[e.n335]

Originally Posted by faster335

No biggie, just trying to help. In his post he said it ran 6-8psi, which is what I see on my gauge. 6psi in the midrange, around 8psi when it gets over 4500rpm. I haven't noticed any boost spikes stock.

I think your friend is a lost cause.

Read post #25 please.

[e.n335]

Originally Posted by faster335

I read it as 13.5psi procede - 8.8 psi stock = 4.7psi over specification, plus up to .2bar for altitude correction. If everything works as it should I'd expect a maximum boost of 16.44psi in extreme altitudes.

From what I understand though the procede is around 12psi over stock not 13.5 (that is probably just a spike to get you moving along when you nail it), and I know the factory boost doesn't hit 8 until around 4500rpm. At any given time you might be running 6-7psi over stock in the midrange and closer to 4psi over stock up top. That was my only point. If you look at the dyno my reasoning makes sense, you don't get 100#ft gains from 1.9psi... it takes closer to 7-8 off a boost spike.

There is no room for interpretation when you read this thread. The discussion has been about the specifications of the turbos. Learn to read.

[RiXst3r]

Originally Posted by e.n335

AFAIK you should be able to google for "bmw 335i 0.8 bar" IMHO

nice one eugen

[TinkySD]

As I see it the facts are these:

1) The turbos are rated for .8 bar(including altitude correction) That means up to .8 bar they are manufactured to be completely reliable; meaning they are designed to be able to run .8 bar all the time for those customers who live at altitude

2) In stock trim you'll more than likely not see over 8.5 PSI at sea level or 10.5 at altitude.



So it would seem just an agruemant of semantics. E.N is correct in that his data loggin shows max boost within 2 PSI of the spececified ability of the turbos. The other is correct in that it is higher by 4-5 psi or so at sea level but within 2 psi of the spec'd ability of the turbos.

[e.n335]

Originally Posted by TinkySD

As I see it the facts are these:

1) The turbos are rated for .8 bar(including altitude correction) That means up to .8 bar they are manufactured to be completely reliable; meaning they are designed to be able to run .8 bar all the time for those customers who live at altitude

2) In stock trim you'll more than likely not see over 8.5 PSI at sea level or 10.5 at altitude.



So it would seem just an agruemant of semantics. E.N is correct in that his data loggin shows max boost within 2 PSI of the spececified ability of the turbos. The other is correct in that it is higher by 4-5 psi or so at sea level but within 2 psi of the spec'd ability of the turbos.

The nice thing of a piggypack is that you can adjust the boost pressure in any rev range to the value you like it to have. Beside timing and fuel. That is what the engine controls to run smooth, not hotter than stock, avoids knocking and provides quite good power gains in case of the PROcede. 500+ are sold, not one single known engine hardware problem up to now. Some drive really hard and race the car. I will drop you a note when I will have my first 100k miles on the engine .

p.s. In fact the turbos are rated for 1.1 bar ( 16 psi ) but that's a different story and I think this boost pressure would result in a problem without lowering the engines compression ratio.

[BoostedBMW]

You guys are basically saying the same thing, but you are looking at it from two different perspectives. While Eugen is stating how much harder the turbo's are working over what they are made to do under the harshest stock conditions, faster335 is looking at it in terms of how much more boost the engine is being fed over stock (at sea level, which is also the way that I would view this). Both of you guys are correct, your just seeing it from two different sides, and arguing for different things. Eugen is talking about turbo life, and faster335 is refering to engine life. Now lets all just play nice.

[Lee Rambler]

has it been confirmed what MHI turbos are indeed in the car? In another post about upgrading the turbos there are mixed reports. If it is indeed a TD04-9G, I'm not sure that 16psi is reliable. The turbo will run out of snuff at the top end at much lower boost pressures than that (ie, it is already happening).

the other thing that needs to be considered when looking at how much more boost is being used by the piggybacks is that it is the difference in absolute manifold pressure that matters. Yes the car will run higher boost at altitude, but it isn't higher absolute pressure. This is why it makes the same power on "more" boost. Because of this I would agree with faster335 in the amount of boost difference of a piggybacked car and a stock car, at least as far as stress on the rest of the motor is concerned. He is also correct in his statement about that difference being the change in maximum boost. the boost throughout the rpm range is changed dramatically as well though - there are points in the midrange that the boost is much higher than stock as faster335 pointed out. this is where the big torque gains are being had. with all of this said, I still personally think it is perfectly safe. It isn't going beyond the limits of the turbo at those rpm's - it just creates a less linear power band, which is part of what makes the car feel like it has more "lag". it's still making the same power down low, it is just making more power in the midband. when designing the car, bmw was shooting for a smooth power band akin to their V8 engines. that's why the choose smaller turbos that spool faster and that's why they designed the engine management (including boost management) the way they did.

[sflgator]

Originally Posted by Lee Rambler

has it been confirmed what MHI turbos are indeed in the car? In another post about upgrading the turbos there are mixed reports. If it is indeed a TD04-9G, I'm not sure that 16psi is reliable. The turbo will run out of snuff at the top end at much lower boost pressures than that (ie, it is already happening).

the other thing that needs to be considered when looking at how much more boost is being used by the piggybacks is that it is the difference in absolute manifold pressure that matters. Yes the car will run higher boost at altitude, but it isn't higher absolute pressure. This is why it makes the same power on "more" boost. Because of this I would agree with faster335 in the amount of boost difference of a piggybacked car and a stock car, at least as far as stress on the rest of the motor is concerned. He is also correct in his statement about that difference being the change in maximum boost. the boost throughout the rpm range is changed dramatically as well though - there are points in the midrange that the boost is much higher than stock as faster335 pointed out. this is where the big torque gains are being had. with all of this said, I still personally think it is perfectly safe. It isn't going beyond the limits of the turbo at those rpm's - it just creates a less linear power band, which is part of what makes the car feel like it has more "lag". it's still making the same power down low, it is just making more power in the midband. when designing the car, bmw was shooting for a smooth power band akin to their V8 engines. that's why the choose smaller turbos that spool faster and that's why they designed the engine management (including boost management) the way they did.

Even with the PROcede and another 60+ WHP and 90+ lb.-ft RWTQ, there's very little turbo lag (a little more noticeable, but still less than 1 sec. before kick-in).

[cn555ic]

I love my car and her new friend....P