Downpipe elbow question??

nofx230

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Jan 24, 2012
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i have a tanabe downpipe and my question is i still have the stock turbo elbow on it and need to install a wide band kit! I thought about getting one of those turbo elbows with the bung pre welded in it, but isn't that bung for the wideband to close or in the wrong spot? or should i just buy another down pipe with a built in turbo elbow like the BIC pipes and have them put in the wide band bung when i order it???
 

toyotanos

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The general consensus that I've come to understand is that for every inch of downpipe diameter, the wideband should be 1 foot away from the beginning of said downpipe. (i.e. 3" pipe should have a wideband 3 feet away from the turbo exit)

This isn't set in stone and you have some wiggle room, but the risk is that if the wideband is too close to the turbo exit it can get too hot and fail to operate properly. When I had the ct26 on my car, I tried the bung that came with the downpipe, and it worked, but it freaked me out that I might damage the engine if I didn't get it to where it should be. I now have the wideband lower, about where the the transmission and engine meet. Angle of the wideband is also something that needs to be though of- have the wires coming out vertically, otherwise water can collect and corrode the sensor.

lots of info, hope some of it helps!
 

nofx230

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the distance you noted makes sense, but what don't make sense is why companies put the bung so close to the turbo, most iv seen are bout 1 foot away!? also you stated that the angle is important iv heard that it should be put at the 10 0'cock position, is that bout correct from what your stated looks like I'm buying a new down pipe here soon
 

toyotanos

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Yep, lots of companies don't care, they are just making a part. Some people have luck running widebands close like that, but I would never do it if I had the choice. You can cut a hole into your downpipe and have a shop weld a bung in, that's just fine. 10-12-2 is a good area to stick around.

If you're sticking with the ct-26 for a while and want a new downpipe, I might suggest the bellmouth type downpipe. something like this: http://www.ebay.com/itm/7MGTE-Turbo...Parts_Accessories&vxp=mtr&hash=item25668ae312 just shop around places like driftmotion/ebay/etc for a good price and good reviews!
 

nofx230

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the reason i want to get a new down pipe is mainly cuz the tanabe pipe i have has a cat about 1 foot down the pipe it came on the car when i bought it this is going to sound crazy but would you recommend punching out the cat and then installing the bung for the wideband downstream of that?? like would that work or would i get a mixed reading from the sensor?? it can't be as bad as putting a wideband in one of those turbo elbows they sell where the bung is like 4-6 inches from the turbo any help or advice would be great
 

nofx230

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18 inches is fine but I'm wondering if I punch out the cat on my tanabe downpipe and mount it 18inches downstream if you think it will be ok Cuz I know it has to be before a cat but if I delete the cat seeing its bout 10" from the turbo I should get a clear signal to the wide band right??
 

toyotanos

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You are correct, you want a pre-catalytic converter position for the wideband, if you completely knock out the OEM pre-cat you'll be fine, but don't place it behind any cats.
 

toyotanos

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First iteration:
p1798475_1.jpg


Later iteration:
p1798475_2.jpg
 

Suprapowaz!(2)

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Pointing to the trans or away? Where did you send the wire harness through. I'm about to install mine here soon. I was thinking horizontal pointing away from the trans, and sending the harness through the body plug underneath the passenger floor. I'd run the harness under the carpet and up behind the dash somewhere. Bad thing about that is passengers would be stepping on the wire harness.
 

toyotanos

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I had mine angled slightly toward the trans (~10:30-11 o'clock). As for the harness, I tucked it behind the speedo cable shield to help ward the wires from heat and zip-tied it there for security.

My gauge is where the ashtray once was, so all the wires run through the engine wiring harness grommet.
p1798479_1.jpg



Edit: yep, I welded it in place there- it has a lot of clearance when you are down there, it just looks scary when its not in the car.
 

ForcedTorque

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I ran my wiring up through the shifter hole. It comes through, and can be run into the dash behind the radio bezel. That way, no passengers will ever get close to it. The car has never seen the road, and the wideband has been sold off, so I'll never know just how good that would have worked.
 

toyotanos

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I agree with that, but never understood why they were able to do so. I know the cats affect the way post-cat oxygen sensors respond, but didn't know how that could affect tuning the car using exhaust tip sampling.

I didn't have any catalytic converters so it made no difference where the sample came from on my car, just a little delayed. I just tried to try to get the cleanest/unalterated exhaust sample for the sensor possible, but there's another way to think about it? Please enlighten!
 

nofx230

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checked the car today and the down pipe has a bubble in it, i thought it was a cat but nope just a bubble lie an expansion chamber and theres a pre welded bung 18 inches down the pipe again i just bought this car so not certain whats going on with it
 

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IJ.

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jetjock;1798689 said:
To say flat out don't do it (at least for AFR measurement) is misleading. For example where do most dyno shops put a WB when tuning?
We've had this discussion here ;)

I'd like to do some tests with 2x WB02's one post and one pre cat just out of curiosity!