I have two sets of velocity stacks for my custom intake manifold I'm making. Here are some pictures comparing the two designs. I really like the weber stacks because they have a very nice taper to them, which has shown to perform very well. What I dont like about them is there 0.035" wall thickness. This is where the ross stack design shines. It is very thick walled, and durable. Do you guys think it is possible to build a durable and reliable intake manifold using the thinner stacks?










48 IDF 5":
http://www.tperformance.com/st...tacks/

2.0" stacks:
http://www.rossmachineracing.c....html

Regards,
Justin


Modified by Justin Olson at 4:19 PM 11/20/2005

 

i dont know if this helps with your question, but i've noticed that most if not all the aftermarket manifolds i've seen that have the stacks inside use the type like the thicker of the two... as in almost straight runners with but a shorter stack as opposed to a small stack and a tapered runner

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Justin Olson &raquo;</TD></TR><TR><TD CLASS="quote"> Do you guys think it is possible to build a durable and reliable intake manifold using the thinner stacks?</TD></TR></TABLE>

Depends on who the welder is, but yeah it can be done and it can be dependable.

 

I think .035 is way too thin to be reliable for runners with a plenum. Especially in a turbo application.

 

I prefer the Ross ones. The others look way too thin.

Remember, the thinner your intake manifold the louder your motor will be. A thick intake manifold will absorb the sound of combustion and the valvetrain noise. A think intake manifold will not, making the motor very loud at any throttle position.

 

i also have the rmr stacks. they are a good company. i just dont like how its so small. not sure if yours are the same size, mine are 48mm.

 

Justin,
Ive used the thin ones several times with no problems. Ive also used Ross ones and they are just as nice, but im with you on the nice taper on the weber ones.

 

I would go with the weber ones. I think it is a much better design all around, except for maybe the way thickness, but I wouldn't see that being an issue.

 

I'm sure most of you guys have worked on hondas before. Ever notice the steel brace that honda puts between the intake manifold and the block? You're crazy if you think a set of .035 aluminum runners with a plenum attached to the end of it would last very long w/o cracking. Those .035 stacks are not designed to support any type of weight at all.

 

How about adding a thick brace on each end of the head flange to carry load placed on the runners by the throttle actuation?

Justin

 

That could definitely help. Vibration should be a concern as well. On Rado's manifold, I had to use 90 deg. runners to clear the frame rails with this particular head. All I could find in the size/radius i needed was 16ga (.065"), so I welded a .125" thick strip along the outside bend (the part that stretches on a bend and is thinner) of the runners down to the flange. Gives a little extra piece of mind at least.

 

damn your a badass... I hope to be as clean and pay that much attention to detail as you someday

 

Very true Tony, should of took the weight into consideration. Some reason I thought he was going to make itb's.

 

jun manifold with velocity stacks:

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by weirRacing &raquo;</TD></TR><TR><TD CLASS="quote">
</TD></TR></TABLE>

I would think that little gap between the velocity stack and sheet metal can't be good.

 

that gap should be fine. it doesnt mess with flow much at all if any.

 

So what are your guys favorite stacks to use for custom manifolds?

Justin

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by weirRacing &raquo;</TD></TR><TR><TD CLASS="quote">jun manifold with velocity stacks:
</TD></TR></TABLE>

anyone know how they cut a motor like this?

 

The taper is nice but how much of a benefit is it while running forced induction?

 

They will help. Whether the engine is forced induction or not, the gas velocity depends only on flow geometry and engine RPM. So long as you avoid choking the flow, a venturi can only accelerate the gas and make it move through the valve easier.

 

Does anyone make thicker stacks with a taper?

 

That kink in the runner where the tube starts on the Jun manifold doesn't look too sweet.

The Supra manifold does this samething. Is there actually a purpose to it besides maybe making the manifold fit in the car?

 

bandsaw?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adictionbass &raquo;</TD></TR><TR><TD CLASS="quote">

anyone know how they cut a motor like this?</TD></TR></TABLE>

 

sawzall haha

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Justin Olson &raquo;</TD></TR><TR><TD CLASS="quote">So what are your guys favorite stacks to use for custom manifolds?

Justin</TD></TR></TABLE>

my own...