I am a happy new owner of a 99 2.2 Vtec lude (AT).
I wont be planning big modifications, just the basic.
I would like to remove the entire exhaust system (including the cat) and replace. With some custom 2.25" pipe and 1 muffler at the mid and 1 at the end.
I wouldn't mind a header too, but factory ones (mungen) are not realy available here (in Hungary= cheap *** country=no serious tunning culture) and I dont think anyone here can custom design those.
My question is:
As I understand removing the cat would cause a problem, as the 02 sensors (if i got it right) would let the ECU know that something is wrong.
I understand that there are "dummy" 02 sensors available for just this purpose. There will be no ECU (eg: VAFC) mods! So if I change the pipe and install a dummy 02 sensor, will that be fine? Does the dummy send a fix fake constant data to the ECU or does it vary at random? If yes does the variation have any effect?
Basically I am asking if its ok, to remove the cat and install an 02 sensor with no ECU mods/dyno/VAFC tunning?
I was also planning on a direct air filter, but my mechaninc said that hondas are very fine tunned with the resongator pipe on the air intake and replacing that might have a negetive effect. As for me adding a cold air intake would mean removing the stock resongator and putting on some random size pipe and then the filter, but i might be wrong.

P.S: I understand that this mod (cat removal), might have a negative effect at low revs and positive at high revs. If I am correct this is due to the lose in pressure/resistance with the cat gone, but that is why I am having a mid muffler (also to reduce sound).
What hp gains am I looking at with this, I understand stock is 195hp.

any input is welcome and thanks.
any suggetions are wellcome.

oalex

 

I had mines removed for a while, and I had the Secondary 02 Sensor Welded back into the straight pipe, it worked fine for me, but other people I know tried this and it threw the check engine light, so you may have to end up going with the 02 simulator for your secondary 02, but I'm not sure how well that will work, but its workable. As for intakes, such as the AEM Cold Air, it gains power over stock, at High end and some midrange, so it woulndt be a bad choice, unless it floods over there...

 

THX.

no flods here just your basic 4 seasons.

anyone else?

 

Little off topic but has anyone had any problems putting in a carsound high flow cat off of kteller.com? I'm planning on getting one but there are no size measurments or anything and all i know is to get the o2 sensor at the back of the cat. what are the gains from doing something like this and what would the gains be from a test pipe?

 

If you don't have any real mods on the engine why bother deleting the cat? It's not causing you any problems in power, I can guarantee you that. The only improvement will be the sound (if you can call it that... it'll just make your car sound like a noisy fart can) and the placebo effect in your mind. You'd have to opent he engine and do at least a couple more mods for deleting the cat to be worth your while. The gains w/o doing a nice custom exhaust/header, and IM P&P, cams, and a good CAI your gains will be in the 1whp range, that's it. There's too much restriction in the rest of the off the shelf/stock parts for a test pipe to help your power. Before anyone chimes in, back it up with a back to back dyno NOT from a manufacturer. Every single one that I've seen that's back to back yeilds nothing in a basically stock system.

 

now that is interesting. If its all true then I am not going to fulfill any of my above mentioned plans.
I was under the impresion that cat had about 8-10% restriction on out-put, but I heard that a long time ago.

Could someone plz back TimeRacer up, cause I am then going to save all this cash for a kick *** audio system (at least that part I am familiar with.

 

yes at the very most, you will be looking at a 1whp difference with/without a cat.

yes it is pointless to ditch the cat unless your motor is built, then i guess you can go for it.

If you want to stick with basics, go with an intake (or just a apexi power intake bad *** filter), a decent header something other than dc, and a nice exhaust as you were planning. If you arent going to do all 3, no point in getting exhaust.

 

thx guys.... I was under the impresion that the cat was a usless (except enviromantal vise) chock on the engine breathing, I tought it was up to something like 8%, but i guess I was informed wrong.
I will be replacing the stock air filter with K&N but I will be putting that in the stock system, no resognator tube replacment or direct system.
Header is a bigger deal, as I mentioned, it is not available in Hungary, I would have to buy is in another country (say Germany or Austria which are close), but I guess it would cost a lot, maybe even too much.
I might then leave the exhaust system intact and just replace the stock muffler and weld a sporty one. Ofcourse this would just be for sound, nothing too loud, just deep and sporty.

 

With the mods you planned keep the stock cat. Other than the fact that your car will be much quieter and not stink of sulfur you won't notice it's there.

 

ok, will do.
Thanks