Redline

Sorry -- I know this has been discussed a lot.

I had a 4th gen with the Stillen y -- if you sat in neutral and revved the engine to around 4k and let off the throttle, as the engine returned to idle, there would be this loud metallic buzzing sound. Kinda sounded like a loose heat shield or something. Tried for months to fix and ultimately got rid of the car for my 5th gen.

Has the 5th gen ypipe eliminated this "feature"? I've been a little gun shy about modding the exhaust on my 5th gen because I got used to the quiet smooth power. Now I need a little more oomph and am thinking about the ypipe again.

Just wondering what to expect. Also, did I read here correctly that the 5th gen y only eliminates ONE cylinder bank precat? That seems goofy if it's true.

Max_Gator

Short of it is the y still makes that noise. I have a cattman and at high rpm it makes the noise. It is much quieter than the old y-pipes, however.

You are correct about only eliminating one pre-cat. The other stays. I believe the 4th gen was the same. Apparently, you can't get rid of the front pre-cats without causing the ECM to go wacko.

psing23

ok what i heard is that the stillen y-pipe has the "bees in a can" sound that is very annoying... the Cattman pipe does not have this.

If you have a Fed spec car then it eliminates the precats... if you have a cali/nled spec car then it only eliminates 1 and not the other one...

but some of us are trying to work on elimination both...

Desert Pearl

This is exactly correct. The front precat on CA emissions models is not removed by installing an aftermarket y-pipe because it is somewhat built into the front exhaust manifold. Remember also that all 2001 models are CA emissions... no more Federal models.

I have already purchased a '95-'00 Federal style front exhaust manifold and have also relocated my downstream O2 sensors to after the main cat. All has went well so far... no check engine lights. As soon as I can spring for a y-pipe, I'll finish the project. I am still looking for a '95-'00 front exhaust manifold heat shield though. I want it to look stock from above. Pics will be coming soon.

psing23

how does it look now? where is the front exhaust manifold located? i wanna see what it looks like in my car... even though i got a cali.. just to kno where it is

hawkdog

I just put mine on yesterday and I really like it so far. I do hear the noise you are talking about, but I actually like it....sounds kinda rough like a race car....mostly when the car is engine braking is when I hear it though. I have the Fed-Spec Model so I got rid of both pre-cats...and i've had absolutely no problems with the check engine lights or a low idle. So I guess I'm a happy y-pipe owner BTW, it pulls like a fricking freight train now!!!!

My 4DSC

well...
my car doesnt have a "bees in can" sound at all...
but i have a supercharged 5th gen w/ the 3" y-pipe...
so maybe its slightly different...who knows...
(my car didnt get any louder w/ the y-pipe & stock exh)...

just for the record...
the FEDERAL SPEC 5th gens (my car) use a 4th gen y-pipe...
and it replaces BOTH pre-cats...
the CALI SPEC 5th gens only eliminates one precat...
(but i think that was already mentioned)

MaineI30

I have a Cattman SS Pipe. My car got a little louder, but just barely. Mostly like a baby putt-putt sound (at first I thought it was a little leak, but the connections are TIGHT) .. but almost imperceptible.

/aac

y2kse

iTrader: (1)

Let me make sure I completely understand what you're saying. It appears that you've:

1) Removed the CA/NLEV-spec front exhaust manifold (including the front pre-cat) and replaced it with a Fed-spec front exhaust manifold, and

2) Moved the aft O2 sensor from the the front exhaust manifold to a position behind the main catalytic converter.

After doing this, your car did not generate a check engine light.

Is that correct?

UMD_MaxSE

iTrader: (1)

dude....post this in another thread by itself....this is pretty big.....and pics would be awesome

y2kse

iTrader: (1)

I agree. Desert Pearl, start a thread with a subject like "Exhaust manifold conversion" and post your info there. It will get lost in this thread.

PKO

Will the '95-00 Federal style front exhaust manifold bolt on in place of my CA version with the pre-cat? It would be nice since I already have a CA Cattman y-pipe. I was quoted $250 by a local muffler shop for a custom manifold to replace my pre-cat. It seems the upper flange on the pre-cat is unusually large. I'm hoping I won't have to spend that much. My custom b-pipe has the O2 sensor nuts in place and ready to go.

Desert Pearl

Okay guys, here's the deal. I have NOT installed the fed exhaust manifold yet, because I can't bolt my CA y-pipe up to it. I HAVE relocated the O2 sensors to after the main cat. This DID NOT generate any check engine lights. I have put many pics on my website showing where I am right now. I threw this part of my site together rather quickly (in response to this thread to be exact). To view these pics you can go to the site listed in my sig and click on Future Mods #5 and it'll take you there. You could also click on this link www.desertpearlmax.homestead.com/O2_Sensor.html
to go there directly, but you'll miss out on all of my fancy pics and sounds. And finally, don't worry, as soon as I have solid data, I'll post a new thread!

Desert Pearl

You are correct, the '95-'00 Federal front exh manifold will not bolt up to your stock CA y-pipe. It will be substantially easier to make a custom pipe to bolt up to the Fed exh manifold though, because of the flange issue you mentioned. In fact, you might be able to find someone on this board that bought a Stillen 2-piece y-pipe for their CA emissions car that might be willing to sell you the second piece for cheap. You can pick up a used fed manifold pretty cheap too. I paid $50 delivered... not bad considering how much that stinkin' thing weighs. You can go to www.Car-Part.com and search for one. If you want more detailed info, plese checkout the site in my last post.

PKO

The info on your site was great! I think I'll take your advice and try to find a fed exhaust manifold. Thanks.