PD Motor Performance: Maximize Your Output

Hi everyone!

After repeatedly reading about performance increases in PD engines reaching up to 185 horsepower, I decided to do some research on Bosch's website and came across something surprising:

Bosch specifies the maximum power output for the PD system (UIS-P1) used in passenger cars as 25 kW per cylinder.
According to the 'Adam Riese' rule of thumb, for an engine with 4 cylinders, that would be 100 kW, or 136 horsepower.

Therefore, there should be no PD engines with more than 136 horsepower.

Can someone explain this to me?

For those who would like to read more:
Bosch, Technical Training, Diesel Engine Management, Diesel Injection Systems, UIS/UPS, ISBN 3-934584-17-9.

Best regards, Jürgen.

Hi,

These figures are only approximate. Technological progress doesn't stop here either.

I've also read figures of 30, even 35, kilowatts per cylinder.

Hello, fellow diesel enthusiasts.

I checked the Bosch documents you mentioned.
The injection volume is specified as 60 mm³ per stroke.
That would be at 2000 revolutions per minute and a specific consumption rate.
from 200 g/kWh (density 0.83 g/cm³) for just a...
Torque of 285 Nm is sufficient .

Where do the tuners get those 400 Nm of torque from?

best regards, chrigu

That's correct. The 25 kW per cylinder is a specification based on a defined amount of fuel and piston stroke. However, this value of 25 kW refers to the distributor injection system, not the pump/nozzle system.
Chip tuners increase the maximum fuel injection volume/piston stroke, which allows for more power. However, this is limited by the fuel injectors. Since the injection pressure cannot be increased, the injection duration must be extended. However, you cannot inject fuel for an unlimited amount of time. Eventually, the time window for complete combustion of the fuel mass is no longer sufficient, and the limit of power increase is reached. To achieve more power, you would need larger injectors or a modification of the fuel injection pump (e.g., a 11mm pump plunger).

chrigu wrote:

I checked the Bosch documents you mentioned. The injection volume is specified as 60 mm³ per stroke. That would be at 2000 revolutions per minute and a specific consumption rate. from 200 g/kWh (density 0.83 g/cm³) for just a... Torque of 285 Nm is sufficient . Where do the tuners get those 400 Nm of torque from?

Hi.

if there isn't a calculation error in there .

The 81 kW TDI injects a maximum of approximately 40 mg/stroke and, with this, achieves from the factory a nominal torque of 235 Nm.

Therefore, 60 mg should be sufficient for approximately 50% more torque, which would be somewhere around 350 Nm.

I also have that little book as a PDF.

Take a look inside the cover.

bei mir steht da '1. 'Issue 1999'.

Since I got this directly from the intranet, I assume it's the latest version .

btw: what I mean is that there are definitely newer pump elements available now. The 25kW per cylinder is just a guideline.


CU Gremlin.

Hello.
The maximum injection amount is 60mm3 * 0.83gr/mm3 = 49.8mg.

I found the formula in the textbook for automotive engineering.
found.

1000 * effektive Leistung * spez. Consumption.
-------------------------------------------------------------- = Volume in mm3
60 * Engine speed * Fuel density * Number of cylinders

Best regards, chrigu.

chrigu wrote:

Hello. The maximum injection amount is 60mm3 * 0.83gr/mm3 = 49.8mg

.

Hi.

Oh man, I &$%§%(), equated weight and volume .

You are absolutely right.

Hello Ulf,

is half as bad

The question is probably not so easy to answer.
I think there's a connection to what I'm working on.
failed tuning.

Best regards, chrigu.