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vnoriginal

V6 vs i6 vs v8 swap (280z)

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I want to try to do an engine swap in my 280z, hopefully to a vr38dett from a nissan gtr.. Does anyone know if this is possible? The engine is a 3.8 v6 if you didnt know. I havent seen anything about anyone trying it before.

 

If that doesnt work, id do an rb26(i6), or an ls1(v8). Opinions:thoughts/knowledge is appreciated.

Edited by vnoriginal

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Wow! well a VR38DETT would be awesome, but do you have $25 Grand sitting around to drop on the motor?  So far as I know, nobody has done that. Though there's some obvious issues beyond the price tag, first the Tranny,  you'd probably have to use a different transmission.  I believe the GTR transmission is an AWD, and may have components built into the VR30 block, so AWD swap may be required.  Which is a whole new issue.  I don't know if the 370Z tranny would bolt up or not. In either case you'd also need the Engine electronics. Though you may be able to get the engine running on 370z electronics, you'd still have a lot of tuning changes to account for the Turbos.  That's issue number two. The Turbos on the stock VR38DETT are in close by the the sides of the engine, But that's really tight by the frame rails of the S30. So body mods would certainly be required.  Lastly, the S30 steering shaft is a tight fit with all the VQ engines. I'm certain it would be quite tight with the VR.  So aside from those issues, the VR38DETT should be possible and something I'd LOVE to see in an S30.  The VR38DETT is one DAMN SEXY engine.  The Intake plenum is being adapted to the VQ engines, but I don't believe it's been released yet. I'd love to have that at least.

 

Now other engines, Well the VQ35 has been done a few times and is a proven swap. The McKinney mounts should work fine for both the VQ35 and VQ37's  Read my VQ swap primer for more information.  VQ's are solid proven engines that best of all fit behind the front steering crossmember (w/ mods)

 

The RB's RB20, RB25, and RB26 are very good engines, but they're much older and the parts to swap (oilpan) are all but impossible to find, many people fab their own now. They can produce amazing power, but stock not that much more than a VQ37HR. Turbo'd the power numbers are apple to apples about the same. BUT the VQ is lighter.

 

2Jz etc, These are also nice engines, much better supported these days than the RB's but these are toyota engines too. The power and other specs are very similar to the RB. but they are also lighter. 

 

V8's  well there's a ton of engines that'll fit.  The S30 was originally designed for a V8, but the gas crunch and american emissions limited the S30 to the straight 6 that it got, but it fared VERY well with the "L" engines.  The LS engines are awesome, and pretty easy to fit. it's a matter of personal choice v8/v6 on that.  In the end it's your car and especially it's your $ so you do what you want, we will try to help...

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 The S30 was originally designed for a V8, but the gas crunch and american emissions limited the S30 to the straight 6 that it go

Not true, S30s were always intended to come with a straight six.

 

 

As for a swap, for a six cylinder i'd go with either a VG or VQ engine. Parts are relatively cheap and easy to come by for both engines. If I was going V8 it would be a VH45DE. Still a Nissan engine and it makes 300HP stock and can make 350+ with just bolt ons. VHs can be had for a few hundred bucks from your local junk yard and with an adapter you can use either a Z32 or Z33 manual transmission.

Edited by RedBeauty84ZX

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Hmm I thought sure I'd read that somewhere they designed the Z so that later a V8 would be easy to drop in.  I just spent a couple hours searching but could not locate where I'd read that. I assure you I didn't just make up that idea.  I know Nissan was directed on which engines to fit under the hood. I just haven't found where they'd mentioned the V8 as a possible choice. If I come across where I'd read it, I'll be sure to post it.

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This seems almost shed worthy, but I'll go ahead and say my piece anyways.

 

Goals goals goals!!! You haven't stated much in that respect, and from what I can tell you probably don't even know what your goals really are, even if you THINK you do... From what I can read, all you really care about is having a decent amount of power and being cool. If you're TRULY considering all three of those engines as a viable option, then maybe you're open minded enough to hear what I have to say.

 

Let's talk about the ASPECTS of what makes an engine a worthy choice for someone, or the aspects that make an engine a good PERSONAL FIT. At the end of the day it's an emotional choice, and that's OKAY, and even worth defending. On some level I LOVE ford small blocks, and I'm okay with that. I LOVE the new Coyote too, and that's okay as well. That doesn't make them BETTER for someone ELSE though. But cutting through all the crap, here's what matters.

 

1. Package

 

This is a big deal, and OEM's spend tons of money finding better ways to package EVERYTHING, including engines. The goal is to keep things compact, light, low, and back (regarding FR layout engines).

A V6 is technically going to fit these requirements much better than the common options. The fact it's a V arrangement means that the cylinders and heads are slanted, bringing the weight down towards the ground. The fact it's only 3 cylinders long mean that it's also going to be a short length motor too, so all in all a V6 is going to be a VERY compact package.

A V8 is great if you are happy with the layout of a V6 but want more displacement for more power potential (all things being equal). Instead of making the pistons of the V6 MASSIVE, which would increase vibration, which is kind of a big no-no these days) you add some cylinders and tada! The LS1 in discussion here is a very compact arrangement, with valve covers MUCH lower than the valve cover of the stock engine, and the end of the block ending MUCH further back, even with the back of the block more forward than necessary to match the stock L28 mounting.

A I6 motor is extremely hard to package well, and really isn't it's strong suit. If you want to see a well packaged I6, look at modern (I'd say post 1990 as a general rule) BMW I6 vehicle. BMW tilts the motor over like crazy to get the weight shifted towards the ground, and make everything as compact as possible. At the end of the day, the weight and size of a I6 is pretty intense compared to the displacement, and thus the average power output for a given configuration.

 

2. Valve Arrangement

 

This might not sound like much of an issue regarding choosing an engine, but it REALLY IS!

 

Pushrod engines keep the camshaft buried in the block and use rods to push rockers that open the valve. The upsides to this are actually pretty huge. It means the head itself can be kept very small and light, and they don't add much of any noticeable mass to the block. There's even a handful of popular pushrod I6 engines like the Jeep I6 4 liter that was used for a millennium. The downside to pushrod motors is that it's extremely difficult to package more than 2 valves per cylinder, with will make it difficult to maximize power potential per cubic inch. Pushrod engines rarely approach overhead cam designs in regards to power per cubic inch unless they're highly modified, to a point that some would call them unreliable even. The upside that counters that is that because the heads are so compact you can make the block much bigger for a given package size, which is a big reason GM & Chrysler kept with the pushrod design. The modern pushrod engines are still some of the most powerful engines per pound of assembled engine, rivaling even the most high strung performance DOHC engines on the market.

OHC engines are engines with camshafts that are nested inside of the head, instead of the block. They can still use lifters and/or rockers of sorts (like the Nissan L engine) to act upon the valve. There's also directly acting setups with arrangements like "cam on bucket". Some feel that directly acted upon valves are better for higher RPM use, but my personal opinion is that it all comes down to design and application. If you engineer a SYSTEM to work at a particular design range, then it'll work just fine, hence NASCAR using a pushrod design that reaches 10k rpm, or guys with nissan L engines that go BEYOND 10k. Ford's new Coyote probably has the best valvetrain of any DOHC V8 engine built, and it uses a rocker arrangement, because it keeps it more compact. There's so many variants of OHC setups that I really don't want to cover it, but I'll just say there are MANY things about head design that can become a factor when choosing an engine to swap.

 

3. Availability

 

How many cars did the engine come in? How hard are they to source? Some people like being able to buy parts at any auto store, while others are perfectly fine having a small collection of spare bits, should something go wrong. The LSx engines were installed in probably going on to MILLIONS of vehicles. Just about everything they make has a LSx option. The RB is somewhat high on this list, as far as imported engines go, but I'd still not call it highly available. The 2JZ is much more available, as there's quite a lot of Toyota vehicles that came with them in NA form.

 

4. Cost

 

This is strongly affected by the previous section, but it's also effected by many other factors too. Is the conversion easy? Because if it is then the costs other than the engine itself will be lower. Can you find a whole donor for cheap, reducing costs on misc parts? Don't just look at initial engine cost. Last person with a SR20DE swap I met, I asked how much they spent on the swap, and they said around $3500.... You realize I did NOT say it was the turbo right? Those engines pop up on ebay WITH TRANS for sub $800 prices at times, yet his swap costs were more than TRIPLE that! Don't just look at a price on craigslist and assume you can complete the swap for "not much more". You WILL run into unexpected problems and you WILL have to find solutions, and the easy ones usually cost more.

 

5. Cool Factor

 

This can be anything and it is everything. I can meet someone who put a Ford slant six in their car because they really wanted to, and you know what? That's alright. As long as that person recognizes that it's not because the Ford slant six is "the best" then we can get along just fine.

 

6. Other

 

I included this because there's always other factors at play. Say a family relative wreaked their hyundai genesis and you decided to pay the buyback from their insurance so you could use it as a donor car. Or maybe you want to have a force induced motor, and you don't want to convert a NA engine, so you're just looking at factory force induced engines. All kinds of things can cause a decision to be influence, and at the end of the day the only thing that makes it invalid, is you.

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Not true, S30s were always intended to come with a straight six.

 

 

As for a swap, for a six cylinder i'd go with either a VG or VQ engine. Parts are relatively cheap and easy to come by for both engines. If I was going V8 it would be a VH45DE. Still a Nissan engine and it makes 300HP stock and can make 350+ with just bolt ons. VHs can be had for a few hundred bucks from your local junk yard and with an adapter you can use either a Z32 or Z33 manual transmission.

Probably a long dead thread but do you know if the adapter plate you mentioned is available manufactured anywhere?

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This seems almost shed worthy, but I'll go ahead and say my piece anyways.

 

Goals goals goals!!! You haven't stated much in that respect, and from what I can tell you probably don't even know what your goals really are, even if you THINK you do... From what I can read, all you really care about is having a decent amount of power and being cool. If you're TRULY considering all three of those engines as a viable option, then maybe you're open minded enough to hear what I have to say.

 

Let's talk about the ASPECTS of what makes an engine a worthy choice for someone, or the aspects that make an engine a good PERSONAL FIT. At the end of the day it's an emotional choice, and that's OKAY, and even worth defending. On some level I LOVE ford small blocks, and I'm okay with that. I LOVE the new Coyote too, and that's okay as well. That doesn't make them BETTER for someone ELSE though. But cutting through all the crap, here's what matters.

 

1. Package

 

This is a big deal, and OEM's spend tons of money finding better ways to package EVERYTHING, including engines. The goal is to keep things compact, light, low, and back (regarding FR layout engines).

A V6 is technically going to fit these requirements much better than the common options. The fact it's a V arrangement means that the cylinders and heads are slanted, bringing the weight down towards the ground. The fact it's only 3 cylinders long mean that it's also going to be a short length motor too, so all in all a V6 is going to be a VERY compact package.

A V8 is great if you are happy with the layout of a V6 but want more displacement for more power potential (all things being equal). Instead of making the pistons of the V6 MASSIVE, which would increase vibration, which is kind of a big no-no these days) you add some cylinders and tada! The LS1 in discussion here is a very compact arrangement, with valve covers MUCH lower than the valve cover of the stock engine, and the end of the block ending MUCH further back, even with the back of the block more forward than necessary to match the stock L28 mounting.

A I6 motor is extremely hard to package well, and really isn't it's strong suit. If you want to see a well packaged I6, look at modern (I'd say post 1990 as a general rule) BMW I6 vehicle. BMW tilts the motor over like crazy to get the weight shifted towards the ground, and make everything as compact as possible. At the end of the day, the weight and size of a I6 is pretty intense compared to the displacement, and thus the average power output for a given configuration.

 

2. Valve Arrangement

 

This might not sound like much of an issue regarding choosing an engine, but it REALLY IS!

 

Pushrod engines keep the camshaft buried in the block and use rods to push rockers that open the valve. The upsides to this are actually pretty huge. It means the head itself can be kept very small and light, and they don't add much of any noticeable mass to the block. There's even a handful of popular pushrod I6 engines like the Jeep I6 4 liter that was used for a millennium. The downside to pushrod motors is that it's extremely difficult to package more than 2 valves per cylinder, with will make it difficult to maximize power potential per cubic inch. Pushrod engines rarely approach overhead cam designs in regards to power per cubic inch unless they're highly modified, to a point that some would call them unreliable even. The upside that counters that is that because the heads are so compact you can make the block much bigger for a given package size, which is a big reason GM & Chrysler kept with the pushrod design. The modern pushrod engines are still some of the most powerful engines per pound of assembled engine, rivaling even the most high strung performance DOHC engines on the market.

OHC engines are engines with camshafts that are nested inside of the head, instead of the block. They can still use lifters and/or rockers of sorts (like the Nissan L engine) to act upon the valve. There's also directly acting setups with arrangements like "cam on bucket". Some feel that directly acted upon valves are better for higher RPM use, but my personal opinion is that it all comes down to design and application. If you engineer a SYSTEM to work at a particular design range, then it'll work just fine, hence NASCAR using a pushrod design that reaches 10k rpm, or guys with nissan L engines that go BEYOND 10k. Ford's new Coyote probably has the best valvetrain of any DOHC V8 engine built, and it uses a rocker arrangement, because it keeps it more compact. There's so many variants of OHC setups that I really don't want to cover it, but I'll just say there are MANY things about head design that can become a factor when choosing an engine to swap.

 

3. Availability

 

How many cars did the engine come in? How hard are they to source? Some people like being able to buy parts at any auto store, while others are perfectly fine having a small collection of spare bits, should something go wrong. The LSx engines were installed in probably going on to MILLIONS of vehicles. Just about everything they make has a LSx option. The RB is somewhat high on this list, as far as imported engines go, but I'd still not call it highly available. The 2JZ is much more available, as there's quite a lot of Toyota vehicles that came with them in NA form.

 

4. Cost

 

This is strongly affected by the previous section, but it's also effected by many other factors too. Is the conversion easy? Because if it is then the costs other than the engine itself will be lower. Can you find a whole donor for cheap, reducing costs on misc parts? Don't just look at initial engine cost. Last person with a SR20DE swap I met, I asked how much they spent on the swap, and they said around $3500.... You realize I did NOT say it was the turbo right? Those engines pop up on ebay WITH TRANS for sub $800 prices at times, yet his swap costs were more than TRIPLE that! Don't just look at a price on craigslist and assume you can complete the swap for "not much more". You WILL run into unexpected problems and you WILL have to find solutions, and the easy ones usually cost more.

 

5. Cool Factor

 

This can be anything and it is everything. I can meet someone who put a Ford slant six in their car because they really wanted to, and you know what? That's alright. As long as that person recognizes that it's not because the Ford slant six is "the best" then we can get along just fine.

 

6. Other

 

I included this because there's always other factors at play. Say a family relative wreaked their hyundai genesis and you decided to pay the buyback from their insurance so you could use it as a donor car. Or maybe you want to have a force induced motor, and you don't want to convert a NA engine, so you're just looking at factory force induced engines. All kinds of things can cause a decision to be influence, and at the end of the day the only thing that makes it invalid, is you.

Thanks for this bkgd - very informative.

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