cai
 

If any of you guys could help i would appreciate it. I have some of Bill's tunes and want to put on aem cai or use jackandjanets' gotts intake instructions. does a cai really make that much difference. and if i did either of them would i need new tunes. thanks guys





thank a vet, you may never know what they have done for you

I believe you would have to get the tunes adjusted. Adding a CAI or Gotts mod can make a difference in the performance. The best way to take advantage of one is to have a tune telling the truck what to do with the extra air. Since your tunes were for the stock intake, you would probably have to get your tunes adjusted. I'm not sure what all has to be changed, but I think the Air to Fuel ratio has to be corrected.

I just bought an AEM intake and I'll be installing it next week. I don't have custom tunes yet, but I'm about to buy them. I know the canned tunes were written for a stock intake, which provides less air flow. By adding the CAI, it increases the amount of air the engine gets, and the fuel amount stays the same, causing a leaner condition. I would think it would be same for a custom tune written for a stock intake.

thanks, appreciate. you should check out the aem thread on f150 online. its really indepth

Here is a simple solution!
Do the custom dwv/gott's mod and a aem drop in!
Approx $45 and doesn't hurt anything, no additional tweeking required.

Lars

I'm going to insert a small correction here. Installing the "Gotts" style intake will NOT require a retune. Yes, we think you get extra air with it, but because the environment around the MAF sensor is not disturbed, the sensor will see the extra air properly and the PCM will be able to adjust the A/F ratio accordingly. This is NOT true of a commercial CAI that alters the MAF sensor environment though. That would require a retune, because the sensor does not really "see" the extra air.

Does the "Gotts" intake make that much difference? Not really. I don't seem to be able to "feel" the extra 7-8 HP it's supposed to give me. But, the engine runs very smoothly, and, it's even possible I'm getting slightly better gas mileage.

- Jack

I stand corrected. I had a feeling I would learn a few things on this forum. Does the MAF sensor adjust because the filter is still after the MAF sensor? And it doesn't adjust on a CAI because the filter is before the MAF sensor?

I believe it's more than that, but I haven't studied any of the commercial CAIs beyond looking at pictures of them installed. It appears to me that the whole intake system is replaced up to the throttle body. And, if the sensor is "calibrated" for a specific cross section and air flow characteristic, it's going to "see" something different there. I think to really work properly without a custom tune, the sensor would have to be redesigned a bit for the new environment. (I think it's essentially a heated resistance wire that's cooled by airflow, and that's a pretty simple analogue device, if I'm right).

In the stock setup, the sensor is AFTER the filter, above and behind it on the driver's side, in my truck. All the changes done to the intake in the "Gotts" style mod are way before that location, and are limited to allowing extra air in. By the time airflow reaches the sensor, the flow pattern is the same as always (more or less), but potentially, there's more of it. In a commercial setup, everything is different all the way to the throttle body. The simple sensor can't really account for all the differences.

What I've just said is mostly based on discussions with Bill on this system.

- Jack

Good points Jack!

Another thing Bill looks at when writing tunes for cai's is that each mfgr places them "generally" in the same area. But when the cai went through r+d the mfg looked for the optimum placement of the maf in it's cai. From what I understand of looking for their specs the placement may differ an inch or two or three from which ever mfg you chose. Thus the flow of air may be different at that area. Also alot of mfgs test at WOT. Find a cai mfg that tests all the way through the rpms and for DDs not for racing.

Lars

Thanks for adding to this Lars. I thought perhaps I'd over simplified.

- Jack

Here's another one I just was reminded about.
Mfgs also use different size intake tubes.
So if mfg a tube is the same size as mfg b tube no adjustments should be needed. But if mfg c has a larger tube than mfg a then the tune may need tweeking. The same would go for the reverse, if mfg c tube and down sizing to mfg a tube.

Lars