A NEW TURBO TUNING QUESTION?

[turbo535i]

car: 87 535i

OK next question!

ive been looking in tuning more and more since i finally have a new job and ive been making money lol well heres the question...

what are my options and whats the easiest for actual upgrade... i have no interest in running an FMU i want a true tune!

i've heard of the Super ETA harness swap and a couple other things i would prefer a plug and play unit if possible and i will be swapping in the 60-2 crank sensor and balancer and the TPS

what else would i need to complete this...what are my options?

[George]

1. i keep getting told to get the 60-2 crank sensor from another bmw...can anyone tell me specifically what car to get this off of.

88/89 635csi
all e34 535i
all e32 735i

2. im looking to get bigger injectors to support boost and what not looking at running 15psi maybe a little more can anyone tell me what the best ones are to run on the car and if there are any cars i could possibly get these injectors from.

You can't reasonably pick injectors based off of boost pressure. A 50mm turbo will require different (read: larger) injectors than a 67mm turbo at the same pressure. Make a plan for what type of power you want to make and proceed from there. A 42# injector will be good for over 400hp.

3. im also trying to figure out what MS unit to go with ive been told that there isnt a PNP unit for our cars...and that it has to be wired into the wiring harness for our cars...is there a way to get around this is there another harness that im able to use from a different bmw to be able to use a PNP unit or am i SOL and have to do a full wire in ?

Nothing is truly PNP, but Peter Florance can get you pretty close. I wouldn't use anyone else.

[turbo535i]

1. i keep getting told to get the 60-2 crank sensor from another bmw...can anyone tell me specifically what car to get this off of.

88/89 635csi
all e34 535i
all e32 735i

2. im looking to get bigger injectors to support boost and what not looking at running 15psi maybe a little more can anyone tell me what the best ones are to run on the car and if there are any cars i could possibly get these injectors from.

You can't reasonably pick injectors based off of boost pressure. A 50mm turbo will require different (read: larger) injectors than a 67mm turbo at the same pressure. Make a plan for what type of power you want to make and proceed from there. A 42# injector will be good for over 400hp.

3. im also trying to figure out what MS unit to go with ive been told that there isnt a PNP unit for our cars...and that it has to be wired into the wiring harness for our cars...is there a way to get around this is there another harness that im able to use from a different bmw to be able to use a PNP unit or am i SOL and have to do a full wire in ?

Nothing is truly PNP, but Peter Florance can get you pretty close. I wouldn't use anyone else.

thank you helped a lot id like to make between 350 and 400 hp

[turbo535i]

btw who is peter floreance or what is he? im trying to figure this out i am trying to read and learn as much as possible

[George]

http://www.pftuning.com/

[turbo535i]

thank you for putting me in contact with him!

[turbo535i]

i was also told to upgrade my TPS? what sensor do i upgrade to? what car is it available from?

[George]

i was also told to upgrade my TPS? what sensor do i upgrade to? what car is it available from?

The variable TPS from the b35 auto or the M50 TPS (with adapter) can be used.

[turbo535i]

i was also told to upgrade my TPS? what sensor do i upgrade to? what car is it available from?

The variable TPS from the b35 auto or the M50 TPS (with adapter) can be used.

thanks what car did the b35 come in lol i know im a newb im horrible with bmw's and their combinations!

[turbo535i]

nvm i found it i need to search instead of just asking questions sorry about the trouble guys

[altus22]

2. im looking to get bigger injectors to support boost and what not looking at running 15psi maybe a little more can anyone tell me what the best ones are to run on the car and if there are any cars i could possibly get these injectors from.

You can't reasonably pick injectors based off of boost pressure. A 50mm turbo will require different (read: larger) injectors than a 67mm turbo at the same pressure. Make a plan for what type of power you want to make and proceed from there. A 42# injector will be good for over 400hp.

Besides IAT, why would the injector size need to change between turbos? As long as both can flow what the M30 needs them to at x psi, you will have the same amount of air and need the same amount of fuel.

[George]

As long as both can flow what the M30 needs them to at x psi, you will have the same amount of air

No you won't. I'm too tired to spell it all out but a 50mm turbo and a 70mm turbo will make very different power on an M30 at the same boost level. Please do some more reading.

[Brad D.]

As long as both can flow what the M30 needs them to at x psi, you will have the same amount of air

No you won't. I'm too tired to spell it all out but a 50mm turbo and a 70mm turbo will make very different power on an M30 at the same boost level. Please do some more reading.

This is correct. Given two different turbos, each with very different flow capabilities, they will NOT flow the same air mass at the same boost pressure. Like George, I'm at work and don't have time to spell it out, but don't want anyone to get the wrong idea.

[turbo535i]

i understand this but at the same time the same amount of air flow would require the same injector size so either a 50mm or a 70mm would run fine with 450cc injectors!

[Brad D.]

Correct, a constant air mass would require the same amount of fuel. These air masses would just be supplied at different pressure ratios between the different turbos.

[George]

Just a few days ago I explained to a friend the concept behind bigger turbo less boost vs smaller turbo more boost concept. I hope this makes sense.

The actual mass of air (lets keep it at lbs/min) varies for a given turbo and engine. The two main factors are pressure and heat.

What people need to understand is that compressor efficiency varies a boat load. Compressor efficiency can be summed up as how little heat you can add to the charge air for a given amount of compression. This efficiency can go up to ~80% for modern turbos and will drop way below 50% for certain engine/turbo combinations.

Again, I will use the 50mm vs 70mm inducer comparison. At redline (at lets says 15psi) a 50mm turbo will be running at a significantly less efficient region than a 70mm turbo. The difference can be as much as 20%+. This is a wide generalization but for the sake of argument, lets assume its true for now.

We are assuming that the engine hasn't reached its detonation limit on either set-up.

Now, if we were to look at the post compressor air temperature (again, at redline) we would see that the 70mm turbo would be significantly cooler. You can see how in theory, you can reduce the boost a few psi and still end up with the same theoretical air flow (for the same ambient temps in both cases). It all comes down to efficiecy.


Now, this isn't to say that you should pick the largest turbo possible. Two reasons:

A) it might not ever spool

B) your mid range efficiency might be so terrible that you temps sky rocket.

This is why you try to pick a turbo that can hold a decent efficiency for your boost level until redline.


For anyone who has ever messed around with the turbos that come stock on factory turbo'd cars, you'll find that they are designed to spool almost instantly. If you increase your boost pressure to something significantly higher than what the car ran stock, you'll need to taper it down by redline because the turbo has reached such an inefficient zone.

[altus22]

Taking into account different temperatures and efficiencies, I totally agree with the need for more fuel with a larger (more efficient) turbo. That is why I prefaced my post with besides IAT. I'm glad we all agree. I like to size injectors without taking into account compressor inefficiencies so that I don't run out of injector, unless there will be an idle problem, of course.

I'm sorry for the thread hijack.

[Gunni]

Just a few days ago I explained to a friend the concept behind bigger turbo less boost vs smaller turbo more boost concept. I hope this makes sense.

The actual mass of air (lets keep it at lbs/min) varies for a given turbo and engine. The two main factors are pressure and heat.

What people need to understand is that compressor efficiency varies a boat load. Compressor efficiency can be summed up as how little heat you can add to the charge air for a given amount of compression. This efficiency can go up to ~80% for modern turbos and will drop way below 50% for certain engine/turbo combinations.

Again, I will use the 50mm vs 70mm inducer comparison. At redline (at lets says 15psi) a 50mm turbo will be running at a significantly less efficient region than a 70mm turbo. The difference can be as much as 20%+. This is a wide generalization but for the sake of argument, lets assume its true for now.

We are assuming that the engine hasn't reached its detonation limit on either set-up.

Now, if we were to look at the post compressor air temperature (again, at redline) we would see that the 70mm turbo would be significantly cooler. You can see how in theory, you can reduce the boost a few psi and still end up with the same theoretical air flow (for the same ambient temps in both cases). It all comes down to efficiecy.


Now, this isn't to say that you should pick the largest turbo possible. Two reasons:

A) it might not ever spool

B) your mid range efficiency might be so terrible that you temps sky rocket.

This is why you try to pick a turbo that can hold a decent efficiency for your boost level until redline.


For anyone who has ever messed around with the turbos that come stock on factory turbo'd cars, you'll find that they are designed to spool almost instantly. If you increase your boost pressure to something significantly higher than what the car ran stock, you'll need to taper it down by redline because the turbo has reached such an inefficient zone.

What is even more important is exhaust manifold backpressure caused from the size of the turbine housing and the turbine wheel. That is one of the biggest if not biggest factors when it comes to airflow mass in turbocharged engines.

[George]

What is even more important is exhaust manifold backpressure caused from the size of the turbine housing and the turbine wheel. That is one of the biggest if not biggest factors when it comes to airflow mass in turbocharged engines.

100% correct. If you log EGT on the dyno or street , you'll see the EGT decrease with each sucessively larger turbine wheel. I'm currently doing this on stock Audi turbos with upgraded compressor and turbine wheels in the stock housing(s). I've been playing with porting the internal wastegates to alter the flow.

And to add onto that, the ignition detonation limit will begin to work in your favor as you keep EGTs to a reasonable level.

[Canuck YYC]

Here's what brought it together for me, as I was struggling with the idea. I wasn't having an issue with the temperature effects, but the pressure ratio/flow statement.

Air flows into (and out of) the engine because there's a pressure differential. If we want to increase the flow of air without increasing the size, we need to increase the pressure differential. If we increase the external pressure by a factor of 1 atmosphere, we should double the airflow. Great - double the air, double the power. So - how can we say that a larger turbo will flow the same air but at a lower pressure?

Technically we can't - or we can, but that statement is incomplete. Are we talking CFM flow? Or mass flow? I tend to think in terms of volume- the volume of air I can flow through the throttle body or the volume of air the engine will ingest at a given speed however, it is not the volume of air that is crucial, it is the mass. An M30 living in Minnesota winters will consume the same volume of air at home as it does on holidays in Florida despite the temperature difference (assuming the same atmospheric pressure). It won't get the same air mass however due to the density-reducing effects of Florida's heat.

So - the cooler the discharge temp, or really, the cooler the mass in the intake, the denser it is. The denser it is, the more O2 there will be. More O2, the more fuel we can add and the more tire smoke we can liberate! All at the same boost pressure.


<the rest of you probably concluded all that intuitively - I had to work it out>

[turbodan]

As long as both can flow what the M30 needs them to at x psi, you will have the same amount of air

No you won't. I'm too tired to spell it all out but a 50mm turbo and a 70mm turbo will make very different power on an M30 at the same boost level. Please do some more reading.

This is correct. Given two different turbos, each with very different flow capabilities, they will NOT flow the same air mass at the same boost pressure. Like George, I'm at work and don't have time to spell it out, but don't want anyone to get the wrong idea.

I dont quite agree here. I dont factor compressor outlet temperatures into the flow equation. Its all about the manifold air temps. While it is important to consider compressor efficiency, bigger isn't always better. A compressor running past peak efficiency will still deliver the same air mass as a larger compressor as long as it has enough capacity to maintain the desired boost pressure after the intercooler. The difference will be the amount of exhaust manifold pressure required to drive the compressor to the required speed. A larger compressor running at peak efficiency won't have to work as hard to supply the same air mass as a turbo sized somewhat smaller.

For example, after the intercooler, if two turbos can deliver 1 bar at 70 degrees in the manifold at any given engine speed, the air mass will be the same. Whichever turbo is running at higher efficiency at any given engine speed will be generating less exhaust manifold pressure, which means better scavenging and VE, which will make more power.