Polo Intake Thread

[Timbo]

... 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%....

...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
....
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

I doffs me hat! Good work that man! Great analysis, supporting why neither intake nor intercooler mods have a dramatic impact with the KO3 in place, even on a chipped car. I'd just add to this, that while I don't have the flow data to support, if you look at the stock Polo exhaust, the greatest restriction in terms of reduced diameter through bends is from the turbo outlet to the cat....which is why replacing this section with a wider pipe liberates a startling number of ponies

[shaneth]

Nice work Spec, BUt i have one question not related to you analysis but to the thread.

WHats the purpose of having a CAI system??
Answer - to increase the flow of COLD air into the system, which in turn contains more oxygen and results in cleaner combustion.

Now its all well and good to say that the Turbo cant handle more Air. But that doesnt ruleout the fact that you cant improve the temp of the air that gets fed to the turbo.

Now lets take the stock Turbo inlet pipe. Half of it is metal. Now from what i know metal is a great conductor of heat so lets say the turbo inlet pipe is replaced by a silicone one the fact that you dont have the metal surrounding it and heating the air up as it passes through it is of benefit imo. Now if you increase the flow of it so that it passes through the pipe quicker which means it isnt being heated up as much would also be a good thing.

Now with regards to the seat air intake it increases flow which should mean more air and colder air gets there quicker and more effiecently.

So in my opinion we could go on all day about the turbo not being able to handle more air when the fact is that with regards to me im trying to improve the QUALITY of the air (i.e tempurature etc)

edit - Spec

Adding more air flow is only going to loose efficency.

Can you PM me and let me know how this can be. For some reason i just cant get my head around how more air in the intake is going to affect efficency. (i must have had a big night last night. )

edit 2 - im trying to get my hands on vag-com

[GT3]

...supporting why neither intake nor intercooler mods have a dramatic impact with the KO3 in place, even on a chipped car.

ha ha ha you've got to kidding. you've selectively isolated sections out of context from the broader analysis in order to justify the decisions you've made. it's obvious that intake and intercooler upgrades enable the K03 to run even more efficiently AND produce more power (the K03 is ideally matched to the pog's compression ratio, a K04 isn't).

shane, there's little point raising the proven benefits of deceased air temp, charge air volume etc bc it doesn't suit their argument (that's why those benefits are selectively ignored).

[Spec83]

ha ha ha you've got to kidding. you guys are interpreting these things in a way to justify the decisions you make, and point blank refuse to acknowkledge that intake and intercooler upgrades enable the K03 to run even more efficiently (the K03 is ideally matched the pog's compression ratio, a K04 isn't - which is why it's need signficant additonal mods to work efficiently).

Ahhh you are now speaking of ecu tuning technique... If the intake charge is cooler (same boost and rpm) it is more dense... This enables you to advance the timing more as you are reducing the chance of detonation or lean out the mixes a little bit as you don't need as much fuel in the cylinder.. This may go part of the way to answering your question Shaneth I just think a CAI is going to do SFA on a stock turbo as the intake is already OPTIMISED to the turbo charistics... If you wacked a GT3040 on then sure the intake would liberate some extra hp as it would be a restriction as now the compressor efficency curve probaly has it's peak efficency around 4500-5000rpm. The trade off is shocking lag and proably not much spool before 3000rpm.

This is the point i would be switching to a cable throttle and a microtec!!!

All of these parameters are inter-related... thats why it is hard to tune a microtec from scratch as you have to account for these things... its easier if you can crack the stock code and use the factory maps as a base!!! High boost with stock intercooler really requires a different tune to stock boost with intercooler and visa versa.... the APR/Revo/Ottengier tunes all use around 1bar of boost while leving everything else stock. This is the most mods you would want to do on teh exhaust side to a K03 1.8T as the turbo cannot flow anymore air even with a bigger exhuast.. Intercooler would make the air charge more dense hence more timing with a little bit more power... the intake would do nothing as again it is hardly adding any heat to the system - stock intake or CAI

[Wand Weaver]

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

My only thought is that's one of the most brilliant technical posts I've read on VWWatercooled in a long time, if not ever. Great work

I'd just add to this, that while I don't have the flow data to support, if you look at the stock Polo exhaust, the greatest restriction in terms of reduced diameter through bends is from the turbo outlet to the cat....which is why replacing this section with a wider pipe liberates a startling number of ponies

Does it really? I've not taken a good look under there, but having read through the (Vortex) buildup thread of the APR Polo, Guy mentioned, regarding the APR Exhaust:

Anyway, after a dozen dyno runs & a couple of changes this morning, there are no quantifiable gains to be made with stock turbo & stock intake.

(Page 4)

Although, he did mention that he believed the exhaust would be useful with the K04 upgrade, further down in the post.

Unfortunately, I think the APR Polo had its whole intake changed the same time as it got its intercooler and K04 update, so it's a bit difficult to say how much gains were gained by the intake.

Shaneth - I think Spec83 is referring to the chart, which shows that at maximum power, the choke line is already starting to drop of dramatically. The choke line represents the maximum volumetric flow rate from the compressor - in this case, the K03.

I noticed that you mentioned increasing the airflow so that it passes through the intake pipe quicker - it's interesting to note that the actual flow rate of an incompressible fluid through a closed system like a pipe is essentially constant - basically, you can increase the speed of the fluid by reducing the diameter of the pipe it is flowing through - sticking your finger partially over the outlet of a tap or a garden hose will dramatically show you that this is the case. But sure, air is a lot more compressible than water.

Still, it's quite obvious when you look at various Turbo inlet pipes that it's smaller in diameter at one end to the other - this is, as you mentioned, to increase the speed at which the gas flows through the pipe (but not the flow rate), by reducing the diameter.

I'm not so convinced in the benefits of a silicone hose compared to a steel pipe - sure, there might be an advantage as far as heat transfer is concerned (although the air isn't sitting in the pipe getting heated up for a lengthy period of time), but a silicone pipe might be more prone to hose collapse than a metal one, just due to rigidity.

GT3 - I'm not ignoring your data (do you have any?) that says that the inlet trumpet mod (or an intercooler mod) would enhance K03 efficiency. In lieu of any hard data to back your argument (even after I provided some data to support my point when you requested it) - it's a little rich for you to continue to claim that the people questioning the gains to be made from an intake mod are just being obnoxious and trying to justify our own decisions.

Given the friendly nature of Watercooled, and my own personal desire to keep it that way, I'll end my participation in this discussion with this post. I don't want to get into a flame war here, and if you strongly believe that the intake mods really are giving your Polo a tangible increase in power, then you shouldn't need me, or anyone else to justify that for you.

[shaneth]

and if you strongly believe that the intake mods really are giving your Polo a tangible increase in power, then you shouldn't need me, or anyone else to justify that for you.

I couldnt agree more mate well said. I was just going to post that everyone has there own experience and from this comes there opinion. Im impressed by the level of maturity everyone has displayed in this topic as it oculd have turn pear shaped very quickly. And please can we keep this level as well.

I think a few of us will have to agree to disagree. But i know what my Butt dyno tells me and thats all that matters to me.

EDIT - I will say before making your decision based on whats said in this thread (including what i have said) go into some other forums and do searches and see what other people have said about the TIP and CAI as you may be suprised. Especially in the MK4 Golf sections.

[Timbo]

I think Spec83 (and Wand Weaver's inital research kick start) fairly clearly set out the basis for the results I have found, or observed. And, while I have seen many posts in other forums about CAI and TIP, I've not seen any data supporting the claims. Despite what some of you might think (Neil!), I have an open mind and am perfectly prepared to recant where the data is produced.

That said, no-one here is forcing anyone to do anything and if you like and believe what you have done, go for it. Indeed, I suspect some intake work and the TIP will "smooth" the airflow so power feels more linear, but this is not the same as more power. Likewise, I understand the attraction of more induction noise and turbo whistle...but again, beware the psychological effect of these.

The Pog is a sub-30k car; if you are keen on improving its performance, as I am, you have to do this with a firm eye on costs, as it's all too easy to overspend without achieving real results (OK, so I'm tight!!). As I said, the real value of these forums is to pass on knowledge about what works, to avoid people making the same mistakes, being sucked in by marketing hype, or making decisions based on information which reflects little more than "tribal" loyalties (see "wars, chip" )

I spent the first 6 mths of ownership reading and listening, trying to understand what works. In the end, I've followed some accepted wisdom, and run a couple of experiments. I have posted my results regardless of the outcome, so others can make their own judgement.

The dump pipe was one such experiment. I, too, had read Guy's notes re the APR Polo...but there was also quite a bit of evidence from the MkIV world suggesting a dump might liberate something. I wasn't prepared to go for one of the built brand dumps+cat at $1k+, so had a custom job done for less than half that. There are many good reasons others will choose not to do this, but I was quite startled by the results...to the extent I doubted them! When these were confirmed, I became a believer, and posted as such.

I am obviously not a mechanic or tuner by trade, but I know a couple who are very handy, and I've taken the opportunity to discuss what I have discovered with them, and we have theorised about these results. One factor is the Euro vs Jap approach, where Japanese cars tend to be tuned down, based on intake and exhaust restrictions (the long running 206Kw gentlemen's agreement), whereas Euro cars are exhaust restricted due to EU emissions regs. So, the Euro car makers build intakes to deliver airflows that match the turbo, but restrict the exhaust side, whereas the Jap makers may do both.

I reckon this has been a really useful discussion. Despite what Neil suggests, I am very open-minded, really have no ego in this and more than prepared to change my views where the data supports, so please let's continue the discussion

[shaneth]

Indeed, I suspect some intake work and the TIP will "smooth" the airflow so power feels more linear, but this is not the same as more power.

Yes what you say could be true but more linear power is a good thing.

really have no ego in this and more than prepared to change my views where the data supports, so please let's continue the discussion

Thats the attitude everyone should have, good on you mate. I will be getting mine Dynoed, Just not sure when i am going to get time. And if i can get my hands on a Vag-com then i will be doing that as well and hopefully finding a stock standard polo in Brisbane so i can do the same test on it. Like you i only ever started doing this as an experiment and can tell you how it feels but i want to see it in black and white so that i can prove or disprove what i have done is worth it or not.

[GT3]

ok I'm going to say my bit and leave it at that.

..despite how my comments have been misconstrued from time to time, these are the facts as to what I've claimed:

1. I provided dyno evidence on the Forge TIP in which I said (power wise) there was no gain - although I acknowledged it provided other induction benefits, albeit marginal. I suggested that ppl were better off spending money elsewhere if improvements in induction were desirable (possibly air filter). I don't think this makes me an induction mod zealot, it demonstrates otherwise.

2. I also posted a thread (FMIC dyno) with before/after dynos after installing an APR FMIC. The results spoke for themselves, and Guy posted some excellent R&D on the thread also however it was followed by a defeaning silence from the anti-intake collective. The results demonstated that the effect of a FMIC was profound - and extended beyond the narrow measure that's very popular on this forum (the popular expressions are - bang for buck, kw atw, oh, and power, power, and sometimes even power).

3. I have never gone into detail or discussed the benefits of my air filter mod (BMC CDA) other than to suggest that there were a range of options available and ppl could experiment with and determine for themselves. Unfortunately, thereafter, various responses implied that if anyone didn't agree with the view that intake mods were useless, then they were ridiculed for 'wasting their money'. This was implicit and totally unnecessary.

That's why trying to explain these benefits to those who only see gains in terms of peak power alone is futile, ..things like a more linear, usable and wider power band just doesn't meet their narrow interpretation of 'power', so they dismiss these benefits outright.

I can only say (as much as this will be rejected by the anti-intake mod collective) that the intake mods I've done have produced amasing results. My engine has been totally tranformed from its awkward to use narrow power band (3000-5000rpm) to a now linear and free-reving power band that's an absolute delight to use. It has effectively transformed the car to the next level, ..and some of us 'can' ascertain whether the benefits are real and not just 'noise' and 'whistle'.

[mitch_gti]

GT3 no laughing here dude, only at HSV clubsport drivers when they attempt to take on the GTI.

I can vouch for intake mods on the polo, BMC panel filter, TIP and Cupra R have made a noticeable difference (for the better).