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PostPosted: Mon May 16, 2005 5:34 pm 
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Joined: Fri May 06, 2005 5:52 pm
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Location: New Zealand
150bhp sounds good. Actual hp figures aside, just another 5 or 10 would do me fine. L18_B110, if its my car you wanted to see i can post some pics.

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PostPosted: Mon May 16, 2005 10:25 pm 
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L18_B110,
At no point did I state that an L20 wont make more than 92kw atw. Nor do I automatically disbelieve anyone who makes more power than me. I have some friends that make more power than me out of L20's but they are no longer 2000cc.
I just found it hard to believe that a rally motor, typically built with a wide torque band for driveability, was making this much power.
Having seen the work that has gone in to my motor to get it to it's current state of tune I also know how hard it is to make even the smallest gains from here on.

To quote rally510 "i have discovered it has the a87 head with opened up ports and a cam." and "The block has been deburred, but i think thats about all. Are the standard pistons dished? Because that is whats in it now"

Going on those specs it does not sound like a motor that makes 143hp atw. I would be glad to be proven wrong though as i love hearing about big HP Lseries.

Maybe you should get off your soapbox and look at the facts as they where presented.

Rally510,
I was not having a go at you or pick a fight with anyone, just maintaining healthy skepticism. It would be good to see some pics, and I would be very interested in seeing a dyno graph. I hope you find your extra 5 or 10hp without too much trouble.

Jake
btw you will find pics of my car from the track day at the Nats, it's no. 69


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PostPosted: Tue May 17, 2005 5:49 pm 
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Location: New Zealand
Ok I have the cam specs. I dont know what ones you want but here they are.
intake: max cam lift .33161in net valvelift .48742in 229.4' duration.
exhaust: max cam lift .33063in net valve lift .48394in 229.5' duration.
Excuse my ignorance but it doesnt mean a whole lot to me! Hopefully someone can tell me what i have here!

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PostPosted: Tue May 17, 2005 5:59 pm 
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Location: Melbourne, Vic
Doesn't by any chance say if that duration is 0.05" or advertised does it? Thats tiny if its advertised, but quite nice if its 0.05"

Dave

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PostPosted: Tue May 17, 2005 6:51 pm 
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sorry, it just says duration = 229.4 crank degrees

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PostPosted: Tue May 17, 2005 7:41 pm 
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Location: Melbourne, Vic
We'll assume its 0.05" then, couldn't see it revving past 8000 otherwise and the torque figures (and rpm) you quoted sound about right.

Dave

_________________
USA Daily: 2014 Nissan GT-R, very minor modifications for the track
USA Project: 1978 280Z, minor suspension upgrades, VK56DE conversion in progress. SOLD
AUS Race Car: 1973 240Z, L28ET, Autronic, GT35R. SOLD
AUS Project: 1972 1600, 3200km old S15 SR20DET, ground up rebuild. SOLD


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PostPosted: Tue May 17, 2005 7:52 pm 
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Heres the ignorance thing again! So what does that mean?
The cam place said there is room to move on it which will increase power but at the expense of low end torque. He said increase the inlet by 6' and the exhaust by 16'. what would this do?

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PostPosted: Fri May 20, 2005 2:40 am 
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Location: Melbourne, Vic
What does what mean? If you increase the duration you are altering the characteristics of the engines ability to breathe at differen rpm (vacuum/air velocities).

A cam with longer duration will typically have longer valve overlap which I believe means:

1- at lower rpm the actual TIME both valves are open is longer and more charge is lost out the exhaust valve. Even though at lower rpm the air velocity will be less than at higher rpm I'm assuming the longer time the valves are open more than compensates?
2- at higher rpm the air velocity is greater, but the flow is limited by the time the valves are open, hence the longer the valve is open the more air can get in and the air will have less of a chance to flow out the exhaust valve during valve overlap (given this occurs at the very beginning of the intake valve opening).

Does anyone know if air velocity increases more slowly than the time required to fill the valves at higher rpm?

Dave

_________________
USA Daily: 2014 Nissan GT-R, very minor modifications for the track
USA Project: 1978 280Z, minor suspension upgrades, VK56DE conversion in progress. SOLD
AUS Race Car: 1973 240Z, L28ET, Autronic, GT35R. SOLD
AUS Project: 1972 1600, 3200km old S15 SR20DET, ground up rebuild. SOLD


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