Do I have a leak? (with video)
 

Hi guys I recently installed 2nd hand UEL headers and overpipe in preparation for running e85. Rest of the exhaust is stock. Being 2nd hand they did not come with any gaskets.

I re used the stock gaskets as I didn't have chance to get new ones and I figure it's only a 30 min job to replace them if I need to. The stock ones from header to OP and OP to front pipe were thin metal ones and I'm not convinced they would seal well?

Anyway it seems louder than I expected it to be (on cold starts) even similar to when I ran a muffler delete.

When I accelerate on low throttle it sounds like a hiss/whistle to me but I'm not sure if that is just because of using an uncatted header with no shielding etc. I also have not put the metal undertray back on yet.

Here is the video below including a few revs and I covered the tips with rags on and off a couple of times to see if I could hear any differences. Let me know what you guys think. I appreciate it :)

[ame="https://www.youtube.com/watch?v=9p5M7kcZzPc"]20150630 142117 - YouTube[/ame]

I'd rethink that time estimate. It took me a few hours to do that last weekend. Granted, it was my first time doing it alone, I was on jackstands, and I didn't have all the necessary tools handy.

I'm on a crappy work laptop so I can't hear the video too well, but it sounds like a leak. You could always pressure test it to be sure. I shoved a towel up one tailpipe and then ran a shop vac exhaust into the other. I then sprayed soapy water on all the flanges to see where bubbles were forming. Also, if you start using E85, sometimes you can see water dripping from any leaky connections.

Even when you fix the leaks, the cold start is going to sound crazy loud, almost like a pulsejet. It's just one of the downsides of having a catless header. It's possible to alter your tune so that the cold start process isn't nearly as loud, though.

I can't hear anything ........ except your car's engine running.


humfrz

samething here.

when car cools down that header is cold enough to touch it by your hand, put it up on jack stands and start your car. crawl down little and put your hands near joints between header and op to see if any air is leaking. you definately can feel it. if not, move to OP and FP section.
I would replace new gasket by the way

When I had installed my entire exhaust system (headers back) I didn't think I had leaks.

I was totally wrong.

FP to Catback interface had a leak on the donut gasket and both flanges on the axleback were leaking in some way.

To find them all I had let the car cool down considerably, jacked it up, and started it for like 10 seconds while I dove under the car checking all the flanges. Turned it off quickly so heat doesn't build up and seal some of the flanges.

That process made it really easy to find all the spots without burning my hands. I just curled my hand around both sides of the flanges, without touching the interface, to feel for leaks. Leaks are extremely obvious.

If you're uncomfortable sticking your hand around the pipes, use a sheet of paper or something very flimsy.

I just installed my header and have a crickery, crick crick crick sound at low rpm. I also thought it was a leak but I did a tune afterwards and they did not notice anything. Recently somebody mentioned that they had the same sound but it was expected since the header's piping is thinner than oems and not having the shields, the sound is louder.
Do what Rybot suggested just to be sure.

I think the best way to find leaks is this.

Turn off car.
Safely jack car.
Put on jack stands.
Duct tape a shop vac to the tail pipe.
Blow air into the tail pipe.
Grab a bottle of soapy water spray at suspected areas.

Ok thanks guys I put it back up on stands and tried to feel for leaks before it got too hot, only took a few seconds before it got too hot. I didn't notice anything that stood out to me as a leak.
I am going to try the shop vac method once it cools down.

If you didn't feel any air blowing on your hand at any of the flanges, be it the top or bottom of the flange, then your exhaust system isn't leaking. Idling it should provide plenty of pressure to feel for leaks using the method I described since it happened to me.

Fucking genius. Never thought to use it for exhaust leaks. This one goes into my big bag of ninja mechanic's tricks.

I used a potato back when had my rx7.Just put at the tailpipe while the car was at idle, then quickly go underneath and tryed to hear the air whistling.