I have the Le5 Intake Manifold, and I'm adding a LSJ Extrude Honed Exhaust Manifold. I was wondering about head work. I'd like to have a basic Port and Polish done, but I wondering about portwork. If I Bring the Exhaust and intake mani to the machine shop, can they port match exhaust and intake side ports to the manifolds? Would this be a good idea?
2002 Cavalier "LS Sport"
port matching is always a good idea.
So That's all I ask for? Just bring the Manifolds along with the head to the machinist and tell him I want a basic port/polish, and the ports matched to the manifolds?
2002 Cavalier "LS Sport"
U dont want the exaust side matched to the manifold sir, the intake is fine though
mike
i make neons go fast.........
why don't I want to exhaust side matched to the manifold?
2002 Cavalier "LS Sport"
because it hurts exhaust "scavaging".
you want the opening on the head to be smaller than the opening on the header
LE5 is the 2.4 Eco VVT manifold, right??? I'll tell you right now you need little to no work on the intake ports, they match up perfectly to the intake manifold. if anything you might need a little bowl work and thats it. You don't want a polish on the intake side as the rough surface helps atomize the fuel, epecially in colder temperatures.
Currently #4 in Ecotec Forced Induction horsepower ratings. 505.8 WHP 414WTQ!!!
Currently 3rd quickest Ecotec on the .org - 10.949 @ 131.50 MPH!!!
scott (section8cav) wrote:because it hurts exhaust "scavaging".
you want the opening on the head to be smaller than the opening on the header
pretty sure you're referring to reversion.
the way most headers are made, the flange is a smaller I.D. than the primary I.D. so your anti-reversion is built in (more of a manufacturing cost side-effect than a primary concern I think.. but is beneficial anyway)
but the LSJ exhaust manifold.. not sure how that compares to the stock exhaust port.. it may be equivalent in diameter..
to the OP: why not just rock a true blue header? exhaust work should really let the engine breathe and maximize what you got.. going through the trouble of a port/polish to stick with a stock-ish exhaust is sort of.. dumb.
if anything, save the money you would use for the head work and do your ENTIRE exhaust system instead.. add injectors and a tune on top of that and you'll get much better results IMO
air flowing through the head doesn't really matter if the manifold is still a bottle neck.. and extrude honed or not, its still a crappy manifold with a crappy merge/collector. A header with a nicer collector and a shallower merge angle feeding into a larger diameter pipe is a better option for you.
save the port work when you get the whole shebang.. upgraded valves, valvesprings and cams should go along with that.. not to mention tuning.
basically what they said above, to help prevent reversion. unless u get a header with anti reversion chambers (big money) then the exhaust ports should be smaller (about an 1/8" smaller at least height wise) on the head then the inlet of the header, this is especially important on naturally aspirated applications.
mike
i make neons go fast.........
I wanted to use an LSJ manifold because it provides some gains, but i'd like it to look close to factory. Unless somone looks closely the only mods you would be able to see under the hood will be a K&N Intake.
2002 Cavalier "LS Sport"
