heads, compression, MORE power
05-07-2002, 09:14 AM
#1
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heads, compression, MORE power
Well, I had a chance today to look at the valvetrain of a VQ35DE from a 2002 Altima. My friend brought his car up to my grandfathers racing shop and we spent about 3 hours taking both heads off.
Let me tell you, if the heads on the Z are anything like the Altima's, then there will be a LOT to gain with headwork, a valve job, and MAYBE a compression increase.
Today, we finished our exhaust side polish and got halfway done porting the stock exhaust manifolds on the engine. Eventually, we will have a complete 3 angle valve job with valve seat corrections matched with custom made valve springs, a full polish job on the exhaust side, and an intake side that isn't completely polished to retain some agitation in the intake.
We ordered a custom made head gasket which should reduce head/block clearance on both sides by .015. This bump in compression should yield about .4 or .5 of a point increase, we're not sure yet how the ECU will react, but are confident of the small compression increase.
Now, to stray from the facts and venture into my personal opinions:
This car looks to have MUCHO potential. I have already learned a lot from just messing with the RESTRICTIVE as hell heads. The exhaust ports are relatively large and did not need much porting, but we did manage to bowl out the chamber to improve exhaust flow.
As for the intake side, let's just say, UGHHH! A good extrude honing will take care of the restrictiveness, maybe at a loss of some bottom end.
So, I might take some pics, I might not, depends on how much time I have and if anyone really WANTS pics. Anyway, when I get my Z, I will already have some heads up for running a N/A setup if somebody is interested.
Also, I'm sure JWT will prevail again and yield some great improvements as well.
Thoughts, comments, ridicules, name calling, flames, and obnoxiousness is welcome, hit me with your best shot, LOL!
Let me tell you, if the heads on the Z are anything like the Altima's, then there will be a LOT to gain with headwork, a valve job, and MAYBE a compression increase.
Today, we finished our exhaust side polish and got halfway done porting the stock exhaust manifolds on the engine. Eventually, we will have a complete 3 angle valve job with valve seat corrections matched with custom made valve springs, a full polish job on the exhaust side, and an intake side that isn't completely polished to retain some agitation in the intake.
We ordered a custom made head gasket which should reduce head/block clearance on both sides by .015. This bump in compression should yield about .4 or .5 of a point increase, we're not sure yet how the ECU will react, but are confident of the small compression increase.
Now, to stray from the facts and venture into my personal opinions:
This car looks to have MUCHO potential. I have already learned a lot from just messing with the RESTRICTIVE as hell heads. The exhaust ports are relatively large and did not need much porting, but we did manage to bowl out the chamber to improve exhaust flow.
As for the intake side, let's just say, UGHHH! A good extrude honing will take care of the restrictiveness, maybe at a loss of some bottom end.
So, I might take some pics, I might not, depends on how much time I have and if anyone really WANTS pics. Anyway, when I get my Z, I will already have some heads up for running a N/A setup if somebody is interested.
Also, I'm sure JWT will prevail again and yield some great improvements as well.
Thoughts, comments, ridicules, name calling, flames, and obnoxiousness is welcome, hit me with your best shot, LOL!
05-07-2002, 07:35 PM
#3
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Valves
Sounds like you guys do good work.
I thought that the valves were variable and computer controlled, what do you have to do to get around that stuff (if it is computer controlled). I've only worked on mechanical-only older cars and have been apprehensive when it comes to the newer engines because of all of the electronics.
Do you guys also do cam work?
I thought that the valves were variable and computer controlled, what do you have to do to get around that stuff (if it is computer controlled). I've only worked on mechanical-only older cars and have been apprehensive when it comes to the newer engines because of all of the electronics.
Do you guys also do cam work?
05-07-2002, 09:50 PM
#5
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Re: Valves
Originally posted by Zdude
Sounds like you guys do good work.
I thought that the valves were variable and computer controlled, what do you have to do to get around that stuff (if it is computer controlled). I've only worked on mechanical-only older cars and have been apprehensive when it comes to the newer engines because of all of the electronics.
Do you guys also do cam work?
Sounds like you guys do good work.
I thought that the valves were variable and computer controlled, what do you have to do to get around that stuff (if it is computer controlled). I've only worked on mechanical-only older cars and have been apprehensive when it comes to the newer engines because of all of the electronics.
Do you guys also do cam work?
Yes, we do cam installations, cam timing and dyno tuning.
By the way, the valves are controlled by the cams, which are variable controlled. We really don't have to mess with that, we just needed stiffer valve springs to enhance our valve job.
05-08-2002, 01:13 AM
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Originally posted by dvlad
ahahhahaha...where do you find these pic's jman?
Hope that's not a related relative
ahahhahaha...where do you find these pic's jman?
Hope that's not a related relative
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05-08-2002, 11:42 PM
#10
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Originally posted by knihc2008
actually, i'd like to see those pics.
one of the engine bay and one of the exhaust...please...?
actually, i'd like to see those pics.
one of the engine bay and one of the exhaust...please...?
I did take some pics of the exhaust side on one of the heads, though. I'll post it when I get it developed.
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