CAI Tuning Question?

[awdfun]

I am new the the TBSS scene. I see posts where you need to tune for a cai. If the cai is not changing the diameter of the maf then what is the reason for getting a tune? I was in the subaru scene and tuned several of them myself. We used to up the diameter of the maf housing to help the with the fuel injector scaling. If you are keeping the stock MAF and location on the tbss and just change the pipe from the maf to the throttle body is there really a need for a tune?

[GTPprix]

It changes the diameter of the tubing leading INTO the MAF basically the same thing. It has no idea that you just increased flow x% through a now larger opening at x hz. ;) Changing the filter has no effect on this reading as far as being skewed, its only when you change the actual entrance (or MAF itself) that the ECM no longer has the proper correlary for frequency vs. flow :)

[ADM PERFORMANCE]

When the air filter element is changed it will allow less restriction to the maf sensor causing it to read incorrectly for what GM has specified it to be with the current stock filter.This will cause the fuel trims to go positive,with positive fuel trims you stand a chance of the system to add to much additional fuel at wide open throttle.Also at light loads you do not want positive fuel trims as it will change the throttle response considerably.

You can change the pipe(we have them available ) and add a 90 degree silicone hose elbow that will flow slightly better than stock,It will also remove the air resonator.But the serious problem exists at the actual filter which is 3.5 inch outlet and the maf is 4".This is a restriction and does need to be changed for optimum results.

There are many air intake systems available for the trailblazer ss.

[PEDRO]

good responses from 2 good vendors!!

[Silver06SS]

When the air filter element is changed it will allow less restriction to the maf sensor causing it to read incorrectly for what GM has specified it to be with the current stock filter.This will cause the fuel trims to go positive,with positive fuel trims you stand a chance of the system to add to much additional fuel at wide open throttle.Also at light loads you do not want positive fuel trims as it will change the throttle response considerably.


So why is there not a "lean" problem with a replacement K&N Filter also? If this is the case, ANY filter that is less restrictive than stock will cause the TBSS to be lean. The MAF is only reading air velocity and sending the signal to the ecm which is reading the ait to determine the density of the air and the correct fueling, isn't it? I've never come across any GM "LS1" truck(not LS2 though) running lean because of a K&N fipk. It does lean it out some, since the truck is running rich from the factory, but doesn't cause a lean condition.

Unless the TBSS is already "tuned" for the stock "cai" and any other cai will lean it out further. This sounds plausible, but I'd still think that there'd be plenty of fuel being dumped to compensate.
The lean condition was said to have been documented on the dyno, but was this on only 1 TBSS or all of them?

Of course I'm no expert and I think this is my first post, but I came from an 01 and 02 GMC 5.3L and tuned them myself with HPTuners.

Anyways, hello to all!

[GTPprix]

Argh here we go again lol REPLACEMENT filters DO NOT change the inlet size to the MAF, therefore other than oiling the MAF up they have little effect on fuel skewing. A CAI worth a damn on the other hand will since the biggest restriction in the system is at that point.

The MAF only knows how much air will pass through the smaller opening at X Hz.. change the opening size and the tables are no longer correct resulting in a nice fat condition at the bottom and about 14.2:1 at the top of a gear.

What I think you'll find the big companies like K&N and Volant are going to do is just leave that neck down there but delete all the silencers and ribbed tubing. It'll probably help a little but if your going to do it, why not do it right? ;)

[Silver06SS]

Argh here we go again lol REPLACEMENT filters DO NOT change the inlet size to the MAF,

Not to be a pain, but we're still not changing the size of the MAF, so there is still only X amount that can flow through the MAF, regardless of the inlet tube size, right? Or are you saying the MAF isn't tuned for the size of the MAF, but the inlet tubing? To me that wouldn't be right. I mean, why have the bigger MAF in the first place?

Please excuse my questions. I'm not trying to argue, just understand more about the LS2. I haven't owned a GM vehicle in two years.

Thanks
Paul

[Fishhunter911]

Not to be a pain, but we're still not changing the size of the MAF, so there is still only X amount that can flow through the MAF, regardless of the inlet tube size, right? Or are you saying the MAF isn't tuned for the size of the MAF, but the inlet tubing? To me that wouldn't be right. I mean, why have the bigger MAF in the first place?

Please excuse my questions. I'm not trying to argue, just understand more about the LS2. I haven't owned a GM vehicle in two years.

Thanks
Paul

There is a HUGE neck down right before the MAF. The original tune is diesigned to handle the flow throught that. When youopen up the neck down, you get a lot more flow. Which throws off the A/F ratio. Trust me when I say, you need to get it tuned when yo get rid of the neck down. If yo replace EVERYTHING except the neck down, no tune needed, but also you do not get much more out of it.

[GTPprix]

Not to be a pain, but we're still not changing the size of the MAF, so there is still only X amount that can flow through the MAF, regardless of the inlet tube size, right? Or are you saying the MAF isn't tuned for the size of the MAF, but the inlet tubing? To me that wouldn't be right. I mean, why have the bigger MAF in the first place?

Please excuse my questions. I'm not trying to argue, just understand more about the LS2. I haven't owned a GM vehicle in two years.

Thanks
Paul


Ok I'll put it as simply as I can the MAF table in the TBSS is setup to read the amount of air that CAN pass through the neck down at a given frequncy output. Remove the neck down and that relationship changes skewing the fueling. These systems are calibrated as just that an assembly/system not independantly since the intake tract causes turbulance that must be corrected for.