Little help with $32 305 to 350
Little help with $32 305 to 350
Here is my car:
1988 Trans Am - originally 305 5-speed
Now - 350 truck motor from a late 90s truck, probably TBI. LS1 injectors, AFPR (not exactly sure where it is set at), 180 degree t-stat.
Current tune - AKFU bin with injector constant changed to 24, fans turned down to 190 and off at 185. Fuel Pressure is unknown, but I will be setting it to about 43 psi before I really start tuning.
At idle the BLMs show it is running rich, like 111-122s. The Integrator was 128 up to 160. I am going to turn my FP down and see if that helps things, but I don't want to spend forever blind and I seem to have lost my FP gauge.
So, finally, the question. I have read and read the $32B tuning article by funstick, but for some reason it just isn't sticking. Would the best bet to get the fuel pressure right, then copy the BPW Fuel vs. Load table, Spark Advance Table, PE vs Temp, and what other tables over, then go from there? I have a bin from a 2.77 350 f-body from 88 that I am using to compare. My AKFU bin was the one I pulled off my stock chip as I couldn't find an updated version.
Thanks!
Douglas
1988 Trans Am - originally 305 5-speed
Now - 350 truck motor from a late 90s truck, probably TBI. LS1 injectors, AFPR (not exactly sure where it is set at), 180 degree t-stat.
Current tune - AKFU bin with injector constant changed to 24, fans turned down to 190 and off at 185. Fuel Pressure is unknown, but I will be setting it to about 43 psi before I really start tuning.
At idle the BLMs show it is running rich, like 111-122s. The Integrator was 128 up to 160. I am going to turn my FP down and see if that helps things, but I don't want to spend forever blind and I seem to have lost my FP gauge.
So, finally, the question. I have read and read the $32B tuning article by funstick, but for some reason it just isn't sticking. Would the best bet to get the fuel pressure right, then copy the BPW Fuel vs. Load table, Spark Advance Table, PE vs Temp, and what other tables over, then go from there? I have a bin from a 2.77 350 f-body from 88 that I am using to compare. My AKFU bin was the one I pulled off my stock chip as I couldn't find an updated version.
Thanks!
Douglas
Supreme Member
Joined: Jan 2002
Posts: 1,162
Likes: 1
From: California
Car: Z28
Engine: L98
Transmission: T56
In my opinion..
1) set the AFPR to stock fuel pressure. Or ditch it and get a stock regulator. once you tune your own BIN, there isn't much reason (in my opinion when using a TPI setup) to mess with fuel pressure.
2) bump up your injector constant a bit. I know the LS1 injectors are rated at a higher fuel pressure because of the LS1 system, but they still should be a bit bigger than 24# at TPI pressure. The smaller LS1 injectors are approx 24.7#, and the larger ones are in the neighborhood or 26-27#. Check out this post for some excellent info:
https://www.thirdgen.org/forums/2016428-post30.html
Once you bump up your injector constant a bit, the ECM will cut down your injector pulsewidths and your BLM's will come more in line. Then you can tune from there. You don't want to lower fuel pressure to cover up an incorrect injector constant.
1) set the AFPR to stock fuel pressure. Or ditch it and get a stock regulator. once you tune your own BIN, there isn't much reason (in my opinion when using a TPI setup) to mess with fuel pressure.
2) bump up your injector constant a bit. I know the LS1 injectors are rated at a higher fuel pressure because of the LS1 system, but they still should be a bit bigger than 24# at TPI pressure. The smaller LS1 injectors are approx 24.7#, and the larger ones are in the neighborhood or 26-27#. Check out this post for some excellent info:
https://www.thirdgen.org/forums/2016428-post30.html
Once you bump up your injector constant a bit, the ECM will cut down your injector pulsewidths and your BLM's will come more in line. Then you can tune from there. You don't want to lower fuel pressure to cover up an incorrect injector constant.
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