need headers so confused
TECH Resident
Joined: Sep 2007
Posts: 793
Likes: 0
From: Phoenix,AZ
everyone i have known with long tubes have said that they felt they had more top end power rather than low end. my buddy had a 91 z28 and added hooker super comp headers ory and a borla adj. catback and he dropped from a 14.1 to a 13.7 in the quarter and he also started beating other guys cars on the top end on the freeway that he previously had lost too in freeway runs. He said the car felt way more powerful in the higher rpms.
everyone i have known with long tubes have said that they felt they had more top end power rather than low end. my buddy had a 91 z28 and added hooker super comp headers ory and a borla adj. catback and he dropped from a 14.1 to a 13.7 in the quarter and he also started beating other guys cars on the top end on the freeway that he previously had lost too in freeway runs. He said the car felt way more powerful in the higher rpms.
i am almost 100% positive you have this backwards, i just installed my long tubes and got my exhaust welded up and it feels slower from about idle to 2500rpms but much faster from their on up.
i think long tubes moves your peak torque up and shorties will move it down. mids obviously keep it in the mid section.
i think long tubes moves your peak torque up and shorties will move it down. mids obviously keep it in the mid section.
Originally Posted by David Vizard
To predict what primary size will be best for a specific motor, you must know where you want the engine to develop peak torque. If the existing torque peak is at a bit lower RPM than you prefer (typical in under-cammed or stock motors), it can be "bumped" a bit by increasing the primary diameter. If the torque peak is too high (motor is "peaky", with no range and poor recovery from gear changes), the peak can be adjusted down by using a smaller pipe. A change of 1/8" in the primary diameter will raise or lower the peak torque RPM by 500 or so.
This factor slightly overlaps the effect of primary pipe length, but the pipe length generally will not change the peak torque or the RPM at which it occurs. A length change has the effect of improving the torque on only 1 side of the peak by "borrowing" it from the other side. A shorter pipe improves the torque after the peak (reduces it at lower RPM), preventing the curve from flattening out so quickly as speed increases. A longer pipe extends the torque curve backwards to improve the engine's flexibility, at the expense of after-peak torque.
This factor slightly overlaps the effect of primary pipe length, but the pipe length generally will not change the peak torque or the RPM at which it occurs. A length change has the effect of improving the torque on only 1 side of the peak by "borrowing" it from the other side. A shorter pipe improves the torque after the peak (reduces it at lower RPM), preventing the curve from flattening out so quickly as speed increases. A longer pipe extends the torque curve backwards to improve the engine's flexibility, at the expense of after-peak torque.
You felt like you lost low end torque, (and you did), when you switched to long tube headers because the primary diameter in the headers is significantly larger than that of stock exhaust manifolds. The larger primary diameter raised the torque peak.
If we're going to compare apples to apples, (two exhaust headers that have equal width primaries), then the one with the longer tube will have more of the torque under the curve stacked below the peak every time.
TECH Resident
Joined: Sep 2007
Posts: 793
Likes: 0
From: Phoenix,AZ
yeah dude totally cant wait to see how she runs, i guess my stock z28 wont be givin you a little trouble on the freeway anymore huh lol. As for the flowmaster i like the sound if your wanting a mellow tone for driving and idle but you know me im all about loudass rasp and screamin so its either gonna be the gmmg for me or the slp loudmouth 1.
I had a feeling I'd see a response (or three) like this one, which is why I said "all other things being equal."
You felt like you lost low end torque, (and you did), when you switched to long tube headers because the primary diameter in the headers is significantly larger than that of stock exhaust manifolds. The larger primary diameter raised the torque peak.
If we're going to compare apples to apples, (two exhaust headers that have equal width primaries), then the one with the longer tube will have more of the torque under the curve stacked below the peak every time.
You felt like you lost low end torque, (and you did), when you switched to long tube headers because the primary diameter in the headers is significantly larger than that of stock exhaust manifolds. The larger primary diameter raised the torque peak.
If we're going to compare apples to apples, (two exhaust headers that have equal width primaries), then the one with the longer tube will have more of the torque under the curve stacked below the peak every time.
so if the primaries were the same diameter and the length was just increased it would give more low end torque? thats interesting to know.
Staging Lane
Joined: Feb 2006
Posts: 86
Likes: 0
From: Boise, Id
Fu?? it im going to cut through all the red tape and use my stock system for emmissions testing then take it off and put Lt's and an offroad y pipe on.yeh it's a little annoying having to do all that work each year. but it will save the headache of having to find an emmisions legal LT setup. and some money. the non emmisions set ups are a lot cheaper
TECH Fanatic
Joined: Nov 2007
Posts: 1,745
Likes: 18
From: Lansing, MI via Bowling Green, KY, Dalton GA, Nashville, TN & Atlanta, GA
I think I would rather move to a non-emissions state, or spring for an emissions legal setup, than swap from headers, to stock manifolds, back to headers every year. If you have a nice garage, with a lift, it might not be so bad, but dang. I dread waxing my Jeep once each year before winter.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Five Reasons the Camaro Was the Most Pivotal Player in the Pony Car Wars 2.0
Brett Foote
10 Reasons the LS7 Is GM's Most Extreme Naturally Aspirated V8 Engine Ever
Verdad Gallardo
im going to cut through all the red tape and use my stock system for emmissions testing then take it off and put Lt's and an offroad y pipe on.yeh it's a little annoying having to do all that work each year. but it will save the headache of having to find an emmisions legal LT setup. and some money. the non emmisions set ups are a lot cheaper
Or find yourself a "friendly" inspector and put on LT's.
