I made my 650dp for blowthrough, floats,jet extensions, .130 needle&seat, epoxy choke hole,drilled out pvcr .098, 2.5 powervalve, 67 jets primary 90 secondary,sx fuel pump 1/2 lines feed and return.performer rpm duel plane intake. carb has a milled choke horn. i have an evo hat with a one in spacer on a 302 15# of boost as soon as it is in boost above 10# it leans out bad 14.0-15.0. would that be from not having a good signal to the bowls ?

 

Are you flooring it all the way or slightly letting off when making boost? O.k., the million dollar ??, what fuel pump, bonnet and reg?

 

It could be that your power valve isn't opening all the way. Sometimes they can flutter as the boost comes on, since there is pressure in the bowl and pressure on the other side as well.

 

extreme velocity bonnet sx fuel pump mallory regulator with 1:1 boost reference. WOT an all test passes.

 

A couple things that I would start with:
Are you logging via LM-1 or other device?
What do the plugs look like?
Have you recalibrated the O2 sensor
What regulator are you using?
How long are you in the throttle and what gear before this happens.
Check float setting
Check Fuel pressure rising properly

These will help others provide better feedback. Also some of these may require someone to ride shotgun since there is no way w/o logging you can watch all that is happening.

Walt

 

I like the disclaimer there Walt. Nice job OGC would be proud.

 

Walt "Friend of Resident safety Nazi" Jon

 

floats are set properly.
lm-1 new 02 calibrated corectly
mallery regulator rising 1:1 like it should
plugs look lean and have some detination on a few
4-3rd gear pulls as soon as more than 6-8# its lean
i always have someone on the lm-1

this is my brothers car i am going to pull my carb off of my car and try it out.

 

do you need a p/v with that low of an opening threshold? in some cases there may be enough vacume at wot to hold it shut-ck your engine vac., use a p/v about 2 #s under that-you could block it and jet it up and see what happens with the afr's
did you make any changes to the hi speed a/b's, if not that might help also

 

Get rid of the dual plane intake and alls well

 

I think part of the problem is attributed to the power valve as well. You say the PVCR are .098". Are you using the methanol or high flow power valve to feed those restrictions? As mentioned above the smaller the power valve number the easier it is to close and it only takes roughly 2" of HG pressure difference from the bowl to the plenum to close it, and blown the bowl will always see higher pressure. 2" HG is just 1 psi. First try a higher rated high flow PV such as a 6.5 -Holley 125-165 and see if that helps. You're referencing the regulator to the hat..right?

FWIW the manifold choice has absolutely nothing to do with it leaning out at higher rpm.

 

:agree:

i had the same problem but i think i got mine fixed..also try hs air bleeds they helped me out a lot..

 

yes i am going to try a 6.5 pv and see if it works. high flow 2.5 holly. yes the regulator is referenced on the hat. thanks matt