Ported Heads vs Passing Emissions Testing

[jmgtp]

I have a set of nicely ported heads begging to be installed. The car is due for e-testing in April I believe. This car doesn't play in the snow so ideally I want to start driving it again in April. I've been putting off installing the heads because I fear they may cause an emissions fail. The car has a high flow cat and that will be staying.

4 years ago it *almost* failed. 2 years ago it passed with flying colors. The ONLY change made was I discovered an absurd sixty something psi in the fuel rail! Clearly the rich condition caused the near failure.

It passed the last test with the EGR turned off and the 13* exhaust cams retard. Mind you, it passed this test with flying colors. I would have used the chip that has the EGR on, but for some reason it gets code 43 with that one.

So, I ask you, will these awesomely ported heads have a negative, positive, or none whatsoever impact?

In case you want to make a well informed decision, as it sits right now:
-91 3.4
-~120k miles
-2.5" cat back, hi-flow cat (magnaflow brand I believe)
-exhaust cams retarded 13 degrees
-96 intakes
-75mm TB and custom plenum arm
-WOT Chip (egr off, lean cruise on)

[torq455]

what does awesomely ported heads mean? do you have CFM vs. lift? what CR and idle speed do you have? lower velocity at idle can cause worse emissions. you can help that by increasing your idle speed. you may have to either lean or richen the idle as well. that can effect emissions too. not quite clear on what "they" look at, or how they test the cars. that info would help too.

[camgrinder]

thats funny-with ex retard and no egr it still passed- ex retard pushes unburned fuel out the exhaust on overlap- the high flow CAT must be one heckuva good unit, its doing a super job of getting rid of NOX-CO-HC to the point the EGR is not missed-so much for the EGR being useful-
ported heads typically make a car go rich in exhaust but if you have a MAF system it will compensate for the ported heads and should adjust mixture to the right a/f anyway, with the stock PCM and chip- but if you have the entire '91 system its speed density and yes it most likely will go rich- its going to be touch and go, put the heads on see what happens next test-you can always put egr back on and try to pass again with the ported heads, if it fails first time-speed density cars seem to run better with stock PCM/chip in them

[1988GTU]

Add some HEET or denatured alcohol to the tank and watch it pass. ... It could make it fail nox though.

[SappySE107]

I doubt the heads make you fail unless it throws the tuning way off. I doubt that very much since I know what the heads look like:P

[jmgtp]

I think I might start tearing into this next weekend. I'm probably going to stage it over a few weekends, as in first weekend tear it down and have the heads off, next weekend transfer valvetrain to new heads (that might be a whole other issue depending on finding burned valves), etc etc. I'm open to ideas on how to keep dirt/dust/moisture out of the engine while its all apart over the span of a few weekends. The car is in a 2 bay garage. The other bay doesn't have a car in it but the snow blower and what not are kept there - there's plenty of dust, water and exhaust flying around in there.

Time to dive back into my original 60v6. I've been completely preoccupied with my other 60v6... dare I say it is a Ford engine?!

[SappySE107]

Im sure your valves will need to be touched up. Exhaust especially. Plastic bags work to keep dirt out.

[camgrinder]

I think I might start tearing into this next weekend. I'm probably going to stage it over a few weekends, as in first weekend tear it down and have the heads off, next weekend transfer valvetrain to new heads (that might be a whole other issue depending on finding burned valves), etc etc. I'm open to ideas on how to keep dirt/dust/moisture out of the engine while its all apart over the span of a few weekends. The car is in a 2 bay garage. The other bay doesn't have a car in it but the snow blower and what not are kept there - there's plenty of dust, water and exhaust flying around in there.

Time to dive back into my original 60v6. I've been completely preoccupied with my other 60v6... dare I say it is a Ford engine?!

disassemble the engine and cover the top of it with large towels to keep dirt/dust/debris out- an old bath drying towel will work good. Find an old sturdy cardboard box and put all the hardware in there.

if the cat converter you bought was a high efficiency modern 3-way unit, you can delete the EGR and still pass emissions. The old OEM 2-way cats only removed CO and HC, and the EGR removed NOX. The new 3-way cats remove CO, HC, and NOX- so that would explain why you had the EGR off and it still passed.

you could also have a very "easy" test at your station, everyone tests slightly different and it comes down to who/where it's actually being done. One place can be a real stickler, while another place will overlook things. Find a station that's easy going and stick with them year to year.

[jmgtp]

I want to say the cat is a 2 way but its been about 2 yrs since I built that exhaust so I don't really remember. The emissions testing is standardized by the state - there's no leeway from one testing station to the next. OBD II vehicles get plugged in to the computer - pre OBD II vehicles, such as my car, run on the dynamometer and get the sniffer test (I have to pull the front air dam off to clear it!). The only hardware check is for presence of a catalytic converter. It passed well under limits last time through and sounds like if the heads are the only change it should do ok this time as well.

Any ideas why my stock chip, memcal, eeprom or whatever else you'd like to call it (with EGR on) would trip code 43? Is the knock filter in the chip? Maybe it is damaged or too sensitive? It trips 43 right at startup and it stays on. The modded chip that Ben made for me doesn't have this problem. Ben would you be able to burn me another STOCK chip that wouldn't have this problem? I can send you the current one if you'd want to see what code is on it.