N15 GTi Track Car

Just to add to my re-build thread: http://www.almeraownersclub.com/threads/16ve-pistons-fitting-sr20de-rebuild.32609// .... some of you know i decided to add some 518 catcams with a massive 298/289 duration.

I finally got around to getting it started for the first time and bed them in. It took about 4 attempts to start, but this was in -4 temps and it hadn`t been started since mallory.
Once started it wouldn`t idle at the normal speed without stalling. I had to give it slight revs. When it was warmer it managed to idle at normal speed ,so this is good news and should be spot on with slight idle speed increase + remap with a richer richer low end.

When the weather improves i`ll take it for a spin, then change the oil.

Here`s a vid. It sounded MEAN ,this unfortunately isn`t really evident in the vid.

http://s11.photobucket.com/albums/a160/rowdy-GTi/?action=view&current=Picture222710.mp4
 
I know, i nearly hate these vids as much as i hate dyno run vids.

In person it sounded AMAZING!....... the exhaust tone was much deeper.

I cant wait for a drive and to witness 7300rpm.
 
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Reactions: Sam
GTi kurt said:
Nice one, what's the lift on these?
Click to expand...

The lift on these is in check with the size of the valve itself (unlike the JWT's which are deliberately huge so they can double up as both N/A and boost cams)
They are about spot on lift wise (.456" / .437")
which is about right in relation to the diameter of the valve and won't put unnecessary strain on the already weak valvetrain.
Joe
 
Thanks for expalining that Joe. Its 11.6mm / 11.1mm for those in the 21st century.

S3R`s are both 11.4mm.

You dont need massive lift. Once the valve is open it`s open. .....the extra duration keeps it open for longer....( as Joe once eplained to me ).
 
This is true, you dont need massive lift, the headflow on a stock DE head seems to flatline after 11mm lift. (a worked DE head is different).

However, how quickly you reach peak lift is very important.
Cams with agressive ramp profiles will always make more overall torque and have the most area under the curve. A good example of this is the JWT S5 cam vs JWT C3, they have the same duration but the C3 makes more torque everywhere.

The quicker you can open the valve, the more air can enter the cylinder. Simple.

Looking at a Headflow chart is a good way to visually see the effects of how the valvelift effects flow.

Heres a stock DE head:
http://alaniztechnologies.com/images/nissan-flow.jpg

Heres a ported DE head:
http://www.alaniztechnologies.com/images/nissan-street-master.jpg

So looking at those charts, its obvious you want the valve open as much as possible. It does matter.

...and you'll also notice the worked DE head flow on the intake side is still climbing at 0.5"/12.7mm lift too.


Good luck with the car Ian, im sure you will get good results with these cams.
You may want to raise your rev limit though or get adjustable cam gears!
 
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