996 Turbo / GT2 Turbo discussion on previous model 2000-2005 Porsche 911 Twin Turbo and 911 GT2.

Do you really need big heads/valves for nearly 1000hp?

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Old Oct 9, 2009 | 09:48 PM
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Do you really need big heads/valves for nearly 1000hp?

Nope, I just got my car dialed in at EVOMS today getting ready for the mile and we put the car back on the dyno in weather similar to that which topgun made his 805AWHP. Our cars make an interesting comparison since both are near identical builds except for the head configuration. Tom has a world class port job on stock turbo heads, stock valves and EVOMS sport intake/exhaust cams. I have a heavy port job with oversize Ferrea intake /exhaust valves and a custom ground exhaust cam with an OEM stock intake cam. Our final numbers were approximately 800/730 AWHP for me and 805/760AWHP for Tom. Clearly, if you are looking for the 950-975 crank HP range you dont need big fancy heads and valves. We had equal HP at the end of the run but Tom made more, sooner and held it longer giving him a substantial advantage. Same with TQ. I have much more headroom for future work since my power is still climbing whereas Tom is flatlining due to the small valves, but overall he has a better, cheaper package. Just for the record we were running the EXACT same file and all other hardware was identical..... Todd was kind enough to overlay Joes new numbers on our graph as well just to let Tom and I know we have real small peckers.... Joe, Tom and I will meet you at the stoplight of your choosing!!!

 
Old Oct 9, 2009 | 10:00 PM
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Interesting results and configs there... So where else can we spend out money:P
 
Old Oct 9, 2009 | 10:00 PM
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The issue is .......... you have to run a lot of boost to get there. This is where quickness and response comes into play.

In addition, the flow of the heads doesn't mean a thing without the proper displacement to match the flow of the heads. It all about proper design.
 

Last edited by cjv; Oct 9, 2009 at 10:03 PM.
Old Oct 9, 2009 | 10:02 PM
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Everything makes sense except the title (800 whp is awesome....but it is not "near 1K" hp).

My car should be making about 725 or so after my next round of mods and I would love to make 800, don't get me wrong, but I would not exaggerate the #s.
 
Old Oct 9, 2009 | 10:04 PM
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Originally Posted by Dr_jitsu
Everything makes sense except the title (800 whp is awesome....but it is not "near 1K" hp).

My car should be making about 725 or so after my next round of mods and I would love to make 800, don't get me wrong, but I would not exaggerate the #s.
well..... 800/.82= 975.6... seems close enough for comparison sakes, these are AWD cars. Now run along and sing me a song
 
Old Oct 9, 2009 | 10:09 PM
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OK....but you do know that all the other car enthusiasts, at least in my part of the world laugh at you when you are so insecure that you have to quote flywheel numbers.

On the other hand, when I say my little ol car only makes 680, and then I hang with a Supra that dynoes 800 plus, I tend to get more respect.
 
Old Oct 9, 2009 | 10:10 PM
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Originally Posted by cjv
The issue is .......... you have to run a lot of boost to get there. This is where quickness and response comes into play.

In addition, the flow of the heads doesn't mean a thing without the proper displacement to match the flow of the heads. It all about proper design.
I know...I need a 4.5 liter
 
Old Oct 9, 2009 | 10:10 PM
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Dr why do u always doubt the dyno number? Has your car always come up short on the dyno than expected? The general drive loss on AWD is 18% and 15% on RWD. So just do the math.

KPG - I will soonn find out if 1000hp required the massive heads. Although Ill have stock ported and polished heads, cams, and gt35's. Todd is estimating anywhere from low to high 900's at the wheels.

Jag
 
Old Oct 9, 2009 | 10:11 PM
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By the way, I will say that your car looks to be awesome. What I really want to see is a 60-130.
 
Old Oct 9, 2009 | 10:12 PM
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Originally Posted by Dr_jitsu
OK....but you do know that all the other car enthusiasts, at least in my part of the world laugh at you when you are so insecure that you have to quote flywheel numbers.

On the other hand, when I say my little ol car only makes 680, and then I hang with a Supra that dynoes 800 plus, I tend to get more respect.
You do know that all the car enthusiasts laugh at YOU because you LIVE in TX but havent been to the mile
run along little boy, write me a song or poem
 
Old Oct 9, 2009 | 10:12 PM
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Originally Posted by Dr_jitsu
By the way, I will say that your car looks to be awesome. What I really want to see is a 60-130.
me
 
Old Oct 9, 2009 | 10:13 PM
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Originally Posted by jags911tt
Dr why do u always doubt the dyno number? Has your car always come up short on the dyno than expected? The general drive loss on AWD is 18% and 15% on RWD. So just do the math.

KPG - I will soonn find out if 1000hp required the massive heads. Although Ill have stock ported and polished heads, cams, and gt35's. Todd is estimating anywhere from low to high 900's at the wheels.

Jag
Jags, Jitsu doesnt bother me... I quote crank numbers he talks about his bowel movements...
 
Old Oct 9, 2009 | 10:13 PM
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Originally Posted by jags911tt
Dr why do u always doubt the dyno number? Has your car always come up short on the dyno than expected? The general drive loss on AWD is 18% and 15% on RWD. So just do the math.

KPG - I will soonn find out if 1000hp required the massive heads. Although Ill have stock ported and polished heads, cams, and gt35's. Todd is estimating anywhere from low to high 900's at the wheels.

Jag
Don't doubt, just don't understand why anyone quotes flywheel numbers. Its like measuring your you know what from the bottom just so you can add an inch

Car dynoed 800...that is fantastic.
 
Old Oct 9, 2009 | 10:13 PM
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Originally Posted by KPG
I know...I need a 4.5 liter
Sorry, you can't put 4.5L in the 996tt case.
 
Old Oct 9, 2009 | 10:14 PM
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Originally Posted by Dr_jitsu
By the way, I will say that your car looks to be awesome. What I really want to see is a 60-130.
Already did one 5.5 at 3750lbs AWD on street tires...cant you read?
 


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