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Thread: Josh's 280Z VG30DE 5-speed swap!

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    Default Josh's 280Z VG30DE 5-speed swap!

    I have decided to go through with a swap I have been contemplating for a long time. I am documenting the swap on Northwestnissans.com, and I figured I would do the same on here!
    _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

    So... The L28E that came with my car is in pretty poor shape, sort of. Never been machined before, which is good, but the measurements are all over the damn place. I don't have the money to do that (Please don't point out the cost of the swap, I already know... haha). Basically, I have an entire 1990 300ZX just sitting here, and I would really like to use it. I'm a professionally trained auto-tech, I can use a wire-feed fairly well, and since my dad is basically a master machinist, fabrication isn't going to be a huge issue either. I'm planning on picking up an OBX LSD and clean it up, custom aluminum driveshaft, probably a custom shifter assembly, etc...

    If anyone feels that they have helpful information on this, feel free to reply!

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    So, It's going to get the Z32 5-speed, 80-83 R200 3.900:1 final drive, and 195/60 r15 tires. Also, I'll fit an Autometer electric speedo and tach, and other gauges.

    Need to figure out how to compensate for the shifter on the Z32 5-speed being an extra 5.5 inches farther back, and of a different design, as well...

    The car will have about 235-240 hp, weigh about 3100lbs (200lbs lighter than my 2+2 z32 was), and I chose that tire size/diff gear set because I'm looking to get as close to the Z32's final drive as possible. The tires should give the final drive gear reduction enough of a boost to allow for a little better acceleration than the N/A 300zx, but also be geared high enough to keep the fuel economy close to what the L28E L-Jetronic FI has.

    The thing won't be a race car, but it won't be horrible either. Plus, I will be able to swap a VG30DETT directly into the car later on. I'm also keeping the L28 mounts in the car, to be able to swap the original motor back into the car.

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    classiczcars is a great site but this one might fit your project better - HybridZ
    1976 280Z, with some minor modifications

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    I understand that, I just wanted to let people know what I'm doing on here. Plus, the questions I would need to ask would be ones that people here would be able to answer.

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    Also posting about this build on HybridZ.com

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    Quote Originally Posted by pureZero View Post
    I'm also keeping the L28 mounts in the car, to be able to swap the original motor back into the car.
    Do you mean the mounting points in the chassis? The crossmember and rear engine mount support are removable. These could be modified to suit the V6 without effecting the structure of the car.

    Goodluck with your project
    Looking forward to seeing some photos.
    Chas
    Chas
    5/77 280Z HLS30 403100 with some modifications
    Original colour: 305 Light Blue. The PO changed it to Red

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    I want to mount the VG as far back in the engine bay as possible. The motor isn't light, and weighs about 200 lbs more than the L28, so the farther back it is mounted, the less it will affect weight distribution.

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    Quote Originally Posted by EuroDat View Post
    Do you mean the mounting points in the chassis? The crossmember and rear engine mount support are removable. These could be modified to suit the V6 without effecting the structure of the car.

    Goodluck with your project
    Looking forward to seeing some photos.
    Chas
    If I can add something to them to make it work, then great, but It's still going to be mounted as close to the firewall as possible.

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    As far as the exhaust... I will be whipping up a set of 2.25" custom headers using the mating surface off an extra stock set. After that will be 2.25" straight-pipe with twin glass packs. The step down from 2.5" to 2.25" exhaust should actually give the motor a little bit of a performance, since it will keep the exhaust gasses a hotter than the larger size, making it flow faster.

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    Quote Originally Posted by pureZero View Post
    As far as the exhaust... I will be whipping up a set of 2.25" custom headers using the mating surface off an extra stock set. After that will be 2.25" straight-pipe with twin glass packs. The step down from 2.5" to 2.25" exhaust should actually give the motor a little bit of a performance, since it will keep the exhaust gasses a hotter than the larger size, making it flow faster.
    I don't think you have a very solid grasp of exhaust dynamics. FWIW: Exhaust Tube Sizing: I did your Arithmetic for you!! - Exhaust - HybridZ
    2/74 260Z

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    I am pretty sure I do... The stock 2.5 inch tubing size can support a little over 1000 hp, as proven by Z1 Motorsports on their widebody Z32. Now... Do I need that big of exhaust? No. The fact of the matter is this... What do motorcycles have done to their exhaust to improve performance? Low-restriction, high flowing exhaust. Now, that doesn't mean that a larger size is put onto the bike. There are times that a smaller tubing size is preferred. Tubing size actually has a huge effect on how well exhaust gasses flow. Too small, and there isn't enough space. Too large, and the gasses cool off too much to flow well.

    A higher flow capacity doesn't equate to better flow. Actually, it can be quite the opposite. Yes, if one were to take, say, a V8, and build it for max output, a larger exhaust will most likely be needed. But does that mean that stock exhaust size is the lowest you want to go? With the VG30DE, a smaller size exhaust, with very little restriction, is more than capable of supporting the motor's output. It could actually improve the performance, because the exhaust gasses may be able to flow better. Without any real restrictions, the 2.25" exhaust should, at the very least, flow just as well. The correlation between flow capacity and actual flow only exists when the engine's pumping capacity is taken into account. Theory is great, but it needs to work in the real world, or it's just theory.

    Lastly, remember that I'm not working with a turbo motor. Yes, larger exhaust after the turbine can help it spool better, but it's the complete opposite when working with natural aspiration.
    Last edited by pureZero; 06-24-2013 at 10:38 PM.

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    I think that LeonV might be just disagreeing with your premise that restricting flow "should actually give the motor a little bit of a performance". That's been shown to be an urban legend, wive's tale, myth, etc. when referring to primary size for headers.

    You might be confusing your turbo principles with NA principles. You want hot gases in to the turbo so that they can do work on the turbine. With NA you want cool gases so that they take up less space and get out faster.

    Your vocabulary seems to be outpacing your knowledge. Actually doing something is the best way to learn.
    1976 280Z, with some minor modifications

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    Cool gases exit the exhaust faster...? Okay... Tell you what, If you can prove to me that cool exhaust is better on a N/A, I'll believe you. Give me some irrefutable proof, please. Bigger isn't always better...

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    And apparently, I was mistaken on the stock exhaust size for the z32... It's already 2.25. Any smaller than that, and there'll be some performance issues. I'll still be making my own headers, instead of relying on the stock parts.

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    Thanks for the lesson. I'm guessing you didn't read the link I posted?
    2/74 260Z

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    Quote Originally Posted by Zed Head View Post
    Your vocabulary seems to be outpacing your knowledge. Actually doing something is the best way to learn.
    Zed, I agree, its just my wallet has trouble keeping up with my thirst to learn.

    On another subject. I still can see why the transmission shifter is so far back (shifter is 5.5" back). Is it a FS5W71C? If so the rear mount is only 1" further back and the shifter is in approx the same place. This would put the rear of the engine in the same place as the L6 engine. The V6 length being roughly three cylinders shorter would shift the centre of gravity to the back.
    Chas
    5/77 280Z HLS30 403100 with some modifications
    Original colour: 305 Light Blue. The PO changed it to Red

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    Quote Originally Posted by LeonV View Post
    Thanks for the lesson. I'm guessing you didn't read the link I posted?
    I did, but seriously... I promise you that I am not blowing smoke here (no pun intended). Hot gases tend to move faster through the exhaust. Yes, exhaust will cool off as they move through the piping, but it needs to stay hot for a little while.

    And I'll stick to going with 2.25", thanks though. Just having mendrel bent tubing, no cats, and free-flowing headers will be a huge help to the engine. It's not that I'm trying to tell you that you're wrong, but I am going with what I know, and the link didn't really go into how to apply the information.

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    Quote Originally Posted by EuroDat View Post
    Zed, I agree, its just my wallet has trouble keeping up with my thirst to learn.

    On another subject. I still can see why the transmission shifter is so far back (shifter is 5.5" back). Is it a FS5W71C? If so the rear mount is only 1" further back and the shifter is in approx the same place. This would put the rear of the engine in the same place as the L6 engine. The V6 length being roughly three cylinders shorter would shift the centre of gravity to the back.
    I have the FS5R30A. I can't get anything else either. I'll have to get what I already have to work.

    The FS5W71C came with the Z31, and I have a Z32, which came with the FS5R30A.
    Last edited by pureZero; 06-25-2013 at 10:21 AM.

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    My S30 lessons have stalled recently also. I need something to break.


    Found a good reference on exhaust concepts, linked below. If you're tuning the exhaust system to generate pressure waves (think two-stroke engine pipes) at specific RPM ranges then a constriction can be useful. But just adding a random constriction to maintain velocity will just give random results. Why not go down to 2" or 1.5?

    Exhaust System Technology: Science and Implementation of High Performance Exhaust Systems


    On the shifter - there's a guy on Hybridz who came up with a very simple modification for the shifter bracket and rod on the Z32 transmission. A few cuts and welds and the lever is where it needs to be.

    The part is called a "support bracket" in the attached drawing.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    1976 280Z, with some minor modifications

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    Quote Originally Posted by Zed Head View Post
    My S30 lessons have stalled recently also. I need something to break.


    Found a good reference on exhaust concepts, linked below. If you're tuning the exhaust system to generate pressure waves (think two-stroke engine pipes) at specific RPM ranges then a constriction can be useful. But just adding a random constriction to maintain velocity will just give random results. Why not go down to 2" or 1.5?

    Exhaust System Technology: Science and Implementation of High Performance Exhaust Systems


    On the shifter - there's a guy on Hybridz who came up with a very simple modification for the shifter bracket and rod on the Z32 transmission. A few cuts and welds and the lever is where it needs to be.

    The part is called a "support bracket" in the attached drawing.
    If you'll go back in the thread a little bit, you'll see that I was mistaken about the stock Z32 exhaust tubing size in the first place. It is already 2.25", so I'm not down-sizing any time soon.

    Do you have any idea where that thread is, for the shifter modifications?

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    It's for an RB swap but the concept should work. You'll have to measure for your project. - Z32 Transmission Shifter Relocaters - Group Buys - HybridZ

    and the 240hoke part mentioned, for an L6 - Z32 Transmission Shifter Relocaters - Group Buys - HybridZ

    Use Google and search "site:hybridz.org z32 shifter" and you'll find a bunch of reading.
    1976 280Z, with some minor modifications

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    Quote Originally Posted by pureZero View Post
    I did, but seriously... I promise you that I am not blowing smoke here (no pun intended). Hot gases tend to move faster through the exhaust. Yes, exhaust will cool off as they move through the piping, but it needs to stay hot for a little while.

    And I'll stick to going with 2.25", thanks though. Just having mendrel bent tubing, no cats, and free-flowing headers will be a huge help to the engine. It's not that I'm trying to tell you that you're wrong, but I am going with what I know, and the link didn't really go into how to apply the information.
    Exhaust dynamics are much more complicated than "exhaust will cool off as they move through the piping, but it needs to stay hot for a little while." You seem to be designing your entire exhaust system based on a relatively trivial premise.

    Can't say I didn't try...
    2/74 260Z

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    Got my cutting pasting screwed up in Post #21. Here's the link to the modification -

    My cheap Z32/RB26 Tranny shifter Bracket. - Nissan RB Forum - HybridZ
    1976 280Z, with some minor modifications

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    Basically, guys... I know I'm no expert here. However, I have enough of an understanding on exhaust dynamics to make a set-up that will work okay. You need to remember one incredibly simple fact... I am on a very tight budget at the moment. Right now, I am more concerned with the car running well than I am about designing a high-performance exhaust. I simply don't have the kind of money needed to do so. I just want to make sure it will run well, and get decent power. If it sounds good, then great! There are exactly zero kits for the swap, and I'm flying by the seat of my pants a little bit. However, I am not going into this project blind, as some of your posts seem to be hinting at.

    The shop I'll go through to build the exhaust will be more than happy to take my ideas and help make them work, as they will have a better understanding of it all. And if I have to buy headers, instead of making my own, then that's fine. I will do what I have to do to make it work.
    Last edited by pureZero; 06-25-2013 at 03:12 PM.

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    Quote Originally Posted by Zed Head View Post
    Got my cutting pasting screwed up in Post #21. Here's the link to the modification -

    My cheap Z32/RB26 Tranny shifter Bracket. - Nissan RB Forum - HybridZ
    THANK YOU! That's exactly the kind of information I needed.

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    Just took about half of the sound deadening material out of the floor boards and tunnel... I'm finding that it isn't much easier to use dry ice than the heat gun I have. Either way, it isn't an enviable chore...

    There's a bit of cancer on the driver side floor pan, and I managed to see some daylight coming through the passenger rocker panel. Passenger floor pan seems to be fine though, just a little dented.

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