Borla Header Lawn Mower
 

Good day everyone,

I recently installed a new Borla UEL header and am experiencing a bit of a weird issue. When I start the car, it sounds like a lawn mower. As soon as I put the car in gear and drive away, the noise is much quieter and slowly goes away as the car heats up.

I should mention that I reused the gaskets when installing the headers and the only exhaust modification I have, are headers.

Thanks,
Gilbert

I would suspect it to be the gaskets. Most gaskets are meant to be used once as they crush/deform during installation. Based on what you're describing, it sounds like you have a leak at the gaskets and once the car is warmed up, the gasket/pipes expand and fill in the gaps. I would install new gaskets.

I have my money on exhaust leak at the gaskets where they meet the head.

Scott

What's weird as I drive 3 feet, stop and the noise is gone. If I sitting still and rev the engine, the noise remains at idle.

Sorry you didn't get to see my post before you installed yours: http://www.ft86club.com/forums/showp...&postcount=296

I think that you have a leak from re-using gaskets and the flanges on the header may be warped like many others. A bunch of us are getting them replaced under warranty with Borla right now due to warped flanges that cause leaks... :(

Odd. Could be due to heat expansion is more exaggerated with headers.

First thing I would do is eliminate the easy. Check around your gaskets for black scoring which would indicate a leak. It would be best if you could get under the car with the engine idling. (SAFELY!)

Once you have ruled out exhaust leaks, then move on to more possibilities such as your exhaust sensors.

Scott

Forgot about this! :happy0180:

Scott

I am waiting on a replacement header from borla as well.
Cold start sounds like a tractor, once warmed up it is not as bad due to the metal expanding and sealing slightly better.

Our car does the same thing. The high idle when starting the car produces some extra noise, and once the car idles down it is fine. There is no leak. We have tested this with the car in the air searching for leaks on start up.

Most likely the thin walls of the header passing the noise along. The stock system has thicker walls plus shielding to keep things quiet. The cat also helps with noise.

^what speed factory said. Took my car back to @Pure Automotive just to make sure there was no leak and everything checked out fine. Even with stock exhaust car was louder when cold start until it drops down below 1k. I just don't move it until it's warmed up. catless=more stinky anyway! FTW

Awesome avatar lol

When I pulled mine off I had carbon/blowby on one of the gaskets, the tractor sound was most definately a leak in my case and the flange was most decidedly warped.

I know the header is a little louder on cold start due to the thin walls, but many of us have actual warped flanges that do not seal properly as the tick/leak sound was also there when warmed up, just not as loud. It sounds like someone is shaking a tin can full of thumbtacks

Damn, I thought someone managed to put a Borla UEL on a lawn mower.

That would have been BA.