Another Exhaust Problem

[DPViper]

Last year I had an exhaust leak in my Corsa track exhaust that caused paint blisters. I got the sill repainted (twice), new clear bra put on the entire sill (twice), and a new Corsa exhaust. I also wrapped the exhaust with Roe exhaust insulation - lots of the Gen 2 guys have used the wrap to help with heat. It was a real pain chasing down and fixing the problem.

Now the sill is cool until I park the car. After 5 minutes sitting in the garage the sill gets very hot - way too hot to touch. Is this normal? I never noticed this before but it could of been happening before I put on the Roe insulation. The car had the Corsa when I bought it so I don't know how hot the car would get with a stock exhaust. I'm thinking of buying a surface thermometer to see how hot it is.

I want to get the heat down because I'm concerned it will damage my clear bra but I don't want a loud exhaust that drones. Someone suggested I hollow out the 2nd cat. Does that work? Will it make the car louder? I like the sound I have now. What about removing the 2nd cat? I dread removing the sills and lining up the exhaust again - I've done it so many times some of the sill screws are stripped! I can live with the existing heat if it is normal and won't hurt the clear bra. Thanks for any suggestions and/or comments!

 

[SylvanSRT]

removing the cats will make the car louder and a little cooler. the corsa system and most others for that matter are not designed to use the heat wrapping. it seems to make sense that when you park that it gets hotter, all the heat trapped under that insulation/wrap then leaks out from under it. i have the corsa system and have a significant reduction in heat since the install. my suggestion would be to remove the heat insulation wrap,that way the heat is constantly leaving the system instead of being held against it and under the wrap. i hope it works for you, i have also read that the insulation may be detrimental to the cats and cause them to overheat way above designed operating temps, causing failure.

 

[Nader]

I have the same set up with the Roe Insullation and have had no issues at all with heat. After drviing the car aggressively the sills are warm at most. The sills do get warmer after shutoff since there is no more air circulation and heat soak comes into play but in mo way should they be hot enough to burn you. in fact mine will get warmer as the cars sits but I still able to keep my hand on them without getting burned.

 

[Nader]

I have the same set up with the Roe Insullation and have had no issues at all with heat. After drviing the car aggressively the sills are warm at most. The sills do get warmer after shutoff since there is no more air circulation and heat soak comes into play but in mo way should they be hot enough to burn you. in fact mine will get warmer as the cars sits but I am still able to keep my hand on the sills without the heat being uncomfortable.

 

[ulllose]

I have the corsa track with all cats installed and after driving on a 75-80 degree day the side sills will be 140-150 degrees towards the front of the sill and around 100-110 towards the back of the sill this is after the car sits for a few minutes in the garage. I have checked this with my IR thermo. This is a huge reduction in heat towards the back of the sill from the stock exhaust.

 

[DPViper]

Thanks for the replies. Great idea Ulllose. Did you also measure the temps before you changed to the Corsa? Has anyone else measured the temps of their sills with a IR thermometer? I am going to buy a thermometer I would like to compare my readings to others with the same and different set ups. My first goal will be to see if my heat soak is typical or if there is something else going on. Thanks!

 

[Nader]

I can guarantee that the sills with the stock exhaust were hot too the point that they would physically burn you if you touch them. I have some scars to prove it.

 

[Racer Robbie]

I have the atro side exhaust system with random cats on my car and the whole system is wrapped. I have over 13,000 miles on this system with zero problems. I can put my hand anywhere, inside or out, on the side sills and not get burnt. Also I can put my bare foot on the aluminum dead pedal on a 90 degree day. After the car is sitting for about 15 minutes I do get some heat soak inside the car but if you leave the windows open an inch the heat rises and goes out the window.


Robbie

 

[DPViper]

Well I broke down and bought an IR Thermometer ($50 at Pep Boys) and after some very spirited driving, the maximum temp on the outside of the sill (beside the 2nd cat) was 185 degrees and occured 15+/- minutes after turning off the car. It has been 45 minutes and it is still 165. I have the Corsa and Roe Exhaust Insulation. Does this sound normal? If I go to the track, I'm sure the temp will go higher. Thanks in advanced.

 

[DPViper]

I forgot, my son shot the IR up the exhaust and it registered 561 degrees! Thanks

 

[PatentLaw]

You are close to boiling there. I agree with SylvanSRT on the heat wrap. You are directly channeling heat from the block down the exhaust and there is no further flow of fluid to remove the elevated temperature condition. The heat wrap holds it in longer. At least you know that the heat wrap works, and that it was installed very well. You just are not liking the unintended consequences of it. Women in pantyhose watch out for that one!

Stupid solution.... if you don't want to take the car apart......buy a large fan for your garage and turn it on when you park inside. It should help alot and not cost you that much money. For other parking areas, just live with it. Oh, and don't park over leaves or grass.

 

[DPViper]

Thanks PatentLaw - a fan could be an easy solution.

I was reading the Gen I/II forum and some owners had sills that were in the 200 to 250 degree range. One owner reported 300 degrees! I would appreciate any Gen III owner reporting their sill temps and/or what sill temp they have heard is "normal". Anyone know what temp it takes to burn the paint or yellow the clear bra? Thanks for your help.

 

[steve911]

I too, have experienced side sill temps as mentioned above. It got alot better after I put on the mopar performace exhaust, and even better yet after I gutted the secondary cats.

Gutting the cats took about an hour after I took the exhaust off. No cutting or welding involved. Just a flat bar with a beveled edge, a hammer, long needle nose pliers, and oh yeah, a good arm to swing the hammer.

Car sounds alot better too.

 

[DPViper]

Update: since nobody had a direct comparison between an exhaust with and without Roe insulation, I removed the insulation from one side and left the other side intact. (I know - I'm neurotic).

Both sides were cool immediately after aggressive driving. After 5 minutes the noninsulated side was 160 degrees and the insulated side was 130 degrees. After 15 minutes the noninsulated side had dropped to 140 degrees and the insulated side increased to 150 degrees. After 45 minutes the noninsulated side was 120 and the insulated was still 140 degrees. Bottom line: the noninsulated spiked a little higher/quicker and cooled quicker, and the insulated side had a slightly lower high temp but held the heat much longer.

Which is better? Thanks for your comments. Doug

 

[ulllose]

dpviper--

Great research.....

With your numbers i'm really second guessing my numbers. I was going by memory but now i will have to check it again. I'll post in a couple of days

 

[SylvanSRT]

your experiment proves what my thoughts were on the exhaust wrap and heat retention

 

[wormdoggy]

Look it .

Being in the insulation business I can tell you that insulation is meant to retain heat or cold depending on the application. We use insulation on a variety of different applications with temperatures exceeding 2000 F. The main purpose is to protect individuals from scalding themselves on the hot pipes or ducts. As of course other reasons.

It is important to know that the insulation will allow the heat to dissipate a lot slower consequently maintaing the metal at higher temps. as you have found out.

I have always been a proponent of non-insulated exhaust unless some can convince me that the additional heat strain will not collapse the walls of the exhaust. In high temp. applications the wall cavity thickness is increased to allow for additional heat retention. I suspect that your current exhaust was not meant for the insulation wrap. I would certainly call the manufacturer but I can tell you right now , they will probably recommend you take it off.

I have access to all kinds of insulation from mineral fibre to ceramic blanket that I could easily use for this application. I choose not to for the reasons mentioned above. I have seen the walls collapse and its not pretty.

Get high flow cats and you should be fine.

Just my two cents.

Patrick

 

[valentine_viper]

Have you checked your A/F ratio? Excessive exhaust temps are a symptom of a too lean mixture (or possibly a too rich mixture if you are getting raw fuel in the exhust system where it then burns off). Besides creating a lot of unnecessary heat, a bad A/F ratio can also cause a whole host of other problems, like burned pisons, valves and rings. If it's bad enough, you can even melt the heads.