[jlaudio11]

Originally Posted by JSH

1:1? For example, 30 lb of boost and 30° of advance?

I’m thinking more of the rule of thumb like nitrous. Best NA timing and pull a degree for every 50hp of nitrous or 1lb of boost in this case.

[18.2SS.1LE]

Originally Posted by jlaudio11

I’m thinking more of the rule of thumb like nitrous. Best NA timing and pull a degree for every 50hp of nitrous or 1lb of boost in this case.

Yep, this was 93 octane street stuff though. Would've had to re-evaluate our strategy for built engines on race gas/E85 running 30 psi.

[KingLT1]

Originally Posted by jlaudio11

I’m thinking more of the rule of thumb like nitrous. Best NA timing and pull a degree for every 50hp of nitrous or 1lb of boost in this case.

I agree with this to some degree especially when referencing pump gas, but it's still sort of a blanket statement. Coming from my NA LT1 that had 28 degrees of timing on E85, I now run 20 degrees @ 10 psi of boost with E60. Been this way since 2019 still going strong. On pump gas I would have had to pull 16 degrees of timing.

I have tuned other LT1 based 6th gens that were forged, 1 pt lower compression, and run 22-24 degrees of timing on 12-15psi of boost with E50-60 fuel...no issue with a 7-heat range plug

LT4 is 1.5 point lower in compression, and they are perfectly fine at stock timing (24 degrees) or slightly above on E60 with 16-18 psi making 3-400hp over stock.

Moral of the story, there are too many variables (compression, fuel, engine efficiency) to simply say pull X amount of timing per 1psi of boost. The best thing you can do when making a lot more power vs stock is to start with conservative timing, read the plugs, and creep up on timing until the timing mark on the ground strap is in an ideal range.

[ZL1_1LE]

Originally Posted by KingLT1

I agree with this to some degree especially when referencing pump gas, but it's still sort of a blanket statement. Coming from my NA LT1 that had 28 degrees of timing on E85, I now run 20 degrees @ 10 psi of boost with E60. Been this way since 2019 still going strong. On pump gas I would have had to pull 16 degrees of timing.

I have tuned other LT1 based 6th gens that were forged, 1 pt lower compression, and run 22-24 degrees of timing on 12-15psi of boost with E50-60 fuel...no issue with a 7-heat range plug

LT4 is 1.5 point lower in compression, and they are perfectly fine at stock timing (24 degrees) or slightly above on E60 with 16-18 psi making 3-400hp over stock.

Moral of the story, there are too many variables (compression, fuel, engine efficiency) to simply say pull X amount of timing per 1psi of boost. The best thing you can do when making a lot more power vs stock is to start with conservative timing, read the plugs, and creep up on timing until the timing mark on the ground strap is in an ideal range.

So if that is the "standard" way of doing it, why do others go with higher timing and refuse to change? Are they just chasing numbers on the dyno for the sake of bragging rights?

[KingLT1]

Originally Posted by ZL1_1LE

So if that is the "standard" way of doing it, why do others go with higher timing and refuse to change? Are they just chasing numbers on the dyno for the sake of bragging rights?

Yeah, that could be... Dyno numbers sell parts and promote business. Some shops will also put all the timing in it to make a number and pull it back out before giving it to the customer. Regardless I don't believe there are any standards anymore. I was just pointing out that those "rule of thumbs" don't always line up with every combination.

[ZL1_1LE]

Originally Posted by KingLT1

Yeah, that could be... Dyno numbers sell parts and promote business. Some shops will also put all the timing in it to make a number and pull it back out before giving it to the customer. Regardless I don't believe there are any standards anymore. I was just pointing out that those "rule of thumbs" don't always line up with every combination.

Man that is a crazy sad business model

[Joshinator99]

Originally Posted by KingLT1

Yeah, that could be... Dyno numbers sell parts and promote business. Some shops will also put all the timing in it to make a number and pull it back out before giving it to the customer. Regardless I don't believe there are any standards anymore. I was just pointing out that those "rule of thumbs" don't always line up with every combination.

Well said and spot on as always.

[Katech_Mike]

It's all about knowing when to say when based on experience and the specific combination of parts.

Just because it will take a certain number doesn't mean it wants it.

[jlaudio11]

Originally Posted by KingLT1

I agree with this to some degree especially when referencing pump gas, but it's still sort of a blanket statement. Coming from my NA LT1 that had 28 degrees of timing on E85, I now run 20 degrees @ 10 psi of boost with E60. Been this way since 2019 still going strong. On pump gas I would have had to pull 16 degrees of timing.

I have tuned other LT1 based 6th gens that were forged, 1 pt lower compression, and run 22-24 degrees of timing on 12-15psi of boost with E50-60 fuel...no issue with a 7-heat range plug

LT4 is 1.5 point lower in compression, and they are perfectly fine at stock timing (24 degrees) or slightly above on E60 with 16-18 psi making 3-400hp over stock.

Moral of the story, there are too many variables (compression, fuel, engine efficiency) to simply say pull X amount of timing per 1psi of boost. The best thing you can do when making a lot more power vs stock is to start with conservative timing, read the plugs, and creep up on timing until the timing mark on the ground strap is in an ideal range.

100% agree, my rule of thumb was more of a general starting point. Not a an end all be all on perfect timing for every setup.

[ZLRob]

Originally Posted by KingLT1

I agree with this to some degree especially when referencing pump gas, but it's still sort of a blanket statement. Coming from my NA LT1 that had 28 degrees of timing on E85, I now run 20 degrees @ 10 psi of boost with E60. Been this way since 2019 still going strong. On pump gas I would have had to pull 16 degrees of timing.

I have tuned other LT1 based 6th gens that were forged, 1 pt lower compression, and run 22-24 degrees of timing on 12-15psi of boost with E50-60 fuel...no issue with a 7-heat range plug

LT4 is 1.5 point lower in compression, and they are perfectly fine at stock timing (24 degrees) or slightly above on E60 with 16-18 psi making 3-400hp over stock.

Moral of the story, there are too many variables (compression, fuel, engine efficiency) to simply say pull X amount of timing per 1psi of boost. The best thing you can do when making a lot more power vs stock is to start with conservative timing, read the plugs, and creep up on timing until the timing mark on the ground strap is in an ideal range.

Super well said, there are way too many variables to say, "oh there's a rule of thumb and this amount of timing applies to boost, nitrous etc." Build always comes into factor. Compression ratio, plug heat ranges, fuel being used and more to be able to say for certain how much timing your engine is capable of running. The only way to know for sure is to have a well educated/ seasoned tuner familiar with whatever platform you are working on who is more concerned about power production rather than chasing inflated numbers on the Dyno. That's why I prefer a street tune before a Dyno tune (but that has certain advantages not achievable on most public roads as well).

[Megahurtz]

LT4's will actually respond to more timing above 6000 RPM. Look at how the Blackwings are tuned from the factory.

But King LT1 and Katech_Mike have already shared definitive facts. Essentially it all depends. lol

[ZLRob]

Originally Posted by Megahurtz

LT4's will actually respond to more timing above 6000 RPM. Look at how the Blackwings are tuned from the factory.

But King LT1 and Katech_Mike have already shared definitive facts. Essentially it all depends. lol

This statement is very true. I've found the same as well without even knowing about the Blackwings.

[JSH]

I discussed the spark advance topic with a nationally known LT4 tuner last week and was surprised to find out that he uses 22° of advance, which is what my current tuner is aiming for, I believe. On the other hand, numerous tuners have informed me that they use 23 to 24°. Perhaps it depends on the specific build.

[Katech_Mike]

Originally Posted by JSH

I discussed the spark advance topic with a nationally known LT4 tuner last week and was surprised to find out that he uses 22° of advance, which is what my current tuner is aiming for, I believe. On the other hand, numerous tuners have informed me that they use 23 to 24°. Perhaps it depends on the specific build.

There's no set number for ignition timing. There are MANY factors that influence how much timing a specific combo wants. There may be a general range that you'll think it may end up at based on prior experience but to just say that something will want or take xx degrees of timing before actually running it is ignorant.