Fiberglass Temperatures with SE tips or Single Tips

[lancer360]

I have my Larini "SE" tip exhaust installed and have some questions regarding the temperatures. I went out for a good drive and came back and checked the temperature with an infrared sensor. The tips measured around 350F and the fiberglass was around 120F. I just reinstalled the exhaust with heat wrap installed. It was pretty cool out, around 45F. I'm worried that later in the year when it gets warm and I do a track day or two that the temperature will get too high. Has anybody with the Larini "SE" tips or any of the single tip exhausts with the rear panel still installed checked their temperatures? What is considered a safe maximum temperature for fiberglass? 130F? 150?

[Devious]

It really depends on the resin used. By itself, fiberglass cloth and mat can handle very high temps. It is the resin that limits the heat. Does anyone know what resin is used by Lotus?

If you want to reduce the heat radiated from the exhaust, coat it with a thermal barrier coating. Techline Coatings sells coatings for DIY.

[lancer360]

I have already put a heat coating on the exhaust, but it defeats the purpose of the polished tips to coat them and that is what is closest to the fiberglass. It is the paint that I'm most worried about and secondary the resin. I know the fiberglass will withstand very temps.

[Devious]

Then what you want to know is the temp that you will start to damage the paint?

[lancer360]

Since you are being so specific, at what temperature will any damage occur to the rear clam. Has anybody else checked the temps of the rear clam with a through the grill style exhaust like the 2ubular or Arqray?

[pixlpush]

I have the Larini "SE" tip exhaust system as well and have also noticed that it gets quite hot especially on the drivers side. I had it out at the track last August when the ambient temperature was close to if not over 100 degrees F. It got hot enough that the reflector on the Euro Grills melted and humg down like goo. I have the stock heat shield in place with cuts in it to clear the exhuast tips. Even though it was hot enough to melt the reflector, something that has happened to me again on the street, the paint and clam seemed fine. Even the starshield behind the rear wheels came out fine. So in my experience it definitely gets hot, but not problems with the paint, at least not yet.

here's a linke to my previous post about the melted reflectors:

http://www.elisetalk.com/forums/show...lted+reflector

[lancer360]

I adjusted the heat shield with a hammer where the reflector bracket sits so that it isn't touching, but I still figure I will take them off at track events. Luckily autocross events are so short, that it doesn't build up heat any more than normal driving. If you have a track event coming up, if you wouldn't mind checking the temps I would be interested in comparing data. I'm looking at doing my first track event in May.

[pixlpush]

I actually cut the reflector bracket with a dremel tool so it wouldn't sit on the cat heat shield, it still melted. Taking the reflectors of at the track is the way to go as you suggest. I just did a track event on Friday and don't have another on the calendar yet . I've been meaning to pick up an infrared thermometer as well. I'll let you know what I find. Other than the refelectors I haven't had any problems.

[JnC]

Lotus engineering group is obsessed with weight. They eliminate as many parts as they can or have one part serve many roles.

Lotus intentionally designed the Elise with the heavy heat shielding for a reason. And the preforated rear grill serves two important roles: it's a grasscatcher to prevent flammable bits from coming into the muffler area and it acts as a radiator to conduct and dissipate heat away from the clam.

That said, I'm not aware of any melted clams yet. But I think if Lotus could have left bits off, they would have done so. I do recall that the original design had open grills on either side of the taillights; this was later filled in as the hot engine air flow was causing the clam to melt.

The other concern I have is coatings. Hypothetically, let's say you get an aftermarket header with a heat coating and remove the header heat shield too. The heat is still there and it's got to go somewhere. The header can't dissipate as much heat and it goes downstream. So the cat/muffler gets hotter. And if the exhaust is heat coated, there's going to be a lot of heat at the tips.

Somehow you've got to sink that heat.

[xtn]

Originally Posted by JnC

The other concern I have is coatings. Hypothetically, let's say you get an aftermarket header with a heat coating and remove the header heat shield too. The heat is still there and it's got to go somewhere. The header can't dissipate as much heat and it goes downstream. So the cat/muffler gets hotter. And if the exhaust is heat coated, there's going to be a lot of heat at the tips.

Somehow you've got to sink that heat.

No you don't. Unless you think you are getting close to actually melting the metal exhaust parts, there is nothing wrong with letting all the heat exit the tip into the airstream.

xtn

[lancer360]

The European version of the Elise does have the tips exiting through the grill. I'm not aware that they have change that. I'll keep an eye on it and hopefully some more people will post there experience with rear clam temperatures. If it does appear to be a problem, I'll either look at fabricating a simple metal shield to go around tip for track days or go with a panel eliminator kit or the challenger grill. Many people have done that and are not having any problems with heat.

If you anybody has picture of the heat shielding that is done from the factory on a through the grill exhaust, I would appreciate it if you could post it or send it to me.

Thanks!

[lancer360]

Originally Posted by xtn

No you don't. Unless you think you are getting close to actually melting the metal exhaust parts, there is nothing wrong with letting all the heat exit the tip into the airstream.

xtn

I think the point JnC was making is that insulating the header and/or exhaust will raise the temperature of the exhaust gases at the tip, thereby making the tip hotter and possibly compounding the problem of the clam getting too hot near the tip.

[JnC]

Originally Posted by lancer360

The European version of the Elise does have the tips exiting through the grill.

But that is sold thru Lotus Group only for the S2 Elise/Exige 00-04. Those cars had the Rover VVT engine, not the Toyota mill. IIRC the header is on the opposite side compared to the Toyota. It's longer as it has to go under/around the engine: longer header = more surface area = cooler exhaust.

[JnC]

Originally Posted by lancer360

I think the point JnC was making is that insulating the header and/or exhaust will raise the temperature of the exhaust gases at the tip, thereby making the tip hotter and possibly compounding the problem of the clam getting too hot near the tip.

Bingo. The heat has to go somewhere.

[MitchT]

the sector 111 kit is the ticket, I have the arquay, and do a lot of track time, the tip of the unit get so hot it has lost it chrome and now is blue and black, but I have no clam melting or paint problems, I left the heal shield on top and in the rear and modded the rest. The stockgrill unit does keep stuff off the rear but it also keeps heat in, air flow is the key.

[xtn]

Originally Posted by lancer360

I think the point JnC was making is that insulating the header and/or exhaust will raise the temperature of the exhaust gases at the tip, thereby making the tip hotter and possibly compounding the problem of the clam getting too hot near the tip.

Uderstood. But I strongly suspect MOST of the heat absorbed by the fiberglass is radiant heat from the pipe. The exhaust gasses are mostly not blown against the fiberglass, right?

xtn

[lancer360]

Correct, but the hotter the tip is made by the exhaust gases means more radiant heat.