Just wondering if a lot of fire from the exhaust could signify anything damaging.

I was making a hot pass through Deal's Gap (Tail of the Dragon/crazy windy road here in NC/TN that I live and work at) Saturday night, with a couple of locals on sportbikes following. On the initial run they said I was belching 4 foot long flames for the final few miles on deceleration. I can see these in my mirrors at night as well. No popping.

On the run back across, I wicked it up a bit, and they had to lane cross to stay with me. They said at one point the exhaust just "caught on fire" and a flame was sticking straight up behind the car for several seconds, even while I was on the gas. Then it just went out. I thought I saw the flame itself for a second in my mirror, but it was hard to spot with their headlights behind me. They said there weren't any sparks, just fire.

It didn't seem to damage the exterior any, and the muffler doesn't seem any louder like it was damaged. I am running complete 3" exhaust, no cat, with headers and O2 collector, Dynoflash, 650cc injectors, Walbro 255 fuel pump, and HKS intake. I assumed the exhaust was heated enough to cause the belching on decel, but I'm not sure why it burned for so long that one time.

I'm kind of concerned that I may be overspinning/overheating my turbo I guess...I haven't really checked for boost leaks, and I'm not making the torque numbers to match my HP number. (302hp/260tq at the wheels) Al (Dynoflash) seemed to think something wasn't right. I know there is a small exhaust leak at the Downpipe/O2 Collector. I make 22 pounds of boost at 3200 rpm. (stock turbo)

TIA for any input.

 

Are you running a VTA BOV? If so...that is why your car is splitting out fireballs. However, it shouldn't be that big of a flame unless you are running super rich.

Tom

 

Thanks! Yeah I installed a Forge Type RS a couple of weeks ago and haven't picked up a length of hose that will work for me. (long story) I live out in the stix and it takes at least an hour to get to a decent parts store or hardware store.

 

Fireballs are fun! Nawh, you should be ok soon as you lean out your mix and put your BOV to recirculating.

 

Yeah I don't have a problem with the occasional belch, it was the 6-second long flame thrower that worried me. My A/F ratio is good, Al got that straight when he custom Dynotuned me at Top Speed a few weeks ago. I do have a Turbo XS Tuner to install though that will let me keep a better eye on A/F though...

 

My car has shot fire that long before, just running rich, that's all. It tended to do it more frequently as I shifted, but there were occassions the flames just hung out around my bumper for some time. My friend's WW does the same thing, except it discolors his rear bumper a little, but it comes off when its washed. Nothing to worry about. Running too lean would be of utmost concern, tho...

 

Do you have adjustable cam gears?

 

Not installed, I have a set of Fidenza gears and a set of GSC 272/264 cams sitting here to install eventually, but yeah, just stock cams/gears for now.

 

It's a good thing that you found out what is causing this, I've heard that you will emit small flames without a cat, but nothing like what you're describing.


I took my bike out to the Dragon last summer and it was unbelievable!!! I actually bought pics of me and my freinds off your website, great deal and something that helps me remember my trip to the Smokies. I'm hoping to get a couple other EVO owners to take a road trip out there for some 4 wheel fun.

 

mine shoots LOUD fireballs when I slam through gears and im running stock bov.

 

mine always shoots out 7 ft fireballs. I do it to be cool. If i ever shot out only a 6 ft. I would be so dissapointed

 

totally normal if your running vta bov and your rich as hell my car used to do it all the tieme until i got retuned..

 

I installed the HKS SSQ about 2 weeks ago....running it VTA. Its been working fine but do I have anything to be concerned about?

 

Yeah I was running one of those before, and it made the car surge pretty hard, especially VTA. When you lightly roll off the throttle after building boost, you can feel the car buck. That is turbo surge and it's pretty rough on the turbo. Even once I recirculated it, the unit did not vent early enough on throttle lift, and there is no real way to adjust it. I even opened it up and tried crushing the spring a little, but it didn't help. I like this Forge Type RS kit. It costs about the same, and comes with 2 different pistons, 2 springs, and an adjuster knob with a very smooth notch action that allows you to preload the spring and adjust when the valve releases pressure. It's not quite as pimp looking as the SSQV, but the internals are much higher quality.

 

silly me... with a 4 ' flame thrower I would have thought the chance of starting a roadside forest fire would have been a first concern.