msitpro

Interesting - so from what Mark at Abbey is saying, if you get a remap with them, don't expect any change in performance before 3000rpm. I'm sure they COULD map that part - making it run leaner - might even improve performance. I think a lot of the mapping changes on a N/A car they do are actually leaning it out in many places.

I wonder if you could also activate that 2000-3000rpm fuel map based on the yaw sensor readings? I think from memory there's not enough ROM space on the Z's ECU to store multiple maps though.

...exactly what me and a work colleague were saying earlier in relation to my idea (he's had 450whp Evo and S14 )

From the reading I've done, it may suggest that the catalysts on the original post by @davey_83 have a lack of the material used to control HC (unburnt Hydro Carbons) More ideas for high HC below from https://www.popularmechanics.com/cars/how-to/a113/1272536/ - maybe your car is much better serviced than the original car from this post and burning leaner. Your issue on HFCs, like mine is on the CO value. This may be due to either the reducing or the converting of carbon monoxide material being less than is needed on the model of catalysts we have - I.E. of 'cheap' build/quality I'm thinking if you had a custom fuel map made, you could lean out 25% throttle at 2000-3000rpm which it's measured at, to 14.7 AFR or higher target.

Hmmm. I wonder if the remap, being a bit richer in patches killed off the HFCs over that year. The richer it's running, the shorter the lifespan of the cats. When you then re-fitted OEM cats, what were your test numbers? CO and HC counts? If the CO % is over 0.1% then it could be that either the OEM cats have also lost effectiveness or that's evidence that it's running richer than stock in the 2000-3000rpm range. Looking at others' results, 0.05 % CO and less seem typical for stock everything with healthy cats.

Don't think the rears have anything to do with engine mapping. Just the front header wideband sensors. Probably not a good idea to map fuel based on a sensor after a catalyst!

I also had this thought... Then googled around and consensus seemed to be that it would heat them too far and destroy them. Think catalysts work best 450-650°C from what I read.

So after reviewing the original post, knowing what I know now through my own experience and talking to Jetex - the original car on this thread probably had some pretty low grade HFCs installed. That CO and HC are REALLY high. @davey_83 do you know what part this person actually ordered? And also whether they have had any ECU tuning? Also note, the OEM cats are actually dual stage with 2 different honeycomb substrate elements, just in a single pipe part.

a remap can indeed affect emissions, in both positive and negative ways depending on the tune. Based on my test sheet yesterday, lambda value at exhaust must be between 0.97 and 1.03 in rpm range 2450-3050rpm to pass, CO% less than 0.2 and HC less than 200ppm. So, if a remap has been set so that between 2450 and 3050 rpm it is running richer than OEM within that rev range then it's going to increase HC and CO and lower the measured lambda. If in combination with that, you have a high flow cat with small diameter (less surface area for the catalytic materials to act on) then this compounds the problem. I can't imagine with a good condition OEM cat internals (like mine when tested last year) that with just a remap you would ever fail. They have a huge margin over the legal limits. From speaking with Jetex on the matter - especially when using high flow cats, the concentration of the palladium, rhodium and platinum substrate coatings is very important. A 'cheap' 200 cell cat may only have concentrations designed for a Euro 2 car (see ebay cheap sports cats <£90) . If you look at ebay for Euro 4 qualifying cats, it's £180 minimum. The reason being that they will have higher concentrations of the precious catalytic materials on the honeycomb. Just off out to a job at work - can't remember exactly what your circumstances were?

This: https://jetex.co.uk/product/5-euro-5-200-cell-catalyst-for-3-pipework/

Looking at just after the Y join. There's a V clamp already. Already found somebody different to weld in another V and the install a cat in the gap. Bonus will be the reduction in volume. A friend's iPhone recorded it at 118dbA at 4,000rpm ... Something veeeery interesting I've learned by chatting with a guy from Jetex, where I may well purchase the 76mm in/out cat, is that the effectiveness of reducing CO/HC will be greatly influenced by NOT the cell rating, but which Euro standard it's aimed at and therefore which expensive materials it uses inside. He was guessing that the units I've had installed are very cheap units. For example, Jetec sell a Euro 4 spec 200 CPSI unit at £180 ish and a Euro 5 spec 200 CPSI unit at £250 ish. Both should flow the same and therefore offer the same back-pressure but the more expensive cat will reduce CO and HC more.

So I thought I'd get my HFCs tested before MOT time. Good job I did. Fails on CO percent. Engine: DE Cat type: custom 200 cell in OEM locations How old are the catalysts?: 2 months. MOT test HC count: 106-125 pp. MOT test CO % volume: 0.37-0.66 % MOT test Lambda value: 0.981-1.029 Has the car been ECU tuned?: No What other performance modifications does the car have?: Injen CAI, DC Sports stainless headers, dual 2.5" to 3" cat back exhaust. What fuel is/was used on the car during MOT test?: UK 98 RON V-Power Going to need a second stage 200 cell cat added.

Personally don't think mileage is worth too much on a 350. Look at paintwork dings, suspension and under body component condition - amount of surface rust or worse. Interior wear, servicing evidence (oil and filter changes), air filter condition can be an indicator. Tyres fitted will show how it's been cared for (look for cheap makes), as well as any curbing, corrosion to wheels, usuals. If it's been kept in a garage and/or only used in fair weather most of its life then I'd snap it up as the biggest killer on these is under body corrosion. Especially check for clunking over rough road especially on passenger side. This indicates non replaceable ball joint in compression arm is busted. Arm needs replacing. Lack of tightness and floaty handling will indicate that suspension bushes have gone. However on a £4.5-6k 12+ year old 350Z then you should replace ALL the bushes with poly in my opinion. The original rubber ones will all be knackered. Budget £2k to buy and pay for fitting of the bushes and arms. It's like night and day.

Cheers for the info - when was that Uprev map done? Was it after the last MOT but before the latest one?

Much shorter than I thought it would be! I assume you mean including loading and check-in? (Tunnel is 35 mins actual moving time) I get what you mean coming from Cardiff though.

How long's the crossing? We did Eurotunnel. About an hour all in each way to cross.

HC of zero haha, you've got the world's cleanest burning VQ35! I assume that's OEM cats to get CO of 0.02% ?

Haha sounds exactly like me. Not done much to my grey Z either apart from drive to Spa and back without any problems. Is that the car park in the paddock? Very jealous if so. We had paddock access but parked in normal parking miles away.

Track duty only though right?! Good news on my spring changes. The road handling is perfection for daily use. Even better, the damping adjustments on the shocks now make huge differences. Running softest on the road but can be stiffened up massively. 8k front, 6k rear 326 Power/Swift Mazibane springs.

Just re-looking at your result.. notice the CO has to be 0.20% to pass and is handily exactly that on your car.... could be too much of a coincidence - did the MOT tester not test/couldn't test or fudge it maybe?? Like I said my last yr cert I'm sure only lists HC value, so maybe the tester has leeway in what equipment they have and whether it's functioning correctly etc.... More food for thought.

Don't think my MOT test form last year had CO %. Pretty sure it was 20ppm on the HC with stock everything though as I remember it being exactly 10x lower than the allowed maximum.

I have read a lot about people adding HFCs (High Flow Catalyst)/Sports Cats and saying they can't get them to pass an MOT emissions test, either from new, or sometimes after a few years of being on a car. I think it would be very beneficial to the community if we could gather some emissions test data in one place to see what works and what doesn't in general. Please could any contributors list in the below format (feel free to contribute any other data that may be relevant) Engine: (DE, Rev-Up, HR) Cat type: (HFC model, decat, OEM) How old are the catalysts?: MOT test HC count: MOT test CO % volume: MOT test Lambda value: Has the car been ECU tuned?: (No, yes - UpRev @ Abbey, Horsham, etc. and year tuned) What other performance modifications does the car have?: (none; or headers, intake, plenums, injectors, ITB, larger TB, spacers, etc.?) What fuel is/was used on the car during MOT test?: (UK 98 RON V-Power, UK 97 RON BP Ultimate, Tesco Momentum 99 RON, etc.) Thanks greatly to any respondents!

Don't catalysts operate better the more heat they have? Although then typing that I'm thinking, actually, the heat will stay in the exhaust components rather than dissipating out... So yeah, that's a great idea in theory - acts as a heat shield to other components and keeps the heat in the exhaust for better emissions. I've not got many good shot of it yet tbh, life been a bit mental recently - any spare time I did have on the car around a month to month and a half ago was making sure it was in tip top shape for trip to Spa to watch the 24hr. Here's a couple anyway, viewing rear and the Y-pipe. I had DC Sports stainless headers (extra smoothed/de-burred inside by me also) installed along with the custom cats and rest of system.

Could you dig out the test cert? Curious to gather a bit of test data from people.

What are your wheel / tyre / spacer? spec with that stance?