I just had my pacesetter long tube race headers installed last week and all is perfect except for one thing. When I accelerate from a stop, there is something hitting the driver's side header. The harder I accelerate the more prominent it is. It's not a "cling" or "clank" but rather a "conk" if you will... When accelerating hard, between 5,000-6,000 rpms, something is hitting the header somewhere around 3-4 times per second. I can also feel it hitting with my feet. What is it and how can I fix it?

 

Header/Y-pipe could be hitting heat sheilding, G-load brace, floor boards, FUEL LINES , Transmission parts...just get under there when the exhaust it cool and shove the pipes around a bit. It took me awhile to find my rattle.

-Dustin-

 

Not trying to be funny but find where it is hitting and either clearence the headers or what it is hitting. I recently worked on a car that had an exhaust pipe hitting near the engine and would not rev over about 4000 without cutting out like crazy. I am sure it was because of knock retard. Trip to the old muffler shop fixed the problem and now it runs like a champ again. I would get under the car or get it on a lift and see if it may be a simple fix of doing it yourself. with the proverbial BFH or need to take to to an exhaust shop. I hear all the time about people having to bend thier floors in or clearence thier crossmembers

just my 2 pennies

 

my exhaust bone stock did that right at the I pipe to y pipe connection, it was hitting that brace when taking off from a stop, so it can be a number of things down there

off topic, but how does your car feel with the mods you have and 2.73's? does it seem like they are sluggish or holding you back at all?

 

Does the "conk" happen just once or is it a continuous thing? Once would sugest chassis flex is to blame.

 

2.73's hold stock LT1's back, hell the V6's came with 3.08's. Change your gears to 3.23/3.42/3.73 and youll be much happier. Back to topic.

-Dustin-

 

Well, it doesn't feel like it's pulling as hard as higher gears, obviously. My friend had 3.23s in his and there is a world of difference between mine and his old gears (now he's got 4.10s). But then again, I punch it and the wheels spin all the way through first, to around 45mph and then I get a second gear scratch. Holding back? Yeah probably a little. I do a lot of highway driving, so I'm still debating on whether or not to get some gears.

Anyways, about the headers hitting. The "conk" happens if I gas it somewhat hard from a stop, and then if I continue to accelerate hard it hits 3-4 times per second at higher rpms. I'll probably take it to a lift this weekend. When I got my exhaust hooked up, the guy said it was touching in a lot of places -- don't think there was anything he could do.

Edit: Also, with it hitting like that, will that degrade performance, such as the computer picking up knock? Sorry if that's a stupid question.

 

When my car warms up my passenger side mades noise too - but only under loaded idle...idle in neutral/park is fine and anywhere baove 1k RPMs under load is stops ...pisses me off. Only thing i can see that would be hitting is the heat shield above the CAT...but there is no way for me ot really FIX it so i just let it be lol.

 

is there a general area the noise is coming from? closer to the engine, closer to the I pipe? i mean if the guy said it was touching in a lot of places, then under load i would expect it to hit wherever its touching, but i would think you could feel it too though, so its hard to say.

 

Heat sheilds are even up near the firewall, I removed all mine to save some rattling. As far as the headers touching alot of places, thats not a good thing and needs fixed ASAP. If its too close to fuel lines or touching a floor board your car is going to be up in smoke someday.

-Dustin-

 

I can feel it. It feels like it's right under the floorboard, but I don't know. I'll have a look on Saturday I guess.

 

get some new motor mounts