I got an exhaust leak on the driver side exhaust manifold gasket and it shows ( By the engine sound and the backfires when revving the engine) Everybody thinks the car's pingin when they hear the car runnin ... But do you guys know how much horsepower i'm loosing ?

 

On a stock engine, probably none, may even be gaining a few, but it is not worth the hassle from local law enforcement or EPA peoples. The car will perform its best, and by that I mean get the best gas mileage and be drive friendly, with everything working properly.

Now if you have a high performance engine with enough compression a little leak wont hurt.

 

Nice ! Thanks ... I'll keep her that way then .

 

Same thing happened to me. Just get a 9/16 wrench and have at it. They'll tighten back up.


Also, if your inspections are anything like NJ's inspection, youll fail for it.
Another note: My exhaust system was pretty shoddy...there were a few breaks in it, so gas was getting out early in some areas and I guess it was impeding the flow a bit, because when I got it all welded up, my throttle response went through the roof. It wasn't a placebo thing either because I wasn't even expecting power out of it...haden't even crossed my mind, but I stepped on the gas, and it just took off way stronger than before.

Just thought I'd throw in my two cents.

 

Let me restate what I said, cause I didnt FULLY read what your wrote

If it is RIGHT off the manifold (like between the flange and cylinder head) then you WILL have problems. You will burn your gasket and the loss of backpressure right there will cause you to burn your exhaust valves. Best thing to do is see if tightening the bolts will cause it to stop, if not then you will need to replace the gasket.

The pinging noise everyone else is hearing may because by the ECM running the car rich and then lean because the O2 sensor is getting a false reading because there is oxygen escaping and coming into the exhaust flow from the hole. So in the end you maybe losing HP and damaging your engine.

Sorry when I read that I though you meant the gasket between the manifold and the y-pipe, not the gasket between the manifold and head.

 

haha yeah interesting. I have the same exact problem right now. I installed hooker headers and the gaskets that they came with are kinda bit soft and thick... in other words... throw them out. Get cooper gaskets because it is a way better seal and your bolts will hold on tightly. So untill I install teh cooper gaskets, I ride around and tighten the bolts about once every 2 weeks. I don't know about you guys but that exhaust leak sound bothers the hell out of me. Even if it is only a leak after the y-pipe. I wanna ride around with a nice sound ya know?

 

I bought some Fel-pro gasket but ill try tightening that bolt .... thanks

 

I have a dynomax system and mine makes a big pop if you let off the gas after revving it up, on its way down....I thought that it was normal, but could this mean i have an exhaust leak? It backfires at about the same point every time.