Down Pipes - The short answer?

[dh58]

Is there currently a recommended one?
Can we get these used?
Can we buy these from the USA or do we need special ones for the Oz market?

How much do they cost to install?

I haven't been following on this but I could be due for an early xmas present

[BMW86]

AR downpipes are the best around and fit RHD.

Anywhere between $350-$400 is reasonable for installation.

[Stuart@BMRAutowerkes]

this has been covered many times... but in short

- recommended is AR Design... these fit our RHD cars with minimal issues
- you can buy them used if you can find them used
- you can buy AR ones from the US... other brands will not necessarily be as easy to install. Riss racing, Active, etc fall into the 'other' category
- install will be anywhere up to 500

[dh58]

Originally Posted by BMW86

AR downpipes are the best around and fit RHD.

Anywhere between $350-$400 is reasonable for installation.

Hmmm.. So if you take your car in for a service you'll need to take them off and on.. So thats 350-400 each time.. Can these be done DIY?

Yes it can: http://www.n54tech.com/forums/showthread.php?t=145

[dh58]

Originally Posted by bmroxm5

this has been covered many times... but in short

- recommended is AR Design... these fit our RHD cars with minimal issues
- you can buy them used if you can find them used
- you can buy AR ones from the US... other brands will not necessarily be as easy to install. Riss racing, Active, etc fall into the 'other' category
- install will be anywhere up to 500

Appreciated. AR design keeps coming up.

It seems the install is going to be the ongoing cost

[Honny]

Originally Posted by dh58

Appreciated. AR design keeps coming up.
It seems the install is going to be the ongoing cost

First of all, if warranty is going to be something you're going to worry then don't go ahead with DP's. Theoretically its not something where you can take it off-on where as like a tune you can.

Before you get DP's make sure you have a tune of some sort or else your dash is going to light up like a xmas tree (Assuming you want catless)?

[dh58]

Originally Posted by Honny

First of all, if warranty is going to be something you're going to worry then don't go ahead with DP's. Theoretically its not something where you can take it off-on where as like a tune you can.

Before you get DP's make sure you have a tune of some sort or else your dash is going to light up like a xmas tree (Assuming you want catless)?

Hmm.. looking at the DIY it looks like it COULD be done but its a major hassle.


Looking at the AR used from the US is about 700ish then with shipping to oz its another 150ish.

[MrBlonde]

It's not something you would DIY, it's a shitty job.

[dh58]

Originally Posted by MrBlonde

It's not something you would DIY, it's a shitty job.

After reading your comment I checked the DIY thread, nearly 40 steps. You could be right

Another question, what is the difference between:
Downpipe and downpipes?

I've seen some that are just 1 that split into two, then there are others which are 2 seperate ones?

[ansch]

Originally Posted by MrBlonde

It's not something you would DIY, it's a shitty job.

^^^

Just crawled under the car yesterday installing the sway bar and had a peek at the turbos. I'm ok with a spanner (installed suspension parts and intake for various cars) but the position of the turbos and dp are just awkward to diy without proper hoist and tools.

[DTNJNQ]

Originally Posted by dh58

Are reading your comment I checked the DIY thread, nearly 40 steps. You could be right

Another question, what is the difference between:
Downpipe and downpipes?

I've seen some that are just 1 that split into two, then there are others which are 2 seperate ones?

The one that splits into 2 is for the N55. The 2 separate ones are for the N54.

[Honny]

Originally Posted by dh58

Are reading your comment I checked the DIY thread, nearly 40 steps. You could be right

No offense because theres a DIY thread doesn't mean its as easy as ABC. Anyone with DP's will tell you its a bitch to do.

[DTNJNQ]

Looking at this picture of the OEM downpipes against the after market ones. The OEM ones seem to be similar in diameter. Has anyone tried to gut the cats on the OEM downpipes?

[BMW86]

It's a 135i not a cheap rice car, I wouldn't be bashing out the cats when you can get some quality downpipes. Also, the cats the in the downpipes actually cost big $$$, you're better off hanging onto them if you need to go back to stock.

[Harlequin]

Originally Posted by BMW86

It's a 135i not a cheap rice car, I wouldn't be bashing out the cats when you can get some quality downpipes. Also, the cats the in the downpipes actually cost big $$$, you're better off hanging onto them if you need to go back to stock.

[sparoz]

Don't forget the akra downpipes. Same price as the AR, but only 2.5" and not 3". Power curve should increase all over, while the 3" may have a small shift in power curve - you lose a bit in the low end, but gain in the top end.

Being the same price as AR, I would make sure the akra would be in the mix of your consideration. Not to mention it is the only aftermarket DP that has expansion bellows.

AR has replied me, their high flow cat options is 200 cell and still 7hp off from catless. Catted pipes are more expansive than catless ones. Another option if you don't want to go catless is to have AR build a HJS 100 cell for you which would be roughly 2k. hp loss should be around the 3-4hp mark. You might still get a CEL though.

[Stuart@BMRAutowerkes]

There's a Sydney workshop at the moment working on a prototype of a gutted oem downpipe. They have access to a dyno too so we can see the results of that!

Besides all downpipes end as 2.5inch.... And if you've seen how minuscule an oem n54/n55 turbo is, they don't really need much more diameter than 2x2.5" piping.

[dh58]

Originally Posted by sparoz

Don't forget the akra downpipes. Same price as the AR, but only 2.5" and not 3". Power curve should increase all over, while the 3" may have a small shift in power curve - you lose a bit in the low end, but gain in the top end.

Being the same price as AR, I would make sure the akra would be in the mix of your consideration. Not to mention it is the only aftermarket DP that has expansion bellows.

AR has replied me, their high flow cat options is 200 cell and still 7hp off from catless. Catted pipes are more expansive than catless ones. Another option if you don't want to go catless is to have AR build a HJS 100 cell for you which would be roughly 2k. hp loss should be around the 3-4hp mark. You might still get a CEL though.

Hmmm, never heard of akra. So if the diameter is higher than 2.5" you will lose HP?

So what is the point of having down pipes then? Just to have them remove the cat?

Originally Posted by bmroxm5

There's a Sydney workshop at the moment working on a prototype of a gutted oem downpipe. They have access to a dyno too so we can see the results of that!

Besides all downpipes end as 2.5inch.... And if you've seen how minuscule an oem n54/n55 turbo is, they don't really need much more diameter than 2x2.5" piping.

OOoooo do you know when this will be out?

[RaihaX]

Originally Posted by sparoz

Don't forget the akra downpipes. Same price as the AR, but only 2.5" and not 3". Power curve should increase all over, while the 3" may have a small shift in power curve - you lose a bit in the low end, but gain in the top end.

Being the same price as AR, I would make sure the akra would be in the mix of your consideration. Not to mention it is the only aftermarket DP that has expansion bellows.

AR has replied me, their high flow cat options is 200 cell and still 7hp off from catless. Catted pipes are more expansive than catless ones. Another option if you don't want to go catless is to have AR build a HJS 100 cell for you which would be roughly 2k. hp loss should be around the 3-4hp mark. You might still get a CEL though.

Does the akra dp fit on RHD without modification though?

[pcockley]

Originally Posted by dh58

OOoooo do you know when this will be out?

Well Skycat what do you say?!

[mcmn]

Gents,

I personally installed my AR DP's on my own, with jackstands in my driveway. It ain't an easy DIY, and for the 500 odd bucks to get it professionally done I'd have to recommend going down that path. If there is any budding cheap arse in sydney let me tell you its not fun.

I agree with the comments about removing the cats from the stock dps. it's counter productive to an ability to go back to stock. Remember, if you dont have a tune that autodeletes the codes, you're car is going to light up like an xmas tree on tune removal. Essentially by removing the cats you ruin your ability to go back to stock.

[sparoz]

Originally Posted by dh58

Hmmm, never heard of akra. So if the diameter is higher than 2.5" you will lose HP?

So what is the point of having down pipes then? Just to have them remove the cat?

OOoooo do you know when this will be out?

Where have you been for the last 2 weeks - the most anticipated exhaust and dp release for the 1M. Akrapovic . Expensive exhaust, but the DP is very reasonable.

http://www.1addicts.com/forums/showthread.php?t=617056

I have no confirmed data with the sizing of the tube and its effects of power. However, the accepted effect is you have less power down low and gain it at the top end if you go for a larger size. Also, the stated rationale from one of the tunings for the 1M is that we don't need 3" unless you are looking to upgrade your turbo at a later date.

The point of dp is to gain hp, by removing the cats, to have a less restricted flow. Stock dp has 40-50% flow, catless is 100% and a 100 cell high flow cat is 95% flow. HJS makes a 90% flow euro 5 compliant cat as well, but each cat alone is > $500 US and 100 Cell ones are > $700 per cat.