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Formerly LSNotch
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Discussion Starter #1
Hi,
I thought I share this information I came across regarding the TFS 11R heads and their chamber efficiency. I know a lot of folks always think that you need a ton of timing to make power. This may be due to old school mentality and also because it applies to most inline heads but not necessarily true with the 11Rs. I've worked with LS engines and they do make a ton of power with VERY little timing due to their efficient chamber, most run 22-26* at peak or total timing.

So here's an excerpt from an online pdf where they have a lot of head manufacturers talking about their cylinder head strategies, etc. This one specifically is from Trick Flow. https://www.eliminatorproducts.com/uploads/assets/h_testimonials/N25GSG90MkVsUEE0ZVc1S1ZvSnNVTllTVUV4b2dDd0tWSXNqUExYY2JKUlkrd1QzcXpiSlJXWmZMZFlkOG9OVWxqMmM5aXFPMUFOZ3RmSHdCOGpSeVB0QVZranZiWEw2QUh2ZUZ0bm9wd0VPTjJPM2MxQ0xWQ1VRdjJ2czFKL2w=.pdf

"CHAMBER EFFICIENCY Yet another advantage of flattening out the valve angle is an overall improvement in combustion chamber efficiency. Pointing the valves away from the cylinder wall and closer to the center of the bore not only frees up space for larger valves, it also decreases chamber shrouding, burn time, and the potential for detonation. By nature, ignition advance increases pumping losses, as the pistons must fight against an expanding air/fuel mixture that’s ignited before TDC on the compression stroke. Since an efficient combustion chamber needs less ignition timing advance, the resulting decrease in pumping losses increases horsepower . “When designing our 11R cylinder head, we basically took a 15-degree Twisted Wedge casting and flattened the valve angle to 11 degrees,” says Cory Roth of Trick Flow Specialties. “This gave us a much more efficient combustion chamber that only needs 26-28 degrees of ignition advance. That’s as good as any LS head out there.”
 

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On my car 32deg was the sweet spot But I only tried 30 32 and 33.5 so I guess next go round I may try 28 just to see what happens.
 

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Formerly LSNotch
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820 Posts
Discussion Starter #3
It’s all about the most average power and not only peak.
 

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When I had mine on the dyno I found 27 degrees to be the sweet spot but I am also boosted. I tried a little more timing but the gains were very small. For an NA car, the timing should be more advanced. My street tune I pull 2 degrees for safety but I can confirm my cars timing runs right there.
 

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Formerly LSNotch
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Discussion Starter #5
Right now mine is set at 28* total. Once I am able to do more testing I’m going tp try 29* to see if it makes a difference.
 

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Formerly LSNotch
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820 Posts
Discussion Starter #7
28-32, after 32 power drops like a rock
Thanks Woody. I actually followed your advice and why I started with 28*, but I'm going to try 1-2* to see what it does. Do compression affect this numbers? I have about 11.3-11.4 based on online calculator but a hefty cam that may help to "bleed" some of it off, and why I decided to start on the low side.
 

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It didnt matter the static compression, cubic inch, induction, etc.. On naturally aspirated engines with an 11R head on a super flow 901, I tried every timing number a few dozen times, every single time over 32, power fell through the floor.
 

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I have same experience as Woody. Over 32° and MPH drops off (no dyno numbers but MPH is an indication of horsepower). AFR's nonetheless. I usually leave it backed down to 29 or 30 "just in case"-and don't generally see any MPH drop until mid 20's, and ET drops off too.

"everyone" said with methanol (100%) I'd have to bump the timing to 40. Wrong. Exactly the same as gas. For some reason it also "likes" the same plugs as it does on gas.
 
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