L28ET Swap

[Pac_Man]

Hi everyone,

 

I recently picked up an L28ET with a T5 transmission. It's missing a few bits and pieces- water pump (cheap and easy), distributor cap (also cheap and easy), AFM, ECU, and harness. Of course I'll need a driveshaft and diff (or at least the driveshaft flange from it) as well. This will be going into a '76 280z.

 

I'm planning on having it be my summer project that I can work on in my free time. I want to tear it down and replace what needs it, then paint it, put it back together, and get it running.

 

Once the ball is rolling, I want to replace the J pipe with a FMIC. Planning on a modest same side in/out intercooler from CX Racing to make the intercooler piping easier and less complex. 24"X7"X3.5" core dimensions so it's a couple feet long, 7 inches tall, and 3.5 inches thick. Not very big but I feel like I don't need a lot with what I want out of the engine. My friend has done this swap in a '75 and his dad did his exhaust so hopefully I can commission him to help me out as well.

 

I've read that I can get away with using the stock harness by swapping the guts of the turbo AFM into the stock AFM but I'm a bit wary of this and I haven't been able to find much about it- I just saw it mentioned in a small thread on another site. If anyone has a link to a more in-depth discussion or write-up, that would be great.

 

Given the prices I've seen, I get the feeling it would make sense to go with a 300zx ECU/MAF upgrade from the outright. My reservation is that given my lack of experience, it may be safer to go with the stock setup and get it running before upgrading it. However, I'll be messing with wiring either way. Megasquirt is almost certainly above my head at this point.

 

The turbo has a bit of shaft play from just a quick wiggle test. I'll have to check it further once I pull it off and see if it will rub at all. If not, I'll probably just rebuild it and run it for the time being. I've read that the 280zx turbo manifold flange is uncommon. Will a different turbo require changing the flange, or is there one I can use without modifying it?

 

My horsepower goals are fairly modest in my opinion, at least for now. The stock rated 180bhp is fine until I start to upgrade things. I'd be happy with putting down 200 whp and right now I feel like anything over 250 whp would be excessive (and yes, the bhp and whp distinction was intentional). I'd like to avoid boost until ~3000-3500 rpm to keep it tame around town and cruising on the freeway. I know that is generally determined by the turbo and intake/exhaust setup but I'll need to read more about how to build it to keep it in that range.

 

Any advice and links are appreciated. Like I said, I've been doing a lot of reading but a lot of information is scattered and difficult to find. These are the areas that I'm uncertain about after the many hours of reading and searching I've done.

 

 

- Brandon

[cgsheen]

I'll never put a stock ECCS harness and engine management on an L28ET again.  I learned that lesson 3 or 4 times over now.

 

If you plan on pushing the engine past stock, don't even fiddle with the stock harness or a Z31 ECU.  Set it up with a tunable engine management system from the start (megasquirt, VG30e ECU with NIStune, or one of the many others.).  Otherwise you'll be going through that PAIN twice (at least twice - maybe more...)

 

What am I saying...  Even if you don't plan on pushing the engine past stock, don't fiddle with the stock harness.

 

You'd think that throwing on the stock harness and "getting it running first" would be the simple thing to do.  (I'll sit here and snicker while you do that... (with love, of course - because I've been there...))  You spend a large-to-huge amount of time doing that, then you'll spend it again when you decide to bag the stock crap and install something that works well.

 

Just my "Fatherly" advice - and I won't be offended, my kids rarely listen to me either (except in this regard - my youngest has already jetisoned the stock engine management on his '76 280 with L28ET and my oldest Son will have a completely custom engine management system on the L28ET he's putting in his '72 240.)

[seattlejester]

Unsolicited advice number two, find a drive shaft quick, or at least the input shaft (forward half of the driveshaft) for the transmission. Very difficult to find the input shaft for the nissan T5, and I haven't seen any replacements offered when I was on the hunt for an L28et swap.

 

^echo'd as above, the wiring for megasquirt is very manageable. I had the motor wired in I think 3 nights after work. I bought a stock harness for my 89 motor, and I used 3 wires from it as the plugs were cracking and quite a few of the wires were oxidizing green. I can only imagine a 81-83 motor would be that much more corroded/abused. 

 

Good luck, keep the thread updated!

Edited May 5, 2014 by seattlejester

[Pac_Man]

If you plan on pushing the engine past stock, don't even fiddle with the stock harness or a Z31 ECU.  Set it up with a tunable engine management system from the start (megasquirt, VG30e ECU with NIStune, or one of the many others.).  Otherwise you'll be going through that PAIN twice (at least twice - maybe more...)

 

Just my "Fatherly" advice - and I won't be offended, my kids rarely listen to me either (except in this regard - my youngest has already jetisoned the stock engine management on his '76 280 with L28ET and my oldest Son will have a completely custom engine management system on the L28ET he's putting in his '72 240.)

 

No worries, fatherly advice is what I'm here for. There's only so much reading I can do; advice from experience isn't something I can get just by reading about it.

 

I'm a bit confused, though. You said don't mess with a Z31 ECU and to go with Megasquirt or NIStune, but isn't a VG30e ECU a Z31 ECU? Or is there a separate one with NIStune? I've never really heard much about NIStune before and I've never heard it mentioned for this kind of application.

 

Unsolicited advice number two, find a drive shaft quick, or at least the input shaft for the transmission. Very difficult to find the input shaft for the nissan T5, and I haven't seen any replacements offered when I was on the hunt for an L28et swap.

 

^echo'd as above, the wiring for megasquirt is very manageable. I had the motor wired in I think 3 nights after work. I bought a stock harness for my 89 motor, and I used 3 wires from it as the plugs were cracking and quite a few of the wires were oxidizing green. I can only imagine a 81-83 motor would be that much more corroded/abused. 

 

Good luck, keep the thread updated!

 

Thanks! I'm definitely thinking of going MS or NIStune now.

 

I feel like finding the input shaft of the driveshaft would be more difficult than finding one by itself. Is it possible to locate just that part to have a driveshaft fabricated?

[seattlejester]

The Z31 ECU upgrade is a way to get a more advanced ECU into the vehicle as the standard ECCS or what not is not very intelligent. Not really much you can do with it, wire it up and it does it's own thing.

 

Nistune is a chip/mod service, offered from australia if memory serves, that basically allows you to modify parameters on the z31 ECU which makes it tunable. 

 

Regarding the driveshaft. I don't believe there are any replacement input shafts for that transmission. So you have to have an old drive shaft which you can take to a shop like Drivelines NW and they can make you a new shaft with serviceable joints from the back of the input shaft. My understanding was that the nissan T5 has a different splined output (either in spline count or diameter) then the common tremec T5's thus it makes it very difficult to connect the transmission to your differential without the factory one. You have a bit of time since you will need the exact measurement from the output to the differential flange, but the earlier you work on it the better.

Edited May 5, 2014 by seattlejester

[Pac_Man]

That's what I thought, my confusion just rested in the fact that cgsheen said don't bother with the Z31 ECU and then recommended a VG30 ECU. I'm assuming he meant don't bother with the S130 ECU though.

 

It will be a while before I even get this engine in the car so right now I'm just trying to figure out what my plan of attack will be for the engine management system.

[cgsheen]

The downfall of using a z31 ECU is plugging it into a stock L28ET harness.  And the temptation seems too great for most.  The ECU is a small part of the equation IMO.  Most of the grief you'll encounter will have nothing to do with the ECU and everything to do with the harness, wiring, connectors... 

[NewZed]

"VG30E" isn't really very specific.  For instance, Nissan went to sequential injection in 1990 for the 300ZX, which  would be a nice upgrade over batch or semi-batch.  I would think a 1990 to 1995 VG30E system might be the way to go.  Somewhere in the 90's I think the systems got extra complicated, maybe 96.  But pre-1990 might not be the way to go when there are tons of the early 90's VG30E cars out there.  Pathfinders and Maximas, for example.  

 

cgsheen has done the swaps though so would know better.

Edited May 6, 2014 by NewZed

[cgsheen]

exactly... It's not really the sequential injection I'm after, the '90's Nissan ECU's are just much better.

 

My main point on your swap is: Don't do the engine management twice and don't go through the pain of dealing with the stock ECCS harness and parts if you can avoid it. I'm not pushing a VG30 solution here - I'm pushing an "anything but stock" solution...

Edited May 6, 2014 by cgsheen

[Pac_Man]

I see what you meant now. It seems that if I were to use a Z32 ECU, there would be a lot more connector changes I'd have to make when wiring it. If I'm assuming correctly, I feel like I might as well go with MegaSquirt at that point.

[ryan95i4]

I'll just pile on at this point and also recommend avoiding anything in the 30yr old engine harness and archaic l-jet ecu. I went with Haltech, but cgsheen is right, build a new harness and use anything other than the orginal ECU and you will be much better off.

[cgsheen]

... build a new harness and use anything other than the orginal ECU ...

 

Those were the words I was looking for!

[Pac_Man]

In building a harness, I'm assuming I would want to buy new connectors. Is there somewhere I can do that or would I need to source the parts?

[ryan95i4]

In building a harness, I'm assuming I would want to buy new connectors. Is there somewhere I can do that or would I need to source the parts?

 

 

You can find bosch style connectors at amazon or any auto parts store for injectors and the factory CHTS.  

 

For everything else I used weatherpack connectors. You can get those on amazon, DIYautotune, waytek, etc.  There are other connector options out there, Deutsch for example, just depends on your needs.

Edited May 7, 2014 by ryan95i4

[Tony D]

For roughly $1,200 you get tuneable EMS, and harness. Nothing used Nissan save maybe sensors...

 

As above, some stuff just eats your time for no reward whatsoever.

 

I have not been impressed with the functionality of Nistune, and relying on old electronics (the newest Z32 Box you might get is what18, going quickly on 20 years old...about the time your modern electronics need "recapping"

 

Frankly, going with a similar-vintage GM system which is "Tunercat" compatible would be a better option simply from a local support standpoint. I was impressed with its user interface much more so than Nisstune.

[Pac_Man]

Thanks for the advice, everyone. I talked to my boss last night and he told me that one of the guys who used to work at our shop has done a lot of MegaSquirt work and will becoming back to work during the summer since he's at university right now, so I think with his help I'll be able to go the MegaSquirt route without having to worry too much.

 

My only question now is should I stick with the stock AFM with MegaSquirt, or is there an upgrade I can do like using a MAF instead? I'm also planning on doing the 240sx throttle body swap.

[m1ghtymaxXx]

Thanks for the advice, everyone. I talked to my boss last night and he told me that one of the guys who used to work at our shop has done a lot of MegaSquirt work and will becoming back to work during the summer since he's at university right now, so I think with his help I'll be able to go the MegaSquirt route without having to worry too much.

 

My only question now is should I stick with the stock AFM with MegaSquirt, or is there an upgrade I can do like using a MAF instead? I'm also planning on doing the 240sx throttle body swap.

 

 

I'm not well versed in Megasquirt, or any EMS for that matter, but the Megasquirt unit actually has a built in MAP sensor good to around 20 psi of boost IIRC. 

[ryan95i4]

Thanks for the advice, everyone. I talked to my boss last night and he told me that one of the guys who used to work at our shop has done a lot of MegaSquirt work and will becoming back to work during the summer since he's at university right now, so I think with his help I'll be able to go the MegaSquirt route without having to worry too much.

 

My only question now is should I stick with the stock AFM with MegaSquirt, or is there an upgrade I can do like using a MAF instead? I'm also planning on doing the 240sx throttle body swap.

 

 

You'll ditch the AFM entirely. Most people go to speed density tuning (MAP sensor) instead of using a MAF at all.

[Pac_Man]

I've been doing more reading up on MS (specifically about the MAP sensor) and feel at least a bit less overwhelmed by it now.

 

Now I know you guys will roll your eyes and shake your heads when I tell you this, but I got a good deal on the stock electronics from a running turbo car so I'm going to roll with that after the rebuild so I can make sure the engine starts and runs. I can't afford dropping the cash on MegaSquirt so I settled on this in the meantime. I'm still planning on upgrading to MegaSquirt in the future, though, so this should give me an easier starting point for familiarizing myself with wiring and the engine before I dive into something more daunting.

 

I also got the diff and driveshaft, so I pretty much have everything for the swap now.

[chaos]

You can shoot DIY a email they were very helpful with me on all was looking to do, priced it for me and made it very black and white. I've also been looking and stud ding the diagrams for ms3x, really not hard to follow and if you do run into issues the gentlemen that all have chimed in are very good at what they have done and always been helpful.