[CaptainInsano]

Originally Posted by Beemw335

These turbos can handle way over 11psi lol.
Show me a graph or proof where it shows that 11 pdi is the effincency range!
And dont show me the sticky becausr nobody is able to graph a boost vs rpm curve of it efficency...I say these turbos are efficent up until 15-16 psi.

I just went to look at the compressor map in the sticky. Looks like you can still achieve 74% efficiency at ~17psi, but 75% only until 1.9 bar(12psi)? Unless I am reading this totally wrong.

Does this MHI data not apply to our turbos for some reason? Aren't you just supposed to look at the center of the efficiency islands and calculate the boost delta from atmospheric?

Not trying to be a douche, just trying to learn.

[rader1]

Originally Posted by CaptainInsano

I just went to look at the compressor map in the sticky. Looks like you can still achieve 74% efficiency at ~17psi, but 75% only until 1.9 bar(12psi)? Unless I am reading this totally wrong.

Does this MHI data not apply to our turbos for some reason? Aren't you just supposed to look at the center of the efficiency islands and calculate the boost delta from atmospheric?

Not trying to be a douche, just trying to learn.

+1
Would someone please point to a DIY or good source on how to read turbo effeciency chart

[dzenno]

Originally Posted by rader1

+1
Would someone please point to a DIY or good source on how to read turbo effeciency chart

+10

I've always found those charts amusing

[Beemw335]

I dont know how to read the graph either, but Im just saying that in my opinion if you stay below 15-16 pdi you will never have a problem.
Wwn if you occasionaly crank it up a bit more on race gas it isnt tol bad, but boost needs to drop down a lot past 6000rpm to avoid overspool.

[Bakeme521]

Originally Posted by GeorgiaTech335coupe

Whoever told you that knows absolutely nothing about this car...

this

[Brey335i]

With the proper failsafes and some intellect, this motor is almost indestructible.

You just have to make sure your AFR is in the right range

[Beemw335]

The motor is indestructable? Yes
But how about the turbos? Far from it

At my dealer, I know of 3 people who have blown turbos due to tunes and 1 other guy who melted the internals of his cats

These cars are very strong, but never run too mich boost without the right gas and supporting mods

[bulldog_yyc]

yes! see this thread:
http://www.e90post.com/forums/showthread.php?t=556860

[Jeff@TopGearSolutions]

Originally Posted by Beemw335

The motor is indestructable? Yes
But how about the turbos? Far from it

At my dealer, I know of 3 people who have blown turbos due to tunes and 1 other guy who melted the internals of his cats

These cars are very strong, but never run too mich boost without the right gas and supporting mods

I know a half a dozen middle aged gents that have blown turbos on stock vehicles its usually the luck of the draw.

[RambleJ]

Originally Posted by Jeff@topgearsolutions

I know a half a dozen middle aged gents that have blown turbos on stock vehicles its usually the luck of the draw.

I was going to say the same thing.

[Jeff@TopGearSolutions]

Originally Posted by RambleJ

I was going to say the same thing.

Atleast we can agree on something

[3-Serious]

So from what I got from this thread is its safe to mod these cars as long as you take the following precautions... basically this is just like every other car I've modded. lol For some reason people made it seem like as soon as you touched it the car was done for. I guess i didn't do as much research as I thought I did.

[JB335]

I think, less than 1% of tuned 335's suffer severe engine damage, is an accurate statistic.

[Dr_Dirt]

Originally Posted by CaptainInsano

I just went to look at the compressor map in the sticky. Looks like you can still achieve 74% efficiency at ~17psi, but 75% only until 1.9 bar(12psi)? Unless I am reading this totally wrong.

Does this MHI data not apply to our turbos for some reason? Aren't you just supposed to look at the center of the efficiency islands and calculate the boost delta from atmospheric?

Not trying to be a douche, just trying to learn.

for reference 1 bar = 14.7 psi

[creaminz]

PROceed tune'd for 53000 miles. I just hit 454 rwhp, 466 rwtq with newest PROceed map & PWM meth kit with Full bolt on mods. Car is running better than ever. No tune on N54 is like eating burger without fries & coke.

[RR80]

I run procede all the time with 0 problem (only some bugs from the map). If you're not set it to some crazy boost level with stock turbo you will be ok!

[Joshboody]

Originally Posted by CaptainInsano

I just went to look at the compressor map in the sticky. Looks like you can still achieve 74% efficiency at ~17psi, but 75% only until 1.9 bar(12psi)? Unless I am reading this totally wrong.

Does this MHI data not apply to our turbos for some reason? Aren't you just supposed to look at the center of the efficiency islands and calculate the boost delta from atmospheric?

Not trying to be a douche, just trying to learn.

Actually I learned something new on this subject. I always thought compressor efficiency was the relationship of heat versus volume of air... which it is, BUT in actuality it's: actual heat versus theoretical heat determined by the laws of thermodynamics. Same thing, but makes more sense.

Pressure y and flow x. pressure is ratio of absolute to baro / flow can be volume or mass flow (includes air density or not). Efficiency and compressor rpm are referenced. The very left side is surge line... too much pressure versus flow (stalled compressor) or right side choke point... not enough compressor air volume to meet pressure ratio (100% WGDC).

For "safe boost" it depends on the volume of air required and this increases with rpm of course. So you would basically plot a straight line at your target boost pressure. Efficiency will be greatest in the mid-range and then start declining as your flow increases due to rpm. Flow is NOT linear with rpm though as VE (torque) drops with rpm.

We need more threads like this on e90post. No one answered my VANOS questions

[tibra1]

Originally Posted by Beemw335

The motor is indestructable? Yes
But how about the turbos? Far from it

At my dealer, I know of 3 people who have blown turbos due to tunes and 1 other guy who melted the internals of his cats

These cars are very strong, but never run too mich boost without the right gas and supporting mods

Turbos and seals will definitly be a casuality of running boosted for sustained periods..there just no getting around it

[Litos]

lol @ stock turbos being efficient up to 11psi

HAHAHA !!!!!!

[CaptainInsano]

Originally Posted by Litos

lol @ stock turbos being efficient up to 11psi

HAHAHA !!!!!!

If you know something please chime in. All the information I have is from the MHI data.

Take the most efficient island, find the max total pressure, subtract 1 bar(14.7 psi, thanks Dr Dirt). That should give the maximum boost for the most efficient island under ideal flow rates. Am I doing this wrong?

Where do these turbos start to become inefficient? Why?

We need a graph which shows efficiency vs RPM, since we don't know what our flow rates are at different RPMs, or what boost levels are most efficient at the flow rates we produce.(thanks Joshboody).

11-12 psi seems reasonable to me considering stock boost and MHI data. People are running much more boost than this (myself included), but that doesn't mean we aren't out of the efficiency range on these tiny little turbos.

As I said before, not trying to be a douche just trying to learn.

Thanks.

[Joshboody]

You can calculate general air volume / mass for x horsepower
- use the dyno thread for horsepower reference (at the crank).
- VE will follow the torque curve
- VE will increase with boost
- Mass air flow is directly proportional to hp
- And we know the boost people are running for certain hp levels.

Should provide a fairly accurate plot. I’ve seen this plotted by Cobb, but they assumed a steady VE using MAF (not actual, calculated) logged by the DME. I would start with VE of 110% at peak torque for FBO… but I really don’t know.

Much of this info should be in the turbo sticky, but haven’t looked through it all.