New exhaust finally getting done

[Snafu]

Within the next week or two I should have a new exhaust installed on the truck using Doug Thorley headers and a Nismo cat-back system. Both are nice and shiny to distract me!

The challenge will be to join the two using the existing cats (if re-usable) but the shop has the tools to make what's needed. Won't really know for sure until the truck is in the shop.

A lesser challenge is the cat-back is for an 03-04 frontier (short-box) and the slight differences with the 01. The only problem might be the rear hanger and possibly length. No much else is different from what I can see in the FSM.

Also thinking about replacing the rear O2 sensors...at 170k+ the old ones might be a bit tired.

Any suggestions on what O2 you used?

Thanks

[studum]

The length should be good, if a hanger needs modded they should be able to tack one on without issue.

Interesting you mentioned O2 sensors. They've been on the back of my mind for a while and I've been debating changing out my front O2's as well. I have 240+k now and I'm not sure that they've ever been done. I'll be paying attention to any advice here. If you end up finding a deal and ordering from the states let me know. Cheapest place I had found was Rock Auto...

[Snafu]

I'll be looking around to see what can be seen and looking for input from anyone else who has replaced them.

As long as you get the right type from a reputable name (ex. Bosch) then it may just be a matter of wiring it to the plug (if it's not a Nissan specific plug)

[the x kid]

Good luck. Can't wait to hear it later.

[Bender]

I'll be looking around to see what can be seen and looking for input from anyone else who has replaced them.

As long as you get the right type from a reputable name (ex. Bosch) then it may just be a matter of wiring it to the plug (if it's not a Nissan specific plug)

There is a bunch of companies that make o2 sensors, and when I worked at Nissan, had lot's of luck with Bosch and the like with definite plug and play capabilities. Might as well replace them while you are doing a front to back exhaust system.

I would bet you will need and be better off with new cats though. Even if they pass it will be just. Like the o2's, it would be a shame to not upgrade/replace cats while you are there. The cats may look good to go but ever try inhaling/exhaling through a straw?

[Snafu]

I will replace the cats eventually and who knows the guys at the shop just may say they are shot and need replacing now. I would replace the cats and O2 but the cats would be another $500 and not sure on the O2. After the headers, pipes, bits n pieces, I would like my wallet build up a little more equity. If it just passes the sniff test then I am cool with that cause we all not it is just a crock of crap

[Snafu]

The truck is in the shop this morning. Some gorgeous cars in there with nice work. Stuart and Carl sound like good guys.

[Bender]

The truck is in the shop this morning. Some gorgeous cars in there with nice work. Stuart and Carl sound like good guys.

You must have taken it in to Coachworks?

[Snafu]

Yes. Coachworks in Milton. Mike recommended them because the parts are not direct bolt-on and would likely require some modifications.

I have not looked underneath yet to see the work (dang work always interferes with fun!) but will this weekend.

As it turns out, although the headers are designed for the truck (by the guy at RockAuto) the cat and pipes needed some modifications to fit the headers correctly. They didn't say what mods the cat-back might have needed but I suspect one hanger had to be adjusted.

Another point to mention about the headers, is the air pump connection on the driver side (on top of the headers). There is connection on the stock truck (at least not on mine). The bung/connection needs to be plugged up. We never thought to look at it more closely before I left the shop and at 5 they realised they didn't have the right plug to close the hole. I suggested welding a washer over the bung in hopes of cutting it off in future and replace it with a proper plug.

If you go with the Doug Thorley headers then make sure the truck connects to manifold or you have a proper size plug so you don't have to weld it up.

I did notice that the tailpipe is hot as Hades. I could not keep my hand on it after driving home. Never noticed it being this hot before. Hmmmm.

In the end the truck definitely does not leak exhaust fumes and it is a bit quieter. It does have a nice sound.

Thanks!

[the x kid]

Wait!What about power? Is there more power?HP or Torq, either or.

[Snafu]

I wasn't going in to get power gains but it does seem to be a little more bottom end. Of course with the old exhaust I was taking it easy.

[studum]

Funny you mention bottom end. I thought I saw a gain in the top end. But I only did the Nismo exhaust, no headers or cats so there's a pretty big difference.

I like the sound of the Nismo too. It's there, but it's not stupid. I bet with the headers it sounds even better.

Do you only have 1 pair of cats? Or 2 pairs?

[Snafu]

I really have not had much of a chance to try it out. When I picked it up I had a tired kid in the back falling asleep and I was trying to avoid bouncing my way through Milton (some roads are horrible).

The goal was to replace the exhaust with something better than the stock bits and hopefully stay emission compliant. If there are power gains (and I bet there are) then it is a bonus.

My truck came with 2 cats and 2 pre-cats. The pre-cats at the front had to be eliminated. The headers are roughly the length of the manifold and pre-cats. They were able to re-use the stock cats.

Oh, and the check engine light eliminators had to be used. There was interference if the O2 sensors were left on the cats. I told the guys at the shop to take measurements in case they wanted to make these for themselves.

[studum]

Are you sure the front cats are pre-cats? I thought the front cats were the main cats based, on the older trucks that only have 2 cats, their cats are where our front ones are located. They have a straight "b-pipe" where our second cats are. Some have even swapped these cat-less pipes in for the secondary cats without issue.

[Snafu]

Pretty sure. They are a coarser mesh to pre-clean and are smaller than the primary cats (rear set). From the FSM for the 01 and 04 trucks they show the rear cats with minor variations. None show the rear cats not being present.

I cannot locate a diagram with the pre-cats in the FSM. Just the manifold then the rear cats. By the FSM you would not think they were present and the rear cat would bolt straight to the manifold.

[studum]

Wow, talk about mixed signals. Then check courtesyparts...

They only show the front cat in the "Catalyst Converter" section, no mention of the rears at all.

http://www.courtesyparts.com/frontier-p ... _2156.html


Then I found the rear cat in the exhaust section. The second cat is called nothing more than "exhaust tube assembly". Obviously there's a cat in it though...
http://www.courtesyparts.com/frontier-p ... _2155.html


Not trying to cause an arguement or anything, just trying to make sure you know what you have when it comes to e-test time if it happens to not pass. Also, the thought had crossed my mind to install the catless b-pipes, but if they're the main cats I don't want to even think about it. Obviously I have bigger issues right now though (see transmission post )

[Snafu]

No worries That lower pic looks like it is from the FSM (excluding the part numbers).

Been discussed with Mike and others in the club who have done this. So far only Jayman had troubles with emissions but he also used high flow cats...others may not have had e-tests done yet but even if fails you can get conditional passes.

The guys at the exhaust shop noted that there are cheap cats out there and you may pass one e-test. They are now carrying only cats with HM code (heavy metals) that have more heavy metals in the cats and should be good for two e-tests (probably depends on amount/type of driving and engine - they do performance stuff too).

Hopefully your tranny issue is resolved or much improved.

Thanks for the concern!

[studum]

^^^ Yep, you've definitely done more research than me

[Snafu]

lol...when doing a big job on the truck I like to be somewhat sure before going ahead.

I am going to drive the truck to work tomorrow and see how it does - 130km round trip through halton hell.

[Morpheus]

The first cats in line will be "pre-cats" because they come first, regardless of how much work they do as opposed to "post-cats"

I also had a conversation with Steve at rugged rocks, and he also told me that, with the odd exception, he hasn't had any customers with e-test failure problems.

I still haven't got my check engine light eliminators installed yet, so my truck is running really rich still.