Xnke

The stock 240Z airbox is a pretty nice piece. If you can make it fit (which is not a given on a LHD car) use the stock backing plate (the holes don't matter, as long as one of them is open it's all good) and stock filter element, and flip the airbox, ducting the opening into the cowl area below the windshield. If you can't make it fit, get a rusty-ish one and cut the front snorkle off, cover the hole up, and duct the back of it out the cowl. This made a BIG difference in how my car drove on hot days back when I was running SU's. I also sectioned a nice 240Z airbox (I keep kicking myself for this) and ran an open element filter right over the exhaust...bad plan. Car ran like crap on 80* and hotter days. There was much improvement by ducting the filter to the cowl area; although I bet you could run it through the front of the car and use a 280ZXT airbox (mounted infront of the radiator, not sure if the 280Z boxes did or not; never seen a stock one..) and duct that back to the SU airbox, of course you run the filter up in front of the core support. I bought my last 240Z (you have a 260Z airbox if it's got the square openings) airbox on ebay for 32$ shipped. If I hadn't chopped it up like a fool and ruined it, I'd ship it up to you, I still have it.

I am actually using the accessory drive belt for the MINI as my supercharger drive belt...makes it easy to remember what size to get!

I can imagine that the fel-pro will blow out the side too...but on the four that I've changed (including the one when I bought this car), all the fel-pros have failed on #6, pushing the fire ring into the big water jacket hole at the back of the head, one failed on #5 by pushing the fire ring into #6 and burning the gasket out between the two. The nissan-shaped gaskets seem to usually fail out the side under the manifolds, rather than into a water jacket. It's just a generalization, Tony, you know that. Those passages, are they from the Datsun bible? They look familiar...

Cool part is you DON'T have to take the car down! You can drive your car, and megasquirt the car, at the same time. No big deal. After the wiring harness is done, the two sensors that need to be changed are a cakewalk.

Yeah, they're that high. Look up the Dayco or Goodyear tension requirements for a 6-rib serpentine belt...Dayco does the endurance testing on their belts at 22lbs/rib. 22lbs*6 ribs = 132lbs for a normal accessory drive, for long belt life. Goodyear wants 30-32lbs of tension per rib. It's really that high.

No, I'm not finished with it. Take a read through it and you can find a few of the pitfalls I've run into.

First session of layup. 3 layers of 5.75oz cloth, in Famowood Glaze-coat tabletop epoxy. Only downside to using epoxy is that it has a 24hr cure time. But it is less brittle, a little stronger, and it was readily available. It also doesn't attack foam, doesn't stick to packing tape, and I am well practiced at mixing it. I am working on a vacuum bagging method tonight, to put down the two layers of chopmat that will get sandwiched between another two layers of glass cloth. I had some bubbles between layer 1 and 2, had to go back an fix those. (easy with epoxy, not so easy with polyester resin...)

The belt tension kills it?? Come on, that's a nothing problem. just have to design for it. Cog belts don't run such high tensions...

Looks like he made 180ft-lbs and 164hp, peak tq at about 4200, peak power at about 5600. Dyno sheet really looks like a stock cam, but there are so many unknowns it really could be the 0.490" lift cam in there. Generally speaking, a 290* duration cam will make power from 3000rpm and up...so if the afr's are far off, you could be drowning the motor right as it starts making power.

On the plug...the center conductor arcs to the ground strap. If you're gonna read plugs, gotta look at all of the plug. The outer steel ring should be pretty dark, the center porcelain should be tannish, and the ground strap should be clean and white to the bend.

I hate to bust your chops like this bud, but "it won't be costly" is not the way to do this. It *WILL* be costly. After my initial mounting of the supercharger, the "cheap build" went out the window with the ancilleries to get it up and going. I've spent nearly 670$ on this, plus almost 7 months of several-hours-a-night+ work. What are you doing for engine management? The stock ECU will NOT cut it...and you probably don't want to deal with tuning blowthrough carbs. A drawthrough carb is a NO-NO with air-to-air intercooling, one backfire and the whole front end goes up in a ball of flame. Keep in mind when making your mounts that the belt tension is around 180lbs static, PLUS the dynamic loading of a 40HP compressor! Mind the mounts and tensioner don't flex. Mine did! I have to re-build my tensioner assembly because it allows the belt to walk off the front of the slack side pulley. And that was not even under full-load! Just about 5-6 HP of drive at 7000RPM. At full loading, the belt walked off the tensioner at only 3000RPM and when I built the tensioner, I could stand on it and not get any measurable flex, and I'm 250lbs!

It's not "bench racing" as much as we've seen properly tuned 3.1 strokers make MUCH more than what you put down...so we were intending to offer solutions as to why it's down on power. Heck, a cammed stocker can make 180WHP, with proper tuning, and ITS engines make 200+ on "stock-by-rules" engines. Black, dry, gassy plugs say it's running too rich, what's the ground strap look like? White to the bend, then dark after? The stock ECU really doesn't handle cams well on stock displacement engines. If you decide to go to an aftermarket like Megasquirt or the Z31 computer+Nistune, you can probably make a nice power bump happen with not a lot of work. 45* of timing? On an 11:1 compression engine, it's astonishing that you're not getting detonation even on pump 93 AND the cam. Are you measuring with the vacuum advance connected? (which would not be terribly out of line, if you are.) Most L-series 6-cylinder engines run best with about 36 degrees of mechanical timing advance on the N42 head, with up to 45-48 degrees under cruise vacuum. The power peak seems to coincide with the stock computer; the factory engine managment goes open loop at around 4000RPM and switches to a fixed fueling map that isn't influenced by the AFM much, if at all.

That engine should be making more power than that. What are you using for engine management? That combination should be capable of a LOT more than that. What did the cylinder head flow at? A full "street port" will usually come in around 200CFM intake, 140CFM exhaust, and will be capable of at least 225 HP, if not more. Different shops call different flow numbers different things, but that's "the usual" numbers.

All that room disappears in a big hurry when you start putting stuff in the bay... Trust me on that one. The M90 and SC14 are pretty close in displacement...the M90's displacement will allow up to about 14lbs of boost on the L28 efficiently, but thermal management is *key*.

If you adjust them properly and they are in good condition, then it's a set-and-forget thing. You just don't screw with them. Check them in the spring, and in the fall, and that's it. The stock ECU isn't going to have a "race tune" and a "street tune"...it's the stock tune, all the time. You'd need an aftermarket system to do that, and as far as I can tell no one currently sells a plug-and-tune turnkey system for the L28 in the US.

Got covered in foam and bondo dust, getting closer to getting the plug made for the new hood bubble/vent for the Z.

I'd go with bent valves on 5, and mal-adjusted valves on 2. You use the Nissan-Approved Block Of Wood to wedge the timing chain tensioner; or the tool for the job, Powerbuilt makes one. Don't forget the two 10mm bolts at the front of the head, going into the timing cover, That'll ruin your whole day.

I laid out exactly how to calculate boost, and did a bit of handwaving on power projections in that thread, but the SC14 is a little more capable than *that*. It moves 1400cc/revolution...So if you drive it at a 1:1 ratio, that's 1400cc's of air displaced into the engine, when the engine itself is only displacing...1400cc's. 4-strokes only displace the full volume every TWO revolutions. So a 1:1 drive ratio will result in supernormalizing (I guess...in turbocharging it's called turbonormalizing...) and zero boost. Same thing with an M90, too...similar displacement. You need to work out what drive ratio you need to get the required amount of air into the engine. If you had, say, a 2.8L/rev Lysholm (big aftermarket unit from a cobra mustang or something) you could run a 1:1 drive and get 14lbs of boost easily. (This is an expensive, but viable idea, since you won't need intercooling at this level. It's also going to require getting creative with the packaging.)

Ugh, this is worse than bondo dust. Maybe it won't look so bad.

The SC14 is a very well documented swap for the L-series. You're looking at the wrong L-engine though, and the wrong continent, if you want information on them... Hint: Get a 280ZX aircon bracket...You'll want it when you go to mount up the SC14. Ditch that clutched pulley...it's worthless in this application...won't be able to keep from slipping when you engage it at any kind of speed. It's good for small-displacement, low-boost engines, but if you're wanting to drive it hard enough to boost the L28, you need more from it than the little clutch can handle. Also, keep in mind the SC14 uses two-lobe, straight rotors, made of thermoplastic, that do warp and the bearings are not easily replacable, and the super is not rebuildable if the rotor pack is warped. If you are dead set on the clutched-pulley idea, look for a Mercedes C230 Kompressor's M62. Small case, no snout, clutched 3.4" pulley. If you want a higher boost limit than about 10lbs, then look to the T-bird supercoupe M90. Cheap, remote-mount intercooling is trivial, has enough capacity to boost the L28 to about 330RWHP, if you can keep the thermal issues under control. The GM 3800SC unit is *ok*, but is much more difficult to package in the bay owing to the long nosedrive assembly and wide mounting pattern. If you can either machine the nosedrive, or re-machine the housing for a smaller bolt pattern, then it would be much easier to use in an intercooled application.

Sweet! Think you'll be able to snap a few photos of the engine bay and plumbing setup when you get it going? I plan to have mine at Branson Z Fest in a month, maybe one day I'll have enough funding to make it to The Big Show. The muffler is a Summit Racing cheap glasspack, heavily constructed of mild steel. I don't intend for it to last more than two years, so for 21$ it was no contest. If I get more out of it, great!

I guess you couldn't scroll down a few threads in this subforum? I have my own personal supercharging build here, and within that thread there are links and photos of at least three other builds. It is not popular, because it does require a relatively large amount of fabrication, compared to a turbo build, and you are limited by heat as to the amount of power you can extract reliably.

Last head I removed the exhaust port liner from, before re-welding the port floor and working the roof to match, went from 112cfm at 0.420" lift to 79cfm....So yes, I would call that "murdering the port flow". This was an L16 head, with a very small exhaust valve, but a similarly sized exhaust port to the L6. I like to fiddle with old datto heads....the L6 guys say don't remove the liners...the L4 guys say it has to be done...I needed to know. Now I know what *I* can do with a roundport head, but just cutting out the liners is a huge step backwards. To remove the liners, weld up the floors, reshape the port and then work it for best flow, it is a very large amount of work for a not very large increase over a well ported squareport head. If I had ready access to the flowbench I use occasionally to check things, I would have more detail than I am willing to put forth here.

How much does knife edging a crank really gain you in the overall scheme? Mine was done about half the amount that is shown in the photos here, plus a standard balance. Is the end result supposed to be lower windage loss, or lower PMOI, less torsional vibration, what?

Z24. Possibly a Z24i, depending on the ignition setup.