LS swap 1999 c3500 single cab lb

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Christian Steffen

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I made a dumb mistake and missed the last few rows of the timing table when adjusting. It commanded 20* at 11lbs on pump gas. So it pulled 3-4 degrees of knock retard on the log. That ones on me haha

3-4 doesn't seem like all the much? Not what i'd like to see but I would think the knock sensors would have protected it. That said, 20* on 11 psi sounds like a lot lol I'm in the low teens depending on rpm at half that boost lol
 

CarolinaOBS

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3-4 doesn't seem like all the much? Not what i'd like to see but I would think the knock sensors would have protected it. That said, 20* on 11 psi sounds like a lot lol I'm in the low teens depending on rpm at half that boost lol
You’re right it is allot. It was way too much I forgot to change last few rows of the timing table from the NA tune I based it off of. I would have wanted it to command 14 to 15 degrees being on pump gas . Just wasn’t paying attention. Wish the knock sensors would have saved it at 6400 rpm computer probably just didn’t have enough time. My intercooler setup is pretty efficient so I’m the cool weather it allows me to get away with more abuse being charge temps rarely go up to 150
 

RDF1

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Are you running open loop or closed loop?
We have had a lot of issues with the MAF right at a Bend like yours is. Ended up just going Open loop SD and never looked back.

I always start out at 24* at 105kpa, 18* 135kpa, 14* 165kpa, 10* 200kpa for 93 octane.
It works good for 4.8, 5.3 and 6.0s so far. Then creep up from there.
But don't get greedy on timing, let your boost make your power and it will last a long time.
 

Supercharged111

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Closed loop with MAF. I did OLSD years ago and AFRs changed with the weather. It also didn't deal with elevation changes at all. This truck is around 24 degrees at 110kpa which seems to be about the knock threshold.
 

CarolinaOBS

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Are you running open loop or closed loop?
We have had a lot of issues with the MAF right at a Bend like yours is. Ended up just going Open loop SD and never looked back.

I always start out at 24* at 105kpa, 18* 135kpa, 14* 165kpa, 10* 200kpa for 93 octane.
It works good for 4.8, 5.3 and 6.0s so far. Then creep up from there.
But don't get greedy on timing, let your boost make your power and it will last a long time.
Only reason my maf is there is for the IAT sensor, otherwise it’s worthless as I’m running speed density. I had issues with it using maf right at the 90 when it was Na too.

thanks for the advice! The new short block has less compression also so it will be more friendly with the pump gas. The gas here sucks 93 you never really know what you’re gonna get.
 
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