Polo Intake Thread

[Wand Weaver]

sure and they often change the intake too

Perhaps a larger K04 is able to shift enough air to take advantage of the larger intake.

I was saying that the K03 struggles to shift enough air above 5500RPM, even with the standard intake pipe. By fitting a larger turbocharger, that point becomes no longer relevant.

The question posed in this thread was whether changing an intake, WITHOUT changing the turbocharger, was likely to make a measurable difference in power or torque output. Like the OP, I'm not totally convinced that it would.

Let's put it this way - if a pump can only move X amount of fluid a minute, increasing the potential flow rate of the pipe feeding fluid to it won't make any difference, unless the pipe was restricting the flow of fluid to a figure less than X to begin with.

What I, and the OP would like to find out, is whether the standard intake pipe restricts the flow to a figure less than X. IF, and only if it does, will an intake mod make any difference.

[Timbo]

This is with the standard intake - giving the turbo even more air isn't likely to make it shift more air - it already can't shift the air coming through the standard intake pipe.

There, my friend, is the nail hit on the head!

[GT3]

Perhaps a larger K04 is able to shift enough air to take advantage of the larger intake.

I was saying that the K03 struggles to shift enough air above 5500RPM, even with the standard intake pipe. By fitting a larger turbocharger, that point becomes no longer relevant.

Unless you have engineering data that supports your claims re air intake capacity of the K03 (that's frequently conjectured but never verified), then you're simply making an assertion.

[Adam]

Unless you have engineering data that supports your claims re air intake capacity of the K03 (that's frequently conjectured but never verified), then you're simply making an assertion.

boys boys! let's settle this on the black top! end quote from F&F3

[DaveMack]

I think Guy's Vagcom idea is the best way of settling this. Other than that ... it's really just all hot air - pun intended.

Dave

[Wand Weaver]

Unless you have engineering data that supports your claims re air intake capacity of the K03 (that's frequently conjectured but never verified), then you're simply making an assertion.

You want some data?

Fine. Here's some flow rate vs "boost" pressure airflow maps, for both relevant turbochargers.

KKK K03

KKK K04

Note that the K03 Graph is sideways - the X axis should be the airflow, in cubic metres per second (one cubic metre being 1000L), the Y axis being the pressure, expressed in bar.

The K03 doesn't shift nearly as much air as the K04 - note how the choke lines drop dramatically as airflow hits around 0.1 and approaches 0.15 cubic metres per second, even at 2.2 bar boost.

The K04 exceeds that amount - and can handle more boost than the K03.

Now I've put up my data - would you like to put up data on the intakes? I'm interested in whether the intake really does choke the K03 - but to say that the K03 struggles to shift air regardless of the amount of boost you throw at it isn't speculation, as you just suggested but fact.

The compressor just isn't big enough.

[GT3]

You want some data?

The compressor just isn't big enough.

well good for you lol. in my view, there's many variables at play and its the interaction between all these things, such as intake, MAF, charge temp, compression ratio, turbo efficiency etc etc that work togther to bring about gains. when isolating separate components, that gets overlooked

[Spec83]

well good for you lol. in my view, there's many variables at play and its the interaction between all these things, such as intake, MAF, charge temp, compression ratio, turbo efficiency etc etc that work togther to bring about gains. when isolating separate components, that gets overlooked

You hit the nail on the head... The MAF is the biggest restriction in the system... say the MAF accounted for 40Pa and the filter for 10Pa (50Pa total intake resistance)... if we reduce the filter to 5Pa we have reduced that part of the intake by 50%... however we have only reduced the total intake restriction by 10%....

Taking informtation from Guy and WandWeavers posts lets look at the efficency curves attached where i have marked out a few major points... The K03 is 72% efficent at loads lower loads (less than 2/3 max power) hence low lag, lots of down low torque... As Guy mentioned a stock 1.8t in a polo flows 120g/s at max power.. From the attached graph you can see that the polo is already dropping off the back of the efficency curve. Adding more air flow is only going to loose efficency. This may also be the reason why the polo does not benefit from an upgraded exhaust as it simply can not do anything with the incresed air flow. This would be true for both chipped and non chipped cars...



On a chipped car note that efficency of the K03 is the same for that at stock boost... this is why the stock intercooling system still works fine with the car in a chipped state... it is no less efficent and produces no more heat Also, the efficency band is moved higher in the rev range... where previously boost is starting to fall off it stays strong - hence the increse midrange poke of a chipped polo everyone raves about!!! And of course we all know the more air we flow the more power we can make...

This is also where adding more fuel when adding more boost becomes important... If the maps are not compensated then it will add the same ammount of fuel for stock boost - but we are now flowing 25% more air at any given point. Too much air and not enough fuel will put the A/F above 14.7:1. Not enough fuel is added to make the mixture to make it more dense in the combusion chamber and pre-ignition of the mixture occures as it enters the chamber and not on the compression/spark stroke. This puts untold stress on the engine components as it is now opperating out of time... two cylinders are firing at once etc etc... this is when things tend to break big time

It is also intresting to note that a K04 is more efficent at stock boost levels than the K03... Just by replacing the turbo you should make a little more power

The only thing de-restricting the intake would do is let the engine rev a little more freely and make boost come on a fraction earlier... above 2/3 max power it will do nothing as the turbo is past it's best

Thoughts.....???!!#$%#$

[DaveMack]

Hmm ... guess I shouldn't have flunked maths, Mark.

BTW ... I still have a DVD that you'll be wanting to see sometime (purely VWW business ppl ... nothing rude )

Dave

[Spec83]

Hmm ... guess I shouldn't have flunked maths, Mark.

BTW ... I still have a DVD that you'll be wanting to see sometime (purely VWW business ppl ... nothing rude )

Dave

You have a PM dude....

I put so much into that explanation too hahahaha... Basically anything that increases the kg/s to the right of the max power dots is a waste of money because you will loose efficency and create more heat that you can't get rid of..... if you add a bigger intercooler then it may help to add an exhaust also.. but i doubt it


No dyno tests should be necessary after looking at the curves... its all in black and white