lm-1 or gunson for 75 cis?

[47silver]

which setup should i use to set my mixture? I want to buy one of these to tune the car and am not sure I am getting the right device. My 75 cis does not have an o2 sensor. is air flow ratio of 14.7 the way to go or should i do it with co? does the lm-1 have the abillity to do co? t
the car is running great now but i am not sure if it is in the rigth range. i did set it up using the air flow sensor lift up and down until the engines idle falls in both directions but i am not cozy with that setup.

thanks

gary

[89turbocabmike]

Gary, I would suggest the LM1. It is more expensive, but it would allow you to check your mixture throughout the driving range, ie. idle, cruise, WOT. There is a chart around that converts O2 to CO. I'll see if I can locate it. I've been very happy with my LM1.

[47silver]

mike
then o2 is the way to set it up?

if you have the data on the conversion i would appreciate it.
thanks


gary

[bigchillcar]

any idea on price for either of these? i find myself frequently recommending gas analysis, but don't know what prices to advise to expect should someone wish to purchase their own..
ryan

[47silver]

the gunson is about 200 on ebay the lm-1 is about 400 and depends on which options that you get.
i

[anthony]

Innovate also makes the LC-1 for $200. I think you can hook it up to a laptop to get readouts.

[89turbocabmike]

Here's the link to the chart:

http://www.perfectpower.com/Technical_info/afr.asp

[aigel]

LM1! I have it. Works great and very versatile.

George

[47silver]

I think that i will go with the lc-1 and use the conversion for co and manually adjust.

thanks

gary

[aigel]

I set mine at 13.2 A/F ratio.

George

[47silver]

13.2 = 3.5% CO, which is where JW I believe recommends adjusting it too. Thanks a million i appreciate the information.

Gary

[47silver]

I just checked out the LC-1, looks like the tool i need, but can it be accurate at the exhaust tip as my system does not include an exhaust tap for the o2 sensor? It may need a heater to operate?

gary

[304065]

The heater is integral with the oxygen sensor.

You can also buy a tailpipe adaptor to work with the LC-1 for a temporary installation. However, it's a simple matter to have a muffler shop install a stainless steel oxygen sensor bung somewhere in your exhaust system, for a permanent installation.

Search under my name and LM-1 for details of doing this in an early SSI car.

[aigel]

what john said. Innovate sells stainless and regular steel bungs.

George

[47silver]

decision is made then
lc-1

[klatinn]

Hi,

Just so you understand:
The LC-1 is intended for permanent installation for AFR measurement only. It does not have a display or the simple cigarette lighter plug of the LM-1. You have to make your own 12V hookup. It also does not have the other LM-1 inputs nor does it have internal datalogging without laptop.
You can program one analog out to drive a digital multimeter (or panel mount 2V voltmeter) as display though. Program to 1V = 10AFR and 2V = 20AFR and then mentally shift the decimal point.

Regards,
Klaus

[aigel]

Klaus:

Thanks for clarifying. I recommend the LM1 over the LC1 then. It is more versatile. If you have any other cars in the stable, especially anything with a carburetor, you'll want the LM1. You can still permanently install the LM1 if you are inclined to do so.

Cheers, George

[klatinn]

Hi George,

Yeah, alot of people think they can just buy an LC-1 and have the same functionality as the LM-1 for less.
The LM-1 is a tuner product for tuning cars. The LC-1 is purely a wideband controller for aftermarket ECUs (or to fool stock ECU's, incl. Lambda computer for CIS), monitoring AFR, dyno's and as part of a larger datalogging system. Within the next few weeks we will have new firmware for the LMA-3 (and possibly, if required, for the LC-1) that allows you to daisy-chain ALL devices, including LM-1 to build a datalogging system of up to 32 channels.

Regards,
Klaus

[47silver]

Thanks everyone:
Although the LM-1 would be the best overall device, i think that for my application it would be overkill, as all that i want to do is adjust and/or verify the mixture maybe 2 times a year. The LC-1 appears to be my best bet as it will allow me to access the information from a laptop or connect it to an analog input in one of my controller boards. My controller boards accept up to 16 universal inputs (digital or analog) 0-5 VDC or 4-20ma and each input is scalable with up to 16 bit resolution. they also have up to 12 universal scalable outputs, 0-12vdc 4-20 ma that can drive meters etc.

I did think about a system where i used one of the PID loops in the controller board to modulate a minature actuator, the actuator is connected to the mixture screw through an gimbaled floating allen key shaft through the mixture adjustment hole (strictly bolt on). The board would could control the mixture screw to continuously maintain setpoint at the optimal AFM or maybe just adjust it every so many minutes. I suppose that this would pose many problems and that is why i have not implemented it.

thanks again

gary

[klatinn]

Hi,

There are much easier ways to electronically control a CIS:

a. Regulate control pressure. That's how it's done on a CIS-E. The WUR regulates it based on temperature (and on some) based on MAP. An electronically controlled pressure regulator in parallel to the WUR would allow closed loop AFR control.

b. Regulate pressure in lower chamber of metering valves with a duty-cycle controlled bypass valve (frequency valve). That's how it's done on CIS Lambda. Get a CIS Lambda fuel distributor and frequency valve and you can easily build a closed loop fueling system with a WB controller like the LC-1.

Regards,
Klaus