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mike1324a 01-30-2006 12:28 AM

An idea for passing emissions with a turbo
 
I was trying to think of a way to pass emissions with a turbo. Would it be possible to have a custom midpipe with 2 (maybe more) high-flow cats on it and pass emissions with the turbo installed? Just an idea. Install this pipe when ever you want to get tested for emissions and then take it off afterwards. Would this put too much back pressure or anything on the system to be a danger? What do you guys think? Is this possible, could it work?

Red Devil 01-30-2006 10:53 AM

This is why most, if not all, factory turbo systems have downpipes with catalysts. At least all the turbo RX-7's had this. It's there to heat-up the exhaust gas because heat is what causes the needed chemical reaction in the catalyst. It's not the number of cats, it's the heat that is needed at start-up that's the problem.

Along those lines, I always thought maybe having some sort of bypass valve to go around the turbo and straight to the converter at warm-up may address this issue. Then again, I may be missing a very important technicality.

rotarygod 01-30-2006 10:55 AM

If you have a cat installed already, I'd just go get it tested to see what happens.

rkostolni 01-30-2006 11:12 AM

The problem with MD, VA, and a few other states, is that they don't actually sniff your car's exhaust. They just plug into the OBDII port and look for any codes. No codes, you pass. I think that's much more difficult to get around.

The Greddy turbo was submitted for CARB approval already by Greddy. It will take a few years, but Greddy must believe the car will still pass emissions.

MazdaManiac 01-30-2006 11:30 AM


Originally Posted by rkostolni
The problem with MD, VA, and a few other states, is that they don't actually sniff your car's exhaust. They just plug into the OBDII port and look for any codes. No codes, you pass. I think that's much more difficult to get around.

Why not just have your car in a good state of tune so that it has no codes? That is what I've done.:ylsuper:

rkostolni 01-30-2006 12:49 PM

How does your ecu not throw a code when you have AFR richer than the stock ecu wants to see? Most people, if not everybody, using the Interceptor has CEL's for system too rich. The only reason the emanage users don't is due to the cold temp dongle.

mike1324a 01-30-2006 02:41 PM

In terms of sniffing the exhaust, all that is needed is good, thurough warm up before hand and passing in turbo form is possible? In georgia i believe they use the direct computer hook up as opposed to the actual exhaust pipe. Is there any way to pass that, or any loop holes?

cgrx 01-30-2006 02:56 PM

change cars

MazdaManiac 01-30-2006 06:12 PM


Originally Posted by rkostolni
How does your ecu not throw a code when you have AFR richer than the stock ecu wants to see? Most people, if not everybody, using the Interceptor has CEL's for system too rich. The only reason the emanage users don't is due to the cold temp dongle.

Well, the dongle isn't why the E-Manage doesn't throw a CEL, but you can do a similar trick for the Interceptor that spoofs the front O2 sensor.

rkostolni 01-30-2006 06:57 PM

If you have some free time later some more details for that mod would be greatly appreciated!

MazdaManiac 01-30-2006 07:03 PM

You would need to construct a dongle like the one that Greddy now includes to defeat the CEL that results from the air pump issue. It is just an SRC with a resistor.
Then, you would hook it up to turn on when under boost.
You would have to fool with resistance values so that it reads approximately 13:1 or so.
A high-power, multi-turn pot would probably be best and you could monitor the resulting value with a CAN scanner.

zoom44 01-30-2006 07:24 PM

how soon does the CEL come on? if you have a can scanner just clear the CEL.

FLybOi drE 01-31-2006 09:36 AM


Originally Posted by zoom44
how soon does the CEL come on? if you have a can scanner just clear the CEL.

i've read they're very sporadic...theres no way to know how long it will stay on or off...i have a b&b testpipe and had a CEL for a while, and now its been gone for 2months now...weird but im not complaining :mdrmed:

adrian-1 01-31-2006 11:41 AM


Originally Posted by zoom44
how soon does the CEL come on? if you have a can scanner just clear the CEL.

With my interceptor, the CEL reappears after a few minutes of clearing it. Due to the idle being rich.

rkostolni 01-31-2006 01:04 PM

Same here. Even without going into boost it will show up after 3 or so drive cycles.

I wonder if there be any problem with fooling the O2 all the time, as far as affecting anything like DSC, or ABS?

drifter_d 01-31-2006 08:19 PM


Originally Posted by MazdaManiac
Why not just have your car in a good state of tune so that it has no codes? That is what I've done.:ylsuper:

Man, I've been trying to either get transfered or find another job in AZ for a long time, so it ain't for a lack of tryin'! Have family living in Tucson, but I'd love to settle in Phoenix, which is where you're at, if I remember correctly. Maybe I'll send YOU my resume... lol. Warm wishes from cold and windy MD.

MazdaManiac 01-31-2006 10:51 PM


Originally Posted by zoom44
how soon does the CEL come on? if you have a can scanner just clear the CEL.

You will fail emissions if the PCM has been cleared too recently.
The emissions computer can tell if the car has had enough drive cycles to establish the CAT efficiency and idle standards table.

zoom44 01-31-2006 11:10 PM

well there ya go.

MazdaManiac 01-31-2006 11:14 PM


Originally Posted by drifter_d
Man, I've been trying to either get transfered or find another job in AZ for a long time, so it ain't for a lack of tryin'! Have family living in Tucson, but I'd love to settle in Phoenix, which is where you're at, if I remember correctly. Maybe I'll send YOU my resume... lol. Warm wishes from cold and windy MD.

Well, that is not quite what I meant by "state of tune", but that is clever.
Actually, I don't know what the emissions standard is here in AZ. I suspect it might be strict because of its poximity to Cali.
I'm not going to register here until I have to since the taxes are high on new-ish cars. Probably two years when the emissions test in MD is about to expire.

BigOLundh 02-01-2006 06:14 PM


Originally Posted by MazdaManiac
You would need to construct a dongle like the one that Greddy now includes to defeat the CEL that results from the air pump issue. It is just an SRC with a resistor.
Then, you would hook it up to turn on when under boost.
You would have to fool with resistance values so that it reads approximately 13:1 or so.
A high-power, multi-turn pot would probably be best and you could monitor the resulting value with a CAN scanner.

I am sure if you constructed this you could sell a ton in a heart-beat. Essentially every person who owns the interceptor-x would probably want one.

GTR 02-02-2006 02:10 AM


Originally Posted by MazdaManiac
You will fail emissions if the PCM has been cleared too recently.
The emissions computer can tell if the car has had enough drive cycles to establish the CAT efficiency and idle standards table.

In California, The BAR97 machines just makes sure that your OBDII monitors has ran and that they're no DTC's set. By California smog rules, you are allowed only two monitors incomplete.

Umbra 02-03-2006 12:54 PM


You will fail emissions if the PCM has been cleared too recently.
So your saying if the car has been in storage without a connected battery it's going to fail emisions if it isn't driven a while before hand?

MazdaManiac 02-03-2006 01:04 PM

Probably. I don't know how long the NVRAM cap will last without being grounded.
If, when you go to start the car, the DSC and power steering lights are on, your drive cycle info is gone.

TeamRX8 02-03-2006 07:45 PM

I have't been following the Interceptor stuff, but is there some reason you can't make a leaner "emissions purpose only" program; slap it in there, putter around to get the necessary drive cycles, get your test, and then back to your normal program?

GTR 02-03-2006 08:36 PM


Originally Posted by Umbra
So your saying if the car has been in storage without a connected battery it's going to fail emisions if it isn't driven a while before hand?

That is exactly whats going to happen if none of the OBDII monitors are not complete. Try it. Any CAR 1996 & newer. Disconnect the battery and you will fail the smog inspection in California. A lot of people still think they can disconnect their battery to clear that check engine light before they go to the smog station. I catch so many people lying that way. :rock:

GTR 02-03-2006 08:37 PM


Originally Posted by TeamRX8
I have't been following the Interceptor stuff, but is there some reason you can't make a leaner "emissions purpose only" program; slap it in there, putter around to get the necessary drive cycles, get your test, and then back to your normal program?

I am not familar with the Interceptor so I can not comment.

mike1324a 02-05-2006 02:26 AM

Is it manditory to check through the OBDII port? Can you opt for a true exhaust reading instead?

rkostolni 02-05-2006 11:40 AM

It depends on the state. Usually, they pick one method or another. In MD and Va the only method for testing cars with OBDII is through the port. It kinda seems stupid to me, because all that really matters is does your car pollute beyond the set limits. So you should be able to opt for a smog check, but you can't.

MazdaManiac 02-05-2006 12:11 PM

They only sniff pre-OBDII vehicles.

GTR 02-05-2006 12:43 PM

In California, They measure tail pipe emissions on a dyno and use the OBDII port to check to see if the MIL has been commanded on and if the OBDII monitors are complete.

TeamRX8 02-05-2006 03:29 PM


Originally Posted by TeamRX8
I have't been following the Interceptor stuff, but is there some reason you can't make a leaner "emissions purpose only" program; slap it in there, putter around to get the necessary drive cycles, get your test, and then back to your normal program?


Bueller .... anyone? :dunno:

Umbra 02-06-2006 10:53 AM

How much driving is necessary to get the car to pass emissions after a reset?

MazdaManiac 02-06-2006 11:28 AM


Originally Posted by Umbra
How much driving is necessary to get the car to pass emissions after a reset?

It has to be started cold and run for at least 12 minutes or so a total of 4 times.

mike1324a 02-06-2006 02:24 PM

I think theres some highway miles needed in there too

MazdaManiac 02-06-2006 06:19 PM


Originally Posted by mike1324a
I think theres some highway miles needed in there too

I think you are right. I think the RPMs have to be held over 4k for a minute or two in two of those drive cycles.
The pattern is in the "after repair" procedure in the FSM. I'll look it up later.

GTR 02-06-2006 09:19 PM

Typical OBD II Drive Cycle consists includes of a cold engine warm up, accelerating to 55 mph 1/2 throttle, cruise 55 mph for 3 minutes, decelerate to 35 mph, accelerating to 55 mph 1/3 throttle, cruise 55 mph for 5 minutes - end of ODBII drive cycle. In a perfect world, all the monitors will be complete but lots of people know it takes a few good trips to get them all complete. Usually you will complete O2 Sensor, O2 Heater, and EGR System. The harder ones are Cataylst and Evap System.

Hope that helped.

MazdaManiac 02-06-2006 09:25 PM

^^ Excellent. Thanks!


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