The power (Literally) of ignition timing
The power (Literally) of ignition timing There has been a lot of discussion lately about how much ignition timing is worth.
The test car is a 2013 ZL1 Auto, 8" lower, 2.6 upper, headers only, injectors, CAI, pump gas, TR8 plugs, boost is 200-206 KPA (14-15 psi)
We had to flash a stock cal file in it, so naturally, we progressed our way into the tuneup.
There are 3 pulls here, 12*, 14*, 16*. AFR is a pretty flat 11.5:1.
These are back to back to back, only down time is the time it took to make a cal change, and the 30 seconds to reflash. The ONLY change to the cal during these pulls was timing. AFR was rich, and I chose to leave it alone.
Louis
The test car is a 2013 ZL1 Auto, 8" lower, 2.6 upper, headers only, injectors, CAI, pump gas, TR8 plugs, boost is 200-206 KPA (14-15 psi)
We had to flash a stock cal file in it, so naturally, we progressed our way into the tuneup.
There are 3 pulls here, 12*, 14*, 16*. AFR is a pretty flat 11.5:1.
These are back to back to back, only down time is the time it took to make a cal change, and the 30 seconds to reflash. The ONLY change to the cal during these pulls was timing. AFR was rich, and I chose to leave it alone.
Louis
I agree on this, another thing I noticed was below 11* the car started losing power FAST, like 25-30whp per degree.
starting at 11*, I gained 14-17whp and about 1mph per degree of timing up to 18* when the gains started to diminish. This was at 12-13# of boost
starting at 11*, I gained 14-17whp and about 1mph per degree of timing up to 18* when the gains started to diminish. This was at 12-13# of boost
Yes, I always pull plugs. I have done enough of these cars, that I know where the limit is before I even start within a few degrees. 16* is childs play, considering Ill run almost double that on C16. I ended up with almost 20* on pump gas with an 8 plug and stock cam with 9:1 compression.
Timing has its limits, like anything else. Always check plugs, always keep good fuel in it if youre pushing the limits, and just be aware. You can melt **** easily if you do not pay attention!!
As for reaching MBT, we will see spark knock before we see MBT, unfortunately, with this setup. Stock, its the opposite, we will see MBT before we see spark knock.
Timing has its limits, like anything else. Always check plugs, always keep good fuel in it if youre pushing the limits, and just be aware. You can melt **** easily if you do not pay attention!!
As for reaching MBT, we will see spark knock before we see MBT, unfortunately, with this setup. Stock, its the opposite, we will see MBT before we see spark knock.
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TECH Enthusiast
Joined: Jul 2008
Posts: 577
Likes: 1
From: League City, Tx
Nice test info!
Thanks for posting.
My last time on the Dyno I was seeing about 15rwhp gain for every 1 degree of timing increase... Up to 17* anyway.. That's where I stopped.. I was seeing similar gains with leaning the AFR every .3 also..(in the high 10 AFR range.)
Thanks for posting.
My last time on the Dyno I was seeing about 15rwhp gain for every 1 degree of timing increase... Up to 17* anyway.. That's where I stopped.. I was seeing similar gains with leaning the AFR every .3 also..(in the high 10 AFR range.)
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If you are REALLY off base timing wise, you could have an incomplete burn, which may affect AFR, but not in this case.
All of the runs ( about 10 total) were all the same. You cant tell which ones were which because they lay on top of each other.
Very nice to see consistent data, it doesn't happen much anymore. Thanks for taking the time to share with us.
did the HP start tapering off enough to end the pull at 6k ish? due to stock cam?
the torque curve seems like this would be crazy on the street, but somewhat predictable since its a broad curve.
did the HP start tapering off enough to end the pull at 6k ish? due to stock cam?
the torque curve seems like this would be crazy on the street, but somewhat predictable since its a broad curve.
Louis, doing some rough math,
for the 12 deg setup to match the power of the 16 deg setup, 3.5-4 psi more boost will need to be added.
which is harder on the engine in your opinion
16 degs and 15 psi, or
12 degrees and 19 psi
for the 12 deg setup to match the power of the 16 deg setup, 3.5-4 psi more boost will need to be added.
which is harder on the engine in your opinion
16 degs and 15 psi, or
12 degrees and 19 psi
TECH Enthusiast
Joined: Jul 2008
Posts: 577
Likes: 1
From: League City, Tx
I also see no real distinguishable difference in AFR from the dyno to the street pulls....My AFR is around 10.9-11.0 on the dyno, and on the street pulls...and the same on race gas (103)+meth vs. 93+meth.... AFR is always pretty constant.... Despite what the internet tells me.
If this was a or 11:1CR setup, Id be lucky to get 12* in it!
Boost and timing can both be detrimental. Its hard to say with such little increases. I would have to say that less boost and more timing would be safer, but more boost, depending on the efficiency of the setup, it may make more power with more boost.
i typically see 25rwhp per degree thru a th400 on the turbo LSX cars i tune.
i lock em out at like 10deg at 8psi and up and push for like 16-18 wherever we wanna stop and then bring it up a degree or two at a shot (depends on where we are)
and it looks just like that, i push for 20+rhwp per degree, then when it makes 5-10 i quit there or go back down a degree.
i lock em out at like 10deg at 8psi and up and push for like 16-18 wherever we wanna stop and then bring it up a degree or two at a shot (depends on where we are)
and it looks just like that, i push for 20+rhwp per degree, then when it makes 5-10 i quit there or go back down a degree.