05-31-2020, 10:40 PM | #1 |
Drives: 2018 Camaro 1SS Blue Join Date: May 2019
Location: Kernersville, NC
Posts: 55
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Knock Retard Question
Guys - looking for an understanding here please. When my 2018 SS was basically stock with E85 and CAI, I got a mail order tune for it. It seemed to work quite well. When I was logging, I noticed timing would be 27.5-28 degrees WOT with zero knock across the board.
Now I have the car much more modified (see sig) with LT4 injectors and hpfp. My current tuner had it set at 25 degrees and it would get like .1 retard now and then. I raised that to 26 degrees and saw a couple of cells at .4 up to 1.5 degrees retard. How can I be much more modified, same fuel etc but have to run 2-3 degrees less timing? Trying to understand how this works - thanks!
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CNC Ported 12:1 Heads/Kooks 1 7/8"/Hellion custom cam/Atomic MSD/Tony Mamo V2 PTB/K&N CAI/E85/All LT4 Fueling/Mystery Axle-back/Gap Juice
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06-02-2020, 07:18 AM | #2 |
Drives: 2018 Camaro 1SS Blue Join Date: May 2019
Location: Kernersville, NC
Posts: 55
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No suggestions? Actually, I did think of something. I now remember reading the datasheet on these ported heads - they are 12:1 compression so perhaps that could account for not being able to run as much timing as the stock 11.5:1 heads. Thoughts?
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CNC Ported 12:1 Heads/Kooks 1 7/8"/Hellion custom cam/Atomic MSD/Tony Mamo V2 PTB/K&N CAI/E85/All LT4 Fueling/Mystery Axle-back/Gap Juice
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06-02-2020, 08:17 AM | #3 |
@texan.1le
Drives: '18 Camaro 1SS 1LE, PDR Join Date: Jun 2018
Location: Temple, TX
Posts: 182
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I'm willing to bet the E85 you are getting (I'm assuming it is pump E85) simply just isn't quite "good enough" for that extra .5 worth of compression. You may have found the limit for the fuel you have if it was the exact same as when it was used on your first tune, or the quality of the E85 fuel you have may have gone down since you swapped your heads.
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'18 1SS 1LE - "Mongoose"
'15 Malibu 2LT - daily |
06-02-2020, 09:51 AM | #4 | |
Drives: 2018 Camaro 1SS Blue Join Date: May 2019
Location: Kernersville, NC
Posts: 55
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Quote:
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CNC Ported 12:1 Heads/Kooks 1 7/8"/Hellion custom cam/Atomic MSD/Tony Mamo V2 PTB/K&N CAI/E85/All LT4 Fueling/Mystery Axle-back/Gap Juice
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06-02-2020, 09:04 PM | #5 |
Drives: 18 Camaro LS M6 Join Date: Apr 2019
Location: NH
Posts: 698
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Dude, accept the new normal for what it is, be glad your not a turbo owner. after a "bunch of mods" and your looking at .5 ? And no your not losing HP it just doesn't equate that way. timing does not automatically mean HP if you've increased VE by any means.
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. . NFG M6 2T Mishimoto Hot side pie | ZZP Catted DP | KN Drop in | Borla - Sport Tour | Apex Arc 8 - square | Wookster Tuning+ | Flex Fuel Last PB 4.8, 13.2@106 |
06-03-2020, 08:01 AM | #6 |
Drives: 2018 Camaro 1SS Blue Join Date: May 2019
Location: Kernersville, NC
Posts: 55
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Thanks, just trying to learn the ropes. A lot has changed since my LS tuning days.
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CNC Ported 12:1 Heads/Kooks 1 7/8"/Hellion custom cam/Atomic MSD/Tony Mamo V2 PTB/K&N CAI/E85/All LT4 Fueling/Mystery Axle-back/Gap Juice
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06-04-2020, 02:11 AM | #7 |
Drives: 2017 Camaro SS 1LE Join Date: Apr 2019
Location: Chicago burbs
Posts: 36
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With the added compression and higher overall airflow with heads/cam/ intake, cylinder pressure is higher and less timing is needed.
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