logging it of course is best. You want the open loop numbers, that is when all the sensors are doing their thing and you are at WOT wide open throttle. The closed loop stuff will fluctuate but always kinda read like what you have gotten already. Closed loop is just cruising or idling. You want your open loop numbers to be around 13:1 for best performance. (disclaimer) I was advised this by somebody but please have your car tuned by a professional for safety of the motor and performance. Pedro can probably help or FVD. Giac if you can get them to get you on their dyno. I use a wideband 02 sensor.

I'm just wanting to make it the best I can lol. I could not keep the Helmholtz resonator on the tube. There was no room for it, so it had to be removed.

Ok, so I'll get my daughter to ride with me, lay the hammer down and have her log the info. She got to ride in it for the first time this morning. I have the speed gong set at 70, so I know to slow down to keep the spoiler from deploying. She heard the ding at said " we hit 70 already?" lol.

FWIW, here is a good study of air filters. I like tests with real data and there is a lot there. Bottom line, there is no free lunch. Interesting read if nothing else...

@KRAM36

You're welcome. :D ;)

Don't forget that your AT-tranny will need an defined amount of variable underpressure to work perfect, and that the intake tube is designed to deliver exactly that underpressure. ;)

Also consider not also the Helmholtz but also the Venturi effect when you do things in a new sophisticated KRAM36 way. ;)

Check out this video. This car also has a flat 6 in it and got a 5.7+ whp with just the K&N filter added. Also the longer the K&N filter is in the car, the better it traps dirt.

<iframe width="640" height="360" src="//www.youtube.com/embed/3DbkmThHYMs?feature=player_detailpage" frameborder="0" allowfullscreen></iframe>

I *think* the tip connection is only for vacuum, so not a lot of, if any, air movement through it.

you will need a wideband o2 sensor to measure afrs at wot. your car only has narrowband (ie, measures afr values in/around 14.7). ecu uses feedback from the narrow band sensors to keep afr at 14.7 at idle and part throttle though the use of fuel trims (ltft). this is closed-loop operation.

at wot the ecu wants to add a bit more fuel to keep things cool (ie, an afr of 13 as suggested by jaay). narrowband sensors don't work in this range so the ecu has no feedback on the afr it is providing - it just adds fuel based on the amount of air measured. this is open-loop.

open loop is the most critical, as this is when the engine is working hard and the opportunity for damage the greatest. if the maf is mis-reading air (ie, more air getting in than the maf reads) you may get into a lean situation which can kill your engine (gets hot, detonation occurs, pistons get holes in them).

how can the maf misread air? a larger diameter maf tube will do it. non-laminar flow in the tube can do it (ie, as jay notes, the ecu is calibrated to read airflow based on a certain type of airflow, and this airflow can be modified by bends - or the lack thereof - upstream of the sensor) vacuum leaks can do it, vibration can do it (ie, I thought it was good to have the maf closer to the tb for better throttle response, but this also resulted in the transmission of more engine vibrations) etc.

the thing is, all the factors that affect air metering at open loop operation are present at closed loop operation, so, check your ltfts and see if they are high. If they are then your open loop afrs will be off (my understanding is that the ecu does not use the closed-loop ltfts when running open loop). a little bit of lean operation is ok; Porsche oem afr at wot is 12.5; moving to a 13 should be fine (will result in more power and better fuel consumption) as long as you use a higher octane fuel.

blah blah blah ...

Radium<<<<<<<<<<< Thank you for the better explanation.

How can I check the ltft? What is too high? Don't I need more miles on the car after the mods (less then 100 miles right now) before the computer sets the ltft?

actually - you are the man here, as you've actually gone in with a piggy back and modified your fueling. perhaps you could help me - does the ecu use the trims established in closed loop operation to modify fueling when running open loop? you could probably determine that by resetting your ecu - as it re-adapts and resets trims, do you see open-loop fueling changing?

I read Loren's response, but how do I equate that info into ltft? Loren doesn't say what the values should be.

I don't understand. :confused:

You could always stick your car on a dyno and get a plot of the afr across the rev range. My afr / fueling seems pretty good as is so it's hard to see aside from a bit more advance where you can make any significant inroads.

That makes more sense to me.

My readings at idle and engine fully warm.

Range 2 (FRA) Bank 1 = 1.08
Range 1 (RKAT) Bank 1 = 2.86
Range 2 Lower (FRAU) Bank 1 = 1.08
Range3 Upper (FRAO) Bank 1 = 1.00

Range 2 (FRA) Bank 2 = 1.11
Range 1 (RKAT) Bank 2 = 4.13
Range 2 Lower (FRAU) Bank 2 = 1.11
Range3 Upper (FRAO) Bank 2 = 1.00

Not sure which MAF reading he was referring to as there are 2 to read from.

MAF (HFM) danced between 11 to 13
Mass Air Flow danced between 10.9 to 11.7

I'm also getting P0430 on the Quick Test
Porsche Fualt Code 45 Cat Conv. Efficiency Bank 2

So I gather from those readings at "WOT" open loop (FRA FRAU FRAO) my AFR is pretty much spot on, but at idle closed loop (RKAT) the AFR is running extremely lean?

these are closed loop values - no trims generated when at open loop (no feedback from the o2 sensors, so no trims). your fra numbers look good - oem Porsche is +/- 0.1. from what I understand, either

(a) your maf is mis-reading the airflow 10% low - vacuum leaks adding air, turbulent airflow into the sensor, vibration, old maf sensor, dirty maf sensor (oiled filter ...) or

(b) your fuel system is delivering 10% less fuel than requested - dirty injectors.

again, the 10% is within Porsche spec, so looks all good (although you might need a few more miles to get the ltft to settle down).

dunno much about idle, other than, if it is idling ok, then I wouldn't worry about it.

did a bit of searching for you and the rkat is high. did you reset the ecu? otherwise perhaps check for air leak. a small leak has more effect at idle than it does at part or full throttle.

Does disconnecting the battery reset the ecu or do I have to do that with the Durametric? The car set for around 5 days with the battery disconnected.

14.6:1 is normal for cruise and idle. That number bounces around a bit but is fine. I use an aem uego wideband gauge and sensor to tune up my car along with a piggybacked air flow manipulator. I use an old apexi afc select. I believe any newer one would also work. I dont have logging software but just do it the old school way. Either on a dyno or a good old stretch of road and 4th gear.

I read your thread on this, pretty slick.

So there is no way for me to get the AFR at WOT, except to change the O2 Sensors (not sure if I'm correct on that) or take it to a dyno?

not change - add - a wideband o2 sensor. it's pretty standard tuner kit - sends signal to an afr gauge, datalogger, etc. typically use bosch units so threads are universal - check you exhaust for a spare bung (preferably before the cat). if not a permanent install you could probably just install in place of a post-cat o2 sensor and put up with an emissions code for a while. plx devices also make a unit that has a narrow band output so that you should be able to install in place of an oem 02 sensor.

this will give you wot afrs. however, if your trims aren't too out of whack when running closed loop then it is a safe assumption that you're ok open loop.

Not to high jack but is there a "power commander V" with wideband sensors and auto tune style piggy back for the ECU that is available? I see we don't have a TuneECU freeware or of the like for the home tuner.

Very nice, thank you.

I did a vacuum leak test today. I did a very thorough check and the only place I would get a stumble at idle was at this port valve circled in red. Had my daughter run the engine up to 2k RPM and no stumble at that port valve.

http://i59.tinypic.com/2yl8zcx.jpg

I also rechecked the KRAT numbers, they have changed, but still way off. Possible the Porsche Fualt Code 45 Cat Conv. Efficiency Bank 2 could be causing this high number on bank 2?

http://i60.tinypic.com/25u61pj.jpg

Just went out and checked some numbers this morning.

http://i62.tinypic.com/ekoz7a.png
http://i61.tinypic.com/2mgseww.png
http://i59.tinypic.com/23tqkv7.png
http://i61.tinypic.com/2ic7h42.png

Here's an AFR plot from a dyno for comparison. 4th gear WOT.

http://i.imgur.com/YbBDY7L.jpg

Where would I look for to fix the fuel tank ventilation?

http://i61.tinypic.com/2ic7h42.png

That's nice to know, thanks.

After the intake upgrade, I'm not sure if I would want 400HP lol. The car is getting down the road is a massive hurry right now and I still have the headers, cat delete pipes and Borla exhaust to do. Also thinking of opening up the intake pipe some more along with a tune.

I was looking at 330HP to put the car on par with the new 2015 Mustang GT hp to weight ratio. I think my car would actually need 343HP to achieve that.

EDIT: Side note: I am looking at some light weight wheels right now and the exhaust change should lighten the car up a bit.


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Fuel ventilation is the EVAP system.

Thanks JFP in PA. I looked at this article on Pelican.

Pelican Porsche Tech Article - Replacing Your 996 Fuel Line Vent Valve / Bleeder Valve - Porsche 911 Carrera & 986 Boxster - Porsche 996 Carrera (1998-2005)

I do not get any of these symptoms and never had a fault code show up on the Durametric from it.

The system in your car is a little more complicated than just the one valve that was covered in that article:

http://i1140.photobucket.com/albums/...temdiagram.jpg

I'm not sure where to go from here. It seems if you have a EVAP issue your car will throw a fault code. I also read it could be the gas cap or from over filling the tank. When I fill up with gas I stop when the gas handle clicks off.

EDIT: Just went out and looked at my gas cap. The seal ring has several cracks in it, a couple of them at least 2mm wide.


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EVAP systems can remain is the "fail" or "not ready" state for prolonged periods after code resets, battery swaps, etc. without registering a hard code or a MIL. If you do a search on the subject of getting the DME to reset itself before going to emissions inspection, you will find that some people had to drive the car for several or even many driving cycles and miles before everything reset to "ready"; during which time the car registered "fail" on the readiness test, but threw no codes, so do not expect the car to quickly clear itself if it is something as simple as a gas cap.

Roger that. Thanks!

EDIT: JFP if I still have your attention, what do you make of the RKAT numbers being so far off? I checked for air leaks and only found that one port valve that would stumble the idle.

Also Duramtric shows misfires in cylinder 3. I changed the coil and plug, but still get the misfires at idel. It's not throwing a code for the misfires and on the highway it never showed a misfire for about a 25 min drive, could it be the fuel injector?


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