Airaid or JLT CAI

[Seer]

Can someone enlighten me as to what's supposed to be wrong with the MAF readings from the JLT intake? I have one and def don't want problems...

I'm no tuner by any means and have no idea what I'm looking at, but in my datalogs that I've done, the MAF frequency looks smooth at idle, part throttle, and WOT and basically goes up or down with rpms and if I'm giving it gas or not as it's flowing more air. No messed up signal, spikes, or anything like that.

it can be tuned around for the most part.

For instance some of the issues the JLT big air has been documented to do on the GT500's and PD blown 5.0s, it will sometimes trip a DTC for system going too lean due to a faulty maf transfer.

 

[iceguyb14]

it can be tuned around for the most part.

For instance some of the issues the JLT big air has been documented to do on the GT500's and PD blown 5.0s, it will sometimes trip a DTC for system going too lean due to a faulty maf transfer.

Oh ok. What about for the 5.0s with just bolt ons? And yeah I saw it can be tuned around, but if it messed with the signal a ton, wouldn't that show up in datalogs of the MAF frequency? Or would the tune fix it?

 

[kdanner]

Oh ok. What about for the 5.0s with just bolt ons? And yeah I saw it can be tuned around, but if it messed with the signal a ton, wouldn't that show up in datalogs of the MAF frequency? Or would the tune fix it?

It absolutely shows in the logs. The signal is quite erratic compared to others. I am not the only one who has put up graphs of this in the past. Also you can do things like log idle RPM and see how erratic it is compared to stock.

 

[Seer]

Oh ok. What about for the 5.0s with just bolt ons? And yeah I saw it can be tuned around, but if it messed with the signal a ton, wouldn't that show up in datalogs of the MAF frequency? Or would the tune fix it?

Depends on the skill level of the tuner. If all they are doing is just taking the transfer values and plugging them in, and if the CAI is deficient, then ya you would see some irregularities. Tuning around it though is never a good thing, because then the vehicle isnt running 100%.

The transfer is basically the product of an equation that changes what the MAF sensor should be expecting in voltage and translates that into airflow.

Since you are enlarging the MAF housing most of the time when switching CAIs a new transfer value has to be inputted into the transfer table so the sensor knows what voltage equals what air flow.

This is my best laymen description.

If the transfer is off or if the CAI produces uncalculatable (if thats even a word) values, the final voltage/airflow reading will be off and the car will either give too much or not enough fueling.

For the copperhead pcm equipped vehicles, the wideband o2's in the rear can correct this to a point, but remember you have a MAF reading faulty up front, then the o2's reading properly in the rear. So it then becomes a continuous cycle, then a code gets tripped in extreme examples, or you will fine hesitation, surging etc at idle, wot, cruising.

Some of the problems with using SCT as a logger, is it is not high speed logging device to catch some of these values in a finite resolution, like say a Cardaq is.

You also have high and low injector slope values as well that can play a role in this.

 

[iceguyb14]

It absolutely shows in the logs. The signal is quite erratic compared to others. I am not the only one who has put up graphs of this in the past. Also you can do things like log idle RPM and see how erratic it is compared to stock.

Hmm I don't get how it's erratic though. Looking through my logs, I let it idle for about a minute then drive the car and it sits at 1.22 the entire time it idles until I start to drive...

Depends on the skill level of the tuner. If all they are doing is just taking the transfer values and plugging them in, and if the CAI is deficient, then ya you would see some irregularities. Tuning around it though is never a good thing, because then the vehicle isnt running 100%.

The transfer is basically the product of an equation that changes what the MAF sensor should be expecting in voltage and translates that into airflow.

Since you are enlarging the MAF housing most of the time when switching CAIs a new transfer value has to be inputted into the transfer table so the sensor knows what voltage equals what air flow.

This is my best laymen description.

If the transfer is off or if the CAI produces uncalculatable (if thats even a word) values, the final voltage/airflow reading will be off and the car will either give too much or not enough fueling.

For the copperhead pcm equipped vehicles, the wideband o2's in the rear can correct this to a point, but remember you have a MAF reading faulty up front, then the o2's reading properly in the rear. So it then becomes a continuous cycle, then a code gets tripped in extreme examples, or you will fine hesitation, surging etc at idle, wot, cruising.

Some of the problems with using SCT as a logger, is it is not high speed logging device to catch some of these values in a finite resolution, like say a Cardaq is.

You also have high and low injector slope values as well that can play a role in this.

Thanks for the explanation. And yeah I know the SCT is'nt the most high speed logging device, but it doesn't do a bad job from what I've heard. But either way I guess since my car doesn't really have issues with surging or hesitating and drives good, I'll be fine.

 

[Seer]

Hmm I don't get how it's erratic though. Looking through my logs, I let it idle for about a minute then drive the car and it sits at 1.22 the entire time it idles until I start to drive...



Thanks for the explanation. And yeah I know the SCT is'nt the most high speed logging device, but it doesn't do a bad job from what I've heard. But either way I guess since my car doesn't really have issues with surging or hesitating and drives good, I'll be fine.

or it was tuned around.

 

[iceguyb14]

or it was tuned around.

Can you tune around it so it doesn't have an erratic signal? I figured tuning around it would mean a slightly erratic signal wouldn't affect things.

 

[Seer]

Can you tune around it so it doesn't have an erratic signal? I figured tuning around it would mean a slightly erratic signal wouldn't affect things.

can i see your logs?

 

[iceguyb14]

can i see your logs?

sure idc. how do i send them to you? lol

 

[Seer]

sure idc. how do i send them to you? lol

you have my email address in a pm

 

[iceguyb14]

you have my email address in a pm

sent

 

[Nasty GT]

you have my email address in a pm

Sent you a PM as well Seer.

Faron