[Alan l.]

Debating if i want to go with DP's for my N55 F10. Just not use to making so much less power compared to my N54 335 and want to close the gap with more performance mods.

I know for the N54 DP's are def. worth it because the gains with a tune is huge but what about the N55? Seems like dp's only give you 10-15hp and similar torque which doesn't seem like its worth the trouble to me.

Also, for the N54 users reported the car would feels strange during morning cold starts after they got downpipes. I suspect it has something to do with the O2 reading. Is there ANY cons when adding carless DP's on the N55?? Doesn't matter how big or small.

Thanks
Alan

[BGg30]

i would say the worst case would be voided warranty plus no real dp fix yet. i personally do nit have a dp yet because theres no dp fix yet

[FrankiE90]

DP will open up the N55 -
it's worth doing.
if u had catless DP on ur n54 - shouldn't be a question.
the smell is the downside for most.

i don't know how emissions testing is for you but
something to also consider.

[CombatNinja]

Potential downsides: constant CEL, cat efficiency codes stored, smog test hassles, warranty issues, unburnt fuel odors, and noise.

Upsides, quicker spoolup and more pow-ah.

[mashimarho]

None for me......

[PeterM]

I was thinking of getting a stock downpipe off ebay and hallowing out the cat part. Stock downpipe looks plenty big then i wouldn't really have to worry about warranty void as it will look factory. But then you gotta figure out a way to keep the CEL off, Have you guys tried a spacer on the rear O2 sensor or it doesn't work on the BMW's

[badblkX6]

I would advise against hollowing out a stock downpipe. I am not sure but I think I saw a thread on here somewhere where the person did that and they were getting a droning sound or something like that.

I would recommend buying the BMS downpipe because of the price, quality and customer service. I also believe that BMS just released their downpipe fix. There are probably a few threads about that. Just check around

You could also pair the downpipe with the BMS tune and it will remove the light from your dash and clear the codes. Plus those two mod combos work great together. You get more sound out of the stock exhaust and more performance with the tune.

Best of luck!

[Alan l.]

How bad is the smell?

So in terms of driveability theres no compromise at all even during cold starts etc..?

On the N54's people said during cold mornings the car would idle erratically with DP's because the ecu wasn't seeing what it wanted to see from the O2 sensors.

Alan

[1nityrider]

Originally Posted by BSe92

i would say the worst case would be voided warranty plus no real dp fix yet. i personally do nit have a dp yet because theres no dp fix yet

I am looking to buy a 335xi and have being doing my research since I know I will be doing BTUs. So all the dp fixes that I see from web sites that they sell don't work?

[CombatNinja]

The smell is very mild, only noticeable when idling in the garage or sometimes when reversing. Even then it is pretty tame. Worth mentioning because some people have different sensitivities to the smell of gasoline.

I have never experienced any erratic idle with a catless n55 downpipe.

[eyim1988]

Originally Posted by CombatNinja

The smell is very mild, only noticeable when idling in the garage or sometimes when reversing. Even then it is pretty tame. Worth mentioning because some people have different sensitivities to the smell of gasoline.

I have never experienced any erratic idle with a catless n55 downpipe.

Put in mixes of e85.. Smells sweet.

[daixloxbmw]

Originally Posted by badblk335i

I would advise against hollowing out a stock downpipe. I am not sure but I think I saw a thread on here somewhere where the person did that and they were getting a droning sound or something like that.

I would recommend buying the BMS downpipe because of the price, quality and customer service. I also believe that BMS just released their downpipe fix. There are probably a few threads about that. Just check around

You could also pair the downpipe with the BMS tune and it will remove the light from your dash and clear the codes. Plus those two mod combos work great together. You get more sound out of the stock exhaust and more performance with the tune.

Best of luck!

BMS has confirmed that their DP Fix does not work for the N55. It only works for the N20.

[Freelo]

Could someone please clarify if the CEL problem is only if you DO NOT already have a piggy back tune?

Don't both JB4 and Procede clear the CEL if you are running a tune? I thought this was the case. Thanks.

[Sara]

Originally Posted by mashimarho

None for me......

+1

[BMW_Belgier]

Originally Posted by Freelo

Could someone please clarify if the CEL problem is only if you DO NOT already have a piggy back tune?

Don't both JB4 and Procede clear the CEL if you are running a tune? I thought this was the case. Thanks.

The CEL problem is NOT yet solved for the N55 engine... Even the piggys just put it in clear. So not really solved like on the N54 engines... The DPfix of BMS was reported to not working. Another DPfix from a user on this board is being tested as we speak...

[SRT14PimPin07]

I was very "scared" to get a catless DP mainly due to it's smell. You might wana read my thread http://www.e90post.com/forums/showthread.php?t=731298

All in all, I do not regret getting it. The smell is literally less than a lawnmower. The power gains are defiantly noticeable. The smell only hits me if I come to a quick stop after some spirited driving

[bulldog_yyc]

Originally Posted by Alan l.

How bad is the smell?

So in terms of driveability theres no compromise at all even during cold starts etc..?

On the N54's people said during cold mornings the car would idle erratically with DP's because the ecu wasn't seeing what it wanted to see from the O2 sensors.

Alan

smell is an annoyance, specially if you park underground or covered lots. Cold starts are ok, slightly louder for a minute or so. Idle is not erratic at all.

Its a worthwhile mod and for the N55, one of the better mods to add power - I say go for it. I think AR has an F10 downpipe or the dr euro.

[hetzle]

Gains will be around the 20-30rwhp range with a tune, running one without a tune would be silly

[BMW_Belgier]

Originally Posted by hetzle

Gains will be around the 20-30rwhp range with a tune, running one without a tune would be silly

Why would it be silly?

It de-stresses the turbo so upgrading it's reliability! Power gain is rather small but stil there!

Silly it isn't...

[CombatNinja]

There are also benefits in reduced spool time even without a tune. It is not "silly" at all.

[hetzle]

Originally Posted by BMW_Belgier

Why would it be silly?

It de-stresses the turbo so upgrading it's reliability! Power gain is rather small but stil there!

Silly it isn't...

Because of all the associated errors? You'll need some sort of software (DP fix or tune) to take full advantage of it and eliminate drawbacks