279whp with just intake / exh on The Roadster
Thanks!
01-04-2009, 07:33 PM
#83
We got the headers done yesterday and finally dyno'd them today. What a long few days it has been trying to get these finished up!
This first set is actually for a racing team, so we mocked them up on our race car and they are infact not designed to work with the factory Y-Pipes, contrary to what we are designing these for.
We got a lot of footage and tons of research done, along with testing of our new exhaust, and old exhaust. We tested the following combinations:
SGM Longtubes vs. Coast Fab Longtubes
SGM Longtubes w/ dual 2.5exh vs SGM Longtubes + SGM 3.5" Exhaust
SGM Longtubes + 3.5" Exhaust vs. Coast Longtubes + dual 2.5" Exhaust.
I will have dyno sheets along with a video and more photos at some point tommorow, I'm just updating before I go to bed, still so excited from today's events! The race car has never sounded so amazing (similar to the roadster, only a bit louder and much more lumpy and deeper - due to the Nismo cams. It also revs like a superbike because of our tilton clutch and flywheel).
Here is a breakdown:
The larger primaries and collectors in our SG headers caused a small loss of torque below 4000rpm (about 5-6ft lbs) in return for a tradeoff of about 8-10ft lbs of torque above that everywhere, raising peak power from 300whp to 312whp, and peak power gains above 15whp in the 6000rpm region. Remember, this is compared to another set of long tube headers, simply by changing the size of the pipes and collectors you will pivot the torque curve about its peak. Compared to stock exh manifold and cats we would be seeing a gain of 5-6 ft lbs in the low range and a gain of 35-40whp in the upper rpm band!!
The 3.5" exhaust absolutely dominated the 2.5" exhaust that was on the car previously. This was the biggest find of the day. Since we were testing two new components at once (headers and new exhaust) we had to find a way to fit our old 2.5" exhaust that was on the car previously to really quanitfy the changes from the headers. We ended up mounting our dual exhaust upside down to make it fit with our y-pipe (don't ask how it worked, but it did!), and saw incredible torque losses with the dual exhaust compared to the single. A good x-pipe would have helped this dual exhaust, but I am still a believer that a single exhaust will always make the most power.
Whoever previously created this custom exhaust did no reasearch what so ever and the results showed it. Not only did the car sound horrible, the midrange power had losses of over 50 FT LBS OF TORQUE!!!! FIFTY!! It almost matched the top end power, lacking only a few hp, but it was the midrange where it was incredibly bad. Just wait until you see the dyno tommorow, it just goes to show how much science there really is in intake and exhaust tuning.
To be continued!
This first set is actually for a racing team, so we mocked them up on our race car and they are infact not designed to work with the factory Y-Pipes, contrary to what we are designing these for.
We got a lot of footage and tons of research done, along with testing of our new exhaust, and old exhaust. We tested the following combinations:
SGM Longtubes vs. Coast Fab Longtubes
SGM Longtubes w/ dual 2.5exh vs SGM Longtubes + SGM 3.5" Exhaust
SGM Longtubes + 3.5" Exhaust vs. Coast Longtubes + dual 2.5" Exhaust.
I will have dyno sheets along with a video and more photos at some point tommorow, I'm just updating before I go to bed, still so excited from today's events! The race car has never sounded so amazing (similar to the roadster, only a bit louder and much more lumpy and deeper - due to the Nismo cams. It also revs like a superbike because of our tilton clutch and flywheel).
Here is a breakdown:
The larger primaries and collectors in our SG headers caused a small loss of torque below 4000rpm (about 5-6ft lbs) in return for a tradeoff of about 8-10ft lbs of torque above that everywhere, raising peak power from 300whp to 312whp, and peak power gains above 15whp in the 6000rpm region. Remember, this is compared to another set of long tube headers, simply by changing the size of the pipes and collectors you will pivot the torque curve about its peak. Compared to stock exh manifold and cats we would be seeing a gain of 5-6 ft lbs in the low range and a gain of 35-40whp in the upper rpm band!!
The 3.5" exhaust absolutely dominated the 2.5" exhaust that was on the car previously. This was the biggest find of the day. Since we were testing two new components at once (headers and new exhaust) we had to find a way to fit our old 2.5" exhaust that was on the car previously to really quanitfy the changes from the headers. We ended up mounting our dual exhaust upside down to make it fit with our y-pipe (don't ask how it worked, but it did!), and saw incredible torque losses with the dual exhaust compared to the single. A good x-pipe would have helped this dual exhaust, but I am still a believer that a single exhaust will always make the most power.
Whoever previously created this custom exhaust did no reasearch what so ever and the results showed it. Not only did the car sound horrible, the midrange power had losses of over 50 FT LBS OF TORQUE!!!! FIFTY!! It almost matched the top end power, lacking only a few hp, but it was the midrange where it was incredibly bad. Just wait until you see the dyno tommorow, it just goes to show how much science there really is in intake and exhaust tuning.
To be continued!
01-06-2009, 10:37 AM
#85
Ok as promised, here are pictures, dynos and a video!
And now the Dyno's. All of these Dyno's were done on U2NDyno's Dynapack that reads a stock revup G/Z at around 215-220whp, so you know it doesn't read high!
Dyno of our Header + 3.5" Exhaust to the Coast headers and 2.5" exhaust
This dyno shows the 2.5" exhaust on both pulls, one with the coast fab headers and one with our headers. You can see that due to the larger primaries and collectors, there is more peak power but less midrange.
Finally, a plot showing how inefficient the previous exhaust was. This is both with our headers, but the lower plot the dual 2.5" h-pipe exhaust and the other our 3.5" race exhaust
These tests were done on our Koni Challenge Race car, which is entirely stock engine wise with the exception of Nismo's most mild cam (R-Tune North American cams), and a Tilton clutch and flywheel (thats why it revs and sounds so wild). Intake is Injen with a BPI flowstack but will soon be re-done to 3.5" after 13" of tube length. The engine also has a motordyne spacer, that is it! Stock heads, block, compression, intake manifold & collector etc.
And finally, the most important part, the sound!
Video:
Vimeo (High quality):
http://vimeo.com/2740185
Youtube:
http://www.youtube.com/watch?v=iU2h0JTq2fk
So much interesting data, I don't even know where to start!
And now the Dyno's. All of these Dyno's were done on U2NDyno's Dynapack that reads a stock revup G/Z at around 215-220whp, so you know it doesn't read high!
Dyno of our Header + 3.5" Exhaust to the Coast headers and 2.5" exhaust
This dyno shows the 2.5" exhaust on both pulls, one with the coast fab headers and one with our headers. You can see that due to the larger primaries and collectors, there is more peak power but less midrange.
Finally, a plot showing how inefficient the previous exhaust was. This is both with our headers, but the lower plot the dual 2.5" h-pipe exhaust and the other our 3.5" race exhaust
These tests were done on our Koni Challenge Race car, which is entirely stock engine wise with the exception of Nismo's most mild cam (R-Tune North American cams), and a Tilton clutch and flywheel (thats why it revs and sounds so wild). Intake is Injen with a BPI flowstack but will soon be re-done to 3.5" after 13" of tube length. The engine also has a motordyne spacer, that is it! Stock heads, block, compression, intake manifold & collector etc.
And finally, the most important part, the sound!
Video:
Vimeo (High quality):
http://vimeo.com/2740185
Youtube:
http://www.youtube.com/watch?v=iU2h0JTq2fk
So much interesting data, I don't even know where to start!
Last edited by SGSash; 01-06-2009 at 10:41 AM.
01-06-2009, 12:56 PM
#90
Wow that thing is no doubt loud. Love the sexy welds. You guys are gangsta, pulled the motor, put it on, just to take some pictures 
Any test going to be done on the non-revup motors? Also looking to be a little dangerous driving around the building like that with poles right next to you. Be careful. Any in-car videos to see how loud it is in car?
Any test going to be done on the non-revup motors? Also looking to be a little dangerous driving around the building like that with poles right next to you. Be careful. Any in-car videos to see how loud it is in car?
Last edited by quakerroatmeal; 01-06-2009 at 01:08 PM.
01-06-2009, 06:41 PM
#93
Well, we could consider producing a full race exhaust that would still bolt up to the headers in the factory y-pipe location, it would have all of the benefits of the system without requiring us to offer two different models of headers.
Then again, some people may want the more aggressively sized primaries and collectors, in which case we could offer that, the question is - is the price difference worth the 3-4whp more top end you are going to gain.
This is all up for discussion and I'm all ears and willing to do whatever the community wants, it may just take a little bit of time!
Then again, some people may want the more aggressively sized primaries and collectors, in which case we could offer that, the question is - is the price difference worth the 3-4whp more top end you are going to gain.
This is all up for discussion and I'm all ears and willing to do whatever the community wants, it may just take a little bit of time!
01-07-2009, 09:54 AM
#95
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wow 313 whp? that is incredible.
i would love to have a set of these longtubes but i cant imagine how it would pass smog.
you are making these headers to be able to bolt up to any aftermarket catback exhaust correct?
i would love to have a set of these longtubes but i cant imagine how it would pass smog.
you are making these headers to be able to bolt up to any aftermarket catback exhaust correct?
01-07-2009, 01:41 PM
#99
I guess the biggest point that will separate, "I;d totally rock these" to "they are how much!?" is that ballpark price range.
I'd assume ~$1500 for the headers, maybe $400 for a 3.5" with a muffler?
any ideas yet on cost?
I'd assume ~$1500 for the headers, maybe $400 for a 3.5" with a muffler?
any ideas yet on cost?
Well, we could consider producing a full race exhaust that would still bolt up to the headers in the factory y-pipe location, it would have all of the benefits of the system without requiring us to offer two different models of headers.
Then again, some people may want the more aggressively sized primaries and collectors, in which case we could offer that, the question is - is the price difference worth the 3-4whp more top end you are going to gain.
This is all up for discussion and I'm all ears and willing to do whatever the community wants, it may just take a little bit of time!
Then again, some people may want the more aggressively sized primaries and collectors, in which case we could offer that, the question is - is the price difference worth the 3-4whp more top end you are going to gain.
This is all up for discussion and I'm all ears and willing to do whatever the community wants, it may just take a little bit of time!