[tilua]

I have a stock 2008 335i convertible with 120K miles on the clock. I've done all the maintenance and repairs since i bought it 9 years or so ago. The maintenance and repair log i have on this car is longer than all of my other cars combined. This car is no longer my daily driver car due to its age and unreliability. I am looking to make this a toy/weekend/project car. So... I am looking to do some mod to improve its performance ( i hear ECU tune? intake/exhaust?) but not so much for cosmetic. Thanks for any advice.

[Spyro235]

There is just oodles of advice like this on the forum, probably even on the first page! Try looking for it, there is all the information you could possibly want to read on this exact question.

If it's unreliable enough to not be your daily, I'm not sure why you would mod it. I think you need to do some research into the common maintenance the n54 motor needs, and start chipping away at those. Do all the seals and gaskets... and then injectors to index 12, new coils and plugs. THEN you should start modding.

My n54 has 171k on it, and I'm reliably stage 2 tuned with MHD with catless downpipes installed. Just doing research on the worlds in the last sentence will give you enough information to read up for a day or two of your free time! Good luck!

[srey]

I agree with Spyro235. Do all the maintenance that will make the car reliable. It could be a fun project for you since it is not your daily driver anymore. If they're leaking, do the oil pan gasket, the OFHG, and the valve cover gasket. Do a walnut blast on the intake valves. Replace the silicone vacuum lines that control the wastegates. Replace the boost solenoids if necessary. New coils and plugs. Check to see if your injectors are leaking. If they're not, leave them be for now. After all of that, do catless downpipes, bigger intercooler, a chargepipe, and an MHD tune.

[tilua]

I appreciate the feedback. Of course I will take care of the maintenance issue before doing the tune. but the thinking is the car is aging and won't be as reliable, i dont mind letting it sit in the garage for days/week at a time. And if that is the case, i would be fund to mod and treat it as a toy car. I will look into all the potential issue that you've mentioned.

[xcusem3]

Please do not performance mod an n54 with 120k miles!!! You will blow something up within weeks of adding any boost to the car I guarantee it.

A cold air intake makes you hear the turbos spool up a little louder which is a good option, or a bigger intercooler if you drive your car somewhat aggressively at all in the summer months.

[srey]

Originally Posted by xcusem3

Please do not performance mod an n54 with 120k miles!!! You will blow something up within weeks of adding any boost to the car I guarantee it.

A cold air intake makes you hear the turbos spool up a little louder which is a good option, or a bigger intercooler if you drive your car somewhat aggressively at all in the summer months.

Lots of guys do performance mods to N54s with that mileage and higher. If you're up to date on the maintenance it won't be an issue. You are fear mongering. There isn't a magic mileage number after which an N54 car will explode. Condition and maintenance schedule is everything.

OP, go ahead and mod if you're up to date on all your maintenance.

[xcusem3]

Originally Posted by srey

Lots of guys do performance mods to N54s with that mileage and higher. If you're up to date on the maintenance it won't be an issue. You are fear mongering. There isn't a magic mileage number after which an N54 car will explode. Condition and maintenance schedule is everything.

OP, go ahead and mod if you're up to date on all your maintenance.

LOL it only happened to both of my 335's but okay don't say I didn't want you OP..

And yes I was up to date on all maintenance, it's the slow additional wear and tear that kill these cars with so many cheap plastic components under the hood it's inevitable really

[catcher22]

If you're up to date on maintenance, mod away! If I were you, I would start with an intake and a piggy back tune and/or Back End Flash.

Don't listen to the person above who says you can't mod these cars past 120k miles, that's completely ridiculous lol. Lots of folks here have that mileage, and more, and are FBO. Just be prepared for repair items and stay up to date on maintenance.

I'd actually argue that my car is more reliable in it's older age. Many of the stock components fail at early miles, and once fixed or replace should last a relatively long time.

OP-How many miles are on your N54?

[srey]

Originally Posted by xcusem3

LOL it only happened to both of my 335's but okay don't say I didn't want you OP..

And yes I was up to date on all maintenance, it's the slow additional wear and tear that kill these cars with so many cheap plastic components under the hood it's inevitable really

Your personal experience is still anecdotal. I didn't start modding my car until it had 115k miles. It has yet to explode. And even if it does, big deal. Like the OP, my car is not my only means of transportation. If something goes I can afford to let it sit in the garage while I take my time fixing it.

What specifically failed on your cars after you modded at high mileage?

[Spyro235]

Originally Posted by xcusem3

LOL it only happened to both of my 335's but okay don't say I didn't want you OP..

And yes I was up to date on all maintenance, it's the slow additional wear and tear that kill these cars with so many cheap plastic components under the hood it's inevitable really

I went stage 2 with catless DP's only, at about 130k miles. I'm at 171k now and it's been super reliable. Targets and hits 16psi all day if you ask it to. I'm on the original charge pipe too.

[xcusem3]

Originally Posted by srey

Your personal experience is still anecdotal. I didn't start modding my car until it had 115k miles. It has yet to explode. And even if it does, big deal. Like the OP, my car is not my only means of transportation. If something goes I can afford to let it sit in the garage while I take my time fixing it.

What specifically failed on your cars after you modded at high mileage?

I hear ya man, I do!

On my 07 the turbos failed, a piece of the impeller snapped off and did quite a number on my ETS 7" intercooler it has 124k mls and I added the Cobb tune at 112k mls

For my 09 I had leaking injectors which caused a ton of burbles/pops and stuff when I let off the throttle which sounded cool but one day too much fuel dumped through the block when I let off the gas after a nice acceleration run and it caused my new downpipes to fail which caused a negative vacuum effect to occur in the block and I ended up scraping all 6 cylinder walls and damaged the pistons...

So yeah that was the end of my 335 days lol

[xcusem3]

Originally Posted by Spyro235

I went stage 2 with catless DP's only, at about 130k miles. I'm at 171k now and it's been super reliable. Targets and hits 16psi all day if you ask it to. I'm on the original charge pipe too.

Lucky man! I was running 19 psi and maybe that was a little much but look at my post above to see what it did to both of my 335's

[srey]

Originally Posted by xcusem3

I hear ya man, I do!

On my 07 the turbos failed, a piece of the impeller snapped off and did quite a number on my ETS 7" intercooler it has 124k mls and I added the Cobb tune at 112k mls

For my 09 I had leaking injectors which caused a ton of burbles/pops and stuff when I let off the throttle which sounded cool but one day too much fuel dumped through the block when I let off the gas after a nice acceleration run and it caused my new downpipes to fail which caused a negative vacuum effect to occur in the block and I ended up scraping all 6 cylinder walls and damaged the pistons...

So yeah that was the end of my 335 days lol

Condolences. That sucks. I'm surprised your turbos failed that way. That's kind of a freak incident.

[tilua]

Originally Posted by catcher22

If you're up to date on maintenance, mod away! If I were you, I would start with an intake and a piggy back tune and/or Back End Flash.

Don't listen to the person above who says you can't mod these cars past 120k miles, that's completely ridiculous lol. Lots of folks here have that mileage, and more, and are FBO. Just be prepared for repair items and stay up to date on maintenance.

I'd actually argue that my car is more reliable in it's older age. Many of the stock components fail at early miles, and once fixed or replace should last a relatively long time.

OP-How many miles are on your N54?

I have 120K miles and have been hardly driven hard. BUt since it is now a project car. I intend to drive the $#!t out it

[Spyro235]

Originally Posted by xcusem3

Lucky man! I was running 19 psi and maybe that was a little much but look at my post above to see what it did to both of my 335's

The turbos... that’s just unfortunate. The leaky injector- that’s kind of you man. If you knew it was leaking, and kept pounding the motor... that’s not the motor’s fault.

One of the most important things to know when driving a car hard, is if you feel something isn’t right, get out of it and shut the motor off. Crazy misfires? Don’t hold the pedal through it. Know you have leaky injectors? I’d be worried about hydrolocking and would likely stop driving the car until it was swapped out. If anything feels not normal, stop!

[xcusem3]

Originally Posted by Spyro235

The turbos... that’s just unfortunate. The leaky injector- that’s kind of you man. If you knew it was leaking, and kept pounding the motor... that’s not the motor’s fault.

One of the most important things to know when driving a car hard, is if you feel something isn’t right, get out of it and shut the motor off. Crazy misfires? Don’t hold the pedal through it. Know you have leaky injectors? I’d be worried about hydrolocking and would likely stop driving the car until it was swapped out. If anything feels not normal, stop!

Yeah well a $5k repair bill for injectors and fuel rails on a car that's barely worth $10k is not my idea of regular maintenance. There were far too many issues with both of my 335's to reasonably recommend to a fellow enthusiast to mod his very high mileage car.

It's been over 3.5 years since I've been out of a 335 and driving my e92 m3 and I haven't had a single issue what so ever.. and it's been supercharged for almost 2 years now

[srey]

$5000 for injectors and a new fuel rail 4ish years ago? Sorry, man, but it sounds to me like you may have gotten taken for a ride by the shop. I don't know what injectors prices were in 2014, but i doubt it was enough to come out to $5k with labor. I'm sure there's more to the story.

[Bimmer_Engineer]

Originally Posted by xcusem3

Yeah well a $5k repair bill for injectors and fuel rails on a car that's barely worth $10k is not my idea of regular maintenance. There were far too many issues with both of my 335's to reasonably recommend to a fellow enthusiast to mod his very high mileage car.

It's been over 3.5 years since I've been out of a 335 and driving my e92 m3 and I haven't had a single issue what so ever.. and it's been supercharged for almost 2 years now

You have a supercharged M3? I don’t know much about them but that sounds pretty cool...can you post some pics?

[xcusem3]

Originally Posted by Bimmer_Engineer

You have a supercharged M3? I don’t know much about them but that sounds pretty cool...can you post some pics?

Sure do! It's actually quite common for the e92 m3, poke around on the m3 forums on here there's a ton of info on it

I'm running the VF 595 kit which is exactly what it sounds like, 595 crank hp and somewhere around 400ftlbs which yes I know is a little low in the n54/55 world but man is it fast!!

I'll try and post some pics if I can get it to work on my app.

[Silent9n54]

just go for it

i started modding mine at 100.000 miles now at 120+ been running e40 custom tune at 21.5 psi 441hp / 535tq... no major issues in a year with this tune

2007 E92 335i / VRSF 5" FMIC - Downpipes - Charge Pipe - DCI / TurboSmart Plumb Back DV / XHP Stage 3 / E40 Custom Tune by Wedge / APEX ARC8 / Michelin PS4S / 11.95 @ 116 / Instagram.com/silent11n54

[catcher22]

Originally Posted by xcusem3

Yeah well a $5k repair bill for injectors and fuel rails on a car that's barely worth $10k is not my idea of regular maintenance. There were far too many issues with both of my 335's to reasonably recommend to a fellow enthusiast to mod his very high mileage car.

It's been over 3.5 years since I've been out of a 335 and driving my e92 m3 and I haven't had a single issue what so ever.. and it's been supercharged for almost 2 years now

do you have the same license plate and are in Penrose? I park in B3 too.