so im just finishing up my t5 swap and in order to get the tranny out we had to cut the exhaust which was fine considering my headers were already cracked and my entire exhaust system was ghetto rigged(ill have to post pictures because it was pretty funny, in a sad sort of way). anyways i will be finishing up in the next few days and my new headers wont be here yet. i wanted to just drive it as it is (cut off at the end of the headers) but i have been told to be careful because cold air can get into the engine and crack the heads(?). just wondering if i will be ok for a few days or if i shouldnt drive it at all.

 

Other getting you a ticket or cabon monoxide poisoning from fumes coming in the car I don't think there is anything to fear.

 

yes, cold air can get in there and hurt the engine. I would not do it unless you have a minimum of 3-4 feet of pipe, and it will be LOUD as hell

Think about this for a second...front engine race cars still have enough pipe to get the exhaust behind the driver, so the fumes dont effect the driver, even sprint cars do that, and they only run for about 15 miles at a time

 

its gonna be ridiculously loud and slow. you will easily lose 15 hp because of the lack of back pressure. i was switching out an exhaust on my inline 6 bmw and it was louder than most muscle cars yet slower than all of them

 

I have been hearing that theory about getting cold air in and cracking the heads for a long time now. I'm old ya know. However, it doesn't make logical sense, since the hot exhaust gases are pouring out of those headers. How, tell me, can cold air get in while the hot gasses are escaping? However, I wouldn't run the engine for more than a few minutes while in the driveway. Not only will the neighbors boo you, the local fuzz will be glad to have you contribute to the local tax base.

 

It seems to me that cold air would only be able to get in if you had an exhaust valve stuck open.

 

Thank you redstallion. That sounds logical. I used to run open headers on early 50's cars with open headers and never had a problem with a cracked head from cold air getting into the combustion chamber. I don't think it is possible. If I am wrong, break it down and tell me how.