Correct Flow Rate of PTE 550cc injectors

tte

Breaking In - in progress
Mar 30, 2005
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Northern California
Hi guys,

What is the correct rating for the PTE 550cc injectors at 90% duty cycle?

I read Weezl had his Ptes at 50 lbs @90%...

Cheers,
Roy
 

starscream5000

Senior VIP Member
Aug 23, 2006
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I think it's 80%, because most injectors max out at 80% duty cycle. Anyways, 90% is 495cc's or 47.1429 lbs/hr. At 80% it's 440cc's or 41.9048 lbs/hr.

Calculations for lbs/hr came from: http://www.racetep.com/rc2.html

And of course, just multiply the number of cc's in the injector by the % of duty you are wanting to run them at ;).
 

aljordan

LEADED FUEL ONLY
Jul 14, 2005
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550 cc injectors flow 550ccs of fuel wide open. Just like the stock injectors are 440s and are tested at wide open as per the TSRM.

To find what a 550 will flow at 90% DC, just multiple 550 by 90%.

Some additional tech info regarding injectors written by a dude at RC Engineering. Just for the people using search out there..

http://www.suprasonic.org/public_html/sonictech/fuel_injectors/RCtech.html
 

Facime

Leather work expert
Jun 1, 2006
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I called and talked to PTE directly to find out what the markings on the side of my injectors meant. The tech that I spoke with said that PTE tests their injectors at 90% duty cycle and they flow (in my case) between 50.5 lbs/min and 50.8

How that would be compared to other injectors that may be tested at 80% duty cycle...well you do the math.
 

Facime

Leather work expert
Jun 1, 2006
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awe crap yes it does and I forget what they said it was. Off the top of my head I think 43lbs? isnt there an industry standard?
 

tte

Breaking In - in progress
Mar 30, 2005
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Northern California
How do they test it?

Do they have a setup for the injectors and a electronic control that runs and varies the duty cycle from 0% - 100% or it is rpm based?

Cheers,
Roy
 

Nick M

Black Rifles Matter
Sep 9, 2005
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So this would make the PTE injectors too big for the LEX/550 upgrade, knowing Toyota's test is at 100% for 15 seconds. I wondrer how many have had problems using this 580 injector and didn't know it wasn't a 550.
 

Dirgle

Conjurer of Boost
Mar 30, 2005
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The original design for the lex/550 was a direct replacement with out having to fiddle. Of course over time people added things to tune the pig rich state out of the stock fuel maps. But the original design and calculations were made for a "drop and go" upgrade.
 

Nick M

Black Rifles Matter
Sep 9, 2005
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theWeezL said:
Nick, isnt that what a wideband and SAFC is for? Or an AFPR for that matter.

I was going to say no. The SAFC was simply accomidating the incorrect injector size, now that we see in hindsight.

The factory 1UZFE injectors are calibrated to the anticpated airflow and meter size of the engine.
 

aljordan

LEADED FUEL ONLY
Jul 14, 2005
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Indianapolis, Indiana
www.apeserver.com
People.... if you have 550cc injectors.. they flow 550cc's at 100% duty cycle, and 43.5 psi. The pressure is an industry standard, as is the sizing.

WHen you have an injector "tested" at 80%, that means they run the injector at 80% to ensure it'll work. It DOES NOT mean it flows 550ccs at 80% duty cycle. 550s should flow around 440ccs at 80%.