Jump to content

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

too lean ... any ideas?

Recommended Posts

I have a 987.2 Boxster S with the 3.4 DFI engine an dits modded by TPC racing's low pressure turbo kit.

it runs fine and i can actually compete with R8's (the V8's of course only)

I have this problem though that the durametric logs show a much too lean value

I just logged lambda today and its freaking me out honestly.

I just emailed TPC:

hi mike,

when I went to my garage i did that throttle body thing and brought it to 14V - all good

now - something that still gives me headache - even that the car runs better now - it is still incredibly lean!

what do your DFI boxster or cayman S cars with the low pressure turbo kit have in actual lambda value before cats?

mine is regularly above 1,0 - at times even up to 3,03!

check attached durametric log column F and G are lambda actual values

running too lean can easily bring your engine to blow - you know that more than i do

please have a look and let me know your feedback




so the car is running better than before now - but its still incredibly lean.

can anybody else on this forum, like the recent cayman R build

duramtric log his lambda values - if all DFI cars are driving these

I foresee a dark future for our engine - a very recent dark one indeed


tpc's (mike's) response:

your using durametric you have no idea what those values are its unreliable


thanks - but how does this help exactly?

so I replied:

so what should i do then to get peace of mind on this too lean angst

that i have? who can log or better what system can log real a

head cat values for me correctly?

...so lets see

the guys on the german tuning forum

they drive driving porsche factory turbos modded up to 600-1000 hp

are telling me do NOT drive the car with this kind of lamda valuesfrown.gif


I have attached two durametric logs - I have to admit the support from tpc is at times very difficult

so you got to figure things out on your own i am afraid. What do you guys say about the durametric's values reliability?

I understand all around the world it used even for ECU mappings - so that would be strange if its values were not usable - would it not?

thanks for constructive participation

dura logs.zip

Link to comment
Share on other sites


Have you looked at the long term fuel trim (RKAT, FRAU, FRAO) values for both banks? Also, DFI engines are made to be able to go leaner, but I don't know what the limit is. Another thing is that those vaues are not consistent as I noticed that lambda is around 1.0 throughout various rpms but at some point it jumps to 3.0+ for the same range of rpms.

BTW, you're tracking too many actual values with Durametric -- this tool, like many others for various OEMs do well when only tracking a small amount of values. Just read the actual lambda values for both banks and rpms only and see what the results are.



Link to comment
Share on other sites

Here is lambda1 logged

appears not too lean - but I will have someone

with experience give me a feedback and I will re-confirm those

values with the porsche tester tomorrow

here is another concern

are those 6MT vs 6MT?

or PDK vs PDK?

at least same type vs same type?

because in all reality my car would NEVER EVER beat a GTS modded 987

here is a fact - my 100-200 km/h time is a flat 11sec

sometimes a tiny bit lower - and my car is a PDK!

to compare - a friend in germany has a gen1 car with a 911

3.6 engine conversion that delivers at 355 crank hp

he is driving an 11.7 (2 shifts 2-3 and 3-4)

so again people - i do NOT intend to bash TPC or anything

but I want people to know the TRUTH about the REALITY of the mod

they intend to do - and we, the customers, the people,

should put our results together to create a reliable feedback

on what those cars and mods really deliver

:thanks: for sharing your durametric and/or 100-200 runs with another

I would also ask TPC - since troubleshooting over the net is difficult,

why would you not try to create data that is of helo, as a benchmark

why would TPC not have duramteric logs


b1 actual and nominal lambda before cats and rpm


b2 actual and nominal lambda before cats and rpm


fuel delivery relevant values and rpm


mass air flow, load and rpm

see what i mean - it would take them a 3 hour of work to create those logs and then if a customer has a problem - tell him to compare his log runs with theirs - right now anything i sent them if looked at, at all - would never get a straight answer or solution - that if you got mike on the phone - it a little like

Never Get A Straight Answer and I thought Nasa was hiding the exisitence of aliens from us ;)

anyhow I hope we as users - can help each other with creating logs and

benchmark data - or if all may have the same "problem" as I am facing

one thing is a fact THIS:

is NOT my car's reality, and I checked and replaced so many things

and I do NOT have any fault codes either

thanks everyone

lamba 1 new.zip

Edited by Loren
Link to comment
Share on other sites

k went to porsche today and logged with piwis

lambda ahead of cat looks fine at full load and top rpm around 0.79

and when you go off the gas it always goes around 1.0

so basically this looks ok

what the porsche technician spottet though was the values AFTER cat

he said those were moving quite a lot - and they should be rather

constant values

based on that the porsche technician said he would check the kats

possibly they may be stuck.

I emailed TPC:

so what is the course of action now mike?

should I take them out and empty them for a test?

would this interfere with the ECU programming?

or should I get other possibly sport cats?

if so which ones would you give an ok for?

please advise - thank you


so lets see...

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.