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      12-25-2019, 06:21 AM   #76
kern417
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Drives: 2018 440i |2016 340i | 2010 X5
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Quote:
Originally Posted by JD11937 View Post
This is all great information and I appreciate you guys going into the technicalities. Just want to note the vtt turbos are not hybrid.
The GC that they are offering is a hybrid. It's a GT30 wheel that goes into the stock turbofold. The GC+ will be a full replacement of compressor and turbine housing.

Quote:
Originally Posted by enemigo13 View Post
STFT is dependant on fuel you use, add more e85 and STFT will go up. people add fueling/meth because hybrid turbos can give much more boost than stock -> stock fueling is not enough in n55/b58 case. required fueling is calculated not by boost (as air can be hot/cold) but by load (%) - it’s calculated value from boost, IAT, maf readings, etc. and yes for the same load will be same fueling no matter what turbo you use. and yes with the bigger turbo and same load engine will produce more power. PS2 has way bigger turbine wheel than stock N55, and it’s one of the factors why it gives 30-40 hp more than stock turbo with exactly the same tune without any extra fueling. but to use its full potential (1.6 bar 550hp) extra fuel will be needed for sure.
It's not just dependent on the fuel you use. When things happen like vacuum leaks, damaged sensors, or even bigger turbos, it compensates to keep AFRs in check. It's your immediate safety net, because solely calculating fueling based on load will not work with real life scenarios where you see changes in elevations, fuel quality, etc. that is not a part of the load calculation. They were running all the same hardware/fuel, just changed the turbo. The trims changed to compensate. So yeah, it made more power. But it added fuel to prevent engine damage. If it hadn't added more fuel, it would have leaned out.

A lot of people are making 440whp+ on stock fuel system. So making that much with a bigger turbo isn't a surprise. But you can see in the log that he's hitting the fuel limit as pressures drop. Again, it works and makes power. But not safe when you've eaten into your safety net.

Quote:
Originally Posted by IMS-340MP View Post
I read somewhere that a bigger turbo produce cooler charge which explained the higher HP numbers.
It just depends.
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