*NOW BOOKED FOR 2024* Transitmania 15 @ Santa Pod 19th to 21st July 2024 *ALL DETAILS HERE*


turbo boost pressure

Transit Mk3, 4 & 5(smiley front) Forum. All Transits 1986 - 2000

Re: turbo boost pressure

Postby Jim Archer » Fri Mar 16, 2018 10:26 am

I do agree in part.

If you are asking the motor to compress air at a higher pressure, you have to give proportionally more fuel to achieve any gain, otherwise you lose out to pumping losses.

Bear in mind that diesel exhaust flow, and thus boost pressure are entirely fuel dependant, more fuel = more flow. Run the motor at part load and you only get part of the full boost pressure, you don't run at max boost until there is enough exhaust flow to spool the turbo up to speed.

The thing to watch with non intercooled systems is that the exhaust gas temperature (EGT) can increase pretty quickly and cause damage to down stream compenents - exhaust valves, turbine wheel and bearings, turbo mounting fixings, etc.

In answer to why run 20Psi - 'cos it was bloody good fun 8)

Jim
Mk7 140 Jumbo - Vantunered.
289,000 and counting.
Jim Archer
Transit Fanatic
Transit Fanatic
 
Posts: 3434
Joined: Sat Sep 29, 2007 6:45 pm
Location: Southampton

Re: turbo boost pressure

Postby vanfox » Fri Mar 16, 2018 1:38 pm

Where do you measure the EGT and what do you use? Yes 20 psi was fun.......
vanfox
Transit Fanatic
Transit Fanatic
 
Posts: 2164
Joined: Mon Sep 04, 2006 2:41 pm
Location: Warrington

Re: turbo boost pressure

Postby cherniy_chack » Fri Mar 16, 2018 5:06 pm

The fundamentals of thermodynamics speak of the reversibility of compression and expansion of gases, theoretically the energy costs for gas compression and energy release during its expansion are equal, but mechanics interfere.
The diagram of the gas distribution of the Ford Transit 2.5 D engine indicates that air compression occurs over 180-27 = 153 angular degrees.
Expansion of combustion products-only 180-57 = 123 angular degrees.
This is without taking into account the friction losses in the engine mechanism, which increase with increasing pressure in the cylinder.
2018-01-04 (7).png
You do not have the required permissions to view the files attached to this post.
User avatar
cherniy_chack
Transit Devotee
Transit Devotee
 
Posts: 1240
Joined: Sun Jan 14, 2018 10:49 am
Location: Kiev is the capital of Ukraine

Previous

Return to Mk 3, 4 & 5 - Second Generation Transits



Who is online

Users browsing this forum: Majestic-12 [Bot]

This site contains affiliate links for which we may be compensated.