LQ4 - Big Cam Tuning

[stilsonian]

Neighbor put an LQ4 in place of his LM7 in a 2003 Silverado. He slapped a big cam (specs below) in it with no other mods and asked me to come tune it. I'm going to look at it this weekend, but based on the cam card, it looks like I have my work cut out for me. Any help on getting a tune close before going over there will be greatly appreciated. Thanks in advance!

Lift: 0.595"/0.595"
Duration @ 0.050": 234?/277?
Advertised Duration: 295?/336?
Lobe Separation: 107?

Injectors are stock 6.0 replacement injectors - TRQ FLA60337

Base tune attached.

Silverado_stock.hpt

[blindsquirrel]

Your search - FLA60337 - did not match any documents.

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'stock 6.0 replacement injectors' only narrows it down to about 8 or 9 possibilities. If you meant to say 'stock 2003 6.0 replacement injectors' then those are only 25lb-hr and not big enough for the power that combo would make. If the truck has a returnless fuel system those are only good for about 360 HP, at the crank. A 2003 truck should have a return style system, but your file is set up for returnless.

[SiriusC1024]

They go in the trash.
https://autobuffy.com/product/2004/g...37/UC-10435705

Get some Gen IV injectors.
https://forum.hptuners.com/showthrea...l=1#post766924

[edcmat-l1]

Cam needs to come back out and go in the trash too. If those specs are right it'll never run right.

[bk2life]

Cam needs to come back out and go in the trash too. If those specs are right it'll never run right.

especially in a big heavy truck

[gtstorey]

But it will sound good.

[edcmat-l1]

I'd like to believe the 277 exhaust duration is a misprint. If it's not that's just ridiculous. That much duration is typically solid roller type stuff and no one runs a 43 degree split. So, if it's a misprint which I believe it is, even if the real duration is 247, a 234/247/107 LSA is still a terrible choice for an otherwise bone stock truck. This is the kind of stuff I turn away. "Nah man, your combo is just dumb. Sorry". LOL

[abc]

Not to mention piston to valve clearance with a split like that!

[stilsonian]

Sorry guys, he sent me a misspelled injector PN - it's FIA60337

Below is a link to the cam. Not a misprint, unfortunately.

https://www.jegs.com/i/JEGS/555/200584/10002/-1

I'm tempted to walk away. Really good guy, but the Jegs counter guy told him this was a rowdy cam good for a stock truck. Sadly, he believed him. Just found out it's on a stock TC as well, so even if I could get it to idle in P/N, there's no way it's going into gear.

He did inform me that he has the 2006 6.0 ECU in it and the truck is a late 2003, so it was returnless. So, the returnless system is correct.

[SiriusC1024]

Throw the Jegs guy in the trash.

[2xLS1]

He did inform me that he has the 2006 6.0 ECU in it and the truck is a late 2003.

06 calibration is not compatible with 03-05 ETC hardware.

[C6_Will]

It'd be faster with the factory camshaft.

[RDF1]

Sorry guys, he sent me a misspelled injector PN - it's FIA60337

Below is a link to the cam. Not a misprint, unfortunately.

https://www.jegs.com/i/JEGS/555/200584/10002/-1

I'm tempted to walk away. Really good guy, but the Jegs counter guy told him this was a rowdy cam good for a stock truck. Sadly, he believed him. Just found out it's on a stock TC as well, so even if I could get it to idle in P/N, there's no way it's going into gear.

He did inform me that he has the 2006 6.0 ECU in it and the truck is a late 2003, so it was returnless. So, the returnless system is correct.

This is the perfect example of when to explain to your neighbor to stop before it gets any worse. Im sure you can get it to fire up and halfway idle but your working with chineseium injectors and a cam that will need a 4500-5000 stall. Just tell him to count his losses and buy a more suited camshaft and GM injectors.

[edcmat-l1]

The cam specs are just dumb. Wonder what jackass came up with those specs.

[SiriusC1024]

The cam specs are just dumb. Wonder what jackass came up with those specs.

Elgin lol

[RDF1]

Had a guy tell me he bought a cam and thought the specs were way off and remembered this thread..
Its a Elgin E-1255-P after looking around.