[wheela]

Originally Posted by Nathank234

ill quote this from a website that explain it perfectly however its 'Load is an approximation of your motor’s torque output calculated using the the amount of airflow entering the motor, engine RPM, and a scaling constant'

its why in hotter weather a load based tune will request higher load to make up for the lost power from the additional heat. in colder weather, an engine is more efficient so it will lower boost to meet the requested load.

it will technically try and aim for the torque (power is derived from torque) that is requested. however, when we go to a larger turbo, then spool becomes an issue where the tune will request a certain load but the turbo is too large to even get to the PSI that the tune requires in too low of a gear. its like trying to hit full boost in first gear, it will never happen.

in this 3rd gear log before the dyno, when the car does meet the requested load, it made 24psi. however, if the car met the requested load (torque) all the way to redline like the tune is requesting, it will actually require more boost than at the lower rpm as its harder for torque to maintain to redline.

my best guess is the tune is actually over 24psi on the higher gears. but, this is just my best educated guess and im always happy for more information to be provided by others where we can discuss this further

I think this is close, but a little off. %load is just the mass air flow (MAF) being consumed by the engine, but expressed as a percentage of cylinder fill. This provides a way to normalize the airflow per rpm, which is really useful for fuel maps, timing maps and others. For reference, here's a little table I made that calculates the MAF associated with each combination of %load and rpm. I don't know the specific assumptions bmw uses in the load calculation so this is an approximation and not 1:1 accurate. That said, it seems to be accurate to my logs within a few g/sec. That said, torque and load are directly related. Holding all other things equeal, higher load = higher torque.

So the load request shouldn't go up with higher temp, as a certain load% represents the same air mass flow request into the engine. But it does mean the boost target will increase with higher temp - as higher pressure is needed to force the same mass of air into the engine with the warmer, less dense air. And cooler air needs less boost to hit the same load% (air is more dense).

I do agree with needing a higher boost target to hit load% as rpm increases, because the intake valves aren't open as long at higher rpm, so it takes more pressure to push the same amount of air into the cylinder in less time. I also agree with engine having a harder time hitting boost target in lower gears - rpm increases faster in lower gears, so the engine's MAF increases faster, so it's harder for the turbo to keep up with the increasing mass flow.

[wheela]

Originally Posted by Nathank234

Well we can’t say less boost when the post states that the boost was 24 psi tapering down to 22 psi just like the log shows

Since I love data and comparison, here’s something about the previous topic of pure600 and ‘dyno claims’

Pure600 (58/55mm size)
586whp
22psi (at peak power on dyno)
9.5 degrees timing (at peak)
Log:
https://www.bootmod3.net/log?id=66e1...69b7682e629d24

Pure750 (62/62mm size)
645whp
29psi (at peak power on dyno)
15 degree timing (peak power)
Log:
https://bootmod3.net/log?id=650c76e2ae729b2d3b96afb4

Figure out what makes these only 60whp apart

I like this comparison, and think this is a good question. Do we have AFR for these runs we can compare? All else equal, richer AFR will reduce torque, it could be a factor in the differences.

Also, same or different dynos/dyno set up? From the first pure 500 results posted I have to say they are much higher than I thought they were going to be.

[johnung]

Originally Posted by wheela

I like this comparison, and think this is a good question. Do we have AFR for these runs we can compare? All else equal, richer AFR will reduce torque, it could be a factor in the differences.

Also, same or different dynos/dyno set up? From the first pure 500 results posted I have to say they are much higher than I thought they were going to be.

I’m curious why you thought that Pure500 Dynos were higher than expected. The pure500 is basically an improved version of the German TTE460 that ZM2 has posted dynos about several times over the past couple of years. The Pure500 dynos have been right in line with the TTE460.

[wheela]

Originally Posted by johnung

I’m curious why you thought that Pure500 Dynos were higher than expected. The pure500 is basically an improved version of the German TTE460 that ZM2 has posted dynos about several times over the past couple of years. The Pure500 dynos have been right in line with the TTE460.

It seemed like the numbers almost matched ps2 dynos I'd seen in the past. I even saw a speedtech kit with an EFR 7670 that made 530whp on e30. I just didn't expect a stage 1 turbo using a completely stock turbofold and turbine housing to perform so closely to those other options. Even with a good turbine, it's still relatively small and mounted in the small stock volute. I'd be curious what the garret style turbo that the p500 turbine is based on would do for comparison.

[johnung]

Originally Posted by wheela

It seemed like the numbers almost matched ps2 dynos I'd seen in the past. I even saw a speedtech kit with an EFR 7670 that made 530whp on e30. I just didn't expect a stage 1 turbo using a completely stock turbofold and turbine housing to perform so closely to those other options. Even with a good turbine, it's still relatively small and mounted in the small stock volute. I'd be curious what the garret style turbo that the p500 turbine is based on would do for comparison.

I think that Pure did some pretty cool engineering with the Pure500. I think that they figured out that the stock turbofold designed by BMW still had more to offer if they kept the turbine diameter the same (47mm) and just replaced the turbine with a much more efficient GT28 style. I like to say that it’s a high tech nuclear submarine propeller versus a propeller from an outboard motor. I would bet that this helps the Pure500 have instant responsiveness/zero lag, and it probably contributes to it being able to hold power towards redline.

When the Pure500 specs were announced I got some verbal abuse from Shuenk about the turbine being the stock size at 47mm. I think the Shuenk 55+ turbo has a turbine diameter of 52mm, plus a larger turbofold volume. Those things might help a larger turbo, but based on comparison dynos, those things seem to give the smaller 55+ turbo much more lag, without any performance advantage over the Pure500.

Pure did increase the compressor wheel to 52.5mm. I think that the 55+ may be 53mm. In any case the engineering from Pure allowed the Pure500 to have zero lag and a high constant horsepower toward redline. While the 55+ lags and power peaks and drops like a rock. (-220whp in just 1100rpm’s)

When my Pure500 was first installed and I was running it on Bootmod3 OTS tunes, it was obvious how quick it was off the line, but especially how the power stayed high without dropping. While the stock turbo and the Shuenk 55+ both peak and quickly drop off. Then Halim’s custom tune based on his Bootmod3 Stage2+ MultiMap enhanced the Pure500 even more.

[VGSON]

Which boost pipe (turbo to intercooler) are you guys running? More so those pushing 25+ psi…My ftp silicone piping is coming undone even after switching to tbolt clamps. Leaning towards Evo Racewerks.

[johnung]

Originally Posted by VGSON

Which boost pipe (turbo to intercooler) are you guys running? More so those pushing 25+ psi…My ftp silicone piping is coming undone even after switching to tbolt clamps. Leaning towards Evo Racewerks.

I also have the FTP Boost Pipe. No issues. My boost hits about 23psi.

[ericlr1225]

Originally Posted by johnung

I think that Pure did some pretty cool engineering with the Pure500. I think that they figured out that the stock turbofold designed by BMW still had more to offer if they kept the turbine diameter the same (47mm) and just replaced the turbine with a much more efficient GT28 style. I like to say that it’s a high tech nuclear submarine propeller versus a propeller from an outboard motor. I would bet that this helps the Pure500 have instant responsiveness/zero lag, and it probably contributes to it being able to hold power towards redline.

When the Pure500 specs were announced I got some verbal abuse from Shuenk about the turbine being the stock size at 47mm. I think the Shuenk 55+ turbo has a turbine diameter of 52mm, plus a larger turbofold volume. Those things might help a larger turbo, but based on comparison dynos, those things seem to give the smaller 55+ turbo much more lag, without any performance advantage over the Pure500.

Pure did increase the compressor wheel to 52.5mm. I think that the 55+ may be 53mm. In any case the engineering from Pure allowed the Pure500 to have zero lag and a high constant horsepower toward redline. While the 55+ lags and power peaks and drops like a rock. (-220whp in just 1100rpm’s)

When my Pure500 was first installed and I was running it on Bootmod3 OTS tunes, it was obvious how quick it was off the line, but especially how the power stayed high without dropping. While the stock turbo and the Shuenk 55+ both peak and quickly drop off. Then Halim’s custom tune based on his Bootmod3 Stage2+ MultiMap enhanced the Pure500 even more.

Pure500 is just a small turbo without an aftermarket manifold. quick boost, OEM+, cheap

Pure600 is slightly larger and has an aftermarket manifold. It's from the same Chinese factory as N55+'s manifold.


Everything is made in China, we have to admit it. Those turbos are made at around $200-300 raw cost. No special recipe. Pure did more QC(questionable since so many bad cases were reported in the community), assembling, and customer service, I don't mind that either cuz I'm not a fanboy of any of these brands. The real data and modding plan is all I care about.

In this Pure600 case, I have a lot of questions about the hardware list he provided. Also, the tune was running 13.4afr which is for the glory Kabooom run? N55+'s dyno run was 12.6afr E55 fuel. Load actual doesn't make any sense with dyno result either.
Stock injectors miracle? I saw the owner turn on the injection angle parameter to monitor the injector duty cycle, I'm sure CJ is pushing the injection window too. As far as I know, Wedge educated us in the group chat that he always keeps them above 75*-79* minimum to run healthy. The owner is running 70* which I think it's the lowest this parameter can display.
DS2 usually could only handle full E tune + small turbo, 20-21psi mid-rpm range without hpfp dropping pressure. P.S: Turn on "(ram)HPFP duty angle[final]" in BM3 to monitor, max is 109*.

I hate to bring those questions up. I bet everyone wants what they got is the best. Just need more data to learn.

[samsamdar]

Originally Posted by VGSON

Which boost pipe (turbo to intercooler) are you guys running? More so those pushing 25+ psi…My ftp silicone piping is coming undone even after switching to tbolt clamps. Leaning towards Evo Racewerks.

I also had a lot of issues with FTP. I’m gonna swap to DO88 eventually. Just running the stock one for now no issues