cooked a side sill

[uvbnbit]

Local, small town July 4 parade yesterday, I carried a pageant attendant. Slow, 2 mile'ish loop. Engine temps were fine, but footwell seemed quite hot. When parade was over, I could really smell burning coming from passenger side. Silver side sill is now brown, bubbled threshold, plastic "viper" strip is a bit distorted/melted from heat. I grabbed my hard-top, got out on road as soon as I could to cool down the sill. Even the door and rear tire were too hot to touch. I just knew any minute it was going to flame up. Will be carrying extinguisher with me from now on.

-Hi-flow cats are 2 yrs old with less than 4000 miles on them.
-I'm lowered 1.5" (limited air flow?)
-passenger side only, driver side was fine
-WBO (driver side) stayed in 15.5-16.5 range during idling through parade
-no sill vents in front or rear.....yet.

Could it be the heat shield is out of place? Lack of air flow?

I just reset PCM after IAC install a day earlier and only had 20 miles on test runs and start/stop cycles.
Could idling/creeping along for that long after a PCM reset be bad?
Lean mixture cause overheat situation on cat?
Why only one side?

Asking for thoughts on possible causes.
pic to follow (on phone)

[daveg]

Sure that cat isn't plugged? Equal amount of exhaust coming out both sides?

[uvbnbit]

Wouldn't think it would be clogged with that low of mileage. Rear tips look same.

[stuntman]

Im surprised the heat worked its way to the door and tire. Pull off the sills and see if the factory shielding collapsed onto your exhaust which would transfer a lot of heat to the chassis and sill. If so, I would rip out all of the factory shielding which is poorly mounted to the chassis with staples and replace both chassis and sill side heat shielding entirely with HPStickyShield from www.heatshieldproducts.com -use 1/2" thick Heatshield Armor on the bare pipes to take the heat reduction another big step further.

Airflow is key to cooling and the factory design has really poor airflow. Cutting a hole in the front of the sill behind the front tire and using mesh would greatly improve cooling. But it will be fighting an uphill battle if the factory shielding is touching your exhaust.

0.02

[daveg]

I agree but one never knows. I would have shot it with my Infrared Thermometer to see what the actual temp difference was.
Where was the burning paint, in the front or rear of the sill?

[uvbnbit]

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[daveg]

What components are located in the sills besides hi-flow cats? Whats confusing its only one side. May want to rip that sill off and inspect. Look for leaks, insulation etc...

[stuntman]

What exhaust are you running? That looks like its behind the cat and could be a leaking joint from the cat to exhaust.

[uvbnbit]

B & B, Roe hi flows. Checked all band clamps and joints few weeks ago. Pipe and cats only.
Sill will definitely be coming off for inspection.

[uvbnbit]

I'll be doing the vents next.

[daveg]

Run it with sills off. May want to take off both and use Infrared Thermometer while idling a while if you find no leaks.

[Camfab]

Seems the Row cars have always had an issue with melting cats. If the supercharger has inherent fuel control issues, your going to continue to melt cats. As an FYI the factory heat shielding is not stapled to the chassis. The staples are holding the seems of the stainless together. Most aftermarket heat shielding will fail in short order and is inferior to the factory stuff. The only proven shielding is the incomel shielding which runs in the three to four K range for the whole kit. It's sold by a company called ATP, I believe Dan Craigin had a hand in that. Using inferior aftermarket shielding will increase the likelihood of burning your car down. As also stated, the key to cooling the sills is getting air in and out of them. Remember if the car has fueling issues inherent to a design flaw in the supercharger, no insulation will help. The CAT just becomes a blow torch trying to burn off fuel.

[99RT10]

Start by getting rid of the cats. Straight pipe only and make it easy to swap in/out cats if you have to be inspected every 2 years. used 3" band clamps. The Roe does hate cats. Dogs are ok though..............

[uvbnbit]

Was catless for 6 yrs. Fumes and yellow rear bumper wore me out. I've had zero problems with fuel control.
I'll check some of the mentioned possibilities. No more extended idling if possible..

[VYPR BYT]

Good time to wrap some heat shielding now that you're tearing into things for repairs.

[stuntman]

My apologies. How are the chassis side heat shielding attached? I have not removed mine yet. I will be using HPStickyShield for the entire length when I get around to removing my sills again.

I don't think those ATP inconel heat shields have any insulation like HeatShieldProduct's biosoluable silica, so the ATP only acts adds an additional layer of air for insulation while Heatshield Products also has 1,800*F continuous-capable insulation which reduces 70% of the radiant heat. There are many cheap insulating products out there to avoid, but HP has some pretty good stuff.

I missed the OP car having a Roe, you really need metal cats or straight pipes since ceramics aren't known to last very long in FI applications.

[ICPREY]

-WBO (driver side) stayed in 15.5-16.5 range during idling through parade

It's possible you had a overfueling issue on the passenger side without knowing it. I vote a clogged cat. I would run it without the sills on and shoot it with a thermal gun like mentioned above.

[Sybil TF]

Start by getting rid of the cats. Straight pipe only and make it easy to swap in/out cats if you have to be inspected every 2 years. used 3" band clamps. The Roe does hate cats. Dogs are ok though..............

I bought his cat deletes. I really wonder if the stink smell may be from a rich tune and cats plug easy...I hate cats, Sorry to hear.

[Eco-Friendly]

Maybe a misfire on that bank putting raw fuel in the cat causing it to overheat..

[RTTTTed]

I suggest it's a good time to change the 02 sensors and use the nonfoulers on the rear sensors.

Chip, with no cats and after I put up the the stink (and the wife complaining about it every time) I had my stock PCM tuned by Chris Jensen and 'Poof' no more stink. Car runs much better and I put the 2001PCM back in the car.The 2006 PCM is great because it doesn't have the misfire codes, but with higher hp the faster PCM works better.

I did have a problem that is probably related to yours with the right side cumping fuel when I was off throttle. Flames out the rear exhaust burned the paint off my rear bumper. Right bank plugs were all dark brown. I changed the 02 sensor on that side and change spark plugs. My wideband is on Driver's side so I'm pnly guessing that the sensor fixed it. It's in the bodyshop for another month or so to fix the Deer damage.

[uvbnbit]

No CEL on the mis-fire possibility. Rear O2's are zip-tied up out of the way. I'll see if I can tell a difference in exhaust pressure coming out as well as check for clogged cat.
Stunt, I"m thinking the Roe Hi-Flows are metallic, not ceramic.

[uvbnbit]

Even discolored rear of sill and melted/distorted fender well...dang, that's hot!
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[dave6666]

Blown, with cats, with factory insulation, and without heat problems. Ventilation and a path for air circulation is the answer.

[uvbnbit]

I knew you'd done that and was waiting for that to show up for reference. Well done, and thanks for sharing. I'll be inspecting heat shield, injectors, LT and STFT, O2, etc to rule out any fuel delivery issues to the right bank. More air flow regardless of findings too.

[Camfab]

Stuntman, your right, the ATP uses air as an insulative layer. However, inconel will flat out not crisp and fail like 304 stainless. If the insulation your referring to is as effective as you say, it will ultimately destroy the cat and stainless exhaust post CAT. 304 is great stuff, but will fail if it's continually super heated. So ultimately the ATP stuff is thin and works great with a vented sill system, mainly because there is room for air to move within the sill. Dave's solution is a good one because you can put your priceless stock pieces away and cut into the much less costly fiberglass pieces.

Clearly the Vipers have always had an issue with this area, but add a Roe to the mix and the CAT's meltdown. This is a known issue with that blower. It's obvious why that system would never qualify for CARB certification.