What is limiting timing? - Dodge SRT Forum
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post #1 of 49 (permalink) Old 12-03-2016, 05:17 PM Thread Starter
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What is limiting timing?

I spent all day trying to dial in the tune to get the most timing I can. No problems until I hit 21*. I'm on 91 octane, but I'm also spraying 250/cc 50/50 meth. Why can't I get past 21*? I've seen other setups where they are running 30* timing with meth. Is that just where it's going to be for 22psi? AFR's are right around 11:1.

Are my expectations just off? I'm under the impression I can run around 25*-30* with the meth. What does a BWS on 91 normally run for timing?

As far as I can tell, the engine is fine. Compression is 145 across the board and I put the PCV on a vented CC. Already replaced knock sensor and everything else I can think of.

I spent quite a bit of time reading up about fuels, detonation, plug gaps, EGTs, exhaust pulses, etc but so far I can't think of what I can do to improve the situation.

2005 ACR
Duster360 custom tune, 16G BWS, Fully bored TB, Meth Injection,1025cc injectors, over-sized valves,HKS BOV, AGP WGA, 3 bar map/tip, Thermal R&D 3" TBE, AEM CAI, AEM wideband, MPx catch can, fuel pump rewire, booger shifter bushings, solid engine mounts, energy suspension bushings.

2014 Genesis Coupe 3.8 R-Spec
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Last edited by titan2782; 12-03-2016 at 05:20 PM.
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post #2 of 49 (permalink) Old 12-04-2016, 07:57 PM
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Many many variables here and I'm sure tuners with more seat time than I will chime in.

With my set up I would consistently get 27.0/27.5* @ 5500 RPM

In my opinion, start with good fuel. I've had good luck with this product RACE GAS | Racing Fuel Concentrate

Good Luck!!!

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post #3 of 49 (permalink) Old 12-04-2016, 08:05 PM Thread Starter
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well fuel isn't a solution. I already use chevron 91 exclusively in all my vehicles.

I made this post in frustration, but today I figured out the issue which that I have a cracked exhaust manifold. So that's what the problem is. Already pulled it off, going to get it welded up and then I should be good to go.

2005 ACR
Duster360 custom tune, 16G BWS, Fully bored TB, Meth Injection,1025cc injectors, over-sized valves,HKS BOV, AGP WGA, 3 bar map/tip, Thermal R&D 3" TBE, AEM CAI, AEM wideband, MPx catch can, fuel pump rewire, booger shifter bushings, solid engine mounts, energy suspension bushings.

2014 Genesis Coupe 3.8 R-Spec
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post #4 of 49 (permalink) Old 12-04-2016, 08:17 PM
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Sure thing, keep us posted!!!

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FM Stock Appearing Stage 5 Buildup (E1 Turbo, Factory cams/gears) Turn Key Ready
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post #5 of 49 (permalink) Old 12-05-2016, 11:47 PM Thread Starter
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Well, I'm going to guess that it's because of this. It makes perfect sense based on the way the logs look. Installed a new one tonight, will button it up tomorrow and do some testing and report back.

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2005 ACR
Duster360 custom tune, 16G BWS, Fully bored TB, Meth Injection,1025cc injectors, over-sized valves,HKS BOV, AGP WGA, 3 bar map/tip, Thermal R&D 3" TBE, AEM CAI, AEM wideband, MPx catch can, fuel pump rewire, booger shifter bushings, solid engine mounts, energy suspension bushings.

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post #6 of 49 (permalink) Old 12-08-2016, 05:42 PM Thread Starter
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Well, no dice. Still knocks if I try to go over 21* timing so matter what I do. Doesn't seem to be as bad as it used to be, adding 6* timing results in a 3* STKR where as it used to be 2* would cause LTKR.

Anyone have any ideas at all?

2005 ACR
Duster360 custom tune, 16G BWS, Fully bored TB, Meth Injection,1025cc injectors, over-sized valves,HKS BOV, AGP WGA, 3 bar map/tip, Thermal R&D 3" TBE, AEM CAI, AEM wideband, MPx catch can, fuel pump rewire, booger shifter bushings, solid engine mounts, energy suspension bushings.

2014 Genesis Coupe 3.8 R-Spec
Has some mods
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post #7 of 49 (permalink) Old 12-09-2016, 07:44 AM
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post a data log..

how about the basics,
try new coil and Plugs - NGK 4306, lztr5a-13 -- gap .040
pull the injectors pressurize and fire off each one.. make sure there is a good mist..

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post #8 of 49 (permalink) Old 12-09-2016, 09:09 AM Thread Starter
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I suppose it would be helpful to provide some info for you, right?

Log file: https://dl.dropboxusercontent.com/u/...D216970_07.log

Here is what I've already tried

Only run cheveron 91 (or shell if I have to, never anything else)
NGK 1 step colder plugs, gapped 0.034 and 0.040
NGK 4306 gapped 0.034 and 0.040 (less than 500 miles on these plugs)
Boost leak tested
replaced the cracked manifold
exhaust leak checked
brand new valves, guides and seals
put the PCV on a vented catch can (was on a catch can with a check valve)
did several cleanings using mopar ccc
been running 50/50 meth for a few months now
coil was replaced less than 1 year ago
plug wires are less than 1 year old
added heat shielding where I could
injectors are less than a year old, but I'll give that test a try. I've been wondering how to test which cylinder(s) are knocking thinking maybe 1 or two of them are leaning out, but how could that be with meth?
replaced knock sensor

I know I've done more, just cant think of anything else.

2005 ACR
Duster360 custom tune, 16G BWS, Fully bored TB, Meth Injection,1025cc injectors, over-sized valves,HKS BOV, AGP WGA, 3 bar map/tip, Thermal R&D 3" TBE, AEM CAI, AEM wideband, MPx catch can, fuel pump rewire, booger shifter bushings, solid engine mounts, energy suspension bushings.

2014 Genesis Coupe 3.8 R-Spec
Has some mods
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post #9 of 49 (permalink) Old 12-09-2016, 09:31 AM
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Try a leakdown test....

go ahead...change yours too now; again
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post #10 of 49 (permalink) Old 12-09-2016, 09:36 AM Thread Starter
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Quote:
Originally Posted by lVlemphizStylez View Post
Try a leakdown test....
alright. I'll get back with the results later today

2005 ACR
Duster360 custom tune, 16G BWS, Fully bored TB, Meth Injection,1025cc injectors, over-sized valves,HKS BOV, AGP WGA, 3 bar map/tip, Thermal R&D 3" TBE, AEM CAI, AEM wideband, MPx catch can, fuel pump rewire, booger shifter bushings, solid engine mounts, energy suspension bushings.

2014 Genesis Coupe 3.8 R-Spec
Has some mods
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post #11 of 49 (permalink) Old 12-09-2016, 11:16 AM
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Like I said in the other post, dump some race gas in it, turn off the Meth and see what happens then.
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post #12 of 49 (permalink) Old 12-09-2016, 12:47 PM Thread Starter
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Originally Posted by HybridKid View Post
Like I said in the other post, dump some race gas in it, turn off the Meth and see what happens then.
I've added octane booster before, it did help. That's why I've been trying to clean the pistons, run meth, etc. I was thinking it was crap on the pistons creating a hot spot.

Just about done with the leak down test, cylinders 1 and 2 look good, need to check 3 and 4.

2005 ACR
Duster360 custom tune, 16G BWS, Fully bored TB, Meth Injection,1025cc injectors, over-sized valves,HKS BOV, AGP WGA, 3 bar map/tip, Thermal R&D 3" TBE, AEM CAI, AEM wideband, MPx catch can, fuel pump rewire, booger shifter bushings, solid engine mounts, energy suspension bushings.

2014 Genesis Coupe 3.8 R-Spec
Has some mods
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post #13 of 49 (permalink) Old 12-09-2016, 01:12 PM
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Originally Posted by titan2782 View Post
I've added octane booster before, it did help. That's why I've been trying to clean the pistons, run meth, etc. I was thinking it was crap on the pistons creating a hot spot.

Just about done with the leak down test, cylinders 1 and 2 look good, need to check 3 and 4.
The meth probably has cleaned the pistons already, it doesn't take much for the steam created by the water to do that.
Bro, put the race gas in and try it. Quit being so stubborn.
Even Stage 3 cars didn't like octane booster in HOM mode and would jump out of it because of knock.
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post #14 of 49 (permalink) Old 12-09-2016, 01:44 PM Thread Starter
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Here are the results. The compression test was the same on all cylinders and I let it pump 5 times each. Click the image for a big version, but as you can see, leak down was acceptable.

as far as race gas, I'll have to find a place to get some. I don't like running octane booster. I thought the pistons were clean, too. If you look in the plug hole, they look good, but i stuck my borescope in there and there is still some garbage. I was assuming that was the issue, and I guess I have to assume that's the issue still.


2005 ACR
Duster360 custom tune, 16G BWS, Fully bored TB, Meth Injection,1025cc injectors, over-sized valves,HKS BOV, AGP WGA, 3 bar map/tip, Thermal R&D 3" TBE, AEM CAI, AEM wideband, MPx catch can, fuel pump rewire, booger shifter bushings, solid engine mounts, energy suspension bushings.

2014 Genesis Coupe 3.8 R-Spec
Has some mods
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post #15 of 49 (permalink) Old 12-09-2016, 01:59 PM
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Originally Posted by titan2782 View Post
If you look in the plug hole, they look good, but i stuck my borescope in there and there is still some garbage. I was assuming that was the issue, and I guess I have to assume that's the issue still.
No! The true tell is the spark plugs. Detonation shows up as shiny flecks or black/dark brown carbon flex on them. The shiny flecks are the worst ones as those are the aluminum from the pistons.
One man's garbage is another man's 'No Problem Man'. A bore scope is only usually used to check more catastrophic issues than you are worrying about. Combustion chambers are not the pretties things to begin with....................even on a perfect running engine.
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