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That's a cool article and short of performing the same sort experiments they did with the Chev heads etc, I would be happy to suggest the same trends apply to the L6's. There's no doubt in my mind that the little Y70 head had done good things to my torque band at lower (less than, say, 4k) rpms compared to the L28 N42/N42 combo it replaced and I subsequently raced against in my friends 330 Cedric (manual shift) Wagon. The concept or idea that you can tune your engine with port size is therefore something not to be overlooked or forgotten about when building a street motor. The article even goes so far to claim that 'too big a port size' will drop power (even when top end power is a priority as in race spec). I've always known that once a port was too big, the only option was to remove the head. Most people just wouldn't do that though. They've spent the money and were assured that the big ports were needed to get to the level of performance they were after. With a small port head, you can be confident that you'll get the best low rpm torque possible and that with a suitably spec'ed camshaft, you'll still keep a decent top end. Considering that on the street, most of your driving is with the engine turning at rpm's less than 4k, response in this range is paramount. Full throttle, max rpm 'stabs' are few on a daily driver. It makes no sense to be fixated on this. Too bad the article didn't explore using different cams but that would've been a truely mammoth undertaking. I'd sure as hell be interested in those results because the small port theory that I was pondering has already been confirmed by others. However, designing camshafts to take advantage of the smaller ports higher velocity would be a very interesting project indeed. The search for 'that' cam continues... Cheers

That's fantastic Peter! Based on what I've seen of your work with L's, you're the man! I'll talk to you soon and we can discuss my options. Cheers!

What does that flywheel in post 28 belong to Peter. I note it has eight flywheel bolt holes.

I wouldn't have thought a turbo grind would work either...initially. I'm open to suggestions however. I will pm you Xnke and a call to Isky would be brilliant. If I'm going to this effort, I may as well have explored all my camshaft options. Thank you again for your help and assistance. Ideally, my head should be 'shipped' over so that a custom grind could be researched and developed...who has that sort of time and money? Donations are most welcome lol

I'm surprised I never bothered to look at the Schneider camshaft web site before. I couldn't believe how many turbo grind camshafts they have listed there. I quickly found the one I have in my white car and realised how mild it is compared to some of the others. I want to explore this 'unconventional' pathway by getting a bigger grind and using another Y70 head on my other cars rebuilt and modified L28 bottom end (the coupe). I have a spare Y70 head so that's easy. I have most everything to do it except the camshaft. I was thinking of using the 292-84-14 grind. A turbo grind. Two steps larger than what I already have in the white car. The coupe currently runs a P90 head with 1mm oversize intake and exhaust Ferrea valves. An "A" grind stock cam. Nothing special at all and the quarter mile times aren't any better than my old N42/42 combo. Both had 8.3 compression. The coupe ran a 16.7/131kmh quarter. The Y70 on a 1.5mm over L28 with VG30DETT 4.5cc dish 'flat tops' will see a high compression ratio of over 11 to one! Maybe some unshrouding and chamber work could bring this down to 10.5. The white cars L26 runs 10 to one and has zero ping!! That's also with dished pistons! These little chambers are very ping resistant. I've been encouraged to try this because of the success I've had with the setup in the white car. All I think I need in the coupe is a bigger cam for more top end with the Y70. I like a turbo cam because of the mininal valve overlap, docile idle and good manifold vacuum it gives. Important features when running in a heavy car like mine. I'd better hurry up. Parity with the US dollar is falling. Not good. Postage is the killer but. Hmmm.

Do they enhance the performance of an L Series motor?

Nope, they've tried there already, that's why they're here.

Ok, here is some news on that little Y70 head. The old L28 (N42/42) in my Cedric pulled a 17.7 second/128km/h quarter mile last year. Last night at the dragstrip here in Western Sydney, the new L26 in my Cedric pulled a 17.1 second/133km/h quarter mile! What I'm thinking is that the small port head, compression ratio and camshaft made up the difference. (I'll ignore the slight variance in engine capacity) I raced against my mate Dave who has my old N42/N42 in his car now, totally unchanged from when I had it and totally stock, cam/compression/ports etc. Cam is on position one (as it was in my car). He runs a 4 speed manual and dual round top SU's. Last night he pulled a best of 16.9 second/130km/h quarter mile. (my time was 17.7sec/128km/h with the same engine remember?) So what makes his car quicker than mine with the N42/N42? Manual trans? Dual carbs? (He was chirping second AND third gears) And what about the improvement given by the L26 in my car? Especially the times. Not massive I know, but significant in this realm anyway.

Yep, fantastic layout. Totally had a ball on the track, a nice combination of straight bits and curves. My 240C coupe ran well but nowhere near that little zed. He has a lot more power and a lot less weight but its safe to say we both had buckets of fun out there!

Doesn't sound like you have a problem at all. Drive it and enjoy your creation man! Cheers.

Try putting those Allen bolts in with the fan in situ....

Drag engines are refreshed regularly. Those little holes would fill with carbon very quickly and on a street car would be useless in no time.

I tried the CSR pump.....don't waste your money on it. Stick with the stock OEM water pump, be happy with your decision and don't give it a second thought.

That thing is a Jap. factory spec. water/oil cooler for an L20A ET. I'll be down at PI for the nationals in Easter, come and see for yourself.

A new combination for my 240C coupe, Megasquirt EFI and 1000cfm throttle body.

I did notice that the little red LED sometimes does strange things too, not the usual style of blinking that I see normally with warm up or error notification. I might buy another LC-1 and oxy sensor, and try that first. The LC-1 was a second hand unit I bought with the Megasquirt EFI setup I have and I think that the new o2 sensor in the exhaust isn't genuine. The cable is different slightly in its construction but the part number on the plastic bag was correct. (as if thats convincing) We'll see what happens. PS I've gone off topic with this thread. Sorry mate, I apologise for that.

I've done a lot of reading from the sites and I still see some big grey areas. The trouble is you dont know whats important and what isn't. You could read a sentence that could make a HUGE difference to the tune overall, but skip it because its included with other stuff that looks fairly irrelevant. Injector dead time for instance....wtf is that?? Maybe I should have bolted all this stuff onto an old cluncker. I really don't want to wreck my lovely new engine whilst hit/miss with this new efi stuff. I had a map sample error and found buggar all information as to what it was or how to fix it. Now, it seems to have gone. My o2 reading on tunerstudio is still reading stupid reading, one second its 9 to one, then 22 to 1, and its sending autotune into circles....the engine runs like crap as you can imagine. I will plug the innovate into the laptop, maybe there is a silly setting there thats causing this to happen. OR, I'll buy another LC1 and try that. Error code 9 is gone now with my mods but the thing is still silly as mentioned above. The o2 sensor is brand new and properly calibrated.

I've had this happen to me on one of my N42's. Stock cam, retainers and lash pads. My solution was to grind the contact face on the rocker arm where it rides on the lash pad. You don't need to take off huge amounts, grind it parallel to the long axis of the rocker arm and then polish the surface when you're done. You will need to check that there is no contact between the underside of the rocker and the edge of the retainer after this mod. If it does touch, youll need to notch the rocker arm where it touches. Polish the scar after you've made it or it will become a stress riser. If you get it wrong, grab a spare rocker arm and start over. I got it right the first time, a grind, then check geometry, another grind, check again etc etc etc. till I had the right wipe pattern and correct lash with the same pad as all the other valves. Absolutely no issues whatesoever with this modification. PS, Heaps easier than cutting the valve. That's a big job compared to my simple fix.

I drove it around the block the other day. Response is good and power is adequate I still have to learn how to tune with Megasquirt. It's only a matter of time.

Megasquirt 2 version 3 motherboad. Tunerstudio software has an auto tune feature. It's sick az! I've had some issues getting the innovate WB proper and stable voltage. Now I think I have that sorted, it's tune time.

Ok, will do. I will take this thing to the dyno once I'm happy with the tune. Then, after the other stuff is put on, I'll take it back to the same dyno to see what difference there is. So much to look forward to in 2013!

Yep, all my friends are saying the same thing. I do like the auto tune feature in Tuner Studio. It's so cooool!

The advantages of converting to efi though, are that you dont have to play 'by the rules' . The advantage now, as I see it, is the removal of the restrictions required to make a carb, by it's very nature, work. Top end power will increase IF there was some reduction to the intake flow potential caused by the carb. Maximum flow potential through the manifold can be realised. I chose this route (4 bbl efi) because I had worked on carbs for way too long and even though I landed on what I believe to be a 'well setup carburetoer' for my application, I wanted to experience the difference EFI would make. The longer term option will be to run a blow thru turbocharger through the TB for that added little something! The large variety of 4 barrel carb manifolds for the L series sixes are more than what was on offer for EFI and even though the stock efi manifold supports some excellent, well developed and powerful engines, I just don't like them. That's not a rational comment I know, but so is asking someone their favourite colour or who is the sexiest woman in the world or.... For me, the variations in the carb. manifolds design will alter the running/operational characteristics of the engine so much, you could 'tailor' or tune your engine in much the same way you do with head and cam specs. Yes, I concede that there will be some inherent design flaws using these manifolds BUT I think you're only going to find them as 'limiting factors' at much higher states of tune. For the street and even for some track work, they're fine. I testify to these statements based on my own experiences with these manifold/carb arrangements for the last 25 or so years. I would love to design a manifold specifically for the throttle body and injector arrangement. You don't have to worry about things like fuel bowls so the whole TB could be turned 90 degrees so air entry could be side draught. Six tubes (equal length or otherwise) could snake and merge as do header pipes do, to a plenum under the TB. Just an idea. The twin su manifold 'seems' to be a reasonable piece of kit, how do you account for flow variations you're aware of? I would have thought the engineers at Nissan would have been fairly close to spot on, working on stock engines (stock cam timing re induction pulses/reversion etc)?

Yep...and not even a call you're not comin over.

Sweet ride it is!!! I love it. Thanks man. Yep, it's a factory L20A ET spec water/oil cooler.