335i fuel, and tune

[JohnGoesZoom]

Hey everyone - first post after buying a 2008 335i sedan at 43k miles. Lady ran a light and completely totaled my LT camaro, so figured Id go ahead and get my dream car to replace it.

Only a couple questions! 91 octane is hard to come by in Texas, but found that if I mix 2 gallons of e85 with 7 gallons of regular 87, it comes out to 91 octane assuming that the e85 is 105 octane. This puts it at an e27 mix.

Is this safe to run without a tune, or will I be committing hpfp or injector suicide? And if not, which tune on the jb4(on the way) would assist with this? Dual cai on the way as well, and will probably order catless downpipes next, followed by aftermarket intercooler. That will most likely be the extent of my mods, as Im trying to make this car last as long as possible. I do 90% of my own maintenance, but don't have the equipment to pull an engine or do transmission work.

Also - if the girlfriend takes it out, can I just run 87 octane straight if I put the valet mode(girlfriend mode) on the jb4 with the wastegates open?

Absolutely correct me if Im wrong on any of this, Ive worked on my own vehicles my entire adult life(31 now), but this is my first turbo car. Love the boost, pretty sure it prevents erectile dysfunction.

[Hova]

Hey everyone - first post after buying a 2008 335i sedan at 43k miles. Lady ran a light and completely totaled my LT camaro, so figured Id go ahead and get my dream car to replace it.

Only a couple questions! 91 octane is hard to come by in Texas, but found that if I mix 2 gallons of e85 with 7 gallons of regular 87, it comes out to 91 octane assuming that the e85 is 105 octane. This puts it at an e27 mix.

Is this safe to run without a tune, or will I be committing hpfp or injector suicide? And if not, which tune on the jb4(on the way) would assist with this? Dual cai on the way as well, and will probably order catless downpipes next, followed by aftermarket intercooler. That will most likely be the extent of my mods, as Im trying to make this car last as long as possible. I do 90% of my own maintenance, but don't have the equipment to pull an engine or do transmission work.

Also - if the girlfriend takes it out, can I just run 87 octane straight if I put the valet mode(girlfriend mode) on the jb4 with the wastegates open?

Absolutely correct me if Im wrong on any of this, Ive worked on my own vehicles my entire adult life(31 now), but this is my first turbo car. Love the boost, pretty sure it prevents erectile dysfunction.

What are your goals?

Are you okay with a fast spooling 400whp? Anything above that on stock turbos is short lived. Get the VRSF downpipes, the cheap ones don't fit right an it's a major pain. Replace BOTH upper O2 sensors. Use the same sensor. The rear sensor is more expensive than the front, but just run two of the front sensors, and it will be fine. Coil the wire to the side or under the valve cover.

https://www.amazon.com/Bosch-17098-O.../dp/B000JZGEWE


Get a 7.5" Stepped Intercooler. It's worth the money to keep the intake temps cool. If you don't have the money for a stepped intercooler I have a non-stepped one I can sell you, 7.5".

For the love of God, do NOT buy an expensive blow off valve. It's so stupid. Unless you're into that kind of thing, then go for it. Absolute waste of money and time though. Cheap charge pipe and cheap blow off works just fine.

Don't buy intake pipes, they are a waste for the most part too. They MIGHT add 10-15hp? Not worth the $300+ asking price.


My last 335 made right at 700whp without meth, but I had to have the overdrive pump on my HPFP (high pressure fuel pump). Do NOT get a shotgun pump, complete garbage. You can run straight E85 with this at pretty high levels of power on stock turbos:

http://spoolperformance.us/index.php...&product_id=71

You will need to upgrade your LPFP (low pressure fuel pump), under the back seat, inside the fuel tank. You can do this a number of ways, some cheaper than others. Again, it has to do with how much power you want. Some are cheaper than others. If you plan on doing ethanol, plan accordingly. You shouldn't run E85 on the stock pump for long, it will fail eventually. I had dual pumps in the tank, but a single pump will worth for ~500whp.

Seriously, if you want to make high levels of reliable power, you should do a single turbo kit. Doc racing has theirs for $3,800. You can literally have 600-700whp for less than 5k. I've never seen another platform that can make that kind of power at this price point.

https://docrace.com/collections/black-friday-sale-1

The stock turbos are okay, I was (and still have) a FBO (full bolt on) 335 N54. I advise people against meth injection, it's a band-aid for a problem.

JB4 isn't the greatest. Just running MHD is a lot cleaner of an install and runs way nicer. The new MHD wifi adapter is the nicest integration I've seen. I have it running on a dedicated Galaxy S6 in my car and it's great.

Why are you putting your GF on valet mode? Is she reckless with your car? You should think that through into your future, people reckless with your stuff end up being reckless with you. No, you can't run 87 octane on your motor. Doing so WILL cause issues on a hot day. These motors run extremely hot already (I see oil temps of 240-250 all the time, and coolant temps of 220-230 on hot days), putting low octane gas in a high compression twin turbo car is literally asking for blowing your engine.

If you're an automatic I highly advise you go for the XHP tune. The stage 3 tune is incredible. The car becomes way faster and shifts almost like a DCT car, plus if well maintained (fluid changes and filter changes) you can hold 600tq+ on the automatic trans (which is nuts for a stock automatic).

I have had quite a few 335i's, if you have any questions feel free to ask.

[JohnGoesZoom]

Hey, I definitely appreciate such an informative reply.

I think you're right, I will go MHD instead.

Now, I really have relatively low horsepower goals initially - I'll do the first Stage 1 tune with the MHD, and add the BMS dual CAIs that just came in. I'm perfectly fine with 380whp until other parts begin to fail on the car, and I need to replace. Not planning on running it too hard, but I'd like to feel the back of the seat every so often. The LT camaro didn't quite do that for me. Eventually, if I need to replace a few things, I'll replace them with good quality parts, then I'll mod higher to about 450whp or Stage 2(not going to pretend like I fully understand the stages just yet). That's as far as I'll ever go with this car.

The whole "wreckless gf thing" is more so bad experiences with the one girlfriend I ever let drive my car, and you're absolutely right. She's probably rarely ever going to need to drive it, but what I was really wondering was that in valet mode, the turbos aren't active right? That would mean the engine isn't running at that high of a compression ratio, so I had thought that if the engine retards the timing to accommodate the lack of octane it would be fine since the turbos were deactivated? Isn't it basically an N/A engine at that point? Was just a theory, and with my limited knowledge about these turbos, theories can be quite dangerous lol.

Also, I believe I'll go ahead and get new Bosch coils and some 1 step colder plugs before I tune with MHD. Possibly clean the intakes too, Harbor Freight has a media blaster for like $30, along with walnut shell media in case the intakes are nasty, does anyone think this bad boy will get the job done well enough?

https://www.harborfreight.com/portab...kit-37025.html
https://www.harborfreight.com/25-lbs...dia-92150.html

[Hova]

Hey, I definitely appreciate such an informative reply.

I think you're right, I will go MHD instead.

Now, I really have relatively low horsepower goals initially - I'll do the first Stage 1 tune with the MHD, and add the BMS dual CAIs that just came in. I'm perfectly fine with 380whp until other parts begin to fail on the car, and I need to replace. Not planning on running it too hard, but I'd like to feel the back of the seat every so often. The LT camaro didn't quite do that for me. Eventually, if I need to replace a few things, I'll replace them with good quality parts, then I'll mod higher to about 450whp or Stage 2(not going to pretend like I fully understand the stages just yet). That's as far as I'll ever go with this car.

The whole "wreckless gf thing" is more so bad experiences with the one girlfriend I ever let drive my car, and you're absolutely right. She's probably rarely ever going to need to drive it, but what I was really wondering was that in valet mode, the turbos aren't active right? That would mean the engine isn't running at that high of a compression ratio, so I had thought that if the engine retards the timing to accommodate the lack of octane it would be fine since the turbos were deactivated? Isn't it basically an N/A engine at that point? Was just a theory, and with my limited knowledge about these turbos, theories can be quite dangerous lol.

Also, I believe I'll go ahead and get new Bosch coils and some 1 step colder plugs before I tune with MHD. Possibly clean the intakes too, Harbor Freight has a media blaster for like $30, along with walnut shell media in case the intakes are nasty, does anyone think this bad boy will get the job done well enough?

https://www.harborfreight.com/portab...kit-37025.html
https://www.harborfreight.com/25-lbs...dia-92150.html

I sell an abrasive kit. I use that exact blaster and walnut shells. You'll only use 3-5lbs of the walnut, but it's well worth doing. Make sure to get a set of o-rings for the intake manifold though, you'll need 6 of them. A new charge pipe o-ring would be wise to change as well.

https://www.e90post.com/forums/showthread.php?t=654820

Great tutorial. If you end up doing this and need help, reach out. More than happy to walk you through it.


Instead of the Bosch coil packs, buy the Delphi packs. 1 step colder plugs are a must. Stick with NGK or Bosch.


The turbos are always active, you can load a different tune and run with the wastegates open which will produce very little boost. You can run lower octane gas then I suppose. The N54 ECU is absolutely amazing though and the second it detects any knock it begins to retard timing. You can monitor real-time timing in JB4 and MHD and it's amazing to see how different temperature days change timing.

[pbonsalb]

I had to scrape out a lot of goo. The walnut shells are good for blasting the hard carbon that is under the hood. You can buy on eBay or maybe amazon the plastic intake fitting that you connect the vacuum to and that has a hole for the blasting wand and you can buy a wand as well if you don’t want to make one.

I bought the S55 coils. It was not long after installing the JB4 that the original coil packs began misfiring due to the higher boost levels. I am running stock plugs, but have only the JB4 for mods since it is the car my wife drives.

[JohnGoesZoom]

The turbos are always active, you can load a different tune and run with the wastegates open which will produce very little boost. You can run lower octane gas then I suppose. The N54 ECU is absolutely amazing though and the second it detects any knock it begins to retard timing. You can monitor real-time timing in JB4 and MHD and it's amazing to see how different temperature days change timing.

Sounds like it might work! If I ever did that, I'd definitely try my best to keep rpms under 3k.

Man, the more I read, the more I feel like I should get an oil cooler too. Definitely metal charge pipe with some sort of blow off valve(I don't care about the sound, I just want my car to last). I'm super tempted to install the bms dual cones, then flash MHD to stage 1, but know I should wait until I know a little more about the car. 43k miles, but the dealer didn't have any maintenance records for it - not sure if it has fresh plugs in it or not, but it isn't throwing codes.....yet.

Also saw a guy cleaning out the carbon for his intakes with CRC intake valve cleaner and it seemed to do pretty well. I'd be terrified to liquify all that carbon and have it leak into my engine, any experience with this? CRC valve cleaner vs Walnut Blasting?

BTW Hova - How much you selling that other intercooler for? PM me, I might be interested!

Thanks again everyone, I absolutely love this machine.