Flow tested Na hardpipes

I ordered some polished hard pipes for my Na recently from Ashspec in the states and had them flow tested before sending. I was surprised at the difference between aftermarket and stock.


OEM:
drv: 336CFM
pass: 297CFM

AshSPEC
drv:492CFM
pass: 492CFM

I dont know how that equates to performance etc but I thought it was an interesting stat for anyone considering doing this mod.

Sorry if this has been posted before.

Item includes couplings in various colours,clamps and the 6101 mandrel bent ali pipes supplied powder coated in various colours including polished look ali.
I thought the polished look ali would be easier to maintain than the real polished ali.
$150 plus freight(to perth was $43.23)

 

Not that surprising. The standard ones have that horrible accordian section in it.

 

Unfortunately, they will make NO difference....

to your power output, they are a "bling" mod only

You could use a 4" stormwater pipe as your hardpipe and see no gains because the restriction in the intake prior to the hardpipes will always limit your flow.

Sorry to be the bearer of bad news, but you are now the proud owner of some "pretty" hardpipes

 

so where are the areas of restriction in a NA?

filter........?
factory t-piece pipe?
the 2 bends to connect t-piece to hardpipes?

not really alot of restriction in the way of airflow that im aware of, an yet the hard pipes still do nothing......something else must be causing a bigger restriction in flow

 

The pipes that go under the headlight from the t-piece to the hard pipes are narrower than the hardpipes and have some severe bends in them so they might be somewhere to look.

 

Anyone that has pulled a stock intake out knows how convoluted the inlet path is. Serious gains to be seen if you run straight from the throttles down to a pod filter (running either MAP or dual MAF setup).

 

agree, lots of bends and things that could be removed, BUT, the old question is if its worth it on a NA........if it gains you .5hp, or 5 hp.....thats the difference.........

 

You can test whether it will be worth it.
The idea is that atmospheric pressure is 14.7psi (1 atmosphere), and the bends and baffles in an intake rob flow, and increase the pressure differential between atmospheric pressure and the pressure of the air being forced/sucked into the engine.
This can be tested with a simple water manometer (water reservoir, length of clear tube and a wooden plank with graduations on it , all attached to a Vacuum source). 1 inch of water is equal to 0.036psi.
Measuring pressure differential between points in the inlet tract will identify where the flow restriction actually is. Eliminating the restriction can free up flow and reduce the pressure differential. This is in effect, 'Free Supercharging', and does not add heat to your intake like a turbo or supercharger does.
Neat, Huh?

What I'm saying is that it can be measured. No, I haven't done it, but it can be done cheaply and easily. For the record, if an engine has a pressure difference between atmospheric pressure and plenum vacuum of say 61 inches of water at 7000 RPM, then that is a loss of 2.2 psi, meaning engine is drawing in air at only 12.5psi. This is the difference between making 200HP and 175HP.

 

Wow Mitch!!

You're a brainiac and a half mate..!!
Thanks for that. So now all we need is someone to make this device and someone to donate a Zed for the project with the aim of testing the airflow through the whole system!
I wonder how much extra 'Neddies' we could come up with !!?:br:

 

Sorry to be the bearer of bad news, but you are now the proud owner of some "pretty" hardpipes

no bad news there as they were purchased for purely cosmetic purposes,any improvement in air flow would just be a bonus.

Having said that extra mods could be done if it was really worth it to improve air flow.

 

They have a website i can have a look at?

 

http://ashspecz.com/ashspec/NAHardpipes/NAHardpipes.htm

This is the link to the na hardpipes but you can navigate through the site.

 

But there is no improvement in airflow. No bonus applies....

We need Simmo to pipe in with an, "testing na hardpipes, Ohh dear"

 

61 inches is exactly 1.5 metres by the way





(Interestingly I only learnt about these last week when i was researching something related. Can't now remember exactly what though )

 

Here is a link with a basic instruction of how to make a water manometer.
http://obairlann.net/reaper/motorcycle/manometer.html
...used for motorcycle testing, but same for any application. I'd probably make it so that it has a reservoir of water at the bottom and only one tube, with vacuum applied to the end of that tube.

Test rig could be easily sat in the passenger seat, and poked up thru the targa Just make sure the rig is tall enough so that it doesn't suck the water into the intake.
5 points of measurement (or more if you are game ) will enable you to see where the greatest flow restrictions are:

1. Bottom half of stick airbox
2. Top (post-filter) half of stock airbox
3. after AFM
4. on accordian pipes (maybe use the nipple on the back of the accordian- i think it is for AIV's or EGR...)
5. at a vac point on the plenum

You need to get a reference 'atmospheric' water level. Make this '0 inches of water' (ie your calibration point). The further away from the 'open end' of the intake (ie moving from test point 1 through to 5), the greater the loss of pressure. This will be seen as a changing water level in the tube.
Measuring at a set RPM at each point (engine under load) will give you data. Difference between test points will show the pressure drop. i.e. 2 inches of water diff between test point 1 and test point 2 would show a 0.072 psi drop across the air filter (I made that pressure difference value up, for the record). 1 inch of water is 0.036psi.

I figure imperial is easier for people to understand, I'm a metric person myself, but as far as pressure goes, Im much more into psi than pascals. Oh, and atmospheric pressure changes with altitude, you can correct for this if you need to know actual pressures, but for measuring intake pressure drop, best to just keep it 'relative' to your base starting pressure.

 

Old school trick for tuning multiple carbs aswell, have one set up in the shed for doing up to 4 carbs at once.

 

Are you keen to do some testing Dave?
Go on... get some raw data for me

From what I've read, a 1.8m tube is ideal (72 inch), but restrictions in height of the rig can be compensated with less revs. Ideally, you would be measuring periodically across the entire rev range of the car, measuring how RPM affacts pressure drop in the intake.... I think the pressure drop wont be linear relative to RPM. Would make a nice graph if someone gets the data for me.:zlove:

 

Cutting into my intake piping to measure pressure?

Hmmm nope. Sorry.

 

when mine arrive i will let you know