Tricky-Ricky

The secondary cat monitor O2 sensors have no influence on maintaining AFRs, they are purely to monitor cat efficiency.

Interesting comments considering that everyone thinks that the Z ECU will dial out/not realise any performance improvements added, and if you say that adding a free flow filter and exhaust is allowing more air, and so using more fuel, then where is the resulting performance improvement??

Have you done a compression test? and I would advise a leak-down test as well it will help diagnose exactly what the problem is, I would not think a DE with 50K on the engine would be suffering from ring seal problems unless severely abused, its the rev-up version that's known for ring seal problems and not the DE.

Of course I understand that, but if your going to drive up a steep hill in 6th the engine is going to fell odd, unless your already doing a high speed, so from that we have to draw the conclusion that the engine is feeling labored in all gears, so if the P0430, TW CATALYST SYS-B2 is a recent CEL and not one that not been previously cleared, then if the cat has collapsed/broken up its possible that its the cause of the problem, however I would also expect to see a CEL relating the the cat monitor O2 sensor as well. To the OP have you tried clearing the CEL and drive and see if it comes back? or monitor live data if pos?

Sorry but why would you want to drive up hill and keep the car in sixth? that's why it has a gearbox!

Here is a pic, its a 370Z but its essentially the same, depending on the clutch adjustment it can feel a little weird, I removed mine, and really couldn't feel much differers in effort,

Sounds like the "lump" you describe could be simply the effect of the assist spring.

You can just use 2K paint, that way you can choose any colour you want, 2K will take engine heat no problem, I have sprayed bike engines with it.

Welcome, unfortunately I sold my Skyline 350GT last year, but have a pretty fair amount of knowledge of them, also we have a dedicated section for them over on the Skyline owners club, so pop over and say hello.

The other thing that has a profound effect on clutch feel is the clutch assist spring arrangement, I junked mine at an early stage, didn't really notice any great difference in the effort needed, this is one of the reasons for the odd feel if you over adjust the clutch disengagement point.

Are you sure they are positive and not negative offset? Z wheels are normally negative offset.

Have you not tried contacting the makers of the bearings/shells for the recommended clearance?

What is the offset of the wheels themselves? if they are less than 35 you will definitely have contact arch problems with those spacers.

Budget wise SC would be the best option as you can get away with std internals if you keep the power/torque pretty modest, I personally wouldn't trust the std motor past 380BHP 350ftlb myself, people do push it to more by its your choice, if you go TC then your looking at a rebuild, as you will really need to go forged pistons and uprated rods, also lower the compression ratio, to make the most of it, so it will be more expensive. Feel wise SC power delivery will be far more liner, and TC will give you more drama.

I haven't got a what, but I do have a when in good used condition, that you can have cheap!

Short answer, no! but the engine does.

Mine was the same, I have fast motorbikes & cars but I got flashed by a mobile camera as I was over taking a lorry on a piece of dual carriageway in an old Diesel golf! The most annoying thing was I was in no rush that day so I was just cruising at 70mph for miles & miles. I pulled out to over take a lorry who was doing 58mph and because I was doing 70mph I ended up with a queue of cars right up my back side all itching to get by me as I overtook. So, foolishly I tried to get past the lorry slightly quicker to let the cars past and my speed crept up to about 80mph. Once I got by the lorry I slowed back down to 70mph but it was too late, the mobile speed trap flashed me at 80mph in a 70mph so 3 points & fine. Talk about sods law. That's more or less exactly what hapend to me! 79 in a70, but I am sure my GPS only said 74, but if you contest it you just get fined more!

No unfortunately not, they don't teach you to spot scamera vans at a distance!

I have just had a NIP grr! had a speed awareness course just under 3 years ago so wont get another, most insurance companies are not bothered about the course but some ask, and most don't make any big adjustment's for an SP30, mine has only gone up by £30 from last year so not much and it tends to creep up every year anyway, but then I'm an old git. The most annoying thing is that after may years of riding fast bikes, and big power cars, and never getting any tickets I have now had two, one in the 350GT and one in a diesel!

Where does the heat soak bit come from? heat soak only takes place when the car is stationary or slow moving and the airflow is slow, once the car is at normal speeds (providing that you don't have a cone filter that doesn't have a decent cold air feed directly to it from the outside air) The airflow will prevent any detrimental effect from heat. The std air box with a decent filter will be far better, as it has a reasonable cold air feed, which can be improved with a little ingenuity.

I think you can see any knock live or recorded in the Up-rev software, I presume your going to be tweaking the map so need to listen for det, personally whenever I tune an ECU I always use det cans anyway, with electronic your dependent on its being dialed into the correct frequency and there is always the possibility of false knock from mechanical component's, Its fine for general safety monitoring once your all set up though.

Didn't say that it was son... Just sharing an experience. LOL! OK dad, although i am probably old enough to be yours

Newsflash, 350Z not the fastest car on the road, and on that bombshell I'll say goodnight.

Presuming yours is a JDM car? sensor 1, bank 1 and 2 are the primary lambda sensors and these are the ones used by the ECU to control fueling, yours seem OK but it will obviously depend on the conditions during the test, bank 2 are the cat monitor lambdas and in my experience the engine will run quite happily without them, (just throw a CEL) I would be looking at plugs, coil packs and associated wiring, you right a misfire will result in odd lambda readings, usually a false lean,

If you read the very first post in this thread this explains how to adjust the bite point of the clutch.