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Twin cam head for the L6 from Derek at Datsunworks


Derek

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Ok time for a small update.

 

The head work is being done at Rebello Racing. I was interested in getting a head in his hands and everything kind of fell into place for that to happen. The only down side was they are always slammed so it's taken a little longer than I would like. They worked the bowls a bit but other than that it's basically the same as it was after the new owner smoothed it out. There was no major shape changes. Dave's opinion is the head as it is now has the capacity to produce in the 420 HP range based on the numbers they got.

 

He is onboard at this point and will be offering and recommending the head to his customers. He deals with Schneider Cams and the cores are there getting the lobe profiles done. 

 

I know it's been slow going for while. It's just amazing how long it takes to get  things like this moving.

 

I'm attaching the flow sheet he sent me. 

Thanks

Derek

 

20170707041719-6d83f753-me.jpg

Edited by Derek
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443 @ .5" lift? Isn't that about double what a ported P90 does? Did I get that right? Wow.

 

 

Did you ever get a driving video of the one in your Z? I'm dying to hear this thing at WOT.

Yea I read it wrong at first too. That row is the scale value that the flow bench is using at that lift. Then below that is the factor that you use to derive the actual flow. Dave explained it but I'm probably not describing it properly. The intake flow at .5 is 301 CFM.

 

No video yet. My video recording with the iPhone isn't sounding at all like what it sounds like in reality. I picked out a lavaliere mike on Amazon and I'm going to give it a try.

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420 with what bottom end?

 

 

Well the "right" bottom end of course:)

 

Here is how Dave put it to me. You can do it with a 3.0L but you would need to spin it 10,000 RPMs to get there. A 3.4L puts you around 7500 to hit the same mark.  He feels that a 3.2L will give you a decent amount without going to extremes.

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  • 2 weeks later...

Just uploaded a new video.

Trying out some new microphones. The placement on this video is one in the cabin and one next to the exhaust pipe. The exhaust mike is dominant at this point as you can't hear the induction noise which in my opinion is the best part:)  It's a pretty accurate depiction of what's coming out the back end though. I'll shoot one with the mikes in the engine bay next. Shifting at about 6800. On the second run I hit the limiter in first. OOps. The camera mount sucks and I need to work on it. If you look closely through the shaking you can see the front of the car lift when the cam comes on.  I drive it this way a lot. I just love the sound of it!

 

Thanks

Derek

 

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so, ok. 

 

your car, at least the exhaust, sounds godly.  just the other day, I was listening to a vid with a vintage 1950s aston martin (http://jalopnik.com/aston-martins-answer-to-ferrari-in-the-late-1950s-sound-1790551967) and your vid reminded me of that. 

 

yours is a bit more throaty but god does it sound good. what kinds of revs did you go up to, when you were really punching it?

 

let me hijack your thread for about two posts (mine and yours) and ask you what is your exhaust (I've seen your custom headers, but I forget what you're running for pipe and muffler)..

 

thanks!  and I wish my car sounded as good as yours....

 

seb

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Thanks everyone.

 

 

 

 Sounds pretty vintage actually, I think.

That is probably the best description of the sound. at least in my ears.

 

 

 

 


Magnificent sound! Sure put a smile on my face, that's got to feel pretty good after all those years of hard work, very well done.

 

 

Thanks. Yea it is a lot of fun driving. I have right around 3700 miles on it at this point. I've had a few issues but nothing related to my work. Biggest problem was a defective KA24 upper tensioner.

 

 

 

Sounds like an L !!

 

 

Thats a good thing! right:)

 

 

 

ask you what is your exhaust

 

Magnaflow round muffler as a resonator and a Magnaflow oval as the muffler. When Xnke designed the header this is the sound I was looking for. Hopefully he will chime in but it had to do with the length of the collectors.  I'm kind of pulling that out of my butt though. Not my department:)

The rev limiter is set at 7000 RPMs. The EDIS gives up at 7100 or so and that is not an elegant way to control your revs. Like really harsh when it kicks back on.  I don't know the specs of the bottom end as I bought it used from a Hybrid member who has gone dark. The crank as absolutely been balanced but beyond that I don't know. At 7000 it is still pulling like a mofo so it's not running out of cam or head.  

 

 

 

Sounds great man! You mentioned before that this was a pretty conservative build compression and cam wise, correct?

 

After I milled the head the second time I was able to get the CR to around 9:1.  Everything I have been told is the design of the combustion chamber will easily work up to 11.5:1 on pump gas. The cam is very mild and really should be considered a test item. 

 

I should be getting the head back from Rebello in a couple of weeks so development can start moving forward again. 

 

Derek

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Get someone to video you doing a drive by.

The exhaust mic is really dominant like you said . I just set my camera on a box or something in the hatch - it does a pretty good job picking up the total sound.

It almost sounds like an open header with yours. My car has the same magnafow exhaust as yours- just twice as many:)

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Boy that will make for one helluva combination with a Rebello bottom end. I haven't seen much from them lately, did they move forward with the stroker crank they were working on? Supposed to make for a 3.34 liter build if I remember right.

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