which headers for EB S-XR6? - Page 3 - Ford Forums

TIKFD6 · 10-06-2004, 07:34

Its actually called "Overrun".

psycho chicken · 10-06-2004, 07:44

Overrun can cause backfiring, especially in older carbies, but unburnt fuel igniting is still backfiring.

sxr6man · 10-06-2004, 19:58

Quote:

Originally Posted by p4r4l3l

i do notice it gets up to normal speeds abit better, effortlessly i love it

i rarely push car over 3000-3500 as im not a fan of thrashing, plus i only gots an auto

sounds like the 4499 are the ones to go for then unless somene can really put up a good argument to get the competition ones - 4480's. Keep in mind the rev range i want to get the most benefit from is 1000 - 4000 rpm.

TIKFD6 · 10-06-2004, 21:38

Backfire is Back through the intake.
The popping and or flames on over run is from unburned fuel igniting.
My car used to do it all the time when it didnt have a cat.

nEb · 10-06-2004, 21:55

just a note with extractors you actually seem to lose some a little bit low down grunt but gain more in the higher revs... correct me if i'm wrong. but thats what i noticed. i think because you lose back pressure. so if you want mainly low down power maybe better off leaving it stock?

FoMoCo4eva · 10-06-2004, 22:19

Quote:

Originally Posted by Rollin

nope, thats the fuel burning in the exhaust pipes and not the engine, or comtinuing to burn as it leaves the combustion chamber...i love that sound :)

I love it to..come into a corner, say one that you should be in 3rd; chuck her into second and leave it to decellerate before you turn in and what do you get! -> pop pop pop diddy pop!

Its awesome!

sxr6man · 10-06-2004, 23:18

Quote:

Originally Posted by nEb

just a note with extractors you actually seem to lose some a little bit low down grunt but gain more in the higher revs... correct me if i'm wrong. but thats what i noticed. i think because you lose back pressure. so if you want mainly low down power maybe better off leaving it stock?

which ones r u using 4499 or 4480?

nEb · 10-06-2004, 23:49

i have the standard pacemakers... i.e. not the pacemaker competition ones. they are the same ones in the photo in this thread. i'm not sure if they are 4499 or 4480.

oneredED · 10-07-2004, 00:26

Quote:

Originally Posted by TIKFD6

Backfire is Back through the intake.
The popping and or flames on over run is from unburned fuel igniting.
My car used to do it all the time when it didnt have a cat.

I only have a cat-back and mine does that all the time (popping, not backfing). Does that mean my cat's screwed?

Jared

sxr6man · 10-07-2004, 01:38

[quote=
In the 4499 there are two sets of primaries, 1, 2 and 3 and 4, 5 and 6. This greatly reduces the scavenging effect compared to the 4480.[/QUOTE]

PC, I found this on the Pacemaker FAQ site and it further explains what u were saying. They refer to V8 style headers but I guess the principles are the same for 6CYL, ie: 4 into 1 is same as tuned lenght or race style.

A 4-into-1 design is perhaps the most traditional design. This design is common to the US market and is well used within the drag race fraternity. The basic principle behind the design is that the scavenging effect within the collector cone effects the three remaining pipes (in a V8 half), instead of limiting the pulse to the very next pipe in the sequence. This generally results in a header that performs very well in the mid-range to top end of the engines performace.

A TRI-Y on the other hand splits the firing order evenly and uses the secondary pipes as sequential collectors. This results in generally a greater scavenging effect due to the fact that scavenging is achieved at 2 different points in the header design, firstly at the primary to the secondary collector and secondly to the secondary outlet collector. Generally this improves torque in the lower to mid range perfomance of the engine.
Both designs are usually more efficient than a standard manifold and both offer distinctly different advantages.