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Discussion Starter · #1 ·
I finally got the flow numbers back from the GTS-R/CNC ported heads.

[image]http://www.rcgresearch.com/images/GtsrHeadFlow.jpg[/image]

This next plot shows the GTS-R heads vs. stock viper heads.

[image]http://www.rcgresearch.com/images/GtsrAndStockFlow.jpg[/image]


These are stock GTS-R/CNC ported heads and I can see they were optimized for high cam lift flow.

I should have my car back together in the next month but will have to wait for warm weather to go to the dyno. I will keep everyone posted on the results.
 

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Nice heads.

You'll want an asymetrical cam design with those heads - with more cam on the exhaust lobes.

Keep us posted - should be a great engine.

Over 300cfm is regularly achieved on fully ported stock heads, be interesting to compare ports on those. 310 to 315cfm appears the max on Gen 2 heads, not sure how thin they are at that.

Gen 3 will flow even more and can achieve 300cfm with a lot less port work than Gen 2 require.

It'll be awesome to see a certain "someone" have their own heads cast shortly with plenty of meat and fill them in with small ports so they can be strategically ported out/reshaped for best velocity/flow for application.... /images/graemlins/smiles

But as Clink said - "I know nothing!"
 

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Why do these GTS/R heads flow less than the other stock ported heads? It looks like the intake side is barely superior to the stock - what gives?
 

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Discussion Starter · #5 ·
TorqueMonster:

The heads are a work of art with all the CNC cutting and the copper seats. But I believe the ports have been CNC'd on the conservative side for the exact reason you suggested. There is a lot of material so someone can create better flow characteristics. Remember, the stock GTS-R engine only makes (I think) 525HP, but 650HP and 750HP options are available. These higher HP options use additional porting of the heads to reach these improved levels. The plots are of STOCK CNC GTS-R heads only.

See my comments below about the real value of these heads.

Clint:

Often you find that ports can be optimized for low-lift flow or high-lift flow. Since these are suppose to be race heads rather than street heads, that is where the flow is found.

Smokin:

I know! The low lift characteristics suck! These heads are definitely not the best for street use in STOCK form. I didn't post these because I believe the flow to be extremely good. I just posted them because people had asked about the stock GTS-R heads.

The real value of these heads is
1: For a high lift cam, they do flow much more than stock.
2: There is an abundant amount of material around the port areas which allows for BETTER porting.
3: Beryllium-copper seats which transfer heat much better than steel or stainless.
4: Over-sized water jackets hold more water than the stock heads for better cooling. (these heads were developed for 24-hour Le Mans racing and the extra water helps cool the heads under long endurance events.)
 

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So these heads are better for a N/A application then a turbo/supercharger? I know that flow isn't every thing....the speed of the air can make a huge differance.
 

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A couple years ago there was a lot of clammer about the GenIII heads would be THE thing to do on Gen2s, yet I haven't heard anymore about it. What happened to that 'sure thing'?
 

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Barry,

I too wonder what happened to the Heads swap like the post above. Any ideas/info?

Jay K.
 

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Tanked said:
I know that flow isn't every thing....the speed of the air can make a huge differance.
bingo....velocity is more important than overall flow numbers... :thumb:
 
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