the shitty part i lost the cam sheet.

 

I went from a 9.6:1, 345 cu in to a 8.6:1, 392 cu in. I then switched out a stock 205/210, 117 lsa with a 119 1/2 install centerline to a 216/220, 114 lsa with a 111 install centerline. The boost was the same with the same size pulley. I then swapped out the stock intake manifold for a Mopar Performance intake. I lost 2 lbs of boost. I pulley downed a 1/2" and got my boost back. I then pulled my a/w intercooler off and gained another 1 1/2lb's. I now just use my w/m injection as my intercooler......Starting to think about a 35 shot to boot. lol

 

so you did a heads and cam swap along with the motor build? a cam swap will effect your boost presure(measurement of restriction) quite a bit but you should be making a fair amount more power even at the lower boost level. pully back up and it will be nuts.

 

You also did heads...... just pulley that bitch down and all will be good. The only thing wrong here is you have a way more effecient engine than before

 

Boost is a measure of backpressure.Obviously there is less backpressure.Pretty normal on a change like yours.The blower is still pushing the same amount of air though.

 

I don't feel that the compression ratio has very much effect on the boost level. It will effect the cylinder pressure alot, but boost level doesn't change much with a compression ratio change. The cam change, intake change, cylinder head change, etc., are the reasons in my opinion. I'd just check the faf readings. If you're moving about the same amount of air through that with the same pulley, that's your answer. Boost is a measure of flow resistance. You're flowing the same amount of air with less resistance, hence less boost. Of course this is why you upgraded blowers anticipating needing more cfm. Just pulley down and bring it back to 10psi or so.

 

yeah i plan to pulley down to a 2.6-2.7 for the track.

i was thinking the same thing zip. i didnt understand how boost would be change by cr. it still feels just as fast but i still am afriad to get wot. i think doing the 8 rib will also gain some boost.

as for the maf reading they are going to be very inaccurate. because i have the bov, which is open under vacuum and closed under boost. and i have a vacuum line after the maf that is also pulling in air from the breater/pcv set up.

 

if you use the same diameter pulleys and dont currently have any belt slip, there is no way for you to gain any boost by swaping to 8rib pulleys

 

well i know im having belt slip because the belt dust on my alternator. i will also be going with some smaller pullies. but i think the slipping is happenign in hgiher rpms.

 

Spray some VHT on your current belt. Work's for me. Just make sure your tensioner can handle it between shift's.