exhausts different bores?

[jonnyc]

^ That's my thinking TC, I think 2.75 is best???

For a K03 car I would say no bigger than 2.75" really.. Guys in the US would disagree though, I find the best way is to just try it..

Its going to be a trade off for top end power when you go smaller, as the K03 runs out of boost at about 5k revs its pretty pointless going large on the bore size.. For a K04 which still makes power at 7k its well worth it..

If I go big turbo on mine (GT3071R) then im going to go with an 80mm downpipe and 76mm system..

I understand the logic in 3" being pointless.  but would it cause any loss in power. 

It wouldn't loose power, but it would loose bottom end torque, so really its a trade off..

The best set up on a K03 car in my experience is a 2.75" downpipe with no cat, and a 2.5" cat back..

[Top Cat]

Thanks. 

[tony_danza]

Hmmm, no cat you say?

Do they bring up any warning lights/error codes that need fudging with VAGCOM etc.?

[RedRobin]

....

Milltek's full system is 2.75" on the GTI K03 and 3.00" on the Ed30 K04.

My assumption/expectation is that these sizes will be the result of their development and testing and will also take the established tuners remaps into account.

[snakedog]

Can someone confirm for sure that the ED30 system from the cat back is the same as the standard GTI system?

[Teutonic_Tamer]

Just to add my two pence worth:

In simplistic terms, with a smaller diameter zorst pipe, top-end outputs will be resticted, but low-range torque will be increased or enhanced.  At the other extreme, a large diameter pipe will have the opposite effect - much better at the top end, but also noticeably worse torque at the bottom end (and also mid-range on a normally aspirated car too).

The 'happy medium' will be to find an exhaust diameter which maintains a decent low- to mid-range torque, whilst not overly limiting top-end power.

Standard discaimers also apply - in that there may be other limiting factors too.  If you bolt on a 6" dia zorst, on sommat with a teeny weeny turbo - not only will you look like a chav, but it wont give you any of the 'expected' increases top-end.


And back-pressure - virtually all engines, including our beloved GTI mota, all need some back-pressure - for very teccy/nerdy reasons.

[danishmkvgti]

Can someone confirm for sure that the ED30 system from the cat back is the same as the standard GTI system?

I have sold one of my catbacks, but to answer your question, here are pictures of a stock gti downpipe and a stock ed30 downpipe, can you tell me which is which??  





And the catbacks were just as similar to eachother.

Buttom line the GTI and ED30 has exactly the same exhaustsystems.

[RedRobin]

Buttom line the GTI and ED30 has exactly the same exhaustsystems.

....No wonder fitting an aftermarket downpipe, such as Milltek TBE, releases more performance from the Ed30's K04 turbo etc.

[TT will correct me if I'm wrong]

[Janner_Sy]

miltek i think do a 3" for the Ed 30 where as i think its 2.75" for the gti

[Poverty]

milly dp is 3 inch, cat back is 2.75 inch for the k04 cars. Blueflame and apr do true full 3 inch tbe's.

[RedRobin]

milly dp is 3 inch, cat back is 2.75 inch for the k04 cars. Blueflame and apr do true full 3 inch tbe's.

....I think there's a reason why Milltek do what they do but I've forgotten it! Could be back-pressure related.

[danishmkvgti]

Since i have it and are over the moon with it APR RSC 3" TBE, then you're ready to go K04 also 

[Janner_Sy]

k03 the miltek is 2.75" bore straight through aprt from where they join as it reduces there to std 2.5 inch.  RR is right it is to do with back pressure, as it will give you a bit more torque from lower down the rev range than a 3" DP will. But a 3" should have its bonus's too. it should achieve slightly more at top revs,

[Poverty]

milly dp is 3 inch, cat back is 2.75 inch for the k04 cars. Blueflame and apr do true full 3 inch tbe's.

....I think there's a reason why Milltek do what they do but I've forgotten it! Could be back-pressure related.

Would be interested to know why, especially seeing as milly are doing a full 3" system for the focus rs.

[jonnyc]

milly dp is 3 inch, cat back is 2.75 inch for the k04 cars. Blueflame and apr do true full 3 inch tbe's.

....I think there's a reason why Milltek do what they do but I've forgotten it! Could be back-pressure related.

Would be interested to know why, especially seeing as milly are doing a full 3" system for the focus rs.

Almost certainly it's £££ related.. 3" turbo back is the way to go on the KO4 cars but Milltek have already developed a system for the GTi back when it was all KO3 and 2.75" was perfect for them..

The 3" Milltek downpipe for the ED30 / Cupra etc also fits the S3 so that's always a consideration when developing a new part as they only need to produce one jig