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Technical Topics B48 4-Cylinder Turbo Engine / Drivetrain / Exhaust Modifications [B46] Bootmod3 Stage 1 w/ 93 Octane on G20 First Impressions

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      01-07-2020, 03:58 AM   #67
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Quote:
Originally Posted by A6bullet View Post
No i mean youre right, and thats my concern too. Sure the B46 is a great engine, but a B48 with upgraded internals would definitely make me sleep better at night.
Like you said, if the internals had to be upgraded when pushing 300+ then maybe this needs more research? Maybe there are some weaknesses to the stock B46 parts, maybe just lower quality parts.

IDK, maybe Im just being paranoid.
There is no doubt that the crank, pistons and bearing(s) in the 330i are weaker / lower rated in regards to what HP and TQ they can handle as opposed to the other models with the same engine but with more robust internals that are pushing 300+ HP and TQ from factory. This is stated by BMW and I don’t think is up for debate. The question is, which I am not sure any 3rd party can answer at this point, can the 330i run at 300+ HP and TQ safely for many years to come, with minimal additional wear and tear, with only a remap. In my humble opinion, BMW doesn’t seem to think so or why would they spend the extra money to upgrade the 300+ HP and TQ B4s from factory.
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      01-07-2020, 07:26 AM   #68
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All manufacturers (at least in theory) should tune their engines conservatively so that there is ample margin for extra power left untapped. My assumption is that to have that margin of safety for the B48 they had to upgrade internals as a stage 1 tune on the B48 would bring 360 hp, close to or just over 400 tq. I can't imagine a stage 1 tune would impact this engine negatively if cared for properly. I'm personally waiting until the warranty has expired so i guess i'll have some time to let you guys be the guinea pigs.
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      01-07-2020, 09:06 AM   #69
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Quote:
Originally Posted by bquatt View Post
All manufacturers (at least in theory) should tune their engines conservatively so that there is ample margin for extra power left untapped. My assumption is that to have that margin of safety for the B48 they had to upgrade internals as a stage 1 tune on the B48 would bring 360 hp, close to or just over 400 tq. I can't imagine a stage 1 tune would impact this engine negatively if cared for properly. I'm personally waiting until the warranty has expired so i guess i'll have some time to let you guys be the guinea pigs.
I agree, they tune them with a margin of error, no doubt.

I guess the reality is until we have a few years, and a significantly large enough sample size of B4 330i’s running 300+ HP and TQ with only a small percentage failing, it’s simply a guessing game. Not an expert on exactly how internals fail, but I assume a crank, piston and bearing(s) could look in great condition (if the engine was opened up and disassembled) after 5,000 miles but on mile 5,001 it fails because it was never intended to run at 300+ HP and TQ?

I would imagine BMW has performed actual tests on internal components and knows details on what HP and TQ figures would lead to short term (5 years or less) engine failure, but unless someone has an inside connection only time will tell. Not sure I am prepared to be a test subject when it could be a $15k bill if the test fails.
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      01-07-2020, 09:45 AM   #70
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Damn, so I guess int he mean time, should this sub forum even be called B48 4-Cylinder Turbo Engine / Drivetrain / Exhaust Modifications?

This is one of the most disappointing things I've read all week.
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      01-07-2020, 10:01 AM   #71
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Quote:
Originally Posted by A6bullet View Post
Damn, so I guess int he mean time, should this sub forum even be called B48 4-Cylinder Turbo Engine / Drivetrain / Exhaust Modifications?

This is one of the most disappointing things I've read all week.
Interesting question, USA spec 330i’s are B46TU, but it seems like non-USA spec 330i’s also share the exact same internals as the USA, only a mapping difference for emissions and mpg requirements. Question is, is the B46TU still considered a B48 engine? Does it even matter? Seems like the only thing that matters is that the 330i, USA spec or not, has a weaker engine than certain B48 engines that BMW and Mini uses in 300+ HP and TQ cars from factory.

Last edited by Razor2010; 01-07-2020 at 10:20 AM..
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      01-07-2020, 10:44 AM   #72
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Yes sir. Mine is a MY2020 330i xDrive manufactured in 08/19 with a B46D engine. From my very limited knowledge, USA gets the B46D engine whereas the RoW gets the B48?

And IDK if anyone else with a 2020 330i in America has tried flashing their car. If so, they haven’t posted in any forum (other than g20beam but his is a 2019 in Canada). I tried flashing mine twice and failed. I’ve returned my BM3 map (the map I chose was for the B48 engine since that’s what others bought and I thought my car had the B48 engine). But after my car refused to start, I chickened out. I, like bquatt, am waiting for someone else with a 2020 NA B46 330i to flash theirs from PTF and only then will I go down that road again.

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      01-07-2020, 11:03 AM   #73
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Originally Posted by VipinLJ View Post
Yes sir. Mine is a MY2020 330i xDrive manufactured in 08/19 with a B46D engine. From my very limited knowledge, USA gets the B46D engine whereas the RoW gets the B48?

I have no idea, but I don't think this matters as it seems the internals are exactly the same for the 330i USA or non-USA / ROW 330i's.

My understanding is all 330i's are B46's now. See below link to an actual BMW technical training document.

https://f30.bimmerpost.com/forums/at...9&d=1553708460
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      01-07-2020, 11:05 AM   #74
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Quote:
Originally Posted by Razor2010 View Post
I have no idea, but I don't think this matters as it seems the internals are exactly the same for the 330i USA or non-USA / ROW 330i's.

My understanding is all 330i's are B46's now. See below link to an actual BMW technical training document.

https://f30.bimmerpost.com/forums/at...9&d=1553708460
If the internals are the same, I don’t mind the “lower” 46 number I was wondering if that was why my flash tune failed. Because I chose the B48 map and not B46.
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      01-07-2020, 11:34 AM   #75
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So would i be correct in saying that the "new" B46 is the previous gen B48 from the F30 328i albeit with the modifications listed in the PDF that's been attached in this thread?
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      01-07-2020, 11:35 AM   #76
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Quote:
Originally Posted by VipinLJ View Post
If the internals are the same, I don’t mind the “lower” 46 number I was wondering if that was why my flash tune failed. Because I chose the B48 map and not B46.
I would guess yes, in regards to why your flash didn't work, you chose the wrong engine.

The internals of the B46TU and B48TU are different (read the document from the link I posted, takes less than 10 minutes and is very clear).

That technical document may be specific for BMW North America. I assume there is still a possibility that non-USA 330i's receive the 'old' B46 (non TU), that doesn't have certain changes because of the lower emission standards outside of the USA. But, does this make sense for BMW to make two different B46's? Probably not, and all 2020 BMW 330i's USA and non-USA are running on the new B46TU engine.

The B48TU with upgraded internals is installed for other BMW and Mini cars that run 300+ HP and 330+ TQ. They should have just thrown that B48TU in the 330i and rated it at 302 HP and 332 TQ from factory, but I guess that would be too close to the M340i's numbers to justify people spending the extra $14k or so, although the extra 2 cylinders counts for more than just the additional HP and TQ in terms of drive-ability, BUT, it comes with a weight increase which is another rabbit hole. The 330i may have been just about perfect with the B48TU, 302 HP and 332 TQ from factory with the lower weight than the M340i. Fun discussions.
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      01-07-2020, 11:48 AM   #77
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Quote:
Originally Posted by bquatt View Post
So would i be correct in saying that the "new" B46 is the previous gen B48 from the F30 328i albeit with the modifications listed in the PDF that's been attached in this thread?
I think so, for the USA at least. The B46TU and B48TU have a start of production of 11/2018. I assume this would be too late to install in the first G20 330i's? I would guess that the first 2019 G20 330i's had the B46 (which use to be to be the B48 that was installed in the F30 330i in countries outside of the USA before 2019, but with some changes to bump up to the 255 HP and 295 TQ in the 330i G20). Then they phased in the B46TU in the USA with same HP and TQ but with emission standards that were required moving forward for the USA.

Lots of speculation still in regards to USA vs. non-USA
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      01-07-2020, 12:02 PM   #78
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They definitely made some efficiencies within the engine in the TU, that on paper, sound great. Whether or not they come at the cost of decreased durability is yet to be known

First world problems, i guess
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      01-07-2020, 12:29 PM   #79
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Quote:
Originally Posted by bquatt View Post
They definitely made some efficiencies within the engine in the TU, that on paper, sound great. Whether or not they come at the cost of decreased durability is yet to be known

First world problems, i guess
Hold your horses, the B48tu has exactly the same internals and compression ratio as both m340i and supra. They are tuning them B58TUs with stock internals over 200hp/l. If youre about to tune your engine i would suggest you go for a high spec 0w40 or 5w40 and do your changes after half the recommended interval. But at 150hp/l i wouldnt be worried.
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      01-07-2020, 12:46 PM   #80
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Quote:
Originally Posted by sspdw View Post
Hold your horses, the B48tu has exactly the same internals and compression ratio as both m340i and supra. They are tuning them B58TUs with stock internals over 200hp/l. If youre about to tune your engine i would suggest you go for a high spec 0w40 or 5w40 and do your changes after half the recommended interval. But at 150hp/l i wouldnt be worried.
Yes, but the USA G20 330i (and probably the global G20 330i) comes with the B46TU / B46 which does NOT have the same internals as the B58TUs. That would be the B48TU / B48 that has the upgraded crank, pistons and bearing(s). But you are correct, it does share the same compression ratio at 10.2:1. They dropped it from 11:1 to 10.2:1 from the B58 to the B58TU for the M340i and increased the boost to achieve the significantly higher HP and TQ over the previous B58 / 340i.

Am I wrong here or are the internals of the B46TU and B58TU the same (outside of the extra litre in size), and the B48TU actually has stronger internals than the B58TU? Honest question.
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      01-07-2020, 01:25 PM   #81
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Quote:
Originally Posted by Razor2010 View Post
Yes, but the USA G20 330i (and probably the global G20 330i) comes with the B46TU / B46 which does NOT have the same internals as the B58TUs. That would be the B48TU / B48 that has the upgraded crank, pistons and bearing(s). But you are correct, it does share the same compression ratio at 10.2:1. They dropped it from 11:1 to 10.2:1 from the B58 to the B58TU for the M340i and increased the boost to achieve the significantly higher HP and TQ over the previous B58 / 340i.

Am I wrong here or are the internals of the B46TU and B58TU the same (outside of the extra litre in size), and the B48TU actually has stronger internals than the B58TU? Honest question.
You are referring to the B48A20T1 found in x2 35i and m135/m235i, and yes it seems to have more solid internals than B58TU. Though i would think this engine is developed to acheive up to 400hp in later configurations. The B48/46B20O1 has got a forged crankshaft and many technical updates as to the old B48.
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      01-07-2020, 01:40 PM   #82
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Quote:
Originally Posted by sspdw View Post
You are referring to the B48A20T1 found in x2 35i and m135/m235i, and yes it seems to have more solid internals than B58TU. Though i would think this engine is developed to acheive up to 400hp in later configurations. The B48/46B20O1 has got a forged crankshaft and many technical updates as to the old B48.
Unfortunately, I think this is incorrect. The B48 has the upgraded crank, pistons and bearing(s). The B46 / B46TU does not. Scroll back through this thread and you will see a post where I provided links to this and also read that technical training document that I posted that also states the same.

I guess there is a possibility that the B46TU has the same internals as the B58TU but different to the B48TU. I would find this odd though. You bump up the HP and TQ significantly from the B58 to the B58TU but fail to upgrade the internals (crank, pistons and bearing(s)) of the B58TU and keep them as-is on the B46TU. Anything is possible I guess. But again, the fact remains that as per BMW, 100% the internals are in regards to the crank, pistons and bearing(s) different between the B46TU and the B48TU.

Last edited by Razor2010; 01-07-2020 at 01:49 PM..
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      01-07-2020, 01:54 PM   #83
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Where is a BMW engineer when you need one?
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      01-07-2020, 01:55 PM   #84
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Quote:
Originally Posted by Razor2010 View Post
Unfortunately, I think this is incorrect. The B48 has the upgraded crank, pistons and bearing(s). The B46 / B46TU does not. Scroll back through this thread and you will see a post where I provided links to this and also read that technical training document that I posted that also states the same.

I guess there is a possibility that the B46TU has the same internals as the B58TU but different to the B48TU. I would find this odd though. You bump up the HP and TQ significantly from the B58 to the B58TU but fail to upgrade the internals (crank, pistons and bearing(s)) of the B48TU and keep them as-is on the B46TU. Anything is possible I guess. But again, the fact remains that as per BMW, 100% the internals are in regards to the crank, pistons and bearing(s) different between the B46TU and the B48TU.
I dont really get that document, it refers to B48TU as compression ratio 9,6:1 and output of 306hp but its only the m35i models thats equipped with that engine. Here in sweden my 330i has the B48B20 with 10,2:1 compression ratio. And checking the internals compared to B58TU my engine is using exactly the same internals.
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      01-07-2020, 01:57 PM   #85
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Where is a BMW engineer when you need one?
LOL, for real
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      01-07-2020, 02:02 PM   #86
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I like the idea of a lighter crankshaft and single part timing chain that's apparently updated within the B46TU. The cooling system is apparently similar to one of their twin-turbo V8s. All of this speculation aside, the B46TU is a very advanced engine.
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      01-07-2020, 02:17 PM   #87
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Quote:
Originally Posted by sspdw View Post
I dont really get that document, it refers to B48TU as compression ratio 9,6:1 and output of 306hp but its only the m35i models thats equipped with that engine. Here in sweden my 330i has the B48B20 with 10,2:1 compression ratio. And checking the internals compared to B58TU my engine is using exactly the same internals.
I think part of the confusion is that document is for BMW North America. Maybe outside of NA the BMW G series 330i is made with the B48TU?

Couple of questions for you:

- Is your 330i the new G series, or old F?
- What is your manufactured date?
- How do you know that your engine internals are the same as the B58TU?

Thank you, we are getting closer to answers.
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      01-07-2020, 02:22 PM   #88
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Quote:
Originally Posted by bquatt View Post
I like the idea of a lighter crankshaft and single part timing chain that's apparently updated within the B46TU. The cooling system is apparently similar to one of their twin-turbo V8s. All of this speculation aside, the B46TU is a very advanced engine.
Sounds good, but does not change the fact that certain internals on the B48TU are stronger which is a shame.

It's like the 320i guys that are increasing boost etc. to achieve similar HP and TQ to a stock 330i, I think for the most part the 320i engine is similar internally to the 330i. That makes sense because the 330i comes at the 320i modded levels from factory. The problem is, the 330i may be maxed out and to go further we need B48TU internals.
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