Will a few pops & bangs hurt?

[soldave]

Have been following a tuning thread on another Evo forum and the discussion turned to getting the car to make a couple of pops and bangs when you come off throttle; nothing too severe but just something a little different. Advice was offered that if you retard the timing in the lowest load levels of the timing map and possibly richen the fuelling a little at those points, then you can get a few pops as combustion will occur when the exhaust valve is open. It was said that there won't be complete combustion in the exhaust unless extra air is added so no damage will occur.

Just wanted to tun it by you guys though and see what you thought about this idea.

 

[toojung2die]

It has little or nothing to do with tuning a DSM. That kind of engine behavior indicates to me that vacuum or boost is leaking somewhere. I've read about getting the exhaust gas to burn or back fire to keep a turbo spooled in rally cars. Not something I would personally desire. When I hear a pop out the exhaust I start looking for trouble.

 

[gsxtasy]

Why?

 

[toojung2die]

Why?

Because I'm using the stock 2G MAF and it does a good job of measuring air taken into the engine; including air recirculated through the BOV, and delivering the correct amount of fuel. It's been my experience that when my exhaust pops and backfires or the engine stumbles at WOT I'm going to find a leak in my intake somewhere (or a tank of bad gas). Other tuners with more radical turbos, fuel management and tunes than me may find the symptoms described by the OP normal but I don't. My engine runs smooth under no load and heavy load. I think that is desirable. I'd like to hear from someone with a different viewpoint.

 

[gsxtasy]

Because I'm using the stock 2G MAF and it does a good job of measuring air taken into the engine; including air recirculated through the BOV, and delivering the correct amount of fuel. It's been my experience that when my exhaust pops and backfires or the engine stumbles at WOT I'm going to find a leak in my intake somewhere (or a tank of bad gas). Other tuners with more radical turbos, fuel management and tunes than me may find the symptoms described by the OP normal but I don't. My engine runs smooth under no load and heavy load. I think that is desirable. I'd like to hear from someone with a different viewpoint.

No no, I was asking why to the OP. Why would you WANT it to pop and stuff? I agree with you, if mine is doing that, something isn't right. Sorry for the confusion.

 

[Defiant]

I'd probably fix the air leaks in the exhaust as a first step.

 

[gsxtasy]

I'd probably fix the air leaks in the exhaust as a first step.

Am I missing something? Isn't he asking how to make it pop and bang? Not how to stop it from doing it? I'm confused...

 

[Defiant]

Sorry, I never thought anyone would be asking such an inane question here.

I should have known.