A few days ago I started another thread complaining about loss of power and hesitation from the motor. I heard a whistling sound comming from underneath and I thought perhaps my cats were clogged. I decided to swap them out with the strait exhaust from my florida car. This is that story...

Saturday Morning 9am...

I drive home from work and the car is acting very sluggish, I can barely manage to coax it up the hills. I'm freaking out imagining the worst, blown apex seal etc. I get it into the driveway and prepare to remove the exhaust.

Saturday Morning 10am....

It took me an hour to remove the exhaust by myself. It is harder then it seems to get all those stupid rubber hangers off. One of the exhaust studs in the downpipe shears off as I'm trying to remove the nut! I also notice the old exhaust gasket on the downpipe is ruined and caused a serious leak... (which probably accounts for the whistling sound) And this might have been caused by backpressure from the cats getting clogged but I cant be sure. I decide, for curiosities sake to start the car without an downpipe or exhaust... it sounds like a chopper on steroids. I am too chicken to rev it up to check for hesitation as it would probably destroy my ears. I have an idea... to weld on another bolt to the remains of the broken stud and try and twist it out that way... No luck the weld dosen't hold.

Saturday Morning 11am....

I return from Auto Zone with some tools to drill out the broken stud. Some titanium coated drill bits and an easy-out drill bit kit. The helpful parts counter guy swore by the titanium coated drill bits. He didn't seem to think that a hardened exhaust stud would be any problem since he drilled out some broken motor mounts on a chevy with em. I'm skeptical so I get the easy-outs as well. I also get replacement studs, stainless nuts, lock washers and a new gasket for the downpipe.

Saturday afternoon 1pm....

I manage to drill through the stud but broke every one of the drill bits in the process. The drill bits were highly overrated as I had to sharpen them myself with a grinder several times. The special coating came right off as well. I then attach an easy out bit and hope to rip that stud right outta there. Snap! the easy out snaps with hardly any effort. What a peice of trash! To make matters worse the broken peice is jammed deep into the stud and is harder then the bolt which means I have no hope of drilling it out.

Saturday afternoon 1:30pm....

I return from the hardware store with more bits. I buy several expecting to have a bitch of a time drilling out more of the stud so I can loosen the easy out enough to twist it back out.

Saturdady afternoon 2pm....

Yay I manage to get the easy out bit back out. But the stud is so badly mangeled using a bigger size easy out to remove it wouldn't do any good. It would just jam up and and probably break like the last one. I decide the only option is to drill out the stud completely. For this chore I choose a super hardened concrete drill bit and attack it with a vengeance.

Saturday afternoon 3pm...

Victory! I finally manage to drill out the stud enough that I can peel out the remains off of the original threads in the exhaust manifold. I replace both studs with the new ones and install the catless exhaust that is also without its mufflers. (swapped these with my own mufflers a while back because they were in better shape) I start the car with nothing but strait pipes and take it for a test drive. If my theory about the cats is correct the engine will not have any hesitation issues.

Saturday afternoon 3:20 pm...

I return from the test drive with an ear-to-ear grin. There's nothing like the sound of strait pipes. I let it rip on a straightaway through the first 3 gears and am simply amazed at the difference compared to the old exhaust. There is no doubt I have solved the problem as there is not a hint of hesitation. I can actually feel torque all through the powerband. A corvette driver stopped at a stop sign off a side street gawks at me as I roar pass. He dosen't give chace... probably too intimidated lol

Saturday evening 6pm....

I have finished welding on the mufflers and installing the exhaust. I notice the downpipe off my florida car isn't stock, must have been custom... it's thick pipe with half the length and angle of the stocker... I believe this is the straightest exhaust configuration possible on an FC without a header.

In conclusion I must say that anyone in california who lives in an area that can get away without cats and straight pipes should do it! You wont believe the difference! (run mufflers of course unless your on the track)

BTW I have attached a pic of all the mangled bolts

 

Good job! I like stories that have a happy ending.
-John

 

yah i thouught i had that hesitation problem too went throguth the entire prosses off takign the cat out and replaced it with a bendable pipe, i replaced the eair filter which was horrably dirty, and replaced the fuel filter , and new spark plugs, the basics for a tune up rigth , well turns out it still ahs the hesitation problem and it just takes longer for it to happen, instead of 10 minuts untill i had 0 powere i had 15 minuts of roaring catless behavior, yup still does it, took the top front plug out and looked at it had gas on it, and took the others out none had gas on them, ive had this probblem for a while and put up several posts, but i dont think its the compression because it starts and runs fine and i can drive it it has power has hesitation at around 3 grand but i dont mind that but then it has nothign but when i drove it with the cat removed it had power after 3 grand it was like a turbo it kinda kiked in , almost like somehting with ignition was broke but wouldnt that be the same every time i started it if it was ignition. if anyone has any comments or suggestions, pm me ( btw the car is a 87 na, with a engine swap from a 156,000 mile engine to a 120,000 mile engine . )