WARNING: Track Guys, Check Your Exhaust Systems

[shinoo]

There have been a spate of exhaust failures on the racetrack with stock AND aftermarket systems recently. I am encouraging all y'all to check your systems on a regular basis for problems. Last week, I spoke with 2 owners and know of 3 cars that suffered failures and fires.

Track driven cars generate serious heat build up in the exhaust cavity of the Elise/Exige. The heat shielding does a great job in keeping the trunk and rear grills from melting. Unfortunately there does not appear to be adequate provision to vent this heat. So the net result is that the exhaust components are stressed even further. Couple this fact with the significant amount of engine rotation/vibration and you have exhausts (headers, cats & mufflers) that are breaking. Luckily most people are catching it before too much damage - but some are experiencing fires.

The naked rears that we have been promoting seems to help the heat evacuation issue but is not a cure all. Having a completely flat bottom car has its pluses and minuses. So please be forewarned that your track driven car (even aggressive street) should be checked very frequently.

[Mag]

any cases where aftermarket headers (un-heatwrapped) caused damage? - thanks

[Chili Red]

Took my diffuser off the other day and my exhaust clamp was loose enough that I could move it with my hand. Bolts were about finger tight..

[Boosted2.0]

Ceramic coating is your friend...

[Jean-Paul]

links please. i am experienceingthe sae problems with my stock exhaust system !!!

can you be a little more specific as to wht to check. u mean bolts been loose ?

also what are the + - of removing the rear difuser ?

should we consider also removing the heat shields from the catalytic converter when removing the rear panel you offer?


thx

[loki]

I am one of TWO yellow lotus that caught fire at Thunderhill last Tuesday. the exhaust (stock) failed, came apart, at the link into the muffler(two pipes) and caught the rear clam on fire. Same problem, same place for the other Lotus. Forunately I had an onboard fire extinguisher and damage was minimal, scorched and blackened rear clam and cooked wiring including loss of left rear licence plate light. The other Lotus was not as fortunate and had rather extensive rear damage along with a liberal helping of halon from the track fire truck.
Now I have modified my car over the years and have ITG filter, Katana and no cat on the track so I run Leaded 110. That, plus 84 track days, puts unforseen stress on the stock exhaust system as anyone who modifies their car can expect. It is a whole system so just changing "one or two things" ignores stresses passed on.
That being said, Thunderhill has noted two other Lotus catching fire in a similar manner. It is a weak point and I suggest anyone who tracks rework that joint with better clamps, screws, etc.
Oh, and carry a fire extinguisher, weight be damned!

[LarryB]

Loki- sorry to hear about it and glad you caught it early. One of the things I did about a year ago was to add the ForcedFed engine damper. I've seen and felt how much flex the engine has in it mounts, is that something you had been using?

[Randy Chase]

Photo from Somyunguy

[davecarama]

I may be experiencing one of the early signs. I am getting a vibrating sound when I am letting my clutch out and start moving (it stems from engine vibration, but sounds like a cat or exhaust thing).

Did you notice any symptoms before the fire? Anything that COULD have been an early sign that something may be wrong?

Dave

[loki]

Originally Posted by LarryB

Loki- sorry to hear about it and glad you caught it early. One of the things I did about a year ago was to add the ForcedFed engine damper. I've seen and felt how much flex the engine has in it mounts, is that something you had been using?

No, I haven't. Hoover from Turbohoses (an official Sector 111 installer) feels it is not necessary but I'm open to other opinions. I am tossing that little Lotus around a lot. Something has to give...

[knucklehead]

Originally Posted by davecarama

I may be experiencing one of the early signs. I am getting a vibrating sound when I am letting my clutch out and start moving (it stems from engine vibration, but sounds like a cat or exhaust thing).

Did you notice any symptoms before the fire? Anything that COULD have been an early sign that something may be wrong?

Dave

I just recently started to have this exact issue. Please post what you discover is the problem.

To Loki and Somyunguy, sorry to hear about you cars.

[Murix]

Originally Posted by LarryB

Loki- sorry to hear about it and glad you caught it early. One of the things I did about a year ago was to add the ForcedFed engine damper. I've seen and felt how much flex the engine has in it mounts, is that something you had been using?

So is there thought that this would help with the issue?

[Lotusmotion]

Do you think a "naked" back end (no grills, removal of exhaust heat shield behind the license, and exposed exhaust) would have helped in extinguishing the fire and reducing clam damage?

I track my car, too, and am considering this mod to make visual inspections of the exhaust easier and provide easier access for fire safety reasons.

Thoughts?

[LarryB]

Loki & Murix-

Anecdotally, think it would be something to take a closer look at. Especially with this rash of failures. I've seen how much flex, just from revving the engine, we have. Recall some that have had the engine hit the firewall. Been a while since I've looked at the stock exhaust system don't, recall how it handles that type of movement.

I also have the ForcedFed street header and sport cats, it has couplings that are a lot more tolerant of the engine flex. I'd be interested to hear if any of these failures had been using stiffer motor mounts or aftermarket headers / exhaust for most of the time, that have more flexible mounts then the stock setup.

[Murix]

Sounds like I just got more motivated to buy a few parts I planned on anyway. Extinguisher, damper, and rear panel delete up next. I would rather be safe than sorry and these things have enough other benefits as well.

Fwiw, I can say I have had my exhaust on and off (replaced the stock exhaust) twice over the past few months and at no time did it feel loose. I have 15k miles on the car now.

[Terry]

I have heard of this happening to a supercharged car, but has it happened to a NA car? My lower engine mount bolts (both mounts) all worked loose (on the track) and the resultant torquing of the engine broke the exhaust pipe near the cat, but there was no resulting heat damage. It just got loud really fast.

[cpforyou]

Would Lotus take responsibility for this?

Maybe not track driven Lotus, but the streen driven ones...

It was over 100 degrees in Burbank, CA over the past weekend, and my water temperatures soared to near 220 degrees when exiting a freeway and getting to my destination.

On the freeway, everything seemed normal, with water temperatures just under 200 degrees.

Now, I know that water temperature and exhaust temperature are two different things, but I would like to think that if your water temperature is high, your engine temp is higher, and generally, your exhaust system will be a little hotter than usual.

[Randy Chase]

Originally Posted by Terry

I have heard of this happening to a supercharged car, but has it happened to a NA car? My lower engine mount bolts (both mounts) all worked loose (on the track) and the resultant torquing of the engine broke the exhaust pipe near the cat, but there was no resulting heat damage. It just got loud really fast.

On my car at Buttonwillow at the last WCLM. Rounding a corner, I heard the exhaust get louder. I pulled into the pits and checked it and found that the exhaust had separated from the cat. I did have aftermarket cat pipe and headers. But I can't say for sure that it was not operator error in making sure the clamp was tight enough.

The clamp is a little suspect in how well it clamps.

[Bane]

Holy crap... I'm going to ceramic coat my setup ASAP... I may make this mandatory for the cat/decat pipes I sell also...

Aftermarket headers are generally jammed so tightly into the stock parts that I would never expect to be a failure where people are reporting them. My setup is 3.5 mm larger in diameter then stock so it's a royal PITA to install/remove but at least I can take a little comfort in not having it come apart as easily.

Has anyone had a failure with an aftermarket header that replaces the stock cat pipe also?

[John]

Yes, concur that the OEM exhaust clamps are very poorly designed - I've seen several come loose at the track. Sorry to hear about those of you who caught fire - I have to admit that I have been a bit concerned myself after seeing how I melted the license plate lighting after only 3 track days...