Originally Posted by Brad Roberts (Post 271332)

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.

Originally Posted by Marchie (Post 272356)

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.

Originally Posted by The Radium King (Post 271130)

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).

Originally Posted by Brad Roberts (Post 272524)

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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Originally Posted by Brad Roberts (Post 272537)

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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Originally Posted by onaFLYer (Post 272555)

I was thinking of using the 3.4 setup on mine, to go with the airbox and slight bore increase. Sell me one cheap?

Originally Posted by Brad Roberts (Post 272679)

I throw the large cutout section in the trash :) It's a box. The hole being covered is one way in one way out. Cover it, and no air will bypass the filter. We are cutting off a sound chamber/muffler. It is not needed.

I wish I had shot a picture of the air box prior to cutting... I may pull the one out of a CaymanS in the shop right now for an engine rebuild just so you can see the before and after.

Guy's.. buy a new one from Porsche. Trying to find them used right now is going to be difficult.

I posted the part number and the price in a previous post. They are not expensive new.


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Originally Posted by Brad Roberts (Post 272773)

Looked at the Yellow GT3.. spotless.. easy minor damage no tweaking

Originally Posted by Marchie (Post 273724)

Thanks for the pictures , Brad. The thread seems to have gone quiet, lol.
I was kind of hoping someone would give me an answer to my last question, regarding the ipd , larger throttle and what hose setup I would need to order. Any thoughts would be much appreciated.
Bye the way the 987 air cleaner is cheap at around $360 , its the new 987 maf housing thats expensive as it costs about the same as you have to buy the sensor with it. Thanks for your help thus far.

Originally Posted by Brad Roberts (Post 273924)

I highly suggest the IPD and CAYENNE V8 throttle body (much cheaper than the GT3 and its the same size) All those people buying the "GT3" throttle body are being raped.. LOL The V8 throttle body has the connector oriented just a tad different than the actual GT3


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