MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: dan_gt on October 15, 2010, 06:04:30 pm

Title: Gains from a downpipe?
Post by: dan_gt on October 15, 2010, 06:04:30 pm
Are there any gains to be made from fitting a 3" downpipe to a standard cat system? Or will it just sound a bit louder?

Worth doing or not?

Would more than likely heat wrap it at the same time as fitting.

Cheers

Dan
Title: Re: Gains from a downpipe?
Post by: edd666999 on October 15, 2010, 06:09:34 pm
turbo spool quicker, very slight gains. Best gains sen when remapped
Title: Re: Gains from a downpipe?
Post by: dan_gt on October 15, 2010, 06:22:13 pm
going straight for a stage 2 remap, so gauging parts needed for best gains.
Title: Re: Gains from a downpipe?
Post by: Janner_Sy on October 15, 2010, 06:32:56 pm
your slightly incorrect.  the performance downpipes come with a 200 cell sports cat to replace your exhaust downpipe from turbo up until the join in the centre of the car with the cat back system.

if there is no cat on it, it is a decat downpipe and will not be MOT compliant. :happy2:

as for is it worth it.  This is what i did.  i fitted a 3" Pipewerx DP mand the exhaust  note was lovely. not intrusive but much deeper.  alongside the stage 2 map and intake you are looking at 260Hp

for best gains @ stage 2 ideally you want a good remap, (GIAC, REVO shark performance IMO) , a good Intake (EVOMS, ITG or Twintake) and just a downpipe (mmiltek or pipewerx)  i personally from experience think the cat back part was a waste of mooney as all it produced was more noise and no performance
Title: Re: Gains from a downpipe?
Post by: dan_gt on October 15, 2010, 06:47:23 pm
your slightly incorrect.  the performance downpipes come with a 200 cell sports cat to replace your exhaust downpipe from turbo up until the join in the centre of the car with the cat back system.

if there is no cat on it, it is a decat downpipe and will not be MOT compliant. :happy2:

as for is it worth it.  This is what i did.  i fitted a 3" Pipewerx DP mand the exhaust  note was lovely. not intrusive but much deeper.  alongside the stage 2 map and intake you are looking at 260Hp

for best gains @ stage 2 ideally you want a good remap, (GIAC, REVO shark performance IMO) , a good Intake (EVOMS, ITG or Twintake) and just a downpipe (mmiltek or pipewerx)  i personally from experience think the cat back part was a waste of mooney as all it produced was more noise and no performance

This is what i was wondering, if a downpipe can be mated to a standard cat.

As you have stated, ill take it as a no it cant. So it will be a blueflame/pipewerx dpipe and cat.

Not going to bother with the cat back, as im in agreement with you and have never noticed much performance gains from a cat back system previously. Purely aesthetics only.
Title: Re: Gains from a downpipe?
Post by: h4rdy on October 15, 2010, 08:55:27 pm
Wow almost exactly my next question!

I am thinking about buying the pipewerx downpipe and cat for £465.

I don't really want an aftermarket exhaust but this sounded perfect.

So with all the other bits and bobs will I be able to achieve Stage 2+?

Or 'just' Stage 2?

The other option is asking Pipewerx to make me a decat with flanges like Hurdy had with a 'spare' cat for swapout in 15 minutes.

I will have all the other bits required for 2+.

J

Sorry ED30.
Title: Re: Gains from a downpipe?
Post by: Janner_Sy on October 15, 2010, 11:33:15 pm
i ran stage 2+ with an ITG intake, autotech HPFP and pipewerx DP.  Std IC, and std Cat back initially(although i wished i never bothered with the exhaust)

the one mod i would recommend though is the Intercooler.  when i logged mine and ran it on the dynos, i suffered heat soak and high inlet temps
Title: Re: Gains from a downpipe?
Post by: h4rdy on October 15, 2010, 11:48:52 pm
i ran stage 2+ with an ITG intake, autotech HPFP and pipewerx DP.  Std IC, and std Cat back initially(although i wished i never bothered with the exhaust)

the one mod i would recommend though is the Intercooler.  when i logged mine and ran it on the dynos, i suffered heat soak and high inlet temps

Thanks perfect I have a THS IC.

Did you ever have it dyno'd?

J
Title: Re: Gains from a downpipe?
Post by: Janner_Sy on October 16, 2010, 07:53:17 am
@ stage 2+ i have had it dyno'd at numerous outputs from 270 upto 287Hp on different rollers. 
Title: Re: Gains from a downpipe?
Post by: h4rdy on October 16, 2010, 09:14:00 am
That ties in with Revo's claims.

I spoke to somebody yesterday, Revo dealer, and they see no reason why 2+ wouldn't be achievable if all the other criteria is met.

So I would be happy, car looks standard too which is what I want.

If I got somewhere close I would be very happy.

Thanks again.
Title: Re: Gains from a downpipe?
Post by: Aparoon on October 16, 2010, 05:37:11 pm
Jay I ran that exact setup on your car, 3in pipewerx dp and cat built on the car to fit the standard cat back system.. You will see great gains, I was running this when I went stage 2+ and it was perfect, In my opinion the setup was spoilt when I fitted the full tbe blueflame, it was way too loud  :happy2:
Title: Re: Gains from a downpipe?
Post by: h4rdy on October 16, 2010, 08:30:36 pm
Jay I ran that exact setup on your car, 3in pipewerx dp and cat built on the car to fit the standard cat back system.. You will see great gains, I was running this when I went stage 2+ and it was perfect, In my opinion the setup was spoilt when I fitted the full tbe blueflame, it was way too loud  :happy2:

Hi C,

I don't want the car to look any different to standard, almost.

Thats one of the reasons for wanting to keep the standard exhaust.

I will probably get an SPS+ as well so I can run several options.

I.e. Standard, most of the time. Stage 1, Stage 2, and Stage 2+ which will be used the least.

The wife likes a go (more than me actually) and with the kids in I don't want her to feel its out of hand.

I think looking forward I would like a Hybrid KO4 running Stage 3 but I need to evaluate needs and why.

Thats for when I am thinking of changing the car!

It will change the car!

Hows the Oil Burner! :signLOL:
Title: Re: Gains from a downpipe?
Post by: GLIDN on October 17, 2010, 11:21:42 am
I have an ATP down pipe with no cat mated to standard cat back system.
I think it sounds stunning and in conjuction with stage 2 remap she now makes 160kw's @ the front wheels.
Found out on Friday.

Still running standard intake and filter.
Title: Re: Gains from a downpipe?
Post by: vRStu on October 17, 2010, 11:47:40 am
My system of choice the the Milltek DP & Cat mated to the OEM rear section.  You may well need to modify the mid section a little, mine looks like this -

(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fi97.photobucket.com%2Falbums%2Fl233%2Fvrstu%2Fjunk%2Fphoto.jpg&hash=e0dc2455e176fc6730cad67a5dcd6ffa5653d0c9)
Title: Re: Gains from a downpipe?
Post by: martziniuk on October 17, 2010, 11:51:54 am
I have an ATP down pipe with no cat mated to standard cat back system.
I think it sounds stunning and in conjuction with stage 2 remap she now makes 160kw's @ the front wheels.
Found out on Friday.

Still running standard intake and filter.

I've got a similar setup to you (minus the stage increase) whose map was that with and what dyno?

I would say most would agree that a 3" downpipe and decat gives the best performance if you can be bothered to swap the cat at MOT time. The spool is a lot quicker and low down torque is better too. Failing that you could try a 100cel cat and risk it passing emissions or a 200cel for definite pass.
Title: Re: Gains from a downpipe?
Post by: Aparoon on October 18, 2010, 11:30:55 pm
Jay I ran that exact setup on your car, 3in pipewerx dp and cat built on the car to fit the standard cat back system.. You will see great gains, I was running this when I went stage 2+ and it was perfect, In my opinion the setup was spoilt when I fitted the full tbe blueflame, it was way too loud  :happy2:

Hi C,

I don't want the car to look any different to standard, almost.

Thats one of the reasons for wanting to keep the standard exhaust.

I will probably get an SPS+ as well so I can run several options.

I.e. Standard, most of the time. Stage 1, Stage 2, and Stage 2+ which will be used the least.

The wife likes a go (more than me actually) and with the kids in I don't want her to feel its out of hand.

I think looking forward I would like a Hybrid KO4 running Stage 3 but I need to evaluate needs and why.

Thats for when I am thinking of changing the car!

It will change the car!

Hows the Oil Burner! :signLOL:

The cars awesome I love it, resisted getting it mapped soo far  too !

You might be happy with stage 2+ its more than fast enough... I thought I would miss the power but I don't at all, I do miss the dsg though at times!
Title: Re: Gains from a downpipe?
Post by: GLIDN on October 19, 2010, 04:08:48 am
I have an ATP down pipe with no cat mated to standard cat back system.
I think it sounds stunning and in conjuction with stage 2 remap she now makes 160kw's @ the front wheels.
Found out on Friday.

Still running standard intake and filter.

I've got a similar setup to you (minus the stage increase) whose map was that with and what dyno?

I would say most would agree that a 3" downpipe and decat gives the best performance if you can be bothered to swap the cat at MOT time. The spool is a lot quicker and low down torque is better too. Failing that you could try a 100cel cat and risk it passing emissions or a 200cel for definite pass.

I'm running APR Stage 2.
And the Dyno company in New Zealand Called torque performance. I have dyno'd all my cars for the past 8 years with them.
They are pretty accurate too. But it's not a hub dyno.

I don't bother swapping the CAt when it comes to our WOF (your MOT) time. As they are not yet that bitchy here. However if we cannot install Adaptors for porsche wheels. We can install remap or coil-over suspension, but it has to be certified. At a cost of $510. If any changes are made. IE height on the coil-overs. You have to get it recerted and again another $510 down the drain.