411 Swap 383 Vortec Newbie To Tuning. Where To Start?

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Awest623

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I made some changed and did the following one change at a time.
Pasted an untouched L31 VE Table, truck did not run very good this way.
So I put it back to the way it was when I changed the cyl volume to 383, when the program changes it for you. Truck ran good again.
Basically in small increments, doubled the BRAF to get the truck to start without throttle input. RPM was hanging a little.
Backed some idle spark advance off from 400 to 1200 rpm. Truck seems to like it so far.

There is still so much that needs messed with, but it is now running better than ever. Still trying to learn.

Follow this guide for tuning your idle. There's a lot of steps and it'll take a while, but it'll give you a great running engine. Once you finish that, go through and tune your VE table, MAF, and then spark. I recommend you invest in a wideband sensor with a serial output otherwise you won't be able to tune the open loop portions of your tables, AEM makes some great ones. Once that's done you'll probably need to redo the idle tune, or maybe not.

It'll take a while to learn the ins and outs of tuning. @L31MaxExpress is a pro at it, I can also help you along the way. Also the HPTuners forum is a great resource.

If you'd like I can send you my scanner config that has all the histograms and data points you need to do just about any changes.
 

supspt454

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Follow this guide for tuning your idle. There's a lot of steps and it'll take a while, but it'll give you a great running engine. Once you finish that, go through and tune your VE table, MAF, and then spark. I recommend you invest in a wideband sensor with a serial output otherwise you won't be able to tune the open loop portions of your tables, AEM makes some great ones. Once that's done you'll probably need to redo the idle tune, or maybe not.

It'll take a while to learn the ins and outs of tuning. @L31MaxExpress is a pro at it, I can also help you along the way. Also the HPTuners forum is a great resource.

If you'd like I can send you my scanner config that has all the histograms and data points you need to do just about any changes.
Awesome. Thank you for the response. I will definatly check that out. A quick read over and checking my cam overlap, it seems to have 40* positive, so looks like ill be using this portion of his directions correct?

Cams over 15º overlap, idle 950-1100 all cells across the board, add 3-4 g/sec to idle airflow across the board both in P/N and in gear (HPT > Engine > Idle > Idle Airflow > Base Running Airflow), add 6º of idle timing 1200 rpm and under and 0.08 – 0.28 g/cyl inclusive (HPT > Engine > Spark Control > Spark Advance > Idle Spark Advance (in Park).
 

L31MaxExpress

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Awesome. Thank you for the response. I will definatly check that out. A quick read over and checking my cam overlap, it seems to have 40* positive, so looks like ill be using this portion of his directions correct?

Cams over 15º overlap, idle 950-1100 all cells across the board, add 3-4 g/sec to idle airflow across the board both in P/N and in gear (HPT > Engine > Idle > Idle Airflow > Base Running Airflow), add 6º of idle timing 1200 rpm and under and 0.08 – 0.28 g/cyl inclusive (HPT > Engine > Spark Control > Spark Advance > Idle Spark Advance (in Park).
What cam? Where is your current gm/cyl at idle. My 383 is higher than 0.28 at idle. Changes under 0.28 thus would do nothing for it.
 

supspt454

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What cam? Where is your current gm/cyl at idle. My 383 is higher than 0.28 at idle. Changes under 0.28 thus would do nothing for it.
Hi. All engine specs are in my sig. Here is the cam card. Also running 1.6 ratio rockers.
 

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L31MaxExpress

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Hi. All engine specs are in my sig. Here is the cam card. Also running 1.6 ratio rockers.
That tuning guide must be showing overlap at 0.050 and that cam is nowhere near that. That cam will idle tame as can be at 650 rpm with the stock idle timing advance. Maybe add 2* to stock at most. 383 will need more idle air because it is larger and more cam. I agree probably atleast 2-3 gms/sec more BRAF at hot idle. Personally, I multiplied the BRAF table by 1.2 to get started.
 

supspt454

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That tuning guide must be showing overlap at 0.050 and that cam is nowhere near that. That cam will idle tame as can be at 650 rpm with the stock idle timing advance. Maybe add 2* to stock at most. 383 will need more idle air because it is larger and more cam. I agree probably atleast 2-3 gms/sec more BRAF at hot idle. Personally, I multiplied the BRAF table by 1.2 to get started.
What about the VE table previously mentioned about copying from stock tune. When I did that it didn’t run good.
 

L31MaxExpress

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What about the VE table previously mentioned about copying from stock tune. When I did that it didn’t run good.
I find that surprising, but likely means your VE table is out of whack and the lower values it self changes to are leaning it out. My VE table ended up pivoting around the ~2,000 rpm axis very noticeably. Under 2,000 rpm wanted much lower numbers, over 2,000 rpm wanted much higher numbers.
 

supspt454

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That tuning guide must be showing overlap at 0.050 and that cam is nowhere near that. That cam will idle tame as can be at 650 rpm with the stock idle timing advance. Maybe add 2* to stock at most. 383 will need more idle air because it is larger and more cam. I agree probably atleast 2-3 gms/sec more BRAF at hot idle. Personally, I multiplied the BRAF table by 1.2 to get started.
Is that 2* across the board or 1200 and below
 
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