Downpipe question

[rynaqui]

I am going to be running RS2 spec very soon. My mechanics have mentioned that a downpipe larger than the outlet of the exhaust side of the turbocharger will only cause lots of backpressure and no gains at all and suggested I keep the stock downpipe (Will be at around 360hp). I was planning on a 3" downpipe and exhaust.

Can any of you guys give me some advice on what's the best route and reasoning behind wanting to go 3" instead of staying at 2.5"? Also taking suggestions on the best type of exhaust for 360 upwards of about 450hp

[caterpillar]

http://www.exhaustvideos.com/faq/how...-pipe-diameter here you se the pipe areal.... so i will say 3" are too small.... you will have earlyer boost,( 300-500 rpm) and more torque, and more HP... 2,5" are way to small pipe..

[rynaqui]

Thanks for that useful link, I think 2.5" is too small but some more advice wouldn't hurt

[|Maku|]

http://www.max-boost.co.uk/max-boost/exhaust/exhaust.htm

[GazzaG60]

firstly rs2 spec wont do 450hp. bigger turbo is needed for me on that.
3" minimum straight through.

im no fan of rs2 spec. its my opinion. I cant see much value bang for buck but im sure others will disagree.

id rather keep the cash for fuel and buy more modern parts.

speak to prj about a turbo/map that's good for your needs.

[Error404]

My mechanics have mentioned that a downpipe larger than the outlet of the exhaust side of the turbocharger will only cause lots of backpressure and no gains at all

It sounds like they are getting confused with N/a and forced induction. With a turbo you want minimum back pressure. For high 300s 2.75" RS2 downpipe is even on the small side.
I would go 3" all the way through

[GazzaG60]

I went 3 before 300. Skipped 2.odd. Pointless spend

[rynaqui]

Thanks for all the help and think they might have got confused but thanks everyone for clearing up a few things! Will be at about 360 and I think 3" should be the way forward

Gazza think that close to 450 is possible with a billet wheel and maybe head porting but for now hope to get the car ready for a normal RS2 spec

[GazzaG60]

personally id sell the rs2 turbo for good money and the manifold and go wagner with t3 flange and then pick you choice of turbo.

I have no head porting, 7a cams, wagner inlet, cooler, exhaust and precision sc6152 so a bit bigger.

stock aby intercooler did about 380 ish the the car pulled really well on mainly stock bits. with the bigger cooler, inlet etc and 7a cams it felt flatter till I got to just under 2 bar boost then above 5k it went like a scouser with your stereo.

balance as usual is key. don't forget your fuel pump and that. with an 044 and lots of map trimming the performance went up and up till some tosser in a stolen car hit me.

[rynaqui]

personally id sell the rs2 turbo for good money and the manifold and go wagner with t3 flange and then pick you choice of turbo.

I have no head porting, 7a cams, wagner inlet, cooler, exhaust and precision sc6152 so a bit bigger.

stock aby intercooler did about 380 ish the the car pulled really well on mainly stock bits. with the bigger cooler, inlet etc and 7a cams it felt flatter till I got to just under 2 bar boost then above 5k it went like a scouser with your stereo.

balance as usual is key. don't forget your fuel pump and that. with an 044 and lots of map trimming the performance went up and up till some tosser in a stolen car hit me.

Sorry about your loss, always the law abiding that gets done over

I mainly went for this setup to up because it was really all bolt on and not much modification was needed except for the wagner IC. I don't think I'd ever really want more power than a billet RS2 can offer but we will see

[EvenM]

Good thread I'm also on my way to upgrade to a rs2 setup

Does anyone sell complete exhaust from a 3 inch downpipe ?

[Rusty]

Turbo turbine is much bigger restriction than the exhaust, so gives almost all of the back pressure. 3" is what you want.

Even k26/7 don't make 450 on good fuel, do next get saving for a 3076 for those numbers.

Enjoy the RS2 setup, you'll not want much more on anything other than a drag strip or track.

[macspring]

I spoke with Hank of Iroz Motorsport on the phone last week, :roll eyes:, as I bought a billet RS2 turbo from hom.

I discussed how I was unhappy with the fit of the 034 3" downpipe in my B4 chassis.

He said he bought the jig from them, and after checking saw the problem, and has made a new jig that means that his 3" downpipe will fit a B4 , without fouling on the subframe.

Just saying........

But talk to him directly to satisfy yourself. His welding is a work of art.

If you use his down pipe it is a one into one, so will not bolt up to the oem two into one exhaust system connections.

HTH.

Following your upgrade threads.

While it was mentioned that one can do better than an RS2+ spec, what I like about this spec is that it all bolt on for us that can't / don't have the time to start fabricating and being creative to overcome 'issues'.

cira 390bhp, should do you for going around the island on your roads.

[rynaqui]

I spoke with Hank of Iroz Motorsport on the phone last week, :roll eyes:, as I bought a billet RS2 turbo from hom.

I discussed how I was unhappy with the fit of the 034 3" downpipe in my B4 chassis.

He said he bought the jig from them, and after checking saw the problem, and has made a new jig that means that his 3" downpipe will fit a B4 , without fouling on the subframe.

Just saying........

But talk to him directly to satisfy yourself. His welding is a work of art.

If you use his down pipe it is a one into one, so will not bolt up to the oem two into one exhaust system connections.

HTH.

Following your upgrade threads.

While it was mentioned that one can do better than an RS2+ spec, what I like about this spec is that it all bolt on for us that can't / don't have the time to start fabricating and being creative to overcome 'issues'.

cira 390bhp, should do you for going around the island on your roads.

Spoke with him as well, will probably get one from him he mentioned it is a direct replacement

For now will stick with what I have as funds won't allow anything further for the moment . I think it is at around 360hp according to Will but no idea and probably won't dyno it just happy I've got more power .

Need to update the thread as we've started the car and just a few bits to go