987 Airbox-Worth it?

[dguy535]

Those that have done the 987 airbox, with 74mm TB and either IPD or 997 plenum, what were the measured gains from the airbox on it's own? I have the TB and plenum that I will be installing, and trying to decide if the airbox is worth it. Seems a LOT of work to manage the MAF issues as well as tuning (I don't have PIWIS to download a tune on my own) especially if the gains are nominal. Would love to hear some feedback either way.

[rfuerst911sc]

The dyno graphs I have seen including my own the average increase just for the air box is 5 hp .

[BYprodriver]

Originally Posted by rfuerst911sc

The dyno graphs I have seen including my own the average increase just for the air box is 5 hp .

I assume that was for your stock engine ??

[rfuerst911sc]

Have seen the 5 hp change on stock and modified engines.

[dguy535]

Originally Posted by rfuerst911sc

Have seen the 5 hp change on stock and modified engines.

What MAF setup are these running? My concern is this turns into a never ending rabbit hole for tuning and what not.

If I swap the TB and plenum, but maintain the 986 AB, my understanding is I CAN use the existing mapping and maintain drivability with increased response. I don’t want to get into wide band O2 systems and what not to tune around a new problem with increased MAF diameter that I create.

[BYprodriver]

Originally Posted by dguy535

Those that have done the 987 airbox, with 74mm TB and either IPD or 997 plenum, what were the measured gains from the airbox on it's own? I have the TB and plenum that I will be installing, and trying to decide if the airbox is worth it. Seems a LOT of work to manage the MAF issues as well as tuning (I don't have PIWIS to download a tune on my own) especially if the gains are nominal. Would love to hear some feedback either way.

I would say it may be the best mod to do other than exhaust. Install is not easy it's best to remove driver side intake runners.

[NewArt]

I have a video on my YouTube channel where I do this mod. It may be of help.

[maytag]

Originally Posted by dguy535

I don’t want to get into wide band O2 systems and what not to tune around a new problem with increased MAF diameter that I create.

I contacted VRTuning (VividRacing) and they sent me a MAP file and the hardware to flash it, based on the mods I told them about. They did a pretty good job. It might be just a LITTLE bit rich, but I can attribute some of that to my 3500' elevation. haha

plan on $800-ish for the hardware and flash-file.

[particlewave]

As long as you don’t exceed 120% of the original air volume flowing over the MAF, the DME can adapt, no remapping necessary.

A rudimentary volume calculation can be achieved by using the diameter of the original MAF tube vs new and inputting the numbers into the formula for area of a circle. It’s not perfect, but will give you a rough idea. You can then check your fuel ratio to confirm whether or not it has adapted.

[blue62]

Originally Posted by particlewave

As long as you don’t exceed 120% of the original air volume flowing over the MAF, the DME can adapt, no remapping necessary.

A rudimentary volume calculation can be achieved by using the diameter of the original MAF tube vs new and inputting the numbers into the formula for area of a circle. It’s not perfect, but will give you a rough idea. You can then check your fuel ratio to confirm whether or not it has adapted.

Hey Particlewave,
Do you mind if I ask where you get the 120% figure from?
I am always trying to learn more about the capabilities of modern day engine management systems.
Thanks

[particlewave]

Don’t recall...I’ll try to find it, but it was reputable.

[particlewave]

Check this thread (pg2): 987 v 986 Air box

It seems it may be adaptable up to a 25% increase (125% of original). Good info there, but I’ve seen it repeated by other reputable sources or I wouldn’t have committed it to memory.

[dguy535]

Originally Posted by BYprodriver

I would say it may be the best mod to do other than exhaust. Install is not easy it's best to remove driver side intake runners.

You’ve built some pretty significant motors for these. Did you use a 986 MAF or the larger diameter 987 one? If it’s worth the additional work for tuning, It seems like a worthwhile mod. Just not sure how to go about it.

[maytag]

Originally Posted by dguy535

.... It seems like a worthwhile mod. Just not sure how to go about it.

Did you follow the link particlewave provided below?

There are many, MANY write ups with excellent instructions on this forum. Hit the search bar, you'll be amazed .

Sent from my SM-G970U using Tapatalk

[dguy535]

I've researched this ad nauseum, and have come to the conclusion that there are a number of butt dynos who have registered gains after tuning, but limited info with regard to the larger MAF from a 987 being used. I've read here and seen videos that suggest that additional tuning with either a 996 tune or VRTuning type software is necessary to make the larger MAF work. As I mentioned before, I don't have access to either of those at the moment, and am not convinced the improvements are worth the cost and difficulty to install. Would love to see some hard data that supports it, or get more feedback from someone who has installed the 987 MAF on what the best course is. I can definitely recognize that the 987 AB is an worthwhile improvement as even Porsche used it on the anniversary edition. I need to make a decision as to how I want to invest in the supporting HW/SW to make it work. My thoughts at the moment, suggest using the 987 AB with tubing to allow for the 986 MAF. Unfortunately, a lot of the threads on this subject are older, and folks like The Radium King who've done a lot of research aren't as active. I was hoping to locate some info that would support either method with good dyno info.

[BYprodriver]

Originally Posted by dguy535

You’ve built some pretty significant motors for these. Did you use a 986 MAF or the larger diameter 987 one? If it’s worth the additional work for tuning, It seems like a worthwhile mod. Just not sure how to go about it.

As listed in my signature, I have a 987 airfilter housing & MAF that has the the same diameter as a 996. This requires reprograming the DME for the larger diameter MAF. This really woke up my 3.6 liter rebuild. On the test drive the 1st time I floored it The induction noise scared me.

[blue62]

Originally Posted by rfuerst911sc

The dyno graphs I have seen including my own the average increase just for the air box is 5 hp .

If you have access to dyno graphs could you tell us where in the RPM range the 5 hp gain is?
More importantly what are the torque gains? and where?
Are these gains in the low to mid RPM range? So they would be useable on the street?
Or more on the high end of RPM so more applicable to the track?
Thanks in advance

[blue62]

Originally Posted by particlewave

Check this thread (pg2): 987 v 986 Air box

It seems it may be adaptable up to a 25% increase (125% of original). Good info there, but I’ve seen it repeated by other reputable sources or I wouldn’t have committed it to memory.

Thanks
I have read that thread in the past. Ended up re-read the entire thread again.
Don't know if I should thank you for that or not Some good experimenting going on there.

[rfuerst911sc]

Originally Posted by blue62

If you have access to dyno graphs could you tell us where in the RPM range the 5 hp gain is?
More importantly what are the torque gains? and where?
Are these gains in the low to mid RPM range? So they would be useable on the street?
Or more on the high end of RPM so more applicable to the track?
Thanks in advance

Sorry those graphs were over a year ago . I don't remember the specifics but I know the guy's at Jake Raby's shop and they have told me many times they see an honest 5 hp increase from the air box swap .

[edc]

You can get 5+ bhp without the airbox and just doing a 996 plenum and 74mm throttle body. You'll see the gains from approx 3.5k onwards.