They said it's best to keep both sets of Lambdas in as they do more than monitor the health of the cats. I've never heard that before but he was adamant that it was better to keep them all.
trouble is if you dont have a cat then it'll throw codes surely, this is why the post cat lambda(s) get coded out?
I thought that, but on research (read: google) it turns out the some post cat lambdas have an influence on ignition timing so maybe that's it? I was thinking of fitting a 200 cell cat anyway.
I would hook up a relay to the SAI control relay signal wire to act as a dummy load. Certainly on the R32 ECUs, it doesn't tolerate a total deletion. Not 100% sure on the 2.8s, but the more you can keep from the original setup, the happier the ECU will be. It needs to see the relay whether you use SAI or not, as it's one of the things it needs to see in order to get your long term adaptations. Definitely keep both front lambdas. They ensure both banks run at lambda 1 at all times. The rear lambdas can go. They just check for lambda 1 coming through the cat. I have experience of the most popular VW tuning houses and my personal recommendation is Stealth Racing.
I tried to get a definitive list of what can be deleted, and what can be done with coding/resistors here: http://www.clubgti.com/showthread.php?238699
I was surprised that United Motorsport said to keep all 4 lambda's but the only things i'm having done with my ECU are Immo defeat and SAI remove. I have since sent an e-mail to ask about the charcoal canister but awaiting response. As much as UM seem a bit short in their e-mail replies, i've heard nothing but good about what they do and what they know so that is why I decided to go with their advice. I'm looking into having a Sports cat so that will cure what I physically do with the rear lambda's. I've also read about most modern NA engine maps not liking the reduced back pressure of a missing cat and results in lost torque in the low to mid range with maybe more bhp up top. I personally am attracted to the lazy way in which a 6 cylinder delivers power compared to the revvy nature of a highly strung 4 pot and wish to keep my lower down torque. I've used stealth before in the past and just didn't gel with them for some reason. I have no doubt that they are extremely good at what they do, but not for me.
yeah the important thing is you go with the recommendations of the guys who are actually tuning it, so you'll get the best out of their mapping techniques
Busy mechanics tend not to be big on communication... they're generally busy doing rather than talking.
you do have to be patient with united motorsport and i admit that my 2mo seemed to drink fuel and they admitted that it was down to having the rear lambdas seleted that they did
IS that supposed to read deleted? If so then hopefully mine wont be too thirsty with a sports cat. I've had good communication with UM but they are not willing to engage in e-mail conversation about their products. Very fast turn around though. I sent out my ECU on Tues and it was sent back to me last night and should arrive back tomorrow (Friday). Something I can't really grumble about at all!
Ive had my VSS, SAI, secondary lamdas all mapped out and had no problems with it drinking fuel. Its a big engine in a little car and with a map and lightened flywheel etc your gonna drive it harder.
/\ Same. Stealth mapped my MK5 R32 engine and in my Corrado it averaged 31mpg. 35 was easily achievable on long journeys at 70mph, which considering my car had a shorter final drive than standard was pretty good. I had a dummy relay for the SAI, rear lambdas deleted and I connected the carbon can purge valve to the ECU harness, but didn't use the CC. It all worked and ran perfectly!
Matt is hard to get hold of at the best of times. Tho his work is top class. I have plenty of friends who have had stuff done by/from him. He knows his stuff where the VR6 engine is concerned
On a 3.2? The only time I averaged mid 20s was when I had the wrong ECU and it couldn't see the exhaust cam sensor. When I ran mine with a DTA standalone, I was seeing mid 30s average and as much as 38 on a 65-70mph cruise. I ran it a lot leaner than VW do in the light throttle areas above 2000rpm and it really boosted the economy. I wish I'd left it on the Standalone instead of going to ME7 to be honest. It drove a lot better and far, far easier to wire up and map.
