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#4490201 - 08/16/17 01:41 PM DI + PFI in Ford F-150 Engines
SubLGT Offline


Registered: 01/31/06
Posts: 2646
Loc: Idaho
I thought the purpose of adding port injection to a direct injected engine was to keep the intake valves clean, but it also has other benefits.

http://articles.sae.org/15574/

Quote:
Pete Dowding, Ford Powertrain’s well-travelled chief engineer, told Automotive Engineering the cost of moving all the F-150’s engines to the direct- and indirect-injection layout is justified by the increased fuel economy the design permits—largely because of the higher compression ratios (CR) available from overlaying PFI onto DI. At high load, DI cools the cylinder sufficiently to maintain a high CR without high-octane unleaded. At lower loads, “the DI system bleeds off,” Dowding said, and PFI takes priority, delivering efficient cylinder-fill while still reaping the BMEP benefit of higher compression.

For the newly-downsized V6, the twin-injection system allows a CR increase from 10.8:1 to 12:1. For the heavily-revised 2.7-L turbocharged DOHC V6, the next engine up the F-150 food chain, CR goes from 10:1 to 10.3:1 and for the pickup’s lithe “Coyote” 5-L DOHC V8, CR is boosted from 10.5:1 to 12:1.

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#4490203 - 08/16/17 01:45 PM Re: DI + PFI in Ford F-150 Engines [Re: SubLGT]
09_GXP Offline


Registered: 12/14/10
Posts: 430
Loc: Indianapolis, IN
The intake valve buildup "issues" were largely taken car of early on with slight design changes to the valves. They can actually get pretty dirty before any performance hits are noticed. In these systems the performance benefits are the main advantage while keeping the intake valves clean is a side effect.
_________________________
2017 Miata Global Cup Car #02 - Castol A3/B4 5w30 w/ OEM Fitler
2017 Miata RF - PP 0w20 w/ M1 Filter
2015 F-150 2.7L Ecoboost - PPPP 5w30 w/ MC

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#4490204 - 08/16/17 01:46 PM Re: DI + PFI in Ford F-150 Engines [Re: SubLGT]
Rand Offline


Registered: 08/20/03
Posts: 12638
Loc: NE,Ohio
Interesting

The CR is impressive.. 12:1 and turbocharged???

12:1 NA is pretty good by itself IMO.

My tractor from 1984 is a whopping 6.2:1
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#4490216 - 08/16/17 01:57 PM Re: DI + PFI in Ford F-150 Engines [Re: Rand]
SubLGT Offline


Registered: 01/31/06
Posts: 2646
Loc: Idaho
Originally Posted By: Rand
Interesting

The CR is impressive.. 12:1 and turbocharged???


Non-turbo V8 I think.

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#4490329 - 08/16/17 04:24 PM Re: DI + PFI in Ford F-150 Engines [Re: Rand]
09_GXP Offline


Registered: 12/14/10
Posts: 430
Loc: Indianapolis, IN
Originally Posted By: Rand
Interesting

The CR is impressive.. 12:1 and turbocharged???

12:1 NA is pretty good by itself IMO.

My tractor from 1984 is a whopping 6.2:1


12:1 for the NA engines only, the new 3.3L V6 and the V8. The Ecoboost engines are the 2.7 and 3.5.
_________________________
2017 Miata Global Cup Car #02 - Castol A3/B4 5w30 w/ OEM Fitler
2017 Miata RF - PP 0w20 w/ M1 Filter
2015 F-150 2.7L Ecoboost - PPPP 5w30 w/ MC

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#4492604 - 08/19/17 08:26 AM Re: DI + PFI in Ford F-150 Engines [Re: 09_GXP]
Scdevon Offline


Registered: 09/07/09
Posts: 324
Loc: Rockies
Originally Posted By: 09_GXP
[quote=Rand]

12:1 for the NA engines only, the new 3.3L V6 and the V8. The Ecoboost engines are the 2.7 and 3.5.


N/A compression ratios have been creeping up for a long time with advances in fuel injection and knock sensors.
My 2003 Mustang Mach 1 has 10.1:1 which I thought was great in 2003. Smog cars in the 1970s had as low as 7:1 in some cases.

Compression ratios fell off of a cliff (cam specs too) around 1973 because it was the only way to get engines designed in the 1960s to pass 1970s emissions standards, but lately compression ratios have been eye-popping good !!
_________________________
2003 Mustang Mach 1. 32V 4.6 Liter. Motorcraft Syn Blend 5W30
1970 Mustang Convertible 302-2V Auto (Stock) M/C 10W30
1970 VW Beetle 1600 DP

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