E90Post
 


Studio RSR
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N55 Turbo Engine Tuning and Exhaust Modifications - 335i Tuning > How about this HP combo



Reply
 
Thread Tools Search this Thread
      12-14-2016, 01:34 PM   #23
JETmn
Lieutenant Colonel
United_States
245
Rep
1,595
Posts

Drives: 2011 335i xDrive Msport
Join Date: Apr 2013
Location: Orlando

iTrader: (0)

Garage List
2011 335Xi  [0.00]
Quote:
Originally Posted by Rob_BMW_PNW View Post
I havent seen enough evidence that it does this with stock turbo, could be wrong

Not all psi is equal when you upgrade to the PS2 or even PS1
The psi (pressure) is the same, but the temperature is lower on the bigger turbo so their is more oxygen in the same volume. That is where you get the extra power at the same psi for the ps2 vs stock or ps1.
__________________
2011 335Xi 6AT - VRSF catless DP - VRSF 7" FMIC with turbo inlet pipe - VRSF chargepipe - Pure Stage 1 turbo - JB4 - E30 - xHP Stage 3 - Strongflex tension bushings - Whiteline RSFB - UUC rear swaybar
Appreciate 0
      12-14-2016, 02:02 PM   #24
Rob_BMW_PNW
Captain
126
Rep
609
Posts

Drives: 135i 2011
Join Date: Jan 2016
Location: PNW

iTrader: (3)

Quote:
Originally Posted by JETmn View Post
The psi (pressure) is the same, but the temperature is lower on the bigger turbo so their is more oxygen in the same volume. That is where you get the extra power at the same psi for the ps2 vs stock or ps1.
Not all PSI is created equal...

The wheel and inlets/outlets are larger, how is it 'the same'?

How is temperature lower on a bigger turbo?
__________________
2011 135i N55 Pure Stage 2 Turbo, Stage 2 LPFP, N54tuning.com Catless DP, Cobb Drop in, AEM Meth Kit, MHD, BMS OCC, Tuned by WedgePerformance
PI, LSD, and Dif lockdown coming soon
Appreciate 0
      12-14-2016, 03:18 PM   #25
Cory S
Major
Cory S's Avatar
United_States
305
Rep
1,163
Posts

Drives: 2011 335i-X
Join Date: Oct 2015
Location: N.H.

iTrader: (0)

Quote:
Originally Posted by JETmn View Post
The psi (pressure) is the same, but the temperature is lower on the bigger turbo so their is more oxygen in the same volume. That is where you get the extra power at the same psi for the ps2 vs stock or ps1.
Actually, when people say you are getting more power from the same PSI, it's because they seem to forget that the same PSI peak is being up in the higher RPM range, where the engine consumes more air and is more efficient also. Yes, the charge will be a little cooler, but that's what the intercoolers are for also.

So a stock N54/55 at 17psi at 4600rpm may be very close in output, but the larger compressor keeps holding pressure higher in the RPM range after that. That's where the output peak is increased.
Appreciate 0
      12-14-2016, 03:22 PM   #26
Jeff@TopGearSolutions
Jeff@TopGearSolutions's Avatar
United_States
3441
Rep
79,212
Posts

Drives: C6 Z06, 09 335i, 10 335xi
Join Date: Dec 2008
Location: www.TopGearSolutions.com

iTrader: (37)

Quote:
Originally Posted by Rob_BMW_PNW View Post
Pointless to get the GFB if you are on a stock turbo, such a pain to put it in since you have to remove your water pump and tstat.
I kindly disagree, we have had many customers on stock turbos purchase it and found out their stock DV was leaking. It increased their boost response, lowered WGDC, ETC

Obviously on a brand new car it might no do much but as that stock DV becomes weak, it definitely helps restore power. I can say that with a straight face all day.
Appreciate 2
      12-15-2016, 07:50 AM   #27
JETmn
Lieutenant Colonel
United_States
245
Rep
1,595
Posts

Drives: 2011 335i xDrive Msport
Join Date: Apr 2013
Location: Orlando

iTrader: (0)

Garage List
2011 335Xi  [0.00]
Quote:
Originally Posted by Cory S View Post
Actually, when people say you are getting more power from the same PSI, it's because they seem to forget that the same PSI peak is being up in the higher RPM range, where the engine consumes more air and is more efficient also. Yes, the charge will be a little cooler, but that's what the intercoolers are for also.

So a stock N54/55 at 17psi at 4600rpm may be very close in output, but the larger compressor keeps holding pressure higher in the RPM range after that. That's where the output peak is increased.
No, that isn't the only reason it can happen. If you ran same boost curve on both turbos, the ps2 would still make more power. It can happen because of being able to hold boost higher, but if you take a smaller turbo that is getting to the edge of its efficiency rating (like the N55 stocker or ps1) and compare it to the PS2, you will get a much lower outlet temp. Yes the intercooler lowers the temp, but it isn't near 100% efficient and you will end up with lower AIT with the larger turbo. This is also a huge benefit of meth/water/nitrous injection.

Quote:
Originally Posted by Rob_BMW_PNW View Post
Not all PSI is created equal...

The wheel and inlets/outlets are larger, how is it 'the same'?

How is temperature lower on a bigger turbo?
That is not correct at all, pressure is pressure. It is just a reading, so yes all PSI are equal. Now, that is not all of the equation that we are interested in. The equation is PV=nRT. R is a constant and N is the amount of the substance, so we can take them out for comparison purposes, so PV=T. What we have left is pressure * volume = temp. We know the volume inside the turbo tract is constant, so we can take out volume too. That means if we lower the temp, the pressure will also lower. So the same amount of oxygen is available for combustion at a lower pressure if we lower the temperature. A 20*F drop in IAT's will be an increase of 4% in power at the same boost level.
__________________
2011 335Xi 6AT - VRSF catless DP - VRSF 7" FMIC with turbo inlet pipe - VRSF chargepipe - Pure Stage 1 turbo - JB4 - E30 - xHP Stage 3 - Strongflex tension bushings - Whiteline RSFB - UUC rear swaybar
Appreciate 0
      12-15-2016, 08:00 AM   #28
DOCTOR.Y
Eric_Y
Australia
101
Rep
455
Posts

Drives: 2016 340i, 2010 E92 M3
Join Date: Sep 2015
Location: Sydney

iTrader: (0)

Garage List
2016 bmw m3 f80  [0.00]
2010 M3 E92  [0.00]
Quote:
Originally Posted by Jeff@TopGearSolutions View Post
Quote:
Originally Posted by Rob_BMW_PNW View Post
Pointless to get the GFB if you are on a stock turbo, such a pain to put it in since you have to remove your water pump and tstat.
I kindly disagree, we have had many customers on stock turbos purchase it and found out their stock DV was leaking. It increased their boost response, lowered WGDC, ETC

Obviously on a brand new car it might no do much but as that stock DV becomes weak, it definitely helps restore power. I can say that with a straight face all day.
How do we know if DV is leaking? Anyway to diagnose it?
Appreciate 0
      12-15-2016, 12:06 PM   #29
Rob_BMW_PNW
Captain
126
Rep
609
Posts

Drives: 135i 2011
Join Date: Jan 2016
Location: PNW

iTrader: (3)

Quote:
Originally Posted by JETmn View Post
No, that isn't the only reason it can happen. If you ran same boost curve on both turbos, the ps2 would still make more power. It can happen because of being able to hold boost higher, but if you take a smaller turbo that is getting to the edge of its efficiency rating (like the N55 stocker or ps1) and compare it to the PS2, you will get a much lower outlet temp. Yes the intercooler lowers the temp, but it isn't near 100% efficient and you will end up with lower AIT with the larger turbo. This is also a huge benefit of meth/water/nitrous injection.



That is not correct at all, pressure is pressure. It is just a reading, so yes all PSI are equal. Now, that is not all of the equation that we are interested in. The equation is PV=nRT. R is a constant and N is the amount of the substance, so we can take them out for comparison purposes, so PV=T. What we have left is pressure * volume = temp. We know the volume inside the turbo tract is constant, so we can take out volume too. That means if we lower the temp, the pressure will also lower. So the same amount of oxygen is available for combustion at a lower pressure if we lower the temperature. A 20*F drop in IAT's will be an increase of 4% in power at the same boost level.
I was referring to psi in making power
19 psi in a stock turbo, is not the same as 19 psi in a PS2 car
__________________
2011 135i N55 Pure Stage 2 Turbo, Stage 2 LPFP, N54tuning.com Catless DP, Cobb Drop in, AEM Meth Kit, MHD, BMS OCC, Tuned by WedgePerformance
PI, LSD, and Dif lockdown coming soon
Appreciate 0
      12-15-2016, 02:08 PM   #30
Jeff@TopGearSolutions
Jeff@TopGearSolutions's Avatar
United_States
3441
Rep
79,212
Posts

Drives: C6 Z06, 09 335i, 10 335xi
Join Date: Dec 2008
Location: www.TopGearSolutions.com

iTrader: (37)

Quote:
Originally Posted by Eric_Y View Post
How do we know if DV is leaking? Anyway to diagnose it?
By the time you get to it and get it out (2-3 hrs) you mine as well spend the $130~ just to replace it. It's such an inexpensive upgrade worth every penny once installed.

To answer your question, IDK how to test it but I imagine a pressure test of some sort would be the answer.
Appreciate 0
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 03:56 AM.




e90post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST