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6G72 in a Z


Guest Dan0myte

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Guest Dan0myte

I did a search for this, but it found absolutely nothing posted on this before.

 

What's the story on the 6G72, found in the Stealth TT and 3000GT VR4? It's an excellent engine, crippled by a weak and expensive AWD drivetrain. Is there the possibility that it could be mated to a RWD transmission and used in the Z? I think there may be a totalled off Stealth TT at the government salvage yard, so that's why I'm asking.

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Guest Dan0myte

That particular example used a Porsche 928 transmission. It's a little strange because the transmission is actually integrated with the rear differential. Essentially, you have a driveshaft attached directly to the engine crankshaft, that then spins a clutch in the rear diff housing. Then you have shift linkages running back there. Sounds like a pain in the butt to do, and expensive too.

 

I was researching the Mitsubishi Pajero today. It came with a 5 speed manual, 4 speed auto or even a 5 speed auto. These were then either RWD, or turned into a 4WD with a transfer case in the middle. I think you may be able to put a Pajero tranny on a 6G72 block and have it RWD.

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from what i read its a heavy motor, plus its really a FWD motor setup stock.

it is pretty strong though, when getting new 500hp the internals start to give away.

im not so sure if its a good idea but im sure it can be done and it would be cool and different.

 

good luck.

 

mike

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Guest MegaShaft_2000
Originally posted by Dan0myte:

Found a pic of a RWD converted 6G72:

Perez2_s.jpg

 

What I like about the 6G is it's engine dynamics. It's the same 3.0 litres as the VG30DETT, but the similarities stop there. The 6G is a 91mm x 73mm engine, while the VG30 is an 87mm x 83mm engine - the 6G will be much more efficient on the top end, with a power band almost resembling an inline engine. Plus, the cooling passages and strength of both the block and rotating parts is much more inclined to high power than the VG. This is expressed most by looking at the amount of work JWT puts into a VG to make it a 600hp engine, while the 6G barely requires any mods..

There are quite a few members on TT.net putting out almost 600 hp at the rear wheels on stock internals. Just turbos and injectors will get you there. Of course you'll end up wanting cams to stretch out the power band a little.

 

I have not seen many high HP Stealths/3000GT's. From what I've heard, it is not a durable powertain, and both the engine and tranny give way early.

 

I have never heard anyone claim that it is a stronger powerplant than the VG30DETT.

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Guest Dan0myte

Found a pic of a RWD converted 6G72:

Perez2_s.jpg

 

What I like about the 6G is it's engine dynamics. It's the same 3.0 litres as the VG30DETT, but the similarities stop there. The 6G is a 91mm x 73mm engine, while the VG30 is an 87mm x 83mm engine - the 6G will be much more efficient on the top end, with a power band almost resembling an inline engine. Plus, the cooling passages and strength of both the block and rotating parts is much more inclined to high power than the VG. This is expressed most by looking at the amount of work JWT puts into a VG to make it a 600hp engine, while the 6G barely requires any mods.

 

I'd much rather have a Nissan engine in a Nissan car, but when you compare Nissan options with those from all the other car manufacturers, it's a tough sell to stay brand loyal.

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Guest MegaShaft_2000

By the way, you seem to have a vendetta against the VG30DETT. On no less than 3 different occasions you have put it down saying it's not as good as the RB26DETT, the 2JZ, and now this Mitsubishi powerplant.

 

Although the VG30DETT engine is in numerous supply and has put out impressive numbers you seem intent on putting it down every chance you get. It's as if you want to steer people away from it.

 

I've already shown you a VG30DETT putting out in excess of 1,200 rwhp, what more do you want? What leads you to believe that the VG is not up to the task of handling high HP?

 

I've shown you the VG putting out 1,200 HP at the rear wheels, now how about you show me a 6G72 putting out more than that to support your claim that it is better suited to high HP.

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Guest Dan0myte

I'm in no way 'putting down' the VG. It's a strong engine in it's own right and like any engine, can be worked to make power. What I am doing is comparing the engines to each other with plain ol' facts and no speculation.

 

Are you saying the bore x stroke numbers listed are wrong? Are you saying that all the dyno curve printouts on the internet are fakes? I don't see any possible arguement against those points.

 

As for finding a 1200hp 6G72, it's slightly unfair. The TT engine only found it's way into the Mitsubishi GTO (3/S), which actually has smaller drivetrain components than it's talon/eclipse siblings, and begins to break down constantly at those kind of power levels. The Getrag tranny alone is a $5000 replacement part, and no one makes parts to fix them. No one that I know of has built the 6G into a tube frame car either, but just because no one has had a huge company fund a $100,000 drag car yet doesn't mean it isn't possible.

 

I think Bob H mentioned this to you already, but please stop turning debates on opinion into personal attacks.

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Guest MegaShaft_2000
Originally posted by Dan0myte:

If you'd like comparions to another engine, the 2JZ-GTE head has a stock flow rate of 220cfm, while the 6G72 head has a stock flow rate of 260cfm.

That's an interesting fact. I need to find out what the stock flow rate of the VG30DETT heads are. From what I hear, though, in stock form it's less than the 2JZ or RB26DETT head.
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Guest MegaShaft_2000
Originally posted by Dan0myte:

What I am doing is comparing the engines to each other with plain ol' facts and no speculation.Are you saying the bore x stroke numbers listed are wrong? Are you saying that all the dyno curve printouts on the internet are fakes?

No I'm not disagreeing with the specs you quoted. And I'm not saying that's it's a weak engine either. I was just asking what made you think it was stronger than the VG.

 

Here's the part that I find suspect: "the cooling passages and strength of both the block and rotating parts is much more inclined to high power than the VG"

 

I'm not claiming that the VG breathes better or anything of that nature, I'm just wondering what makes you think the block of the 6G72 and its rotating parts is much more inclined to high power than the VG.

 

I only brought up the 1200 hp Z to show you that the block is obviously strong enough to take it, and since that engine is using the stock crank you know that its main rotating part can take the power too. The stock internals of the VG30DETT can take at least 600 rwhp (700+ at the crank).

 

So what I'm asking for is some evidence pertaining to the strength advantage of the 6G72 over the VG. Please point out the weak points you see in the power handling ability of the VG.

 

Thanks.

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Damm the internet! I just dumped my response b/c I suck at the internet....argh...

Ok, keeping to facts, and backing up the facts...

I take some issue with the following statement:

The 6G is a 91mm x 73mm engine, while the VG30 is an 87mm x 83mm engine - the 6G will be much more efficient on the top end, with a power band almost resembling an inline engine.
That is a very broad statement that I feel holds no water. First, what is meant by "more efficient on the top end"? Efficient can mean a number of things, better fuel mileage, less power, more power, etc.. To claim it is because of the stroke/bore design excludes a huge number of important factors as to how much power is produced. To me it is the same as saying, "The RX-7 has 260 hp and the Chevy Tahoe has 285hp, so the Tahoe is faster". Obviously there are more factors involved as to which is faster.

But assuming you mean produces more power higher in the rpm range, I'm not sure I agree.

The stock figures for the 6G motor say 300 hp at 6000 rpm vice 300hp at 6400 rpm in the VG30dett. And with respect to torque, it is 307@2500 in the 6G vs 283@3600 in the VG. That indicates to me that the 6G is more of a "grunt down low" type motor vice the VG.

I believe you are aluding to a bigger bore allowing more potential use of the valves to bring in air and fuel. However there are about a million other things that feed into that. And long stroke motors tend to produce more torque and at a lower rpm, but that depends on rod length, compression ratio, combustion chamber design, camshaft specs, etc.. As you can see, the 6G has a shorter stroke, but produces more torque....

If we are going to compare one type of motor,(or make of motor), to another, please address all the variables, otherwise it is a useless excercise.

And lets drop the I said, you said from the posts. All it does is focus on what the person said vs what was said. Noone is innocent here.

-Bob

edit:

ps- shoot, forgot to add one thing I had in the first post. You asked about putting the 6G into your car. Sure, you can pick up the motor fairly cheap, however it will not be a cheap or easy swap. Just take a look at the guy who was talking about putting the 928 setup in his car.

You will find the 6G, while possibly being a great motor, will be very hard to adapt to a RWD platform. What are your overall goals? Do you want a certain HP? Are you drag-racing, road-racing, daily driving? Is it just a WOW factor? If you are fairly sold on the Mitsu. motors, I say go with the 4G63 motor as they have been adapted to RWD in several ways. Read the post in the alternate forum,(well this one), about putting a 4G63 stroker into a Z. Good power, very light weight, good combo.

Your goals will help others identify what might fit your needs.

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Guest Dan0myte
Originally posted by Bob H:

The stock figures for the 6G motor say 300 hp at 6000 rpm vice 300hp at 6400 rpm in the VG30dett.

True, but you have to factor in turbo specifications. The T25's found on the Z32 may stay in their efficiency range longer, while the tiny TD04-9B's on the Stealth will die out past 6000.

 

Originally posted by Bob H:

And with respect to torque, it is 307@2500 in the 6G vs 283@3600 in the VG. That indicates to me that the 6G is more of a "grunt down low" type motor vice the VG.

Again, could be attributed to the instant spool of the 6G's smaller turbos. Possibly could be head design too? I'm just speculating here.

 

Originally posted by Bob H:

You asked about putting the 6G into your car. Sure, you can pick up the motor fairly cheap, however it will not be a cheap or easy swap. Just take a look at the guy who was talking about putting the 928 setup in his car.

You will find the 6G, while possibly being a great motor, will be very hard to adapt to a RWD platform. What are your overall goals? Do you want a certain HP? Are you drag-racing, road-racing, daily driving? Is it just a WOW factor?

All things considered, it probably just wouldn't be cost efficient to use the 6G72, and I can see why it hasn't been attempted before. It's an excellent engine, but just expensive and time consuming to attempt. Plus, I would really like to keep the 240 an inline-6 car. It's what the Nissan engineers designed it for and it's what I believe would make it a better 'supercar'.

 

My car will be a 'summer fun' only car, which will be street driven, but probably not on a daily basis. The car won't be used for any road racing, and auto-x would be minimal. The main platform for competition would be drag racing.

 

So far, the fastest imports at SIR raceway here have been in the low 12 second range. I'm hoping for this car to become the first to break into the 11's, completely import powered. No american parts allowed in my car. :D

 

Originally posted by Bob H:

If you are fairly sold on the Mitsu. motors, I say go with the 4G63 motor as they have been adapted to RWD in several ways. Read the post in the alternate forum,(well this one), about putting a 4G63 stroker into a Z. Good power, very light weight, good combo.

A 4G63 would be a fairly easy way to go for me. I'm one of the founding members of SaskDSM (http://sask.dsm.org) in 1997 and have worked on the 4G extensively since. Last year I got a JDM motor set and swapped that in, ended up with a 13.2 quarter mile before some unfortunate incidents.

 

I feel like I've done enough work on the 4G's though, so I'm looking to get into a 6 cylinder import engine, while at the same time moving to a car that weighs 600 pounds less than my Talon. Plus, a 4 cylinder just looks kind of goofy under the hood. smile.gif

 

1549200z.jpg

 

Nissan FJ20. Excellent engine and brutishly strong, but just seems wrong to transplant something like that into a Z.

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