[teal89]

Long story short, normal driving and every now and then a punch of the throttle it's ok. WHen I stay on it for a while, I hear this very noticable chatter coming from eithier the front of the car or just right in front of the firewall. What do you think of that?

89 5 speed

Also, why in the hell do I have two sets of cats on my car?

 

[ryans88gt]

Either something loose rattling like the smog pump hoses, or your clutch disk and pressure plate chattering.

 

[teal89]

I don't beleive you can hear hoses chattering, more like a tiny knock noise but I am going to lean towards the clutch disk and plate chattering. So What, I should move the tranny housing nd re-tighten the half ass tighten bolts or remove the disk and plate, and re-install it?

Also it only happens after 4000rpm. ANything less is ok and for a head start, there's no knocking noise in the engine and no noise when you listen to both banks so lifters and everything are good

 

[crowbar73]

Do you smell a burning smell like the clutch may be slipping??

 

[trueblue01]

4 cats or as the scrap guys refer to them pre-cats. Space limitations more than anything. They get damn hot and in order to maintain enough clearance Ford used 4 smaller ones instead of 2 large ones.

 

[HACKGT350]

the first set of cats are 2 way cats they eliminate hydrocarbon and carbon monoxide. the second set of cats are 3 way cats they eliminate hydrocarbon, carbon monoxide, and NOx. as for the rattle get under the car and start playing with stuff thats very very hard to diagnose with out being able to sit in the car and hear it ourselves

 

[ryans88gt]

I don't beleive you can hear hoses chattering,

The smog pump hoses and egr hoses are metal behind the engine and have a tendency to rust through and rattle against things...so you would be able to hear them.

 

[JBIGBOOTSY]

DETONATION. Does it sound like a bag of marbles?

 

[HACKGT350]

DETONATION. Does it sound like a bag of marbles?

you know i never thought of that. that could be it for sure. do you have your timing advanced and what octane are you running

 

[teal89]

Damn I never thought of that myself, hell yeah it sounds like that. Maybe more of a **** load of plastic parts falling onto gravel in a wide open area that's real quite LOL

HackedGT350, yes I do have my timing advanced a little and running "water" 87oct. If I retard the timing, my throttle response will be all slow and **** please tell me to either buck up and use better grade of water or to retard and make power somewhere else LOL...

Also since all other cars are made with two cats, can I at least remove one or the other, I am getting jacked, beat up and shot in the face on horsepower with 4 ****ing cats on my car LOL. My car actually fells like it's fighting against those cats other than this issue I have now. I am about to get offline now But for those wondering, I will retard the timing back some and drive it a keep going to see if the noise goes away.

 

[Trick Tuners]

Here is some info on detonation. Never let it detonate!!!!
Detonation Explained

 

[HACKGT350]

my timing is at 14* and i have to use 93 octane i would bump up your level buddy you dont want to destroy that motor

 

[HACKGT350]

as for the cats dont cut them out just get a new 2.5in h or x pipe with a set of high flow cats in it or get and off road and when you need to pass inspection if you need to throw the old h-pipe back in for the inspection

 

[JBIGBOOTSY]

as for the cats dont cut them out just get a new 2.5in h or x pipe with a set of high flow cats in it or get and off road and when you need to pass inspection if you need to throw the old h-pipe back in for the inspection

+1, don't gut cats. A gutted cat flows for **** too.

 

[teal89]

FIXED! Yep it was timing. I took it back some and drove it. Actually gained a lil power from that as well as I can see my powerband from the rpms race after 2200rpm. I test drove it today and no noise at all. Just the noise of the engine coming from my flows and 4 cats.

NoNo guys, i don't plan to remove all four cats. Although I live in a non-emissions area, I would love to keep the lower set of cats. Hell I might cut them all off and replace with some high flow cats. The places I've been requires only one cat per bank. If it's a true dual, then they need to see one cat per side. If it's manifolds where it goes from dual to single, they need to see one. But as I can feel my car bitching about lack of power befcause it's getting held back by those cats. I'd like to remove just one set, so which ones can I remove?

 

[fogged306]

You probably would be fine with the timing advanced if you used 93 octane.

 

[HACKGT350]

dont gut the cats at all. like a said get a nice aftermarket h or x pipe with high flow cats in it. it has one on each side. as for the timing advance it to like 13* and put 93 in it then you will feel a real power gain

 

[teal89]

Well I had it around 14*-16* degrees advanced and had a sample of big power gain under 4000. After that it was smoke and a "bag of marbles". I will probably stick with the 87 until the gas drops a tad and use the silver can octane booster which will put me at 97-99oct. but I will do it right the first time and use the 93 water instead of 87 water.

For the H and X pipe, I already have a custom placed straight pipe in the posistion in place so I won't buy an h or x pipe with cats already placed. I will cut the one's I have and replace with two high flows. Not to say, I won't do it, but I'm trying to keep my custom work for a while. I didn't just buy a pipe and had them weld it in. I measured for torque base and pressure at the muffler shop and had it put in. Next on my list is getting some BBK headers so the car will have full breathing. That's where it's also starving. But no fluid leakin out my cats and defenitly no smoke at no rpm range after test driving the **** out of it today.

 

[HACKGT350]

if you use 93 with 13-14* you will get better gas mileage than stock timing with 87 octane as well as more top end as long as you use 93 octane. using 87 was taking away soooooooo much power on your top end. whats the diameter of your exhaust? straight pipes are no cats and no mufflers. if you had 2.5in pipes welded to your stock 2.25 pipes its not doing any good because its just as restricting as having the stock pipes

 

[Hunt_chevs]

+1, don't gut cats. A gutted cat flows for **** too.

yea, bends/flow on stock midpipes are weaksauce. an after market x or h will be a mad improvement