After having a Vortech SC installed last week, I noticed a small oily reside on my exhaust tips. Before I had the SC I would get a dry residue every week or so. Is this change something to be worried about or is this a natural byproduct of the FI.

 

Is it really oily?? Or just kinda wettish char...from running too rich. Mine exhuast tips are disgustingly black.

If it is actually oil...then that could be a problem. It is a sign of compression loss in your cylinders. You should get a compression/leakdown test just to be sure. In fact, its not a bad idea for F/I people to periodically get a compression test done. It's the easiest and cheapest check of the condition of your motor.

 

GQ,

After driving from Dallas to Houston (about 4 hours). I noticed about 1/4 of drops worth of oily residue on the bottom of the tip.

Is a compression test something that any shop can do, or should I find one that specializes in FI

 

nope...even your local PepBoys can't screw up a compression test. I hope!

You have me worried..I am going to check my tips right now a report back...hold on.

 

Houston.....you have a problem.

My tips were bone dry...dirty...but dry. I am running about 9-9.5psi on the street, and some nutty testing at 11psi with the Greddy kit.

Get the compression tested ASAP.
If I recall, you are running a 9lb pulley..right?

What does your A/F look like?

Also, check your oil level..if its overfilled, you could get some oil on your tips. Just drain some oil and you'll be fine.

I hope its nothing major.......

Even if it is, I bet the Nissan dealer that installed this will warranty out your motor...they seem mod friendly.

 

After watching my tailpipes for a few days now, I think residue is normal. It is not actually oily, just easier to remove than normal exhaust residue.

I will keep an eye on this none-the-less.

GQ, I will take your advice to get a comp test.

Thanks for the advice.

 

SAME HERE FELLAS....

b-4 the vortech kit, i was nearly 100% dry and clean (part of the post-wheel/caliper wipe is the tailpipe wipe.....yuck!!)

anyway, after the vortech (and custom mapping nonetheless) i get ALOT more carbon residue on the tip lowers..... it actually appears to run over the bottom lip, leaving a stream-like appearance after every ride....

i bet most of this is due to the extremely increased fueling, BUT, the moistness of this is condensation (help me here GQ) or ??? from running the a/c so dang much (in tanden with the blower)

i checked out the feel, and its not oily at all. its a dry carbon-like buildup, VERY similar to my akrpovic exhaust residue, but just thicker and darker....

if the residue appears to be silver (or grey) then its also time to worry (signs of a lean burn)

 

I've just de-carbonized an Intrepid and a GMC Sierra and watched all the crap come out of their tailpipes. Engines burn gas an make water and carbon dioxide and other stuff with it. So, exhaust fumes are moist from the water vapor. It condenses somewhere in your muffler or tailpipe or somewhere and then blows or drips out. It's just carrying the residue buildup out like a stream and that's why it looks like it's dripping.

For a great demonstration, have someone with a biga$$ motor idle their car for a while and then rev it real fast. I've seen a Viper spray down someone walking behind the car before.

The A/C puts more load on the motor, but it's water drips under the car or in the vent ducting.

 

Mant times you can get a black looking wet residue at the exhaust tips...usually it is soot combined with water vapour from the exhaust....especially on a cool morning

 

Yup, I get the stream effect in the morning for a few minutes. When i feel the residue it is wet and carbon-like.....but not oily. If you actually have oil on the tips...could be signs of a problem.

 

H2O is also a byproduct of the Catalyst's chemical conversion IIRC. That combined with the amount of cold mass that the cats are condenses the water vapor out of the exhaust gasses initally. It's not uncommon on a cold morning to see a stream of water fall out of the exhaust tips of cars as they leave a stoplight. Once the cats warm up as well as the rest of the piping the vapor stays gaseous.