cumminsN14

Hello, this is one great site with a ton of info, ive been searching stuff for the last 3 months on here but cant seem to find much on what i want to do. Anyway im doing a LT1 swap on wifes iroc and here she brings a 86 z28 with a lg4 for me to play with. Now i have a few turbos laying around (holset HX35/40) and was wondering if anyone has ever ran the factory quadrajet with boost with the ecm still controlling stuff or does that need to go and run some sort of aftermarket blow through carb? It might be pointless to play with the 305 but i dont mind it, id like to take it as far as i can before i consider going bigger.

thanks

Damon

There is no way to modify a QJet for a blow-through application that I am aware of. Even when Pontiac introduced the 4.9L Turbo Trans Am (the "Bandit" car) the turbo was a DRAW-THROUGH setup with the QJet only metering the A/F in a normal manner and then the turbo system compressing the mix downstream from it.

You want a blow-through-modified Holley-style carb.

By the way, it's not that hard to build your own if you don't feel like slapping down the bucks for a professionally modified one. Any old Holley Double Pumper will do (not vacuum secondary) as a starting point.

Do a Google search on "Hangar 13 Mods" and you'll find the directions to do it. We have one running on my friend's blow-through 383 in his old Chevelle and it has run bottom 11s @ 126+. The wideband says it's metering accurately even under boost at high RPMs, so those instuctions are no joke.

cumminsN14

Thats what i figured, thanks for the heads up ill check it out!

Ozz1967

iTrader: (4)

The bigger issue that you're going to run into is the CA emissions laws. No where will your turbo set-up pass the visuals and if it does, you are probably going to have a bugger of a time with the sniffer test. I hate to say it, but CA is not a modder's place to live.