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ram75280z

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  1. That's too bad about the head gasket. If it were mine, I would build the l24. You could pretty easily make200hp using all period Datsun parts. Although a small cam, 270 or less, would be a good idea. It's easier to make more hp per liter with the l24 & l26 because all the stock intake manifolds are too restrictive for the l28 to peak at even 6000rpm. Whereas a late model 280zx FI intake can make the l24 peak at 6500rpm.
  2. Yea I remember the earlier days of the build(almost 15yrs ago if i remember correctly), posted on the internet (zcar.com). I had forgotten about his web site over the years though, which I found today. In reading it again I remember reading it before. It was the first well known, privately built, high hp l28et that I remember. It is kind of disappointing that there's not a full plot of the engine. Especially since it is so well documented & well done. Mostly I was curious about the affect of the intake on the powerband, as I'm currently working on a 34mm turbo intake for my NA l28. Honestly, I'm not extensively versed in turbo tech, but the amount of power being made with 8psi sounds like the turbo is pretty well suited. But, I do know that it's probably more suited to a 2 liter engine for high hp levels. I bet you two have had a lot of fun over the years working on it & talking about it. Hopefully you will both be able to return to all of that soon, & get to record the true capabilities of it.
  3. Hi Tony, Do you know where I could find a dyno plot of Jeffp's engine? I searched around a bit, but the posts were circa 2007ish & the photos were gone...
  4. The stock n42 intake manifold has runners of about 31.75-32mm(you can't really even say they're that size unless the casting from the injector screws is taken out), equal to 1 1/4in, so either your manifold has been ported or your measuring is a little rough. The late model, 82-83 turbo, intakes are 32.75-33mm. There's a lot of information about the intakes on this site. The simplest route to resolve this issue, if you have the money, is to purchase one from Lonewolf perfomance. I think their basic model starts at 35mm, but they will make them how you want. Or they will port the stock intake, the full length of the runner, but I don't think they have enough material in them to make the runners any bigger than 34mm.
  5. What you really need is a new intake manifold with runners that have a diameter of at least 36mm. You can change the cam & turbo, that will give you more power, but it won't extend your powerband at the top end unless you have an intake manifold with adaquate runners. A 270 cam with 36mm runners should peak right around 6500rpm on an l28.
  6. Based on the information given, amount of consumption & when you see smoke, I would say you likely have leaky valve stem seals. If it only smokes when you 'rev it up' from idle speeds, what's happening is the oil is pooling on the back side of the intake valve when idling then being sucked into the cylinder when you rev it. Rings will generally smoke consistently under all conditions with more smoke as you drive it harder.
  7. I really wasn't saying don't do it. Just saying that you're leaving a lot of power on the table if you keep the 40s on there. I only mention it because I have seen it soo many times. Many, many folks with 2.8s & stage 3 cams(and bigger) running around making around 200hp(at 5600rpm) & wondering why, because they have tripples. Yea, tripples with 32mm chokes, even some with 45s have 32mm chokes, in the name of low rpm power. They don't notice the dropoff to 4cyl power at 6500rpm, when they should be peaking around there, because their engine has that strong mid range & the dropoff is so progressive. By all means have fun this summer, & I'm sure you will because you have great throttle response & more power. But, next winter, find someone who has a 2.4 or 2.6 & sell or trade them, knowing what you know now & learn this summer with what you have. On a side note, CFM is important. But it really only affects power, an engine is setup to make, within the rpm range as I described in my previous post. You still need to have properly tuned intake runners. The beauty of the tripples is that you can do most of that by changing the choke size, given they're the right size to start with.
  8. Honestly T-Bone028, 40DCOEs are woefully inadaquate(truly not better than the SUs) for the motor you have, particularly with 33mm chokes. But, the flow on them is going to max out with even 34-36mm chokes anyway and still not be anywhere near as good as 45s with the same size chokes. It really needs a set of 45s with at least 36mm(really 38mm) chokes to make the power it's capable of making. Naturally you need to have the timing set up relatively close. Any of the stock distributors set to around 14 degrees at idle will give you 32-35 total mechanical advance. Which is going to be about right, with your cam, depending on your compression ratio. With the cam you have, which I assume is a 270/280 not a 470/280, a 3.1 should make peak power around 6300RPM. But with 33mm chokes, it will peak at around 5600RPM. Some folks think that they will save some bottom end power by putting smaller chokes on their engine. But, all they are doing is shortening their operating range. With a cam of 270 duration, or more, it's not going to make good power below 2200RPM. So, if it's not going to make power until around 2200RPM and peak at 5600RPM, that's 3400RPM of really useful operating range. Or 4000RPM if you take it to 6000RPM or so. When you could have 2200RPM to 7200RPM= 5000RPM. In addition, it will make A LOT more power! The ONLY thing that will make any difference at all, for the low RPM range, is if you have the ovelap reduced on the cam which I recomend anyway. If you don't want to go through the trouble of getting 45DCOE carbs, I would recomend getting a new cam that is made to peak around 5750-6000RPM. I think you will find that it makes the most power, for the least amount of money, with those carbs and the rest of your setup, and the engine will have a VERY strong low RPM range.
  9. This is LSA (Lobe Separation Angle) Generally the closer LSA will give you a better mid range, and less vacuum at idle(rough idle). Torque curve looks like a hump. Wide LSA cams give a flatter torque curve(more like a plateau) and better idle vacuum, which is why injected cars have had them in the past, because they needed the low rpm vacuum to operate the fuel pressure regulator. You can run either on a carbed car, but the carbs will need to be tuned accordingly. This is the single biggest factor in getting a built motor to have a clean idle for smog testing. I should've added, i would agree with jeffp overall. Except with that much lift, i would go for at least 114 LSA. Which i think you'll find is what's necessary to have overlap around 50 with that much lift, but i haven't done the math.
  10. Honestly you really don't need the rising rate fuel pressure regulator, since you have turbo injectors. Unless you fix the main problem with your setup. I'm going to assume the 45 degrees is total=a couple more degrees than stock at WOT for a total mechanical of 30. You should be shooting for, with proper tuning, around 35 total mechanical advance. Aside from that, the main problem is you have an intake manifold that is choking off your engine massively! At least you don't have it listed as modified. The stock intake chokes off a completely stock l28. For your engine you need a custom intake manifold & engine management. Although, you could probably get away with just the new intake manifold if you swapped to a larger AFM, that would better be able to communicate the extra flow to the stock ecu, especially with the bigger injectors, & flow properly for the larger TB. Put an intake on there, with at least 36mm runners, & you will receive a large increase in power from 4000-7000rpm.
  11. The carbs, and how they're set up, need to be matched to the cam primarily. Naturally there's tuning involved for other modifications though. There used to be a little dos program floating around the web that Dave Andrews did up (around 1997 i believe) for the 510 crew that gives the information you need to properly setup a set of DCOEs based on engine size & peak power rpm. I have it saved at home. Anyway, if you want, & have a cam that can provide peak power much above 6000rpm=270+ duration, you're better off with the 45s. The 40s flow capability really levels off above a 34mm choke. It doesn't really matter what cam you have, or carbs really, if you use a 32mm choke, your peak power will occur below 6000rpm. If that's where you want the power to peak at, then you might as well use a stock induction setup, with a stage 1 cam, as that's what they're built to do.
  12. Just save the head .080 & shim the towers. that will get you right around 10 to 1 it's described on the Datsun Z garage website
  13. It will work just fine, it will just have to be tuned differently than the 'carb' cam. Having a wider LSA(Lobe Separation Angle) simply reduces overlap. Most fuel injection systems require vacuum to control the fuel pressure regulator. Otherwise they will over-fuel at small throttle openings, low RPMs and idle, until you reach the bottom end of the cams operating range where vacuum will become 'normal'. With your cam that point would be roughly 3000rpm. Even if you got the timming right, performance would be very average below that rpm because you wouldn't be able to dial out the extra fuel. You didn't have that problem with FI because you had the right cam for it. The other effect of a wide LSA is the rearrangement of the torque curve. Wide LSA cams will produce a plateau shaped curve(slightly better lower and upper rpm), going sharply upward toward lower end of the cams operating range, 3000rpm with your cam, stay relatively flat until peak, 6500rpm again for you, down after that. Narrow LSA produce a mountain shaped curve(better mid-range power), going sharply upward toward peak torque RPM, around roughly 4500rpm with your cam, and sharply downward toward redline. So when your cam with the two different LSAs are compared to each other: Wide LSA= more power 1000-3000rpm, and 5000-7000rpm Narrow LSA= more power 3000-5000rpm There's really been a change in how cams are looked at in the automotive world. A wide LSA cam is better for all applications; street or race, carbed or FI. The only exception being someone who wants/has an automatic(where mid-range power is much more important) and/or wants a 'mean' sounding idle. So, with the carbs you have now, you will tune for that plateau instead of the big bump in the mid-range. Get a wide band o2 setup because everyone elses setup with those carbs(any carbs really) aren't going to work as well for you. I can't help you with those carb settings, because I'm not familliar with that model. But, if they're setup for a stock l28, they won't be too far off. All you will probably need to do is add a little fuel in the full throttle 'circuit', and a slighty smaller accelerator(pump or enrichment) 'circuit' to make it work.
  14. I have a complete 1982 280zx turbo(auto)l28et. When I say complete, I mean everything that is required to run the engine. From ecu, to oil cooler(not sure I have all the copper washers for the oil cooler), to relays specific to the engine harness, including the down pipe. I will include any spare turbo parts I may have, i.e spare, throttlebody to turbo, j-tube. The engine had about 160,000mi on it when pulled from the car(ten years ago), it was started before pulling, and ran without issues. I would recommend replacing the hydraulic rocker pivots, with solid ones(not very expensive or hard to do), but it ran without any obvious ticking from the hydraulics. Also, engine prep for an engine sitting for an extended period of time, priming the oil system etc, should be done. I don't have any compression numbers, but I could probably do that. I bought it with the expectation that I would be able to bolt it up, prep it, and go. So, I believe it will do just that. Cosmetically, it's average, with the only obvious issue being, some of the valve cover paint has peeled. I'm planning on posting this for sale soon anyway, as I need the money to prep my Z for Autox this year, but I saw your post and thought I would give it a shot. I have a 75 I was going to put it into, but decided to stay NA. I'm asking $1000, plus shipping, but am open to offers. I would ship from 98225, as that's where I'm storing it currently, so take that into account. I prefer Pay Pal for payment... Thank you! Ross
  15. ram75280z

    ram75280z

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