet size down.

 

do you have hsab's ?

 

Unblock rear pv, block hsab, you say you think 99's are to big but what is your afr @ wot? Please explain why your wanting to do this if afr's are correct.

 

Hsab are blocked and rear pv too. And afr's are hi 11's and sometimes Im pretty sure it hits 12.o. Im adding bigger heads and more cam and more boost than what I was currently running. Thanks for replys guys.

 

??????? i'd have to check but I think mine has 73f with a crutch pv (thanks Brent) and .080 pvrs . the rear has a plug and is jetted 89 .
the carb is a qft 750 with annular boosters , hsab's plugged , main wells drilled to .190 (not 100% sure) I'd have to check and the booster leg is drilled also.

AFR is mid 10's at 15psi ,runs high 8' at 155 leaving with 7psi.

 

You can open up the PVCRs and go down in jet. Is your P/V boost referenced? If not, I'd highly recommend that....

 

Rick racer.do you mean the open up the rear pvcr even though its has no pv?

 

No, the front ones...is your P/V boost referenced?

 

No the front isnt boost referenced. I am cashed out at the moment. Whats boost reference cost if thats what I need to do. A free fix is what I need right now

 

I think its time for some mainwell and booster mods or upgrades.

You may want to play with where your vent tube extensions are placed to catch the high flowing inlet air. Escpecially if they are near a turn you would want them position closer to the long side of the radius. My personal experience has been to place them in the middle of the inlet of the hat , flush with the hat. Though the setups I did them on where positioned at 4 oclock.

Not sure about your setup but we made just over 750ish whp with an 850 demon, front and rear IAB where either blocked or really small (cant remember), vent tube extensions, rear jets maxed , and low 80s up front with PV on gas. This squeeked out high 11s afr.

 

Search the BRPV threads, I know I've posted pics and info on pretty much my whole setup, just not all in one spot or thread, I should probably do that one of these days....anyhow, my BRPV is a crutch style, (flapped P/V Spring with a cap holding the spring outside the end of the P/V, held on/down by the main jets, I open the BRPV with turbine pressure, my vent tube extensions go right to the opening in my CSU carb hat, my air bleeds are kinda small but NOT blocked, and I'm running 99 rear jets on E85.