When upgrading your set up to make more power.Ex from the common 500 hp build up to the 600 plus aluminum head build. should you pay attention to exhaust pipe diameter. I currently run a torque tech 3" sytem with x-pipe and 3" dynomax ultra flo mufflers. In an 83 buick regal, I see that some are runing 3.5 headers back and reducing after the x-pipe to the 3 inch sytem. Judging by how much was gained by going to 2 1/8" headers over the 2". would this be a recommened next up grade? Oh and how about Merge collecters ?o No:
i have a 520 h/p 462 and run 1 7/8 headers with a 3 1/2''' collector threw a 2 1/2'' mandral bent system. My car runs the same E.T. with the headers uncapped. I believe the x pipes are great for cars with stock exhaust manifolds, but i have not seen eney proof that they help a car with headers.
It depends on what you want out of it. The 3" pipes will be fine for what your doing. I have 3" pipes with an X on my GS. The hardcore GSM guys are in the 9's with 3" pipes. I think 3" pipes are borderline "too loud" for a street-driven-only car. If you're only racing, go with 3 1/2" and turndowns in front of the rearend. It's up to you, but don't complain that a 3" exhaust is slowing you down. Some of us know better! :laugh: :3gears: Have fun.
Kelly, I was refering to the exhaust pipe size. My set up judging by my et is in the neigborhood of 500 plus. With aluminum heads more compression lighter pistons 9375 1050 domy. 600 to 650 hp is very possible. at which point your 1 7/8 headers and 2.5" exhaust and my 3" would be a restriction. By the way. My x-pipe did help me drop my et. dont know how much because I made two changes at once. They do work. Several people I've seen at the track confirm this. I will say all x- pipes aren't created equal. I run this one. http://members.aol.com/xforcefast/hotrod-june2001.htm http://members.aol.com/xforcefast/hotrod-june2001.htm
i would think that a 3'' system would help you, because you are at least 100 more h/p and are looking for 10's also turning more rpm, i just run the stock 800 Qjet and usually shift at 6000 but go to 6500 sometimes for fun,i can rev to 7000, but that is out of my cams range and i am running modified stock rods. i would like to hear some results with some same day runs on the X system then open it up and see if there is a difference in E.T., also the 3'' systems are to loud for me on the street. just my 2 cents
The 3 is better flowing than the 3.5 IMHO. Rememebr that as you increase pipe diameter you reduce backpressure AND flow velocity, while increasing cooling rate of the exhaust (cooler flows slower). For pulsation flows this is even more important. I think you'd actually be oversized at 3.5" and lose some power.
3" will be just right, and will easily take the right combination well into the 9's. 3.5" is also heavy, so factor that in as well.
One thing I don't understand is why people run a 3.5 collector and a 3 inch (or smaller) exhaust pipe. When you down size your collector you are not getting the negative pressure wave and not taking advantage of the scavenging effects of the exhaust system. You would not run a step header that started with a 2 1/8 and transistion down to a 1 7/8. When you run a collector with extensions equalling about two feet in length you pick up power. Collector length is more critical that people think it is and by down sizing the pipe in less than a foot from the header pipes you are loosing power. I know that you might think that that by going to a smaller collector you would loose power but you are in essence doing the same thing with the 3.5 collector into the 3 inch pipes. With a 3 inch collector and a three inch pipe the exhaust flow would be less turbaulant. When exhaust gasses transition to a larger pipe size or the end of an exhaust system they send a negative pressure wave back up the exhaust system (this is where the term scavenging comes from). The first negative wave happens when your pipe terminate into the collector. Then the next typically happens the end of the pipe. I like x pipes and they better simulate a 180 degree header by "sharing" negative pressure waves to each cylinder bank. They also create another transistion area and help "smooth" the exhaust flow. The reason that most engines do not loose power by downsizing after the x pipe is that the negative pressure waves are weaking at that point and the pipe diameter is kept to a sufficient size to still be able to carry the volume of air coming through it, not to metion the exhuast gasses are less turbulant at this point. The first negative pressure wave (where the header pipe terminate into the collector) is the strongest and the last wave (at the end of the exhaust pipe) is the weakest and the least amount of influence on the power output. One last bit of info. All Dynomax Ultra Flo (straight through design) mufflers use the same core. What this means is that the 3 inch muffler and the 4 inch muffler use the same internal diameter. This helps with the 3-3.5 exhaust systems since it creates a larger transistion area and sends an "extra" negative pressure wave back up the exhaust stream. The Dynomax Ultra Flo mufflers are the best flowing until you get to the 4 inch muffers then the Magnaflow units will are only slightly better (maybe not enough to ever be noticed). BTW this is not intended to bash anyone, just giveing my thoughts. :TU: Later, Bart
Jeff I had to read my post over again but I still don't see where I was complaining that 3" exhaust is slowing me down. Every exhaust company I asked has always stated once you go 550 hp and over you should start looking at going to the 3.5. I find it very hard to believe that most of the 650/700 hp buick owners are only running thru 3" exhaust. I know that the're 9 second cars with 3" systems out there I just think it would be easier to obtain with 3.5" with the power out put I plan on making. I based my question on post I've read going from 1 7/8 to 2" headers pick up 1/10 and mph.A more recent post stated there was an 30 hp gain going from 2" to 2"1/8 headers. I feel that larger pipes would help get that hp to the ground.If I'm wrong please some body point me in the right direction.
