Boost pressure on 88 951
06-16-2002, 07:41 AM
#1
Track Day
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Join Date: Jun 2002
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Boost pressure on 88 951
Hi,
My stock boost gauge always indicates about 1.55bar under full load in 1st, 2nd and 3rd. I always thought this had to be something like 1.8bar under stock conditions.
I thought i had a leak or something so i checked in the manual and saw this:
As i have a M44.51 engine, it seems to be fine. The strange thing is, i can have that 1.75bar under full load in 4th and 5th at rpm's like 4000rpm. How is this possible??
My stock boost gauge always indicates about 1.55bar under full load in 1st, 2nd and 3rd. I always thought this had to be something like 1.8bar under stock conditions.
I thought i had a leak or something so i checked in the manual and saw this:
As i have a M44.51 engine, it seems to be fine. The strange thing is, i can have that 1.75bar under full load in 4th and 5th at rpm's like 4000rpm. How is this possible??
06-17-2002, 05:52 AM
#2
Race Director
Differing boosts in different gears is perfectly normal.
One factor is the amount of load you have on the engine. Lower gears put a lower load, thus less exhaust gases are present to power the turbo, leading to lower boost.
Another factor is the air requirements. The CFM ingested by the engine rises quicker in the lower gears and the turbo has to provide larger volume increases of air quicker in the lower gears.
One factor is the amount of load you have on the engine. Lower gears put a lower load, thus less exhaust gases are present to power the turbo, leading to lower boost.
Another factor is the air requirements. The CFM ingested by the engine rises quicker in the lower gears and the turbo has to provide larger volume increases of air quicker in the lower gears.