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Twin cam head for the L6 from Derek at Datsunworks


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This is all Tony D’s fault:)   Hi everyone. Some of you know me from my  DIY EFI manifold project http://forums.hybridz.org/topic/63445-making-my-own-efi-intake-the-first-casting/ &#

Machine work finished!   I can relax a little:) Just got done with their first bath. Still need de-buring and edge finishing but the majority of the work is done.    

Yes, the exhaust port 'could' use some work, the as-cast cleaned intake is flowing within 10cfm of a 4 hour port job on an OS Giken head.   Those numbers outflow most max ported SOHC heads

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Get it on a dyno and I bet your eyes go wide.

 

It probably is making GOOD power throughout the band-it's just that the cams, header, and intake all come into sync starting at about 5000RPM and all pull together to about 7800RPM.

 

Tried to tell ya early on about big cams, ITBs, and tuned length headers, but now you got the first-hand grins. My Apologies for the addiction, it never gets better. I bet every time you get in the driver's seat and turn the key you just have to give it a 5000RPM flick just because you can.

 

Now, when you get a chance to put together a higher compression stroker (say, 10.5:1 with the current cams and that compact chamber) of 3.0L or so...You'll be rolling into the throttle in 2nd rather than shift up just for the sound and the big pull!

 

How is the tuning going? Any tough spots that don't seem to want to smooth out or places that feel like they randomly go rich/lean?

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You're effectively running the Honda K20A2 VTEC cam profile, right? Not the low RPM profile? I would expect a huge high RPM bias.

 

And in my experience with ITBs, they rarely show gains over a single throttle intake until high RPM with big cams. They sure look and sound good though!

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Get it on a dyno and I bet your eyes go wide.

 

It probably is making GOOD power throughout the band-it's just that the cams, header, and intake all come into sync starting at about 5000RPM and all pull together to about 7800RPM.

 

Tried to tell ya early on about big cams, ITBs, and tuned length headers, but now you got the first-hand grins. My Apologies for the addiction, it never gets better. I bet every time you get in the driver's seat and turn the key you just have to give it a 5000RPM flick just because you can.

 

Now, when you get a chance to put together a higher compression stroker (say, 10.5:1 with the current cams and that compact chamber) of 3.0L or so...You'll be rolling into the throttle in 2nd rather than shift up just for the sound and the big pull!

 

How is the tuning going? Any tough spots that don't seem to want to smooth out or places that feel like they randomly go rich/lean?

 

I'm not saying it's making a ton of power. It's just makes a lot more power up high. I want to clarify that because we all know how the internet works. It's definitely  a lost faster than what I had. The tune isn't even close yet. I'm still working out a lot of little incidentals before I can really run it. But it's got quite the sound up high I will tell you:)

 

You're effectively running the Honda K20A2 VTEC cam profile, right? Not the low RPM profile? I would expect a huge high RPM bias.

 

And in my experience with ITBs, they rarely show gains over a single throttle intake until high RPM with big cams. They sure look and sound good though!

 

Yes that's correct. Since it's a Vtec killer I only have the big lobes. I knew the power band would be high I just was amazed at how pronounced it was. As I said before the tune down low may be crap and that will affect it.

 

I'm anxious to get everything stabilized so I can start tweaking the cam timing a bit. I pulled the valve cover again to put in V2 of my valve cover breather baffle and everything looked great. The valve train is a little noisy but there doesn't seem to be anything self destructing. Cam lobes look great. No grey oil from the bearing journals.

Fingers crossed:)

 

Derek

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Nice! It looks like you're moving away from "please don't blow up or self-machine" to "let's make some power!"

 

I don't have Z experience on this, but in other setups, mainly VW 16V, ITBs give only losses until high RPM, when compared to a plenum with single throttle.

 

Also, both low and high cam profiles were designed with VVT in mind, which you currently don't have.

 

For the street, a single TB, VVT, and a milder cam profile might be the hot ticket, though admittedly more boring.

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What CR are you running?  Hopefully around 12-1 with a pent roof.  I have not read this whole thread to know.

 

Put a turbo on it and join me in the 750+ HP range  :).

^^^^ Trust me Bryan, that's not the first time someone has said that first number there! LOL

 

The KA head is so much better than the RB when looking at N/A applications, the  fanboi's that are stuck on the RB just don't get that the RB26 is not meant to be N/A and it's chamber is just all wrong for N/A applications. The KA and RB25DE heads are FAR better candidates for N/A Performance.

 

The Honda guys consider 10:1 "low compression for Turbo Applications" and as Derek points out with the little quench pads and some simple piston work it's relatively easy to get to 10:1 and turbo it for some really nice useable street power.

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One other thing to remember is that he DOES have the ability to move that cam timing around on the intake lobe. A static change equal to what the VTEC adds to the cam in terms of valve events moves that power band down considerably.

 

Large cams can do interesting things  at lower rpms simply by changing valve opening event times. The Exhaust is relatively inert in this game but could be matched to the intake. A series of dyno pulls with strict discipline on changing only one thing to baseline characteristic curves would gain a lot of knowledge in setup suggestions later on...

 

I'm thinking there are at least 2,000 more rpms lower in the RPM band that may be available with a timing change experiment. No, it won't be a barn-burner up top at 9,000 rpms then but it would prove that with simple cam timing changes even mild builds would be able to benefit.

 

Slip a link on an L-Series and watch what happens to your power band. It's an interesting exercise and really eye-opening.

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Hi Everyone.

Just checking in. I've got about 120 miles on it with everything from idling at traffic lights to lugging through my neighborhood to 3 gears worth of 6200+ shifts and it's doing great. Zero problems. I've been daily driving it for the last three days and the tune isn't quite there yet but it's workable. Cold starts are a little grumbly.  No new noises in the valve train. No video yet as work has been busy and I really wanted to get the tuning closer. Speaking of tuning I've hired Jeff Linfert of Linfert Performance to help me out with the Megasquirt. Really happy with the results so far. Right now we are tuning via email and tuner studio and he has most of the major items dialed in. 

 

I'll try and get some video up soon. I have to pull the intake to add some vacuum ports and it's supposed to rain here for a few days so it will probably be Monday or Tuesday. 

 

I can't even imagine this thing on a real motor. It just keeps pulling and pulling.... At 4500 RPM it screams "Leeeeeeeeeroy Jenkins!" And then I shift around 6200. I'm such a puss:)

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I'm surprised that your still running ms honestly. Considering its a DIY ecu that sometimes tends to be a bit iffy on emi noise and bit complicated. Don't get me wrong I am running it on one of my 240 l28et swap. Soon as you mention megasquirt to a tuner and they just want to pull their hair out. I think it's great that your running it just surprised since you got lots invested in head. I am sure ms will probably put this on their list of cars running their system a great feather in Thier cap. Consider putting knock sensor if you don't have one already.

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eh, stock bottom end will handle a 7200RPM zing a few times with no ill effects...

 

Can't wait for the video!

 

The motor I bought from FHP Tom was balanced. When I pulled the pan there was a fair amount of work done to the crank. Whether it was done correctly or not I have no idea. I'm also still running the stock EDIS controller which is really the limiting factor.

I'm surprised that your still running ms honestly. Considering its a DIY ecu that sometimes tends to be a bit iffy on emi noise and bit complicated. Don't get me wrong I am running it on one of my 240 l28et swap. Soon as you mention megasquirt to a tuner and they just want to pull their hair out. I think it's great that your running it just surprised since you got lots invested in head. I am sure ms will probably put this on their list of cars running their system a great feather in Thier cap. Consider putting knock sensor if you don't have one already.

 

I've never really had any issues with noise. But then again maybe I've never demanded from it what others have. I will say that all of my sensor wiring is shielded and EVERY ground associated with megasquirt is single point. Plus not running a dizzy and using high quality plug wires makes a huge difference.  My advice to anyone who can't fully tune their own car is to find a tuner first and run what system they are comfortable with. There is a huge difference between "my car runs" and "my car is tuned"  I was able to make my car run.

 

Just remember you youngsters, you can tune a piano...but you cant tune a fish:)  Words to live by.

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Megasquirt is a solid system when it's installed properly. I'd say a solid 90% of people who have problems with their megasquirt systems can trace 90% of their problems to improper installation. (Saying that as someone who has installed quite a few of them, and fixed quite a few more for others.)

 

The tuners who scream and pull their hair out about megasquirt are doing so because they simply do not make money on them.  It takes time and effort to fix the mistakes and poor planning that many systems show up to their shops with, and they are simply not going to do free work to fix it, just so they can charge you money to tune it. A big issue with MS is that it's perceived as "cheap", even though it's not really any cheaper than any other ECU in it's capability bracket. So, people who aren't willing to pay what it takes to do a quality install, or who take every shortcut they can, are who show up to the tuner with a badly installed, malfunctioning, poorly thought out megasquirt system. Then, when it has issues and can't be tuned properly until those issues are fixed, they do not want to pay for the tuning work done OR the time, effort, and parts needed to fix it so it can be tuned. There is also no tech support like there is for Haltec, Motec, Link, etc.

 

MS-2Extra, however....Extremely sensitive to noise. The PWM-based current limiting on the low-impedance injectors REALLY can mess with the processor, and having the ignition driver (BIP373) internal to the megasquirt produces even more electrical noise. Moving both of those things out of the main board (and out of the case) makes for an extremely stable, noise-free installation.

 

Stock EDIS-6 has an RPM limit of over 11,000RPM...so that's definitely not going to be slowing up your rev-ability! I don't know what the coil pack can handle though, but my supercharged L28 runs the EDIS with a chrysler minivan coil back and will turn 7800RPM without an issue.

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There are a lot of misconceptions with MegaSquirt and Xnke nailed them on the head.  What I find happens is because MegaSquirt is such a good bang for the buck is that it draws not just the DIY crowd but the DIY cheap out, don't understand how the system works and lets put it together with duct tape and bailing wire.  Then you get a mess which either gets abandoned and sold and/or ends up at a tuning shop to get sorted.  The tuner may as well start from scratch rather than make the mess the previous owner through together work.

 

Fortunately there are lots of smart guys and girls on this forum and a lot of support so getting an MS setup up and running has a fairly good success rate.

 

Derek pointed out a couple of very important points with is MS build.  First shielded wiring for the sensors and secondly a single ground point or as its more commonly know a star ground configuration.  When we build custom harnesses for MegaSquirt and other stand alone ECUs these are critical design points we implement in our harnesses. Both of these are very important to eliminating noise BEFORE the MS unit has to take care of it.  The MS3 has very good noise filtering algorithms but its just good design to eliminate the noise before it gets to the ECU.

 

Jeff Linfert is a great guy and a wiz with the MegaSquirt - you are in good hands Darek :)  We did a build for Charles Perry's race car - Jeff did the tuning.

 

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Recall many who referenced my "problems" and I had tried to make it clear in the end it was a failing COM CHIP IN MY LAPTOP that was causing the issues. It had run and driven within 15 minutes after initial fire up, then I went away for a while and something happened to the Com Chip unbeknownst to me...and it was JeffP and I poking and Probing with an O-Scope trying to find noise sources when he probes the com signal and says "Hey man, something is funky with this chip"!.... We loaded my original tune and all was good. Hook my laptop up to it and bam, crap!

 

That can happen wth any system. In the end my MS was really just fine (and I built them myself) it was my laptop that caused all the issues!

 

With the open source and professionally assembled models out there now it's as steady as anything else in the cost range. It still is low cost.

 

People here don't want to pay shipping across the state, much less buck up for a MOTEC and $1,800 a day on a Dyno doing tuning...

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