ozconnection

Round port head to round port header= good. Round port head to square port header= good. Square port head to square port header= good. Square port head to round port header= not so good, but maybe saying its 'bad' is not entirely correct either. From my experiences, this is how it is! Cheers.

There are several "stock" cam profiles, all with slightly different lifts and durations, but they're all essentially 'about' the same size. Having said that though, the one you have in your L28 is what I have in my car, 240 degrees intake and 248 degrees exhaust duration. This is a good cam for torque. Adjust it by advancing it to gain even more low rpm throttle response. But to get a stock cam to be able to rev (and have good power) to 6K is to build a different animal and will usually require a larger cam. You can't escape the fact that you have a heavy vehicle. You also can't escape the fact that for such a vehicle, the engine is small even if its a 3.1. So decide what you want from it. Maybe one of those BMW engines for a nice 'high tech' approach. Or a P40 OHV 6 cylinder engine or even a late model TB48 Nissan engine. Something to consider mate. You have moved away from the idea of building a turbo L series engine. A low boosted version with a reasonable high static compression ratio of 8.5 would see great low rpm response and a moderately powerful top end. You keep asking Tony D about the cam. I think you should know the answer to that one by now.....gee, he's written it down here and in other threads similar to this many times. So have others on this forum. Time to move forward. Best of luck with your project, whichever way you go! Cheers.

Yes Tony, tell him about slipping a tooth on the cam sprocket like you did for those guys in Japan........ I did that by accident once on my dad's C110 L24........absolutely transformed it. Oh, and I can send you an MQ, an E32, a P65, Y70.............if you like?

Called an MQ Patrol in Oz. Nearly bought one myself a few years ago.....had an L28 too! A stock cam will give the most low rpm torque. With a higher compression ratio that you will have with your stroker, watch out for pinging with a stock camshaft profile. Backing off the timing because of pinging is definately the wrong solution. At lower rpm's, its a balancing act with cam, compression, fuel (Octane) and ignition timing. As mentioned, stock EFI won't work with this combination. At this point a mild grind cam must be used to make it all come together properly. Just remember, your cam is your engines brain...get this wrong (over enthusiasm) and you're going to be driving a 'pig'........you need to keep low rpm torque man and that means a conservative profile. I've had good success with turbo grinds....they have minimal valve overlap. Check them out! Cheers.

I had to give the link for this one!!! http://forums.hybridz.org/showthread.php?t=143259&highlight=small+port+heads Read this....it's applicable to you. Carbs may not be as good as EFI because of the angles/slopes you might use your machine on. There are some Holley's that are off road compatible but if you already have a megasquirt.......then use that!! Cheers.

No. Could be an N47 head, sometimes the 7 can look like a 9. Post a pic. Cheers.

Firstly, welcome! I've never seen anything like this before. I have seen a single groove or back cut on valves before however it was said to be not worth the effort. I dunno about this one. I really don't see how flow would be encouraged into the cylinder as the valve curtain area has some of the highest gas velocities in the engine and those 'rings' don't look to me like they'll encourage 'flow' much. An increase in surface area they have but will this aid the engines performance? Some sort of flow testing needs to be performed on those valves. Then an engine dyno is needed to establish power improvements and then chassis assessment to PROVE economy benefits. Is it worth it? Spend the money and let us know how you get on.

Jeez, I just thought, "I don't have one of those manifolds yet, should get one to add to my collection" hey Pete:icon45: Don't worry mate, if I find one on I.M., it's yours!! As for the LD manifold, that'll look cool under the bonnet of an MQ, go for it boys!! Cheers.

I dunno what the end result will be exactly as I don't have it in my hands yet (you guys figured that I bought it!!) but I expect that someone would have checked this out before the cast was made. I hope!

Thanks for the info Tony! Yeah, just an observation about the stock US spec 280zx turbo exhaust manifold. Like I said, I threw it at this guy here in Sydney who could flow test it for me in view to getting it extrude honed. Now I'm not doubting the horsepower potential of that manifold at all. Crikey, some guys are getting impressive power figures out of them.....stock. We all know this. But if the flow figures were tweeked via porting, at least so they all flow about the same, then there might be some improvement in power, yes? (Well that's how I used to think about it!) But on the contrary, it seems your observations and comments indicate that all this effort on the exhaust side before the turbo may be a waste of time. Hell, if the F1 guys don't need to bother so much about it because of negligible power differences, why should us street performance guys make a fuss? I like this thinking better Tony, cheaper too! . Just bang it on and run it!! The position of the turbine outlet and housing is something I have to consider. The position of the chassis rails on the P230 series is a problem with any turbo that uses a larger than 0.48 turbine housing and the stock US spec turbo manifold. Even with that on there, there's buggar all room! I'm at least hoping that this manifold configuration will clear the rails. And if the exit pipe runs straight out of the turbine, WoooHooo! And if it has an external gate option....fine. And if it flows...hell who cares how it flows, doesn't seem to be terribly important it seems.....double fine. Maybe some sandblasting to freshen it up and apply one of those HT Coatings to keep the heat in and 'Bob's your uncle!?' That's a T4 sized flange too, yes? Thoughts? Cheers.

Thanks for the input guys. This setup would be a compromise situation for those people who couldn't find/afford the genuine factory turbo manifold way back then methinks. The sweeping manifold design is late model zx (ego sensor boss plugged with a pipe plug) and their internal passageways are reasonably generous, so that's a good starting point. I've had the factory turbo manifold on a flow bench prior to exploring the idea of having it extrude honed. Some ports flowed OK, others were well behind. It would be interesting to flow the zx manifold to see how it compares to the stock turbo one. Anyone done that??? My 'gut' tells me it would be pretty good but nothing tells the whole story better than a flow bench!! That 180 degree bend is probably a flow killer but then, maybe it's not too bad? Dunno! Who made these things? Anyone seen or used/uses one like this? Cheers everyone!

Do these turbo adapters for the stock exhaust manifold work? Does anyone have one? It seems to be cast and have a wastegate provision. Who made them, does anyone know? Thanks for your input. Cheers.

I think there is some support for your ideas of a triple piped exhaust system, from the aspect of low gas restriction. None of us can talk from experience here (I don't think?), as I know no-one who's actually built one for an L Series. You could be the first!! From what I've read and understand on the topic, camshaft timing plays an important role. Lets not discount firing order, induction setups, and cylinder volumes as other important components in the 'overall' picture but if there was a point to start with, it seems this one is a good one. We all know the firing order is 153624, the crankshaft determines this and each firing event occurs 120 degrees apart. This number is significant. When we look at very stock cams, their seat to seat duration can be as small as 240 degrees. Coincidence? No! (On the induction side of things, look at the twin carb setup.....this is also significant!) The pressure waves that pass through the exhaust system can be used to scavenge an adjacent cylinder of exhaust gasses and even draw air/fuel into the cylinder during the valve overlap period, if setup correctly. Now, realising this, the connection of pipes should be so that there is an exhaust valve opening connected to one that's just closing. So, that means that cylinders 1,2, and 3 are connected together and 4,5 and 6 are connected together in the other group. This will satisfy the above requirement of even, 240 degree (alternate bank) pulsing in the two separated exhaust systems. The fact that everyone uses a bigger cam than a 240 degree cam may be a good or bad thing, dunno exactly. I can only assume that a longer duration 'may' help, giving more time for the above mentioned scavenging events to take place during valve overlap. So, a triple exhaust may work along similar lines, but you'll have to try this one and let us know how you get on with it. Posting a couple of dyno sheets with back to back run would be invaluable, noting in particular any changes to the AFR's as this will effect the engines' performance significantly and alter the resultant torque curves, potentially leading to false impressions if not corrected for. The order of pipe connection with the triple exhaust will be the 'acid' test. And the lengths and diameter of the pipes will offer a degree of tuning, for sure. Dunno if this helps any, just thought I'd throw it in there. Cheers.

Here I am!! Well done on your successes PK!! I will talk with you soon about all that 'stuff'. Cheers. That P65 throttle body is what was described earlier, I did throw on a mike and it measured approx. 32mm primary, 34mm secondary. Everything could be slabbed though, the thickness of the throttle blades and the shaft, screws et al are far from streamlined. CFM increases wouldn't be hard at all with some time and effort. Also, on full throttle, there could be at least 5 degrees more opening available on the secondary side. (The linkages fall short from opening it 100% unfortunately.) Work here could get some more throttle and thus more cfm. Worth it? Depends on what you want really but Tony D was right. Great to rest your foot on the throttle just before the secondaries open, knowing exactly where you are, primed and ready for that extra something when you push the throttle further to the floor. Great vacuum in the manifold for econ. when cruising around on the primary only. I like that. Cheers!

Were the cam journals and cam towers lubricated before you tried this test?

It's not that bad......I ran a 4.86 ratio in the diff with my 5 speed at one time. You certainly don't have to slip the clutch at all with this sort of gearing...it will save your clutch in the long run. As far as 'off the line' response is concerned, I hope you can change gears quickly . I know my car is a street driven vehicle, but geez I had some fun with some much quicker cars! They'd pass me later on after I gave it a bit, them shaking their head going WTF! . Its addictive man. Cheers!!

Contrar! I like what you've got there! Multiply the final drive by your 5th gear ratio and it comes to 3.18. In a small car like the Z, you'd have good response and economy. The other ratios are good too! It'll be quick off the line IMO. My stock Datsun 280C ran an auto with 4.11's final drive. Then I put in a 5 speed with a 0.86 o/d and that was a revelation. It worked out to 3.53. The next 'box I put in had a 0.75 o/d and that lost me quite a bit of acceleration in 5th but my car weighs in @ 3200 lbs! (Overall 3.08 ratio) You won't have any problem with your car. I say get it. The price is right as well! Cheers.

I just received my P65 intake. Tony, you mention that one is for the L20 and the other is for the L28...are they both called P65? What other differences do they have? You mentioned throttle body, mine has the twin throttle plate setup and both are about the same size. The runners to the head are 28mm's. Do you think this is a 2.0 or 2.8 version? Anyone can chime in if they like. Cheers.

Great stuff! Love the old skool look with the Holley etc. Just curious, what made you decide to use a 4 barrel Holley? I wish you luck with one of those. I say that because I have enough trouble tuning one on a N/A engine. What kind of ignition? Do you have some kind of boost retard? Anyway, looks great!! Well done mate. Cheers.

Hmmmm, one of the duties that I have for my Datsun is towing. Yesterday, I hitched up the trailer and drove up the freeway with the Klinkman to pick up a cheap L24E I bought off ebay. Quite frankly, the performance of my L28 with the E32 manifold was very ordinary! No torque at low rpm's and pinging.....not all the time, but after climbing a hill and pressing the throttle a little closer to the floor would do it. Damn!! But why? Something is happening here, but do you think I can put my finger on it? Buggar! It's frustating man. I can't believe that the Nissan engineers all those years ago didn't try to build a manifold for their L20's that would work.....on L20's. When grafted onto a stock L28, I wouldn't have expected the results I'm getting. Sure, a top end monster it might not be, but I would've expected the high gas velocity through the whole manifold would have provided lots of torque. I can't feel it, maybe it's because the timing is so retarded? So many 'maybe's' and 'what if's?'. What else can I do? Cam timing? I could retard it since its fully advanced at the moment but I'm somewhat reluctant since I'm moving away from where I want my power/torque to be. I'm not saying I won't try it, but I'm guessing now....and searching for solutions in the dark. Any suggestions? I'm wondering if I have a fundamental component mismatch issue here. The solution would be to take it off and reinstal the trusty Arizona manifold. It's getting close! Cheers.

Took the car for a spin this morning and had the opportunity to put the foot down near some industrial estates. I had the water valve turned off so that coolant wasn't flowing through the manifold. Pulled the car over and opened the bonnet to see how hot the intake manifold was.....it was cool to the touch!! The runners were cool, the base of the manifold wasn't hot, luke warm is a better description. None of what I'm saying is particularly scientific ie no actual temperatures recorded, but take it from me, I was a little surprised at how cool the manifold was after a belting! And the ignition timing hasn't been altered yet, still on 7 degrees static! The power felt really good. With the water valve open, I had all sorts of problems with pinging and power reduction because of the heat factor, at least 50 degrees celcius difference if I can say that, temperature variance between ambient and coolant temperatures. It's all to do with thermal management. The water valve idea brought my attention to this idea and the advantages of a cool manifold for power, but a warm/hot one for startup and emissions etc. The automatic valve arrangement is still something that I'm looking into, especially useful in the cooler winter months. We're moving into warmer weather now, so there isn't any urgency ATM. Still, I'll keep you posted. I will try and test the car with the G Tech soon and post the results. Cheers.

Yep, what he said!

Dunno mate. I think that for this (or any) comparison to be fair with the examples of Chev's you've just given, the engine capacity should be kept the same or very close so that by altering the rod ratio, a direct comparison can be made to the power produced (by altering just ONE engine variable at a time). This idea would be familiar to all those people who develop their engines, or are very involved with fine tuning their machines. Cheers.

What????? Wrong post mate!!!