HELP! Twin Turbo 350

[jnhj]

Here's the deal and what's going on.
Twin turbo blow thru set up on 350.
It's on my 71 Skylark.
Fuel system is Areomotive A1000, thru a couple of filters to Mallory 4309 adjustable bypass regulator supplying fuel to a Barry Grant 650 blow-thru.

This is all running thru my gas tank using 3/8 line.
Here's the problem.
Turn on the key, hear the pump, and within a second the carb is blowing fuel thru all four boosters, I' m talking flowing.
Spoke with Barry Grant tech idiots, told me to send it in and not to ##@! with it or they would not warranty it. Sent it in, came back. Same old crap!!!!

Any Ideas???

Thanks in advance,
J

 

[Chuck Leeper]

I'd use the same mfgr for all the components. [Aero pt # 13204 for low psi/carb app??]
3/8" lines are a serious mismatch for that pump. [Calls for -10]

Sounds to me as tho you are blowing the needles off the seats....
You don't mention what the actual fuel psi is????
How do you have the return plumbed?
How is the reg/carb plumbed?

 

[WFO]

Barry Grant 650 blow-thru.

Spoke with Barry Grant tech idiots, told me to send it in and not to ##@! with it or they would not warranty it. Sent it in, came back. Same old crap!!!!

Mistakes #1 and #2 right there...

Here's your answers:

Blow-Thru Carburetors

Carburetor Solutions Unlimited

Carburetor + Boost Tech Questions

 

[UR50SLO]

I agree with the other guys 3/8 fuel line is WAY too small. Your trying to ram firehose volume through garden hose size.
Replace with -8 or -10 to carb then to regulator. Making the regulator the last stop. -6 to -8 return to tank.
Make sure that your pressure at the carb is no more than 8psi.
I don't think carbs and boost for the street are a good idea but that's just me being critical of having AFR's right for driving and WOT.
~Scott

 

[cdr.performance]

Like other have said the feed line is too small but the return line must be equal to the feed line. Most of the time the motor need very little fuel and everything pumped to the front must be returned if it will blow past the needle and seat.

 

[pajo]

you might have your issue resolved by now but I beleive carbs can only take 7 psi before blowing or poping the needle.

 

[Dave Burns]

you might have your issue resolved by now but I beleive carbs can only take 7 psi before blowing or poping the needle.

If the carb isn't modified for boost you are correct. But there are plenty of folks out there running way over 7#'s througha carb. Have heard many bad things about BG blo-thru carbs. Quick and CSU have them figured out. I have a 650 here that is good to more than 7#'s and big enough to 800hp.

 

[pajo]

psi

can you tell what kind of tricks have been done to it .?

 

[Dave Burns]

I could tell you or you could just go to the turbo forums.....

TheTurboForums - Index

sign up, go to the "Carburetor + Boost Tech Questions" section and just read a step by step how to. Plenty of folks have done this with great success. Not trying to be a smart guy. Theres just a ton of info there about what works and what doesn't.

 

[pajo]

very good - thanks