92mm MAF Report

[skorost]

Many of you know that I am running a lot of boost and have had some trouble with air flow. My previous setup included a Lightning CAI and the stock 90mm MAF. I've been pegging 5 volts from the mass air flow sensor and thus getting some pinging/detonation on cooler days. Today my new Pro-M 92mm MAF arrived and below are some close ups. You can see it is made of steel and that the sensor does not disturb the flow of air in the middle of the tube. Rather, it is offset. Also attached in the image is a flow test that I received from the manufacturer. It can flow 1132.2 KG./Hr. and only reach 4.304 Volts. I'm not really sure what I was flowing before because I don't have any datalog files. If anyone can add to this thread what the stock MAF flows at 5 Volts, that would be much appreciated.

Hopefully this will compensate for my boost setup. (6#Lowers 2.73 upper) I need to fix this before the nitrous goes in. (wet 50 shot)
Cheers,

-Sko

 

[redaddiction]

Is that blow thru maf ?

 

[skorost]

well I came back from a test run tonight with the new MAF and WOW !!! ran through all the gears and gave em strange and unusual fuel demands.... no pinging/detonation whatsoever, just nice smooth glides up the MPH guage. Shweet !

Someone told me there's no way I'd be able to peg the voltage on this thing... I kinda believe it now. But does anyone yet know the flow of the stock 90mm MAF sensor at 5 volts ?

 

[03DOHC]

Pegging the stock MAF at 5V made your car ping?

 

[mm49]

I was datalogging with AutoTap and pegging my stock MAF @ 4600rpm 20lb boost. I recorded 482.22 G/S at 4.99 volts. I think that =1735.99 Kg/Hr if I did the math right. I have no pinging the default tables it goes to during pegging are very rich and timing is pulled slightly. Runs very well!

JL

 

[bassin247]

holy boobies, I mean do you think you can flow enough air through that filter?

 

[skorost]

Originally posted by mm49
I was datalogging with AutoTap and pegging my stock MAF @ 4600rpm 20lb boost. I recorded 482.22 G/S at 4.99 volts. I think that =1735.99 Kg/Hr if I did the math right. I have no pinging the default tables it goes to during pegging are very rich and timing is pulled slightly. Runs very well!

JL

OUCH ! Thanks mm49, good to know. I guess I'll have to datalog mine this week. My timing is 22 degrees and boost is also 20...

 

[lRageATMl]

that filter looks tiny...

 

[Venomous Mofo]

There's really no benefit after 9" is from ive gathered.

So your tune didnt end up a tad bit leaner with the new meter? Sounds good. Wonder if this 92mm will work on the Lightning. No ones had any luck with the 95MM sewer pipe on one.

What was the cost of the unit if i may ask?

 

[lRageATMl]

ahh...that filter looks a bit smaller then 9 inches

 

[Dana]

Since you guys seem to be a little ahead of me on this MAF business, will you please give me a schooling on its function.
I CAN see where a larger MAF will flow more air (by virtue of its larger diameter) at the same voltage or the same air volume at a lower voltage ( I think), but what about the PCM? How does it know that you are doing this or that you have changed the MAF from 90 to 92mm? If you are flowing more air at the same voltage, won't the PCM look at the voltage and apply the original matching fuel tables and therefore run lean?

Thanks,

Dana

 

[Almo]

Interesting. TTT

 

[skorost]

More feedback

Well I ran it some more today and still am having no more pinging but will have to wait until it's a little cooler out to tell for sure. Something I did notice is that with the larger pipe the idle is slightly strugling to steady itself. This is the computer trying to compensate for a little more air than what it is programmed for... It stalled 3 times this afternoon when at lights. I'm no expert on the dynamics of air flow, but I too questioned the fact that this filter is much smaller than my previous one. When I put my hand over it at idle I can feel the air being sucked in, which I couldn't feel with my older/larger filter.

Can we have some input from the venerable tuners in our community please ?

1. What is the KG./Hr. flow of most stock 90mm MAFs at peak voltage ?

2. Does this smaller air filter make a noticable difference in flow capacities ?

3. Does a 92mm MAF with an offset sensor make a noticable difference in flow capacities ? (REF the Flow analysis above)

4. Does the computer need to be programed to command different idles from a larger MAF tube ?

5. Any additional comments ?

Thank you !

-Sko

PS: The cost of a steel Pro-M 92mm MAF calibrated with an 03 Cobra injector curve was around $365.00 for me.

 

[ShelbyGuy]

the tuner uses the data on the spec sheet and the super neato magic tuning software to create a new table of values for the MAF transfer function.

Originally posted by Dana
Since you guys seem to be a little ahead of me on this MAF business, will you please give me a schooling on its function.
I CAN see where a larger MAF will flow more air (by virtue of its larger diameter) at the same voltage or the same air volume at a lower voltage ( I think), but what about the PCM? How does it know that you are doing this or that you have changed the MAF from 90 to 92mm? If you are flowing more air at the same voltage, won't the PCM look at the voltage and apply the original matching fuel tables and therefore run lean?

Thanks,

Dana

 

[trey193]

22 degrees of timing with 20lb's is alot of timing, I bet that thing feels damn good, do you run a mix of race gas with that. I run 25.8 @ 14lb's of boost with a race tune!

 

[skorost]

Originally posted by trey193
22 degrees of timing with 20lb's is alot of timing, I bet that thing feels damn good, do you run a mix of race gas with that. I run 25.8 @ 14lb's of boost with a race tune!

I had 2 choices... back off the timing or get a bigger MAF and I never go with the alternative that makes LESS power lol ... It feels very good and by Thursday I'll have new dyno numbers that hopefully beat my 544 rwtq numbers from my previous tune. I have 94 Octane available to me 1 block away from home. I may drop a degree or two when the nitrous wetshot goes in ...

Tuners ? Tuners ? Beuler ? Anyone ?

 

[Dana]

Ok, so this is not just a plug and play install.
You have to recalibrate the PCM to the new MAF.
Can this be done on a chip also, say the Diablo? Or only the PCM?

OK, I get it now.

Thanks,
Dana

 

[skorost]

Originally posted by Dana
Ok, so this is not just a plug and play install.
You have to recalibrate the PCM to the new MAF.
Can this be done on a chip also, say the Diablo? Or only the PCM?

OK, I get it now.

Thanks,
Dana

Yes... you can do it both ways. I personally am just having the chip's program adjusted.

 

[94SHO]

Originally posted by bassin247
holy boobies, I mean do you think you can flow enough air through that filter?

Yea thats exactly what i was thinking...Post some more pics of that:-D Damn that is one hot filter!

 

[skorost]

Originally posted by 94SHO
Yea thats exactly what i was thinking...Post some more pics of that:-D Damn that is one hot filter!

Maybe I'll bring her out to see you Toledo speed racer... lol... my cousin is big in the Cougar scene out there.