987 v 986 Air box

[Brad Roberts]

Pushing it to a server now

[Brad Roberts]

I'm only going to leave it up for an hour or so while I deal with a customer. Blue, download it, I'd like to go over some thoughts with you offline.

[blue2000s]

Originally Posted by Brad Roberts

I'm only going to leave it up for an hour or so while I deal with a customer. Blue, download it, I'd like to go over some thoughts with you offline.

Got it. Nice.

[The Radium King]

It all makes sense. But I wonder if the DME just makes small corrections to one load/speed point on the map at a time or if it tries to smooth the map around the point of correction. The O2 sensor isn't fast enough to relay good data while the engine is dynamically changing, like changing loads or RPM. It needs the engine to be steady for a while to know what the conditions are at the intake relative to the exhaust.

Although, I suppose if they charactorized the lag, maybe they've figured out how to use that data too. Maybe.

i doubt that the dme is sophisticated enough to incorporate the 02 sensor lag into analysis, nor to interpolate the curves. rather, i *think* it tends to apply the stft to 'regions' of the maps - idle/coast, under load, wot, etc.

[Marchie]

This is perhaps one of the most interesting threads I've come across, regarding boxsters.
I'm hoping there is more info on this subject to come. Brad is there any more pictures of the air cleaner box after the modification , as it would be very interesting to see, pretty please . It's nice to see for a change no one ********************ing or telling you guys you have done it wrong or you don't know what your doing, lol.
A DIY for this install would be fantastic , and interesting. Keep up the good work.

[Brad Roberts]

Want to know why shop owners stay off the forums? We get tired of being told we are doing something wrong by an armchair engineer who has owned one Porsche and has only worked on HIS car. I speak with Porsche shop owners world wide on a daily basis (and Boxster owners nationwide) I tell everyone to take in all the information you can, but QUALIFY the person giving out the information (what do they do for a living?)

Luckily.. in the Boxster community, you have a LOT of smart people that solve problems!! other Porsche communities are sometimes lacking

In the picture below, we trim off what is the "muffler" We trimmed this first one back a tad too far, but did not get into the actual airbox. After trimming, you will see this "hole" that leads into the air box (or MAF housing)





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[Brad Roberts]

This how I patched it:



We use a ton of 10/32 allen screws to attach body panels into nut sert plates, so we used two of them here with nylocks on the back to secure a small alum plate we made





Can a plate be fitted 100 different ways? sure.. pick your path. This took 10minutes max.


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[Marchie]

Thanks for the reply Brad, Am still a little confused . We cover that hole, Why ? And what happens with the large cutout we have just made.
I'm definitely no mechanic, just trying to learn how things work so if they make sense to me I can then make a decision to try them or not.
Thanks for the help so far.

[onaFLYer]

Originally Posted by Marchie

Thanks for the reply Brad, Am still a little confused . We cover that hole, Why ? And what happens with the large cutout we have just made.
I'm definitely no mechanic, just trying to learn how things work so if they make sense to me I can then make a decision to try them or not.
Thanks for the help so far.

The hole is open to the engine compartment after removing the back side of the assembly, past the air filter. So you want to cover it so nothing gets sucked directly into the air stream and MAF w/o being filtered first. I have the same looking patch on mine.

If you look at the pic's I posted, the 2nd one shows the portion that was cut off, right behind the tube that comes out from the assembly past the main housing. Hope this helps.

[Brad Roberts]

Thanks Flyer!! I didn't decide to take pics of ours until *after* we had cut the box off

[jaykay]

I am struggling with what the contribution of a software remap is to engine power after one has increased air flow rates (without hurting velocity) through hardware changes. If the 25% value is correct, the stock map will adapt.

I can understand remap benefits for where ignition timing is refined for a given fuel quality (anti knock rating). What other benefits can a remap hope for?

Also wondering what power increases everyone has realized with the 987 box. I would expect its real value would be seen on a 3.4 and 3.6L where you may start to get significant vacum readings (MAP) in the intake system. I would only expect a minimal gain on a 3.2. Perhaps I am wrong...just trying to learn. Will my stock air box be good enough up 290 hp or so? Is MAP data via OBDii good enough to see what is working?

Originally Posted by The Radium King

i've been looking into tuning recently and here is what i think i know:

dme looks at (a) maf signal (amount of air going into the engine) and (b) rpm, to determine how much fuel to deliver via the injectors. this is done using a 3D, 3-axis map (x=rpm, y=quantity of air, z=amount of fuel required). these are the maps that get modified by tuners to increase performance.

dme then looks at exhaust o2 sensors to see how things went during combustion. depending on the amount of oxygen in the exhaust, the dme either adds or removed fuel by lengthening or shortening the injector pulse.

this information is put into a short term fuel trim map (stft) as a % modifier of the primary map.

if the stft stays stable (ie, over about 50 kms of driving) the data is transferred to the long term fuel trim map (ltft). this is your dme 'learning'.

if you find that your ltft is staying at a constant value (ie, +5% due to intake modifications) tuners can go to the maf calibration map and calibrate it so that your ltft zeros out. you may wish to do this to make room for other modifications, as max ltft is 25%.

so, if you put a 3.5" diameter maf housing on a car that needs a 3" housing, you are looking at a maf that is reading 36% out (pie are square, right?). dme can't adapt to such a significant change. worse, your engine will be getting more air than it thinks it is and run lean - hard on engines (no cooling). you can do it, but a dme remap is required.

however, it also shows that those who state their intake products require an expensive remap (which they also sell) to realise full benefit are wrong, unless airflow is increased by more than 25% (not likely).

[The Radium King]

manufacturers will compromise air/fuel ratios and engine temperature to improve emissions. often the biggest power tuners tout comes from bumping up the rpm limit (if hp is on an increaseing curve, you will get a 'gain' in hp by alowing the curve to travel a bit futher).

[Brad Roberts]

I have 4 CaymanS engines apart right now with the number 6 rod bearing toasted!!! Please please keep raising those rev limiters!! LOL It'll keep me in business longer!!



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[Brad Roberts]

Here is what I know:

The 3.2 uses a head nearly identical to the 3.4

The 3.4 makes 300hp stock

The 3.2 makes 250hp stock

Porsche CUTS THE NUTS off of the Cayman's and the Boxster's

If I use the same size exhaust and cats from a 3.4/3.6 on a 3.2 and utilize a 3.4 Cayman Airbox and a 3.4 sized throttle body, I *should* be able to make 300hp out of the 3.2 engine without compromising anything. We have already made 250 with a 2.7 with little to no mods.

3.4 has the 3.2 crank with just smaller pistons in the 3.2
3.4/3.2 cams are identical.. (they say 3.2/3.4 on them)

I have the 3.2 car I'm going to test all of this on, and I have a base tune ready for the car based on a 3.4 tune.

As some of you dig in deeper to the ECU's you are going to see the BIG cam timing difference between a 3.4 996 tune and a 3.2 986 tune. Then again with the 3.4 CaymanS tune and the 3.6 996 tune.


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[Brad Roberts]

We have already made 345hp with a stock CaymanS engine and I have other shops with 350hp. We made 345 smog legal with all four cats in place.


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[jaykay]

Hmmm yes a little more power just at the top won't help me much.... Yep I know a Cayman guy that looses at least one engine a season.....they dont like over revs.

For those that have the Cayman box ....how is the proper reprogramming for the larger MAF housing accomplished

[jaykay]

Sounds great...Thanks for the feedback

Same heads??? Wow!

Originally Posted by Brad Roberts

Here is what I know:

The 3.2 uses a head nearly identical to the 3.4

The 3.4 makes 300hp stock

The 3.2 makes 250hp stock

Porsche CUTS THE NUTS off of the Cayman's and the Boxster's

If I use the same size exhaust and cats from a 3.4/3.6 on a 3.2 and utilize a 3.4 Cayman Airbox and a 3.4 sized throttle body, I *should* be able to make 300hp out of the 3.2 engine without compromising anything. We have already made 250 with a 2.7 with little to no mods.

3.4 has the 3.2 crank with just smaller pistons in the 3.2
3.4/3.2 cams are identical.. (they say 3.2/3.4 on them)

I have the 3.2 car I'm going to test all of this on, and I have a base tune ready for the car based on a 3.4 tune.

As some of you dig in deeper to the ECU's you are going to see the BIG cam timing difference between a 3.4 996 tune and a 3.2 986 tune. Then again with the 3.4 CaymanS tune and the 3.6 996 tune.


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[Brad Roberts]

From a manufacturing standpoint.. they will only cast a few parts.

CaymanS 3.4 uses 3.6 heads.... (they actually say 3.4/3.6 on them)

So? why would a 3.4CaymanS only make 300hp? when the 3.6 makes 350? (Porsche cuts the nuts off the mid engine cars)



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[jaykay]

Brad

Just thinking out loud. You may have to consider the merits of the 3.4 intake runner and plenum (left and right) acoustic properties to get the 3.2 to breathe.

[Brad Roberts]

I encourage people to think out loud The 3.4 plenum is taller, but the actual design is not much different (I have about 30 intakes from 2.5-3.6)


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