Just a note, remember the "power of the square"? Two pipes @ 2-1/4" DIA = 7.95"^2 flow area Two pipes @ 3" DIA = 14.14"^2 flow area BIG difference.
This post got wayyy off subject. My response to the original post (Should i get a SINGLE 3" exhaust?) is YES. Why? Well, it might be overkill for the motor now. Keep in mind, however, that you will probably not stop with exhaust. Sooner or later, you may want to stick some heads, a bumpy cam, or who knows what else onto it? You might lose some torque now, but you will pick up some gas mileage in the process. If we were talking dual 3" pipes, i would say no way...but a single 3" pipe would be like having 2 1/4" dual exhaust (as Rick Book pointed out), which would NOT be too much for a relatively stock motor. FWIW, new camaros come with single 3", and it is quite effective. Make sure it is MANDREL BENT though--my current 2.25" exhaust gets down to about 1" going around the corners--BIG MISTAKE! So i say, to the original poster, GO FOR IT! 3"! As for me, i get my new exhaust put on this thursday! (Whee!!). I am having a 2 1/2" system with an x-pipe put on it, dumped at the wheels. I ordered some Thrush turbo mufflers. Laugh it up, because they're cheap, but i actually know a guy at one of the local supercharger places, and he has a flow bench. He said that, of all the mufflers he's had his hands on (and that's quite a few, mind you), they outflowed everything by quite a bit. Plus, at $17 a pop, i can afford to replace them every two years when they blow out. With dumps they should be relatively quiet too. And, yes, i have a motor that needs 2.5".
I agree, except the original post didn't say SINGLE 3" pipe, he said he has 3" hookups on the headers and wanted opinions if he should stay at 3" all the way back.
Wow...some excellent analysis on the subject...on the Flowmaster chart they recommend 2.5 inch on a 302 that produces between 300-350 HP. Now I cant say my engine produces that kind of HP as I havnt had a dyno done on it. I can say the cam is medium and the only way I have to judge this is by the lope and sound of the engine at idle. Geez I wish I could record it so all could hear...it is awesome. So I think Im gonna go with the 2.5 inch with X-pipe and the flows I have to put on it...and pay particular attention to the bends in the pipe during installation. On the Thrush pipes...if I didnt already have the flows...I would go with the Thrush...I've always liked em and the way they sound...maybe most expensive isn't always best... Thx for all the help guys...lemme know what you think of my decision. Rick
Whoops! that was my mistake actually. One of the other posters said that because of the smog laws they needed to stay with a single exhaust. In that case--definitely 3". For dual exhaust like you want, riporter, 2.25 or 2.5 will serve you nicely (but why not just get 2.5" and work your way into it?). I'm getting a killer deal on my exhaust, $125 back to the axles with dumps, and a top-of-the-line X-pipe. This guy does really good work too. Good luck to you!
Exhaust size. Wow. Lots of discussion on this one. My two cents is just to say I made some 3" tailpipes for mine on Saturday and although it was a pain to get over the axle and out the back between the tank and the shackle on the drivers side, I'm really happy with the way it sounds now (it's been dumps at the axle up till now). 3" sounds great and once I sent it all the way out the back it's even relatively quiet compared to before. As far as 3" being overkill for a small block, If you ever plan on getting curious about nitrous oxide, your engine will appreciate any help it can get evacuating exhaust gasses.
Great talk guys! Always learn something on this board.....or atleast get more opinions. My thoughts on it are.................................................................... open headers, open headers open headers!!!! The louder the better!!!!!!
I made 2.5 exhaust for mine...course I have a bender I had tailpipes ONCE but didnt like all of the heat shielding I had to make to keep the fuel cool
Open headers had horsepower when your carb and setup is dialed for it. Running open headers on a mild motor will probably lean it to the point where you could hole a piston.
More .02 cents (I think I'm up to a buck now). I absolutely HATE hearing a car go down the track with open headers UNLESS IT'S QUICK ! Most of the crowd is embarrased FOR the driver. I ran 7.20's in my STREET mustang with 2-1/2" pipes and 3 chamber FlowMasters. Relatively speaking, it was quiet as a mouse (compared to the open headers). I run the 1/8th and hear a few small blocks running open headers. They run high 7's. By the sound of it, you'd think it was a top fuel at the line. - Until you 'see' it run. Big disappointment. I won't run my Maverick down the track until it has mufflers on it (and yes, because it's a nitrous engine, it will have 3" pipes). There are plenty of mufflers out there that don't waste h.p. - some may claim to even gain a little. Do yourselves a favor guys, ALWAYS run mufflers - your fans will appreciate your quiet car outrunning that loud sob beside you. Thank you. The floor is now open to further debate.
Rick; I tend to disagree with you, not on the technical side, but on the noisy side. When I go to the races, the noise, smells (nothing like burned nitro or H&H racing gas) and sights are a big part of the experience. When I was running a car, the sound of the car told me what I had to do to get it right, and the spectators liked the sound of it (1977 Maverick with 514). I can't imagine going to the races with cars that are quiet, no matter how fast they are. Just my .02. Earl
Amen Earl! I agree with Rick in one part, I hate to see a 8 second car going down the track sounding crazy loud! But for me, I know when I am there by the smell of racing fuel, burnt rubber and open headers, open headers, open headers!!!!:bananaman :bananaman
Aww jeez, now i feel embarassed! I took my car down to the track and ran it open header just to see what it would do without exhaust (my exhaust right now is very restrictive). Actually shaved about a half second off my time, which is why i'm getting a new exhaust made up tomorrow. I'm sure i looked like a moron doing it, but i sure had fun
CACollo It will be interesting to see what the differences are between your old exhaust, open headers, and the new system.
