500RWHP stock bottom end, hydraulic roller, M6 LS1/LS6 recipe?
01-05-2012, 04:26 PM
#62
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I think we need to have more input on a 2" primary header like the one offered by KOOKS. It has a 3.5" out and you can combine it with their 3.5" Y-pipe which snakes very well under our cars especially on the driver's side where clearance is at a minimum.
The question is, what will a 2" primary header do to a head and cam LS1?
The question is, what will a 2" primary header do to a head and cam LS1?
01-05-2012, 04:57 PM
#63
6600 rpm clutch dump of death Administrator
I saw that you had bumped the 1 3/4 vs 1 7/8 thread. The bottom line is a 2" header is way to big for a 346 inch motor unless you have a short primary and lots and lots of RPM. A 346 turning 8000 rpm calls for ~27" primary and 1.948" tube.
The general calculation for ideal tube size are
Header pipe length (in inches) = ((850*(360-EVO))/RPM – 3
Header diameter (in inches) = ((cylinder. disp. * 16.38 / ((hdr len + 3) * 25))) * 2.1 .
Software like Pipemax will also help you make more definitve calculations.
The general calculation for ideal tube size are
Header pipe length (in inches) = ((850*(360-EVO))/RPM – 3
Header diameter (in inches) = ((cylinder. disp. * 16.38 / ((hdr len + 3) * 25))) * 2.1 .
Software like Pipemax will also help you make more definitve calculations.
01-05-2012, 10:14 PM
#64
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I saw that you had bumped the 1 3/4 vs 1 7/8 thread. The bottom line is a 2" header is way to big for a 346 inch motor unless you have a short primary and lots and lots of RPM. A 346 turning 8000 rpm calls for ~27" primary and 1.948" tube.
The general calculation for ideal tube size are
Header pipe length (in inches) = ((850*(360-EVO))/RPM – 3
Header diameter (in inches) = ((cylinder. disp. * 16.38 / ((hdr len + 3) * 25))) * 2.1 .
Software like Pipemax will also help you make more definitive calculations.
The general calculation for ideal tube size are
Header pipe length (in inches) = ((850*(360-EVO))/RPM – 3
Header diameter (in inches) = ((cylinder. disp. * 16.38 / ((hdr len + 3) * 25))) * 2.1 .
Software like Pipemax will also help you make more definitive calculations.
01-06-2012, 09:20 AM
#65
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
01-06-2012, 03:01 PM
#66
Maybe this old thread will help. https://ls1tech.com/forums/generatio...o-results.html
01-06-2012, 04:01 PM
#67
6600 rpm clutch dump of death Administrator
So, here is what I would say to that. Ther eis more to comparing headers that just primary tube size. Look at the bends, the collector, etc... it all adds up.
If you were to take a well built, well executed 1 7/8" header and compare it to a poorly built 1 3/4" header I would expect the 1 7/8" header to do well against the 1 3/4" even on something like a 346.
I'm going to go back to some discussions we had on Corvetteforum over headers in say 2003 since most of the products have been superceded now. At the time, you had few choices in the Corvette world. Lou @ LG was building a 32" primary header with a nice merge collector. Now the design of the header at that time was basically a TPIS header that had the tubes lopped off at the bottom, and had been streteched out to get to 32", and then a race collector added. In fact the original pair used to be hanging on the wall at Lou's shop. The only real issue with those headers is the intial tube bends coming out of the heads were a bit sharp since they were based on the TPIS headers.
Then Kooks started building headers. The Kooks headers at that time had a really nice initial exit, and they had nice routing. The issue with them (IMHO) was primary length and collector. The primaries were too short, and the collector was just a plain collector (too short, no goilet, etc...). I suggested to them what I'd like to see and even drew a picture of it, but that drew the ire of George at Kooks.
I guess what I am trying to say is that you see a lot of tradeoffs in headers that go beyond just primary size and tube length. I think the best numbers I have seen out of a set of headers on an A-B swap was a set custom built by John B for his car.
What you see today is most folks assume they go up in displacement, etc... and it makes more sense to buy 1 7/8" up front instead of having to buy new headers if they make a change. Also, with stock cubic inches jumping up from 346 to 376 and 427 inches, you are closer to needing a 1 7/8" to begin with. So, most folks are willing to give up some low end and midrange.
If you were to take a well built, well executed 1 7/8" header and compare it to a poorly built 1 3/4" header I would expect the 1 7/8" header to do well against the 1 3/4" even on something like a 346.
I'm going to go back to some discussions we had on Corvetteforum over headers in say 2003 since most of the products have been superceded now. At the time, you had few choices in the Corvette world. Lou @ LG was building a 32" primary header with a nice merge collector. Now the design of the header at that time was basically a TPIS header that had the tubes lopped off at the bottom, and had been streteched out to get to 32", and then a race collector added. In fact the original pair used to be hanging on the wall at Lou's shop. The only real issue with those headers is the intial tube bends coming out of the heads were a bit sharp since they were based on the TPIS headers.
Then Kooks started building headers. The Kooks headers at that time had a really nice initial exit, and they had nice routing. The issue with them (IMHO) was primary length and collector. The primaries were too short, and the collector was just a plain collector (too short, no goilet, etc...). I suggested to them what I'd like to see and even drew a picture of it, but that drew the ire of George at Kooks.
I guess what I am trying to say is that you see a lot of tradeoffs in headers that go beyond just primary size and tube length. I think the best numbers I have seen out of a set of headers on an A-B swap was a set custom built by John B for his car.
What you see today is most folks assume they go up in displacement, etc... and it makes more sense to buy 1 7/8" up front instead of having to buy new headers if they make a change. Also, with stock cubic inches jumping up from 346 to 376 and 427 inches, you are closer to needing a 1 7/8" to begin with. So, most folks are willing to give up some low end and midrange.
01-14-2012, 12:27 AM
#68
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So, here is what I would say to that. Ther eis more to comparing headers that just primary tube size. Look at the bends, the collector, etc... it all adds up.
If you were to take a well built, well executed 1 7/8" header and compare it to a poorly built 1 3/4" header I would expect the 1 7/8" header to do well against the 1 3/4" even on something like a 346.
I'm going to go back to some discussions we had on Corvetteforum over headers in say 2003 since most of the products have been superceded now. At the time, you had few choices in the Corvette world. Lou @ LG was building a 32" primary header with a nice merge collector. Now the design of the header at that time was basically a TPIS header that had the tubes lopped off at the bottom, and had been streteched out to get to 32", and then a race collector added. In fact the original pair used to be hanging on the wall at Lou's shop. The only real issue with those headers is the intial tube bends coming out of the heads were a bit sharp since they were based on the TPIS headers.
Then Kooks started building headers. The Kooks headers at that time had a really nice initial exit, and they had nice routing. The issue with them (IMHO) was primary length and collector. The primaries were too short, and the collector was just a plain collector (too short, no goilet, etc...). I suggested to them what I'd like to see and even drew a picture of it, but that drew the ire of George at Kooks.
I guess what I am trying to say is that you see a lot of tradeoffs in headers that go beyond just primary size and tube length. I think the best numbers I have seen out of a set of headers on an A-B swap was a set custom built by John B for his car.
What you see today is most folks assume they go up in displacement, etc... and it makes more sense to buy 1 7/8" up front instead of having to buy new headers if they make a change. Also, with stock cubic inches jumping up from 346 to 376 and 427 inches, you are closer to needing a 1 7/8" to begin with. So, most folks are willing to give up some low end and midrange.
If you were to take a well built, well executed 1 7/8" header and compare it to a poorly built 1 3/4" header I would expect the 1 7/8" header to do well against the 1 3/4" even on something like a 346.
I'm going to go back to some discussions we had on Corvetteforum over headers in say 2003 since most of the products have been superceded now. At the time, you had few choices in the Corvette world. Lou @ LG was building a 32" primary header with a nice merge collector. Now the design of the header at that time was basically a TPIS header that had the tubes lopped off at the bottom, and had been streteched out to get to 32", and then a race collector added. In fact the original pair used to be hanging on the wall at Lou's shop. The only real issue with those headers is the intial tube bends coming out of the heads were a bit sharp since they were based on the TPIS headers.
Then Kooks started building headers. The Kooks headers at that time had a really nice initial exit, and they had nice routing. The issue with them (IMHO) was primary length and collector. The primaries were too short, and the collector was just a plain collector (too short, no goilet, etc...). I suggested to them what I'd like to see and even drew a picture of it, but that drew the ire of George at Kooks.
I guess what I am trying to say is that you see a lot of tradeoffs in headers that go beyond just primary size and tube length. I think the best numbers I have seen out of a set of headers on an A-B swap was a set custom built by John B for his car.
What you see today is most folks assume they go up in displacement, etc... and it makes more sense to buy 1 7/8" up front instead of having to buy new headers if they make a change. Also, with stock cubic inches jumping up from 346 to 376 and 427 inches, you are closer to needing a 1 7/8" to begin with. So, most folks are willing to give up some low end and midrange.
But my new question is concerning 1 7/8" headers. Are they the best suited option for a strong head cam stock bottom LS1 or are the 1 3/4" better suited for that application.
01-14-2012, 02:02 PM
#71
I'll chime in since I'm giving a full effort to reach 500whp. I'm going to run stepped. maybe triple stepped with a full port at every weld. The steps will be a 5 degree taper, not a blast one pipe into another. The ports off the chamber will run straight with the head port angle, not the flange angle and might be as small as 1 5/8". The collectors will be top notch with runners connecting in firing order to attempt a swirl and will neck down and back out. I think If I wanted to run just 1 3/4" only with the rest being the same, the headers will flow well for my goal. I'm off to my head porters now to try and improve some mid lift numbers.
