[j2dad5389]

I'm currently running stage 1 bm3 with vrsf charge pipe and intercooler (just to be safe) and was thinking about getting downpipes so I can go stage 2. My concern is I'm not sure how much power these cars can handle and I don't really want to push it to its limits. Unless of course, it is more than capable of doing so, but I'm not sure. Stage 1 feels good but still, there is some desire for more power.

[gosi]

Tuning a car is pushing its limits... If you don’t want to do that you need to buy a more powerful car to begin with.

[Throttlesteer14]

There are plenty of people running that combo and the power shouldn't be pushing the upper limit of the motor. Keep searching the forums for people with similar setups and you'll probably find what you're looking for. I haven't seen any posts related to blown motors from a BM3 stage 2 and dp. But, there certainly is an increased risk as you push more boost and power.

[cooolone2]

Tuning is all about "knock"... And modding is all about realizing the most a given engine/drivetrain may offer.

As long as you realistically support your tuning with mods that will eliminate knock, or vice/versa, you'll be good!

Problems occur when limits are pushed beyond tolerance, such as fueling, etc., that an ECU cannot adjust for, ie, too much air, creating lean condition when fueling can't adjust.

With a Stage II tune, you're nowhere near the danger zone unless you try it without supporting mods! And really, if you're worried about breaking something, why are you modding?

Simple rule! You gotta pay to play...

Fast/Reliable/Cheap

Place your finger over the one you want, the remaining two is what you'll "NOT" get...

Fast isn't reliable or cheap
Reliable isn't fast or cheap
Cheap isn't fast or reliable



This is a universal law for hot rodding, lol

[dradernh]

Originally Posted by j2dad5389

My concern is I'm not sure how much power these cars can handle and I don't really want to push it to its limits.

I recommend continuing to research this subject and then looking for someone local (or within acceptable driving distance) who you feel comfortable working with and who doesn't start off telling you the big numbers they can produce for you. Those shops are best avoided when reliability is a concern. An outfit that specializes in BMWs, has a track record, and is willing to provide you with bonafide and relevant referrals is ideal. Take your time.

Generally speaking, for performance cars that are taken to the track the order of importance of the relevant factors is this: reliability, performance, mileage. Cost doesn't usually come up until the end of the conversation. That list holds for most street performance cars, too. Of course, there are exceptions: e.g., street racers, dyno queens, street cars that aren't driven much and are optimized for the strip, and other unusual cases.

As always, my 2¢.

[The_otherM235i]

To be completely fair, I find it sort of humorous when people ask if just throwing a few bolt ons to a N55 will hurt it, the answers no.

Will you put additional stress on every single part? Yes, but our N55s can handle way more then what you think. Our cars biggest downfall is the low performance turbo it has. Once you start throwing a bigger turbo at it with 500 wheel plus is when you start to push the boundaries of what the N55 is completely able to do. You won't see anymore than 390 wheel with a fbo stage 2 M235i. Custom tunes may push it a bit further but to be fair simply throwing a few bolt ons at the car isn't going to do anything to harm the reliability. Beat the piss out of it. I think what would hurt our engines the most is not warming it up properly when people start throwing boost at it. Watch your temps and you'll be singing all day long with a N55

[Dylan86]

Originally Posted by cooolone2

Fast/Reliable/Cheap

Place your finger over the one you want, the remaining two is what you'll "NOT" get...

Fast isn't reliable or cheap
Reliable isn't fast or cheap
Cheap isn't fast or reliable



This is a universal law for hot rodding, lol

I like the pick two, out of the three option..

Fast & Reliable sure isn't gonna be "cheap"
Reliable & Cheap sure won't be "fast"
Cheap & Fast most definitely will NOT be "reliable"

[j2dad5389]

Originally Posted by The_otherM235i

To be completely fair, I find it sort of humorous when people ask if just throwing a few bolt ons to a N55 will hurt it, the answers no.

Will you put additional stress on every single part? Yes, but our N55s can handle way more then what you think. Our cars biggest downfall is the low performance turbo it has. Once you start throwing a bigger turbo at it with 500 wheel plus is when you start to push the boundaries of what the N55 is completely able to do. You won't see anymore than 390 wheel with a fbo stage 2 M235i. Custom tunes may push it a bit further but to be fair simply throwing a few bolt ons at the car isn't going to do anything to harm the reliability. Beat the piss out of it. I think what would hurt our engines the most is not warming it up properly when people start throwing boost at it. Watch your temps and you'll be singing all day long with a N55

love this. thanks man. downpipes ordered

[Throttlesteer14]

You're getting more than one???

[BimBimM2]

Originally Posted by Throttlesteer14

You're getting more than one???

Maybe he really REALLY adores downpipes? It is 2020 man, to each their own.

[j2dad5389]

Originally Posted by Throttlesteer14

You're getting more than one???

haha autocorrect added an s for some reason. just the one. I got vrsf catless

[mike@x-ph.com]

Originally Posted by j2dad5389

I'm currently running stage 1 bm3 with vrsf charge pipe and intercooler (just to be safe) and was thinking about getting downpipes so I can go stage 2. My concern is I'm not sure how much power these cars can handle and I don't really want to push it to its limits. Unless of course, it is more than capable of doing so, but I'm not sure. Stage 1 feels good but still, there is some desire for more power.

the car will handle the power fine, its well within its limits. You can datalog and check it yourself or send your logs to your tuner for their opinion.

Off the shelf, maps leave a lot of power on the table with all their stages

[j2dad5389]

Originally Posted by mike@x-ph.com

the car will handle the power fine, its well within its limits. You can datalog and check it yourself or send your logs to your tuner for their opinion.

Off the shelf, maps leave a lot of power on the table with all their stages

Thanks, Mike. in your opinion, do you think I'm going to have a lot of drone or raspiness with the install of the downpipe? My friend raised this concern to me who has it on his and says it's bad. But then again he's not on stock exhaust and I am.

[mike@x-ph.com]

Originally Posted by j2dad5389

Thanks, Mike. in your opinion, do you think I'm going to have a lot of drone or raspiness with the install of the downpipe? My friend raised this concern to me who has it on his and says it's bad. But then again he's not on stock exhaust and I am.

You won't have any issues on the stock exhaust as long as you pick a downpipe that fits well

[j2dad5389]

Originally Posted by mike@x-ph.com

You won't have any issues on the stock exhaust as long as you pick a downpipe that fits well

I picked the vrsf catless (sorry!! I know how passionate you are about the evolution racewerks DP)

[XutvJet]

Some background first. The N55 in the M235 is unique compared to the N55s used in other BMWs. The crank is forged and is the same one used in the M2. Other N55s use cast cranks. It uses the same forged rods and rod bearings as the used in motor used in the M2/3/4. This holds true for all N55s beginning in 2014 as well. The M235 N55 uses more robust oil cooling so oil cooling isn't as issue. The M235 uses a far superior electronic waste gate (EWG) controlled turbo which is also a larger turbo. All 2014+ N55s use EWGs and the larger turbo. N55s prior had pneumatic waste gates and smaller turbos thus those motors made less power (stock and modded) and couldn't breath past 5500rpms. The 2014+ N55 makes peak power at ~6200rpms and can breath to 6600rpms before power drops off substantially. That's a huge difference in terms of sustained power, especially in 70+mph acceleration.

The M235's block, crank, rods, and bearings are capable of handling a good bit more power than stock. BUT there's a lot more to engine longevity than just those parts. The fuel system is only able to reliably sustain about 400whp before it becomes taxed. The spark plugs will wear out much faster. There will be a lot more stress on the coil packs. The transmissions (auto or 6MT) and cooling system, including the intercooler, were not intended to handle 20+% more power/torque in the long term. With more power comes a ton more heat. That heat degrades things thus parts will wear out more quickly. More boost and heat equals a much higher risk of the charge pipe failing.

Most importantly though, when you add more power, boost, timing, etc., the DME is operating outside of it's designed safeguards. Yes, they still work, BUT, the window between safe and dangerous operating conditions becomes MUCH narrower. Meaning, with a lot more power comes the risk a very dangerous knock events which could be disastrous and could cause a spun rod bearing, cranked ringland, burned piston/valve, etc.

A catted or catless DP will reduce exhaust gas temps and stress on the turbo. Less boost will be needed to make power. The reduced exhaust gas temps will somewhat reduce under hood temps.

380whp/420wtq is the reliable limit of the M235 N55, IMO. Even then, maintenance will increase and you open a larger window to failures, dangerous "super knock" events, etc. vs running stock.

All said, there is no certainty about "safe" when you starting modding an N55 or any motor for that matter. One also has to consider all the reasons why BMW went with a far stronger block, cooling system, etc. with the S55 which makes 410-430whp/420-440wtq stock which is hardly off what a Stage 2 EWG N55 can make.

[dradernh]

Originally Posted by XutvJet

All said, there is no certainty about "safe" when you starting modding an N55 or any motor for that matter.

This reminds me of a question I was first asked when having bike motors built in the 60s: "How many hours do you want it to last?"