Failed emissions test…

[firewalk]

I have an MR2 Turbo which have been heavily modified.

Topic

[college man]

incomplete combustion. start by cutting your fuel
curve back. you need to lean the car out. you may
need to adjust timing. actually I don’t think a lower
grade fuel will help you here. probably will make things
worse.

[firewalk]

Quoted From college man:

incomplete combustion. start by cutting your fuel
curve back. you need to lean the car out. you may
need to adjust timing. actually I don’t think a lower
grade fuel will help you here. probably will make things
worse.

I’ve tried to lean it out, but the engine will barely run. I guess it’s partly because I have 720cc injectors, and at low idle they have a very low duty cycle making idle rough. The less fuel at idle the rougher the idle becomes. That, combined with the overlaping 264 cams makes things quite difficult :
I had hoped that since E85 needs about 30% more fuel I could somehow overcome the duty cycle problem and at the same time perhaps score some since alcohol burns cleaner than gasoline?

Anyone know if it is even possible to pass with a HKS 264 cam? (on a MR2 mk2 Turbo)

[moparfan]

idk of a real way to do it for sure other then put it back to stock or go buy your self a stock engine to drop in it everytime you need to pass the test. other wise i can’t help ya my friend. this is the very reason i stick to the states without emission tests haha i don’t have any vehicle that would pass!

[firewalk]

Quoted From moparfan:

idk of a real way to do it for sure other then put it back to stock or go buy your self a stock engine to drop in it everytime you need to pass the test. other wise i can’t help ya my friend. this is the very reason i stick to the states without emission tests haha i don’t have any vehicle that would pass!

Those darn environmentalists! Hehe..
I live in Norway and over here they just put the sniffer into the pipe at idle, no dyno run and TEC2 hookup at the same time, so I guess it’s somewhat more of a hassle over there in some of the states.

However, there should be ways to overcome this problem without having to change the engine every time I have to get this test!

A friend of mine has a 300zx with 850cc injectors! And he managed to pass! How difficult could it be? 😉

BTW:

I just spoke to a friend of mine who works at a honda dealer. I’m going there tomorow to hook up the emission testing equipment, and hopefuly I will manage to tune the engine somewhat in the right direction.

Do anyone have any suggestions to making it burn cleaner? I guess BTDC ignition should be about 10 degrees on this 3S-GTE engine. Is there any gains from lowering/increasing ignition ? I’m going to lean out the mixture drastically to try to get it under the limit. Also resetting the cams to stock (0) should help. Right now the exhaust cam is retarded about 7 degrees, and the intake cam is advaned about 4 degrees.

This engine performed about 420 hp on a dyno last time I checked. I’d hate to spend severel weeks putting it back to stock.. Then back to the way it was again. I’d rather bribe the whole staff to just let it get trough then! Just the very thought of the amount of work needed makes me sick..

Gonna try to lean it out so much it reads about 14,7 – 15 AFR. That should help. And perhaps get some E85 on the tank if that won’t help.. This should turn out to be a rather interesting experiment, seeing if the E85 makes any difference. 🙂

I have a high flow catalytic converter on it now. Would adding a second converter closer to the exhaust manifold make much difference?

[college man]

Adding another cat won’t do anything. can you install the
factory chip? your not using a programmer? Your car is on
steroids. you need to get it off the juice.

[firewalk]

The steroids thing made me think. Why not just starve it of steroids? So i went to a friend of mine who works at a Honda dealer (how about that?). They have a testing mashine.

Here’s what I did:

1. I have adjustable cam gears. Exhaust cam was retarded 9 degrees. Intake cam was advanced 4 degrees, thus creating lots of overlap. I placed both cams in the 0 position (stright up). By doing this I have eliminated as much overlap as I can.

2. I added 5 liters of ethanol to the tank (had about 20 liters of gas in it)

3. Hooked up the emission testing-mashine and started to adjust the ignition and fuel tables. I realise that owners with stock car’s won’t be able to do this in this maner, but manipulating fuel and ignition should still be possible to some degree though.

So what I ended up with was a BTDC Ignition of 10 degrees at Idle speed of 1050 RPM. I leaned out the fuel mixture by lowering the injectors pulsewidth to about 0,98 MS (I have 720cc Injectors).

This gave me a Air Fuel ratio that jumped up and down somewhat between 15 and 17,8 (quite lean) but according to the mashine I should pass the test with theese settings!
AFR;

Mashine readout:

[EricTheCarGuy]

I was going to suggest that probably the only thing you could do is to change the fuel map but adjusting the cam timing in addition to that is brilliant, I think the only problem you might run into is your idle speed, see if you can get it below 1000rpm and I think you’re in the clear because those numbers are looking VERY good IF they are going to do a tailpipe emissions test, if they do an emissions monitor test your modded computer may show up and blow the test but if your MR2 is pre 1996 I don’t think it will be an issue because I believe they would do a tailpipe test for vehicles older than 96. Keep us posted on how it turns out.

[EricTheCarGuy]

Well done on passing the test, to be honest I’m not sure if that would work or not but I’d love to know if it did so when you find out please come back and let us know.

[firewalk]

Quoted From EricTheCarGuy:

I was going to suggest that probably the only thing you could do is to change the fuel map but adjusting the cam timing in addition to that is brilliant, I think the only problem you might run into is your idle speed, see if you can get it below 1000rpm and I think you’re in the clear because those numbers are looking VERY good IF they are going to do a tailpipe emissions test, if they do an emissions monitor test your modded computer may show up and blow the test but if your MR2 is pre 1996 I don’t think it will be an issue because I believe they would do a tailpipe test for vehicles older than 96. Keep us posted on how it turns out.

I set the idle speed to 1000 rpm And retarded the timing a bit to make it sound less modified. It passed the emissions test. This time it was 0,01% CO. They didn’t really belleive it so they actually had to test it twise to be sure.

But they said it’s too loud. I have a TKO exhaust from KO racing. 2,5″. I have the 7″ silencers which are supposed to be the most quiet available for this exhaust system.

How can I lower the noise? I’ve red about “plug” silencers that you fasten in the tailpipe itself. And they are supposed to make it quieter. Do theese really work?
I’d rather not have to change the entire exhaust. It wasn’t much to loud, just a tiny bit.. So whatever I can do to make it quieter.. Any thoughts?

I found this on ebay, would such a thing actually work? : http://cgi.ebay.com/ws/eBayISAPI.dll?Vi … vi-content

[college man]

Glad to hear you passed emissions. You might want
to right down all the settings that got changed for the
next time. The only way to quiet the exhaust is to either
put different mufflers on. or you try putting steel wool either
in front of the mufflers or somewhere in the pipe. If the system
is flanged. put it at a flanged area so you can get it back out.
roll the steel wool in this mesh. crimp or wire the outlet side closed.
insert the mesh with the steel wool in the pipe. now you just made a
noise suppressor. when done take it out. you should be able to get this
at any home center.

http://www.plumbersurplus.com/Prod/Mat- … 3031303335

[Author]

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