air /fuel meters and tuning



air /fuel meters and tuning

Postby paul » September 26th, 2008, 11:45 am

thats a good question for this forum,
Ok Ive got one and have tested several of them.
I YOUR HAVING ISSUES< WITH THE CAR RUNNING CORRECTLY,LOOK FOR LOOSE OR CORRODED ELECTRICAL WIRING CONNECTORS, in THE WIRING HARNESS, and VERIFY YOUR FIRING ORDER, YEAH I KNOW YOUR SURE ITS CORRECT, CHECK IT CAREFULLY AGAIN, YOUR NOID TEST LIGHT AND MULTI- METER CAN SAVE YOU A GREAT DEAL OF PROBLEMS AND SCRATCHING YOUR HEAD IF YOU TEST BASIC ELECTRICAL CONNECTIONS< RESISTANCE AND VOLTAGE, CHECK YOUR SENSORS AND GROUNDS, A SHOP MANUALS MANDATORY, HEAT SENSORS AND IGNITION MODULES AND OIL PRESSURE SENSORS HAVE A LONG TRACK RECORD OF FAILING OR PARTIALLY AND INTERMITTENTLY NOT FUNCTIONING
Image

http://www.autometer.com/tech_faq_answe ... d=1&qid=48

http://www.innovatemotorsports.com/products/lm2.php

http://www.jegs.com/c/Gauges-Tachs_Air- ... 5/10002/-1

http://www.lethalperformance.com/05-201 ... io-p-18965

http://www.aa1car.com/library/wraf.htm

http://www.modernperformance.com/product_info.php?manufacturers_id=&products_id=1149

http://www.3barracing.com/product_3.htm

http://www.rbracing-rsr.com/rsrgauge.htm

http://www.scirocco.org/tech/misc/afgauge/af.html

http://www.innovatemotorsports.com/products/lm1.php

http://www.autospeed.com/cms/A_0217/article.html?popularArticle

http://thedynoshop.net/prod01.htm

heres my take on them, short answer, they are a big help but a P.I.T.A. to set up and use if your not going to semi permenantly install them on your car.

Image
IVE come to use reading spark plug condition,

http://www.digitalcorvettes.com/forums/showthread.php?t=80783

http://www.digitalcorvettes.com/forums/showthread.php?t=85537&highlight=plugs

use of a good timing light and vacuum gauge , fuel pressure gauge and use of a GOOD HIGH TEMP INFARED THERMOMETER (THIS ONE)

http://www.professionalequipment.com/extech-high-temperature-infrared-laser-thermometer-501-ds-42545/infrared-thermometer/

as a very quick to use and accurate set of tools. :thumbsup:

OK WHY???

well your main concern when tuning an engine is to keep the all the cylinders running aproximately the same ratio and at about 12.8:1 for max power up to about 14.7:1 for low emmissions and good mileage, AND WHILE A A/F GAUGE IS A GREAT ASSET, ITS EASY TO DAMAGE, AND ITS BEST INSTALLED IN YOUR CAR , NOT USED AS A SHOP TOOL.

so whats the advantage/disadvantages

a fuel air meter uses a o2 sensor, if you place it in the header collector it gives an AVERAGE of all the cylinders on that cylinder head,If theres an (X) installed close to the dual collectors reversion pulses can occasionally even give data from the other side of the engine, so in theory and in practice you can have two cylinders run lean and two rich and the AVERAGE tends to look RICH to the O2 sensor as it SEES unburnt fuel, if you place it in the individual primary header tubes you either need eight O2 sensors (VERY EXPENSIVE, and keeping the wires from burning or grounding outs a TOTAL P.I.T.A......IF you don,t succeed you destroy the O2 sensor and need to replace it.) or you need to be constantly swapping very hot and fragile O2 sensors and bung plugs constantly, but with the IR thermometer you can almost instantly see which cylinders are running hotter or cooler and adjust the jets or look for vacuum leaks, or other CAUSED for the TEMP DIFFERANCE, ETC, far faster too get all the cylinders running at approximately the same temp, indicating the same fuel air ratio, youll be amazed at how close the temp follows the fuel/air ratio, and you can confirm it with plug condition and the other test equipment. run any cylinder too lean and detonation can break rings or melt pistons, run it too rich and you can wash the oil off the cylinder walls and ruin rings/scuff pistons, you need to know whats going on in EACH CYLINDER not the AVERAGE of all cylinders.

SO, if your going to install a decent wide band fuel air ratio meter on your car thats fine, its going to be an asset to your tunning skills, if you install the indicator/gauge inside the car and weld in a couple extra bungs in the collectors for tunning and wide band O2 sensors which are a big help, but you will quickly find that its a P.I.T.A. to use it for tune ups on all your buddies cars with the welding collector bungs and installing plugs and O2 sensors while the IR thermometer route is fast and very simple and you can confirm with oplug reading the condition of the engine.

YEAH! theres meters that you can stick in a tail pipe, but they read THE AVERAGE, not the individual cylinders ,
think about AVERAGEs
AS my old physics proffesor once said,
IF, I pour molten lead in your front slacks pockets and pack your butt in solid with DRY ICE,.... ON AVERAGE your comfortable:D


BTW
http://www.digitalcorvettes.com/forums/showthread.php?t=79676


bits of useful info on these

http://www.thirdgen.org/o2tuning

http://www.thirdgen.org/fuelgauge

http://www.thirdgen.org/tpimod2

http://www.thirdgen.org/injectorswap

http://www.thirdgen.org/coolantbypass

http://www.mummbrothers.com/SRF_Stuff/Secrets/Driveline/Air_Fuel.htm

http://www.ws6.com/mycar.htm

leon posted this bit of info
"Exhaust gas temperature (EGT) depends on combustion temperatures. The hotter the mixture burns inside the cylinder, the hotter it will be coming out. Theoretically, combustion temperatures are at a maximum at stoichiometric, but realistically the maximum occurs slightly rich from peak because of the dissociation of Oxygen from the combustion products (CO2, H2O). Why temperature drops when rich or lean is described by the energy released caused by the chemical reactions between the fuel and air. Too little fuel (lean) and there is less energy contained within and more heat is transferred to the cylinder walls (no fuel evaporation or boundary layer), thus the lower temperature when it burns. Too much fuel, and combustion efficiency drops thus generating less heat.

I know, this is not too detailed, but it gets the point across without involving too much technical jargon.

Of course, this all assumes MBT timing and stable combustion. You can also change exhaust temps by varying spark timing, arguably more so than by just varying AFR. EGT is increased when spark timing is retarded since you are giving the gasses in the cylinder less time to cool off before the exhaust valve opens. "
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Re: air /fuel meters and tuning

Postby grumpyvette » November 29th, 2011, 7:56 am

Excessive HC emissions may be caused by:

viewtopic.php?f=55&t=3522&p=9307&hilit=emissions#p9307

ignition system misfiring
Improper ignition timing (retarted)
excessively rich air/fuel ratio
low cylinder compression
defective valves, guides, or lifters
vacuum leaks

Excessive CO emissions may be caused by:

rich air/fuel mixture
dirty air filter
faulty injectors
higher-than-normal fuel pressures
defective system input sensor

Excessive HC and CO emissions may be caused by:

plugged PCV system
excessively rich air/fuel ratio
stuck open heat riser valve
AIR pump inoperative or disconnected
engine oil diluted with gasoline

Lower-than-normal O2 readings may be caused by:

rich air/fuel mixture
dirty air filter
faulty injectors
higher-than-normal fuel pressures
Restricted PCV system
charcoal canister purging at idle and low speeds

Lower-than-normal CO2 readings may be caused by:

leaking exhaust system
rich air/fuel mixture

Higher-than-normal O2 readings may be caused by:
an engine misfire
lean air/fuel mixture
vacuum leaks
lower-than-specified fuel pressures
defective fuel injectors
defective system input sensor
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: air /fuel meters and tuning

Postby DorianL » November 29th, 2011, 10:51 am

AND WHILE A A/F GAUGE IS A GREAT ASSET, ITS EASY TO DAMAGE, AND ITS BEST INSTALLED IN YOUR CAR , NOT USED AS A SHOP TOOL.

Really - I should keep my dual wide band O2 in there premanently? That's best for it? I yanked it out concerned that I might harm it. Would not mind having it in permanently...
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Re: air /fuel meters and tuning

Postby grumpyvette » November 29th, 2011, 10:56 am

obviously theres a wide variation in quality and most modern cars with EFI use oxygen sensors used in the exhaust of cars to do this type of sensor work and NOTHING ELECTRONIC in nature lasts forever,but the sensors are used to feed constant data on remaining un-burnt oxygen in the exhaust back to the computer controlling the fuel injector pulse duration,yes in some cases its potentially possible to damage the sensors, sensors normally last 3-6 years in service, but in most cases its not critical if properly installed , and not all that expensive or time consuming to replace them on occasion,so its not a big deal to suggest a dash mounted fuel/air ratio gauge be used as a tuning tool on a carburetor equipped engine, there even several BUILD IT YOURSELF F/A RATIO GAUGE KITS AVAILABLE

http://www.scirocco.org/tech/misc/afgauge/af.html

http://www.aces.edu/~parmega/efi/temp/wb/guide.html

viewtopic.php?f=27&t=3096&p=18612#p18612

viewtopic.php?f=55&t=3522&p=18430&hilit=diy+fuel+ratio#p18430

http://www.autospeed.com.au/cms/A_1716/ ... larArticle

http://www.autospeed.com.au/cms/A_0217/ ... larArticle

http://www.jaycar.com.au/productView.as ... BCATID=347

http://www.eagle-research.com/cms/store ... cer-manual

http://www.youtube.com/watch?v=sS6olf1o ... ure=fvwrel

http://www.youtube.com/watch?v=RizrDvP8 ... re=related
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: air /fuel meters and tuning

Postby DorianL » November 29th, 2011, 11:00 am

With a blower, I wanted to be extra caerful...

I picked this up some time ago but pulled it out because I was told by a local leaving it in for daily use might damage it.

Image

http://www.summitracing.com/parts/FST-170402/
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Re: air /fuel meters and tuning

Postby mathd » November 29th, 2011, 11:19 am

Yeah, thats because with the engine running the snesor has to be powered/hot.
Leaving an unpowered sensor in the exhaust will damage it. So if you have the sensor in the exhaust just dont leave it unpowered when your runnig the car and it will be fine(if its setup above the 9-3 O'clock position)
Also, its best to start the unit/heat the sensor just after the engine start, you dont want to cause moisture blast on the hot/heated sensor while the engine is first starting.
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Re: air /fuel meters and tuning

Postby DorianL » November 29th, 2011, 11:30 am

Groan - I guess we'll soon find out if I damaged it. I'll probably leave it in + hardwire. I just need to find a place to put it as dash real estate on my car is getting scarce...
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Re: air /fuel meters and tuning

Postby larrym » November 29th, 2011, 5:20 pm

Here is what I use, and I tune for 10.5 at WOT with 24lbs of boost spraying straight meth on top my regular 94 octane fuel. Its a safe tune some guys will lean it out a bit but I like safe at 24 PSI.

http://www.aemelectronics.com/wideband- ... -gauge-25/
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Re: air /fuel meters and tuning

Postby mathd » November 29th, 2011, 5:41 pm

I'd probably tune at 10.5 a/f me too at 24 psi lol
Better safe then sorry.

Am using this (i did want something that also log the RPM)
LM-2:
http://www.summitracing.com/parts/INN-3806/
I may try to make a TPS (potentiometer/resistor forming a voltage divider)using one of the input of the LM-2.

So far i could try only the OBD-II functions on a newer car, will try it completly next season(april 2k12 is where i plan to take the car out).
Just welded the bung last week and i managed to accidently leave the flange ferrule behind the bung. :/
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Re: air /fuel meters and tuning

Postby Indycars » November 29th, 2011, 7:08 pm

How important is it to be capable of monitoring both sides of a V8 with a single 4-barrel on a dual plane manifold ??? Certainly one is better than nothing, but seems like you are only getting half the picture with one side. Love the idea of data logging, much easier to look over the data when you are NOT driving.

Whats has been your experience, any problems with just one sensor ???
Rick
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Re: air /fuel meters and tuning

Postby grumpyvette » November 29th, 2011, 7:21 pm

while dual sensors is obviously close to ideal and having a dedicated sensor for each cylinder is ideal, Ive swapped sides on the sensors testing my corvettes engine in the past and had very similar results so I doubt its going to be a problem.

heres a tip posted elseware if you don,t want to weld in bungs for testing probes or sensors in your header collectors ,in your exhaust pipes or while measuring the fuel/air ratio while tuning
Image
http://www.innovatemotorsports.com/xcar ... ctid=16141
Image
http://www.innovatemotorsports.com/xcar ... 274&page=1
http://www.innovatemotorsports.com/xcar ... 274&page=1
bytor wrote:Another option is to use tail pipe clamp adapter (3728) on the end of your exhaust. It uses a venturi effect to sample exhaust gas while keeping air away from the sensor. You probably would not wont this setup for a permanent install but it would keep you from having to drill holes. With your short exhaust, I would not see any significant lag or delay in the readings. I have been to a few dyno shops and the all use something like this to capture AFR during dyno runs.

Image
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: air /fuel meters and tuning

Postby mathd » November 29th, 2011, 8:12 pm

grumpyvette wrote:while dual sensors is obviously close to ideal and having a dedicated sensor for each cylinder is ideal, Ive swapped sides on the sensors testing my corvettes engine in the past and had very similar results so I doubt its going to be a problem.

Thats good to hear and you can also make an average of both side reading and in some case you can configure the unit with this in mind, so while you have just one sensor it will display a reading that average both side together.

I did go the single channel route, but the unit is capable of dual channel so hopefully if i buy one more sensor it will work on dual channel :).
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Re: air /fuel meters and tuning

Postby Indycars » November 29th, 2011, 8:29 pm

mathd wrote:I did go the single channel route, but the unit is capable of dual channel so hopefully if i buy one more sensor it will work on dual channel :).

SWEET, twice as many numbers......I wonder what I could do with this and an Excel spreadsheet. I'm starting to get a ???? as I type on the keyboard now! 8-)
Rick
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- Need a Dynamic Compression Ratio Calculator: viewtopic.php?f=99&t=4458
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Re: air /fuel meters and tuning

Postby DorianL » November 30th, 2011, 3:42 am

Indycars wrote:SWEET, twice as many numbers......I wonder what I could do with this and an Excel spreadsheet. I'm starting to get a ???? as I type on the keyboard now! 8-)


Ummmm, Okaaaay! Indy, there is such a thing as too MUCH information... :D

My issue is the instructions on the water/meth say to tune first the carb for slightly lean. (!!!) Say 12:1. Then use the water/meth to tune and hit 11:1 as your target.

THAT seems like a scary way to tune.

I probably will take out ignition timing thru boost retard... reach 12:1 with carb only... add water/meth to reach 11:1... then experiment with pulling out boost retard.
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Re: air /fuel meters and tuning

Postby larrym » November 30th, 2011, 12:46 pm

DorianL wrote:
Indycars wrote:SWEET, twice as many numbers......I wonder what I could do with this and an Excel spreadsheet. I'm starting to get a ???? as I type on the keyboard now! 8-)


Ummmm, Okaaaay! Indy, there is such a thing as too MUCH information... :D

My issue is the instructions on the water/meth say to tune first the carb for slightly lean. (!!!) Say 12:1. Then use the water/meth to tune and hit 11:1 as your target.

THAT seems like a scary way to tune.

I probably will take out ignition timing thru boost retard... reach 12:1 with carb only... add water/meth to reach 11:1... then experiment with pulling out boost retard.


Personally I do it oppositely start with a fat tune and pull fuel or add boost or timing until the knock sensor says I've gone to far than dial it back a bit little safer IMO. With water in the mix 11.0 isn't a bad target just watch the knock gauge.
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60lb injectors with Turbo Tweak Chip
Turbonetics BB CPT 61
CAS V4 Stretch Intercooler
Alcohol Injection
lots of fun with a little 6 banger!
Best ET 11.88
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Re: air /fuel meters and tuning

Postby mathd » November 30th, 2011, 4:34 pm

DorianL wrote:
Indycars wrote:SWEET, twice as many numbers......I wonder what I could do with this and an Excel spreadsheet. I'm starting to get a ???? as I type on the keyboard now! 8-)


Ummmm, Okaaaay! Indy, there is such a thing as too MUCH information... :D

My issue is the instructions on the water/meth say to tune first the carb for slightly lean. (!!!) Say 12:1. Then use the water/meth to tune and hit 11:1 as your target.

THAT seems like a scary way to tune.

I probably will take out ignition timing thru boost retard... reach 12:1 with carb only... add water/meth to reach 11:1... then experiment with pulling out boost retard.

I would probably tune using the Lambda instead of the A/F reading since your blend of gasoline and alchool.
Here is what my instruction sheet says:
The Stoichiometric AFR value is the AFR multiplier. So for (standard, unblended)
gasoline its 14.7. If you set it to 14.7 the LM-2 display will show 14.7 AFR for Lambda
1.0. If you set it to 6.4 (methanol) the LM-2 will show 6.4 AFR for Lambda 1.0.
You can look at Lambda as the percent of richness. If running Lambda 0.85 (12.5 AFR
for gasoline) you are running 15% rich. For methanol 15% rich means 5.44 AFR. That's
where the value of Lambda comes in. If you run blended fuels where you don't know the
stoich value, you look at Lambda and adjust to 10-20% rich, depending where your max
power is. The % value of richness required by an engine (for max power) does change
relatively little (fairly independent of fuel). But if for example you adjust an engine
running methanol to 12.5 AFR, you would be running so lean that it would probably not
even run
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