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Ok, heres what I have on my 04. Comp Cam 228/228 .588/.588 114 with 918 springs, under drive pulley, SLP longtubes, cats and power flo exhaust and K&N cai. Just bought a FAST 90 intake and TB. Car has a custom tune now and makes 393/371. With the FAST intake and TB should I get new injectors and what brand and size/
 

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Motron 60lb hr seem popular on ls1tech.
 

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I would not go way up to 60# injectors yet unless you have a turbo or supercharger with high boast. You'll need to find out what your injector duty cycle is maxing at on your dyno runs. The rule I've read is once you get past 80% duty cycle you should start looking at upgrading because they start to loose their accuracy in the 90% range.

I'd start at Ford Racing (was SVO) 30# injectors. With the 58psi that we have on the 2004 GTO, these end up giving you about a 36# injector and are a drop in. You'll need to have your pcm modified to reflect the new injector and might also need some tuning for both part and WOT.

I just installed 30# Ford injectors in mine and started tuning it tonight. At my elevation I'm running less power, so could get away with the stockers, but want to be safe when I take it to sea level.
 

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street terrorist
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sorry to hijack but how badly will changing the injectors effect gas mileage?
 

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You can't tell if you need new injectors just by your power and mods. You need to look at your injector duty cycle when tuning. If you are over 90% you may want to bump up a size or two. Yes you can go too big. 60lb/hr are WAY too big for your setup.
 

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As mentioned you can't really guess what injector size you need without monitoring duty cycle, but I would say you prolly need larger than stockers. Get it logged first and find out for sure.

Injectors by themselves won't effect MPG as long as the tune is done right.
 

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Steel Chicken said:
As mentioned you can't really guess what injector size you need without monitoring duty cycle, but I would say you prolly need larger than stockers. Get it logged first and find out for sure.
werd, its getting old around here that people aren't searching
 
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