[whitesharkM2]

Originally Posted by AmuroRay

Do you have a log? Impressive mod list, basically a all the goodies.

Sorry, my data log is at The tuner is gone.

[whitesharkM2]

Originally Posted by mwpa71

Thanks for posting
That's a mild tune maybe 450 whp
Dial it up you have all the supporting mods

Edit... your intake maybe a restriction if stock.

I used the oem intake one and just changed the air filter to a BMC.
Do you think there is a problem? Is it the amount of air that enters the engine?

[VGSON]

Originally Posted by whitesharkM2

I'm not sure if my T-Map sensor oem can accept it. I heard that It only read 20 PSI.

stock tmap reads up to 22.5 & a new n20 sensor is less then $100 if you want to change it. but notify tuner when doing so

[AmuroRay]

Originally Posted by VGSON

stock tmap reads up to 22.5 & a new n20 sensor is less then $100 if you want to change it. but notify tuner when doing so

I think the stock one (at least in my M235i) maxes at 20psi. Are the cheap ones on Amazon any good?

You can change the selection in MHD, tuner isn't needed.

[F87source]

Originally Posted by AmuroRay

I think the stock one (at least in my M235i) maxes at 20psi. Are the cheap ones on Amazon any good?

You can change the selection in MHD, tuner isn't needed.

Don't buy the cheapo tmaps they're junk imo. Get a good quality OE sensor, doesn't have to be genuine bmw OE is fine.

[VGSON]

Ray, not to nitpick but im positive 22.5 is the max. When reading logs; the mani map stops at 22.5 while the other map keeps reading above that.

He’s gor a custom tune^..So i have to assume some scaling will need to be done for the new map, plus that dip at 5k needs to be fixed..Should stay on an upward trend.

[whitesharkM2]

Originally Posted by VGSON

Ray, not to nitpick but im positive 22.5 is the max. When reading logs; the mani map stops at 22.5 while the other map keeps reading above that.

He’s gor a custom tune^..So i have to assume some scaling will need to be done for the new map, plus that dip at 5k needs to be fixed..Should stay on an upward trend.

22-23psi, do you think it will be safe for the engine? I'm thinking of keeping the car for a long time. Because I use my car every day.

[VGSON]

Should be; if you do stay at current level..get your tuner to make a revision to clean up the dip at 5k

[AmuroRay]

Originally Posted by VGSON

Ray, not to nitpick but im positive 22.5 is the max. When reading logs; the mani map stops at 22.5 while the other map keeps reading above that.

He’s gor a custom tune^..So i have to assume some scaling will need to be done for the new map, plus that dip at 5k needs to be fixed..Should stay on an upward trend.

Hmm, all I know is I had a bunch of issues exceeding 20.9? I guess I could be wrong, but it’s what I was told and seen.

[VGSON]

Originally Posted by whitesharkM2

I used the oem intake one and just changed the air filter to a BMC.
Do you think there is a problem? Is it the amount of air that enters the engine?

Missed this. It could be, most recommend a bigger intake over 500wheel. Looking at logs would help determine though. do you use mhd/bm3?

[wheela]

Originally Posted by VGSON

Ray, not to nitpick but im positive 22.5 is the max. When reading logs; the mani map stops at 22.5 while the other map keeps reading above that.

He’s gor a custom tune^..So i have to assume some scaling will need to be done for the new map, plus that dip at 5k needs to be fixed..Should stay on an upward trend.

I think the max it can read depends on your local ambient conditions. I believe the stock tmap is a 2.5 bar tmap, so in absolute pressure that range is about 0 - 36.3 psia (psi absolute). But since that's absolute pressure, and our boost reads in gage pressure, you'd need to subtract your local ambient pressure from the tmap's max absolute value to figure out how high of boost you can actually read in gage pressure.

So if the max is actually 36.3 psia (I don't know if it is), at sea level with 14.7 psia ambient pressure, the max boost pressure it could read would be 21.6 psig. This number would increase with higher elevation. And it would also vary depending on what the actual maximum absolute pressure is that it can read (I don't know what the actual number is). At least that's my current understanding, I could be mistaken.

[donkey]

Is it worth doing anything about the crankhub with the 750?

[M2guru]

Originally Posted by donkey

Is it worth doing anything about the crankhub with the 750?

Been wondering this myself. Since I have 6MT vs. DCT it seems it gives me a bit of a benefit, but that doesn't mean I am safe. Was thinking about the CBC device especially since my car generally lives in the higher RPMs. I'd rather not chance it. N55s seem less prone to it than S55s. Hopefully we get some good responses here that can help us make a decision and be comfortable with it.

[wheela]

Originally Posted by donkey

Is it worth doing anything about the crankhub with the 750?

This gets discussed a lot over on f80post, as it seems to be a bigger issue for s55's. Unfortunately, there are a lot of differing theories and opinions, so it may be best to research and decide for your self if you think the risk is worth the upgrade, and if you think the upgrade will help reduce the risk.

Here are some related links you may find useful.

https://f80.bimmerpost.com/forums/sh....php?t=2077941

https://f80.bimmerpost.com/forums/sh....php?t=1226184

https://f80.bimmerpost.com/forums/sh....php?t=1560274

[wheela]

Personally, I believe it's less on an issue for n54 and n55 than s55 (s55's crankhub has more rotating mass to turn than n54 or n55). I also think the issue may be variability in the friction disks, which could potentially be exacerbated by higher power level.

If I were to do any crank hub mods for my car, I'd skip the CBC as I don't believe it does anything. For my car, I'll probably either stay on stock hub, or potentially upgrade to the newer BMW version with larger friction disks.

Edit: I'll also continue to use kick-down on my 6hp trans with xHP tune, and never lug my engine at low rpms.

[AmuroRay]

This is the S52 harmonics all over again. Likely the crank hub issue could be crank and block harmonics, due to them being stiffer. Could also be the higher redline (like it was in the S52B32 days)

[AmuroRay]

Originally Posted by wheela

I think the max it can read depends on your local ambient conditions. I believe the stock tmap is a 2.5 bar tmap, so in absolute pressure that range is about 0 - 36.3 psia (psi absolute). But since that's absolute pressure, and our boost reads in gage pressure, you'd need to subtract your local ambient pressure from the tmap's max absolute value to figure out how high of boost you can actually read in gage pressure.

So if the max is actually 36.3 psia (I don't know if it is), at sea level with 14.7 psia ambient pressure, the max boost pressure it could read would be 21.6 psig. This number would increase with higher elevation. And it would also vary depending on what the actual maximum absolute pressure is that it can read (I don't know what the actual number is). At least that's my current understanding, I could be mistaken.

I checked my logs - I maxed out at around 21 (20.7 vs a requested 22) which made the car act crazy.

[wheela]

Originally Posted by AmuroRay

I checked my logs - I maxed out at around 21 (20.7 vs a requested 22) which made the car act crazy.

That's a good data point. Did it look like it was clipping off at 20.7? Did you by chance have ambient pressure captured in you logs? If so, we could probably back-calculate the actual upper limit of the stock tmap

Edit: same for everybody else with boost getting clipped off, if you had ambient pressure logged it would be intersting to see if we calculate the same max tmap value by subtracting ambient from the clipped off boost value.

[mwpa71]

Originally Posted by wheela

Personally, I believe it's less on an issue for n54 and n55 than s55 (s55's crankhub has more rotating mass to turn than n54 or n55). I also think the issue may be variability in the friction disks, which could potentially be exacerbated by higher power level.

If I were to do any crank hub mods for my car, I'd skip the CBC as I don't believe it does anything. For my car, I'll probably either stay on stock hub, or potentially upgrade to the newer BMW version with larger friction disks.

Edit: I'll also continue to use kick-down on my 6hp trans with xHP tune, and never lug my engine at low rpms.

I think it's less of an known issue because not many n55s make s55 power. I have an f83 and a built n55 with p750. I put cbc on both.. very very few failures even with cbc only.

[AmuroRay]

Originally Posted by wheela

That's a good data point. Did it look like it was clipping off at 20.7? Did you by chance have ambient pressure captured in you logs? If so, we could probably back-calculate the actual upper limit of the stock tmap

Edit: same for everybody else with boost getting clipped off, if you had ambient pressure logged it would be intersting to see if we calculate the same max tmap value by subtracting ambient from the clipped off boost value.

Here you go:

[F87source]

Originally Posted by AmuroRay

I know the MST V2 is the biggest, but otherwise they are all basically the same.

Not anymore, bms has the largest ID turbo inlet. I talked to Payam@BMS and asked for some sizes and he gave me this image:


Credit: Payam@BMS


So judging by the measurements posted on here about the other inlets, BMS is the largest.

[wheela]

Originally Posted by AmuroRay

Here you go:

21.7 psi boost + 14.75psi ambient = 36.45 max absolute pressure (2.513 bar). That's a pretty high ambient, do you know your elevation? Oh, I see Florida, guessing very low elevation.

Does anybody else on stock tmap have any logs with clipped boost and ambient pressure logged?