datsphilly
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Posts posted by datsphilly
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very cool, kind of a gamble ordering a no name set of heads off of ebay, im curious, dr hunt, with so many established aftermarket heads why you'd even try these out?
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This thread is now an official "Internet Engineering Masturbation Exercise."
Keep stroking boys...
LOL no pun intended?
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Also if you have the money to rebuild a motor, you've got the money to not rebuild it and go turbo.
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I dont think youll see over 200 to the wheels with aforementioned mods, but with your 4 speed and that 3.90 rear, it will be a fun zippy car.
What flatblackz meant was instead of doing all that work you could retrofit a zx turbo setup on your motor and be even faster, also you'd probably be on the road quicker than all that machining.
Use the search button at the top and try to find a list of all the datsun transmissions and thier gear ratios. If i remember correctly the 260 has the most aggressive gearing and coupled with the 3.90 and a 26" or smaller tire you'll have plenty of fun with your z. Believe me, its never enough, and after enough reading and watching videos and getting to know more z guys, you'll want more.
Welcome to the club, congrats on your first Z.
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Continuing my train of thought from above, if I was building a 383 stroker and had the option of running 6 inch rods as opposed to 5.7's why shouldn't I? Why does the option even exist if its just "scuttlebutt" as my old buddy Colonel Potter used to say?
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read this. there are lots of articles like this.
http://www.hardcore50.com/Articles/georgeklass/greatmyths.htm
Although i have the utmost respect for George Klass, and have used his accufab gear on almost every late model Mustang I've been able to (the ones we ran with e.f.i, that is), I have to respectfully say hes beating around the bush, on purpose. no one is debating that more cubic inches will make more power than less cubic inches, apples for apples. But what rod stroke ratio effectively does is allow for the other half of the horsepower equation to be magnified. That, of course, is RPM. Ask Mr Klass straight up if a higher rod stroke ratio decreases lateral pressure on the cylinder walls, and if a higher rod stroke ratio will, all else being equal, allow an engine to rev more freely, more quickly, and ultimately, to a higher rpm. He will undoubtedly say yes, and yes. Since we are talking about motors whose "stroker" potential pretty much ends at about 10 percent increase in displacement, we need to compensate with revs to make more power. There are a few ways to do that effectively and prolong engine life, one of which is increasing rod stroke ratio.
To go a step further, using Mr Klass' train of thought. Everyone considering building an L series motor is wasting thier time and money because for similar maching shop and parts costs they can have a 410 inch small block ford, or a 412 inch small block chevy.
I have long been a proponent of "more cubes, stupid" as an answer to anyones "how do i make more power?" questions. There are small groups of people on this board and in motorsport who are limited to certain displacements for fear of weight penalty or class change and they are mostly who this thread tailors to. I guess I'm not arguing Mr. Klass' point, I'm more arguing that its irrelevant in this specific thread.
Sorry, that was a bit of a rant.
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I know theres alot of info on this particular subject, a guy on this board is currently going through the labors of installing a merc head from a much later L6 mercedes on his motor now. If you search for merc twin cam head I am sure his progressively updated thread will show up.
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Oh, and Raami, are those pistons "off the shelf" for the L28?
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This thread has grown into a pretty big pile of info on the topic, and its interesting to see how many different combinations are out there to achieve a similar goal... Thanks go out to all who contribute. Raami, what do you usually spin your motor to? What valvetrain mods, if any, do you have to support the extra revs?
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Also, KOM are those pistons from any vg30 motor? Or specifically a vg30de dett? Is there even a difference?
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Never heard of using the 138mm toyota rods, the vg30 pistons are the appropriate hieght for use with those rods? Very cool.
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haha well.....if your going for a race application then why not have a custom crank built?? I mean if your going to take it all the way go have a company like SCAT build you a custom counterweighted crankshaft. I mean if we are talking race motors here we could go this far =P
I like Garrett76zt's build as well...overbore to 89mm, L24 rods and custom pistons with a stock L28 crank. I wonder if you could actually go further than that...f you can get close to 138mm rods you'll approach that "perfect" rod/stroke of 1.75. It just depends on how short you can get the custom pistons I guess (I wouldn't know the minimum you could go, I guess it would depend on whether you were NA or boosted as well).
well theres something i didnt know, i thought the higher the rod stroke ratio the better, whats all this 1.75 business?
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thanks for the input guys, youve been very helpful, as usual.
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A slight improvement in det. resistance won't make up for a 16% increase in displacement.
well then i guess that begs the question, how much detonation resistance is evident with higher rod stroke ratios and is it in fact significant enough to build a street engine towards this goal?
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400 cc of displacement is neither here nor there when we talk about turbocharging.
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im curious why more emphasis isnt put on turbocharging L24's if this rod stroke ratio is such a factor in detonation, i know in the early days prior to the L28et and the F54 and the P90 guys were turbocharging L motors and making good power, why wouldnt a flat top L24 with head tricks makes as much, if not more, power safely than the L28?
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bad ass... pics of the old cartech setup?
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crap. sorry. again thats alot of questions but its just stuff either im too dumb to find or hasnt been asked... probably the dumb me part.
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also, has anyone used an L24 crank instead of longer rods to achieve a better rod/ stroke ratio? some thing like a destroked small block chevy? the reason i ask is the L24 crank is about 5.5mm less stroke than the L28 while the L24 rods are only about 2.5 mm longer than the L28 ones... i guess this would require custom pistons to keep the same deck clearance at TDC ?
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thanks for the explanation, that makes perfect sense. any insight as to what rod lengths are readily available for the L28? is the L24 the "go to" rod for increasing my rod/ stroke ratio, or are there other ones i can use?
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hey all, been reading here and abroad and occasionally find mentioned that a larger rod/stroke ratio ( typically 1.8:1 or greater) somehow reduces detonation... im a pretty smart guy but dont immediately see how the two things correlate, some essplaining would be nice from some of the seasoned L motor builders on the board as to not only the science behind it, but the piston/rod combinations that can achieve a ratio in this range. the project i have in mind is a fuel injected L28 but im sure the theory applies to all four stroke internal combustion engines.
ive noticed also from reading here that the threashold for pump gas L motors seems to be 11:1 compression ratio and im curious to what extent carbs vs fuel injection was used to come to that medium.
also i recently moved to california (thanks to the us army) and theres only 91 octane available here, as opposed to 93 back home in miami. can two octane points really make a dramatic difference in detonation?
damn, that turned into a much more complicated post than i originally hoped... any insight would be greatly appreciated. thanks in advance.
-philly
Hypereutectic Cast Pistons
in Nissan L6 Forum
Posted
thats the moral of the story... id rather be out 300 bucks for cast ITMs from 1 fast z than 700 bucks for forged ross pieces from MSA. bottom line, i think under 350-400 hp if you beak one, youll probably have broken the other with your poopy tuning skills.