at what point does the stock IM and TB become a big choker? how high in the boost range would i have to get to start worrying about the stock pieces?

 

Bigger is always better when it come to the non-VTEC engines and boost. The LS manifold absolutely sucks when compared to the VTEC's. IMO a Skunk2 mani works beautifully. Our engine's aren't gonna be spinning to 9K+ so they don't need really any extra flow, unlike some of these VTEC ****** do..........(just kiddin guys ).

On a side note the LS head port matches very nicely to a skunk2 mani and flows a lot better. A good port job on the intake and exhaust of and LS head makes a good bit of difference. I did mine by myself and it turned out pretty nice. If you wanna learn how to port yourself, try this link and see what you think.

 

why would you put on an aftermarket Intake that makes you lose torque down low and gain power up high? Out of the LS's powerband thats the exact opposite what you want to do on an LS.

 

i understand that but on a boosted project it would help a lot

 

You do not lose anything with a skunk2 IM. The torque does not taper off as much in the high RPM. This also goes hand in hand with increased upper RPM HP. That is it. There is no losing torque.

 

Well like speadfreak said...the manifold sucks ***. I made roughly 260ish hp through it and ran 12's. Now with a fully built LS motor (thats spins to 9000 rpm) I am running a Venom intake and it helped overall.
Still using the stock throttle body now.

 

Dont doubt the stock intake manifold of the Ls. I made 509hp and 400+ torque and run up to 30lbs. of boost. I matchported the intake to the head and JG throttle body and called it a day. Im not saying if something better is available dont use it, just dont go blow money on something you may not need if your only pushing 15lbs.

 

i dont fully undertand the term port matching? does that mean that intake ports on the head are not the same size as the outlets on the IM and youre now making them the same size

when installing a larger bore TB do you actually use some kind of dremel type tool to actually make the opening in the IM larger?

 

That is correct

 

so which is larger/smaller? and wtf kind of sense does it make to have the inlet/outlet not the same size? to the engine mfgr's

 

I didnt say you lose torque up top, you lose it down low and gain hp in the upper rpm ranges which ar above where an LS can rev to if you don't do anything to the head. Keep the intake stock

 

I added a skunk2 to mine and noticed a marked imporvement in midrange power. Though top-end still lacked, this was when i was N/A. Lackof top-end on an LS is mostly due to those econo cams they got in'm

 

To put a long story short. If your gonna do anything to your LS then do the headwork. That is the the weakest link in that motor.
My head flows a pretty sick amount of air, but then again I spent a good amount of money to get it like that. Anyways, I set out to make a lot of the nonbelieving vtec lovers open their eyes.

 

maybe im grossly underestimating the flow of the stock IM & TB but what good is having a great flowing head if you cant get enough air into it?

 

you are underestimating the IM, it will flow enough for you, and in the right powerband. Like someone stated above work on porting the head and things of that nature.