76MM C&L volts goe up when RPM goes down
 

Hi Tuners, I have been chasing a problem and I think I have discovered a significant clue. Normal idle is 800 RPM, about 22 KG/HR, .7 volts.

When the fan comes on, the engine usualy dies. I data logged this and saw that the MAF voltage went up as the RPMs went down. see below

RPM 800 700 600 500 400 300
MAFV .7 .71 .72 .78 .8 .85

Maybe it's time to give up on this C&L meter and go back to stack or a Pro Air meter.

Input?

Thanks, Eric

Ditch that junk meter. Italian and I have seen at least 3 of these 76 meters cause problems. One of them being on his car. It was very erratic and hurt his power.

Swap over to a PMAS 80mm and be done with it

Yeah, when I had my C&L, I gave them the benefit of the doubt and tried to make it work. I ran into way too many consistency issues and MAF wash problems. I finally ditched it in favor of a Pro-M univer (which worked a lot better). Now I run a PMAS Velocity meter and love it!

Agreed. Getting the C&L to be in a perfectly directed stream is the only way for it to work. Too bad it's nearly impossible to achieve this on our cars.

The sampling method is just too sensitive on the meters IMO...especially if you have a bunch of stuff done to the car.

Do you have a specific recommendation to replace the 76MM C&L which, I think is 3" in/out?

Eric

The 80 like they use will be fine. They've tested it and it's not giving any troubles. Also, if you can find one, the old ProM 75mm is a great setup. May be a different name now.

Yeah, call Anderson Ford Motorsports for a PMAS meter. That's were Lee got his 80mm and I got my 95mm. Real good people and pretty good price.

yep. the PMAS 80mm MAF will work fine. I have been very pleased with mine.

I've had excellent results with the C&L w/tuner tube - it draws air from the center of the airstream using a venturi effect - much better than the straight-through sample tubes. Can measure to 2700 kg/hr on my 80mm meter as well. I am impressed with how clean the signal is and how I have not had to adjust the provided MAF curve at all.

Edit: BTW, the voltage rising as the engine dies has nothing to do with the C&L tube, though the electronics may be messed up. I would guess the fan coming on (electrical) and the voltage to the MAF varying have something to do with the problem. Blaming the "meter" is not logical really since the 70mm Cobra meter uses a straight-thru tube just like the C&L and the same electronics (slightly different calibration).

That's interesting. Is this something that C&L sells? Sounds like a good idea, but they should've got the word out if they were fixing a problem.


The Cobra MAF isn't much better. For close to stock motors, those meters do fine, but it seems like I had more and more issues as the mods went up.

The PMAS 95mm Velocity meter that i got has a similar straight-thru sampling but the meter is ultra accurate. It's designed very well. :nice: