I have an interesting problem with a set of Maximizer long tube headers someone may have an opinion on. Yes, I know they are "Chine junk" but can we please get passed that please and leave this as a problem any header can experience.

Headers were professionally installed with existing OEM header manifold gaskets. The car starts up and runs great, no extra noises coming from the engine bay or under car. The car can be driven for roughly a .25-.5 miles with no issues then a sound starts coming like an exhaust leak. It's the tale tale leaky exhaust sound, not just some normal header ticking but rather a very obvious whoosh, tick sound from he passenger side compartment area. I've had my mechanic place the car on a lift but of course when the exhaust cools off the sound goes away so it's very hard to diagnose as they simply say "All headers sound like this". I trust these guys but I am 100% convinced they are simply not hearing the sound I experience when the card gets placed under load long enough to heat something up on the exhaust. I've owned enough headers to be convinced this is not a normal sound. I've recorded the sounds as well.

I've had them weld the hpipe / resonator pipe and replaced the rear muffler clamps with stainless good clamps to make sure everything is sealed. When on a lift there are no felt leaks anywhere.

My question, can this be header expansion? The reason I ask is the passenger side header is about 1 millimeter from the heat shield on the firewall. Is it possible the header expands and presses against the wall enough to make the OEM metal header gaskets leak?

 

the most obvious cause would be reusing the gaskets, he should have used new ones.

when it has the problem pop the hood and have somebody rev it while you investigate for leaks.

 

I've definitely tried that but the problem doesn't seem to happen unless the car is under a load for a small amount of time.

I can definitely order ACD OEM gaskets as insurance if you think it could still be those although I'm 99% convinced it's the collector donut gaskets not sealing under load when hot after this week of driving. I have a hunch it's the springs losing holding power when they get hot which causes the leak. It's been raining a ton here lately and I noticed when driving on wet roads the thing will seal up after riding through a puddle. I'm assuming water hits the collectors which cools down the bolts enough to hold tightly again. I don't see how manifold gaskets could be affected by this but I'm completely open to all possibilities.

The noise is dampened when braking heavily as well. For instance, while traveling 50mph, leaving the car in 3rd or 4th so the rpms are up, then brake hard without pressing the clutch, the sound dampens but doesn't go away completely. I'm guessing the collector just isn't sitting completely flush with the gasket although you'd never know it from being under the car (looks flush). Maybe the motor tilts forward which puts more pressure against the collector? This would explain the major leak under hard loads.

What are your thoughts on replacing the crap 4 spring/bolt combo they use on these with non-spring high grade bolts. Does this need to flex at all? I'm assuming they used springs for a reason but who the hell knows.

Thanks for the reply.

 

I'd say the header can move, and with the engine, not just heat expansion. If it really is 1mm away from something that's certainly one place to look. In the old days, they took big nails and hammered them in betw. each header and other places. Not sure you can do that here/this case. You may have to carve away some parts of the body/metal work. I've also read that new gaskets are recommended, not reused older ones. Several have used the old ones, then gone back and replaced with new and problems go away---that may not be your problem, but it could be down the road. Tell us what fix works for you.

 

New OEM gaskets are on the way! I'll report back what I find when I throw em on in a couple of days. I'm leaning more towards the header gasket on the passenger side now as well. Hopefully pulling off that old gasket will reveal some carbon trails.

Would there be any reason to not double up the gaskets on that side of the motor? (Old gasket against the head, new gasket against the header)

 

Long ago, there were some who used double gaskets, but I have not heard of anyone using it recently. Maybe as a confirmation, just call any speed shop and ask if they do it now. I tend to doubt it unless there are machined irregularities that can't be corrected--even then I doubt it would work or be used as a method.

 

If you chuck the mounting hardware in the trash that came with the kit and used quality bolts for the X pipe to header collectors bolting, weld the X pipe parts all together instead of using all the band clamps, and use the OEM X pipe to muffler pipe clamps, you don't have this problem.

So headers get installed with either the OEM gaskets on the car already if they are still in good condition, or you pick up a new set of OEM. The gaskets that came with the header kit, in the trash.

Down on the X pipe header collectors, use Grade 8 bolts and nuts (the bolts that came with the headers for the collector, trash them as well), and you will not have a problem with the header collectors connections coming loose.

Once the cats, and X pipe section have been fitted to work with the mufflers, then all that gets welded together instead of any band clamps.

On the rear X pipe to the muffler pipes, use the OEM band clamps, and again, the band clamps that came with the kit get trashed as well.

Lastly, on the plugs for the rear cats since you are not going to use the rear O2;s, make sure that the O2 ports are sealed correctly with thread plugs and high temp dope.

Bluntly, sounds like you are using the header gaskets, collector bolts and nuts, and bank clamps that came with the kit, and the root of your problem.

The header are good, the X pipe sections are good, but the problem is the hardware that comes with the kit is trash instead. Plus you don't want all the band clamp on the X pipe section (just the two OEM clamps that connect it to the muffler pipes only). Hence to drop the X pipe all welded together after fitting, just unbolt the front of it from the header collectors, remove the back band clamps that is holding it to the muffler pipes, and you have a solid all welded X pipe section alone.

 

Thanks for the suggestions. I already had the Xpipe welded and replaced the rear clamps with stainless. The only things left are replacing the junk collector spring/bolts with grade 8 bolts and replacing the used gaskets with new OEM. I'll be doing the replacement tonight one at a time to determine where the leak came from. It still drives me crazy when people say "That's just what headers sound like on these cars." I'm convinced most people just drive around with leaks then. When the exhaust is cold, you can't even tell this car has headers until the NPP is opened up and you get on the gas. But it's not header noise, it's exhaust noise from the rear. As soon as this heat leak is fixed I'll be a very happy camper with the install.

 

New OEM manifold gaskets are installed. The old ones were separated and the channels were pretty flat compared to the new ones so it was definitely a good idea to replace em. Although, the problem is still there. I'm convinced it's the donut gaskets, so now the grade 8 bolts are going in tomorrow. Considering I can feel a metal on metal vibration when the sound begins it tells me the header must be contacting the x-pipe. Maybe these gaskets flatten when hot. I suppose crushing them with good bolts may do the trick. ;-)

 

The issue was expansion like I initially thought. When the headers heat up they press against the frame of the car. When accelerating hard they move back slightly which causes even more rub. The exhaust shield was acting like a speaker and amplifying all of the sounds the headers make. The solution, a stainless hose clamp holding the collectors together to prevent expansion when they get really hot. Not ideal, but it works.

The issue wouldn't happen at any shop since it requires getting the car under load and getting them hot. Oh well, now I'm a happy camper with the things. Would I buy them again? Definitely not unless someone told me about this type of issue prior to the $500 purchase.

My biggest complaint with these is if you have a lowered car. Surprisingly I haven't hit anything but they do hang about 2.5-3" below the lowest point on the car which I really don't like. Try to find a header design where the collectors are up higher so the X-pipe can be tucked up higher under the car. Other than that the performance is great and my NPP makes it all just about perfect. Still quiet when closed and a hellish beast when opened up.

No tune yet but there's a noticeable difference SOTP *** dyno. After dealing with the noise for so long and then hearing how quiet it is now, I don't think I'll be adding a FAST 102 since I've heard all those noises come right back since it's plastic. Haven't said that. Is porting the LS2 worth it in this setup or would you just do a LS3 head swap?