So about a week ago I started hearing a minor exhaust leak between 1500-2500 rpms. Last night I had the car in the air, ready to get under it and figure out where it was coming from, when work called and I had a support issue to deal with.

Damn, no time.

So i get up this morning to drive to work, and i'm going under a bridge on the freeway and just hear this loud thunk. Got a flashlight at work and looked around.

Here's what's left of my rear PCD, trololol:






As you can see it wasn't a weld issue (i have the latest and greatest from Richie).

I'm convinced this is the long-term effects of the 3.7 throttlebody. Back when I installed it, I noticed right away there was jerking whenever I let off the gas pedal, and if giving it just a hair of throttle to maintain speed, in low gear sometimes it would jerk violently (only way to get it to stop would be to depress the clutch) which I noticed mostly in rush hour when i'm mainly in 1st and 2nd.

When I was still doing dyno comparisons, I had to swap the 3.5 back on and I noticed right away that going back to my stock TB and manifold, completely erased the jerking. Was smooth as could be.

I was able to overcome some of it with Flashpro, and that definitely reduced it, but the jerking is always there (if not as prominent), and still in low gear sometimes it just goes apeshit. So I think over time, it just ripped the pipe in half.

When I installed my 3.7 TB, though, I re-used my 3.5 MAP sensor (I lost the one that came with my 3.7 but oh well). So I just ordered the RDX MAP sensor for 40 bucks and will do the Anil-approved method of making it attach to the stock sensor plug, and see if that helps.

If the RDX MAP doesn't fix it, I will probably be reverting back to a 3.5 manifold/TB and just PnP it.

 

If you use the 3.7 senor, it should solve your problem. I have had mine installed for about a year now and its flawless. Since the 3.5 is a smaller diameter TB, it probably has to open more to get the desired amount of air through. Since you have the 3.5 sensor on the 3.7, its opening the TB further than it should, in turn causing the car to surge.

 

exactly my thoughts.

Glad you can lend a bit of confirmation to that - hopefully I will have similar results!

Richie cut me a great deal on a replacement for the rear PCD, because he is entirely awesome, so including the 3.7 MAP sensor, I'm looking at about 150 bucks to take care of this.

 

Are you running all OEM engine mounts?

 

nope I run XLR8 mounts, as well as the XLR8 ETD

 

Who would have thought you'd be working on PCDs again so soon after installing my HFPCs... I'd almost feel bad if I knew you didn't love this stuff.

 

15 minute swap to put a new rear pcd in! ezmode i just need parts

 

Wow. I might have to look into this 3.7L TB sensor as well to prevent this.

 

I have the same problem when I release the gas pedal, I think this is caused by the bored TB. Maybe too much vaccum now. The jerk is when we are between 0 and 1% throttle. I would love to have a fix for this from hondata but there's not a lot of tuning possible for this as of now.

 

Are you using a bored TB? I doubt the 3.5 map sensor is the cause of this? I would like to solve this problem too...

 

awesome carnage!!!!!!

mine always breaks at the weld.
I can change in about 1 hour including welding time. lol

 

glad someone else appreciates it. I laughed a lot when I saw it.

I had the problem even before I got the TB bored.

 

with the 3.7 TB stock bore? or with the oem 3.5 TB?

 

3.7 stock bore using the 3.5 map sensor

 

This is what Richie put together for me as a replacement, lol:

 

Nope, just an off the shelf ZDX TB and I have never had a single issue. I just used a dremel to trim the guidelines on the plug and made it fit.

 

mine ends up sounding like an airplane.

major exhaust leak right at the heads! lol
WHen I re-install I appreciate that I have torque again


*edit
Hmmm, wondering if that fix will permanently fix mine.

 

Sometimes on the stock TB going downhill with super light throttle, after my dual exhaust I could feel the same engine jerk sensation... I would think it's linked to vaccum level too high for the oem ecu MAP values?

 

agree that is possible as well. The map sensor is cheap enough that I'm willing to give it a shot - if that doesn't fix the problem, then I may look to find someone who will let me yank their stock 3.7 TB and see if the problem persists. If the MAP sensor doesn't work, then that's the only way to be sure.

 

I am welding those "bars" on mine right when I get them so I dont need to worry (as much) about this issue!

 

If you're getting that much movement, wouldn't a flex section be better?

 

if there wasn't a way to correct the movement, I'd say yes I agree with you and get a flex section. But the movement I've been experiencing is not normal for this car especially with XLR8 mounts and ETD installed. This is pretty harsh and the goal should be to eliminate the movement that caused the crack.

In this case the movement should be remedied either by the new MAP sensor, else a different TB - again given that going back to the 3.5 completely eliminates the movement, something having to do with the TB is causing it - either the bore or the fact I'm currently re-using the 3.5 map sensor.

Truth be told it's good this happened because now I'm actually focused on fixing the movement. Before this, it was a daily annoyance with driving the car but I just lived with it and found excuses to be too busy to do anything about it. As a result, my procrastination was cause for a busted part on the car. So now I'd rather just fix the movement altogether.

 

Odd. I have the 3.7 MAP sensor and bored ZDX TB and don't have any jerkiness. Just a high initial idle that eventually settles and more pronounced rev hang. Are you sure your mounts are all good?

 

yeah i inspected the mounts for donuting and they are fine.

you have the 3.7 map sensor. I do not. I have the 3.5

again that's what I'm leaning towards as the root of the problem.

Once my 3.7 MAP sensor arrives and I put it in, I will report back. If that doesn't fix the problem, then I will assume that there was a problem with the bore that KMS did to the TB and it will need to be replaced.

 

I have a bored TB from maxbore and I have the exact same problem as you. So it's not the ''boring of the TB'' that gives those problems...

 

I saw you're still on the 3.5 MAP sensor. Didn't mean to imply we had identical set ups. Just seems strange some first/second gear surging would wreak that kind of havoc. Granted, you're probably making 30-35 whp and 20 more ft lbs than I am, but I bet most FBO 6MT drivers get on it pretty good in first gear pretty often, so maybe this is just an isolated incident. Maybe it was a weak casting? Hopefully the 3.7 sensor will smooth things out for you. IIRC, I did run my stock MAP sensor for a week or two with the 3.7 mani/TB and didn't have any issues. I only swapped to the 3.7 sensor in the hope of smoothing out the idle/rev hang, but it didn't seem to help.

 

To fix your idle/hang issue, did you try to match your oem tb (tps) voltage value?

 

well seems interesting for the metal to be brittle like that and break to clean? I would have thought it would bend first?

 

Not really. It seems the heat from the weld made the metal brittle and break like that. It happens all the time on cheaper turbo manifolds. There is a ton of heat on that bend.

 

I know the 3.7 MAP sensor seemed to work, but I think it's just a placebo honestly. I looked up the part # for the 3.7 sensor and it's the same as the new Civic FYI.

LOL @ the carnage, and LOLLLLLL @ Richie's beefed up jail cage PCD. Love it. Richie is the man.

 

Not yet, but I remember reading about it. Maybe I'll do it when I do a 4" intake. Been putting that off too long.

Lol, jail cage PCD.

 

"jail cage PCD" is how I will now refer to my PCD's on a go-forward basis. Done and done.

 

What type of steel was used for the pcd's? Is it 304 stainless steel? This is just speculation, but maybe the temperature exceeded the limits of the 304 stainless enough to make it brittle and crack. I have read that you should only use 304 stainless for the cat-back because of these heat issues.

After looking on their website it is 304 SS. They even talk about this happening.

Quote from their site. "Over the years we’ve made several improvements to perfect this product. The biggest challenge was getting a round pipe to fit smoothly into an oblong hole. By stretching the pipe thin spots were formed that were prone to cracking. Combined with the rocking of the engine, cracking failures were fairly common. To solve this problem we tried using flex pipes, thicker materials and extra thick welds. These were all band aid fixes that never completely solved the problems. Until we decided to take a new approach."

I know people are gonna flame me for saying this because he makes parts for your car, but I just don't think rv6's quality/craftsmanship is that great.

 

The simple magnet test will show that they don't use 304ss on their Jpipe. Also mine was all rusted out on the outside after one winter. The rest of my custom dual is made of real US or Can 304ss and there is no rust at all after one winter. So I think the welding and craftsmanship is ok but they use cheap Chinese metal...

 

PCDs are exposed to extreme heat and stress. Especially on a car that has issues causing the engine to jerk violently. At crack simply formed at the weakest point and spread. There is nothing cheap about the materials we use. We only use high quality annealed USA made 14GA (0.083") 304 stainless tubing for our PCDs. It is thick and heavy and usually reserved for turbo manifolds and downpipes. Most exhaust components are 18GA (0.050") or 16GA (0.065").

Our current PCDs are suited for 99% of the customers out there. However we took this MAP sensor issue as a challenge to make something stronger. If you feel that your current PCDs are insufficient please contact me.



The cracking failures were common with the V1 and V2 PCDs, we used tubing to fabricate the bends that comes off the head. Now that we use castings the V3 PCDs are super reliable. We have 400+ sets of V3 PCDs out there and have only had around 6 failures. The failures were usually caused to blown engine mounts or not using the brace connecting the rear PCDs to oil pan.

You are also overlooking customer service. I stand behind my products and will do my best to make sure you are satisfied. If something fails I either replace it give you a excellent deal on replacements.

Your test is flawed. 304 stainless steel is non magnetic in its annealed form such as unbent tubing. However cold working processes such as mandrel bending causes it be be magnetic. Here we have a 304 stainless bend that we use. You can clearly see a magnet sticking to it

http://www.azom.com/article.aspx?ArticleID=1140



As for the rust. Stainless is corrosion resistant not corrosion proof. When exposed to high heat and the elements it forms a surface rust. However the internal structure is intact. You can easily polish stainless back to a shine however the rust layer will form again after time.

 

^ Why we <3 Richie.

 

Maybe I should have also prefaced a bit in my original post -

This will mark my 3rd PCD - I had an older set with the weaker welds on my '05 TL before I sold it. I noticed they were cracked at the weld when I went to swap them into my Type-S. I called Richie and he swapped them out for new V3's (the better welds) for like 200 bucks shipped. Awesome. Those worked great and I sold them later for HFPC's. Never had any problems. Went back to PCD's about 5 months ago and the result is what you see in my OP which is entirely due to abnormal bucking/jerking of the vehicle.

I've been using RV6 parts on my TL's for 5 years now and the only legit problem I ever had was the PCD welds which were redesigned and Richie took care of it reasonably for me.

Richie sent me the replacement pipe here that you see with the 3/8" steel braces welded on for $125 shipped, which is very generous considering the reason the pcd broke in the first place was because of my procrastination in fixing the jerking of the car.

 

Im starting to hear a small exhaust leak in mine as well. Ill have to check it out and make sure its not cracked. However, I wont be replacing mine because Ill have the turbo manifold sitting and ready to be put in.

 

Richie,
That was the politest bitch slap I have ever seen! Nice work! :-)

 

I was trying to figure out how to say just that... and you nailed it.