When you aredriving along and taking readings how much do your readings swing. I am cruising along today and Iget from a 13.8 to 14.2 trying to keep the throttle as steady as possible. At idle do your readings swing some also. I know with the cam I'm running I will get some swing and my vacuum sucks, (pun intended) about 7 to 8 inches so this might have some bearing on it. My co pilot has not been with me for a few rides and I want to see what it is under WOT if it stays fairly steady. I need to hook my laptop back up also.

Leaning the idle circuits out some seemed to help out. I am still getting under hard braking a load up of fuel. It drops back into the 11s under a hard brake and almost dies on me.

 

mine will vary at least 0.2 - 0.3. i think that is as good as mine will get.

 

IF you are watching the LM1/logworks live via laptop or the display on the lm1, you will get varying readings slightly. The LM1 samples so fast there is no way AFR will stay steady. Even if trying to hold the same throttle position and rpm, it will still vary and surge. 14.2 is a tad lean and you are probably getting a lean surge. Tune your part throttle/cruise for around 13.5-13.8 at the leanest. Get your WOT at 12.8-13.0. If you use the logger feature it makes it WAY easier to tune. You must get the rpm converter though so you know where you're at.

THe LM1 is like Pandoras box, when you open it up and start playing, it will drive you crazy trying to get it right. I have been tuning my 300rwhp turbo hayabusa with an LM1 for over a year and still can never get it perfect at all throttle % and rpm.

If you have any questions about the LM1, hit me up...I have a LOT of experience with it.

 

Looks like mine only varies about .2 to .3 too here is cruise at 2500RPM for one minute

With the help on the Innovate forum I have my 825 Race Demon dialed in exactly where I want it for idle, cruise/part throttle and wide open throttle I don't even have it connected anymore, it's waiting for the new 427ci

 

ajrothm,
i'll take!! i have a couple of questions:

the old beater has an old points type dist. and i can't get the rpm to log correctly. have you run into this, and how to get correct (close enough) rpm values?

the WOT values of 12.8-13.0 agree close enough for me with published material, but what is your basis for the part throttle/cruise recommended values? what would be the problem with leaner and leaner values? have you by chance checked the mileage difference cruising at 13.8 vs say 14.7-15.0?

also, what range do you shoot for at idle?

thanks . . .

 

IF your motor is like mine it starts to miss at cruise with a higher A/F ratio. I had mine at near 15:1 at cruise and while the gas mileage was great my motor just did not run right it would miss and surge. HIgh performance smal/big block chevys like it rich so you have to tune to what they like which is gonna cost you on gas consumption.

So I am at ~13.5:1 at cruise and near 13:1 at idle if I remember correctly

 

Ok I guess I'm pretty close. I felt I was a little rich at the lower rpms and cruise so I leaned it out some. I do have the rpm converter and have logged a few runs and it seems pretty smooth on the graph. My WOT is right at 12.5 to 12.8 and on the chassis dyno it lost a few rpm by going richer tha nwhere it is at. I have just messed with the idle screws a little to clean up the idle a little.

 

MotorHead, mine is varying between about 14.6 and 14.9 cruising after quite a bit of work i might add, and doesn't seem to mind; not experienced any missing yet. the plugs were black from a too rich mixture (started with carb all over the place from < 9:1 to 12:1) and now look much better, no signs of too lean yet; still check periodically. engine now has about 600 miles. i don't know how much difference it would make in gas mileage to back down to the 13s, but i'd guess at least 1 mpg (it's averaging about 11.5 mpg now, 12.3 was best). It also idles at 14.7 (more like bounces around 14.7). i can turn the mixture screws to make that 13s or whatever, but that seems too rich. there is still work left on the secondary side (too rich)-will get some more miles on engine first. i'm conviced now that the milage is about as good as it will get 'till a 4th gear appears. might get it to run a little better. . . thanks for benchmark comparisons!!!

anybody able to get the rpm to work on the old dizzy's???

 

Gordon, are you running jet extensions in the secondaries? It may be the fuel is moving forward in the rear float bowl and overwhelming the jets or just causing it to run over. Just a thought.

 

That's about the same as mine. What does your display look like? Mine is the kind with the black boxes and a lot of the time it's just a blur. My Holley ECU apparently averages the readings...

 

i wish i could find a better pic:http://www.motorsportsinnovations.co...0b%20large.bmp

 

I think I read in my LC-1 document that you can adjust the sampling rate.


Edit: Actually it's in the Logworks PDF under logging speed.

 

No I don't. That is what I think is happening. The LM1 shows it going rich under hard braking. I can throw it in nuetral and coast for a while and it is OK then jump on the brakes and it goes rich.

I got mine to work with the old dist but I am running a Crane box so the setup is different.

 

Mine is still i the box. I really need to get this thing out and play with it. I can still get this motor to run good and then use it on the LS1 when the time comes, I think. Maybe tomorrow night I will see if my neighbor can do a little welding for me.

 

I assume you are using the inductive clamp for RPM pick up. The LM1 is so sensitive it will detect ANY small ignition miss and it will result in slight up and down spikes in AFR and sometimes crazy RPM readings. A weak plug or plug wire often causes these weird spikes.

Also if your rpm readings are way off, you may have your channel configured wrong in log works or you have the wrong amount of cylinders selected. I am not sure if you are using the RPM converter or the LMA3 but...

Your best bet is to go to www.innovatemotorsports.com and go to the forums, register and throw a post up to Klaus, he will get you straight.

One key point for all you LM1 users is after you are done tuning, remove the O2 sensor. The Bosch sensors don't really like to live long in rich conditions(normal for carbed, old school motors, 12.5-13.5 afr) and the sensors will crap out. I just killed one on my bike, it runs really rich all the time. I run it at around 11.8-1 AFR at WOT and 12.5-13.0 to 1 at part throttle/cruise. Idle is around 12.5-1 at cold start and after warm up leans out to around 13.2-1. I could lean out the idle a little more but I basically tuned it like you would a carb, I adjusted AFR to get the highest idle speed when warm, it likes 13.2 the best.

Keep in mind, new fuel injection cars, especially closed loop LS1s can cruise at 13.8-14.2 to 1 and the sensors last forever. The sensors are designed to run close to stoich at 14.7..The farther away from stoich they get, the less they last.

ANYTHING leaner then 14.7 to 1 is definetly too lean and much more prone to detonation. I have not tuned my old car with the LM1, only my turbo bike but the principles are the same. My LS1 car is tuned to 12.9-1 AFR at WOT but not sure about the part throttle and cruise. LS1s run closed loop all the time, I would imagine its in the 13.8-14.0 range. Thats manageable with an ECM controlling everything, not a q-jet and a set of points like my 71 vette.

 

In most of the country, the pumps are putting out 10% or more ethanol (gasahol). The standard stoichiometric ratio is now closer to 14.1-14.2.

 

While i don't have an LM1 or any oxygen sensor my thought would be the amount of Oxygen in the exhaust would be the same for a correctly tuned engine running either petrol or gasahol, therefore the reading would be the same even though the stoich ratio has changed.
Is my thinking flawed?
Does anyone have any real world experience to prove or debunk my theory?

 

thanks ajrothm, i'll do more checking. i haven't been using the inductive pickup-that may be the problem? i went through the configuration, and think that is okay. i just hooked up the RPM converter like i would the cheap tach-dwell meters, to the dist side of the coil, then tried using the software to correct. will go to the innovate side as suggested . . . thanks

RHD '68 L89, i think you answered your own question. if stoich changes the oxygen available to read will change, but i have no real world experience. can look for stoich combustion equations and compare mass % O2

 

This could also be that you have your float level set too high. You may want to try lowering it a little.

 

Even so, the LM-1 will still show 14.7. It measures lambda and assumes lambda 1=14.7. Even though lambda 1 has changed with the 10% ethanol, the LM-1 still uses 14.7 so your display will show 14.7 when in reality it's a bit richer.