Turbobricks-inlägg om LH 2.4 – manipulering

[big nyz]

big nyz

januari 15, 2014 kl. 21:06 #26370

Hej LH-intressenter!

Jag gör mitt bästa nu om kvällarna för att så långt som möjligt nörda in mig i LH, eftersom jag håller på och bygger en BMW 1502 med turbomatad B212-motor och LH 2.4.2 och EZK.

Jag hittade en intressant tråd med ett extra intressant inlägg på turbobricks för ett par dagar sedan som jag läst några gånger och försöker förstå. Det är dåligt skrivet, men detta är ungefär vad det verkar handla om:

Killen har LH 2.4 i sin Volvo, och kör 420cc Supra-spridare (jag vet dock inte om det är väsentligt). Han har kommit på ett sätt att manipulera LH så han har lambda 1 när LH går enligt lambdagivaren – men vid WOT och höglast så fetar den på med lambda 11.1! Detta åstadkommer han genom att att sätta en potentiometer på signaltråden från LMM till ECU:n. Han pluggar ur lambdasonden då bilen går på tomgång, sitter och kollar på sin bredbandslambda och skruvar på poten tills han hittat det lambdavärde som han vill ha vid WOT. Sedan kopplar han in lambdasonden igen och låter bilen stå och adaptera systemet. Då kommer alltså bilen att gå på ”rätt” lambda medan den går på lätt/dellastmapp, men på fullast går den enligt de manipulerade värdena…

Tankar om detta, experter? Signalen från LMM är ju på 1,4 – 5V, från tomgång till max. Med en lämplig pot borde man ju åtminstone i teorin kunna åstadkomma ”rätt” blandförhållande på dellast med större spridare, utan att bygga större LMM-hus. Men då når man ju aldrig fulla 5V? Det är något som haltar här, men jag kan inte riktigt sätta fingret på det…

Dock så är tanken intressant.

Jag har också hittat en teori om att koppla in en pot på signalen från tempgivaren; man kan då få motorn att tro att den ännu är kall, så den tillåter en fetare blandning. Det idealiska här vore ju att komma på en funktion som bypassar potentiometern vid dellast, men ”sänker” temperatursignalen då laddet kommer….

Tankar?
Mvh,
Mathias

Ps.
Här är inlägget på Turbobricks:

The idle is not the problem-the ecu will learn in a matter of a few minutes just how much fuel is needed/not needed to keep the car idleing smoothly. The ecu will have to be reset by unplugging the battery or pulling fuse. Then you will have to crank it a few times to get the o2 sensor warm before it will start adjusting the fuel curve to smoothen out the idle. The first time i did this it took almost 10 minutes to get the car started (the o2 sensor is cold people!). Dont be discouraged-its normal learning process. Then you will hear the motor making changes and the idle will smoothen out after about 2-10 minutes.
The problems start when you go drive the car and you start hitting boost-or high revs-because then the 02 sensor basicaly switches off and the ecu pre programmed fuel maps take over, obviously if the maps were perfect for smaller injectors-they will be too rich now with larger-so you fool the source that tells the ecu what map to run off of. You do that by buying a Potentiometer from radio Shack or the like that has an adjustable knob that adjust from 300 to 10k ohms i believe (dont have the package or part number in front of me ) , expect to pay a bone breaking $3.50 for this fully adjustable vpc-afc whatever you feel like calling it. I call it the ”new Hotness”, because now you have the fuel to run whatever turbo size you want within reason, with the exception of boost cut. I have found that with an npr isuzu intercooler (had it on for a few days now along with t cam-WOW what a difference!) that my usual 15psi went down to 12/13 psi with the intercooler swap(tube and fin on in and outside causes pressure drop=thus better intercooling affect as air slows down to be cooled then speeds back up as it radiates the heat to the outside. The stock volvo intercoolers dont have hardly any pressure drop- however heat up very quickly and dont intercool much of anything after about 10 seconds of hard boost, because there are no fins to dissapate the heat from the boosted air inside the tubes on a stock volvo intercooler-thus less intercooled effect=less pressure drop. THe isuzu is a trade off-alot better intercooling affect-however the motor sees less boost at the same wastegate adjustment. BUT the air mass meter still reads the same. All this means that boost cut comes in quicker. Ive heard people say that the l.h 2.4 doesnt have boost cut-BS-it does. I heard other say it comes in at 18psi-that i believe on a stock car. Mine comes in at 14.5-15 psi with the npr in and supra injectors, t3 super 60 thunderchicken turbo-na b230f with later 90+ manifold and a few other things. Its not spark cut either-its fuel, just like on the supra-which i found out the hard way useing a fuel controller (only fuel ) from haltech, car revs till it runs out of fuel or blows up or gets too rich. The pulsewidth is usually ramped way up to bog the motor then leaned out a touch to give that rev limiter sound-and Black smoke emits from exhaust, like i said i know this from experience and can now program a rev limiter on my haltech(s) by only reprogramming the fuel side of things. It saves the motor But at the same time is very annoying if your turbo starts getting into its sweet spot at 15 psi!!! I dont know yet how to eliminate the boost cut or if it can be . I sure would like to find out though!

Ok back to the subject at hand. UNplug the o2 sensor after car idles for 10-15 minutes and it smooths out-youll hear the motor ramp up and down and the o2 sensor cyle and the car may even cut off once or twice trying to ”see ” what fuel it needs at idle. Its perfectly normal. These are big injectors-just be happy you dont have to adjust fuel for the idle part throttle situation-its the hardest to tune-so be happy and sit back and admire the work the volvo ecu takes off your shoulders! After it idles smoothly for about 5-10 minutes, unplug the o2 sensor-the car will fall on its face-and cut off-just to prove what i said is true. Plug back in.
Get a potentiometer from Radio shack-solder it in the signal wire from the amm back to the ecu. Restart the car with the potentiometer bottomed out at its lowest setting(full rich)1 ohm or so. Wow it still idles the same-WERD! Now have a buddy turn the pot or sit in the car and watch your air fuel gauge-wideband-whatever, and start the pot at a baseline 100ohms (use voltmeter and record your results evrytime you adjust the pot-it will help you toruble shoot other problems later like boost leaks and such) Get a tube of super glue and keep it handy along with fingernail polish.The super glue holds the knob from rattling to a different setting-you will find the knob is VERY VERY sensitive. Use polish to get the super glue off for and readjustmenst or fine tuning.
For adjustmenst i use this method- let the car run for 10-15 minutes, unplug o2 sensor from ecu-two plugs on firewall-with car running-if car stalls -its too rich or too lean, readjust pot-try to start twice-if no good-plug 02 back in as to not flood the car-restart-readjust , unplug o2, check air fuel ratio. The whole purpose here with the car idleing is to get the air fuel ratio where you would want the car at if it were at full boost at redline, i personaly like the 11.1.1 range -but wouldnt go any leaner than 11.9 for a turbo car-thats my preference-to each thier own! So adjust the pot so that the car tries to idle at 11.8.1 a/f ratio or if you have a air feul ratio meter(autometer) set it where it runs 1 led in the green at idle-this equates to 2-3 leds green at wide open throttle(wot) at full boost. Plug your o2 sensor back in , take car for test drive. I cannot stress enough to TAKE IT EASY FOR THE FIRST TEN MINUTES OF DRIVING, the ecu and o2 sensor will be communicating back and forth and the ecu will still be learning the fuel curves for part throttle reg cruiseing fuel maps-so take it easy-let the ecu learn, no boost at first-go uphill -downhill-turn all accesories on-lights-the whole nine and give the car the worst situation possible so that it will know what to do when you do use all the accessories and drop the voltage to the pump by half a volt or so. load the car down with as much wieght as possible for the worst situation-to absolutely make sure that it learns correctly the first time! You dont have to take these precautions but i choose to and my car has been awesome( neck and neck with 20psi half assed programed stand alone mr2 saturday night-when i was bouncing off fuel cut-grainger valve issue!), and i drive it every day hard as hell.
Slowly ease into boost-start at 5 psi , you will notice that your air fuel gauge will cycle on up to about 3-5psi then it should go 2leds or more in the green-i accept no less under 15psi-full boost. Start out on a flat road then load weight into the car or find the steepest road you can find and test up the hill with complete caution for you-your car and everyone around you. Then graudually get into more boost if you like what you see. Check your air fuel ratios-wideband. Then glue down when its where you want it-let sit for 30 minutes for glue to dry and it shouldnt change unless a boost leak develops or other mechanical issues.
FYI i have used this setup for about 6 months now on my stock b230f motor with a t cam, have driven to Virginia from Texas, all around Va, then to North Carolina-then South Carolina, dynoed -got my air fuel ratios somewhat correct but had turbo backing off exhaust manifold-then drove back to Texas. So far i have put approximately 10,000 miles on this motor setup (it probably already had 100,000 on the motor when i got it used) and i havent had to do anything to the motor except cam replacement-and that was by choice. The m cam just plain sucks. The compression on the m cam was 230 on each cylinder-my compression with the t cam is 150 on each cylinder. BIG difference! Top end is very amazing now and i have more useable power-where as with the m cam-at full boost at 3200 rpm the rear end was just lighting the tires up with all that torque which quickly went away as revs increase. With the t cam-the effect is quite opposite. Tons of high end torque, good na power down low.

I take no reponsibility for any damage caused by any reason, for anyone tying to duplicate above procedures and mods without my supervision 😉

http://home.comcast.net/~volvo4life/Index.html

dYNO- air fuel; ratio with pot and 430cc supra injectors-this is my desired air fuel ratio for my 9.7.1 compression ratio-M cam

Kris Weldy

http://www.turbobricks.com/forums/showthread.php?t=23902&page=3

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