Are they worth the money inside the plenum of a boosted motor?
Say on a 1.8l making around 400hp with a max rpm of 8000rpm running 30+ pounds of boost. (not a honda, old pushrod hemi toyota)
It would save quite a bit of coin just using radius inlets in the intake.

I'm not really looking for every last .5hp, but if they make a big difference I have no problem spending the extra cash.

Thanks
Randy

 

if you can grind the floor of the plenum to be radiused its pretty much the same thing. i think a lof of people opt for the stacks when building a custom manifold to look cool as well as have performance. but if you have a lot of material at the entry to each runner then make it the same shape and you accomplish the same thing, but you dont have any extras in there.

 

The velocity stacks work differently than just porting the floor, the stacks allow air to be pulled from 180 deg around the wall of the runner. Either way though, it's not the end of the world. Most people think you can build a crap manifold with velocity stacks and it'll work good because of them. I think plenum size and runner length are much more important.

 

i agree with tony. for most applications it isn't necassary... if you get a chance look at the velocity stacks inside the plenum of the champ car cosworth engines. they are long carbon fiber trumpets that reach almost to the plenum ceiling. they only boost 2psi and 6psi on "push to pass" but they make 750hp and 800hp on "push to pass".

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by weiRtech &raquo;</TD></TR><TR><TD CLASS="quote">i agree with tony. for most applications it isn't necassary... if you get a chance look at the velocity stacks inside the plenum of the champ car cosworth engines. they are long carbon fiber trumpets that reach almost to the plenum ceiling. they only boost 2psi and 6psi on "push to pass" but they make 750hp and 800hp on "push to pass".</TD></TR></TABLE>
damn that's nuts

so is it better to put the velocity stacks higher up in the plenum?

 

It's never as simple as more or less is better. What's "right" is right.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony1 &raquo;</TD></TR><TR><TD CLASS="quote">It's never as simple as more or less is better. What's "right" is right.</TD></TR></TABLE>
Hmmm...how much do you charge for intake mani's?