Downpipe with cat ONLY on Cupra ST 290?

[Trettiosjuan]

Hi guys,

Here's my situation:
- I really like the car as it is stock already and don't wanna spend big money on it now, it is fast enough really per se.
- Love to drive twisty roads, even if this car is good for a turbo, lag is very noticeable jumping out of a NA car.
- I do think the ST is a little too quiet at times, but I don't want to spend big money on a switchable exhaust as I want to keep the OE refinement when taking it easy.
- Bit tempted by a conservative stage 1 tune nevertheless, simply because it is possible. But also would like to keep things 'stock' for warranty and insurance and such.

So I found this, the HG motosport Bull-X downpipe with HJS cat, all approved (EU6):
https://www.hg-motorsport.de/shop/p...-0-TSI-Downpipe-for-Golf-Mk--7-and-so-on.html

Looks like nice kit. In my imagination it should:
- Run fine without a tune (EODB?)
- Give some more real engine noise esp when giving it some, for me I rather hear it myself and keep it quiet to the neighbours, than the other way around.
- Make the turbo spool quicker, improving actual driving pleasure
- Make the engine breathe freer at top revs, I like to rev it out (without necessarily wanting to go much quicker)
- Approx +15 to 20hp
- Unloads the turbo instead of burdening it more (tune)
- Remains EU6 compliant
- Same price as a tune (for me) and I can always sell it later on, unlike a tune. And can always choose to do so later on...
- I will install myself (experienced), changing the downpipe back to stock is easier for me than driving 100miles to the remap place back and forth...

I'm going to ask them but any real experiences from users that confirm or contradict the above points or other feedback much appreciated!

Cheers

(edited with eu compliant version)

 

[AndrewJB]

EA888 TSI engine doesn't like bolt ons without tunes. My car ran funny with 200cel cat downpipe on Stage1 I had to get Stage2.

 

[Trettiosjuan]

Thanks for sharing. Funny in what sense? Mines manual so no DSG to confuse...
Also, a generic stage 1 pushing what it thinks is a stock engine would be quite sensitive to bolt-ons, did you try the original map with the DP?
Finally, what brand dp was it?
Sorry lots of questions,
Cheers

 

[Trettiosjuan]

EA888 TSI engine doesn't like bolt ons without tunes. My car ran funny with 200cel cat downpipe on Stage1 I had to get Stage2.

Funny, as in too much boost like this? :
http://www.vwroc.com/forums/topic/7109-aftermarket-exhausts-and-overboost-on-mk7/

 

[AndrewJB]

Yes it was really errattic, sometimes lots of boost, sometimes none, stuttering etc.

Stage2 tune on and all ok now.

 

[Trettiosjuan]

Cheers. Did some marathon reading on german fora, plenty of folks that have it work without a tune. Some issues though with hidden fault codes which would disappear with time according to the manufacturer...

 

[AndrewJB]

Yeh I had lots of fault codes and engine light a lot.

 

[Trettiosjuan]

Not suprised with a stage 1. That will up boost quite aggressively and as the turbo spins easier with the dp, boost shoots over and the ecu will throttle back as the wastgate won't be effective either...

 

[AndrewJB]

Same with stock OEM mapping as well though.

 

[Trettiosjuan]

Any other mods? DP was approved?

 

[Trettiosjuan]

Read tons on mostly German fora, where it seems common to just do the catted downpipe also without a remap or other mods. Key is that the catalyser is the real item, EU6, to not throw a code. Can't do additional mods either or you'll need a remap. Most seem very pleased.

 

[AndrewJB]

there no point buying a Euro6 downpipe though its not really going to offer any performance gains.

100cel or 200cel is the way to go or complete de-cat.

 

[Trettiosjuan]

I appreciate you input Andrew, but it seems obvious you're not up to date. A HJS EU6 cat (200cel), as used in the dp in the OP, has around 40% less back pressure than the original item, improves turbo spool up and reactivity and gives about 15hp at the top end. All while reducing thermal load on the turbo, probably improved mpg too if anybody cares. Edit: and will add some noise too, much needed on a stock ST.

Since it's ECE approved as a replacement part, it shouldn't automatically void warranty either.

 

[AndrewJB]

Any modification will void warranty. doesn't matter if its ECE approved or not its still not a factory part.

obviously if you have an issue just refit your OEM downpipe. My car has been in for warranty work.

 

[Trettiosjuan]

EU rules make that carmakers can't force to use their spare parts, as long as it's an approved part for the car model. Long shot of course, you can just put the original back. I'll probably get the HJS original that looks much closer to the OEM item. Bolts up better too and has a proper heat shield so...

 

[anri52]

Hello Trettiosjuan!
Its no probleml to drive with original software and HG motosport Bull-X downpipe with HJS cat (EU6)
I drove original software and this downpipe for a year before I installed Jb1tuningbox plus HG Intercooler.
The car feel amazing with only downpipe (I have done a lot of loggs with no issues) If you want you can see
how my Cupra preform with original software and Bull x downpipe...loots of race in youtube against
M3 e46, Gti 30 edition stage 1, Golf R mk6 stage 1, Porsche panamera S and more. (rian cupra)

 

[Trettiosjuan]

The car feel amazing with only downpipe (I have done a lot of loggs with no issues)
...

Porsche panamera S

Hello Rian,

No CEL is not the same as running great, so good lambda values etc, that's great!

Actually I found your vids and we had a little talk yesterday on yt You are my best reference and now I'm sure I'm gonna do it. Soon

 

[Trettiosjuan]

(rian cupra)

Oh, did it change the sound of the exhaust in any way for you subjectively? Thanks

 

[anri52]

Oh, did it change the sound of the exhaust in any way for you subjectively? Thanks

The sound is very close the original little bit deeper If you want more sound = new cat back

 

[Trettiosjuan]

The sound is very close the original little bit deeper If you want more sound = new cat back

Ok good, little deeper will do fine. Mostly quiet exhaust makes that I can accelerate faster without the wife complaining