Which Downpipe?

[Manny_ED30]

Hi Guys

Looking at downpipes (Eventually a whole catback) for my ed30. Eventually stage 2+

Can anyone advise on a 3.5" down pipe with a sports cat? - Spoke to relentless on this and they only offer the 3.5" decat and claimed that a 3.5" with sports cat will hamper flow massively. Any truth to this? Trackslag also offer the 3.5" decat.

Ideally I want to keep the CAT for MOT purposes and keep the noise down.

Thoughts on this please

Thanks in advance!

[colesey]

I’m not sure you will need a 90mm downpipe at this level of tune, possibly more for hybrid turbo type power levels. Also the flow of sports cats can be quite variable depending on their quality. BCS by all accounts uses a good one and their 75mm downpipe should be a good option for you, especially since you are aiming towards a full system in the future. The build quality is excellent and certainly up there with the Termignonis on my Ducati!

[pudding]

Mucking around with my tuner recently, we pulled an easy 400lbft from my Ed30's engine.  Apart from an APR downpipe (with cat), 6R intercooler and Loba pump, it's standard.  We've since dialed it back as it's too much cylinder pressure for standard pistons to cope with in the long term, but it was interesting to see what the OEM bits n bobs are capable of.

If you don't regularly rev the engine past 5500rpm, intakes and catbacks may not be necessary for your driving style.  You certainly don't need them for Stage 2+.   If you're told otherwise, find a better tuner.

[Manny_ED30]

Mucking around with my tuner recently, we pulled an easy 400lbft from my Ed30's engine.  Apart from an APR downpipe (with cat), 6R intercooler and Loba pump, it's standard.  We've since dialed it back as it's too much cylinder pressure for standard pistons to cope with in the long term, but it was interesting to see what the OEM bits n bobs are capable of.

If you don't regularly rev the engine past 5500rpm, intakes and catbacks may not be necessary for your driving style.  You certainly don't need them for Stage 2+.   If you're told otherwise, find a better tuner.

Strong number that. Did the 6R cooler bolt straight on or did any mods need doing? Would this be a better option than the branded coolers?

I’m not sure you will need a 90mm downpipe at this level of tune, possibly more for hybrid turbo type power levels. Also the flow of sports cats can be quite variable depending on their quality. BCS by all accounts uses a good one and their 75mm downpipe should be a good option for you, especially since you are aiming towards a full system in the future. The build quality is excellent and certainly up there with the Termignonis on my Ducati!

Agreed. Opting for the 3" system throughout.

[pudding]

Yep bolts straight in.  You can either use 6R intercooler hoses, or modify the GTI ones by cutting the bayonet fittings off the ends.   The big brand intercoolers like Wagner, Peron, Integrated Engineering and APR will resist heatsoak better, but at up to 4x the cost of the 6R cooler, it's a cost vs benefit thing.  If you drive the car normally and enjoy a squirt when traffic conditions allow it, the 6R is more than adequate.   If you want to put in the best 1/4 mile times on the track, then a bigger aftermarket unit would work better.

[colesey]

Some interesting downpipe options here

http://www.fahrzeugtechnik-zinram.de/epages/61798191.sf/de_DE/?ObjectPath=/Shops/61798191/Categories/Audi/Volkswagen/Golf/V_GTI_20TFSI