Test pipe; whats your opinion?!

[talonation777]

Before I get into the details, I just want to say that I searched the forums for the last 30 mins and I was unable to find the answer to my questions.

Here we go....

I am thinking about getting a test pipe, a buddy of mine just bought a new N/T engine and it came with a test pipe connected to the downpipe. He said he'd let me have it for cheap. So I thought I'd look into it more. I know a little bit about them. I know its just an open pipe and frees up the exhaust flow better then the cat.

My car currently has DC sports headers, DC sports downpipe, Apex'i N1 catback (2.5" piping), an AEM short ram intake. The car is a daily driver, and I dont plan on taking it to the track. I have to worry about emissions, but I;m going to hold onto my stock cat and just swap it when I go for my test (assuming I go with the test pipe)

Now that you know my set up, I'm wondering if the test pipe will hurt me, or benefit me. I dont want to ruin the sound of my exhaust because it sounds awesome right now. I read many things about the tone becoming more raspy, but I never read about it on the Apex'i exhaust.

Please help me out in anyway, let me know your opinions. Thanks for the space!

 

[Locke]

Switching from a cat to a test pipe will make any exhaust more raspy that it originally was. The catalytic converter is the single largest restriction in the exhaust system, you will benefit from removing it. You can also purchase resonators that bolt in place of the cat, that aren't as loud or raspy as a test pipe, but will still be raspier that with the cat in place.

You will get a CEL unless you wire in an o2 simulator. VelocitàPaola sells these, if you want one. PM him, he is always looking for a sucker to make a quick buck from.





Just kidding, of course! I recommend purchasing from him.

 

[dsmclipse97]

yup Locke pretty much covered that... you just need to weigh the pro/cons of this. heres what locke was refering to by a resonator:

http://cgi.ebay.com/ebaymotors/NEW-95-02-Eclipse-bolt-on-Exhaust-Resonator-C116_W0QQcmdZViewItemQQcategoryZ33633QQihZ014QQitemZ330110716697QQrdZ1QQsspagenameZWDVW

they are pretty cheap but dont expect more than 5hp at the wheels, if that.

 

[totaleclipse_05]

I always read to keep the cat on our cars if they were NT. I should look up some more info on it.

 

[1.8laser90]

when i installed my header and resonator to take the cats place i noticed it got real slugish and would almost fall on its face between shifts for normal driving. When i installed my afx ecu this went away, between shifts it would go right back to accelerating instead of bogging down. Ive heard rumers on other cars that when they removed there cat this happend to them also. Now on my 1g when i removed the cat and installed the exhaust it made a world of a diference. my guess is some cars it has a + or a - effect on how it runs with there current mods. Now the reason i think the afx ecu helped the most is because it requires you to remove your cat, and it also doesnt read your downstream o2. I never had a check engine light the whole time without a cat, so my guess is it messed up my fuel mixture causeing it to run alittle rich ? just thought id throw some things out there

 

[dsmclipse97]

totaleclipse is right, the NA cars do need some backpressure. You can always go with a high-flow cat. Here is a cheap OBX one i found in a minute on ebay:

http://cgi.ebay.com/ebaymotors/OBX-HIGH-FLOW-CAT-CONVERTER-95-99-MITSUBISHI-ECLIPSE-NT_W0QQcmdZViewItemQQcategoryZ33629QQihZ006QQitemZ160107915839QQrdZ1QQsspagenameZWDVW

A little more expensive but you wont have a CEL you can pass emissions and you wont have a raspy exhaust note. wont give quite the gains of a test pipe but its an option worth considering...

 

[DSMcrazy3]

totaleclipse is right, the NA cars do need some backpressure. You can always go with a high-flow cat. Here is a cheap OBX one i found in a minute on ebay:

http://cgi.ebay.com/ebaymotors/OBX-HIGH-FLOW-CAT-CONVERTER-95-99-MITSUBISHI-ECLIPSE-NT_W0QQcmdZViewItemQQcategoryZ33629QQihZ006QQitemZ160107915839QQrdZ1QQsspagenameZWDVW

A little more expensive but you wont have a CEL you can pass emissions and you wont have a raspy exhaust note. wont give quite the gains of a test pipe but its an option worth considering...

Test pipe.

 

[Locke]

the NA cars do need some backpressure.

I disagree.

This, seems pretty accurate.
http://www.uucmotorwerks.com/html_product/sue462/backpressuretorquemyth.htm

 

[xceler8]

Unless your trying to flow as much air as possible to help spool a turbo up, I would say go against the testpipe and jsut get a high flow cat. I ran a testpipe for a little while and didn't notice really any benefit. I switched over to a random tech 3" hihg flow cat and actually felt abetter. Probably in my head though.

My setup is a mandrel custom 3" dp with flex section, going into a 3" random tech cat, then to a Apexi N-1 GST system that uses the larger diameter. It's huge! I still stand by the system like you do. I don't any codes obviously and it sounds good. ncie and deep, no raspy. I can't really hear my pipe inside the car cause my damn motor is so loud.

I say no testpipe. Some back pressure is good for n/a, you will reap more benefits from a testpipe if turbo.

My.02

 

[DSMcrazy3]

When I put a true High flow catylitic converter on my car in place of the old test pipe, I noticed a difference. Car felt more sluggish making its way through the powerband.

 

[BigRand]

If I were you, I would figure out what your trying to do.

If you throw on the test pipe from your friend, hopefully you won't be paying anything more than about $40, then I would go for it and take the time to swap it in and out for emissions.

I would say a highflow cat would be a good idea, if you don't like the sound of just the test pipe, and don't want to have to worry about swaping for emssions, but its obviously a little more pricey, and if your not racing, you have to ask yourself how worth it is it. (I would say its worth it because of the money you spent on the AEM intake, N1 exhaust, and DC sport headers)

2nd thing about highflow cats, DSMcrazy touched on this, but an OBX highflow cat, or anything else listed on ebay as a highflow cat that looks just like a pipe, is just that. a pipe. Don't buy into it thinking its gonna save you from emissons.

I have heard wonderful things about switching to a testpipe on a NA 420a, but have no expericne myself.

and last, in any car backpressure is always the enemy, please people, do read into the thread that locke posted, and understand its not backpressure NA cars are worried about keeping, its the scafeging effect (spelling..) that you must read up on. Don't be fooled.

 

[xceler8]

"The reason why the engine is burning lean to begin with is that the reduction in backpressure is causing more air to be drawn into the combustion chamber than before"

So if less backpressure makes you conbust more air, will our ecu correct for this? If it won't, then your going to be running leaner, which will as we all know increase power since motors make a little more power as you lean them out, but you then can risk the wear of running lean on your motor over time. So when you say you noticed a differene when you put a testpipe on, it's because your engine is running a little more air flow with the same fuel flow and thus is running a little leaner.

This could be me going too much into the article and pulling it apart.

Like rand said, if it's free or really cheap, take it, put it on, see how you like it. If you buy a cheap crappy high flow cat, you will get just that, cheap crappy results.

 

[bullettdsm]

Switching from a cat to a test pipe will make any exhaust more raspy that it originally was. The catalytic converter is the single largest restriction in the exhaust system, you will benefit from removing it. You can also purchase resonators that bolt in place of the cat, that aren't as loud or raspy as a test pipe, but will still be raspier that with the cat in place.

You will get a CEL unless you wire in an o2 simulator. VelocitàPaola sells these, if you want one. PM him, he is always looking for a sucker to make a quick buck from.





Just kidding, of course! I recommend purchasing from him.

X2.

E-bay hi- flow cat = resonator which pretty much = test pipe (just a little different sound). A real hi-flow will cost much more. I would (and did) choose the $30 hi-flow.

MB

 

[Locke]

"The reason why the engine is burning lean to begin with is that the reduction in backpressure is causing more air to be drawn into the combustion chamber than before"

So if less backpressure makes you conbust more air, will our ecu correct for this? If it won't, then your going to be running leaner, which will as we all know increase power since motors make a little more power as you lean them out, but you then can risk the wear of running lean on your motor over time. So when you say you noticed a differene when you put a testpipe on, it's because your engine is running a little more air flow with the same fuel flow and thus is running a little leaner.

This could be me going too much into the article and pulling it apart.

On modern vehicles, the ECU uses the o2 to try to keep the afr near stoich.