Would it be necessary to set up a MAF Clamp if your runing the MAF sensor on the intake pipe of the turbo? Is setting up a MAF Clamp only necessary if your runing a blow thru set up were the MAF sensor is located on the charged pipe? Or do you have to set up a MAF Clamp either way? From my understanding of the purpose of the MAF Clamp, I dont see how it would be necessary to set one up if the MAF sensor is on the intake pipe since it never sees boost.

 

You'll most likely have to clamp it either way. It's not the pressure that it sees, it's the greater volume of air. If the diameter of the MAF tube is changed, you'll also have to modify the MAF voltage table to compensate. In my case, I have a draw-thru MAF with a 5% smaller MAF tube and if I don't clamp the MAF, I get a recurring P0101 CEL for "MAF out of range".

 

well i think my intake pipe is still the factory inner diameter tube. I was just asking cause if its not necessary then i wasnt going to waist my time trying to do this.

 

imho its 100% necessary for a solid running turbo tc (or supercharged for that matter) without having a check engine light on all the time. If you understand how to do it then i suggest doing it, if your lazy you could maybe get by using a maf map from another tune (base map), if its close enough it will do. good luck

 

You could always try it without clamps and add them later if you get MAF codes. I found out the hard way that AEM's instructions for the MAF map don't work very well. My first maf map was clamped way too low when I followed their instructions. I've since had to raise all of my clamps between 0-4000rpm. The 4000-6500rpm clamps were okay.

ElevationTC posted a FIC base tune from AEM a few weeks back. You might want to try that MAF map. It looked decent.

 

alright well thanks for yas inputs on this. Im not lazzy i just didnt want to alter the map if it wasnt necessary. So here's another question for ya guys. If i hook up the F/IC to my car as stock with stock injectors, would i just set the fuel map, ignition, and 02 map tables to 0 since i wouldnt need to change any factory settings? Also would it matter what i set the injector response to if im not altering the fuel maps? I need to know this so i can log the MAF to set my MAF Clamp.

 

would want to go to set up menu and set maf to percent and 02 to percent, leave all the maps zero and i think that will work. havnt had to do it lately so yeah.

 

cool. ima give this a try here in a little while. Thanks for your help. Ill post up if this works or fails.

 

Crush is correct and I wouldn't worry about the response time since it makes little difference. 486us should be close enough for what you're doing. Logging your MAF is a great idea. I've seen 2 very different TC maf maps from AEM now and both have serious flaws, IMO. The first jumps from 0-2.19V which is far from ideal and the second doesn't start clamping until 3.6V which will most likely throw a P0101 CEL. Of course there are infinite variables from setup to setup and those maps may work for some.

 

everyone that iv come accross around h-town already has installed their kit when they come to me so i dont get much of an opertunity to do stuff like this, so i wasnt sure.

 

I've got data logs from an 09 completely stock on the F/IC. I logged MAF readings and pretty soon I'm going to do a wideband data log for other fine tuning purposes. But, yes, set them to percent and you are golden. Leave them at voltage and be prepared for limp home mode.

 

I had a little trouble but got it all working. Thanks for the help guys. I set the IRT to 486us and set all my maps to zero with the MAF map to percent. Did 6 runs worth of data logging to make sure i get values as close as possible. I finally got done filling out my MAF map with the Clamp and tested it out. works perfect so far. And yea it was off by a quite a bit from the base MAF map i used to use. Now I just need to get my turbo back from repairs and redo my fuel maps for boost.

 

Just so you know.. The maf table is used to alter MAF signals that would be inaccurate due to wrong sized piping.. If you change maf to percent and use small alercations to it, and set max voltage clamp to a set voltage it will never pass this!

If your Pull through maf, and in correct size piping. IMO i would leave the maf map at 0 percent and just set the max voltage clamp!

 

SO many people are mislead by what the maf table is accually for! hopefully you get it!

 

I think you misunderstood what i said. I only set the MAF Table to zero in percent mode only while i was doing the logs to see what the MAF voltage was. Then i set the MAF map back to voltage mode and filled out the table with the Maf Clamp. I didnt leave it in percent mode. Im not confused on the purpose of doing this. I understand what it does.

 

I can only speak from my own limited experience but setting only the max MAF voltage clamp results in a persistent and recurring P0101 CEL on my 08 XB. It's not caused by the 4% smaller diameter MAF pipe either. I have to start clamping at 2.5V to avoid a CEL. A few days ago I tried the map you gave me and got a 101 on the first drive. I then lowered the starting clamp to 3V and still got a 101. I suspect that this behavior is common for the 07+ ECU's but it could be XB2 specific.

FWIW, I started getting the P0101 code the same day I installed larger (440cc) injectors without changing anything else (IHE-only). Prior to installing the new injectors I had been CEL-free for about a year with the same IHE mods. Obviously my 08 ECU didn't like the MAF readings it was seeing compared to the new fuel trims required by the larger injectors.

 

What was voltage on your XB before turbo?

This is the info that you need! Also what are your fuel trims?

Let me give you this example! Yesterday i tuned a car using a OEM air box. I changed maf to percent and set all zero's. I went into aem fic settings and put max voltage clamp to 4.40.

This was a 07+ I tuned the car and i was amazed at how smooth it was. Idle stayed pretty much between 14.6-14.8 I was able to tune the afr to a complete flat line during data logs.

 

Pre-turbo using the oem airbox, my maf V ranged from 1V at idle to 3.8V max. Post-turbo maf V ranges from 1V to 4.3V max. When I raised the 0-2450rpm clamps from 2.5V to 3V I got a P0101 on the first test drive, cleared it and it came right back. If I start clamping at 2.5V and gradually increase the clamps to 4V max, no CEL. Compared to my oem logs, all of my clamps are at least 10% higher than my logged readings.

Using the FIC to correct for the larger injectors my LTFT stays within 10% +/- and averages 0%. Pre-FIC LTFT with the 440s was -25% max and -15% avg.

I didn't mean to say that clamping only the max maf voltage wouldn't work, just that it doesn't work in my case. I suspected that the same might apply to all 07+ ECUs but apparently it doesn't. I wish I could simply clamp my maf max V. It would be a lot easier and I wouldn't have to worry about any of my clamps being set too low or too high. For whatever reason it just doesn't work for me. FYI.

 

I run a Fujita MAF adapter and have never threw any codes at 6PSI. I am uping the boost to 14PSI and tuning with the FIC. Is it only necessary if you throw codes?

 

If your maf tube is the same ID as oem, your maf voltage table should be 1:1 (2.0V=2.0V) or left in percent mode (all zeros). If you're not getting any MAF codes, I see no reason to clamp it.

It's worth noting that excessive fuel trims can also contribute to MAF CELs. If the ECU is trimming a lot of fuel but the maf is reading normally, you can get a P0101 because the ECU thinks the maf is reading too much air for the amount of fuel that the ecu thinks it is injecting.