I have a 1200 sedan with a 20b rotory turbo on a A12 engine blow in throw intercooler into 32/36 down draft weber, using efi fuel pump surg tank and carbi rising rate fuel regulater malpassi. need help problems when coming off boost ,I think it is flooding.

if you're not running a carb retun line then yeah! it will be flooding.

an EFI pump pushes about 3bar of fuel pressure, whereas a mechanical pump or an electric h-h-h-holley pump or the like will only push about 0.5bar.

the carby can easily hold back 0.5bar with the piston inside, but 3bar it will just force its way thru.

either run a bundy return line to the pot or change the pump to a h-h-holley or a carter or pierburg or whatever.

i picked up a 7psi carter pump (72gal/hr) for $80 brand new.

forgive me if this is a stupid question, but doesn't blow-thru turbo like u have it create a positive pressure in the fuel bowl in the carby as well?

not if you box the whole carby.

and as long as youkeep fuel pressure a few PSI above boost perssure is ok too.

sur does the troble i was having before was big lean outs were the fuel was being pushed back down the fuel line by the boost. does anyone have any part numbers 4 good fuel pumps 2 use.


Also If anyone is interested in buying the set up and motor pm me and i can send photos.

Where is your boost/vac reference coming from for the fuel reg?
If its before the throttle plate - there is your problem.
It needs to be after the throttle plate, so when you take your foot off the accelerator the boost signal drops to the fuel reg just like boost pressure will have dropped inside the carbie, otherwise you will be giving high fuel pressure to the needle and seat for a few seconds while it cant handle it.

It is hoked u to the intake manifold, i'm thinking it got more to do with the fuel pump psi now.

Thank for the imput!!!

fuel pump shouldn't cause a problem if the FPR is doing its job.

Ok



Thanks..