Pull Timing At What CR
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Pull Timing At What CR I'm just beginning to explore the world of aftermarket heads, so please forgive my naivety. I've been trying to find out at what CR you have to start pulling timing? Specifically, the 10.5 CR LS6 heads. Can you run 28 or 29 degrees of timing at that CR?
Last edited by Predator; Dec 23, 2005 at 10:02 AM.
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Thanks Viper, I see, there's no general rule-of-thumb that cars with CRs of 11:1, for example, or 11.5:1, or whatever usually need to have timing pulled? I was thinking that 10.5 is pretty close to stock and you could run with full timing. The truth is that I want to get a set of LS6 heads but I don't want to mess with my timing curve.
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93 Octane. If you're running full timing with 11:1 and 93 octane, I think you just answered my question: full timing is feasible with 10.5:1. Great news to me, and I appreciate your help!
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You can run 27-28 degrees of advance at 11 to 1 compression... I am and several here on the forum are doing it with even higher static compression. Don't worry so much about static and concentrate on your DCR. Many threads here on the subject, basically shoot for a DCR of 8.4 - 8.5 on 93 octane gas...
If you are worried about the LS6 heads, don't be. What cam, head-gasket are you running???
If you are worried about the LS6 heads, don't be. What cam, head-gasket are you running???
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Originally Posted by SideStep
You can run 27-28 degrees of advance at 11 to 1 compression... I am and several here on the forum are doing it with even higher static compression. Don't worry so much about static and concentrate on your DCR. Many threads here on the subject, basically shoot for a DCR of 8.4 - 8.5 on 93 octane gas...
If you are worried about the LS6 heads, don't be. What cam, head-gasket are you running???
If you are worried about the LS6 heads, don't be. What cam, head-gasket are you running???
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Originally Posted by Predator
Thanks SS, cam in sig, stock heads at the moment, but big plans for the spring.
Good Luck,
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Originally Posted by Predator
Does that contradict what's been said??
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Originally Posted by DramaFoYoMama
Is that an actual question, or are you just attempting to be a smartass? Everyone is telling you to run 27-28*, but what's the point on LS6 heads? Even if it doesn't knock, I seriously doubt it will make any extra power.
Read this:
https://ls1tech.com/forums/advanced-engineering-tech/254868-ignition-timing-101-a.html
Very good information in the 1st page. Keep in mind that every car is going to be different, no one can really say for sure "you can run a 29 deg of timing and be ok for sure". Especially with a head with a welded CC, diffences in the CC are going to make a differnece in the combustion process. I would wait to do the heads until you can retune. Or just go ahead and slap it together and hope for the best.
https://ls1tech.com/forums/advanced-engineering-tech/254868-ignition-timing-101-a.html
Very good information in the 1st page. Keep in mind that every car is going to be different, no one can really say for sure "you can run a 29 deg of timing and be ok for sure". Especially with a head with a welded CC, diffences in the CC are going to make a differnece in the combustion process. I would wait to do the heads until you can retune. Or just go ahead and slap it together and hope for the best.
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I apologize if I came off as being rude. I saw the extra question mark and thought that maybe you thought I didn't know what I was talking about. Basically, the more efficient a head is, the less spark advance it needs to make power. Like already stated, I wouldn't put LS6 heads on an F-body with an LS1 tune as it's asking for trouble IMO. It will knock like crazy and possibly ruin the motor if it goes lean. Lean and extra spark = 
Just remember that more isn't always better. 
Just remember that more isn't always better. Thread Starter
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Appreciate the link, that'll keep me busy for awhile.
I can retune at any time, I was just hoping I wouldn't have to mess with my timing table, just fueling changes. Truth is I haven't figured out the best way to tune my timing table. Sounds like I have to learn, or wait on heads until I know what I'm doing with timing. The only changes to my timing table are for idle, and I hired a tuner to do that. I'm comfortable doing fueling changes, and I have an LM-1 to assist me. That's why I was wondering (hoping) that I could do heads and just worry about fueling, but maybe I'm in over my head. I know the Patriot 243 heads I mentioned would probably have a compression ratio of 10.5:1, hence my original question (post). I'm trying to learn more about cylinder heads and tuning for them, but I have a long way to go. Thanks.
I can retune at any time, I was just hoping I wouldn't have to mess with my timing table, just fueling changes. Truth is I haven't figured out the best way to tune my timing table. Sounds like I have to learn, or wait on heads until I know what I'm doing with timing. The only changes to my timing table are for idle, and I hired a tuner to do that. I'm comfortable doing fueling changes, and I have an LM-1 to assist me. That's why I was wondering (hoping) that I could do heads and just worry about fueling, but maybe I'm in over my head. I know the Patriot 243 heads I mentioned would probably have a compression ratio of 10.5:1, hence my original question (post). I'm trying to learn more about cylinder heads and tuning for them, but I have a long way to go. Thanks.
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Why don't you copy and paste the timing table from a Z06 as they have the 243 heads? It will give you a place to start at. You can add in the idle timing that you did to the table. There is more than one recommendation around here on how to tune the timing table. I would say tune it to how you like to drive the car. 
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Originally Posted by DramaFoYoMama
I apologize if I came off as being rude. I saw the extra question mark and thought that maybe you thought I didn't know what I was talking about. Basically, the more efficient a head is, the less spark advance it needs to make power. Like already stated, I wouldn't put LS6 heads on an F-body with an LS1 tune as it's asking for trouble IMO. It will knock like crazy and possibly ruin the motor if it goes lean. Lean and extra spark = Just remember that more isn't always better.
Just remember that more isn't always better. Thread Starter
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Originally Posted by DramaFoYoMama
Why don't you copy and paste the timing table from a Z06 as they have the 243 heads? It will give you a place to start at. You can add in the idle timing that you did to the table. There is more than one recommendation around here on how to tune the timing table. I would say tune it to how you like to drive the car.
I think you get my point that I was hoping I could slap on a set of heads and just tune fueling (because of my lack of knowledge). Sorry about the misunderstanding, but I never thought you didn't know what you were talking about, I'm the one who's challenged here.
Thanks.