All about the bore?

[Robbie C]

Right, I've currently got a cat-back Milltek system attached to a standard cat and want to buy a race cat and DP next month.

As people have highlighted before, the Milltek DP and CAT is 2.1" at it's narrowest point whereas the BF is a wider 3" bore BUT to fit it to my cat-back system I will need a reducer.

My question is, if I mate the 3" blueflame DP to my 2.5" Milltek system will I actually see any gains over using a full Milltek system as the 3" DP has to be reduced to 2.5" anyway, causing backpressure.

I did a search and found http://www.seatcupra.net/forums/showthread.php?t=130476 where someone claims to have gained a few horsies by changing their DP from Milltek to BF when connected to a cat-back Milltek system but can this be right?

Pic comparing Blueflame, Milltek and standard cats (top to bottom):

Any thoughts/opinions on this welcomed.

 

[sandro123]

id say you were better with the bigger downpipe, the extra bore of ur catback will be pretty much useless if u go for the 2.1" bore. if you see my logic

as for back pressure im not totally sure the effect if any it would have.

 

[Fl@pper]

as for back pressure im not totally sure the effect if any it would have.

worth a read http://www.uucmotorwerks.com/html_product/sue462/backpressuretorquemyth.htm

 

[big eck]

The bluelame one looks tiny compared to the other 2 and why is there a strange "s" bend on the neck of the milltek one and not the others???

Doesnt the turbo control the back pressure and not the actual exhaust???

 

[EZ Tutty]

the blueflame is actually designed to mate to a 2.5inch exhaust i believe, therefore no reducer required

only the downpipe is 3inch, also the blueflame in the pic looks very very short :S

 

[Robbie C]

Cheers for the replies. So EZ Tutty, is the blueflame cat-back system 2.5" as well then? I always assumed it was 3" all the way through?

I've also noticed that Piper are now advertising their exhausts for the Cupra so I've emailed them to see what they can offer.

 

[PhilW]

Piper are doing exhausts for the ibiza? Not heard of that.


Cat back isnt much of a restriction, its the downpipe that is, so i wouldnt reckon you'd see any difference mating a 3" DP to a 2.5" compared to a 2.5" turbo back.

 

[EZ Tutty]

yes everything i've read on here confirms the blueflame steps down to 2.5inch,,, which is why i've ordered one to fit to my 2.5inch supersprint system.

also the top one in that picture isn't the blueflame one.. have a look at both of cuprabaz's posts in this thread - http://www.seatcupra.net/forums/showthread.php?t=130476&highlight=blueflame+diameter

 

[RichN]

Pic comparing Blueflame, Milltek and standard cats (top to bottom):

Any thoughts/opinions on this welcomed.

..original post where that image came from shows these are actually

"...3.0" AM dp then you've got the 2.1" rip off milltek dp and the bottom is the 2.0" standard"

 

[Robbie C]

ah my bad. Hmm so if the blueflame cat-back system is also 2.5" I think I may just get the BF DP and cat then

Piper are doing exhausts for the ibiza? Not heard of that.

Yeah there's a banner on the forum and I checked their website but they haven't updated their catalogue yet

 

[Olly20VT]

I've got a AM 3" DP (same as BF) with a jetex 2.5" cat back and it works well and the power figures are good with the turbo spooling up earlier and quicker.

 

[Robbie C]

Where did you order yours from Olly?

 

[AaronGS]

Planning on getting a new DP too. Was going to save for the Miltek, but reading this I may go for Blueflame. Question is, if I retain the Miltek cat-back and get the Blueflame DP and sports cat, is it going to be much louder than full Miltek system (and how much louder than standard DP into Miltek cat-back)?