[Joe_E]

What kind of power can the 328i tranny and n26 handle? Looking into doing a turbo upgrade depending on whether or not the car can handle it without having to build the motor. Thinking around 350-400 whp

[Sidewinderpb]

Originally Posted by Joe_E

What kind of power can the 328i tranny and n26 handle? Looking into doing a turbo upgrade depending on whether or not the car can handle it without having to build the motor. Thinking around 350-400 whp

Check out n54tech.com; generally better technical info on there.

[Stubok]

With stock internals you can make 330-340lbft of torque. The n26 is practically the same as the n20, just a change in cat. So you can tune to the same heights. The tranny is supposed to be the same as the 335i and they're putting down 600HP so if that's the case we're fine. I was told that our tranny can be coded to run as the M235i tranny.

As I'm sure you know HP is a function of torque and how long you can hold it, so for example 340lbft at 5500rpm will yield 356HP. Not including transmission loss, which is generally accepted to be 15% for a rear wheel drive car. So 400HP at the crank will measure out at about 340HP at the wheel.

Anyway my tuner has a customer in Brazil with an n20 putting down 380HP at the wheel. That's on flex fuel (which is like 110octane).

With a Built engine he is confident it could put down 500wHP. That's closed deck, 1/2" ARP head studs, forged Pistons & Rods, Upgraded rod bearings, hardened rod bolts, Stage 2 Turbo and a wet shot of Nitrous.

[add911_11]

Can I find out more information of this tuner? I am looking to upgrade my B48 engine internals and much professional opinion will be extremely helpful. Thank you

[Joe_E]

Originally Posted by Stubok

With stock internals you can make 330-340lbft of torque. The n26 is practically the same as the n20, just a change in cat. So you can tune to the same heights. The tranny is supposed to be the same as the 335i and they're putting down 600HP so if that's the case we're fine. I was told that our tranny can be coded to run as the M235i tranny.

As I'm sure you know HP is a function of torque and how long you can hold it, so for example 340lbft at 5500rpm will yield 356HP. Not including transmission loss, which is generally accepted to be 15% for a rear wheel drive car. So 400HP at the crank will measure out at about 340HP at the wheel.

Anyway my tuner has a customer in Brazil with an n20 putting down 380HP at the wheel. That's on flex fuel (which is like 110octane).

With a Built engine he is confident it could put down 500wHP. That's closed deck, 1/2" ARP head studs, forged Pistons & Rods, Road bearings, hardened rod bolts, Stage 2 Turbo and a wet shot of Nitrous.

So 350ish whp is asking for trouble? If you daily the car

[Stubok]

No 350Hp at the wheels is fine. Even Dinan have Stage 4 tune (which includes a Stage 1 Turbo Upgrade - that's a stock turbine with larger compressor) which gets almost 350HP.

Personally I'm staying at 330lbft and 315HP to the wheels until I get my bottom end done. Then my Stage 2 Turbo will give me 350-380. Wet shot of NO2 to take it over the top.

CP Carrillo for the Pistons and H-beam Rods, they also have an option for upgraded Carr rod bolts, which I have gone for.

VAC Motorsport for the upgraded Clevite bearings, and ARP head studs.

My tuner is Ricardo@ACFPerformance and they can unlock the n20 DME and flash the Bootmod3 patch so you can tune over OBD2.

[Joe_E]

Originally Posted by Stubok

No 350Hp at the wheels is fine. Even Dinan have Stage 4 tune (which includes a Stage 1 Turbo Upgrade - that's a stock turbine with larger compressor) which gets almost 350HP.

Personally I'm staying at 330lbft and 315HP to the wheels until I get my bottom end done. Then my Stage 2 Turbo will give me 350-380. Wet shot of NO2 to take it over the top.

CP Carrillo for the Pistons and H-beam Rods, they also have an option for upgraded Carr rod bolts, which I have gone for.

VAC Motorsport for the upgraded Clevite bearings, and ARP head studs.

My tuner is Ricardo@ACFPerformance and they can unlock the n20 DME and flash the Bootmod3 patch so you can tune over OBD2.

Can you list all the things required to build the bottom end. What would you need to get to build the motor to be able to handle 500whp? Wouldn't be running more than 375ish. And how much would this all cost + labor/install

[add911_11]

Thank you so much for your information.

[Stubok]

I just listed all the main things needed. Other than this it's going to be all the normal seals and gaskets. If your engine is pre-2015 I would suggest you do the timing chains and oils pump chains while the engine is apart.

For 500HP you'll need to close the deck. That's because the head is pretty hard to seal up with the sock setup and closing the deck gives more surface area to seal on and also prevents the cylinder walls from moving during the power stroke (which is what prematurely wears the head gasket and leads to it being blown).

That means the engine block needs to be machined, which is risky business, since the cylinders are not able to be honed (according to BMW) as the plasma arc spray coating is so thin. According to my research it's anywhere from 0.2mm to 0.4mm thin... so at best you could diamond hone 0.001" or maybe 0.002". Not much at all! When you close the deck (machine the slot and then press in the new support piece) the cylinders can go slightly out of round. If you can't correct it through honing, you will get more blow-by, so I'll be taking a chance on this. My machine shop says they can make the section with a little more tolerance to try limit the effect when it's pressed in. Then hone for the new rings and hope it's enough to get the cylinders into round or at least acceptable. If that doesn't work, we'll then you would need to machine the cylinders for sleeves, and then it's a lot more.

You're probably looking at 30-40 hours Labor to pull the engine, dismantle it, send off for machining, reassembly and install back. The guy I would really like to use (Alex at ABR Houston) is too much for me (quoted 7-15k depending on what is done), so I'm pulling everything together myself and will do some of the grunt work myself and get a local BMW tech I know to get it done.

Here is my budget. I've already got my Stage 2 Turbo, Downpipe, Exhaust, Intake, Chargepipes, FMIC, Catch can and tune sorted so those are not included.

Decking the block $500
Pistons & Rods $1750
Upgraded rod bolts $250
Upgraded rod bearings $350
Upgraded head studs $250
Gaskets $250.
Fluids $100.

So $3500 plus labor. Goal is to to keep around 5k.

If I add the NO2 wet shot it's obviously going to be more. About another $1k with the right controller.

[Joe_E]

Originally Posted by Stubok

I just listed all the main things needed. Other than this it's going to be all the normal seals and gaskets. If your engine is pre-2015 I would suggest you do the timing chains and oils pump chains while the engine is apart.

For 500HP you'll need to close the deck. That's because the head is pretty hard to seal up with the sock setup and closing the deck gives more surface area to seal on and also prevents the cylinder walls from moving during the power stroke (which is what prematurely wears the head gasket and leads to it being blown).

That means the engine block needs to be machined, which is risky business, since the cylinders are not able to be honed (according to BMW) as the plasma arc spray coating is so thin. According to my research it's anywhere from 0.2mm to 0.4mm thin... so at best you could diamond hone 0.001" or maybe 0.002". Not much at all! When you close the deck (machine the slot and then press in the new support piece) the cylinders can go slightly out of round. If you can't correct it through honing, you will get more blow-by, so I'll be taking a chance on this. My machine shop says they can make the section with a little more tolerance to try limit the effect when it's pressed in. Then hone for the new rings and hope it's enough to get the cylinders into round or at least acceptable. If that doesn't work, we'll then you would need to machine the cylinders for sleeves, and then it's a lot more.

You're probably looking at 30-40 hours Labor to pull the engine, dismantle it, send off for machining, reassembly and install back. The guy I would really like to use (Alex at ABR Houston) is too much for me (quoted 7-15k depending on what is done), so I'm pulling everything together myself and will do some of the grunt work myself and get a local BMW tech I know to get it done.

Here is my budget. I've already got my Stage 2 Turbo, Downpipe, Exhaust, Intake, Chargepipes, FMIC, Catch can and tune sorted so those are not included.

Decking the block $500
Pistons & Rods $1750
Upgraded rod bolts $250
Upgraded rod bearings $350
Upgraded head studs $250
Gaskets $250.
Fluids $100.

So $3500 plus labor. Goal is to to keep around 5k.

If I add the NO2 wet shot it's obviously going to be more. About another $1k with the right controller.

Really helpful response! I was going to look into ABR but i've seen that they charge an arm and leg. With that type of money I could just save up to just do a swap instead.

[nemobanks]

This was Very Informative.

[nemobanks]

Originally Posted by Stubok

With stock internals you can make 330-340lbft of torque. The n26 is practically the same as the n20, just a change in cat. So you can tune to the same heights. The tranny is supposed to be the same as the 335i and they're putting down 600HP so if that's the case we're fine. I was told that our tranny can be coded to run as the M235i tranny.

As I'm sure you know HP is a function of torque and how long you can hold it, so for example 340lbft at 5500rpm will yield 356HP. Not including transmission loss, which is generally accepted to be 15% for a rear wheel drive car. So 400HP at the crank will measure out at about 340HP at the wheel.

Anyway my tuner has a customer in Brazil with an n20 putting down 380HP at the wheel. That's on flex fuel (which is like 110octane).

With a Built engine he is confident it could put down 500wHP. That's closed deck, 1/2" ARP head studs, forged Pistons & Rods, Road bearings, hardened rod bolts, Stage 2 Turbo and a wet shot of Nitrous.

Whats needed to get to that HP 356?

[Stubok]

Originally Posted by nemobanks

Whats needed to get to that HP 356?

FBO+

I would say at the minimum you need a high flow Downpipe, Stage 1 Turbo and tune. You can look at Dinan's website too to see what they mean by Stage 4.

I would definitely do your FMIC and chargepipe. Without the FMIC the added mass flow and higher temps will heat soak your stock unit after 1 pull. Also at 22PSI your stock chargepipe will likely go pop.

[328iMSport]

Originally Posted by Stubok

FBO+

I would say at the minimum you need a high flow Downpipe, Stage 1 Turbo and tune. You can look at Dinan's website too to see what they mean by Stage 4.

I would definitely do your FMIC and chargepipe. Without the FMIC the added mass flow and higher temps will heat soak your stock unit after 1 pull. Also at 22PSI your stock chargepipe will likely go pop.

Interesting, are you saying that ~350 HP @ the rear wheels is possible with a fully bolt on setup (taking into account a 15% drivedrain loss)? That's pretty impressive from a 2.0L.

If aiming for more than 400 crank HP, then I'd have to agree that a rebuild would be required to install ARP bolts/studs and forged pistons and possibly rods. Flame ringing the heads is a good idea too, so it provides a better seal between the cylinders and head.

[Stubok]

Yes 328iMSport 350HP to the wheels on stock internals is possible. That's over 400BHP (crank) though, so not smart.

There is a FBO + Stage 2 turbo n20 in Brazil that put 380HP down to the wheels on flex fuel (about 110 octane). Amazed it didn't go bang.

That said I still think knock kills the n20, more so than any other BMW engine. And with the 10:1 CR, high AIT temps you get turning up the boost (especially with a heat soaked stock FMIC) on a stock turbo (which is not efficient at higher PR and mass flow, putting out more heat), the relatively low octane fuels here, and plugs that run hot, detonation is likely.

Also higher than expected temps and ring gaps that aren't matched accordingly cause cast Pistons to crack (we've seen a few of those too).

The on top of that I'm pretty sure the standard oil isn't good for higher output. I'm going to Motul from now on. the failures I've read about can be attributed somewhat to lubrication (spun bearings, stretched rod bolts - though Rod bolts stretch in the exhaust stroke not power stroke, so that's an interesting one, and seized cam shafts). So worth watching carefully.

Anyway I agree that over 400HP at the crank (~335HP at wheels) is not smart, and I'm not going there without Forged Pistons & Rods, upgraded Rod bolts and rod Bearings, head studs and closed deck.

It's kinda overkill I know, but then I can throw much much more at it.

[insanecoder]

Your ZF tranny can only handle 400Nm
as been said before you'd need to upgrade many other parts
the car hasnt been sourced with parts rated for that power..
yer car would be at greater risk of parts failure
If you want 360 hp consider moving up to 340i

[Stubok]

Originally Posted by insanecoder

Your ZF tranny can only handle 400Nm
as been said before you'd need to upgrade many other parts
the car hasnt been sourced with parts rated for that power..
yer car would be at greater risk of parts failure
If you want 360 hp consider moving up to 340i

First of all it's 450Nm, so at least get your numbers right if you're going to throw stones.

Also no one is saying we should go above that limit. If we can keep the torque at 332lbft and hold it up higher we can get above 350HP.

For example:

HP = (TORQUE x RPM)/5252

HP = (330 x 6000) / 5252 = 377HP

Finally there has been a lot of discussion about this, and from what I've read and heard from a couple BMW techs, the 335 and 328 with the sports automatic transmission actually have the same ZF gearbox, but just coded differently. So they both have the same rating. In which case given the power and torque tuned 335's are putting down we have more than enough head room.

[bradsm87]

Originally Posted by Stubok

First of all it's 450Nm, so at least get your numbers right if you're going to throw stones.

Also no one is saying we should go above that limit. If we can keep the torque at 332lbft and hold it up higher we can get above 350HP.

For example:

HP = (TORQUE x RPM)/5252

HP = (330 x 6000) / 5252 = 377HP

Finally there has been a lot of discussion about this, and from what I've read and heard from a couple BMW techs, the 335 and 328 with the sports automatic transmission actually have the same ZF gearbox, but just coded differently. So they both have the same rating. In which case given the power and torque tuned 335's are putting down we have more than enough head room.

I also really want to know this. It appears that it might only be the torque converter that's different. The 335i one looks like it has a couple more bits bolted to it on the RealOEM diagram but that might just be like an exhaust bracket or something. The torque converter also looks different on RealOEM. It wouldn't surprise me if it's just a matter of putting in the 335i torque converter and flashing the 335i or Alpina B3 transmission flash to the TCU.

[Stubok]

Originally Posted by bradsm87

I also really want to know this. It appears that it might only be the torque converter that's different. The 335i one looks like it has a couple more bits bolted to it on the RealOEM diagram but that might just be like an exhaust bracket or something. The torque converter also looks different on RealOEM. It wouldn't surprise me if it's just a matter of putting in the 335i torque converter and flashing the 335i or Alpina B3 transmission flash to the TCU.

I spoke to a German tuner last year and he said they have coded the 8AT in 228i and 328i to m235i. Apparently it behaves a lot better with the tuned output being similar to the stock m235i.

[bradsm87]

Originally Posted by Stubok

I spoke to a German tuner last year and he said they have coded the 8AT in 228i and 328i to m235i. Apparently it behaves a lot better with the tuned output being similar to the stock m235i.

Let me know if you find out any more details. Cheers.

[Aekdbrich]

Originally Posted by bradsm87

Let me know if you find out any more details. Cheers.

Check out the Coding section of the forum. All you do is VO Code the transmission output from "205" to "2TB". It takes about 5-10 minutes. Really easy to do and the car behaves beautifully, especially in Sport/Manual mode.

[bradsm87]

Originally Posted by Aekdbrich

Check out the Coding section of the forum. All you do is VO Code the transmission output from "205" to "2TB". It takes about 5-10 minutes. Really easy to do and the car behaves beautifully, especially in Sport/Manual mode.

That applies the "Sport Auto" option for faster shifts, but not the higher torque limit on the 335i TCU flash.