# Down Pipes info......



## Titanium GTR (Sep 27, 2009)

Evening/Morning all

After some info on GTR down pipes pleaseeee. i have seen some nice Milltek ones and know many other comapnies do to but i have few queres/questions that people could help me before i decide if the worth it:

1) How much extra noise do you get with Down pipes and y-Pipe vs just Y-pipe? is it Nice noise, horrible Noise, etc i heard it been called a "drone" by some people and "hevean2 by others?

2) What kind of Power gain do they give you, my cars 576hp for instance what am i looking at if i fit them and had it mapped for them?

3) People with them already and a y-pipe how do you intend to pass MOT emissions test??? Wouldnt that technical be a straight through exhaust? unless you have a slight muffler for noise). My cars nearly 2 years old so i am starting to think if i tune and get them what are the repercusions for MOTs etc (early thought i know) But not all us know a kind garage owner that will stick the emissions probe in another car when we get it MOTed Lol 

4) Makes, i know Milltek do them and GTC i think, but who else and is there differneces that justify costs etc?

5) Lastly any kinda GTR owners out ther within 50 mile me (Surrey/London) have a Down pipes and want show me the noise difference? pleaseeeeeee

Thank for you help if you answer and i am sure other on the furum will apreciate the info too

:thumbsup:


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## tomgtr (May 24, 2008)

Sat in a car with race catted AMS dowpipes. Sound of that was very bearable and not THAT much of a difference power wise.


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## charles charlie (May 3, 2008)

Been stood near to John Hanton's decatted GTR and that sucker was loud. Not sure you'd get on many tracks with that noise level.

Also bear in mind that leaving 2 downpipes cats in place means you'll pass the MOT emissions test when needed, but not without.

One way round that is to keep an OEM y-pipe and swap them over at MOT time...


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## Elliott_GTR (Dec 13, 2009)

1. Decatted downpipes are a lot louder. But I love it.

2. They give quite a reasonable power increase I think +20ish Bhp. 

3. I have kept my original y-pipe and my original cats, just in case I have emissions trouble.

4. I have the GTC ones, they look great, very reasonable and easy-ish to fit.

5. Not in your neck of the woods. 


One thing you'll find though is that once you do the DPs with your current system you'll be maxing out the injectors, so you might want to consider injectors and intakes at the same time.


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## David.Yu (Jun 28, 2001)

Don't see the point in fitting them with the stock cat-back exhaust still there? That is a restrictive piece and you will gain more from changing that first (and less labour).


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## Elliott_GTR (Dec 13, 2009)

David.Yu said:


> Don't see the point in fitting them with the stock cat-back exhaust still there? That is a restrictive piece and you will gain more from changing that first (and less labour).


Oh, I thought he had the full Miltek system....


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## [email protected] (May 16, 2003)

Elliott_GTR said:


> 1. Decatted downpipes are a lot louder. But I love it.
> 
> 2. They give quite a reasonable power increase I think +20ish Bhp.
> 
> ...





wow Ell i'm impressed you really know your tech 

James hope your thread doesn't turn into another who's is best  Iain's 321 steel dp's look awesome, we have some cast 90's happening as well as already effective current batch we've sold loads.


VR is a caged beast, unleash the potential by decatting. They are labour intensive 4-5 hours and if bolts too tight/snap engine will need dropping.

100% needs a map tweek to turn off cat codes and check log afr & injector.

Personally prefer full decat, but race 150/200 cell cats is option but can be alot more expensive, can help with db's a touch and give something between full decat and oem cats power increase.


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## Elliott_GTR (Dec 13, 2009)

Benji Linney GTC said:


> wow Ell i'm impressed you really know your tech


You see! I do listen when I drive you nuts with my endless questions!


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## jackg (Feb 1, 2010)

I had downpipes and full system on mine. Makes a lovely noise but too noisy for trackdays and sprints.

I'm going to put my old miltek full system on my new one but leave standard downpipes and I really hope it will be under 105db! Hopefully there won't be too much loss of power as my old one was really quick, never dynoed it but it felt REALLY quick

My downpipes are for sale through Ben at GTC

Jx


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## charles charlie (May 3, 2008)

I'd have downpipes, intakes and injectors in a snap, if it wasnt for my need for track days.


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## [email protected] (May 16, 2003)

jackg said:


> I had downpipes and full system on mine. Makes a lovely noise but too noisy for trackdays and sprints.
> 
> I'm going to put my old miltek full system on my new one but leave standard downpipes and I really hope it will be under 105db! Hopefully there won't be too much loss of power as my old one was really quick, never dynoed it but it felt REALLY quick
> 
> ...



yup Jack has available some very rare Inconel downpipes if anyone genuinely interested, pm Jack or myself





















Cast 90 dp's










Catted










Zircotech coated


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## Litchfield (Feb 26, 2008)

James to be emissions friendly you can refit the standard Y-pipe at MOT time or we will also have a Y-pipe with perforated 100cell CATs. We use these new ones on our high power Subaru models and these don't increase back pressure by much even at 450-500bhp (obviously you'd have 1 per bank on the GTR).

Regards

Iain


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## Elliott_GTR (Dec 13, 2009)

How do you get those flames?!?!


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## Litchfield (Feb 26, 2008)

Rich fueling or spark plug in exhaust


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## Elliott_GTR (Dec 13, 2009)

Litchfield said:


> Rich fueling or spark plug in exhaust



Hmmm, switchable "Flame" map.......


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## Titanium GTR (Sep 27, 2009)

Am Getting the rest the milltek exhaust fitted for sure but when maybe in few weeks. so after that will be down pipes in little while if i like them. i am wait from a call from litchfields now lol. Iain is a veryyyyyyyy busy guy.

And Ben no it wont be who best post. i respect you working in the GTR scene and we have had our problems in the past but i hope we can put that in the past. what i have said before maybe was harsh and unnessary, "Sorry" Its just Litchfield are more my stlye ok. but i respect your work.


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## _shaun_ (Jan 16, 2007)

Elliott_GTR said:


> How do you get those flames?!?!


LOL I was thinking that....:lamer:

My car is at Nissan at the moment:nervous: so looks like it won't be till April time till I do anything

Not sure at what point it will be too loud for me as I use the car everyday etc and would like to get on to do some track days...:squintdan


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## DWC (May 18, 2009)

Dont those Flames affect the paint work. Ha Ha


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## vxrcymru (Sep 29, 2009)

If one is already running around 585, fitting downpipes will require injectors and fuel pumps too, sounds a lot of money for an extra 20-30 bhp.

I'm no expert but am I correct in whats required and gains?

Whats the maximum bhp of the stock turbo's 650bhp?


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## _shaun_ (Jan 16, 2007)

At what point are you starting to put strain on the gearbox? Around 650ish??


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## Litchfield (Feb 26, 2008)

The turbos will run out of puff around 620-630bhp ish (depending on the dyno you use) and how hard you push them. If you push them to hard they just produce to much heat and bad air.

The gearbox is much stronger than people think but I would recommend 700bhp cars at least have uprated circlips. It is the Torque that will start to make the Clutches slip but the standard ones seem to cope with 600lbft very well.


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## enshiu (Aug 20, 2010)

Benji Linney GTC said:


> yup Jack has available some very rare Inconel downpipes if anyone genuinely interested, pm Jack or myself
> 
> 
> Catted
> ...


Pm me benji_linney for catted downpipes.


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## Steve (Sep 21, 2001)

Why burn it out of the exhaust, it's expensive enough !LOL


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## JapFreak786 (Aug 29, 2003)

my lame input into this thread,heard andrew186's 35 with downpipes etc fitted and when I get a 35,i'm getting downpipes as that noise,oh my it was amazing!!


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## gtrsam (Oct 27, 2005)

Why does all manufactures of catted DP use low quality cats ? Use HJS cats it has 3 mounting points for the metal core instead of one. You can clearly see it the pictures in this thread.Also keep in mind that a lot of catted DP has gonne bad after track days just search NAGTROC. If they used HJS cats instead it would have been a different story.


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## splking (May 11, 2012)

Hi Titanium GTR, 

I have recently had downpipes fitted by Iain onto my full 90mm race Milltek system, and it sounds epic. I love it... keep rolling the window down everywhere because i love the noise. Its actually very bearable on motorways and under 3k, but it comes alive when you want it too so i think its perfect. I would say i do like my car noisy and i am not too fussy about motorway drone but you are more than welcome to come for a ride in it. I live in central london however... PM me if you are keen to come in and go for a spin. 

I will be taking my car to Litchfield for MOT purposes so I am not too fussed about MOT requirements. As for the track day limits, i'm not sure how it will fare but if they dont ask for me to rev it above 3.5k i cant imagine it being too bad. Maybe Iain can create a map that only allows the car to rev to 3.5k rpm in Park when you attend a track day so that you can get through the sound test. Then you can switch back after? Just a thought. 

H


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## Steve (Sep 21, 2001)

splking said:


> Hi Titanium GTR,
> 
> I have recently had downpipes fitted by Iain onto my full 90mm race Milltek system, and it sounds epic. I love it... keep rolling the window down everywhere because i love the noise. Its actually very bearable on motorways and under 3k, but it comes alive when you want it too so i think its perfect. I would say i do like my car noisy and i am not too fussy about motorway drone but you are more than welcome to come for a ride in it. I live in central london however... PM me if you are keen to come in and go for a spin.
> 
> ...


LOL, how naïve are you ? 
Not only do you have to pass a static noise test but most circuits have a drive by noise test as well. Bedford for example is 87db, trust me after 25 years of track day experience, you either have a noisy road car and love it or a very quiet (but [email protected] fast) track car and live with the fact that you cannot sound your gorgeous screaming V6!!
:squintdan


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## ACspeedtech (Aug 25, 2011)

Steve said:


> LOL, how naïve are you ?
> Not only do you have to pass a static noise test but most circuits have a drive by noise test as well. Bedford for example is 87db, trust me after 25 years of track day experience, you either have a noisy road car and love it or a very quiet (but [email protected] fast) track car and live with the fact that you cannot sound your gorgeous screaming V6!!
> :squintdan


Agreed! After years of speaking VERY nicely to the noise testers at circuits (stopping short of buying them chocolates but only just) to try and get 900+hp Evo's on track with all sorts of combinations of baffles/motorised flaps/ temporary bungs/ and a few other sneaky things... The best way is to just build it quiet in the first place, total overkill and hope for the best.

A track friendly system can be built, although also consider a sports catted y-pipe, this can be built to be suitable to 800hp, knock a lot of volume out and leave you road legal too.


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## Steve (Sep 21, 2001)

At Bedford you don't even get a chance to speak, talk (argue) with the noise police as one black flag for noise and you is off home !!

I am at Snetterton this Saturday and it's at 105db, so fingers crossed and all that !!


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## ACspeedtech (Aug 25, 2011)

Good luck!  ...and take Haribo


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## barry P. (May 9, 2010)

Just ordered my set of downpipes from Russ Fellows, should be ready for delivery next week.


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## charles charlie (May 3, 2008)

Nice work Barry. Russ's stuff is beautiful.

Are you going decatted?


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## barry P. (May 9, 2010)

charles charlie said:


> Nice work Barry. Russ's stuff is beautiful.
> 
> Are you going decatted?


Yes, had a chat with Russ this afternoon and if necessary in the future he can weld in some sports cats in the Y pipe, although the Y pipe visually would appear to have cats because of the resonator bulge. I'm hoping that with a decent Ecutek map at tick over the emissions will be low enough to pass,however we will cross that bridge when we get to it!


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## charles charlie (May 3, 2008)

Sounds fair, the great thing about Russ's stuff is the option to change it


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## mindlessoath (Nov 30, 2007)

Titanium GTR said:


> Evening/Morning all
> 
> After some info on GTR down pipes pleaseeee. i have seen some nice Milltek ones and know many other comapnies do to but i have few queres/questions that people could help me before i decide if the worth it:
> 
> ...


tl;dr

but i did hear mention of drone from dowpipes that were too thin in material. so a bunch of dowpipes are < 1.8mm thickness drone and those with > 1.9mm don't drone as much or at all (probably depends on the rest of the components)... but its still loud due to no restrictions (again depends on the rest of exhaust system choices).
is this true? dunno but id imagine less drone with thicker pipes.

someone/shop from Canada (vex tuning) made incollnel downpipes... lightweight, great for heat management and incollnel is strong... dunno if it would cause drone or rasp as downpipes. hope they give out sound clips.


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## mindlessoath (Nov 30, 2007)

also cats should be in the mid pipe not the downpipes as they all have or can potentially have issues with the heat and pressure going out. some have just pushed out the cat insides and were out labor and downtime due to not being able to drive it and wait for replacement parts... cost in labor not free etc. cat in the pipe resolves this issue 100% if good quality product.


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