Exhaust question

i took off my stock cat-back exhaust off of my 98 trans am,..didnt have time and wont have time till this weekend to put on the new one..just wandering having the exhaust off shouldnt hurt the engine or will it? or create any problems for the next couple of days while its off?
one thing is for sure...i have scared a lot of ricers so far while its been off...lol
Thanks

wont hurt your engine,most drag cars run open headers to gain that extra hp or two... but you now just have all that hot exaughst just dumping right out under your car so you'll probly have a warmer engine compartment then usuall..

exhaust gases will be prone to come right up into your "Cab" of your car. so don't ya know sit too long some where and breath in the pretty stuff. Just be careful.

I'm envious of how awesome your car must sound with the cat back off! NOT FAIR!
Jake

wont hurt your engine,most drag cars run open headers to gain that extra hp or two...
This doesn't normally work out so well for a street car. I know from first hand experience.

Stock y-pipe should still be on right?
Won't hurt anything.

Street cars need the exhaust for back pressure. Open header drag/race cars have modified engines that accomodate an open header exhaust...and even that is still a tuned system to the engine...

I've always been curioius what the back pressure does. The valve springs close the valve. Is it possible that is'a marketing ploy> "OF COURSE YOU NEED TO BUY OUR CAT BACK, YOU CAN'T JUST USE STRAIGHT PIPE, YOU NEED UM, WELL, SEE, THE, UM, YOU KNOW, THAT, SUPER, BACK PRESSURE YA, YOU NEED YOUR EXHAUST TO NOT FLOW AND WE KNOW EXACTLY HOW TO KEEP IT FROM NOW FLOWING JUST RIGHT, THAT'S IT, NOT FLOWING JUST THE RIGHT AMOUNT SO THOSE VALVE'S CLOSE, CAUSE THOSE SPRINGS, THEY AREN'T SUPPOSED TO DO THAT, AND WELL, YA, FLOWMASTER CAT BACK 299! ALL THE BACK PRESSURE YOU CAN DREAM OF."
In real life, it is extremely commmon practice to buy an exhaust cut out and put that on your exhaust for the drag strip, so you can have completely openn exhaust and increased flow and dare i say some power, but nothing crazy. if you notice, airplane engines, (i know this cause my good friend is a certified airplane mechanic) have no exhaust, they',ll have headers, manifolds what have you, but your not going to see and pipe after that, if they have resonators or mufflers or anything like that, it is only because the owner wants them. I know several people who build engines, everyone say that back pressure is a marketing ploy,, simply put, if you didn't need back pressure you would never need an exhaust company to charge you overly exhorbitant rates for you pipes. But that's just my opinion. Hope this helps somewhat. Feel free to flame me, i have it coming, lol.
Jake

Okay...my experiences.
Open headers...big time loss of low end power. Still driveable, but it could get rough. Noticed a bunch more cam surge with just headers as well.

Open y-pipe....louder. I didn't notice a power increase/decrease over the Loudmouth.

No manifolds....Never ran this way. Thank god. Couldn't do it in a 4th gen. Start your car on fire. This is where people can ruin the valves. It can easily suck cold air back in...

I've always been curioius what the back pressure does. The valve springs close the valve. Is it possible that is'a marketing ploy> "OF COURSE YOU NEED TO BUY OUR CAT BACK, YOU CAN'T JUST USE STRAIGHT PIPE, YOU NEED UM, WELL, SEE, THE, UM, YOU KNOW, THAT, SUPER, BACK PRESSURE YA, YOU NEED YOUR EXHAUST TO NOT FLOW AND WE KNOW EXACTLY HOW TO KEEP IT FROM NOW FLOWING JUST RIGHT, THAT'S IT, NOT FLOWING JUST THE RIGHT AMOUNT SO THOSE VALVE'S CLOSE, CAUSE THOSE SPRINGS, THEY AREN'T SUPPOSED TO DO THAT, AND WELL, YA, FLOWMASTER CAT BACK 299! ALL THE BACK PRESSURE YOU CAN DREAM OF."
In real life, it is extremely commmon practice to buy an exhaust cut out and put that on your exhaust for the drag strip, so you can have completely openn exhaust and increased flow and dare i say some power, but nothing crazy. if you notice, airplane engines, (i know this cause my good friend is a certified airplane mechanic) have no exhaust, they',ll have headers, manifolds what have you, but your not going to see and pipe after that, if they have resonators or mufflers or anything like that, it is only because the owner wants them. I know several people who build engines, everyone say that back pressure is a marketing ploy,, simply put, if you didn't need back pressure you would never need an exhaust company to charge you overly exhorbitant rates for you pipes. But that's just my opinion. Hope this helps somewhat. Feel free to flame me, i have it coming, lol.
Jake


Mr. Luos touches on the issue of back pressure. Yes, you do need it, especially on a street car because you dont normally run your street car at 5000 rpms. You get drag strip power because most of that run is at the high range of the rpms. At low end, you're going nowhere...the car cant get out of its own way. Same concept in the intake. Long skinny runners = good low end, crap high end. Short fatty intake = good high end, crap low end...

i've ran old cars with no pipe's, and they run good, i know if you try and run a new ricer engine like that you won't even be able to start it, but not sure about the newer firebird engine's....

What do you mean by no pipes??

Manifolds, or no manifolds?

i mean just straight off the headers

So there are pipes off the heads?

i mean just straight off the headers
Pipes off the headers??
Or just open headers?

ya, open headers, i've run old big blocks like that before, no cat, muffler, pipes, etc. but i'm not sure about the newer engines, the newest engine i've ever worked on is the 78 pontiac 350 i got right now, i used to be a mopar man, i played with a 68 440, and a 72 400, but all this new stuff is wierd to me, so i'm not 100% how it all works.

As long as there is a header/manifold off the head...it should be fine.

If you check the link in my sig...that was my LS1 with nothing but headers on it. Ran good....but lacked some SERIOUS power down low.

"back pressure" i think is a bad word to use, i think its more of a suction that the gas creates as it leaves. IF the car was running open headers it wouldnt have the suction power that the tubes would other wise create...? correct me if im wrong, btw...

the theory is that when gas moves to the back, it pulls the air around it with it (since its going at high velocity) and as it exits it pulls more exhaust with it...