Header size question?
#1
TECH Veteran
Thread Starter
iTrader: (12)
Join Date: Dec 2004
Location: Friendswood, TX
Posts: 4,137
Likes: 0
Received 0 Likes
on
0 Posts
Header size question?
Looking to buy headers for my car. I'm sure y'all have seen my post about the OBX headers. Quick question... Are you guys running 1-3/4 or 1-7/8 headers??
What kind of power is the 1-3/4 good to? I don't want to have to buy headers twice. Sooner or later, it will be a minimum heads/cam bolt-on car so prob in the 450rwhp range. From what I understand, at 500hp, the 1-3/4 become restrictive. Should I run 1-7/8 incase I add nitrous or get mod crazy or should the 1-3/4 be fine?
What kind of power is the 1-3/4 good to? I don't want to have to buy headers twice. Sooner or later, it will be a minimum heads/cam bolt-on car so prob in the 450rwhp range. From what I understand, at 500hp, the 1-3/4 become restrictive. Should I run 1-7/8 incase I add nitrous or get mod crazy or should the 1-3/4 be fine?
#2
TECH Addict
iTrader: (2)
The 1 7/8 should make equal low & mid-range torque and more horsepower even on a stock motor. Assuming the cost is about the same, the only advantage of 1 3/4 headers is they have fewer clearance issues in the engine compartment.
Based on standard engineering gas flow formulas a 1 7/8 piping system will flow 19.5% more than a 1 3/4 piping system of the same design and length. So the difference is not huge.
Based on standard engineering gas flow formulas a 1 7/8 piping system will flow 19.5% more than a 1 3/4 piping system of the same design and length. So the difference is not huge.
#3
TECH Veteran
Thread Starter
iTrader: (12)
Join Date: Dec 2004
Location: Friendswood, TX
Posts: 4,137
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for the info man! Just wonder why majority of guys seem to run the 1-3/4 setup then? Price is almost the exact same (within $30) and if the 1-7/8 flows better and makes the same torque but more horsepower on the high end, it seems foolish to buy the 1-3/4 over the 1-7/8 option.
My thinking is this though...
Even though they both go to a 3" collector, the fact that the rest of the exhaust is only 2.5" means they would both flow the same in the end anyway unless you made the entire exhaust 3"... right? At that point, it seems like the 1-7/8 would actually have a benefit to it but until then, i couldn't see the slightly larger size being an advantage unless the rest of the exhaust could keep up with it.
Maybe im wrong but thats just my thinking.
My thinking is this though...
Even though they both go to a 3" collector, the fact that the rest of the exhaust is only 2.5" means they would both flow the same in the end anyway unless you made the entire exhaust 3"... right? At that point, it seems like the 1-7/8 would actually have a benefit to it but until then, i couldn't see the slightly larger size being an advantage unless the rest of the exhaust could keep up with it.
Maybe im wrong but thats just my thinking.
#4
TECH Addict
iTrader: (2)
Thanks for the info man! Just wonder why majority of guys seem to run the 1-3/4 setup then? Price is almost the exact same (within $30) and if the 1-7/8 flows better and makes the same torque but more horsepower on the high end, it seems foolish to buy the 1-3/4 over the 1-7/8 option.
My thinking is this though...
Even though they both go to a 3" collector, the fact that the rest of the exhaust is only 2.5" means they would both flow the same in the end anyway unless you made the entire exhaust 3"... right? At that point, it seems like the 1-7/8 would actually have a benefit to it but until then, i couldn't see the slightly larger size being an advantage unless the rest of the exhaust could keep up with it.
Maybe im wrong but thats just my thinking.
My thinking is this though...
Even though they both go to a 3" collector, the fact that the rest of the exhaust is only 2.5" means they would both flow the same in the end anyway unless you made the entire exhaust 3"... right? At that point, it seems like the 1-7/8 would actually have a benefit to it but until then, i couldn't see the slightly larger size being an advantage unless the rest of the exhaust could keep up with it.
Maybe im wrong but thats just my thinking.
Last edited by Darkman; 06-17-2011 at 08:52 PM.
#5
TECH Veteran
Thread Starter
iTrader: (12)
Join Date: Dec 2004
Location: Friendswood, TX
Posts: 4,137
Likes: 0
Received 0 Likes
on
0 Posts
Oh I see. Well thanks for breaking it down for me. Makes sense now!
So is 1-3/4 plenty enough up to a certain hp? Like say 500rwhp? I know 1-3/4 is still a big upgrade from factory.
So is 1-3/4 plenty enough up to a certain hp? Like say 500rwhp? I know 1-3/4 is still a big upgrade from factory.
#6
TECH Addict
iTrader: (2)
The clearance issues with the larger headers can be important if the car is a daily driver since those clearance issues can translate into melted wires, connectors, starters, and engine mounts. You also have do some bending to install the larger size in the V (steering column). Overall in the V, the larger size may not be the best choice unless you are going big (maggies, heads, big cams and such), or building a track oriented car.
Your call.
#7
TECH Veteran
Thread Starter
iTrader: (12)
Join Date: Dec 2004
Location: Friendswood, TX
Posts: 4,137
Likes: 0
Received 0 Likes
on
0 Posts
I see. Well mine is a daily and I plan to do a nice heads/cam combo and that's about it. Maybe a little laughing gas later but nothing too huge. I think 1-3/4 might be my best bet to avoid clearance issues.
Trending Topics
#11
TECH Apprentice
Join Date: Sep 2010
Location: Southern MD
Posts: 366
Likes: 0
Received 0 Likes
on
0 Posts
Yeah I had the same issue. On kooks website they said that the 1-7/8 header is for extreme use... ie heads/cam/maggie etc.. if that's ur plan I think the 1-7/8 will be a good fit. I personally got 1-3/4 kooks headers because I only plan to cam it only.. but like the guys said earlier, its your call.
#12
TECH Enthusiast
iTrader: (12)
The clearance issues with the larger headers can be important if the car is a daily driver since those clearance issues can translate into melted wires, connectors, starters, and engine mounts. You also have do some bending to install the larger size in the V (steering column).
Also, when installing headers of any size, a starter shield/insulator should always be used.
#15
header diameter
I was under the impression (not sure why) that 1 3/4 were generally for motors that would not be supercharged, while the wider diamters were more appropriate for forced induction systems. Someone told me, acutually more than one person told me this. Great thing about being newbie, research can be much more anecdotal. When does newbieism cease? When does responsibility commence? I listened to all you forum folks and freaks and a few salesmen and my V runs like the MF'ing space shuttle! Yes-1 7/8 pipes.