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Discussion Starter · #1 ·
So I got my truck back and the low to midrange feels pretty weak. New heads, Cams, built bottom end, etc. Are my injectors holding the power back by being maxed out? Should there be more on the table if I upgrade to a 60# injector? Also I think my spark plugs are too cold as the truck misses at cold start then runs flawless when it's warmed up. My brother has the truck out of town so not completely sure what spark plug is in now but I will be switching them out regardless.

Will injectors unleash the beast? Or am I on the wrong track?
What injectors and gap? TR6 plugs?

What about a new fuel pump? Thanks guys
 

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Discussion Starter · #4 ·

· Content Under Pressure
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I thought you couldn't monitor the duty cycle on these trucks?
 

· Panty Dropper
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Discussion Starter · #7 ·
Stock upper and 6# lower pulley.
 

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Stock upper and 6# lower pulley.
Stock blower, stock upper, 6# lower, heads, full exhaust and cams: my builder/tuner recommended to me at this point that I should be upgrading fuel delivery. So I went with twin 255's and matched 60# injectors.

What heads are you using? Cams?

Reason asking: I went with TF 44cc heads and otherwise stock spec on the built short block. Between that and the cams and the long tubes with no cats after going built at first the truck only seemed louder and if faster it was only at the top end. Out of the hole it felt like a dog (or more like not any faster than stock) until one or two more retunes, including throwing at least two cats back on, and a new catback which included an X pipe. It wasn't until after adding the cats and X and the final retune before the middle of the RPM range felt stronger.

Also what is your A/F ratio looking like?
 

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Discussion Starter · #9 ·
Stock blower, stock upper, 6# lower, heads, full exhaust and cams: my builder/tuner recommended to me at this point that I should be upgrading fuel delivery. So I went with twin 255's and matched 60# injectors.

What heads are you using? Cams?

Reason asking: I went with TF 44cc heads and otherwise stock spec on the built short block. Between that and the cams and the long tubes with no cats after going built at first the truck only seemed louder and if faster it was only at the top end. Out of the hole it felt like a dog (or more like not any faster than stock) until one or two more retunes, including throwing at least two cats back on, and a new catback which included an X pipe. It wasn't until after adding the cats and X and the final retune before the middle of the RPM range felt stronger.

Also what is your A/F ratio looking like?
Trickflow heads and comp cams. I have aftermarket cats on now. When you say it felt stronger. Was that after the exhaust change with new injectors?
 

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Discussion Starter · #10 ·
At wot at the high end it goes to 12.25 a/f ratio
 

· Dude
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You still have some meat on the bone and thats actually a little lean for WOT. Should be around 11.5 -11.7.
Havent seen it said yet but do you have upgraded fuel pumps??:smt102 If you do 60lbers you will definitely need new pumps.:smt023:rockon_ford
 

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Put 60's in it. You want to target a max of 85% injector duty cycle. Anything over 90% is hard on the injector driver in the PCM.
I agree that it would like 60# injectors. But although that is good for longevity, it will not solve your power issues.

Not sure who tuned it, but many will use the SCT base files which are soft down low. Lightning specific tuners have created their own files that solve this issue. Also with a built bottom I would be running more pulley.

Jim
 

· Divergent
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Out of the hole it felt like a dog (or more like not any faster than stock) until one or two more retunes, including throwing at least two cats back on, and a new catback which included an X pipe. It wasn't until after adding the cats and X and the final retune before the middle of the RPM range felt stronger.
Pulley to compliment the added airflow from heads and full exhaust + A better tune (more aggressive timing ramp) would've fixed your grunt problem without forking over money to redo the exhaust and adding cats back in. TFs like timing.
 

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Trickflow heads and comp cams. I have aftermarket cats on now. When you say it felt stronger. Was that after the exhaust change with new injectors?
After putting two cats back in (from none and obx lt's and spintech's w/ dr gas x)

At wot at the high end it goes to 12.25 a/f ratio
my WOT and idle A/F after moving the truck from 0-500 elevation to 1500-3000 elevation changed a little. Right now it sits at about 14.8/15.1 when idling and 10.8-11.1 @ WOT. Originally the tune was at 14.7/11.3 +/- .1 A/F (before moving it cross country).

12.25 as i understand it near WOT would be OK, but on the lean side of WOT for S/C application?

For awhile I had issue with the tip in or going from little to no load to light or medium load, it was a little too lean too long in that section. This resulted in some stumbling behavior when attempting to go from say cruising at 60 to very mildly accelerating to 80. The truck would stumble first every time. This has been fixed in a later retune.

Pulley to compliment the added airflow from heads and full exhaust + A better tune (more aggressive timing ramp) would've fixed your grunt problem without forking over money to redo the exhaust and adding cats back in. TFs like timing.
In hindsight I do realize I need to get back to the tuner. When all of the work on my truck was done, that final tune came somewhere around November 2009. I think there were two trucks on the the road in North America with TF heads at the time and mine was one of them. This of course could be wrong, but I was still among the first. I was a guinea pig.

30000 miles later I can tell you that the TF's probably want more timing, and if you're running TF's and cams and have no exhaust back pressure and also find yourself running the stock super charger, its gonna be a pig out of the hole.

I'll probably get it re-tuned after getting the XTi back on the road :)
 
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