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1,196 Posts
2 years ago I switched my heavily reworked cast iron heads for a pair of really good Brodix aluminum ones. I had run the previous cast iron heads for 7 years of so on my blower motor and I had what I thought a good tune and was getting about 14-15 mpg along with alot of performance.
Once I switched to the aluminum heads I couldn't seem to nail down the tune and went through last summer without finding what I thought was a good tunup.
This winter I went to a 540 short block and added my aluminum heads and blower assembly. Again I work on the tuning of the motor and couldn't get a good looking plug.
I read lots on the wide band oxygen sensors and guys like MotorHead told me to get the LM-1. A portable unit I could use to tune other cars as well.
In Canada it runs about $500 with tax but was it ever worth it??
It quickly showed me to be way too rich with readings in the mid 12.5 and as low as 10 under power.
Following the forum related to the LM-1 I learned how to use the LM-1 wide band, the ranges I was looking for and preceeded to try and get the readings they recommended.
I found the idle circuit is used to for cruising at 60 or 70 miles per hour and I really needed to push the rpm in the 3000 range to get onto the main jets.
I learned that the idle screws can be as sensitive as 1/8th of a turn going from rich to lean.
That I had to jet down 10 TEN sizes to get in the magical 13.8 cruising range and even dropped the secondary jetts 6 sizes to get into the 12 range under load.
While this tool is expensive it is a great way to quickly find out what you car's carb is doing.
I am a little concerned with the readings and it is steady around 13.8-.9 and the car has never run better but I am going to also install temperature probes in the exhaust. At least 2 probes and bought a meter to record this also.
The problem is my headers are installed and wrapped and I need to remove them to install the stainless bosses I want, 2 per header to checking temperature.
So along with the temperture probes and the wide band oxygen sensors I hope to finally zero in on the perfect idle mixture, main jets for cruisng mpg and a same but leaner top end.
I then intend to tune up my sons's car and some of my friends cars to optimum jetting and the fun of getting a car to run better then ever.
At my horsepower level a seat of the pants is no way to tune it.
100 horse here or there is not going to show up by how it feels.
I am not asking advice just sharing what I feel is a worthwhile tool for anyone truely wanting to dial in their car.
http://www.innovatemotorsports.com/products/lm1.php
This is some good reading on setting up the carbed engine with a wide band oxygen sensor. The narrow band is garbage and is nothing more then a rich lean switch. You need the wide band to really do any tuning.
I followed this.
http://www.innovatemotorsports.com/resources/Stan1.php
Once I switched to the aluminum heads I couldn't seem to nail down the tune and went through last summer without finding what I thought was a good tunup.
This winter I went to a 540 short block and added my aluminum heads and blower assembly. Again I work on the tuning of the motor and couldn't get a good looking plug.
I read lots on the wide band oxygen sensors and guys like MotorHead told me to get the LM-1. A portable unit I could use to tune other cars as well.
In Canada it runs about $500 with tax but was it ever worth it??
It quickly showed me to be way too rich with readings in the mid 12.5 and as low as 10 under power.
Following the forum related to the LM-1 I learned how to use the LM-1 wide band, the ranges I was looking for and preceeded to try and get the readings they recommended.
I found the idle circuit is used to for cruising at 60 or 70 miles per hour and I really needed to push the rpm in the 3000 range to get onto the main jets.
I learned that the idle screws can be as sensitive as 1/8th of a turn going from rich to lean.
That I had to jet down 10 TEN sizes to get in the magical 13.8 cruising range and even dropped the secondary jetts 6 sizes to get into the 12 range under load.
While this tool is expensive it is a great way to quickly find out what you car's carb is doing.
I am a little concerned with the readings and it is steady around 13.8-.9 and the car has never run better but I am going to also install temperature probes in the exhaust. At least 2 probes and bought a meter to record this also.
The problem is my headers are installed and wrapped and I need to remove them to install the stainless bosses I want, 2 per header to checking temperature.
So along with the temperture probes and the wide band oxygen sensors I hope to finally zero in on the perfect idle mixture, main jets for cruisng mpg and a same but leaner top end.
I then intend to tune up my sons's car and some of my friends cars to optimum jetting and the fun of getting a car to run better then ever.
At my horsepower level a seat of the pants is no way to tune it.
100 horse here or there is not going to show up by how it feels.
I am not asking advice just sharing what I feel is a worthwhile tool for anyone truely wanting to dial in their car.
http://www.innovatemotorsports.com/products/lm1.php
This is some good reading on setting up the carbed engine with a wide band oxygen sensor. The narrow band is garbage and is nothing more then a rich lean switch. You need the wide band to really do any tuning.
I followed this.
http://www.innovatemotorsports.com/resources/Stan1.php