Back to back testing of AI CNCd LS7 Cylinder Heads Vs Stock LS7.. Results Inside!!!
02-25-2011, 08:37 AM
#22
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I appreciate your info Phil, however to say it's "easy" to make 600rwhp from a stock ls7 shortblock is a tad misleading assuming a stock plastic intake, stock 11:1 compression, stock head castings, and hydraulic roller cam.
Compression has been proven time and time again the differentiating factor between the 560-570rwhp c6 z06 and the 590-610rwhp z06. That .5-.9+ jump in compression is the difference every time without fail until this. There have been a ton of claims from vendors peddling their wares, but every independent test has shown much different than their claims. In fact there have been more than a few people who've hit 590rwhp with a cam, and a $100 mill job on the heads with the ports untouched.
I hear you on unrestricting the intake and exhaust. That's why I love itb's.
You and I need to talk as one of my builds has to pass a stringent visual state inspection and I will need a plastic intake for this build at least for the time being.
Congrats again on the results. You call it easy, but I see it as a game changer. No one else is TRULY doing this with bone stock compression, and a plastic intake on stock 427 cubes.
There is a lot of smoke and mirrors out there though.
Edit: I'm not being sarcastic either. I am seriously impressed and will be in touch...
Compression has been proven time and time again the differentiating factor between the 560-570rwhp c6 z06 and the 590-610rwhp z06. That .5-.9+ jump in compression is the difference every time without fail until this. There have been a ton of claims from vendors peddling their wares, but every independent test has shown much different than their claims. In fact there have been more than a few people who've hit 590rwhp with a cam, and a $100 mill job on the heads with the ports untouched.
I hear you on unrestricting the intake and exhaust. That's why I love itb's.
You and I need to talk as one of my builds has to pass a stringent visual state inspection and I will need a plastic intake for this build at least for the time being.
Congrats again on the results. You call it easy, but I see it as a game changer. No one else is TRULY doing this with bone stock compression, and a plastic intake on stock 427 cubes.
There is a lot of smoke and mirrors out there though.
Edit: I'm not being sarcastic either. I am seriously impressed and will be in touch...
02-28-2011, 09:25 AM
#23
I appreciate your info Phil, however to say it's "easy" to make 600rwhp from a stock ls7 shortblock is a tad misleading assuming a stock plastic intake, stock 11:1 compression, stock head castings, and hydraulic roller cam.
Compression has been proven time and time again the differentiating factor between the 560-570rwhp c6 z06 and the 590-610rwhp z06. That .5-.9+ jump in compression is the difference every time without fail until this. There have been a ton of claims from vendors peddling their wares, but every independent test has shown much different than their claims. In fact there have been more than a few people who've hit 590rwhp with a cam, and a $100 mill job on the heads with the ports untouched.
I hear you on unrestricting the intake and exhaust. That's why I love itb's.
You and I need to talk as one of my builds has to pass a stringent visual state inspection and I will need a plastic intake for this build at least for the time being.
Congrats again on the results. You call it easy, but I see it as a game changer. No one else is TRULY doing this with bone stock compression, and a plastic intake on stock 427 cubes.
There is a lot of smoke and mirrors out there though.
Edit: I'm not being sarcastic either. I am seriously impressed and will be in touch...
Compression has been proven time and time again the differentiating factor between the 560-570rwhp c6 z06 and the 590-610rwhp z06. That .5-.9+ jump in compression is the difference every time without fail until this. There have been a ton of claims from vendors peddling their wares, but every independent test has shown much different than their claims. In fact there have been more than a few people who've hit 590rwhp with a cam, and a $100 mill job on the heads with the ports untouched.
I hear you on unrestricting the intake and exhaust. That's why I love itb's.
You and I need to talk as one of my builds has to pass a stringent visual state inspection and I will need a plastic intake for this build at least for the time being.
Congrats again on the results. You call it easy, but I see it as a game changer. No one else is TRULY doing this with bone stock compression, and a plastic intake on stock 427 cubes.
There is a lot of smoke and mirrors out there though.
Edit: I'm not being sarcastic either. I am seriously impressed and will be in touch...
On making 600+, 1.6hp/cid out of a 427 w/ a decent piston, a head/manifold w/ great potential, Ti valves, etc. isn't exactly setting the bar very high. IMO, YMMV.
I do not have an issue with the GM LS7 manifold. We have run them with great success, including on the ~690rwhp HR 482 LG put together that ran this same cylinder head & one of our HR grinds. The FAST LS7 LSXr was not available when we did our LS7 head program development. If we do more testing in the future, we'll be sure to include it. It may be a worthwhile alternative when we don't care to put a few hrs into the factory part.
On compression, thank you for confirming what you were getting at. I mean no offense, but it sounds like you are repeating a myth that we have heard often in regard to LS7 heads - that there is little potential from porting, and most of the potential gain is from compression. This is a good example of how flawed concepts become internet truths when we rely on anecdotal evaluation rather than scientific method. You simply cannot compare different cars on different dynos with different components and then assert that the variable you'd like to focus on is "the differentiating factor." There are so many unaccounted for variables in that type of comparison that ultimately invalidate attempts to draw accurate conclusions. It is the natural tendency for enthusiasts on forums to discount the significance of variations in methodology, setup, environment, adjustment, fluid temps & viscosity, individual tolerances in machining, and on and on. However, guys end up misleading themselves when they fall into the trap of assuming correlation = causation. For example, though the LS7 head is "CNC'd," the work is so poor and inconsistent that it alone is a large variable typically left unaccounted for. Applied to modified heads, guys mistakenly assume "ported heads" from various sources are roughly equal when they are not.
In short, we have performed empirical testing on both engine and chassis dynos, and as is invariably the case with production cylinder heads, the majority of the potential is in the passages themselves. The end user is only doing a disservice to themselves if they read forums and then attempt to impose arbitrary stipulations that mitigate the realized gain vs. potential gain of a product or modification. Asking us to ensure the engine performs safely on decent fuel is a constraint we're happy to adhere to, but attempting to stipulate specifications based on internet hearsay is contrary to the customer's best interest. So, I repeat, 600rwhp is easily attainable w/ the GM ls7 utilizing the GM head, GM intake, safely on pump fuel, HR, etc. The caveat being that it is much more difficult a goal if you're going to attempt to dictate how you'd like it to happen based on assumptions about setups that have not met that mark, hearsay, internet experts, etc.
"Wait, Doc, I know you said this was a simple procedure, but my research on WebMD leads me to believe that you should consider..."
Take Care!
-Phil
03-01-2011, 05:39 PM
#25
Great power..... how would a CnC ported TFS 235cc head/FAST 102mm setup compare to this ported LS7 head and a FAST 102mm?
I assume below 6,000rpm the TFS head would make more power and then the LS7 head would finally start to catch up and finally pull away at 6500rpm or so?
I have WCCH ported LS7 heads myself and have always thought the TFS 235's to be a better choice until 6500rpm+ or so when the LS7 heads gain the upper hand again....
I assume below 6,000rpm the TFS head would make more power and then the LS7 head would finally start to catch up and finally pull away at 6500rpm or so?
I have WCCH ported LS7 heads myself and have always thought the TFS 235's to be a better choice until 6500rpm+ or so when the LS7 heads gain the upper hand again....
03-01-2011, 09:28 PM
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It appears that the LS7 headed cars have a definite advantage over the cathedral port heads. I have a 427 (LS7 block) w/ TFS 235 heads and it's not close to 600 rwhp. I would say it's in the mid 500s. Not sure I believe 600 rwhp is normal for ported LS7 headed 427s. Are all these Z06s trapping 137+ at the strip? It shouldn't be a difficult feat.
03-01-2011, 10:47 PM
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It appears that the LS7 headed cars have a definite advantage over the cathedral port heads. I have a 427 (LS7 block) w/ TFS 235 heads and it's not close to 600 rwhp. I would say it's in the mid 500s. Not sure I believe 600 rwhp is normal for ported LS7 headed 427s. Are all these Z06s trapping 137+ at the strip? It shouldn't be a difficult feat.
http://www.youtube.com/watch?v=Db59Tqspbck
http://www.youtube.com/watch?v=LDZ160JsTnQ
http://www.youtube.com/watch?v=qevhqXO8J2A
http://www.youtube.com/watch?v=YfryDwPesbA
http://www.youtube.com/watch?v=4tJtyLI-6lI
03-02-2011, 09:09 AM
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While I certainly take no offense to anything you've said, I do have a few observations.
On making 600+, 1.6hp/cid out of a 427 w/ a decent piston, a head/manifold w/ great potential, Ti valves, etc. isn't exactly setting the bar very high. IMO, YMMV.
I do not have an issue with the GM LS7 manifold. We have run them with great success, including on the ~690rwhp HR 482 LG put together that ran this same cylinder head & one of our HR grinds. The FAST LS7 LSXr was not available when we did our LS7 head program development. If we do more testing in the future, we'll be sure to include it. It may be a worthwhile alternative when we don't care to put a few hrs into the factory part.
On compression, thank you for confirming what you were getting at. I mean no offense, but it sounds like you are repeating a myth that we have heard often in regard to LS7 heads - that there is little potential from porting, and most of the potential gain is from compression. This is a good example of how flawed concepts become internet truths when we rely on anecdotal evaluation rather than scientific method. You simply cannot compare different cars on different dynos with different components and then assert that the variable you'd like to focus on is "the differentiating factor." There are so many unaccounted for variables in that type of comparison that ultimately invalidate attempts to draw accurate conclusions. It is the natural tendency for enthusiasts on forums to discount the significance of variations in methodology, setup, environment, adjustment, fluid temps & viscosity, individual tolerances in machining, and on and on. However, guys end up misleading themselves when they fall into the trap of assuming correlation = causation. For example, though the LS7 head is "CNC'd," the work is so poor and inconsistent that it alone is a large variable typically left unaccounted for. Applied to modified heads, guys mistakenly assume "ported heads" from various sources are roughly equal when they are not.
In short, we have performed empirical testing on both engine and chassis dynos, and as is invariably the case with production cylinder heads, the majority of the potential is in the passages themselves. The end user is only doing a disservice to themselves if they read forums and then attempt to impose arbitrary stipulations that mitigate the realized gain vs. potential gain of a product or modification. Asking us to ensure the engine performs safely on decent fuel is a constraint we're happy to adhere to, but attempting to stipulate specifications based on internet hearsay is contrary to the customer's best interest. So, I repeat, 600rwhp is easily attainable w/ the GM ls7 utilizing the GM head, GM intake, safely on pump fuel, HR, etc. The caveat being that it is much more difficult a goal if you're going to attempt to dictate how you'd like it to happen based on assumptions about setups that have not met that mark, hearsay, internet experts, etc.
"Wait, Doc, I know you said this was a simple procedure, but my research on WebMD leads me to believe that you should consider..."
Take Care!
-Phil
On making 600+, 1.6hp/cid out of a 427 w/ a decent piston, a head/manifold w/ great potential, Ti valves, etc. isn't exactly setting the bar very high. IMO, YMMV.
I do not have an issue with the GM LS7 manifold. We have run them with great success, including on the ~690rwhp HR 482 LG put together that ran this same cylinder head & one of our HR grinds. The FAST LS7 LSXr was not available when we did our LS7 head program development. If we do more testing in the future, we'll be sure to include it. It may be a worthwhile alternative when we don't care to put a few hrs into the factory part.
On compression, thank you for confirming what you were getting at. I mean no offense, but it sounds like you are repeating a myth that we have heard often in regard to LS7 heads - that there is little potential from porting, and most of the potential gain is from compression. This is a good example of how flawed concepts become internet truths when we rely on anecdotal evaluation rather than scientific method. You simply cannot compare different cars on different dynos with different components and then assert that the variable you'd like to focus on is "the differentiating factor." There are so many unaccounted for variables in that type of comparison that ultimately invalidate attempts to draw accurate conclusions. It is the natural tendency for enthusiasts on forums to discount the significance of variations in methodology, setup, environment, adjustment, fluid temps & viscosity, individual tolerances in machining, and on and on. However, guys end up misleading themselves when they fall into the trap of assuming correlation = causation. For example, though the LS7 head is "CNC'd," the work is so poor and inconsistent that it alone is a large variable typically left unaccounted for. Applied to modified heads, guys mistakenly assume "ported heads" from various sources are roughly equal when they are not.
In short, we have performed empirical testing on both engine and chassis dynos, and as is invariably the case with production cylinder heads, the majority of the potential is in the passages themselves. The end user is only doing a disservice to themselves if they read forums and then attempt to impose arbitrary stipulations that mitigate the realized gain vs. potential gain of a product or modification. Asking us to ensure the engine performs safely on decent fuel is a constraint we're happy to adhere to, but attempting to stipulate specifications based on internet hearsay is contrary to the customer's best interest. So, I repeat, 600rwhp is easily attainable w/ the GM ls7 utilizing the GM head, GM intake, safely on pump fuel, HR, etc. The caveat being that it is much more difficult a goal if you're going to attempt to dictate how you'd like it to happen based on assumptions about setups that have not met that mark, hearsay, internet experts, etc.
"Wait, Doc, I know you said this was a simple procedure, but my research on WebMD leads me to believe that you should consider..."
Take Care!
-Phil
Phil, I'm glad you are not taking offense, I'm typing everything with all due respect.
I'm not interested in getting into the discussion of what compression ratio/cam combo, piston design, and chamber combo is safe for 91-93 octane in real world conditions for this thread. You, other builders, my builder, and other Ls1tech pundits are better qualified to argue what's reasonable in that regard. I always defer to my builder (HKE) for static compression. Erik likes 11.2:1 compression max for real street engines with 91-93 octance. I've begged him for more in my builds, but he refuses if I can only run 91-93. I don't feel I am missing power from his combos so I will leave it at that.
I am not repeating internet "myths" regarding stock block ls7's in Corvette c6 Z. I have not personally seen any stock block ls7 in a c6 Z with or without a FAST 102, NW102 or not reach 600rwhp with SAE correction and completely stock 11:1 compression. Not even close really. I HAVE witnessed that happening with milled heads (ported and real close to 600rwhp w/o porting) and a bump in compression.
I also haven't READ of this happening before either. Does that mean, it has never happened with a plastic intake? No. I'm not God and all knowing. I also know of more than a few people with crazy builds who choose not to post on the forums. So who knows what has or hasn't been done.
I'm not debating the merits of milling heads/bumping compression to unshroud valves, have a better entry angle into the cylinder, etc... or whether or not you can safely run 93 octane and not pull a crap load of timing in real world conditions (off the dyno).
I only seek clarification of the exact compression ratio in this test. Did you mill the heads or not? What was the before exact static compression ratio, and what was the after static compression ratio?
I'm just trying to get some parameters to put context to the test.
BTW, IIRC LG did their dyno runs on the 482 with 100 octane. In fact I do recall correctly because I was in talks with them about building an identical engine. I did not get a straight answer on the static compression ratio then, but the runs were on 100 octane.
Not an indictment on LG, as I am a huge fan of Lou and his work (as I am becoming of yours). Lou is also one of the coolest guys ever to talk to. Real car guy. I'm also not making any claims that the 482 **needed** 100 octane, but I know the runs were done with 100 octane.
You may say it's not important, or even none of my business, but as a customer who has, and is spending $40-50k on motors for his builds, I want to know exactly what I'm getting and under what conditions.
03-02-2011, 12:03 PM
#29
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This is cool...I have just acquired a complete ls7.. I have thought about putting it in my car bonestock. But 600 rwhp does hve a ring to it. The ls6 in my Camaro runs so dam good stock, if the ls7 runs as good stock it would be hard for me to want to change it. What does a bolt-on ls7 make?
03-02-2011, 02:11 PM
#30
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My only decision is WCCH or AI heads. Going to get mine CNC'd and milled .030". Friend got 20hp just from milling his .030".
Bolt on ls7 makes 490-510. With a cam 530-560. I'm making 550rwhp with a cam, intake, headers.
Bolt on ls7 makes 490-510. With a cam 530-560. I'm making 550rwhp with a cam, intake, headers.
03-02-2011, 04:39 PM
#31
It appears that the LS7 headed cars have a definite advantage over the cathedral port heads. I have a 427 (LS7 block) w/ TFS 235 heads and it's not close to 600 rwhp. I would say it's in the mid 500s. Not sure I believe 600 rwhp is normal for ported LS7 headed 427s. Are all these Z06s trapping 137+ at the strip? It shouldn't be a difficult feat.
Given the same 427 shortblock with LS7 heads and intake out of the box versus TFS 235/245 heads port matched to a Fast, the TFS heads will make more power everywhere.
A good port match on the TFS heads/Fast intake is very important and can only be performed with the intake disassembled and those parts mocked up on a block and the heads must have material removed. Anythink less than this leaves power on the table.
Sorry for the highjack, and I do like LS7 heads, it's a killer head for a production car.
Last edited by Brian Tooley Racing; 03-03-2011 at 10:53 AM.
03-03-2011, 04:43 AM
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03-05-2011, 09:33 PM
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A good port match on the TFS heads/Fast intake is very important and can only be performed with the intake disassembled and those parts mocked up on a block and the heads must have material removed. Anythink less than this leaves power on the table.
03-28-2011, 05:20 PM
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Nice gain by the way...
Jim
03-28-2011, 06:19 PM
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Congrats on just insane results with stock 11:1 compression and a stock intake. You guys need to spend more time in the c6 z06 section on the corvetteforum and post these results. No one is even close to this with 11:1 compression. Your phone call load should go off the charts very shortly once they see these results!
