Injector Timing - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Deutschezl1 · 03-05-2020, 04:28 PM

Trying to build my understanding of tuning injector timing but hitting a snag. I'm looking for the stock cam specs for a 2013 ZL1. Cam PN#12623064

Specifically what is the advertised intake/exhaust duration on this cam?

Also what is the intake center-line?

Any and all help is appreciated.

Big Biscuits · 03-11-2020, 01:04 PM

I wouldn’t look too much into the stock injection timing, GM does a good job there. Look at it when you install a new cam and supporting mods. Remember, if you change injection timing, your fueling will be off and you will need to retune.

shibbs · 03-11-2020, 02:17 PM

Injector timing is much more a thing when you're talking about a direct-injected engine. Our port injection is usually just fine from factory.

RobZL1 · 03-11-2020, 04:02 PM

You can definitely use it to get rid of raw gas smell at idle with a cam. I can vouch for that one personally.

There are mixed opinions, some with data and some without, regarding injector timing throughout the rev range. There are many good threads over on the hpt forum on the topic. Most end up delaying timing. Max EOIT is usually suggested at no closer than 30-45 degrees prior to EVC event.

dreksnot · 03-11-2020, 04:54 PM

I've messed around with the EOIT on my LS3 with BTR Stg 3 turbo cam and thought I had it pretty good. Now, I've tried with the LSX and a custom grind (probably stg 3-ish) and I'm not sure what kind of advantage/disadvantage I've received. I don't have smelly gas exhaust. My mileage sucks (not sure if that's me, the 427cid, the cam or the EOIT settings). I've played with some Excel spreadsheet calculators (they're in Greek) and tried to dial in the timings. I'm not sure if I did any good or made things worse. I might should resort back to stock settings to compare...

Big Biscuits · 03-11-2020, 09:46 PM

I used the calculators and I think it is dead nuts on. No cats, no smell, revs faster, easier to dial in -1 to-2% trims. I bet it’s much harder on a large cube engine. I did find using the temp table along with the boundary and zero out the rpm did the trick. The spreadsheet is a work of art! I would love to see how those complicated calculations are made.

Deutschezl1 · 03-12-2020, 03:04 PM

Thanks guys for all the helpful info. Found a couple good threads on the hptuner forums that helped me make more since of it.

03-11-2020, 01:04 PM	#2
Big Biscuits Drives: 2010 1SS LS3 Join Date: Aug 2019 Location: Waxahachie, TX Posts: 280	I wouldn’t look too much into the stock injection timing, GM does a good job there. Look at it when you install a new cam and supporting mods. Remember, if you change injection timing, your fueling will be off and you will need to retune. __________________ 2010 CGM 1SS 408/4L80E/ZL1 Vortech V-13 94C

03-11-2020, 04:02 PM	#4
RobZL1 fo'shizZL1 Drives: 2017 ZL1 Join Date: Aug 2017 Location: ATL Posts: 1,794	You can definitely use it to get rid of raw gas smell at idle with a cam. I can vouch for that one personally. There are mixed opinions, some with data and some without, regarding injector timing throughout the rev range. There are many good threads over on the hpt forum on the topic. Most end up delaying timing. Max EOIT is usually suggested at no closer than 30-45 degrees prior to EVC event. __________________ 2017 ZL1 M6 Black \| Maggie 2650 // 103TB // Big Gulp // CSP LT's & Ultra Cats // BMR MM // BC Forged KL13 Mods being installed- oil pump, cam, ported heads, dual in-tank, Goliath and XDI, corn, etc., etc.

03-11-2020, 04:54 PM	#5
dreksnot Served USN - Atomic Chimp Drives: 2021 Camaro ZL1 1LE A10 (stock) Join Date: Jul 2012 Location: Fort Collins, CO Posts: 1,706 View My Garage	I've messed around with the EOIT on my LS3 with BTR Stg 3 turbo cam and thought I had it pretty good. Now, I've tried with the LSX and a custom grind (probably stg 3-ish) and I'm not sure what kind of advantage/disadvantage I've received. I don't have smelly gas exhaust. My mileage sucks (not sure if that's me, the 427cid, the cam or the EOIT settings). I've played with some Excel spreadsheet calculators (they're in Greek) and tried to dial in the timings. I'm not sure if I did any good or made things worse. I might should resort back to stock settings to compare... __________________ > > 2021 Camaro ZL1 1LE A10 > > Past Builds: 2013 Twin-Turbo LSX434 M6 - 1,359rwhp daily

03-11-2020, 09:46 PM	#6
Big Biscuits Drives: 2010 1SS LS3 Join Date: Aug 2019 Location: Waxahachie, TX Posts: 280	I used the calculators and I think it is dead nuts on. No cats, no smell, revs faster, easier to dial in -1 to-2% trims. I bet it’s much harder on a large cube engine. I did find using the temp table along with the boundary and zero out the rpm did the trick. The spreadsheet is a work of art! I would love to see how those complicated calculations are made. __________________ 2010 CGM 1SS 408/4L80E/ZL1 Vortech V-13 94C

03-05-2020, 04:28 PM	#1
Deutschezl1 Drives: Zl1 Camaro Join Date: Nov 2019 Location: Germany Posts: 71	Injector Timing Trying to build my understanding of tuning injector timing but hitting a snag. I'm looking for the stock cam specs for a 2013 ZL1. Cam PN#12623064 Specifically what is the advertised intake/exhaust duration on this cam? Also what is the intake center-line? Any and all help is appreciated.

03-12-2020, 03:04 PM	#7
Deutschezl1 Drives: Zl1 Camaro Join Date: Nov 2019 Location: Germany Posts: 71	Thanks guys for all the helpful info. Found a couple good threads on the hptuner forums that helped me make more since of it.