Exhaust Cams
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Exhaust Cams
As everyone is aware, I am building my GT 700.. my next question deals with exhaust cams. Are the EVOMS exhaust cams worth the price? my goal is 800 hp with GT28 and 7200 rpm.... sincerely all 6speeders
Robert
Robert
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I am glad someone on this forum is helping.. but are they needed?? and how much would I see for 1200 dollars ?? also what is the biggest Y pipe you can buy and from who??
Last edited by cjv; Mar 18, 2007 at 09:49 PM.
Originally Posted by PorschePhd
Not all cams are made the same folks. 
On a serious note are the aftermarket cams just reground stock cams (like they did with the 4v Cobra motors for awhile) or do they actually have a blank cam and have their own lobe design?Are there really any cams out for these motors that make them sound not so wimpy at idle
I'd like to see a pissed off UPS truck sound, kinda like a Viper.
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Sharkster
Thus far I am buy the biger Y pipe, getting a ECU upgrade, same turbos (are my tubos the GT28 71RS??) and all the internals stuff such as rods, pistons etc.... I am thinking about having the heads polished only.. what do you guys think?? I am just looking at these things and I just dont see where I am going to pick up an additional 100 horsepower.. tell me guys what am I missing????? Increase my boost to 1.7 bars?? Monday or tuesday I will buy everything so if anyone wants to bid or advise please do!!!
Thanks to everyone who is helping me
800 hp here I come
Robert
Thus far I am buy the biger Y pipe, getting a ECU upgrade, same turbos (are my tubos the GT28 71RS??) and all the internals stuff such as rods, pistons etc.... I am thinking about having the heads polished only.. what do you guys think?? I am just looking at these things and I just dont see where I am going to pick up an additional 100 horsepower.. tell me guys what am I missing????? Increase my boost to 1.7 bars?? Monday or tuesday I will buy everything so if anyone wants to bid or advise please do!!!
Thanks to everyone who is helping me
800 hp here I come
Robert
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Originally Posted by cjv
Stephen,
You are discussing one of my favorite areas. I know of no cam makers that are making the cams from billet for two reasons.
1) The metal match up with the lifters which presents a premature ware probem without making the lifters with the same material.
2) Placing the markers in the same locations.
Every cam I have seen to date with the exception of our cams have dealt only with the exhaust cams and all the ones I have seen with the exception of the FVD exhaust cam for the GT2 (with a 7200 rpm redline) has been a stock GT3 street exhaust cam or a stock GT3 exhaust cam that has a very minor regrind. But isn't regrinding without having a particular head flow pointless? Again, I know of no one who is modifying the intake cams.
Our tests have also proven that a ten hp gain is realized for every ten thousands increase in lift up to a certain lift. This applies to the intake not the exhaust. Changing only the exhaust rendered only minor gains.
In addition, recently Protomotive has taken the stock 996tt cams and welded/regrinded profiles for the intake and exhaust cams, however as with all cams that use this solution proper oil and premature wear are always a concern.
Just my opinion based on our tests and experience.
You are discussing one of my favorite areas. I know of no cam makers that are making the cams from billet for two reasons.
1) The metal match up with the lifters which presents a premature ware probem without making the lifters with the same material.
2) Placing the markers in the same locations.
Every cam I have seen to date with the exception of our cams have dealt only with the exhaust cams and all the ones I have seen with the exception of the FVD exhaust cam for the GT2 (with a 7200 rpm redline) has been a stock GT3 street exhaust cam or a stock GT3 exhaust cam that has a very minor regrind. But isn't regrinding without having a particular head flow pointless? Again, I know of no one who is modifying the intake cams.
Our tests have also proven that a ten hp gain is realized for every ten thousands increase in lift up to a certain lift. This applies to the intake not the exhaust. Changing only the exhaust rendered only minor gains.
In addition, recently Protomotive has taken the stock 996tt cams and welded/regrinded profiles for the intake and exhaust cams, however as with all cams that use this solution proper oil and premature wear are always a concern.
Just my opinion based on our tests and experience.
These cams are not based on GT3 grinds. Like you I was not aware of anyone that makes an intake and exhaust cam that works.
It takes a lot of machining to make my intake cams work. Most would not like the dollar figure it involves, so we do not do a lot of them. Then again you understand what good cams and good head work cost. It is a premium because so few know how to do it right.
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Originally Posted by cjv
The engine must be viewed a a "whole." You must identify the restriction in terms of air flow and fuel as they relate to your power goal and start there. When you change one item another item becomes the new restriction, but with each step additional power is recognized.
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Originally Posted by cjv
This is what has taken so long to assemble KA's motor. To make matters worse, when we changed the crank/rods after all the work was done we had to go back and recalculate everything.
Not sure how many members know it, but as these motors continue to increase power wise the new weak link in becoming the piston liners. The liners can be strengthened only to a point. After that you need to relieve the pressure by lenghtening the rods and shortening the piston height.
Our humble opinion is Porsche did just such a thing as the motors progressed from the 996tt, to the GT3 Street, to the GT3 Cup, to the GT3R. The rods are all different lengths. Our belief is the purpose being to relieve the pressure on the liner walls.
Not sure how many members know it, but as these motors continue to increase power wise the new weak link in becoming the piston liners. The liners can be strengthened only to a point. After that you need to relieve the pressure by lenghtening the rods and shortening the piston height.
Our humble opinion is Porsche did just such a thing as the motors progressed from the 996tt, to the GT3 Street, to the GT3 Cup, to the GT3R. The rods are all different lengths. Our belief is the purpose being to relieve the pressure on the liner walls.
Originally Posted by cjv
sharkster,
You are not recommending 800 hp on stock internals?
I concur with your can advise. 
You are not recommending 800 hp on stock internals?
I concur with your can advise. 
