1.2 TSI Downpipe: yes or no?

[Samp1e]

I'm sorry, but I can't, since it's my and my friend's project and we are selling custom intake convejors online (via FB, IG, forums, etc.).
If you are interested in buying it, you can contact me via DM.

Since this topic is specifically related to the 1.2TSI Downpipe question, I ask everybody to be In Topic as much as possible.
For any further questions about other arguments, write a post on my Polo's topic or contact me via DM, please.

No problem! Can i have fb ? I can DM u over there.
Thanks

[Jay-Jay]

You can write me on my instagram account:
j.j.polo

[vis]

Yesterday I modified the intake with things I had at home, should work similarly to Jay-Jay one.
Only modified existing parts, and added a (not so) hard plastic conveyor (white paper template shown in pics)

finished assembly - the idea is to channel *fresh* outside air directly into intake hose without mixing with engine compartment *warm* air

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trimmed areas to allow direct intake - note notched fins to keep the conveyor lip flush with the lower surface

view from straight in

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conveyor paper template - note tabs to be placed into corresponding slots under the intake

conveyor paper template - note curvature
actual plastic piece was warmed to 60°C in water to better conform to shape

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trimmed top mount - note two slots where conveyor tabs will go

trimmed top mount - note trimmed horizontal lip to let air flow by unobstructed

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Materials used: 2mm thk (not so hard) plastic to fabricate the conveyor - was an old mouse pad (not spongy one)
Tools needed: metal saw blade, swiss knife, file, sand paper, cutter, scissors
Time to complete: 2 hours

Cool not to have used any screws to secure the conveyor, it holds positions just with its conforming geometry.
It's even a nearly totally reversible mod (save from the trimmed bits), just disassemble, take out the conveyor and re-assemble.

[Jay-Jay]

Well, in the end I installed a custom 2,15" (55mm) de-cat downpipe.





Against all of my expectation, engine runs very well. It has gained some torque and responsiveness and turbo spools much faster than before.
I am very pleased of how it performs now.

The only problem is the exhaust sound: it has become a lot more raspy and metallic.
I installed a sport resonator, which absorbed almost all of the metallic notes, but when I accelerate between 2500 and 3000rpm, the exhaust produces a very noisy metallic resonance, which really disturbs me.


What could I do to eliminate this obnoxious resonance?
My tuner says I should replace the OEM 6R GTI muffler with a sport one, because it has 2 or 3 empty rooms inside, which cause the metallic resonance.

What do you think about it?

I want to fix this before completing the ECU remap on the dyno.

[Pierlu]

Well done!

If the metallic resonance is like mine, will be an odd problem. I've not done the downpipe but only the exhaust and I've got it immediately. After like 4-5.000km seems to be reduced a bit (only a bit)

[Jay-Jay]

I did some tests.
With the resonator delete, the resonance is present at all revs and the exhaust is too noisy.
Putting back the OEM 6R GTI resonator, the resonance completely disappears, but the general exhaust sound becomes too quiet (like the stock exhaust).

So, the sport resonator seems to be the right compromise between the resonator delete and the OEM 6R GTI resonator.

Now I need to work on the muffler.
Will a sport muffler (which contains fiberglass or similar material) absorb high picthed frequencies and make the exhaust sound deeper?

[Pierlu]

I'm not sure to have understood your question but a sport muffler for sure will give you a deeper sound at low rpm and also a more powerful sound at higher rpm


This is mine (only muffler), I've gained a lot of sound at low rpm but of course not so much at higher because of the resonator.


[youtube]https://youtu.be/FVGH3hbTnKs[/youtube]

[Jay-Jay]

I'm trying to understand if installing a sport muffler could fix my resonance/high pitched tone problem I have only at 2500-3000rpm.

I'll listen to your video as soon as I come back home.

[Pierlu]

Oh ok, It should

[Jay-Jay]

Well, in the end I reinstalled the OEM catted downpipe.
I've not been able to find someone able to develop a good tune (I was experiencing overboost problems and other boost pressures problems related to the wastegate maps).
Plus to that, I've not been able to make the exhaust sound good: and with "good" I mean not raspy and metallic and not stupidly loud.

I preferred to switch back to my old and discrete stage 1, which better suits my car and my person.

I will sell my de-catted downpipe for anybody who might be interested. A new related topic will follow in the next days. In the while, you can PM me.

[suhaas307]

Hi Jay Jay,

I just had a case of déjà vu while perusing your thread.

Almost every step of the way, I was plagued by similar challenges faced by you.

Eventually, I opted for a beautifully made custom cat-less downpipe from a reliable tuner, who also flashed a tried and tested Quantum Performance remap on my Polo 6C 1.2 TSI (EA111).

It's hard to say how much my car is now making, but I would reckon somewhere in the ballpark of 130-140 hopefully. Unfortunately I do not have access to a dyno immediately and therefore unable to verify these figures.

I find your intake hack to be a smart little solution for a serious IAT problem that otherwise plagues our cars. For now, I have inserted a little plastic part into the duct area, effectively blocking off the duct from the engine bay while still keeping it open to the grille.

I had also purchased a Fabia vRS intake feeder pipe (piping from the grille to the air box) and fitted it to the K&N 57-S airbox I had installed last year. The pipe is significantly larger than the stock pipe on the 1.2 TSI. I'm not sure what gains could be expected from it as I do not have access to a dyno, but you could also perhaps consider the same upgrade, should you wish.

The cat-less downpipe has significantly improved engine performance, I must say. My butt dyno may be a liar, but I can tell that the car has responded beautifully to the new downpipe and map. I had also deleted the stock resonator from the stock exhaust on my car but just as you had experienced, I was not happy with the crude raspy rattle from the delete pipe and I was compelled to go back to the stock resonator.

I am unable to find a used GTI back box at the moment, and still struggling to find a viable solution.

[Jay-Jay]

Hi suhaas307,
when I wrote my last post in this topic, I summarized the long story I've been through.
In the end, it turned out that my overboost problem was caused by the Michel Hadid's remap and not by the catless downpipe. Michel stopped answering and helping me.
So, I asked another tuner here in Rome to work on my stage 1 map file and he has been able to create the perfect map for my needs, with more boost (1,25bar of peak and 1,15 of constant) and the pop&bangs, which is compatible with both OEM cat and catless downpipe. And above all, this map doesn't give me errors or problems of any kind.

I have not reinstalled the catless downpipe, since I've not been able to find the correct configuration for making it sound right.
At the moment I don't want to install it back on the car, untill I'll find a solution.
A friend of mine has an Audi A1 1.2TFSI with a catless downpipe. He fixed the raspy sound by removing the OEM muffler and moving the OEM resonator to the end of the exhaust, using it like a muffler. He sent to me few videos of his car and I'd say it really sounds good. But I don't trust smartphone's microphone anymore: I want to hear it in person and then judge if it sounds like I want.

Regarding the intake hose, I thank you for your suggestion, but I already installed that bigger intake hose from a Polo 6R GTI (which is the same of a Fabia VRS) and I believe it made a difference, especially in torque at low rpm.

Right now, with this new remap I can really feel the difference compared to my old conservative stage 1 (133hp and 233Nm). I would say that my engine has about 10hp more and about 20/30Nm more than before.
Afterall, when I'll feel I'll have completed few works on my engine, I'll test the car on the dyno to see what is the real output.

Let me know if you'll test yours: I'd be curious to hear more from you!

Cheers