ok, so i am getting a dump pipe for the exhaust because i just spent $350 on the 3" downpipe, $50 for a 3" test pipe, and need to buy 2 universal mufflers. i can't afford a full 3" exhaust, so i'm running the dump before the cat and when not dumped, the exhaust will exit via the oem pipes and 2 new mufflers (maybe titanium).
so the boosted exhaust will be running through a 3" downpipe and directly out of the car before going through the cat. the dilemma is which dump to go with. for those who arent familiar:

1-the Qtec is electronically activated via a switch in the cabin whenever you want the exhaust to utilize the dump. it costs roughly $200.

2-the ATP VES is mechanically activated via a wastegate set to open the valve in the presence of 1psi or greater boost pressure from a hose running from the valve under the car to the intake manifold vacuum source. it costs about $50 more than the qtec.

i've gone over all the advantages and disadvantages in my head and it seems that the ability to turn off the qtec whenever you want far outweighs the slight inconvenince of turning it on when running hard. i mean, i know when i pull out of the driveway if im in the mood to run the car hard and deal with the sound of a 3" dumped exhaust with not cat, resonators or mufflers to quiet it down.

are there any aspects of these 2 that i may be forgetting, because i'm leaning towards the qtec right now. i will take audio/video clips of whichever i choose if someone can host them. but i must choose one ASAP because im now running the car through a 3" downpipe right into the brick wall that is the oem cat, 2.25 inch flange and twisted/probably clogged stock pipes.

one last thing...if i run the dump before the cat, is the PCM going to throw a CEL when the dump is opened because the rear o2 is no longer getting a strong reading from the gas that has supposedly (it thinks) gone through a cat? there will still be some gases running past the rear o2 sensor with the dump open correct? enough to keep the PCM happy? if not, can i just move the rear o2 up into the downpipe, or will i need to just install the dump after the cat and deal with the restriction? (keep in mind, i should be at 10psi+ from here on...no more 5psi bullshit, the HRC FMIC is going on in 2 weeks).

qtec is a modified motor from a coke vending machine. They burn out quicker than youd want. look into http://www.mccordcg.com/mpp/mpp.htm theyre cheaper (not in quality) and are steel rather than the qtec's aluminum, and have a built in override circuit to cut the signal from the switch when the plate is open completely, to help not burn out the motor.

thanks for the heads up, will look at that and start reevaluating my options

btw, my buddys been running the same MCPP for over 1.5yrs on his rx-7. With as hot as rotary exhausts get, that shows the durability of MCPP. and he opens it daily, motor is still solid as ever

if the qtec valve stops working for any reason qtec will replace it, i havent had any problems with mine though.

I personally would rather have the one that open with the onset of boost. Its just cooler.

Originally posted by turbo8u
if the qtec valve stops working for any reason qtec will replace it, i havent had any problems with mine though.

which involves removing your cutout and sending it to them, and waiting. MCC will do the same, except theirs wont break every 5 times you open it

Originally posted by SILVERNT

Originally posted by turbo8u if the qtec valve stops working for any reason qtec will replace it, i havent had any problems with mine though.

which involves removing your cutout and sending it to them, and waiting. MCC will do the same, except theirs wont break every 5 times you open it

whos to say the qtec breaks every 5 times you open it?...:wary...you? you dont have one, so you dont know :thumbsup

like i said mine still works perfect and its been used for like 7 months

Originally posted by turbo8u

Originally posted by SILVERNT

Originally posted by turbo8u if the qtec valve stops working for any reason qtec will replace it, i havent had any problems with mine though.

which involves removing your cutout and sending it to them, and waiting. MCC will do the same, except theirs wont break every 5 times you open it

whos to say the qtec breaks every 5 times you open it?...:wary...you? you dont have one, so you dont know :thumbsup like i said mine still works perfect and its been used for like 7 months

ask nate

Originally posted by SILVERNT

Originally posted by turbo8u

Originally posted by SILVERNT

Originally posted by turbo8u if the qtec valve stops working for any reason qtec will replace it, i havent had any problems with mine though.

which involves removing your cutout and sending it to them, and waiting. MCC will do the same, except theirs wont break every 5 times you open it

whos to say the qtec breaks every 5 times you open it?...:wary...you? you dont have one, so you dont know :thumbsup like i said mine still works perfect and its been used for like 7 months

ask nate

im going off personal experience, not hearsay. whoever this nate guy is, he likely bottomed out on it and thats why its not working anymore.

I think it's a matter of preference; both brands have pos./negs. I personally have been using the QTEC for about 2.5 yrs and never experienced any problem (driven 6-7 days a week, year round).

....and QTEC it is. Why? Because Josh is my buddy and what he says, goes.

well does anyone know about the rear o2 sensor issue (or non-issue) i mentioned

I brought this discussion up a few months ago because I was also curious. The answer is, it will not be a problem. Why? Because even though the exhaust gas is getting diverted to the cutout, some exhaust gas will still make it through the system. Enough will make it through to register in the rear o2. For assurance, my rear o2 has been off for a couple of months now and the only drawback is sucky gas mileage.

Is there still disagreement as to the use of a resistor inline with the secondary O2 sensor. Last time I heard it discussed it got dropped without resolution.

i'm just not clear on the rear o2's task...is it checking for a catalyzed exhaust or not? if it's not we should be able to just install the sensor further up on the pipe before the cat

The after-cat O2 sensor checks the voltage against the O2 sensor upstream to verify a voltage drop, ~.7-.9v drop, and checks to make sure that the voltage is fluctuating as well. If you put it before the cat, or took the cat out, the voltages would be about the same and the ECU calls a CEL on the whole O2 sensor system. The ECU won't know which sensors wrong, cause it doesn't care, it just knows SOMETHING is wrong. I believe that the resistor mod should work, it works on paper, but I haven't gotten rid of the cat yet so I haven't needed to do it.

i have the qtec before the second 02 sensor and obviously no cat...ive never had any CEL pertaining to the 02 sensors and i dont have the resistor mod for the rear 02

my car likes open dump, lol

Originally posted by turbo8u
i have the qtec before the second 02 sensor and obviously no cat...ive never had any CEL pertaining to the 02 sensors and i dont have the resistor mod for the rear 02 my car likes open dump, lol

interesting, how often is the dump open? If it were open all the time it might create a situation where you lost enough of the hydrocarbons to make the O2 sensor read correctly, but doubtful. Is it possible you're rear O2 sensor is caked in carbon, I think it was Dino who found that his O2 sensor didn't kick a CEL because it was covered in carbon buildup. Or maybe for some reason your car really does love you and it's just not triggering a CEL!

Originally posted by Keith2172

Originally posted by turbo8u i have the qtec before the second 02 sensor and obviously no cat...ive never had any CEL pertaining to the 02 sensors and i dont have the resistor mod for the rear 02 my car likes open dump, lol

interesting, how often is the dump open? If it were open all the time it might create a situation where you lost enough of the hydrocarbons to make the O2 sensor read correctly, but doubtful. Is it possible you're rear O2 sensor is caked in carbon, I think it was Dino who found that his O2 sensor didn't kick a CEL because it was covered in carbon buildup. Or maybe for some reason your car really does love you and it's just not triggering a CEL!

yea i remember dino saying his rear was caked in carbon buildup, lol im pretty sure mine is caked too...or like you said, my car really does love me :P

i only have it open when im WOT from 4500-redline because thats when you really feel the power gain, the low end loses a LOT if you're open before in full boost. thats just what ive noticed anyway, i dont use it much because i keep getting in trouble lol...brbububbbvurrmmmRAAAAHHHHH!!! PSHHHH!!!! ...cops dont like my car anymore