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Yes...it can be done
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Discussion Starter · #1 ·
I pegged it @ 11 psi. On the second dyno pass at 6000 RPM, the A/F shot up from below 10:1 to about 12:1 (wish I had a scanner for the dyno sheet).

Can any of the other Kenne Bell 03's verify this? If you don't have data logging software it can be done by backprobing the first two wires on the MAF wiring harness. Use a digital multimeter and some sewing needles. The supply voltage to the MAF is 12V, but the EEC will clip at 4.91V. Any reading over 4.91V will not translate to the EEC.

I wonder if they missed this in the KB write up in 5.0 magazine? Could there be even MORE potenial above 6000 RPM? :)
 

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I've been wondering how this has been dealt with. Nobody seems to have brought it up yet.

In this thread mjchip said

"The maximum rwhp that the stock MAF will support before saturation is approximately 500."

So what are you 600 RWHP guys doing?
 

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Yes...it can be done
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Discussion Starter · #3 · (Edited)
According to my results, mjchip is correct. So I guess I have three choices:

1. Figure out the input impedance on the EEC, spend $5 at Radio Shack, build a voltage divider circuit to prevent EEC clipping, and rework the MAF transfer functions.
OR
2. Spend $200-$300 on a different MAF for my combo, and rework the MAF transfer functions.
OR
3. Say fug it, I don't need to optimize the car above the point where the MAF pegs. Where is that KB flip chip?

Either way, I would like to do my little backprobing trick when I get back in town (4/12). I want to see the voltage that the MAF is putting out vs. RPM.

I will report my findings, unless somebody wants to beat me to it. Pleeeease!!!
 

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I tested the stock mass air and the Pro m 95mm, and had no difference in hp . the stock unit is close to max. but works fine .
the pro m 95mm did nothing to inprove the pref, or voltage from the meter,
Again all in the combo.
seek and yee shall find the combo, or call nitro
 

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Yes...it can be done
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Discussion Starter · #5 ·
Tough to argue with the man who runs 9's! :D

Thanks Pete. No pegging for you, eh? Mine pegged hard at 6k RPM. I want to check it again with a voltmeter when I get back. If it pegs again, I'll have to do something to correct it.

Maybe I could just take the KB off! :p
 

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Sounds like you may want to put some voltage in the fuel pumps
the pro m 95 did'ent help mine. Well it did a verry little droped the a/f from 12.2 to 12.1 , I dont think that was worth it . How is your air intake, filter ? , there is no bend in the set up ? peace
nitro
 

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Yes...it can be done
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Discussion Starter · #7 ·
Yep, gotta bend. Densecharger CAI. Hmmm...

I gotta K&N I could throw in the stock airbox to test. Ya thinking the bend is causing extra turbulence across the sensor, Pete?
 

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Snake Charmer
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I was under the impression weather or not a MAF can peg is dependant on many factors such as temp/ baro press, engine load etc. Are you pegging stock maf in all gears at 6000rpm or just 6th?
 

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The Ubiquitous Jimmy V.
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Pete, Pro M meter for our cars is a 92 not a 95..Atleast that's what Pro M told me..
 

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Discussion Starter · #10 ·
Shadowgray03 said:
I was under the impression weather or not a MAF can peg is dependant on many factors such as temp/ baro press, engine load etc. Are you pegging stock maf in all gears at 6000rpm or just 6th?
I pegged it in fourth gear on the dyno. I'm going to test it again on the street, and the dyno when I get back to STL.
 

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Snake Charmer
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I suppose if we cant find a MAF to give proper readings at WOT due to pegging then we will simply have to make sure the open loop tables are properly done. Its obvious that the stock MAF can feed the HP, although it may be a slight bottle neck, its just that the EEC isnt aware of actual Air flow, but in the case of going WOT how important is it really? In open loop WOT situations, arent the O2's out of the picture anyway and the A/Fs are simply pulled from a table as opposed to being actually micromanaged by the EEC as they would be in closed loop normal driving conditions?
 

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since it lets you attach files here, I am attaching the data log from the dyno run. The car hit 1023 counts at 5900RPM's (or 83mph) on the dyno. 1023 is the max counts for the meter, so it's basically pegging.

When the air meter pegs, that's bad. The EEC is a control system, and when you stop getting accurate data it's no longer on control. The MAF is probably the most important sensor in the system. Even if you can increase pump voltage to get your air/fuel down, volumetric effeciency is not right. If your VE isn't accurate, the EEC really isn't calculating the true spark and load values. Look at the calculated engine load in the data I attached. Notice after the MAF pegs that it actually is decreasing as the engine RPM's increase.

My suggestion is to get a meter that has a better voltage range. I can't tell you if it will definatly make more power, but IMO letting the EEC have full control is always the best way to go. I'm not saying that the other ways don't work, that's just how I would do it.

Brian
 

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in open loop the EEC is just taking data from the air meter to calculate fuel and spark. You can make fuel table changes, but it would be changing the commanded fuel to a number below where it acually is, which is still giving the computer false information. again, it would work, but IMO I like the eec to have real values and full control. How much of a big deal is it? I'd have to take data on one making 600RWHP both ways before I could form an opinion. Normally when I see a meter peg, I make them change it.

Brian
 

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Snake Charmer
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bjherron said:
My suggestion is to get a meter that has a better voltage range. I can't tell you if it will definatly make more power, but IMO letting the EEC have full control is always the best way to go. I'm not saying that the other ways don't work, that's just how I would do it.

Brian
I totally agree Brian but in the interum I was just curious as to how detrimantal it would be during short burst open loop operation. I guess more testing would be needed. Is the 03 cobra using the fomoco 90mm? Its my understanding that 0-5v is all the EEC understands so what we need to do is find a maf that doesnt have a larger voltage range, but actually flows more air at a given voltage range and then have the EEC flashed/chipped so that it knows that at xx volts its now flowing xxx air.
 

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Yes...it can be done
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Discussion Starter · #15 ·
Hey Brian, I think nitro is on to something. We should try removing the Densecharger CAI and see what happens to the MAF voltage. Removing the bend in the intake could change the MAF readings. :)
 

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Hey 03steve, try the filter 1st, put a 9" or bigger in there , Striaght line. then check it out , It may not drop it super low but I think it will help. Boosting the fuel press. will also help
nitro
 

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Shadowgray03 said:
Its my understanding that 0-5v is all the EEC understands so what we need to do is find a maf that doesnt have a larger voltage range, but actually flows more air at a given voltage range and then have the EEC flashed/chipped so that it knows that at xx volts its now flowing xxx air.
That's how I understand it as well. I've seen guys talking about getting their hands on the GT's MAF since it's 500HP stock.
 

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Yes...it can be done
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Discussion Starter · #18 ·
Thanks Pete!

I'll be installing the boost-a-pump when I get back for the fuel pressure. I'm pretty sure I have something in my box of tricks to replace the Densecharger. I will post what I find!
 

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Yep, a maf will read way above 5V, but the EEC can only take in the first 5V. What I meant was to get a meter that will sample a larger volume of air within the 5V range.

Steve, if you want to do somthing else with the filter, we can do some data logging on the streets.


Brian
 

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Snake Charmer
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bjherron said:
Steve, if you want to do somthing else with the filter, we can do some data logging on the streets.
Brian
What are you guys using to do your data logging?
 
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