this should probably be posted under "track" or "DE", but i know that it will get viewed more here. last weekend, at Sebring, i melted a plastic fuel vapor vacuum line and the plastic bracket that holds the O2 sensor. has anyone else had this happen? my engine water temps were normal, but oil temps were high (about 265). the fuel vapor line caused a check engine light. not a problem in itself, but....what can be done to lower under hood temps? i've already planned on an oil cooler. i have a 15% pulley and CAI installed. would a freer flowing exhaust, colder plugs, ECU tune....help me?

 

On that note, does a freer flowing exhaust help keep down engine/oil temps at all?

 

i don't know.....just grasping at straws here. i'd have to think that the highest underhood temps are at the headers (maybe wrong) so exhaust flow might help...

 

There are many options which will help you. Some of these options cost more than others and are more involved as far as instalations.

One of the first, and best things you can do is get an m7 Aerogel pad which lays over the header and keeps heat from permeating into the engine bay. The part is cheep (~$130) and the install is incredibly easy.

Another mod along these lines which has shown some effect in reducing engine bay heat is getting a ceramic coating on the header. This is not an easy route though. The coating can cost as much as $150 to $200 depending on where you have it coated and you need to remove the header and put it back in. This mod will compliment an aerogel pad, but it is not necesary once you have a pad.

A third way, although there is some dispute about it, is to get an m7 180 degree thermostat. On my car, I have moticed a marked decrease in engine bay temps after installing this. The install is difficult, however, as you will need to remove your airbox and a couple other parts to get to the thermostat which is mounted on the lower right side of the head.

Both the aerogel pad and the thermostat are available at Custom MINI Shop which has great prices and top notch customer service. They would be more than happy to help you work out your excessive heat problem. Their website is www.customminishop.com.

Hope I was of some help

-Blake

 

Sorry, but exhaust flow will not help significantly here. I have seen EGTs of close to 1200 degrees which is going to permeate into the header no matter what. The main goal is to stop the heat from permeating from the header into the engine bay.

 

The O2 sensors are on the header and not in the upper engine compartment. Are you talking about an O2 sensor connector melting? Air temps in the engine compartment shouldn't get hot enough to melt any of the plastics. It's possible to melt things if they come in contact with hot metal parts, the header for example.

Steve

 

i went to realoem.com and found the following part #'s for melted bits:
#11787535229-pipe clip: this plastic piece holds the o2 sensor in place near the cat.
#16126766123-vacuum pipe: this piece returns gas vapors into the induction system so that they don't escape into our precious ozone.

looking at these pieces will give you an idea of how high temps i was experiencing. they melted from ambient temps, not contact w/ hot metal!

help, please......my next track day is in less than three weeks....BTW i was running down a bunch of 996's when this occurred! does that matter?

 

It's very possible to char or melt plastic pieces near the exhaust when the car is run hard. I have a blackened oil pressure sender connector from this, and it's a good six inches from the pipes. The fix is pretty simple, wrapping the part or shielding them with aluminum foil.

As for lowering the temps, this is difficult. What's happening is the cats and the header are basically glowing almost orange when really pushing things, especially if the ECU thinks the IAT is too hot and richens the mixture to protect the engine. The super rich mixture comes out of the exhaust still ablaze and burns along the length of the headers. The catalyst has to deal with it after that, and only adds to the heat. You can purchase thermal wrap to cover the pipes in, but this essentially insulates the pipes themselves and makes them run hotter still. Such temps can cause the pipes to fatigue and crack.