Dyno graph dies at 5400rpm, still 620whp *video
#1
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Dyno graph dies at 5400rpm, still 620whp *video
well just got back from the dyno, pretty dissappointing as the car would make power after 5400rpm. Kinda stumped on the issue, thinking either plug gap or valve springs. plugs are tr7's at 0.032" and springs are the ones that come with the ETP 225cc heads, bought used unsure of milage or use. Running with a TC-78 turbo and an AES 390ci.
So any one with some serious experience please chime in, thanks
-Garrett
http://www.youtube.com/watch?v=RpoPitBsZY0
http://www.hptuners.com/forum/showth...020#post263020
So any one with some serious experience please chime in, thanks
-Garrett
http://www.youtube.com/watch?v=RpoPitBsZY0
http://www.hptuners.com/forum/showth...020#post263020
#3
LS1 Tech Administrator
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+1. Your cam choice and spring choice will speak volumes here.
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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.
#4
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magnesum rockers ls1 rockers (orange in color)
springs are the double spring that came with the head
cam is an MT1 boost cam, .560 .560 224/224 144lsa.
it litterally sputters and dies at 5400.
springs are the double spring that came with the head
cam is an MT1 boost cam, .560 .560 224/224 144lsa.
it litterally sputters and dies at 5400.
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#8
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Not sure if that is your AFR on the bottom of the graph, but if it is I would regap your plugs to .026". Lean spikes in your AFR are a misfire, same issue I had and it ended being my stock ls1 coils were junk! Just a heads up too, that TC76 is going to choke out huge on that setup, way too small of a turbine wheel for those cubes. This will cause excessive back pressure and exhaust valve float. Good luck!
#9
LS1 Tech Administrator
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Sounds like Harland Sharp rockers which are HEAVY. Couple this with ETP 225 valves which are HEAVY and you most likely have too much valvetrain weight for the boost and valvesprings you're running. With just .560 lift, I'd replace the rockers with stock LS1 units and add some PRC .675" EHT dual springs. Problem solved.
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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.
#10
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Don't want to sound like a echo.
But
Really double check the springs in those heads
Some etp heads came with crane dual springs which were a 1.460 dia spring that had only 130# on the seat.
Basically spring pressure of a stock ls2 spring.
These heads work fine with stock rockers no need for roller tipped units.
A set of patriot dual springs will work fine I'm those heads
You just need the larger diameter spring bases for bronze guides.
You also would need to absolutely check the installed heights of these springs.
Also .80 wall 5/16 pushrods should not be used with these heads.
Get thicker dia pushrods.
Check out my graph with etp heads.
But
Really double check the springs in those heads
Some etp heads came with crane dual springs which were a 1.460 dia spring that had only 130# on the seat.
Basically spring pressure of a stock ls2 spring.
These heads work fine with stock rockers no need for roller tipped units.
A set of patriot dual springs will work fine I'm those heads
You just need the larger diameter spring bases for bronze guides.
You also would need to absolutely check the installed heights of these springs.
Also .80 wall 5/16 pushrods should not be used with these heads.
Get thicker dia pushrods.
Check out my graph with etp heads.
#11
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Again, another echo, Patrick is right on the mark...
Harland Sharps WILL NOT WORK. Also, ETP's heavy valves won't work with the lobes on that cam or the Harland Sharp rockers. It's going to be near impossible to make this combo work with that cam N/A not to mention throwing a few pounds of boost on the back of those large HEAVY intake valves...
I have used ETP, PI, and now MAST heads for years. I've used them in almost every configuration you could think of. Valvetrain setup on these is ultra important due to the huge changes in valve weight and valvetrain geometry. I've worked with Cary and Craig, who've designed and built those heads from the beginning, to solve these problems. You will need a MUCH more mordern and stable lobe design and springs with much more pressure and better harmonics than any Patriot or other bargain spring will provide.
If you'd like to have this issue taken care of, give me a call or shoot me a PM, I have a set of these heads on a 88mm turbo'd 6.0L in a car running 5.40's in the 1/8th mile with no valvetrain issues.
Thanks,
Shane
Harland Sharps WILL NOT WORK. Also, ETP's heavy valves won't work with the lobes on that cam or the Harland Sharp rockers. It's going to be near impossible to make this combo work with that cam N/A not to mention throwing a few pounds of boost on the back of those large HEAVY intake valves...
I have used ETP, PI, and now MAST heads for years. I've used them in almost every configuration you could think of. Valvetrain setup on these is ultra important due to the huge changes in valve weight and valvetrain geometry. I've worked with Cary and Craig, who've designed and built those heads from the beginning, to solve these problems. You will need a MUCH more mordern and stable lobe design and springs with much more pressure and better harmonics than any Patriot or other bargain spring will provide.
If you'd like to have this issue taken care of, give me a call or shoot me a PM, I have a set of these heads on a 88mm turbo'd 6.0L in a car running 5.40's in the 1/8th mile with no valvetrain issues.
Thanks,
Shane
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I will be bringing it to the track tomorrow night for the first time with the springs, slicks, more boost and the cage... if I can finish welding it in tonight. I drove it once and it felt perfect, so a log down the strip will tell the story. I will update you, thanks again Fraser!
-Garrett
-Garrett
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holy crap dude i read this tread a few days ago but dam i just noticed you have a 390 with a tc78!!!! Dude your back pressures threw the roof!! thats why it falls on its face! man with 370's at 13lbs its way to much on a tc78! let alone a 390
I cant believe no one has said this!
I cant believe no one has said this!
Last edited by BLINGOLE; 07-29-2011 at 01:10 AM.
#18
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man and with good heads and a good cam! that things probaly 50lbs of pressure in the hotside
Did you just add the note of the tc78? i read this tread before and i wouldnt of missed that i think
Did you just add the note of the tc78? i read this tread before and i wouldnt of missed that i think