Carb tuning with t56???
10-05-2014, 01:27 PM
#1
Staging Lane
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Carb tuning with t56??? Ok guys new update!! I got my t56 in yesterday and completed the 75 mile drive back home with no real issues which is great love the new feel of the car vast improvement from the 700r4, so thanks to everyone for talking me into it!!
Now what I'm curious about is are there any tips or techniques for tuning the carb and timing that vary from an auto outside of setting idle mixture??
It may be due to the cam and wide 3.23s out back but it doesn't have the bottom end it used to but once it's up in the primaries runs out really strong but a hair lean.. So I'll be playing with it as I go, as of now it's all still set from where I had it as an auto car..
Any input is welcome, but I can gladly say this car finally feels like a real muscle car now!! And gears will be in the works over the next year along with a 12 bolt!!
Now what I'm curious about is are there any tips or techniques for tuning the carb and timing that vary from an auto outside of setting idle mixture??
It may be due to the cam and wide 3.23s out back but it doesn't have the bottom end it used to but once it's up in the primaries runs out really strong but a hair lean.. So I'll be playing with it as I go, as of now it's all still set from where I had it as an auto car..
Any input is welcome, but I can gladly say this car finally feels like a real muscle car now!! And gears will be in the works over the next year along with a 12 bolt!!
10-05-2014, 04:20 PM
#2
Very cool to hear about your t-56 conversion. I have been considering this myself.
In regards to the low end power, unlike an automatic where a the torque converter can help multiply the torque down low, a manual transmission must do this with gear. For me, a 3.23 rear gear would be a no go. I would want a 4.10
For the timing, tailoring a curve is important with a stick shift. With a stick shift you will often load the engine at a very low RPM which might not happen with an auto. At low RPM under a load you need to reduce the timing to avoid detonation. Another thing that you will want to do is work on your MAP curve. If you don't have a MAP sensor in your system, it is very desirable with a stick car. So, your timing might look something like 12 degrees at idle that gradually increases to 30 at 3000 RPM with 12 degree range in your MAP advance. Then just play with it from there until it feels best.
As for the carburetor, tuning it will be roughly the same except the idle might be set lower, but if it is a mechanical secondary carburetor the driving technique is just a bit more conservative at lower RPM.
In regards to the low end power, unlike an automatic where a the torque converter can help multiply the torque down low, a manual transmission must do this with gear. For me, a 3.23 rear gear would be a no go. I would want a 4.10
For the timing, tailoring a curve is important with a stick shift. With a stick shift you will often load the engine at a very low RPM which might not happen with an auto. At low RPM under a load you need to reduce the timing to avoid detonation. Another thing that you will want to do is work on your MAP curve. If you don't have a MAP sensor in your system, it is very desirable with a stick car. So, your timing might look something like 12 degrees at idle that gradually increases to 30 at 3000 RPM with 12 degree range in your MAP advance. Then just play with it from there until it feels best.
As for the carburetor, tuning it will be roughly the same except the idle might be set lower, but if it is a mechanical secondary carburetor the driving technique is just a bit more conservative at lower RPM.
10-05-2014, 05:35 PM
#3
Staging Lane
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Awesome!! Ya I have a 4.10 posi 12 bolt already just have to decide how I want to go about holding it in place.... Either torque arm or other options... That a for sure thing just have to have time and money to get it done...
I kind of figured the carb would be similar.. Any tips on power valve setting?? I used the half vacuum at idle way before.. It's doing exactly what you said with high load at low rpm so I'd like to work that out.. I'll play with the timing a bit, and I do have a map but I just haven't wrapped my head around how to set the table and how it actually adds the timing in, plus it's a weird conversion that I can't seem to wrap my head around in order to set it up.. Any advise there? Or know of any specific articles/posts I can read to help? I've searched but keep getting it all turned around in my head...
I kind of figured the carb would be similar.. Any tips on power valve setting?? I used the half vacuum at idle way before.. It's doing exactly what you said with high load at low rpm so I'd like to work that out.. I'll play with the timing a bit, and I do have a map but I just haven't wrapped my head around how to set the table and how it actually adds the timing in, plus it's a weird conversion that I can't seem to wrap my head around in order to set it up.. Any advise there? Or know of any specific articles/posts I can read to help? I've searched but keep getting it all turned around in my head...
10-05-2014, 05:39 PM
#4
Most of this is talking about automatic cars, but there is some good stuff in there.
https://ls1tech.com/forums/carburete...dtigger-p.html
As for getting used to the scaling. I just drove around while watching it. LOL There are laws in Florida against texting and driving, but they did not say anything about MAP tuning and driving.
https://ls1tech.com/forums/carburete...dtigger-p.html
As for getting used to the scaling. I just drove around while watching it. LOL There are laws in Florida against texting and driving, but they did not say anything about MAP tuning and driving.