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Discussion Starter #1 (Edited)
Finally took the plunge and ordered and installed some RV6 High flow pre-cats. I was considering the pre-cat deletes for the longest time but after some research I decided the High flows were the best option, especially considering I had already hollowed out my third cat. The deletes from my research seemed to get a lot of rasp especially with the third cat deleted, while they do make more peak hp a few dynos show High flow actually make more average hp and TQ. I would be combining the HFPC's with the RV6 J-pipe that I had already installed. I am very please with the quality of the pre-cats and the hp/tq results, same goes with the previously installed j-pipe. The truck pulls so much harder all the way from idle to red line, I felt an instant difference pulling out of my drive way. The exhaust has a bit more rumble when getting on it but still very quite at idle and while cruising, which is exactly what I was after. I'm figuring with the j-pipe and HFPC's i've picked up close to 30-35whp and about the same in tq.

Total install time from start to finish with tools put away was 3 hrs. It went incredibly smooth almost to smooth. I did not remove the pass side axle as the owners manual suggests for the rear pre-cat. I simple removed the factory heat shield and removed the factory pre-cat from the pass side wheel well. It is much much easier this way IMO even if just replacing with a factory unit I would still do it this way. Also I should add that I live in FL and do not have to deal with rust issues which if you live in the rust belt I'm sure this job would be much much harder. I have also had my j-pipe off recently and also replaced all 4 o2 sensors recently, being familiar with both of those jobs made this job much easier as well.

Heres a link to my j-pipe post. Its post #180
http://www.ridgelineownersclub.com/forums/showthread.php?t=46221&page=18

A link to the RV6 website. Keep in mind only the 06-08 currently have a j-pipe available, 09+ there currently is no j-pipe for them.
https://rv6-p.com/ridgeline.html

A few links to dynos and hp/tq claims of HFPC's.
http://www.driveaccord.net/forums/225-performance/236954-rv6-precat-deletes-highflow-precats-header-options-now-available-3-5l-v6.html

http://www.driveaccord.net/forums/225-performance/240361-dyno-results-rv6-pcds-vs-rv6-hfpc.html

Yes those dynos are not on an RL so yes hp and tq gains will be slightly different. Yes most dyno's of HFPC's mostly only go from 3,000 rpm and up, Yes the biggest gains are on the top end, but I can assure you low end tq is also improved greatly. I noticed and instant difference down low with just the j-pipe and even better when combined the HFPC's. The truck just pulls like a beast now from idle to redline, takes very little throttle while cruising to pick up speed, don't have to force a downshift to get this beast moving anymore.

I don't have a complete list of tools or pics of every single step I took but I did the best I could as I know there are not any threads with any great detail of this mod or removing/installing factory pre-cats. The rear cat is very hard to see and get pics of so I did the best I could.

Your main tools you will need are 10, 12,13, 14mm sockets short and long sockets will be needed. A couple different size extension's, an o2 sensor socket, flat head screw driver, Jack, jack stands, socket to remove wheels(I don't have facory wheels/lugs so I don't know what size most will need) torque wrench and I think that is about it.

Anyways on to the install and pics!

The pre-cats from RV6








I decided to paint them silver with some 2000 degree spray paint. The cat itself is made of stainless but was not sure about the rest so I added some protection from the elements with high temp paint. You can get them coated for another $80 and it takes another 2 weeks to get them as they have to be sent out to be coated.



First remove the engine cover.

Remove j-pipe. That is the RV6 J-pipe.


Remove fan.


Removing o2 sensors and center spark plug coil. I only completely removed the top o2 sensors, the bottom sensors I removed from pre-cat and let them dangle at the bottom, removing all the little clips on those o2 sensors are a pain in the a** and can easily add another hr to the install.


Remove front pre-cat.




Install RV6 pre-cat and o2 sensors. Do not tighten pre-cat all the way yet, just leave it loose for now. Pic show it tightened all the way down but don't do that just yet.


Thats it for the front!

The rear goes about the same except for the actual removal of the pre-cat. Everything on the rear cat is done by laying over the top of the engine and doing it by feel rather than sight, makes it a bit more difficult but its not to bad.

Remove o2 sensors, remove all the nuts holding the pre-cat at the head, remove factory support bracket, remove pass side wheel, remove factory heat shield around pre-cat(wheel needs to come off first to get one of the bolts), remove guard around axle(sorry no pics of this item but you will see it when you are in there. The guard is held on by 3 bolts and it must be removed in order to get the pre-cat out.

Now you can slide the pre-cat out. This a bit tight but its really not bad. I would suggest putting something around your axle boot to keep from hitting or tearing it. Mine is actually already torn(you can probably see all the grease in some of the pics) so I did't really care about it. Its the next thing to get replaced but since I knew I was doing this I wanted to wait until the pre-cats where done so I did't have to risk tearing a new boot.




Both pre-cats are now removed. As you can see these are just as bad a design as the factory j-pipe is as far as flow goes. What you can't see is at the bottom of the rear cat(one without the shield) it has a big indention from the factory restricting flow even more.


Rear pre-cat being installed.




Rear Pre-cat lined up and loosly fitted.


Time to put the J-pipe back on.




Once the j-pipe is lined up you can tighten all the nuts at the j-pipe to the bottom flange of pre-cats, then tighten all the nuts at the pre-cat to head(remember we left them loose when we installed them earlier, this is why it makes it much easier to line up the j-pipe), then tighten the j-pipe to third cat. Then you can reinstall the fan and double check all your nuts bolts, wires, o2 sensors, and your done!

All that's left to do is take if for a test drive and get it good and warmed up, let it cool after the drive and recheck all your nuts and bolts to be sure they are good and tight.

Hopefully this will help anyone else looking to do this mod or anyone just looking to replace a faulty factory pre-cat. This really was not a bad job, like I said earlier it only took 3 hrs start to finish. I know I took more than 3 hrs last week to changing oil/filter, trans fluid, transfer fluid, brake fluid, power steering fluid, air filter, cabin filter.
 

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Great pics and write up.

I am wondering how this type of mod would be received during the periodic emissions checks that we have in MD? They look for codes and take a quick glance under the truck with a mirror. My guess is that they would never notice.

That said, I presume they (J pipe and high flows) are not technically legal? Would emissions at the tail pipe be significantly higher?

Thanks!
 

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Great question..it is unlikely they would see anything different except it looks "too new"..but that is easy to fix.

The numbers is where it's at. If you don't have periodic measurements in your state/county you don't sweat it. If you do, a workaround could be another thorn
in your side.
I think the limits are quite wide, even in CA. You need to have a noticeable issue
to fail. I think an engine in close to perfect running condition, no oil burning, smooth idle, fully warmed up would pass with high flow CATS. Might be on the lower end but still to spec.
I think the ones they usually catch are those with either a chronic engine issue like a burnt valve, or an engine with too many miles that is marginally dirty just from wear. Those CATS might be enough to tip the scales to the negative side.

I think most mechanics can run a pre-test to see if it is clean. You may have to conjure up a reason you want the test.
 

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2006 Ridgeline RTS in Steel Blue
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Man, I know you've changed out wheels and such, but I'd love to see a 4 wheel Dyno on this setup. Any other long term plans?

Really nice write up and looking like a really sharp looking truck.
 

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Discussion Starter #5
Great pics and write up.

I am wondering how this type of mod would be received during the periodic emissions checks that we have in MD? They look for codes and take a quick glance under the truck with a mirror. My guess is that they would never notice.

That said, I presume they (J pipe and high flows) are not technically legal? Would emissions at the tail pipe be significantly higher?

Thanks!

This is a tough question to answer and I don't have a exact or perfect answer for your state or situation. I do not have any emissions testing if FL so I don't worry to much about it. Technically you are correct they would not be legal. If all you have is a visual and code check I really don't see these mods as being an issue at all. I have not had any codes since install, funny thing is I actually had a ongoing p0420 code prior to install. It was really part of my justification for doing the mod in the first place. Only thing I would do different if I had a visual check is not paint the pre-cats. If you leave them without a coating they will tarnish just like my RV6 J-pipe did and no one would know the difference.


Great question..it is unlikely they would see anything different except it looks "too new"..but that is easy to fix.

The numbers is where it's at. If you don't have periodic measurements in your state/county you don't sweat it. If you do, a workaround could be another thorn
in your side.
I think the limits are quite wide, even in CA. You need to have a noticeable issue
to fail. I think an engine in close to perfect running condition, no oil burning, smooth idle, fully warmed up would pass with high flow CATS. Might be on the lower end but still to spec.
I think the ones they usually catch are those with either a chronic engine issue like a burnt valve, or an engine with too many miles that is marginally dirty just from wear. Those CATS might be enough to tip the scales to the negative side.

I think most mechanics can run a pre-test to see if it is clean. You may have to conjure up a reason you want the test.
Agreed. If you were to run the high flow pre-cats, j-pipe and third cat I really do think you would pass an emissions sniffer test and a visual. Another work around would be to try and work the factory heat shields back onto the RV6 cats, it is so tight down there I don't think any professional would even know the difference when doing a visual check.


Man, I know you've changed out wheels and such, but I'd love to see a 4 wheel Dyno on this setup. Any other long term plans?

Really nice write up and looking like a really sharp looking truck.
I have no plans to put it on a dyno, while I know many might like to see dyno numbers it is not what I am after. This truck is not a race car and I'm not after max hp/tq numbers simply put I was after a little more pep in its step, which is exactly what I got. As far as future plans I don't have much left as far a performance, I go back and worth with adding a cat-back. I think with the high flow, j-pipe there is still some gains to be had with a better flowing cat-back but I really don't want the sound or cost vs gain that comes with one. I am looking at possibly adding a roof rack and some running boards.

Thanks for the compliments. Not sure if you've seen my transformation thread but its got some pics of my truck along its journey to what it is now. I really do need to get some new pics taken as there have been a few changes since the last pics in this thread.
http://www.ridgelineownersclub.com/forums/showthread.php?t=99129
 

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Discussion Starter #6 (Edited)
Just thought I'd throw an update in.

I wanted to get rid of my hollowed out third cat as it seemed to be making some turbulence noise. Its hard to describe but it made some weird clattering noise on start up for about 20 sec or so till the pipes warmed up, it also gave off a deep throaty rattle on acceleration.

So I added a Megan racing resonated test pipe. Its has seemed to solve both issues the clattering start up and the throaty rattle on acceleration. I don't know if I'll be keeping it as the inlet outlet size is a bit small at about 2 1/8, if I had know the size prior to buying I probably would not have bought it. That size would be fine on a stock setup but the RV6 j-pipe outlet at 2 1/2 and now i'm thinking of adding a cat back that will be 2 1/2 which would make this test pipe the weakest link. I've done a bit more searching and have come across some other test pipes that are 2 1/2 but they are pricey at $125 this one was only $70 shipped.

 
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