did you get achance to put those gm gasketsback on their? i know its a pain but try it out........

 

i have nothing productive to add, but you avatar is amazing! lol

hope you get the issue figured out. ;-)

 

Not yet. Doing it this afternoon. I went and picked them up yesterday. Shouldn't be too hard now.


She is a pretty amazing woman too. She hates my "Christine" though.

 

Changed the header gaskets back to MLS gaskets. Still have the same problem. The banging of the y pipe is now even worse. Sounds like minors tunneling under there in first and second gear and at idle it rattles really loud. Got some of my stock LS1 stuff I'm selling. Gonna take that money and do duals. That should get rid of the rasp and knock sensor issues I hope.

 

Remove that stamped metal crossmember piece. Its in your second photo. It doesn't do anything but get in the way.

 

GM MLS gaskets are best for this, so there is no need to go with another brand etc. After you have it sealed up spray some soapy water where the header flange meets the heads, bubbles will let you know if it is not sealed up all the way.

Your y pipe doesn't look that bad, you can pull it all together and run open headers to see if it is your y pipe causing the problems. Y pipes are weird because if they are not built right the merge will cause all kinds of problems. Hesitations, Misfires, Backfires, Rasp etc. It has to deal with the pulses and exhaust scavenging. A improperly built y does way more harm than good. This is the best y pipe setup I have ever seen on our cars https://ls1tech.com/forums/generatio...m-y-pipes.html first page you cant miss it!

 

tune after installing headers? your kidding me, headers allow the motor to breath a little better. so that in it self is helping and the computer doesnt have a sensor saying "o god its gettin rid of more air lets through more in!" yes a tune will not hurt but it is not the cause of your problems. a stock tune should run fine with headers. i no this post is late but after reading this i had to say something lol let us no when you get her sounding good, ( or the way you want her to sound!)

 

Took it off. Also added some heater hose to the pipe at a crossmember to lower the exhaust a little more. Maybe that'll keep it off the torque arm a little better too. It did stop the rattling at idle. I'm about to go drive it.

 

I don't think I said anything about the tune other than I got one. Maybe someone else suggested it. The stock tune ran really rich and my SES light was on from the AIR delete and rear o2 delete.

 

My buddys ran pretty bad after header swap, but found out that one of his 02 extensions turned out to be bad have you checked them ? Did not read all three pages sry if this has been discussed already.
Edit.. have you checked your o2 sensors made sure there pluged in good and no burnt wires i went through the thread and did not see anywhere talked about this.

 

Yeah checked that first. The thought came to me because I made the extensions myself. They both checked out fine. I've been messing with the exhaust and it's getting better. I'm sure it's knock sensors from the pipes banging. It was real bad when you got on it in 1st or 2nd. If you waited until 3rd gear it was fine. Removing a bunch of useless junk under the car a little pipe bending at home, reshaping the heat shrouds and some heater hose between some close quarters areas has it better until I can get the duals.

 

buy a minivan