thehelix112

Cleve, Ignore me pls. Very excited to watch your build and I hope we see some vids like that from the inside of a zed. Well, maybe not so much the 150mph slidies. Dave

I'm not a racer's bootlace, but I think the package is more than the sum of its parts. What I'm trying to say is that you'll be a lot faster after practice/tuning than you will first time out, and I'd guess driver skill plays an equally large role in that. Dave

Very cool. Who are you getting to make the CF? Dave

So I've spent a little bit of time thinking about this, going over the JWT cam specs, reading a bit more about VCT, and flicking through the Titan FSM. As I understand it, VCT systems have the intake cam retarded at low rpm, then as rpm rises, the cam is advanced to give the air more time to start moving before the piston is actually drawing it in. This is supported by the cam specs for stock VCT and non-VCT VK56s supplied by JWT. The VCT cam as measured with VCT-off opens at 8 degrees AFTER TDC, while the non-VCT cam opens 2 degrees BEFORE TDC. Similarly VCT closes 60 deg ABDC, while non-VCT closes only 48 deg ABDC. Given the VCT engine has 2 more degrees of duration, this would seem to imply that the VCT system advances the intake cam somewhere in the region of 10 degrees as it runs. I need to pull it apart to verify this though as I've read elsewhere that VTEC for example rotates the cam 25 degrees, so 10 sounds maybe a little low. So the trick to running a large aftermarket CAM with a lot of duration and not bending valves is that the lobes need to be offset retarded by whatever amount the VCT system advances them. That way, at low rpm, the system is retarded to hopefully run a little better (though I have no idea how a large duration cam thats retarded would work, need to think about that one a little more), and at high rpm VCT advances the cam back to where it would be on a non-VCT system for maximum power. So there are a few ways to conceivably go about this: 1. Custom billet cams with the lobes offset backwards from the dowels. 2. Vernier cam sprockets allowing the cam to be rotated in relation to the dowel at will. 3. The potentially tight-arse method may involve some combination of reusing the existing cams, as each of the 4 has the lobe at a different offset from the dowel (refer to JWT VK56 installation pdf), and the FSM indicates the cam sprockets have two keyways (one for the left and one for the right banks), which based on the diagram (ha!) appear to be offset just over 90 degrees. Some combination of these might work such that the cam ends up retarded in the VCT-off position. Also need to think about this some more. Dave

Richard, Sorry I totally didn't see this update. Serves me right for not subscribing. The FSM is indeed on the to-buy list, but I don't have one yet. Let me outline what I'm thinking, from my current ignorant point. The danger with a VCT system is having it such that when the system comes on, it advances the inlet cam and opens them too much as the piston is coming to TDC between exhaust/intake strokes, causing interference. A little bit of googling suggests systems advance the cam as much as 25 degrees. So the first step will be measuring how much the VCT system advances things, hopefully this won't be too much of a hassle, though the FSM may prove far simpler The issue with piston/valve clearance towards the end of the exhaust stroke, could happily be mitigated by installing the cams such that when the system is ON (fully advanced) the maximum advance does not cause interference. It would seem that being able to install larger cams with more duration would necessitate either custom grinds offset backwards (retarded) by however many degrees the VCT advances the inlet cam, or vernier cam sprockets to customize where the cam is installed. So three questions: 1. Am I missing something/way off the mark? 2. Anyone know someone who makes such a cam? Or is it simply a billet job ($$$ that I don't have)? 3. Would it be cheaper to investigate a pair of vernier cam sprockets for this engine? Are they even possible/available for later engines, I know they are for the old L series. Thanks guys, Dave

Jake, Thanks! Planning on a Z32 5-speed if the adapters end up happening. Heard back from Nizpro in Melbourne. They think that the stock VK56DE bottom end will be perfectly happy making max power around 7000rpm, but alas, also have no experience with VCT engines. They did say though that they'd be surprised if an aftermarket profile with VCT enabled wouldn't work happily, given the systems similarity to the VQ engines, and their experiences with them. Also said that valve springs are a must for extended >6000 rpm work, so I will be ordering a set from them. I've got some thinking to do, as I am unfamiliar with DOHC engines altogether really. Dave

Jerry, I'm afraid I don't have an E31 head lying about, if you could take a photo of the combustion chamber and some basic measurements I'll be more than happy to have a crack at it. Dave

Oops.

tight little stock exhaust manifold. Reckon a set of headers should get things flowing a bit better. Hopefully gunna go with a front guard exit, though depends on clearance I won't know til it's in the car. Dave

Sold the intake. Still trying to sell the injectors, the throttle body, power steering pump and the exhaust manifolds/headers. Lemme know if you know of anyone who wants one. Just bought these: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=380248878526&ssPageName=ADME:X:RTQ:MOTORS:1123#ht_3008wt_941 (2002 hayabusa ITBs). Still looking for a second set. Starting to research how to go about getting adapter places machined up to go from the intake flange pattern to a weldable section for the TB. Then gotta find someone to machine up 8 of them. Contacted nizpro marine in my home city of Melbourne. Their vrz-60 engine I believe is based on a VK56DE, and makes 1500hp and spins to 8400. Guessing they have a little experience with these engines and might be able to advise/supply regarding camshafts. Dave

Jerry, To extend the calculator to do that would be pretty trivial given the following information: Is the combustion chamber a circle shape where it means the head gasket? And if not, what is the surface area of the shape that it is? (e.g. the Kidney shape found in P90 heads) With those two pieces of information calculating the change in combustion chamber volume for a given shaving amount will be quite easy, assuming for very small shaving values, such that the change in surface area as you progress `deeper' into the head is minimal. Perhaps in the mean time I'll add a shave field with the head value that just assumes the combustion chamber is a circle and the same size as the bore? Dave

Guys, As per topic, anyone here a distributer/guru when it comes to autronics? Lemme give some background in case anyone is: I own an Autronic SMC, I have also bought a VK56DE to convert my 1978 280Z to. I previously wired up the SMC to run the L28ET in my 240Z in Australia. I am in need of advice when it comes to running this far newer engine. I am also in need of a fresh wiring loom so I can write up my 280Z. How much is one? I've been in touch with machine-ep.com and they run around $300 for a new loom. Does anyone have any experience running a VK with an Autronic? I seem to recall the autronics being very fussy about ignition signals. For reference, this pictures shows a stock cam on the left, and a modification on the right designed to drive a VH45 computer: http://s296.photobucket.com/albums/mm178/kscherbaum/?action=view&current=VKCamsetc001.jpg I have yet to pull the inspection cover off my engine, but hopefully this will yeild a clue. Do you think its likely that the two independent signals from the two cams are simply fed into the single input to the ECU? Is the SMC going to be capable of consuming this input? I have a v1.91 SMC chipset, which is unfortunate coz apparently the v1.92 is the one that will accept a more normal 60-2 trigger wheel. Many thanks, Dave

Thats a great quote. I vote do it too. Dave

Double post.

They may be very close to drive, and I'm not arguing against the price differential, but the mustang is 6% heavier (3450 vs 3250) with 10% less power (300 vs 330), and has less rubber on the road (225/225 vs 225/245 for the base: 255/255 vs 245/275 for the ``whizz bang''). At least on paper there seems to be quite a difference. Whether its something you or I would notice around town, or even on the track is debatable, but I'd definitely notice 7K from my bank account. Take it to a track and tell us how it goes. Dave

As an aside, I'm more than happy to update that utility with any/all data you guys have. You can email it to me however you want, but the prefered method is to use the tool to add the things you have, then press the `Export' button towards the bottom, and email me the text that pops up at the very bottom. Then it'll take me 2 seconds to copy/paste it in. Regards, Dave

Cool. Did you happen to do any roll-down tests before/after to get a rough (!) measure of Cd? Dave

I also have a vk56 engine, and am very interested in these conversions. Can the flywheel be ordered to suit a smaller multiplate clutch? many thanks, dave

Took off the intake manifold so I can pull it apart to sell. Here is the engine sans manifold. And here is the sump for reference to the mods above:

Another example of DIY ITBs using Hayabusa throttle bodies. Note these have been spaced out, though I wish the pics were higher resolution so I could see how they altered the throttle linkage mechanism to work with more space between them. Maybe it'll become more obvious once I get my hands on a set. Also trying to find out the mods required to fit larger bosch injectors to the hayabusa ITBs, but again, likely will be far simpler once such things are in my hands. Urgh, forgot how expensive fuel systems are. Have also been in touch with Kurt, who was very forthcoming with the mods to the sump above. Pretty complicated for a fabrication-n00b like myself, am likely going to ask Kurt nicely to modify my sump the same way he did. Was in touch with JWT re the cams, though no definitive information about the largest cam the 2007+ engines will run. Ideally I'll be able to just take it down there and try them, but thats a bit presumptuous now isn't it? So the plan for next month is to tell the stock parts I don't need: injectors, intake manifold, TB, exhaust manifolds, power steering pump, and try to use that money to get a couple of sets of Hayabusa ITBs, and some alu plate to start mocking up the intake manifold. Apparently the stock Hayabusa velocity stacks are relatively cheap, so will investigate them more. Dave

Half the fun of travelling. Though I bet RS spoke English better than HG spoke Filipino.. Dave

OK. Well, I'll keep this thread updated with whatever I find. Dave

Hey guys, Starting to do more research on the VK56DE that I got. Read this page: http://en.wikipedia.org/wiki/Variable_Cam_Timing which talks about nissan engines adopting the ford model where oil flow is used to control the phaser. But then read this page: http://en.wikipedia.org/wiki/N-VCT which is a little more vague and just talks about it being controlled via a solenoid. Does anyone have any authoritative information? I know I should just pull the engine apart to check, but my time with the engine is limited, while my time in front of a computer is not. Plus I couldn't find any prior articles about this so figured it may contribute to the knowledge base, as I will update the thread when I do pull it down. Aside: the reason I ask this question is that I'm talking to JWT about the cams to run on the intake side. I'm thinking it'd be good to know the limits by testing various cams with manual control over the solenoid and checking for interference. I also may be totally off the track as I have that feeling that I need to think about this a little more. Obviously if its just a direct solenoid actuator it'll be easier to control manually with the engine stopped than if it needs the oil supply. Also if anyone has any thoughts on cam specs for what I'm chasing (max power low 7000), specifically for a N-VCT system, I'm all ears. Based on my buggerall experience, for a normal cam that feels like it should be around the 245 deg @ 0.05 duration, but I have even less experience (zero) with VCT engines. Many thanks, Dave

Hayabusa throttle bodies it is! Note: These aren't mine, this pic just illustrates they can be separated individually to adjust for the larger port spacing. Dave