[yupetc]

Folks, I've searched up quite a lot about the N52 exhaust camshaft installed onto the N55 motor. Though there's a guy posting some very potent gains after installing the N52 camshaft alone and having it tuned by BPC, I did go through the whole read when they discussed about it in technical details at SP00LSTR33T forum. It does seem to be inconclusive that the N52 exhaust camshaft's small extra duration and lift will wring out too much gain; and I know how N55 head port just isn't that great; but I still tend to believe the N52 camshaft "may" still be able to contribute to a slight more exhaust air dispel, no matter how small.

My question at hand is, if MILVs on the intake side are installed along with the N52 exhaust camshaft installation, has anyone tried this and what sort of feel or actual dyno gains have been seen on just these two mods alone? with a correct tune adjusted for valvetronic on MILVs and extra timing factored in on the exhaust cam, of course.

[LA1Z24]

I was under the impression the N52 camshaft was fake. It was never installed in that car.

[AmuroRay]

I have MILVS installed on the intake side - currently testing:

https://f87.bimmerpost.com/forums/sh....php?t=1724885

[yupetc]

Originally Posted by LA1Z24

I was under the impression the N52 camshaft was fake. It was never installed in that car.

By degree duration and slight extra lift (we're talking very minimal add) on the N62 exhaust camshaft, it may not do anything at all, but even on MILVs, we're adding about 1mm lift on the intake side if the valvetronic values are being applied in a tune, so for both mods standalone without any tune, probably nothing will happen. But I'm wondering if MILVs and the N52 camshaft both being applied onto the N55 motor may contribute to that miniscule gain. And if so I'd like to know if someone has the setup to chime in.

I already have the MILVs on my N55 motor, running MHD stage 2 tune, but I don't suppose the MILVs are contributing to any power gain because honestly speaking, I didn't feel the difference before and after the install.

My current situation is that my current N55 exhaust camshaft VANOs gear sprocket is having issues and since I'll be undo'ing the timing assembly again, I'm gauging to see if I should just put on a N52 exhaust cam while I"m at it. The job is actually very easy for me to do and if I've already gotten to tinkering with the VANOs gear, the only extra work I'll be doing is to remove the spark plug chutes and the Valvetronic motor, then I can access the exhaust camshaft, all of this is easy for me.

Based on my reading so far, MILVs and N52 exhaust camshaft does not do anything to the car without a tune (and I've seen the in-depth argument that N62 cams with a tune doesn't do shit). But on the same note, installing them also does not cause any issues nor damage effects. I might as well since I'll be breaking the chain loose again. I'm on a built motor and I just want to max out my turbo on pump gas and all other possible supporting mods. A B58TU HPFP will also be installed no later than end of year then I may do it like AmuroRay and look for BPC or Pure for help with tunes.

Anyway, my timing chain is coming loose with or without changing out the cams within next 2-3 weeks, and I do have a N52 exhaust camshaft in my garage, it's just sitting there collecting dust for a year now. Hence the posted thread.

And no I don't have a baseline dyno since I don't really have the time to go to my tune shop which is 3-hour drive away. And they may not know how to deal with the MILVs.

[thejeremyman9]

Why a b58 TU HPFP and not an aftermarket one?

[yupetc]

Originally Posted by thejeremyman9

Why a b58 TU HPFP and not an aftermarket one?

The TU pump is procured at $280. After market pumps can easily multiply it by 3-4 folds. I'm slowly walking my motor into FBO, so budgeting along a stretched timeline is my approach. And at 280 bucks, it's too good to be missed. I'm not likely to go to a full turbo swap, so at my current nearly OEM hybrid turbo setup, no real need to go for a super HPFP upgrade. I think the TU will be plenty. I don't think I'll ever run this N55 beyond 480-500whp. So a full aftermarket upgrade is an overkill in this N55 party central.

[yupetc]

Well folks, I ended up having to take my motor off the car for a full inspection because there were some rattling noise during idle, and it increases as I rev it out of idle to which the noise would go away. Car drives fine, pulls hard to redline. The rattle sounds more like a chain tensioner being loose and there's some slack in the chain for some slap. This is about 20k miles after the forged internals build which I completed back in May of 2022. So about a year later, I'm dealing with this rattle which drove me nuts.

Just got the motor out last night and mounted it onto an engine stand. As I start taking things apart, I find there are some pretty deep scoring marks on the plastic rails of oil pump chain guides. The tensioner plunger appears fine. But the oil pump chain guide needs be replaced; and henceforth, whether it'll work or not, I'll be proceeding with the N52 exhaust camshaft install to supplement my hunch that the slightly extra duration and lift will likely help the MILVs on the intake side for overall air flow improvement. I know N55 head ports are relatively weaker than the S55, but I dearly hope this little combo of MILVs and N52 exhaust cam mod will help.

Side note:
I took out my rod bearings tonight and checked its health. After 20k miles of beating on it, the bearings' sacrificial friction coating is without a scratch. This set was sold to me by Race Engineering last year and they upgraded it with Calico coating. So I just wanted to point it out so if any of you hooligans need to do rod bearings, this is a very good option to have. Part Number is CR222GPC. 20k miles of beating and it comes out unscathed.

I'll also be replacing the piston ring sets because during my last build, I've set the ring gaps according to Carrillo's guidelines, but took on larger gaps from their range thinking I'll be beating this motor quite hard. Turns out my dry compression measures between 120-130 psi throughout all cylinders and that's a bit lower than I'd like. I've also been observing loss of a quart of engine oil every 2000 miles running 5w-40 and if I use 5w-20, I'd loose the whole quart within just 1000 miles.
Since I'm taking the motor apart again, I'll be setting the piston ring gaps on the lower setting in between CP and OEM's recommended numbers. Just loads of fun learning the do's and don'ts about this motor.

[harkes]

Originally Posted by yupetc

Well folks, I ended up having to take my motor off the car for a full inspection because there were some rattling noise during idle, and it increases as I rev it out of idle to which the noise would go away. Car drives fine, pulls hard to redline. The rattle sounds more like a chain tensioner being loose and there's some slack in the chain for some slap. This is about 20k miles after the forged internals build which I completed back in May of 2022. So about a year later, I'm dealing with this rattle which drove me nuts.

Just got the motor out last night and mounted it onto an engine stand. As I start taking things apart, I find there are some pretty deep scoring marks on the plastic rails of oil pump chain guides. The tensioner plunger appears fine. But the oil pump chain guide needs be replaced; and henceforth, whether it'll work or not, I'll be proceeding with the N52 exhaust camshaft install to supplement my hunch that the slightly extra duration and lift will likely help the MILVs on the intake side for overall air flow improvement. I know N55 head ports are relatively weaker than the S55, but I dearly hope this little combo of MILVs and N52 exhaust cam mod will help.

Side note:
I took out my rod bearings tonight and checked its health. After 20k miles of beating on it, the bearings' sacrificial friction coating is without a scratch. This set was sold to me by Race Engineering last year and they upgraded it with Calico coating. So I just wanted to point it out so if any of you hooligans need to do rod bearings, this is a very good option to have. Part Number is CR222GPC. 20k miles of beating and it comes out unscathed.

I'll also be replacing the piston ring sets because during my last build, I've set the ring gaps according to Carrillo's guidelines, but took on larger gaps from their range thinking I'll be beating this motor quite hard. Turns out my dry compression measures between 120-130 psi throughout all cylinders and that's a bit lower than I'd like. I've also been observing loss of a quart of engine oil every 2000 miles running 5w-40 and if I use 5w-20, I'd loose the whole quart within just 1000 miles.
Since I'm taking the motor apart again, I'll be setting the piston ring gaps on the lower setting in between CP and OEM's recommended numbers. Just loads of fun learning the do's and don'ts about this motor.

Interesting read. Keep the posts coming

[AmuroRay]

Originally Posted by yupetc

Well folks, I ended up having to take my motor off the car for a full inspection because there were some rattling noise during idle, and it increases as I rev it out of idle to which the noise would go away. Car drives fine, pulls hard to redline. The rattle sounds more like a chain tensioner being loose and there's some slack in the chain for some slap. This is about 20k miles after the forged internals build which I completed back in May of 2022. So about a year later, I'm dealing with this rattle which drove me nuts.

Just got the motor out last night and mounted it onto an engine stand. As I start taking things apart, I find there are some pretty deep scoring marks on the plastic rails of oil pump chain guides. The tensioner plunger appears fine. But the oil pump chain guide needs be replaced; and henceforth, whether it'll work or not, I'll be proceeding with the N52 exhaust camshaft install to supplement my hunch that the slightly extra duration and lift will likely help the MILVs on the intake side for overall air flow improvement. I know N55 head ports are relatively weaker than the S55, but I dearly hope this little combo of MILVs and N52 exhaust cam mod will help.

Side note:
I took out my rod bearings tonight and checked its health. After 20k miles of beating on it, the bearings' sacrificial friction coating is without a scratch. This set was sold to me by Race Engineering last year and they upgraded it with Calico coating. So I just wanted to point it out so if any of you hooligans need to do rod bearings, this is a very good option to have. Part Number is CR222GPC. 20k miles of beating and it comes out unscathed.

I'll also be replacing the piston ring sets because during my last build, I've set the ring gaps according to Carrillo's guidelines, but took on larger gaps from their range thinking I'll be beating this motor quite hard. Turns out my dry compression measures between 120-130 psi throughout all cylinders and that's a bit lower than I'd like. I've also been observing loss of a quart of engine oil every 2000 miles running 5w-40 and if I use 5w-20, I'd loose the whole quart within just 1000 miles.
Since I'm taking the motor apart again, I'll be setting the piston ring gaps on the lower setting in between CP and OEM's recommended numbers. Just loads of fun learning the do's and don'ts about this motor.

S55 and N55 have the same head.

[yupetc]

Originally Posted by AmuroRay

S55 and N55 have the same head.

Can you confirm this statement? Just really curious now. Because I've always known the two heads to be different. If they are the same, I'd like to look more into it and find out more. Because that would indicate a lot of parts being interchangeable between the two.

[AmuroRay]

Originally Posted by yupetc

Can you confirm this statement? Just really curious now. Because I've always known the two heads to be different. If they are the same, I'd like to look more into it and find out more. Because that would indicate a lot of parts being interchangeable between the two.

I believe the only difference is related to coolant passages - headflow (and cams/Valvetronic and VVT system) are the same.

http://s3.bimmerfile.com.s3.amazonaw...S55-Engine.pdf