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Thread: SR20VE 4-2-1 "budget" header

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Posts: 1,071-1,080 of 1,123
2009-07-14 03:04:44
#1071
Originally Posted by snickers
This header loses 10hp @ 8000rpm with a 2.5" choke over the 2.25". with a 2.375" choke the header makes 3more WHP @ 7500rpm but looses about 5-8lb ft TQ everywhere up to 7000rpm..


This is charles response on going with a bigger collector.
2009-07-14 04:14:35
#1072
Originally Posted by snickers
This header loses 10hp @ 8000rpm with a 2.5" choke over the 2.25". with a 2.375" choke the header makes 3more WHP @ 7500rpm but looses about 5-8lb ft TQ everywhere up to 7000rpm...

I know how to make more power and improve upon this header but it costs about $380 more and I CAN NOT gaurantee the fitment on an SE-R. There is more room to build it on a P10 chassis and make it fit better for more power so thats how I built the better header.


So how much more power/tq would that header make for $380 just curious.
2009-07-14 04:31:34
#1073
i have a p10......
2009-07-14 04:32:45
#1074
Originally Posted by HKS
i have a p10......


Want to test it for us?
2009-07-14 14:07:39
#1075
well the stainless steel version of the budget header that is true equal length ( or atleast very very close) and has full burns merge collectors, and the correct secondary length and rear collector transition straight length, makes a good deal more than the normal budget header. This is on a pretty well built VE with a lot of money in it. That motor made about 7lb ft more TQ average from 5000-6800rpm and +8whp @ 7800rpm. That header was $1550. I am basing that mild steel price off of the stainless ones that I have built.

going with the final merge with a larger choke of 2.5" does kill power everywhere. you are merging sequential firing cyliders from 2" to a 2.5" size pipe... there is too much volume and this causes the exhaust gasses to expand too quickly and lose the directed flow path. Sort of like running a formed collector on a large 4-1 header. the gasses get "dumped" into the collector after the primary tube with no sense of direction to lead the gasses out.

The smaller choke ( or correct choke) allows the gasses to keep their velocity up as they merge and exit through the last collector. this helps pull a good low pressure on the collector after the last exhaust wave which helps scavenge gasses as well from the next firing cylinder.
2009-07-14 15:05:48
#1076
hey charles on spray painting the header with high heat ceramic paint do u have to spray the inside also? I already did the outside and came out looking great. But someone told me to spray the inside also but thats kinda hard.
2009-07-14 15:09:11
#1077
Originally Posted by MAYIMBEZ
hey charles on spray painting the header with high heat ceramic paint do u have to spray the inside also? I already did the outside and came out looking great. But someone told me to spray the inside also but thats kinda hard.


The inside will just flake off...... I wouldn't try to paint it.
2009-07-14 15:11:16
#1078
thats what i thought too...
2009-07-14 15:39:29
#1079
yeah, you would have to spray and coat all of the inside then bake @ 400 deg for a few hrs.
2009-07-14 15:49:49
#1080
^I like the company you linked me two. I'm going to have them do a alternator housing for me to match my header.
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