hey guys ive need some advise on my carb turbo , ive serached and found no one running this setup ive got the chance to purchase a holley 650 double pumper from a mate with a 4 barrel adaptor plate so i wont have to change manifolds my question :



what are the advantages of using the 650 over the 4 barrel ( leak less , more fuel , easy to tune ?)



what are some common problems with these carbs and does any one have some sizes i should get it jetted to for a s4 turbo flowed out to t04 internals on 8 psi



cheers

There is a guy locally. His forum name is Kettleman. IIRC he is running a 650 double pumper. He is not boosted yet however has done some research and found what is needed to do the work. Go to the NW section and in the sub-forum there is a thread that is titled Holley denter-hung float bowls. That is the list of parts that you will need to boost prep your carb.



Wish I could be of more help, I am more os a FI guy though.



Z

650 is too big. A 600 would be heaps, maybe even too big.

there was a big article in "car craft" not long ago about blowthrough carb setups. I've read the article a few times (its sitting in the bathroom).



Basically you're going to want to run a boost referencing fuel pressure regulator with a return.



Also you want a carburetor with Annular boosters.



in a nutshell, your fuel pressure will need to rise with your boost pressure. so if at 0 psi of boost you're runing 7 psi of fuel, at 10 psi of boost you need to run 17 psi of fuel to keep the boost from blowing the fuel out of the bowls.





ALSO, 650 cfm is TOOOOOO BIGGGG. thats what they run on boosted BIG BLOCKS. I'm no expert, but what they've said is that SMALLER carbs will give you MORE FUEL because they help to keep the velocity up to draw the fuel from the jets (if i remember correctly).

GOOD LUCK! if i can get my hands on a scanner i'll try to scan the article

awsome if you could find and scan that would be mint

the scanner isn't plugged in (its not mine, so i didn't mess with it) so i tried to take pictures of it... but i have shitty lighting so it didn't turn out. I'll try to get the scans ASAP. or else i'll just have to transcribe it.