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High power L31

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I have a Z31 and I'm thinking of going to a L31 in the far future. i strongly believe the L31 has a ton of potential that hasn't quite been tapped the way it should have as the years past. to a lot of people this may seem like a "down grade the VG30 is proven to make power" it's true but the sad fact is it's a V6 and while the VG30 is built tough as nails it's not up to what i want. it's a very rough motor for the simple that that it was built as a V engine, it wants to tear it's self apart. (easier to go up and pull down and push up then on a vertical).

 

I'd like a 650 - 770RWHP L31ET I was thinking of doing a compound turbo setup (like marcs 2jz Z31 setup) to get these numbers and head work of course (i know someone who does GODLY head work the head won't be a issue). money is not going to be a issue for this build. i need these numbers to be reliable numbers. (obviously NOT on stock internals.)

 

I do need some direction as to where to start? is 9.1 a good compression for the old folk L motor. I heard someone tell me i should go 7.4:1 with godly amount of boost but again i need direction as to what the old design can take, not every motor is the same and some motors like to detonate with high compression and boost.

 

keep in mind this will be a project for the future but it will happen though.

Edited by New 2 z

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I just want to say it took a very long time to read that. Also, terms like "godly boost" don't really help here.

 

I don't know if an rb would be cheaper at that point, but my gut feeling is that it would at least be more reliable. The parts for an L31 would be cheaper, so while it probably wouldn't take as much cash to reach that goal, the motor would have to be stretched pretty much to its very limit, whereas an rb26 and rb30 have taken that kind of heat (and much more) with ease.

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Those horsepower numbers have been achieved a number of times with the L series engine going back as far as the late 1970s with Electramotive. You're looking at around $20K minimum for the total engine build with a single turbo the better option. Spend the next month reading up on this site before spending a dime. Read, read, read before asking any more questions.

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Got to agree, 738RWHP at under 25PSI on a 3.0 (single turbo, BTW.) I don't see the point when the Z31 was designed to run an RB meaning all the swap parts are available from Nissan to do an RB30. On a third front the ability to make a 3.4 Liter VG is child's play and which will easily make the reliable HP desired...

 

You should probably go back and reassess what you thought you knew. You got a LOT of misconceptions about what you "think" you need. Basically I'm parroting what John C is saying. I'm just adding the "Why" because your assumptions about V-Configurations are WAY off-base!

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Hell, I saw a normally aspirated VG30DE at Sunbelt make 425 hp breathing through a 25 or 30mm restrictor. It was one of a half-dozen LMP2 engines for the Nissan sports prototypes running the American LeMans series. The VG30DET engines run in Nissan's GTP 300ZXT made "crazy" amounts of horsepower according to a friend who ran the engine dynos at Electramotive.

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There is a VG33DETT here in town in a full-bodied Z32, full interior, running in the low 9's on the track. Yeah, it's a nice smooth car...but it's a heavy sonofabitch too, so I'm SURE he's making some pretty acceptable power. He street drives the car all summer, too.

 

I don't remember his "numbers" but I do know that he's running the early manifolds with two largish T3's, mostly because it was easier for him to pack it in there that way. That bay is a maze of 2.5 and 4" pipes, intercoolers, fuel lines, wiring, everything.

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kind of bring this back from the thread but after reading many many engine swaps. i love the L for it's reliability I've been reading up and down google search engines and i cannot find one thread where a L has spun a rod bearing (engines fault). or dropped a valve/ something along those lines.

 

the VG's spin bearings this along scares me. and rhw newer DETT's while being a better motor parts are retardly expensive. and i dont feel like buying two of everything.

 

I've seen a L30et make 650hp on e85 and 609hp on pump. and realistically 770hp would be insane to daily drive. looking to make more along the lines of 500hp with the L28ET. i don't see why it would not be reliable daily driving it (off boost.) however I am somewhat new to the L series so i can be way off base too.

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Again, if you want 500HP in a Z31 and you do NOT want the VG, go with the RB. It'll be cheaper, faster, and more reliable.

 

For instance:

 

L28ET full engine swap: about 800$ for the engine+harness, WITHOUT the transmission you'd need to handle 500HP. More on that below. About the same money to completely rebuild an L to the level needed for a reliable 500HP. Looking at 1600$ here, not counting the head work, camshaft, or turbocharger. New turbo sized to make 500HP, add a grand, head work, at least 300$, cam is about 170$ or so to install and setup a regrind. 3170$ in engine work, so far. This does not include getting the engine into the car or getting the turbo plumbed, exhaust routed, fuel injectors, or getting the engine wired up to work. You will also want a tunable ECU at this level. The intake manifold will be a limiting factor at this level, but the stock exhaust manifold is usable with some cleanup work.

 

The RB25DET can be pushed (with very careful tuning) to 500HP in stock trim, and can be reliable...the weak spot is the ceramic turbines. Upping the boost to get to 500HP tends to break them, so a turbo upgrade would be needed. It can be bolted into the car with minimal fabrication...since the car was designed to hold an RB20DE, the mounts, exhaust, pan, etc will all fit. (you'll need either the NLA 200ZR oil pan or a custom pan, though) The ECU and wiring harness generally will come with the engine, and the ECU can be tuned to handle this level of power. No cams, headwork, lower end rebuild, are really required to handle 500HP, nor is a hard-to-find and expensive transmission adaptor needed.

 

The Z31 turbo trans will not hold 500HP. It's the same as the 280ZX turbo transmission. The Z31 nonturbo trans will not hold 500HP. The stock L 5 speed won't hold 500HP. You will need to go to the Z32 transmission, with a bellhousing adaptor, if you choose to go this route with the L31. The RB25 already comes mated to this transmission, so no adaptors needed. I guess you could get a heavily built custom T5 WC transmission and adapt it into the NWC Z31 turbo and 280ZX turbo cases, too.

 

You are saying the L is more reliable than either of these engines...In stock form, sure, I can see that. But once you start pushing 400HP, the L28, as delivered from nissan, starts to get spendy, just like any other engine that has had the power output more than doubled from stock.

Edited by Xnke

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You are very right. the RB is a very good motor, you are very correct about the transmissions too. but how many L30ET's @500hp in Z31's have you seen? lol sure its not as efficient as a RB or VG. yes the Z31 was originally built with a RB design in mind but I just love the old L series as there just is not much to go wrong.

 

I was thinking of a rebello forged bottom end. either way i go I'm going to spend money to get there. I should do it in a way no one has done before.

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