1 7/8 or 1 3/4 headers?
01-15-2011, 08:38 PM
#21
Racer
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St. Jude Donor '10
On my 404 stroker, went from 1 3/4 to 1 7/8 with extra porting on LS3 intake, 90 MM TB, and a smaller cam. Gained over 30 RWHP and went up on low end to 400 RWHP at 2750 RPM. If you have any mods or additional cubes in mind, go for the 1 7/8 amd save $$. With a good tune, very little, if any lost, if you already have a H/C mod. Originally, a lot of older posts would have you think a lot is lost down under, but not so with a good tune, good heads, and cam. Basically, you have to have the air flow to make everything work. One of my first mods was a Z06 intake and headers, I lost torque down under with this configuration and untouched LS1 heads. When I added 30# SVOs, cam, and 243 P/P heads, everything woke up with 409 RWHP and 398 RWTQ. If mods are in the future, go 1 7/8, if not, stay with the 1 3/4, Xpipe, and free flow cat backs.
Mike C
Mike C
01-16-2011, 01:13 AM
#22
Melting Slicks
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St. Jude Donor '08
Look at it this way too...if you're going for name brand headers like LG, Kooks, American Racing, etc you're paying at LEAST $1100 new for the set with x-pipe. If you change your setup in the future to FI, or a bigger N/A build it would be nice to have the 1.875" header from the start so you don't ever doubt your self.
If you're purchasing OBX, XS Power or used 1.75" headers then just go for it and don't worry about it.
If you're purchasing OBX, XS Power or used 1.75" headers then just go for it and don't worry about it.
On my 404 stroker, went from 1 3/4 to 1 7/8 with extra porting on LS3 intake, 90 MM TB, and a smaller cam. Gained over 30 RWHP and went up on low end to 400 RWHP at 2750 RPM. If you have any mods or additional cubes in mind, go for the 1 7/8 amd save $$. With a good tune, very little, if any lost, if you already have a H/C mod. Originally, a lot of older posts would have you think a lot is lost down under, but not so with a good tune, good heads, and cam. Basically, you have to have the air flow to make everything work. One of my first mods was a Z06 intake and headers, I lost torque down under with this configuration and untouched LS1 heads. When I added 30# SVOs, cam, and 243 P/P heads, everything woke up with 409 RWHP and 398 RWTQ. If mods are in the future, go 1 7/8, if not, stay with the 1 3/4, Xpipe, and free flow cat backs.
Mike C
Mike C
01-16-2011, 04:19 PM
#23
Burning Brakes
The 1 7/8" headers don't cost too much down low, but you will get more power in the 2500-4500 rpm range with LG Pro 1 3/4" long tubes. With that being said...I went with the kooks 1 7/8"...but they are a PITA to install...If I only knew prior that small of difference in dia. would be that much harder to install. Make sure you get some new f-body gaskets and some heat sox before you start your swap. good luck
01-16-2011, 06:48 PM
#24
Race Director
URBAN LEGEND: You will loose down low with 1 7/8 headers.
Ed Hutchings at VA Speed did some back to back testing a few years ago using the same brand and configuration headers. The 1 7/8 lost nothing down low and picked up from the middle up. Others have PROVEN the same.
You have to be careful when you ask advice on any internet site. So much of what you get back will be "friend of a friend" type "facts"
Ed Hutchings at VA Speed did some back to back testing a few years ago using the same brand and configuration headers. The 1 7/8 lost nothing down low and picked up from the middle up. Others have PROVEN the same.
You have to be careful when you ask advice on any internet site. So much of what you get back will be "friend of a friend" type "facts"
01-16-2011, 10:00 PM
#25
Racer
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St. Jude Donor '10
Kevin,
Right there with you. I ported the same 90MM TB and LS3 intake that I had on my 404 stroker, milled the heads slightly from 9:5 to 1 to 10:75 to 1, and went from 1 3/4 to 1 7/8 LT headers. IMO, I feel the header increase had more than anything else to do with my increases. Both the baseline and added headers were with tunes from 2 well known vendors. In addition, I even went with a small cam, from 231/249 to 231/239. I think the results below confirm the fact that engines with more cubes do benefit from the 1 7/8 headers and there is no loss down under with a good tune.
Mike C
01-17-2011, 03:50 PM
#26
Burning Brakes
I'm going with 1.875" FWIW... kinda bummed that there isn't a OBX or XS Power budget header with the larger primary. It's either Kooks or American Racing for me.
01-17-2011, 05:14 PM
#27
Drifting
Jimbo
01-17-2011, 05:43 PM
#28
Race Director
It's been proven time and time again go with the larger 1 7/8 over the 1 3/4. You don't loose anything down low(dyno proven) and you gain more up top(dyno proven) You guys already posted links so no need to go into a debate. Plus down the road when you add more mods it will only help. Why would you even think twice about thi?. Not sure why people are so stuck with 1 3/4 and then say you loose over from the 1 7/8th FALS. Not most of the time but ALL of the times when your racing your not chugging at 2k in 4th gear. Get that baby to breathe. Nuff said 1 7/8th
01-17-2011, 07:56 PM
#29
Safety Car
I have 1 7/8 ARH on `03 Z06 with CAI & tune & 3 90 gear. & the power increase from 4500 - 6800 [limiter] is very noticable . & it seems a little easier to control wheel spin at lower rpm for me. Very happy with the results.
