987 Airbox-Worth it?

[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.

[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.

[Nitro V8]

Sorry double post

[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.

[The Radium King]

hey man, i can get you dyno results. my rate is $125 per hour and the car is $500 per day. not sure what the actual dyno cost is, but i'll bill you the actual cost plus 10% markup. the clock starts when i leave the house and stops when i am back home. and i live a LONG way from the nearest dyno.

listen, none of us are selling anything. if you want testing then ask a vendor and don't complain about the cost of their product afterwards. instead of asking a bunch of home diyers to spend time and money to prove info that they are sharing out of the goodness of their heart, how about you take the time and spend the money to try out the mod and see if you like it? seems a lot more fair to me. hey, we already did 90% of the work for you at our own expense.

[maytag]

Originally Posted by The Radium King

hey man, i can get you dyno results. my rate is $125 per hour and the car is $500 per day. not sure what the actual dyno cost is, but i'll bill you the actual cost plus 10% markup. the clock starts when i leave the house and stops when i am back home. and i live a LONG way from the nearest dyno.



listen, none of us are selling anything. if you want testing then ask a vendor and don't complain about the cost of their product afterwards. instead of asking a bunch of home diyers to spend time and money to prove info that they are sharing out of the goodness of their heart, how about you take the time and spend the money to try out the mod and see if you like it? seems a lot more fair to me. hey, we already did 90% of the work for you at our own expense.

A.
Freaking.
Men.

Sent from my SM-G970U using Tapatalk

[edc]

No 987 airbox on my first Boxster but here's some mods with Dyno runs
Tuned/modified 2000 Boxster S

[Cunningr]

Originally Posted by edc

No 987 airbox on my first Boxster but here's some mods with Dyno runs
Tuned/modified 2000 Boxster S

Thanks for sharing that was very interesting. Is the 266 hp at the rear wheels?

[Robert986]

I´m "blueprinting" my upcoming breathing mods right now. Plan on 987 airbox, 987 MAF-housing with 986-sensor, 74mm throttle, 997 Plenum and maybe, if I feel lucky I go all the way and swap in the 996 intake. This + the whole exhaust part.

I have read so much on the subject the last week that I´m actually dreaming about it at night ;-)

I still have two issues I haven´t managed to figure out, so if someone would be able to chime in It would be great.
1) I take it the 74mm throttle seems ok, or even the 76, but what about the 82mm? Would it be beneficial or is it just too big for the 3.2? I understand a 82 throttle from a Cayenne V8 would work and be cheaper than a GT3.
2) I take it that the 987 MAF-housing is too big for the ECU to adapt and a flash is needed, I do plan on a custom mapping by a good tuner however how bad is it with the 987 MAF-housing? Will the Engine run? Will I be able to drive to the tuner with the original tune? Or will I need to take the car on a trailer?

[blue62]

Originally Posted by Robert986

I´m "blueprinting" my upcoming breathing mods right now. Plan on 987 airbox, 987 MAF-housing with 986-sensor, 74mm throttle, 997 Plenum and maybe, if I feel lucky I go all the way and swap in the 996 intake. This + the whole exhaust part.

I have read so much on the subject the last week that I´m actually dreaming about it at night ;-)

I still have two issues I haven´t managed to figure out, so if someone would be able to chime in It would be great.
1) I take it the 74mm throttle seems ok, or even the 76, but what about the 82mm? Would it be beneficial or is it just too big for the 3.2? I understand a 82 throttle from a Cayenne V8 would work and be cheaper than a GT3.
2) I take it that the 987 MAF-housing is too big for the ECU to adapt and a flash is needed, I do plan on a custom mapping by a good tuner however how bad is it with the 987 MAF-housing? Will the Engine run? Will I be able to drive to the tuner with the original tune? Or will I need to take the car on a trailer?

I know a number of people have done this mod, but two things that I never see mentioned is the affect on ignition timing and exhaust temps.
To much ignition advance and or to high exhaust temps are not good.
Might be interesting to take some base line readings before the mod. So you can monitor after

[The Radium King]

Originally Posted by Robert986

1) I take it the 74mm throttle seems ok, or even the 76, but what about the 82mm? Would it be beneficial or is it just too big for the 3.2? I understand a 82 throttle from a Cayenne V8 would work and be cheaper than a GT3.
2) I take it that the 987 MAF-housing is too big for the ECU to adapt and a flash is needed, I do plan on a custom mapping by a good tuner however how bad is it with the 987 MAF-housing? Will the Engine run? Will I be able to drive to the tuner with the original tune? Or will I need to take the car on a trailer?

1) you'll have to decide if the larger tb is giving you a performance increase OR a pseudo-performance increase via what is for all intents and purposes remapped throttle performance. so, think of water; you put a 1/2" faucet on a 1" line and it will be a restriction and limit full flow (it will also increase the water pressure - good for cylinder fill in low-rpm situations). however if you put a 2" faucet on a 1" line then full flow will be achieved when the valve is only partially open - no extra power, but full throttle comes on sooner - pseudo-performance increase. i think the 74mm tb brings some top-end power by removing a restriction (to the detriment of low RPM torque) but the 82mm might be too big for any gains just losses.

2) talk w newart; iirc he ran with the larger maf housing prior to pushing the flash on his car and trims slowly increased until he got a cel. realize that more air is moving than the computer can allow for so you will get into a lean condition which is not good in the long term. fine for the drive to the tuner however.

[Robert986]

Thanks TRK, great answers.


Thinking of how to manipulate the sensor value to simulate the smaller MAF-housing.. On the other hand, if I can "limp" to the tuner, that will be good enough.

[The Radium King]

you might be able to put a variable resistor in line with the maf. there was a great video on youtube where some folks did it w a 996. that's pretty much all that a piggyback computer does; use feedback from a wideband o2 to modify the maf readings that the main ecu sees. you can do the same manually.

https://apexi-usa.com/electronics/afc-neo-fuel-management

[dguy535]

TRK-Thanks for jumping in and offering insight. I’m thinking at this point since I don’t have readily available access to a tuner and mapping capability, I’m going to find the BMW housing that will match the 986 diameter (I believe was mentioned as an E39 535i). Once I have the ability to either upload the 996 tune or get my car mapped to match, I can change to the larger housing and tubes from siliconeintake.

TRK-would you be willing to share the correct models for the appropriate housings?

[The Radium King]

i think that info is in the other long intake plenum thread. i got it from *i think* insite who is not around much anymore (who also had some interesting experiences w an apexi unit). i have one in my garage and can pull the part # in the next few days. iirc it wasn't an exact match ID but closer than the 987 unit. also can't recall if it mated to the airbox; still required cutting - i can confirm that as well. kram has a good thread on adapting the 986 housing to the 987 airbox, or i still have mine sitting around someplace that i don't really need anymore.

[The Radium King]

ok, finally got into my garage.

oem unit (sawn off the airbox) is 75 mm ID.

BMW unit is part # 0280217502 and is 72 mm ID. and, while it has a similar style of mating flange as the 987 airbox, it is smaller so an adaptor would be reqd regardless.

[Robert986]

Sorry for my lack of respons, I really appreciate the answers on my question though.
Still haven´t decided on how to proceed with the MAF..

If I´m not totally wrong: People seem to be happy with the 74mm throttle (also IPD is designed to fit with 74), the OEM MAF for the 986s has an inside diameter of 76mm so are there really any reason to go bigger on the MAF? Using a bigger MAF that will need some sort of recalibration will add complexity and I´m afraid it will increase the cost for my tuner. (it´s expensive enough anyway)

Then I look at the Anniversary model, as we all know it runs on a 987 airbox, I just realised that is also uses the 98760612500 MAF. Could that be an option? If I just use the 98760612500, will I then not need to recalibrate the ECU for the oversized MAF?

Sorry for all the questions, I´m such an amateur

[edc]

The MAF is closer to the throttle body on the Anniversary.

[The Radium King]

986 and 987 maf are the same; 987 unit comes w the holder is only difference (holder detachable in 987, fixed to the airbox in 986). 987 holder is larger diameter than 986; 986ae used special tune. sorry if i missed it - what year is your car?

[The Radium King]

also, as you note, the original maf holder and new tb will be same ID so good there; thing is that the tubing you are using to join the two units fits to the OD which is 1/4" or so larger (the thick lip on the tb is 1/8" or so) so that the air compresses from airbox to maf holder, then expands, then compresses at tb again - wasted work. also, a decreasing radius intake system (ie, airbox larger than maf holder larger than throttle body) will tend to accelerate the intake airflow and facilitate cylinder fill for low rpm torque. small gains overall, and not worth the work of modifying the programming on your car when you can just use the original maf housing. i did it for (a) oem look, and (b) i have a pst2 and wanted to run a 996 tune on my car.