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Discussion Starter #1 (Edited)
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
 

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:agree: This tool is invalueable. I have had one for a year now and the car runs so much better. When Itook it to the dyno this fall and ran under their wideband and the results were almost perfect. I was off 2 jet sizes in the rear. Everything else was spot on. You really have no idea where your car is running until you get a wideband in there to see what it was doing. My idle is in the 13.7 range cruise is at 13.5 and WOT is right around 12.
 

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:agree: Norval It is a tool no tuner should be without. I opted for the Fast 170502 Dual Sensor wide band air/fuel meter, only because I could get the extra O2 sensor for an equivalent cost. It also can average the two O2 sensors to give an added perspective. I use it with my EFI tuning and consider it invaluable. I want to hook it up to the 70 LT-1 (carb) sometime soon, but just haven't got a "round to it":laughing:

Bullshark
 

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Discussion Starter #4
My next project is going to be trying to find the right range of spark plugs. I want to try different heat ranges and get the coldest plug that still remains clean and gives a good reading. I will try 3 different heat ranges and pick the one that gives the best looking reading.
The wide band and temperature sensors set up the fuel ratios but I want to find the right plug temperature.
I knwo a plug wants to run in the 500-800 Centigrade range and the difference between one set in a heat range is 75-125Centigrade.
I want a plug that works in the lower part of this range and yet never fouls.
I often run different heat ranges throughout the motor , the lean cylinders a colder plug and the richer cylinders a hotter plug.
I pull plug checks every now and then after a hard run across country, I have a really nice block and if a plug is a little richer or leaner then the others I will add of subtract a heat range for that cylinder.
 

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Discussion Starter #5
I liked the LM-1 because of the calibration feature. As the sensor wears with age you can calibrate or check the existing calibration to guarantee accuracy.
Every now and then I take an oxygen reading of normal air and it should show 20.9 If not I run a calibration and it resets to free air so I know it is accurate.
When you get a dyno tune the major part of that tune is the wide band oxygen sensor and setting up the carb right. I can do that all my myself as well as play with timing. I have an onboard timing control and often play with different settings but agian that is seat of the pants only
 

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My car runs perfect and the plugs always look good.

I can't really justify the cost for how I would marginally benefit.

Although my dad sure needs it :laughing: When he tunes his carbs they run worse and worse. I keep telling him needs to get it. His car backfire and all kinds of stuff and still won't believe me that the wide band will work :crazy:
 

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OK, I can't unnersand why a wide band is needed, the narrow band will say it's rich or lean....and go from there....so it rich...reduce jet/redo idle...
so it's lean....drill off idle transfer circit....

seems it should be still in the same range for proper operation cruising....

:crazy:
 

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Discussion Starter #8
OK, I can't unnersand why a wide band is needed, the narrow band will say it's rich or lean....and go from there....so it rich...reduce jet/redo idle...
so it's lean....drill off idle transfer circit....

seems it should be still in the same range for proper operation cruising....

:crazy:
Gene I have a narrow band in the car permanently and it is not worth the trouble. It is just a switch that switches on either side of 14.7
So it says it is rich? How rich? Define rich?? Lets say it is 13.8 a great mixture for general cruising and yet that is rich by the definition of rich of lean compared to 14.7
I know exactly how rich 13.8 or .9 is.
I also know that I want to have about 13-13.2 under load. That is rich for the narrow band and yet for hard running it is not even considered safe.
12.8 would be safe, 10 would even be acceptable for a blower or turbo.
NO Gene the narrow band won't do it. It is just a decoration on the dash.
I hated to spend the $500 but it was well worth it to arrive where I am now.
 

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Discussion Starter #9
My car runs perfect and the plugs always look good.

:
What is perfect? HOw do you know it is perfect?
I ran with 80's in the primaries for years, remember I have 2 850 double pumpers and 80's left me with good looking white plugs and yes I like them white. I thought I had a great running motor, tried different timing and I can do that on the fly running down the road. I fine tuned the dial until I was happy with the tune.
Now I run 72's, little 72's in a 850 and I feel that is tooooooo lean and yet my readings come back at 13.8 -14
Perfect for a good cruising car and better mileage then my old 80's
If you told me to try 72's I would think you are crazy to run that lean, sure to burn something out but yet the wide band tells me it is OK.
No surge, runs great, plugs look good so now I am installing the temp sensors in the exhuast to really see if I can trust the wide band.
I want about 1300 for the exhuast gases and if I am around 1420 I will worry and richen the mixture.
You can also tell detonation if I hook one of the temp sensors into the head and one in the exhaust.
A climbing head temp and a falling exhuast temp tells me there is detonation.
With the temp gage I can hook a thermocouple anywhere I please to monitor whatever temp but for now I will monitor the exhaust on 2 cylinders choosen at random.
I believe that spending the $500 for me was well worth it.
I will charge $50 for installing it on other's cars and doing the jetting for them getting the readings into the acceptable range. Might earn some of it's cost back.:thumbsup:
 

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this is what i have on the pt cruiser and will be going on the vette when i put in the new motor. they are worth their weight in gold for tuning that is for sure.
 

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I will charge $50 for installing it on other's cars and doing the jetting for them getting the readings into the acceptable range. Might earn some of it's cost back.:thumbsup:

$50 to install the O2 bung, run a calibration, re-jet the carb and run another calibration at a minimum. That is very reasonable Norval. :thumbsup:

Bullshark
 

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If you're got a laptop and can use it the LC-1 does the same thing and is only $200, same company.
 

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this is what i have on the pt cruiser and will be going on the vette when i put in the new motor. they are worth their weight in gold for tuning that is for sure.

Just curious, but isn't the pt computer controlled or did you change it?
 

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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.
Norval, sometimes you crack me up! :rolling: Although I'm sure tuning a monster motor like yours does present a lot of challenges.

Thanks for the great post. This is something I've been considering doing for a couple years now. I've got a few questions though. Did you need to make any changes other than the jets and idle mixture screws? I've heard you frequently need to change idle air bleeds. Are you planning to use the LMA-3 Aux Box to track the exhaust temp?

I've been considering using the LC-1. Does anybody here have experience with using this? Is it easy to configure with your laptop?

By the way, I feel like I've died and gone to heaven here on DC! We've got knowledgeable people like Norval, TT, Lars, Gary, Zwede, Jim Shea, Big Bird and some more than I'm sure I'm forgetting posting here and not much of the drivel you need to wade through elsewhere. :thumbsup:
 

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Discussion Starter #17
A motor like mine is not easy to feel little changes. It is a 540 with a blower, great heads , healthy cam and if it can't put out 800 plus horse something is definitly wrong with it. So again seat of the pants is not easy to feel.
If you get on it too hard the street tires just go up in smoke.

No I will monitor exhuast temperature seperate. I have a really nice dual temperature meter that store peak temp, tracks two different chanels and I will just keep an eye on the temp under different conditions.

Any of the wide band oxygen sensor should work. I just went with the LM-1 because Motorhead suggested it. I would go for whatever you get a deal on.
There is a good website to help understand what you are seeing and how to deal with it. A web site dedicated to tuning with the wide band oxygen sensor.
The LM-1 has it's own tuners forum so you can get backup support.
 

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I've been considering using the LC-1. Does anybody here have experience with using this? Is it easy to configure with your laptop?
I have the LC-1. It's easy to use. The main difference between it and the LM-1 is that the LM-1 has a built-in display. The LC-1 needs either a laptop or a special gauge. The LC-1 is great to add wideband support to an aftermarket EFI system. For under $200 complete with sensor you can add WB.
 

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I have the LC-1. It's easy to use. The main difference between it and the LM-1 is that the LM-1 has a built-in display. The LC-1 needs either a laptop or a special gauge. The LC-1 is great to add wideband support to an aftermarket EFI system. For under $200 complete with sensor you can add WB.
I KNOW my Fluke 73? DVM I have had for years now, is right dead nutz on...so what is so bad about using THAT for readout, other than preserving the readings over time/something....

I had loooked at one for 200 bux, from the Mega Squirt dealer, before I was forced outta there by .commmmmm errors....freeking computer, allways something....

I do get curious about things like my 2 bbl work truck though....:crazy: :lookinup:
 

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Discussion Starter #20
Gene your digital voltmeter would read out the voltage but how do you transfer that into ratio's? If the motor is not running and I turn on the LM my reading is 20.9 the exact ratio of oxygen in air. This is the calibration media. After that it shows ratios like 13-1 which is air to fuel ratio. Sure it is a voltage output but you would have to have some way of interperting? what the voltage outputs represent and say you got a reading of .76 volts?? So what do you do with that???
Gene break open the piggy back and buy yourself a fathers day present. That time is fast approaching.:thumbsup:
 
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