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[Z06] LT Headers + Vararam = what injector

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Old May 9, 2016 | 12:16 PM
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Default LT Headers + Vararam = what injector

I just installed LT headers and Vararam while getting the car tuned over the weekend. All said and done, the car does pull much better. The tuner stated that in the higher rpm's and WOT, the injector cycle duty was right at 97 percent. Is this what others have encountered? Now considering larger injectors, but wanted to hear from the experts first. Didn't think that these light bolt ons and a tune would necessitate the need for larger injectors.

Thanks!
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Old May 9, 2016 | 01:14 PM
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You don't need larger injectors. If you want to upgrade them in anticipation of more modifications down the road, great...but I personally wouldn't spend the money.
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Old May 9, 2016 | 01:50 PM
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I have a vararam and am adding LT's now, Im getting a tune for them but keeping stock injectors. Ive never heard that just these two basic mods required bigger injectors?
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Old May 9, 2016 | 02:43 PM
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Thanks for the comments. I was hoping new injectors were not needed and wanted to verify. Looks like new injectors can wait. That 97% cycle is what had me concerned.

MY03C5Z - you will love the improvement. Just be ready for to pull from a great deal of patience while installing the LT's. If you don't mind, when you get the tune, can you ask about the injector duty cycle? Want to see if the 97% is fairly consistent.

Last edited by Andrew; May 9, 2016 at 02:45 PM.
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Old May 9, 2016 | 03:23 PM
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is longtubes and an intake all you have done??... my stock injectors were at 95% duty cyle with intake, headers, and cam making roughly 420rwhp... maybe the car was tuned really fat and that accounts for the high duty cycle
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Old May 9, 2016 | 03:41 PM
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Originally Posted by neutron82
is longtubes and an intake all you have done??... my stock injectors were at 95% duty cyle with intake, headers, and cam making roughly 420rwhp... maybe the car was tuned really fat and that accounts for the high duty cycle
Yep, that is all that was done. It is not running fat, AF hovers around 13.0 - 13.1.
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Old May 9, 2016 | 03:48 PM
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13-13.1 wide open or idle/cruise?... still seems too high of a duty cycle for those mods in my opinion

Last edited by StingrayRebel; May 9, 2016 at 03:48 PM.
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Old May 9, 2016 | 04:06 PM
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Originally Posted by neutron82
13-13.1 wide open or idle/cruise?... still seems too high of a duty cycle for those mods in my opinion
WOT. Idle / cruise it leans out a bit. I agree, was surprised at the results. I have owned the car for 4 years and cannot attest to what was done prior to me purchasing the car, but there is no signs of anything else ever being done to it. Could the computer be throwing false duty cycle readings? I agree, was unexpectedly high and seemed on the high side to me as well.
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Old May 9, 2016 | 07:21 PM
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Originally Posted by Andrew
Thanks for the comments. I was hoping new injectors were not needed and wanted to verify. Looks like new injectors can wait. That 97% cycle is what had me concerned.

MY03C5Z - you will love the improvement. Just be ready for to pull from a great deal of patience while installing the LT's. If you don't mind, when you get the tune, can you ask about the injector duty cycle? Want to see if the 97% is fairly consistent.
Got the headers on this weekend, just have to finish the h pipe and waiting on some new header bolts to finish it up. Was just going to go with a mail order tune from ECS. Yeah, can't wait to fire it up this weekend
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Old May 9, 2016 | 07:34 PM
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maybe check the part numbers on the injectors and make sure they weren't swapped out before you got the car... if everything else checks out then if you do any more mods new injectors should be on the list as well
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Old May 9, 2016 | 08:32 PM
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Might try checking the fuel filter and running some sort of top end cleaner/injector cleaner if you haven't done that already
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Old May 9, 2016 | 10:24 PM
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Lt's and vararam here on my 03z. When tuned last week tuner said I was around 80% on my stock injectors.
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Old May 10, 2016 | 08:57 AM
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Originally Posted by bwill03z
Lt's and vararam here on my 03z. When tuned last week tuner said I was around 80% on my stock injectors.

That or slightly lower is what I typically see here. 97/98 injectors are a little smaller though.
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Old May 10, 2016 | 09:42 AM
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Thanks everyone for the info. Good point on injectors. I will find the numbers on the injectors and let you know. I do not believe that they have been changed, but you never know. 10 years of previous ownership, could have been changed.
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