[arketex]

Hello everyone I am new to forums in general and new to this one as well. I just wanted to get some wisdom from some people who have been there and done that. I have been a BMW enthusiast for a while now never really delving into modifications, but I worked in an import shop since high school so I have quite a decent understanding of how they function and how to maintain them. I have owned a variety of BMWs over my time mainly to purchase fix and flip, but I have enjoy my fair share. I am trying to settle down into a build that I can keep and I have settled on a 2010 BMW 335i E90 LCI. The car is clean with almost every option that could come with it. I got the car for a couple thousand due to it pouring out oil, but it is a clean car with 115k miles. I previously had an E92 which I flipped, but the lack of space from the coupe was not practical for me. I have done all the maintenance on the car that I have needed to. I do all my own work, so I just fix things as they pop up and do a little extra.

In my quest of perfecting the car, I want to go ahead and do an engine rebuild due to my valve seals leaking and the possibility of the rod bearings failing. I want to figure out what is the best course of action to build this car to be a comfortable daily driver with lots of power while maintaining a stock feel. I just want to know what the best plan of action is and what I should be spending my money on to do things the right way. I currently have the car fully stock with just an aluminium charge pipe (no BOV) to replace the crappy plastic one.

I am planning of committing to full bolt-ons, but I am not sure of what I should be doing in terms of the engine rebuild as well as the turbos. What is the best bang for my buck and what do most people go with and have success with? I have seen the forums and videos and things, but it seems everything is a mixed bag. I just would like some general advice from anyone who would be willing to share their wisdom.

[CarAbuser]

A CSF intercooler, catless downpipes and whatever turbo from RB that support your power goals (RB also have stock equivalents). Then get a custom MHD tune from WedgePerformance.

That's all you need in terms of mods. Ignition and fuel pump upgrades may be needed if you have high power goals or want ethenol. You can leave all the anodised engine bling and magic air filters on the shelf.

[Jaronbwall]

"I want to go ahead and do an engine rebuild due to my valve seals leaking and the possibility of the rod bearings failing" - This is an expensive and time consuming statement my friend.

How do you know the rod bearings or valve seals are bad? If it's not broken don't fix. I'm at 119K miles, FBO, with various other mods and completed tons of maintenance. If your car had been thrashed that's one thing, but what you described sounds like mine. Clean, not modded to h**l, pretty well maintained, other than a few oil leaks... exactly where was the leak? Long story short don't pull a d**n engine and oil pane if you don't need too.

[arketex]

The valve seals are bad it blows white smoke at idle. There is also a slight rod knock noise, indicating the rod bearings are worn. It isn't very expensive nor time-consuming for me as I have done a multitude of these for other customers. I was more concerned with putting the right supporting mods in place to really make sure I am capitalizing on all the work I am doing.

[Jaronbwall]

Originally Posted by arketex

The valve seals are bad it blows white smoke at idle. There is also a slight rod knock noise, indicating the rod bearings are worn. It isn't very expensive nor time-consuming for me as I have done a multitude of these for other customers. I was more concerned with putting the right supporting mods in place to really make sure I am capitalizing on all the work I am doing.

Damn, if that's the case I'd focus on replacing every dang seal or gasket you can. It's so much easier with the motor out. If you're going stage2+ you don't need anything extra. Can't help you beyond that as I'm not single turbo BIG power guy. This platform isn't the best for drag racing.

[tisdrew]

I was after the same thing with my old e90. To be honest, if you're willing to give up top-end power, I'd say to keep the stock turbos or go with OEM replacements or stage 1s from Pure Turbos. It's a mixed bag between the other aftermarket twins (RB, VTT, MMP, DA, etc.); I'm not saying Pure is perfect or a saint but I think they're the best option based on anecdotal evidence. The oem turbofolds are too restrictive for higher boost and the back pressure ratio over 15 psi starts to go wild and will blow out seals and the excess heat will ruin the bearings and internal wastegates of these designs.

425whp/500+wtq @~14-17psi which I feel is a sweet-spot on these cars:
fuel: walboro 450, updated/upgraded ekp, new hpfp, index 12 injectors, e40 blend (or meth inj if you don't have E85)

engine mods: catless downpipes, chargepipe as you've done, upgraded inlets, 5" intercooler. The rest of the exhaust is purely for sound and flows enough for 700. OST tune is best bang for buck and should be enough, a custom tuner might not be worth the money to you on stock(ish) turbos.

Other mods for quality of life: CDV delete makes clutch feel great, get good tires -- run-flats ruin the ride, m3 cowl upgrade, m3 control arms front, replace your shocks with latest. Ensure your PCV system is up to date (new valve cover) and do the walnut blast to get her running right. 335is/550i clutch or xhp trans tune. If you have the "double bubble", you can swap the oem screen with a android tablet and control the car that way.

Optional depending on $$: M3 rear end swap or LSD upgrade and diff bolt-down brace with rear m3 control arms. If your car is auto, a trans cooler might be worthwhile. Metal coolant thermostat. Coming from JDM-land, upgrading the radiator just makes me feel better about it esp considering how old these e9x cars are getting.

Things to definitely skip: aftermarket coil kits -- you don't need it sub 500whp. It's hype. 7"/stepped intercooler, a lot of trimming/cutting that doesn't net gains unless you're spinning those little boys too fast. Relocated inlets -- these do add power and sound great but the relocation is a PITA. skip the outlet upgrade.

A single turbo build is the opposite of "bang for buck".

[AWD Addict]

I was looking for a balance of as much power as I could get while retaining effectively daily driver reliability. Generally, don't nickel and dime anything. Stay away from ebay crap, and spend your money on high quality components and installers. This level of mods does produce great power, but generally is also additive to keeping the machine healthy and happy, particularly reducing IATs and heatsoak, and reducing backpressure at the turbos.

In order:

1) Assure your fuel pumps, injectors, coils and plugs are fresh while still stock. This will save you lots of headaches and streamline trouble shooting.
2) Get the MHD license and run logs to diagnose anything on the stock system, pre-tuning. You'll need it for the mods anyways. This will help with #1 above.
3) check your plugs and see if any are fouled or smell like fuel. This is a classic issue with this platform.
4) If you need to or are considering replacing your oil pan gasket, consider replacing your rod bearings. Particularly in a car that was tuned or not optimally maintained, this is cheap insurance while you're under there already, and is becoming a bit more common of an issue.
5) Upgrade your charge pipe (check)
6) Upgrade your intercooler. I like VRSF because the 5.5" requires no cutting, but there are lots of great options out there.
7) Run catless downpipes. I'm running VRSF, but there are lots of good options out there. Consider upgrading the 02 sensors if they're on the older side while you're doing this.
8) Suspension upgrades can fit in anywhere above this, depending on what you're dealing with. I'd recommend jumping to coilovers, which are generally pretty cost effective and reliable on this car.


I believe mods after that start leading to less driving, and more problem solving/troubleshooting. YMMV

[lowrydr310]

Originally Posted by AWD Addict

I was looking for a balance of as much power as I could get while retaining effectively daily driver reliability. Generally, don't nickel and dime anything. Stay away from ebay crap, and spend your money on high quality components and installers. This level of mods does produce great power, but generally is also additive to keeping the machine healthy and happy, particularly reducing IATs and heatsoak, and reducing backpressure at the turbos.

In order:

1) Assure your fuel pumps, injectors, coils and plugs are fresh while still stock. This will save you lots of headaches and streamline trouble shooting.
2) Get the MHD license and run logs to diagnose anything on the stock system, pre-tuning. You'll need it for the mods anyways. This will help with #1 above.
3) check your plugs and see if any are fouled or smell like fuel. This is a classic issue with this platform.
4) If you need to or are considering replacing your oil pan gasket, consider replacing your rod bearings. Particularly in a car that was tuned or not optimally maintained, this is cheap insurance while you're under there already, and is becoming a bit more common of an issue.
5) Upgrade your charge pipe (check)
6) Upgrade your intercooler. I like VRSF because the 5.5" requires no cutting, but there are lots of great options out there.
7) Run catless downpipes. I'm running VRSF, but there are lots of good options out there. Consider upgrading the 02 sensors if they're on the older side while you're doing this.
8) Suspension upgrades can fit in anywhere above this, depending on what you're dealing with. I'd recommend jumping to coilovers, which are generally pretty cost effective and reliable on this car.


I believe mods after that start leading to less driving, and more problem solving/troubleshooting. YMMV

This is sound advice. Get the routine maintenance done before modifying anything.

I'm not new to the E9X but I did just recently get a E93 with the N54. I'm being reasonable with my expectations as I want to prioritize reliability (and emissions compliance, in other words convenience and not having to swap parts for inspections.) I did a suspension refresh and new tires recently, walnut blast, aluminum mickey mouse flange upgrade, new radiator hoses, new belts and tensioner, new idler pulleys, aluminum water pump pulley, new battery, new silicone vacuum hoses, and fresh coolant and oil changes.

Soon after doing that I was driving in 95° heat and my expansion tank started leaking at the seams so I am replacing that next along with coils and plugs. I also ordered new boost solenoids. I don't have MHD so I have no logging ability to know exact WGDC values however these are the original boost solenoids with over 150K miles and from what I'm reading that's well over their expected life.

Once I get that taken care of I need to ensure the car is running properly before flashing anything. I like the idea of getting the basic MHD monitor license before flashing any tunes, just to monitor everything and ensure there's a solid baseline. I'm a bit undecided because the super license is $60 more than separate monitor, flasher, and OTS maps pack, but I can't see myself ever needing the ethanol tunes or the high boost capabilities. My plan is just to add cone filters, upgraded charge pipe, and a 5" intercooler. Downpipes are out of the question for me. Another factor is the available fuel. 91 is the best I can get which is the biggest limitation to what I can do.