[shiv@vishnu]

Originally Posted by TTurboBullett

those #'s are only part of the equation you need to know vehicle displacement - volumetric efficiency and redline to know exactly where the turbos are beeing run at any point in the compressor map

+1. Not to mention the effects of the turbine housing/wheel. It can only make things worse.

Shiv

[TTurboBullett]

Originally Posted by shiv@vishnu

+1. Not to mention the effects of the turbine housing/wheel. It can only make things worse.

Shiv

the best things these turbine sides have going for them is the BIG wastegates, which is a blessing in regards to pushing high power levels if you can run a turbo you dont have to push to hell, and a curse in regards to keeping them shut at high turbine backpressures. can u say CATCH 22?

[Bubbles]

Originally Posted by JesusFrEAk

TTurboBullett so are you saying people can run the stock turbos at 18psi producing 480rwp and be save for what 1 yr, 2 yrs ??? how long???

He won't know, he just stated it's out of spec range at that psi. It could be all or nothing.

[TTurboBullett]

Originally Posted by Bubbles

He won't know, he just stated it's out of spec range at that psi. It could be all or nothing.

exactly I know guys with Evos and SRT-4s that run waaaay out of the compressor map for 50-60k miles and some peoples turbos blow up after a few WOT runs. when youre dealing with a piece of metal spinning 100,000+ revolutions a minute and putting a load on each end of the shaft you are literally playing russian roulette

[JesusFrEAk]

I see. I was just trying to determine based on the data and TTurboBullett's translation, if these turbo's can reliably push that much power for a few years. As I am thinking of getting all the bolt-ons and it would be nice to know they will last a while vs. winging it and hoping they don't go at any given time.

[TTurboBullett]

Originally Posted by JesusFrEAk

I see. I was just trying to determine based on the data and TTurboBullett's translation, if these turbo's can reliably push that much power for a few years. As I am thinking of getting all the bolt-ons and it would be nice to know they will last a while vs. winging it and hoping they don't go at any given time.

the closer to the center and bottom of the compressor map you stay, theoretically the longer the turbos will last.

[JesusFrEAk]

so theoretically these turbos with all bolt ons should last a long time if power stays around 380whp??

Edit: sorry edited the 480hp number to 380hp

[scottp999]

Originally Posted by JesusFrEAk

so theoretically these turbos with all bolt ons should last a long time if power stays around 480whp??

I would guess (my technical contribution) more like 380whp

[smdandb2]

Originally Posted by TTurboBullett

exactly I know guys with Evos and SRT-4s that run waaaay out of the compressor map for 50-60k miles and some peoples turbos blow up after a few WOT runs. when youre dealing with a piece of metal spinning 100,000+ revolutions a minute and putting a load on each end of the shaft you are literally playing russian roulette

Yeah, and if you blow up a turbo on a Neon or an Evo you're out a few hours of labor and a couple hundred getting it replaced. Maybe $1500 if you order one from the stealer.

I don't see that being the case right now in the BMW world.

The roundel just about guarantees a price premium over other makes and models.

[DMETune]

Originally Posted by TTurboBullett

according to the posted data the OP said that the turbos were good for 42.25lb airflow 1 lb airflow is good for approx 10hp SO 42.25x10= 422.5hp

peak boost is shown in the middle of the map as 2.7bar (2.7 x 14.6psi = 39 - 14.6(atmospheric pressure) = 24.8 MAX PSI)

max boost at max flow/choke point is 2.2 bar (2.2 x 14.6 = 32 psi -14.6(atmospheric pressure) = 17.52 PSI BOOST at choke point)

once someone translates the map to either CFM or Lb/min and puts some efficiency % to the islands I can get as TECH as you want

Anything missing?

Two things:
- Firstly, I was the OP.

- We may be saying the same things here, but the key correction that's missing is efficiency. It may create 24.8psi of pressure, it's important to consider how much of that pressure is heat and how much is actual density gain. Also, we cannot dismiss the pressure drop across the intercooler.

In short, this information is not suggesting that these turbos should be running at 24psi peak and 17 by redline. Peak efficiency is well below these figures.

[TTurboBullett]

Originally Posted by DMETune

Two things:
- Firstly, I was the OP.

- We may be saying the same things here, but the key correction that's missing is efficiency. It may create 24.8psi of pressure, it's important to consider how much of that pressure is heat and how much is actual density gain. Also, we cannot dismiss the pressure drop across the intercooler.

In short, this information is not suggesting that these turbos should be running at 24psi peak and 17 by redline. Peak efficiency is well below these figures.

I think we are definitely stating the SAME things here. I stated we need efficiency information and to use the engines displacement, rpm and volumetric efficiency to plot where end users are pushing these turbos. If someone can get the efficiency percentages I can do all of the other calcs. Lastly all the data I posted was compressor outlet pressures NOT intake manifold pressure.

[Prince ///M]

Originally Posted by TTurboBullett

I think we are definitely stating the SAME things here. I stated we need efficiency information and to use the engines displacement, rpm and volumetric efficiency to plot where end users are pushing these turbos. If someone can get the efficiency percentages I can do all of the other calcs. Lastly all the data I posted was compressor outlet pressures NOT intake manifold pressure.

I think that you will never have VE of the engine... but adiabatic efficiency of the compressor is already in the table of the first post.

[A418t81]

VE plays into the the PR required for the amount of flow. That takes into account all the turbine wheel restrictions, etc. I'd say that it's been proven that ~17 psi is around 420 whp with the right octane. Falls right into line, right in the region of maximum flow for given PR.

Also, the rpm this compressor needs to make a nice amount of boost is lower than I expected for it's size. These things can be pushed way beyond the 310-320 whp that the flash tuners keep harping on as the max of the hardware. I'd say that is absolutely not the case with the data presented.

[smdandb2]

Here is the map cleaned up a bit. I was able to interpolate the data to get the efficiency islands made with a good amount of certaintly.

I know you need to know the VE of the N54 amongst other things to get really correct calculations, but if you just work on a VE of 90% you can see some of the PRs obtained with the tunes that the turbo is going WAY outside the map. Shaft speeds must go thru the roof when trying to hit higher boost levels in the upper RPMs. No wonder power tapers of so much on the dynos you see.

[DMETune]

Originally Posted by smdandb2

Here is the map cleaned up a bit. I was able to interpolate the data to get the efficiency islands made with a good amount of certaintly.

I know you need to know the VE of the N54 amongst other things to get really correct calculations, but if you just work on a VE of 90% you can see some of the PRs obtained with the tunes that the turbo is going WAY outside the map. Shaft speeds must go thru the roof when trying to hit higher boost levels in the upper RPMs. No wonder power tapers of so much on the dynos you see.

Well done! I'll put this up in the OP.

[pronacyk]

Great! It'd be neat to see some comparisons of stock vs tuned operating lines overlayed on this compressor map.

[1clean335i]

Originally Posted by scalbert

Good to finally see.

thanks for posting this info

[Bubbles]

Originally Posted by smdandb2

Here is the map cleaned up a bit. I was able to interpolate the data to get the efficiency islands made with a good amount of certaintly.

I know you need to know the VE of the N54 amongst other things to get really correct calculations, but if you just work on a VE of 90% you can see some of the PRs obtained with the tunes that the turbo is going WAY outside the map. Shaft speeds must go thru the roof when trying to hit higher boost levels in the upper RPMs. No wonder power tapers of so much on the dynos you see.

Shouldn't you be working on more important stuff?

[Prince ///M]

Someone on another forum posted the superposition of opertating lines depending on rpm with the compressor map.

In red there is also the curve relative to Procede boost (as logged from stage 0 non DD)... and it seems to be a lot outside range at high rpm.

Could someone confirm this kind of behaviour?

[Ilma]

I know from your posts that you are not particularly fond of the Procede, but in all fairness, other tunes are running similar boost profiles and psi......so these conclusions wouldn't apply to just the Procede I would think.

[Prince ///M]

Originally Posted by Ilma

I know from your posts that you are not particularly fond of the Procede, but in all fairness, other tunes are running similar boost profiles and psi......so these conclusions wouldn't apply to just the Procede I would think.

I'm not against Procede (I use it and I'm very satisfied, more than with JB3)... I'm trying to understand how our cars work and how to improve performances and reliability.

I'm also unsure about the graph I posted... so I hope that someone with better knowledge can replicate the same analysis.

[Ilma]

Originally Posted by Prince ///M

I'm not against Procede (I use it and I'm very satisfied, more than with JB3)... I'm trying to understand how our cars work and how to improve performances and reliability.

I'm also unsure about the graph I posted... so I hope that someone with better knowledge can replicate the same analysis.

Ok....sorry for the comment.

I do agree with your premise.