Hello Scotty and Forum Members,
I am considering buying a 2017 BMW M240i. I have been looking into tuning options if I were to buy the car. The modifications I have looked into doing are flash tunes, piggyback tunes, cold air intake, and down pipe. If I bought the car I would aim to get around 500-525whp or 550-575hp at the crank without a meth injection and all of this with a stock engine and turbo all with bolt on mods. Also, how does tuning this engine affect the reliability of the car? Also does your MPG go down with tuning? Thanks for the help!
*Also, I want these results on pump gas not ethanol, or race gas.
@bclaud8977 Thanks for the kind words. I hope I can help answer some of your questions/concerns about tuning your BMW.
First, let me explain why tuning the car would shorten the lifespan. This is with any car out there: the vehicle is set up from the factory to offer the best balance of power, MPG, and longevity possible. Millions of dollars worth of R&D go into figuring out the right combination. When you modify a car by adding parts or tuning, or both, you are asking the engine to produce more power. This causes additional stress on the motor, as well as the transmission, rear differential, and all other components that have to deal with the added horsepower and torque. As such, the motor (and in your case, the turbos) will have a shorter lifespan as they are working exponentially harder than they were designed to. This is why building your car properly to handle the power is important, and also expensive. You have the car guy's triangle: cheap, fast, and reliable. You can have any two at the cost of the third. Your MPG will definitely see a significant decrease as well as you'll need to be pumping more fuel through the motor to make the power you want.
The second thing I can tell you is this: stay away from any canned tunes. If you want to have a reliable tune, you HAVE to have a dyno tune for your specific vehicle. You do not want something that's "close enough" or not personalized for your vehicle. BMW's are picky to the extreme and you need someone with experience in tuning them.
Thirdly and lastly, I don't recommend shooting for the power levels you describe on a stock motor or trans. I understand the ZF 8 speed is stout, but literally everything can be broken. I have significant concerns about trying to get the power levels you want out of a stock motor on pump gas. Even on premium pump gas, you would be pushing that engine HARD to get those numbers. @kesterpaul62 mentioned that you would be spending a couple of thousand rebuilding the motor and transmission if something goes wrong. He is being extremely nice with that statement. You'll be north of $10k on just those two components if they need replacement. Rebuilding is extremely complex to put it simple and not many places will even try on BMW hardware.
I understand your desire to get more out of your car. However, realize that BMW has tuned it for the best blend of power, longevity, and MPG. BMW's, Merc's, etc. are a whole different ball game than American vehicles. They already get impressive power from the displacement that they have. Pushing them further than stock requires deep pockets and the willingness to sacrifice reliability for performance. If you are daily driving the car, or it is your only transportation, I would strongly recommend against tinkering with it. If it is a weekend toy or project that you can live without if something breaks, that might be ok depending on whether or not you want to dedicate the funds to repair it each time there is a hiccup.
Hopefully I have helped somewhat.
Thank you! What power levels do you think would be still reliable in this car and what mods do you recommend I get to get me to that power. Also, after reading on forums I have heard on stock internals, reliability starts to fall off after 500 whp. If I were to get a tune, who would you recommend I get it from? I plan to get a cold air intake, catless downpipe, and maybe a cooling package, so that the wear on my internals is decreased, and I may get more power. Are these modifications ok to do on the car, or will they also negatively affect reliability. Thanks again more being so helpful!
And also, I will probably replace the differential anyway. And I know that manufactures make their tune for a balance of reliablity, performance, ad mpg, but I have heard from many people that the BMW M240i was held back in power because it did not want to encroach on the M2 and other M cars. In fact it had more torque than the regular M2 and was as fast in a straight line as it was. I am trying to build the car as a daily driver that can come alive on track. Like this but for less money. https://www.youtube.com/watch?v=Y-QSQYNqU10
So you're going for a hybrid "daily driver - occasional track car" build.
I would say keep it under 475HP for best reliability. I think 450 would be a good goal in your case. And 450 on 93 pump gas should not be an issue with those mods. I'm not a fan of catless pipes as they smell terrible, are generally just loud with no tone, and create emissions headaches. Plus many shops won't install them as they are illegal. But that's your choice. To find a good tuner, I would look through the BMW forums and see what is recommended in your area. You're going to want someone who has experience with German cars, so not the local muscle car shop. Do not worry - Euro tuners are not hard to find. You just want to look at reviews, research them, and see what their reputation is like. Then go and tell them what you want to do, ask any questions you may have, etc. If you feel comfortable, go ahead with it. Not sure if this applies and I'm guessing you know this already, but I am obliged to say you will be voiding any warranty on the car by making these changes. You may be past the warranty period or not care and that's fine too. I'm just compelled to make a mention of it. I'm happy to help members here whenever possible. I appreciate you asking me about this because, as you know, I build and tune cars all the time and I do have extensive experience working on the German stuff.
Thank you, when you say 450-475hp are you talking about at the wheels or at the crank? Also, is there a big difference in performance difference between a high flow vs catless downpipe and what other bolt on mods would you recommend? Power is the part of the build I am most worried about just because of the reliability, but what coilovers do you recommend for a hydrid daily driver/track car that cost under $2000? You have been extremely helpful and just out of curiosity, where is your tuning shop?
There is not a big difference between high flow and catless. You're going to see the same numbers between the two with a good tune. Anyone who says otherwise is just being lazy and not giving you their best tune work. I would say 475 crank is about the limit. They are l, I think, around 386 stock correct? So you are adding a good amount there. I would do a good cold air intake, a high flow down pipe, and I'd also add a full catback exhaust. Dinan makes good parts for BMW....they even have some power packages you can purchase depending on how much power you want to make. They are pricey, but you'll find that good performance parts for all German brands will be expensive. Don't cheap out though. I had a kid bring me a 335xi coupe he had chopped the exhaust up on and was running Flowmaster Super 40's. The whole car vibrated severely and the tone was awful. I wound up putting it back to stock for him to stop the migraines he was literally getting from driving it over any distance. Also, you mentioned possibly getting a cooling package. YES. Definitely do that. It will make a HUGE difference on your temps. My shop is down here in Houston. I sell classic cars, performance cars, and exotics. I also tune for all the above. I love my job after working so many years for others. Nice to be your own boss and also be able to do what you love to do. A lot of work and long hours, but I can't complain. Oh, and as for coilovers, I recommend Bilstein. But for price, I think Tein has some good options as well. Those would be my first two choices.
Thank you for your help! The M240i is rated at 335 stock but some people say the engines are underrated. Another question, would a High pressure fuel pump be worth it on this car on pump gas? Also, I am looking at the b16 by blisten, if you were getting the Blistein suspension, would you get it with damptronic or not damptronic? Damptronic is basically is an adaptive suspension option. Also, would you upgrade the brakes, if so just rotors and pads, or would you get a Big Brake Kit? Also, what are some other handling mods would you recommend? Bracing, anti-roll bars, poly or steel bushing and mounts, control arms, etc? Lastly, what do think is the best LSD I should get for the car, best overall, and best budget option? Thank you again for all of your help!
A HPFP would likely be worth it with the mods you have planned for it. For just like the occasional track day, coil overs, some anti-sway bars, and poly bushings should be fine. You don't want to go over the top as it is still going to be a driver. I wouldn't change the control arms unless you still aren't happy after doing the more inexpensive mods first. Start out simple, then adjust as needed is the best plan of action and the best way to keep more money in your wallet. Big brake kits are extremely expensive....unless you plan on spending whole days at the track, I'd just get a good set of pads and rotors. I'd probably go damptronic on the suspension so you can adjust it for track vs street use. If you were only going to use it for one or the other, you could skip it. As for the LSD, I'd recommend looking at Wavetrac's offerings. They are a little pricey but they are a quality unit without breaking the $1000 pricepoint. As always, I'm happy to help. Also, for handling mods, don't forget that tires make a big difference. I like Pirelli's options but that's 100% up to you.
Are there any mods that could make the car more reliable? I was also wondering if a vargas gc turbo for the b58 is worth it? It supposedly uses the stock turbo internals. I would probably use michelin ps4s's just because they seem to be a good blend of track and street performance.
Anytime you modify a car for speed, reliability slips. That's just how it goes. The cooling mods will help you get the most possible life, but it will still be shortened. That is why I don't recommend tracking your daily driver, but to each their own. I personally would not start fiddling with the turbos, especially with stock engine internals. I think it would be more headache than it is worth and again, you would be modifying another component and reliability would be sacrificed. PS4's would be a good choice in tire for your application.
BMWs cost a lot of money in terms of maintenance. Tuning a car like that will affect the reliability- big time. The engine and transmission will be exhausted and worn out already. You'd end up spending thousands of dollars in terms of modifying the car and then another couple thousand dollars rebuilding the engine or transmission or both.
This BMW is the most reliable car in their line-up. It uses the same engine, the B58 and transmission the ZF 8 HP that scotty raves about, is in the 2020 Toyota Supra. It is a closed deck design, and uses a diesel block. It is an extremely robust engine, that has been tuned to over 1000 hp on stock internals.
Also, the transmission in the car has been used in cars with over 600 hp, so I would think the transmission would be fine.
However, if you do plan on racing (don't know if you are) with all those mods, you will put more wear on the car. The ZF 8-speed transmission is a good transmission; but if you drive crazy, it will put more wear and tare on the transmission. Even good parts on a vehicle will wear out if you drive like that.
I believe @Mod_Man would know a ton about this as I believe he is a tuner himself. Hopefully he can come on here and give me some advice.
B58 is known to be built really well since it has a closed deck design and stronger components which can help take more power. If u have extra money around for the tuning and repairing the thing, go ahead but don't expect it to last as long as a stock B58.
I guess part of my question is how much reliability is lost through tuning this car. How much longer of a life would the stock car have than a tuned one. And why would the tuned car not last as long.