SU Ram Pipes\Velocity Stacks

[fomoco_44]

Hi All 

Me again....must be getting sick of me by now.

I'm looking at getting some ram pipes for the HS6 SU's I have, and I noticed there are several on the market available. Main difference seems to be length of the pipe, as pictured.

 

Does anyone have any info\opinions on what is better?

I'm thinking of using the short type so that I can still fit them under my Redline Chrome filter housing, instead of buying socks.

[twosixty]

According to my memory of internet lore, shorter tubes=more hp , longer tubes=more torque.

 

NFI on whether this is true or a complete load of bollocks.

 

[sexual_sushi]

Norm the 12 second su dude's cheap velocity stack. If you look half way down the page he says...

he had a section covering SU's and they saw a 5% increase in power with the stub stacks and a 3.5% power increase with the longer air horns. Althouh the longer airhorns did make slightly more torque at a lower rpm.

 

If you are running a real racetrack where you have to slow down a lot then I'd say those would be the better option, but for the drag strip, HP will win out over low end torque unless you are really hoooking hard off the line and even then increased HP will normally win. I've tuned my car both ways and it's about a tenth slower in the 1/8 mile when tuned with a slight bias towards increased low end torque.

http://www.zcar.com/forums/read/4/2050673/page=1

 

http://www.zcar.com/forums/read/4/2051341

[fomoco_44]

Awesome...thanks guys

[260Coupe]

If you have a standard 240z filter housing ....use it......they make the more HP than ram tubes. This has been dyno tested numerous times (noise does not equal HP)

[fomoco_44]

Unfortunately, I only have the original Flat-top 260z filter housing...which I assume is unsuitable due to dimensions+square opening.

[DaveDimo]

make adapter plates. ive seen it done with stud sunken in the adapter plates then that gets bolted to the carbs. easy

[nuclear_z]

The longer the stack the better for Hp and Torque. Having a longer inlet track that is straight smooths the airflow allowing it to be sucked in faster...

 

Maybe the reason that a standard cover works best is the cold air??? I would bet its not the flow characteristics. Make a plenum with the stacks in it and it would be SWEET Have a look at the V8 supercar stacks and they're about 10cm long.

 

-EDIT- Cannot remember if they were Supercar stacks or otherwise that I saw at a race meeting recently...

[Scoota G]

I read on another forum that Ram Tubes are for smoothing out the incoming air flow but on yet another forum they say that it's a no no to polish the inside of your intake manifold as the air fuel mixture is mixed better traveling through the rough surface of a standard intake that still has the casting marks on it! Please Explain?

[Zedman240®]

Apparently, the rough surface is supposed to help turbulence in the airflow to help atomise the fuel so it burns more efficently. If you have EFI, you can polish as the fuel is already atomised better than what a carb can do. One thing you want to avoid is fuel condensing on the intake manifold walls..

[Scoota G]

Yea i read the same but what i'm asking is why would a ram tube be used smoothing the air out only to go through the turbulence stage in the manifold?

[RB30X]

You smooth out the air flow increasing velocity in the stacks before the fuel gets added in the carb then the air/fuel travels through the turbulent walled manifold and port.

[Scoota G]

And where did that info come from may i ask?

[chris240]

Oprah........

 

No, in all honesty I think rb30x is correct.. anything to increase velocity speed is defintely a plus. supercharging follows the same basic principle..

[(Locky)]

my car didnt come with any airbox or anthing off the carbs

 

so i got the redline ones

 

 

might try and rig up a bit of a CAI once its on the road

[RB30X]

And where did that info come from may i ask?

 

Combustion Engines 101.

[Zedman240®]

This might help explain..

 

http://en.wikipedia.org/wiki/Velocity_stack