J-Spec NA build
03-31-2007, 08:28 PM
#42
thought I might jump in the convo and give some of my opinions..and observations..
-Your not going to be able to beat a Cosworth head, or a custom head by HeadGames with a stock NISMO head. For the power your trying to achieve not only will you need any head you choose ported there will also have to be a better valvejob then the one provided by NISMO..I have a set in my shop(NISMO) and can better the head by 20cfm with a valvejob alone if that gives you any idea how bad they are from Nissan.
-on the other hand, a ported NISMO head would make more power because of the chamber design..not just because of the increase in compression but the actual design
-there is no reason you need to run a Ti valve in the NISMO heads..you can run any off the shelf valve in them, along with any spring package. We prefer the Ferrea for the VQ. Ti doesn't last forever, and the weight savings you would get would not be worth the aggravation of trying to replace them if something were to happen, and the loss of reliability you would lose.
-I don't see why you could not make 300whp out of 3.5 liters when I see 1.8 liter Honda's easily making 270+
-We don't have a website just yet..
-Your not going to be able to beat a Cosworth head, or a custom head by HeadGames with a stock NISMO head. For the power your trying to achieve not only will you need any head you choose ported there will also have to be a better valvejob then the one provided by NISMO..I have a set in my shop(NISMO) and can better the head by 20cfm with a valvejob alone if that gives you any idea how bad they are from Nissan.
-on the other hand, a ported NISMO head would make more power because of the chamber design..not just because of the increase in compression but the actual design
-there is no reason you need to run a Ti valve in the NISMO heads..you can run any off the shelf valve in them, along with any spring package. We prefer the Ferrea for the VQ. Ti doesn't last forever, and the weight savings you would get would not be worth the aggravation of trying to replace them if something were to happen, and the loss of reliability you would lose.
-I don't see why you could not make 300whp out of 3.5 liters when I see 1.8 liter Honda's easily making 270+
-We don't have a website just yet..
03-31-2007, 08:50 PM
#43
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Since you seem to have a lot of insight on these heads has the excessive valve lash issue with standard aftermarket cams been fixed or do you still have to use ground nismo blanks or get shims made somehow?
04-01-2007, 04:53 AM
#44
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the NISMO heads as mentioned, are designed for the upper levels of NA use
I can't comment on someone else's experience with these heads, all I know is we've sold 4 sets so far, 2 with NISMO cams, one with Tomei and the 4th the customer was having his own cams done as a custom set - no issues whatsover with any clearances.
As to which heads will benefit from what, I don't think anyone reading this thread is qualified to answer that. That is where the knowledge and experience of a GOOD machinist becomes invaluable. These heads provde the basis of a sick build - how it turns out is ultimately up to the machinist and the tuner.
I can't comment on someone else's experience with these heads, all I know is we've sold 4 sets so far, 2 with NISMO cams, one with Tomei and the 4th the customer was having his own cams done as a custom set - no issues whatsover with any clearances.
As to which heads will benefit from what, I don't think anyone reading this thread is qualified to answer that. That is where the knowledge and experience of a GOOD machinist becomes invaluable. These heads provde the basis of a sick build - how it turns out is ultimately up to the machinist and the tuner.
04-01-2007, 05:14 AM
#45
Registered User
Originally Posted by Z1 Performance
the NISMO heads as mentioned, are designed for the upper levels of NA use
I can't comment on someone else's experience with these heads, all I know is we've sold 4 sets so far, 2 with NISMO cams, one with Tomei and the 4th the customer was having his own cams done as a custom set - no issues whatsover with any clearances.
I can't comment on someone else's experience with these heads, all I know is we've sold 4 sets so far, 2 with NISMO cams, one with Tomei and the 4th the customer was having his own cams done as a custom set - no issues whatsover with any clearances.
04-01-2007, 05:20 AM
#46
04-01-2007, 07:33 AM
#47
Originally Posted by Z1 Performance
As to which heads will benefit from what, I don't think anyone reading this thread is qualified to answer that. That is where the knowledge and experience of a GOOD machinist becomes invaluable. These heads provde the basis of a sick build - how it turns out is ultimately up to the machinist and the tuner.
I think one person reading this thread might have a clue
"Which valves did they use? And is purchasing the nismo Ti valveset absolutely necessary or do the heads come with it? I'd actually rather go SS if possible..."
As I mentioned above, you don't have to run a Ti valve, you can run a off the shelf valve, and there would be no machining necessary unless you would want to improve on the valvejob Nismo gives you.
04-01-2007, 08:13 AM
#49
I am not a forum sponsor and it would be unfair to them to post such a thing here, you may PM me, or contact MRC Motorsports as they are a dealer for us and a forum sponsor.
04-01-2007, 12:23 PM
#51
Thank you for your input Sharif, Z1 and HeadGames.
I still have more questions.
I see that the stock heads have more a flat chamber unlike the Nismo head that are concave, but are the Cosworth the same as far as in the chambers as Nismo?
What is a 5 angle raidus cut valve job, does the Nismo, and Cosworth have that done?
Someone please educate me.
Thanks
David
I still have more questions.
I see that the stock heads have more a flat chamber unlike the Nismo head that are concave, but are the Cosworth the same as far as in the chambers as Nismo?
What is a 5 angle raidus cut valve job, does the Nismo, and Cosworth have that done?
Someone please educate me.
Thanks
David
04-01-2007, 02:17 PM
#52
Originally Posted by Reyes5937
Thank you for your input Sharif, Z1 and HeadGames.
I still have more questions.
I see that the stock heads have more a flat chamber unlike the Nismo head that are concave, but are the Cosworth the same as far as in the chambers as Nismo?
What is a 5 angle raidus cut valve job, does the Nismo, and Cosworth have that done?
Someone please educate me.
Thanks
David
I still have more questions.
I see that the stock heads have more a flat chamber unlike the Nismo head that are concave, but are the Cosworth the same as far as in the chambers as Nismo?
What is a 5 angle raidus cut valve job, does the Nismo, and Cosworth have that done?
Someone please educate me.
Thanks
David
-A 5 angle cut and a radius valve job are two different things. A five angle is just that, 5 angles cut into the seat and depending on the size of the valve will determine if it fits right. There is one common angle and that is a 45degree seat which is what the valve seals to(all heads have this, and most are 2-3 angles only from the factory)..Then the machinist can use his imagination of being air and also use the flow bench to determine what angles might work on that particular head. Example would be 35,45,62,70,90
You could work the angles to make somewhat of a radius but that won't work on the VQ intake side. And a radious can be just 3 angles, the third being the radius end of the valvejob.. valvejobs are the most criticle factor in headporting..it can make you or break you and is one of the most highly guarded secrets.(NISMO has only 3angles, and there a ****ty 3 at that..Ray Charles must have been on that design team)
An example of a 5 angle intake valvejob, you can see the angles cleanly because there different colors as the light hits them.
And a exhaust radius valvejob...sorry for the grinding marks.. it wasn't blended in yet!
04-01-2007, 06:05 PM
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W00t i finally just maybe maybe maybe started a useful thread! YES!!! lol i feel like a father...so full of excitement from what i have created lol.
On a side note, Headgames, i sent you a PM regarding some headwork, just checking wether you got it or not.
On a side note, Headgames, i sent you a PM regarding some headwork, just checking wether you got it or not.
04-02-2007, 04:24 AM
#56
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Originally Posted by HeadGames
I think one person reading this thread might have a clue
"Which valves did they use? And is purchasing the nismo Ti valveset absolutely necessary or do the heads come with it? I'd actually rather go SS if possible..."
As I mentioned above, you don't have to run a Ti valve, you can run a off the shelf valve, and there would be no machining necessary unless you would want to improve on the valvejob Nismo gives you.
"Which valves did they use? And is purchasing the nismo Ti valveset absolutely necessary or do the heads come with it? I'd actually rather go SS if possible..."
As I mentioned above, you don't have to run a Ti valve, you can run a off the shelf valve, and there would be no machining necessary unless you would want to improve on the valvejob Nismo gives you.
I was waiting for you to post here...figured you would find it
04-02-2007, 06:55 AM
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I have been researching to try understand what all components/aspects of my stock motor would need to be addressed to have someone do a NA build. I thought I read in another thread that Cosworth starts with NISMO Spec 1 or Spec 2 heads and performs their "magic" from there. Can anyone speak to that?
04-02-2007, 07:05 AM
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scratch137 if you don't mind me asking in your thread since we have some knowledgeable contributors, how do stroker kits factor in? Z350Lover (Richie) has done his NA rebuild and his motor can live all day at 8 grand and I've seen in-car video of him doing a throttle blip and burying the needle past 8 grand on his NISMO cluster. Are stroker kits to increase displacement high revers or do they make their power at lower RPMs (stock redline)? Can an 07 dual TB and intake be installed on earlier motors like my 03?
Last edited by Sk8fe; 04-03-2007 at 02:59 AM.