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Discussion Starter · #1 ·
Hi, Im always trying to learn and was unable to find my the most pleasing answers that made sense to me so can some one break it down for me.

1. What is the purpose of upgrading cams?
2. Is the installation of cams, something you can add with out any support to that mod?
3. A tune is required from what I understand. But what specifically is changing about your tune? Is this where MIVEC comes into play mostly?
4. What do the different numbers mean to regular joe i.e. for the Tomei cams.
Poncam 260IN/250EX - 10.10mm(IN) / 9.50mm(EX)
Procam 270IN/270EX - 11.30MM(IN) / 10.70mm(EX)
Procam 280IN/280EX - 11.30MM(IN) / 10.70mm(EX)
Above lift measurements are valve lift, max cam lift below;


5. Why do you get the cool sound the chug chug chug sound? Does that have to do with the way the change of the lift effects the pistons or something?
6. Are cams considered part of building bottom or top half?

Thank you for your time evoxforums

warm regards
Navy:dancebanana:
 

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I'll give you a basic simplistic answer to kind of paint the picture. First don't think of cams as magical unicorn horn power adders because they are not, they are a simple support mod like a fuel pump. They don't add power they allow you to take advantage of what you have.

Think of a cam valve combo like a door (Valve is door) and air as people;


To allow more people through the door you have 2 options, bigger door or leave it open longer. So larger valves or higher lift with longer duration. Now you don't need a larger door if your only allowing 42 people in (Stock turbo 42lb/min) they are all nice and single file just walking in when the door is open. Now drop in a EF4 turbo (70lb/min) or nearly double the people and you need to make that opening wider for longer to cram them all in.

This is why some people can run 24psi and make the same power as the guy running nearly 30psi. The 24psi guy P&P'd his head added cams and 1mm over valves so he doesn't have to force it all through it just flows evenly. Thats why you just can' correlate PSI to horsepower, PSI just means there is a restriction in the line.
 

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Discussion Starter · #3 ·
Thank you that piece of the puzzle hollywood. I understand what you said. Also figuratively swapping the stock cams is like swapping the rubber IC pipes in terms of how it helps the "process" i guess....but i do get what u saying buddy

I like learning why and how things work, otherwise why waste the money.



- cams allow the unicorn juice to flow more effective
 

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keep to the topic all you other posters.
 

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Cams are a part of the head. The how-to is rather involved because you have to take off a lot to get to it all. In fact, you might as well change your chains to the new shit while you're in there. The other "while you're in there" would be the valve springs at a minimum. Valves are a little overkill, but as pointed out, every little bit helps. Oversized valves will require some hefty head work, not something you just pop right in. As you add more and more, the bill really racks up quick.

I'm leaving my cams stock for now, but when I do swap out, it won't be just cams. It will be cams and valvesprings and timing chain at a minimum. From there it'll depend on budget if I want to do valves, CNC, etc.

Valves using stock springs tend to smack into things when you over-rev... so that's one of the first things limiting you to the stock rev limiter.
 

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Discussion Starter · #6 ·
Would cams be something a average joe be able to given person has the tools.

Also thank you frank. I got some more questions but gotta digest what you said first
 

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Would cams be something a average joe be able to given person has the tools.

Also thank you frank. I got some more questions but gotta digest what you said first
If you know how to use a torque wrench, feeler gauge and can read, cams are not that hard to install. Its more of a time consuming job, thats the hard part. I believe its an 8-10 hour job with the motor in the car. Its very easy when the motor is out of the car :).
 

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I've got a question of my own...

Are aftermarket valves basically drop-in? How about retainers, are they valve-specific?

Oh and the sound you were talking about is the idle lope, sometimes stock cams will even do it. Every once in a while at a stop light my car soundz mad kam'd

Oh and hotdog sounds exactly like john83
 

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Dont do the cams yourself. Horrible idea.

People have seen gains on the stock turbo too... I think TTSumibishi gained like 50wtq with them to the point where they had to dial it back.
 

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Dont do the cams yourself. Horrible idea.

People have seen gains on the stock turbo too... I think TTSumibishi gained like 50wtq with them to the point where they had to dial it back.
Yeah, on stock turbo we peaked at 400tq but pulled it back to 370.

Navy, what are your long term definitive goals?
 
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