Boostshakalaka

well, i had a couple people ask me about my bfi, and since i was swappign MAF's with my mom's 94 LS400 tonite, i decided to snap some pics for you guys... cuz a message board is all about sharing information.... right?

all it is basically is the original BFI
http://www.planetsoarer.com/BFIDIY/BFIDIY.html

with a bellmouth around the big hole instead of 3 lil ones like on BFI3 http://www.planetsoarer.com/BFI3/bfi3.htm

the rounded ballistic bellmouth theory is explained here
http://www.autospeed.com/A_1266/cms/article.html

well, here's some pics without the front heat cover


as for the LS400 MAF... i read somewhere on here that it helps out alot... nobody posted much about it. but i thought i'd give it a try anyways. my mom has a 94 and drives way too slow to need a MAF as fancy as her's so i volunteered her to donate to my cause... meet the donor


i got pretty confused, the 4 holes on the LS400 MAF are about 1mm or 2mm smaller than the ones on the SC300 one... so i cant the LS MAF to fit on the 92 SC300 airbox

here's the SC300 MAF(i think the previous owner tried to make the SC eat pebbles or something... thats a nasty *** dent)


here's the LS400 MAFnotice how small them lil screw holes are compared to the MAF from my SC


well, after sitting on my *** for an hour throwing flip flops at moths, i decided to just swap out the sensors, to my suprise, it actually feels like it helps out some, although i think it might just be psycological, the power band is really jerky in 1st gear, and it pulls really hard right after it shifts. i didnt reset my ECU yet, maybe after i do that, the powerband will smooth out... if anybody here has done the LS400 MAF, please let me know if i did it right. thanks

aliga

iTrader: (147)

One question is putting a 400 maf on a 300, is it safe? You are taking in more air, but do you have enough fuel?

Vegassc400

If he resets the ECU it should "learn" the new air/fuel ratio and deliver the extra fuel. At least in theory.

boredguy77

no no no and no. The computer cannot and will not compensate for 25% more air!!! he needs to put 25% bigger injectors on to accomplish anything!!! If you are doing this and you are not either turbocharged, or using nitrous you are wasting your time. the ls400 maf does not give you HP it just allows you more fuel. Also That screen in front of the maf is needed to create the vortex for the maf to correctly make readings! with a big dent in the front I am not sure if it can correctly make readings. I would quickly return to the stock maf and read up on mods before I do them in the future.

Boostshakalaka

SC300T

Ouch!

Bordeguy is right, switching to a larger MAF without proper fuel control will throw off your air/fuel ratio. Toyomoto said you can just put the SC300 maf sensor into the LS400 maf body to realize the same benefit that you're trying to get but you still then need bigger injectors to match.

The maf is just sending a voltage to the ECU that corresponds to x amount of air. (there is an air temp signal also). You have five wires, two for the intake temp, one for ground and two for the actual airflow signal.

It works like this:
You have "x" amount of air moving through the maf, your voltage output "y" to the ECU.
If you increase the size of the MAF by a factor of 1.3, you still have "y" voltage going to the ECU but now you have "1.3x" air moving into the engine. The ECU is still gonna fire the injectors at its normal rate, its based on "y". You are going to have 1.3 times the air per amount of fuel. Therefore your air/fuel ratio is out of whack.

It just so happens that the 440cc injectors flow about 1.4 times more fuel for a given pulse from the ECU. If you install these bigger injectors, the formula balances itself out in the end.

The S-AFC fuel controller modifies this "y" output to the ECU, and it is adjustable by +50% and -50%, so you could probably buy the larger maf body and adjust the S-AFC to be back in the correct fuel trim.

Boostshakalaka

well, sounds like its about time to go get me a safc.... btw, does anyone know the size of mr2 turbo injectors? also, is there anywhere in vegas i can get the safc dyno tuned?

Vegassc400

Try Factor-X out by the speed way. I'm pretty sure they have a dyno.

ps. Sorry about the wrong info. Wasn't trying to get you to blow your car up.

Boostshakalaka

it's cool dude, i had to learn some way lol, plus, if the motor blows up, it's jus incentive for me to go GTE and the V160 right?