Rep Power: 0

I recently purchased a Megan Racing Header and began installing it on my 99 Ex. Simple swap, right? Of course, problems will always occur. I managed to remove the stock exhaust manifold properly without stripping the bolts and although I couldn't remove the last bolt holding the manifold to the down pipe, I was still able to successfully drop the entire manifold and header together. Apparently, removing the bolt/springs from the down pipe to the cat can be extremely problematic in this swap, but I lucked out and the cat came right off of the down pipe. I was able to remove the O2 sensor after some work and when I got to installing the Megan Header, a couple problems came up.

First, as a check, I want to know if anyone can confirm that the ft. lbs. of torque on the head bolts is ~25 and ~50 for the manifold-down pipe bolts.

As far as problems go, I had the O2 sensor in my new down pipe (the Megan header and down pipe are attached), but when I placed the header to the head and went under to look at my O2 sensor, it is right up against the wheel axle. (My original down pipe had the O2 sensor to an angle out away from the axle while the Megan down pipe has it vertical) Upon tightening everything down, could the O2 sensor be far enough away from the axle? If so, I think that I have to remove the header and down pipe again, remove the O2 sensor, then place it in as the final step.

The main problem I have though deals with attaching the down pipe to the cat. As I said before, I got lucky removing the two pieces...the bolts came right off however rusted and the springs came out fine. Problem is...I can't figure out a good way for reattaching the two...the spring takes quite a bit of strength to depress and I can't get the two pipes close enough together AND depress the springs and attach the bolts with only my two hands.

-One solution to this could be to have another pair of hands helping me out. I also thought that clamping the cat to the down pipe, then attaching the springs would work, but the system isn't steady enough. Is there any easy one-man or two-man solution to this? I think that the O2 sensor problem should disappear once I have the header bolted properly to the head and the cat bolted properly to the down pipe.

 
Rep Power: 388

Loosen up the bolts on the other side of the cat to give you a little more slack..

Also ditch the spring loaded bolts for some better bolts with washers. The stock spring loaded ones get pretty frail from all the heating up and cooling down and are more complicated and expensive then they need to be.

I think your torque ratings on your spring bolts are wayyyy too high. The exhaust system bolts arent very high in torque because they expand when they heat up and shrink when they cool down. You only need it tight enough to create a seal, anything past that is just icing on the cake and too tight is asking for problems when you go to remove all that and go back to stock.

 
Rep Power: 0

Oh, definitely too much for the spring bolts, I meant the torque on the bolts holding the header to the down pipe. Loosening the bolts did help and replacing the springs certainly would have helped. Basically, I had to clamp down the springs and tie wire around them to hold them down; this allowed enough time to attached the bolts again and and bolt the cat to the down pipe. After that I simply clipped the wires. The system is completely bolted down now.

Lastly, it turns out, after everything was done, the O2 sensor does not have enough room to be placed in front of the cat near the back of the down pipe. The Megan Racing header provided another place for the O2 sensor near the middle of the header (This was made for dx, lx, etc. models which need two O2 sensors). This is great because it means I can move my O2 sensor there. I just need to extend the wiring from the old O2 spot to the new one.

Starting the engine without the O2 and running it for a bit, the new system sounds fine, no leaks or problems, but the check engine did come on (as expected) with expected symptoms because of the missing sensor; so no review of Megan Racing's header yet.

Hopefully the wiring will go down without problems...though after this swap, I doubt it

Anyway...after all this work, hopefully the car will run and sound great.

 
Rep Power: 0

Let us know how that works for you when you get it ironed out. I was looking into Megan,

 
Rep Power: 246

The proper spring bolt torque according to the Helms FSM is 22 N-m or 16 lb-ft. The header nuts for the exhaust manual is 31 N-m or 23 lb-ft.