Failed emissions with HFC's

[davey_83]

Mate with new HFC's on his 57 plate today failed his MOT on emissions. Before having to pay to swap back to OE cats, is there anything we can recommend to try first?

 

Been thoroughly warmed and even a fuel cleaner put through.

 

 

Edited May 3, 2019 by davey_83

[ZMANALEX]

Yes, give it a good roasting on way for retest and get the temps up as high as poss.

 

Works most of the time.

[davey_83]

He goes got the cats real hot before the MOT, well as hot as he should need to given the cost to supply get fitted. Cats swapped today and hopefully then will be ok for that issue.

[MDMetal]

My regular garage told me mine just scraped by this year they get it roasting hot. The HFCS are 7 years old now so not sure if that's the issue or perhaps some oil in the exhaust? So might well be in a similar position soon

[davey_83]

To be expected after years and years of use, not 6 months. Always a gamble I guess with HFCs sadly.

[longsh07]

Depends on the car somewhat too. My 05 DE won't pass with HFCs, even when they are red hot. Tried both brand new Berks and second hand Cobras but no luck. My mechanic (Japex) said they've seen it before where some cars just won't get through with them and some will scrape through. 

Edited May 5, 2019 by longsh07

[msitpro]

On 04/05/2019 at 21:47, MDMetal said:

My regular garage told me mine just scraped by this year they get it roasting hot. The HFCS are 7 years old now so not sure if that's the issue or perhaps some oil in the exhaust? So might well be in a similar position soon

Do you have any ECU tuning, or stock tune?

[msitpro]

On 05/05/2019 at 20:40, longsh07 said:

Depends on the car somewhat too. My 05 DE won't pass with HFCs, even when they are red hot. Tried both brand new Berks and second hand Cobras but no luck. My mechanic (Japex) said they've seen it before where some cars just won't get through with them and some will scrape through. 

Tuned, or stock ECU?

[longsh07]

On 07/08/2019 at 20:25, msitpro said:

Tuned, or stock ECU?

UpRev remap by Abbey Motorsport.

Edited August 24, 2019 by longsh07

[msitpro]

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.

Edited August 27, 2019 by msitpro

[davey_83]

Were Torqen HFCs and mapped with Horsham Developments.

[longsh07]

I never actually got to test this theory but I wondered if wrapping or coating HFC's in exhaust wrap or ceramic heat paint would help keep the heat in and make them more efficient. I was told it wouldn't make enough difference in my case and I dare say based on the numbers in the first post, your friend will be in the same position.

[davey_83]

Do mapped cars with HFC's and rear O2 sensors switched off pass a lagit MOT for emissions? I understand the rear sensors don't effect the every day performance of the engine, however does it effect the emissions on test? 

[longsh07]

Mine was exactly that. Mapped by Abbey with new Berk HFC's fitted and the rear O2's disabled for the purposes of stopping it throwing engine codes. It passed one MOT barely the first year after fitting then that was it, never again.

 

Fitting the stock cats back on the car without getting another remap bought emissions back in check right away. Having the rear O2 sensors off has caused me no issues whatsoever with HFC's fitted or after refitting stock cats.  So in theory, no, having the rear O2 sensors off makes no (or at least negligible) difference to emissions, all about the cats I'm afraid.  (EDIT: Photos below of emissions print outs confirms this)

Edited August 28, 2019 by longsh07

[msitpro]

6 hours ago, longsh07 said:

I never actually got to test this theory but I wondered if wrapping or coating HFC's in exhaust wrap or ceramic heat paint would help keep the heat in and make them more efficient. I was told it wouldn't make enough difference in my case and I dare say based on the numbers in the first post, your friend will be in the same position.

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.

[msitpro]

1 hour ago, davey_83 said:

Do mapped cars with HFC's and rear O2 sensors switched off pass a lagit MOT for emissions? I understand the rear sensors don't effect the every day performance of the engine, however does it effect the emissions on test? 

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!

[msitpro]

1 hour ago, longsh07 said:

Mine was exactly that. Mapped by Abbey with new Berk HFC's fitted and the rear O2's disabled for the purposes of stopping it throwing engine codes. It passed one MOT barely the first year after fitting then that was it, never again.

 

Fitting the stock cats back on the car without getting another remap bought emissions back in check right away. Having the rear O2 sensors off has caused me no issues whatsoever with HFC' or after refitting stock cats.  So in theory, no having the rear O2 sensors off makes no (or at least negligible) difference to emissions, all about the cats I'm afraid.  

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.

[longsh07]

49 minutes ago, msitpro said:

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.

Luckily I've recently sorted all my paperwork as the car is up for sale.

 

This is full stock exhaust - no remap (2014)

 

Milltek exhaust, new Berk HFC's, and remap (2015). Initial fail numbers, passed on retest a few days later but don't seem to have retest figures with the cert. 

 

Second hand cobra cats, no change to map (2016)

 

Back on stock cats, no change to map (2016)

 

Still on stock cats with no change to map (2019)

[longsh07]

Major difference I've noticed between my pictures with HFC's fitted and @davey_83s picture is the HC value. Do we know what conditions affect the CO and HC values?

[msitpro]

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.

 

Quote

Hydrocarbon emissions are simply unburned fuel being pumped raw into the exhaust system. Misfiring is the most likely culprit, and that can come from an ignition problem, or an internal engine failure that reduces compression. Another possibility is a mixture that's too lean to catch fire dependably because of either a fuel system malfunction or a vacuum leak. If a high HC number isn't from a miss, it's probably due to an overly rich mix.

So, worn or fouled spark plugs are the first things to suspect. If you can feel a dead miss at idle, use insulated pliers to pull plug wires one at a time to see if one in particular does not have any effect on smoothness (don't do this on '96 and newer cars with OBD II, as it will set a misfire code and turn on the Malfunction Indicator Lamp on the dash). Remove and inspect that spark plug. If it's okay, use an ohmmeter to find out if the plug wire is open--you should meter 5000 to 20,000 ohms, then examine the distributor cap for heavy corrosion in the sockets, cracks, etc.

With the plug out, do a compression test--anything much less than 100 psi should be suspect (a valve may be burned). Also, look over the intake manifold to see if there's a vacuum tap in the runner leading to the problem cylinder. A leak here can lean out the mix to the point of misfire at idle.

There are a couple of other things that can supply enough extra gasoline to put hydrocarbons above the limit. One is the evaporative-emissions control system that traps gasoline vapors that would otherwise escape into the atmosphere. It then meters the vapors into the intake during off-idle modes to be burned. If it flows at idle, the mix will be too rich.

Another potential culprit is engine oil that's diluted with gasoline. Fuel vapors are drawn through the Positive Crankcase Ventilation system and into the intake manifold. Smelling the dipstick may tip you off to this, and an oil change will correct the problem--temporarily.

 

[davey_83]

No that's an idea a valet mode which doubles as an emission friendly settings for MOT's

[longsh07]

5 minutes ago, davey_83 said:

No that's an idea a valet mode which doubles as an emission friendly settings for MOT's

https://en.wikipedia.org/wiki/Volkswagen_emissions_scandal  

[msitpro]

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

[msitpro]

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.

[longsh07]

Depends on year according to Abbey. The newer cars had more ROM on the ECU. My GT4 (so 2005) has 5 maps selectable on the fly through cruise control.

 

I didn't broach the subject of an 'MOT mode' specifically with Mark but I did ask if the remap could effect emissions. He said 'we don't adjust any of the maps around the MOT area's' - I take that to mean engine speeds.