My friends Evo shoots huge flames out the exhaust and makes a loud fire cracker sound. He tells me it only happens when he goes over 5k rpm and when the rpm starts to drop it makes the noise. His HKS Vpro is programmed to do this. The noise is so loud its like setting off a M80 fire cracker...with my windows rolled up and about 50 feet away following him it scared the crap out of me. I heard its bad for the car but also helps throttle response... is it true

 

Something tells me his car isn't going to like flames shooting out of it's ***.

I know I wouldn't

 

isn't his car just backfiring? he's catless right?

 

Anti-lag. Very bad for turbo's longevity.

 

He does have the stock cat on. It happens every single time when he wants it to. Besides killing the turbo are there any benefits when using it? I wonder how fast your turbo will be shot from using this anti lag?

 

As the name implies, anti-lag totally eliminates lag. It keeps the turbo spinning at full speed even if you lift off the throttle. So the very second the throttle is opened (i.e. you press the gas pedal) again, turbo is already at full spin. No need to respool.

Rally teams use this because they can afford to change to brand new turbos after every single event. It kills the turbo much faster but by exactly how much I honestly have no idea.

I'm also not sure about the benefits of using this on a road car other than to look/sound cool.

 

It could just be a rich condition after he lets off the gas. It dumps gas and BANG!

A friend of mine w/ a turbo integra did this. It had a side pipe and no cat though.

 

sounds like someone has that initialD "backfire" system.....lol

 

+1

If he didnt have the HKS unit, then it would be unburnt fuel getting ignited in the exhaust stream, usually happens with a straight pipe...

 

Yes it could be.

But after reading threadstarter's comments (on the sound of this 'backfire') I'm still inclined on anti-lag. It is much, much louder than a normal backfire.

 

Yeah i have anti-lag on my Wrx rally car it eats stock turbos J/K. I have the same stock turbo for two seasons. Anti-lag works down low in R's to keep the turbo spinning at all times. It adds extra fuel and fires the spark late when the valve is open. The pressure created by the explosion spins the turbo. It does add a lot of heat to the exhaust.

It doesn't sound like he has anti-lag since it is up in the R's. Just a unproperly tuned car

 

the bang was so loud I thought something happened to his exhaust like it blew up or something

 

i'm guessing you just never heard a car backfire before.

 

If I could take a video of my 2-step @ ignition hard cut with my exhaust cutout open with a decibel reader, you could get a true idea of "loud" backfires. =]

 

do it do it