Jeezer

im currently building my Ls1 turbo kit, and i got a comp with 230 intake and236 exhaust @.50 gross valve lift is int. .591 exh. .601. is that gonna be too big for boost?? i already know ls6 cam is the way to go, but wanna see if i could make power with what i got.

Any help would be greatly appreciated

conan

iTrader: (5)

What is the lsa on that cam. If its tight that will be a good cam, you want more lift and duration on the exhaust side to get all the boost out.

ls1290

iTrader: (20)

That is a pretty big cam for a 346. Even with a wide LSA, it is doing to have a lot of chop because of the large durations overlap. That cam is most likely going to start to kick in about the 3500 RPM range. It will make more power than the LS6 cam. If you have an A4, then you will need a fairly high stall, 3500 or so, to match the cam. A stall that high will loose a good amount of low RPM street manners IMO.

Shawn @ VA Speed

iTrader: (3)

need alot more specs,engine size,what heads,what size turbo,etc.
that cam probably wont work for a turbo unless you have a 400 inch engine with a big turbo

Jeezer

its a stock ls1 with valve train and cam. the turbo is a borg warner s375

Jeezer

lsa= lobe separation???

112

conan

iTrader: (5)

You got it. ^^^ I would get a new cam, the 112 lsa will bleed hard erned boost right down the exhaust pipe. Get some thing with a 114-117 lsa, and a little smaller on the duration then what you have.

engineermike

Not with a turbo!

engineermike

That cam is probably fine. People get scared of the 112 LSA, but 112 is already wide when compared to race cams running 102 to 106. And besides, it's not the LSA, it's the overlap that's important, and even then no one can show dyno results PROVING just how much overlap is bad for boost. In fact, INTMD8 did some cam testing on his twin turbo LT1 and every time he added overlap, it GAINED power. So...don't listen to the crowd. The only thing I can offer is that your cam's overlap MAY be too much if the exhaust pressure is very high. For instance, if you run a T67 turbo on a 408, the backpressure will be 3/1 over boost, in which case you could probably stand to gain power by reducing overlap to prevent exhaust reversion into the intake port.

Shawn @ VA Speed

iTrader: (3)

you can make hp with any cam on a turbo engine,power is not the issue,the issue is making power where you want it and spool,when back pressure is higher i try to lean toward a reverse split-which also helps with spool,as the backpressure goes down you can move toward a more traditional cam,but all of that depends on other factors like cyl head flow,type of intake and compression ratio.for a stock ls1 with a smallish turbo,a low 220's reverse split on a 116 with give you great power and drive with a seamless transition from no boost to boost,instread of having a dead spot.

Phil99vette

iTrader: (11)

Shawn has alot of experience under his belt, I'd listen to what he has to say.