Z31 VG30ET into an S30 project outline

[ZR8ED]

This is an attempt to document some of the major steps of performing a driveline swap from a Z31T into a 280z. It is not meant as a step by step manual. I have written this post after the fact. I completed this swap in 2000. Some of the pictures are from the original swap, and some are from the current setup that has received many upgrades, modifications, and asthetic work.

Please let me know if I have missed anything or some additional details should be added, as this will likely end up a sticky.

 

The donor vehicle was a 1986 300zxt. The recipient was a 1978 280Z.

Both vehicles were completely driveable at the time of the swap. For the initial swap, it was decided to use as much of the stock components as possible to make it easier to diagnose and troubleshoot getting the engine up and running again.

 

It took one day to pull the zxt motor/tranny and the harness, and I spent the next two weeks cleaning, painting, taking inventory, and removing unwanted gear...â€Who needs air and power steering?!†The old driveline was removed from my 280z and most of the wiring was removed, and the engine bay stripped and cleaned.

 

Trial fitting the placement of the vg30et was done as a complete unit with major accessories, and the 5spd transmission attached. This was done to determine placement, and clearance issues, as well as the shifter location. A low and setback position was a primary goal.

 

With the motor in the engine bay for measurements, there were some exciting developments as well as several challenges that were uncovered. First, the motor can sit completely behind the front crossmember, the hood will close, and the oil pan has plenty ground clearance.

 

The first thing to sort out is the tranny position and gear shift lever location. It can fit in the stock location and still have clearance for the engine in the bay, and a very nice setback position. The tranny mount on the transmission is very close to the stock 280 mounting tabs. I cut the stock 280 tranny mount, and offset it less than 1 inch, and welded it back up. I used this as the primary locater for pulling the motor in and out for trial fitting.

 

 

The stock hood latch needed to be removed, so hood pins were a simple solution.

The alternator bracket hits the frame so a new one was made. It needed to be relocated about an inch for clearance.

The stock oil filter does not clear the frame, so a different style was found. I used a filter for 90’s Toyota Celica.

Custom engine mounts were fabricated, as well as the frame strengthened to support the motor in its new location.

A major issue was that the stock turbo interfered with the steering. This required cutting the frame to allow room to mod the steering to get around the turbo. I Added another Ujoint that I picked up at a local race shop, and used a heim joint to secure the shaft to keep the second Ujoint from binding, and maintain smooth steering.

 

 

 

The engine/tranny assembly was removed several times to take measurements, and the stock top rad support was in the way, so it was removed to speed up install and removal. It was replaced after completion of the swap and it was tied into the rest of my roll cage for added strength. This was a real learning experience, I knew the top rad support was important, but did not know the extent till now. Even with an extensive roll cage already installed, the front end of the car still flexed when the car was on the hoist (no driveline). It flexed enough that when the car was on the hoist, the front rad support had room to spare on either side. When the car was on its wheels, the support could not be moved at all!!

 

 

I had a custom driveshaft made that uses replaceable ujoints.

I ordered a high pressure fuel pump and regulator, aeroquip fittings to handle the high pressure, various pipe, lots of plate steel and aluminum plating, tubular steel, etc...

The brake and clutch and fuel lines needed re routing as well, and this was easiest to do while the motor was out.

The throttle linkage needed to be setup. I simply took the whole pedal assembly and cable from the Z31 and put it in my Z!..it was pretty much that easy!

The speedo cable, and clutch slave were also pretty straight forward.

I had to have a custom SS rad pipe made. The 300zxt rads have the inlet and outlet on the same side of the car a S30 doesn’t.

 

 

All that was left after this, was to wire up the ecu, attach fuel lines clean up the car, take care of some oddball asthetic items, and start and move the car under its own power to make sure everything was tight, and that all clearances were maintained. After that, it was off to the exhaust shop for a custom exhaust. Lastly, I took it out for a cruise, and brought it back for a good once over to recheck every single item that was modified.

[ZR8ED]

This is the engine bay prepped for install trials. Note the front rad support is removed, as well as the stock L28 engine mounts.

 

 

This is the stock S30 tranny mount modified to relocate the Z31 5spd. This was done first to be able to have a fixed reference measurement point.

 

This is the Z31 5spd installed.

[ZR8ED]

Passenger side motor mount.

 

 

 

Driverside motor mount

 

 

 

Steering relocation, turbo clearance, and reinforced compression rod mount

 

[ZR8ED]

Custom alternator bracket for frame clearance.

 

 

 

Vg30ET positioning

 

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SS rad pipe

 

 

 

Engine bay as it looks 9 years later

 

[JSM]

Nice general write up.

 

I was curious if you left the trany mount in the stock position, not moved an inch, what would the outcome have been? Was this done to make the trany fit or just to move the engine back an inch?

 

If only to move the engine back an inch, would the hassle been less w/ mounting, drive shaft, etc. or did it HAVE to be moved to accommodate the trany?

 

Thanks

[ZR8ED]

The tranny mount was positioned this way to get the engine moved as far back as reasonable but the tranny was still too short to line up the shifter in through the hole in the tunnel and offer full range of movement.

 

I did modify the shifter lever slightly because it would touch the console slightly in 5th gear. I had it moved back about 1/2 inch.

 

moving the engine further back would have required more mods, and reworking brake lines etc along the firewall. It also leaves clearance for the crossover pipe, and leaves enough room to not cook the brake lines/firewall.

 

Scott.

[Comrade_Charlie]

is that as far back as you can make it? where is the shifter, is it as far back as it would be able to go without modifying the shifter hole?

 

reasons I ask is because im going to be using a pathfinder transmission(2wd)(pathfinder driveshafts are huge), which are very short(ill get a measurement of the shifter placement on it and a t5. and I was planning on a maxima intake with the TB in the front and the engine basically right on the firewall, going to mount the turbo in front of the engine. and Cant you just notch the frame rail for the alt?

 

How much of the Z31 harness did you take out? im trying to remove one at the moment and it seems that the only way to take out the engine harness is to cut it at some places, unless there is a easier way.

 

im going to run my l28et off of a z31 ecu with a z31 maf, and dist. its all the same basicly. so im going to go ahead and have the wiring done.

 

How does the power and torque in the s30 compared to a z31, because my z31 rolls out(a 8.89 in the 8th isnt bad for a mostly stockish 3200lbs car)

[Megatherion]

thanks for the info, I'll be trying to do the same swap in the next months

[ZR8ED]

Comrade_Charlie

 

Before the initial placement measurements, We had already had the drivelines side by side, and realized that there may be issues with the shifter placement,

 

Initial testing was to determine Shifter location, oilpan clearance, hood clearance, and firewall clearance.

 

With the engine fully dressed and with the accessories that would be used, we placed it in the engine bay, and managed to get the shifter up through the hole in the tranny tunnel. What we did notice was that the shifter hit the centre console when placing the tranny in 5th gear. I'm not entirely sure of the differences between the 240-280, but I am aware that they are slightly different in regards to the tunnel.

 

If I had removed the brake lines from the firewall, I could have pushed the motor further back, but I decided that it was already mid engine placed, and it was not worth the extra work. (It also makes working on the back of the engine possible.) With some work to the firewall and fittings on the engine, I could have moved the motor back another 1-1.5 inches. I think for long term, it is better in this position, as I have been able to replace the cross over pipe with the engine still in the car.

 

I removed all of the ecu harness from the z31. It took a lot of work to do it, but it does come out. I did not use all of the wiring, as my 280 doesn't support a lot of the electronics that a 300 has, and I eliminated most of the wiring that was not critical for the ecu to function. I was scrapping the car, and I don't recall specifics, but I was more concerned with getting what I needed off of the car, and I may have cut the car/parts to get at the wiring just to make it easier.

 

I could have notched the passenger side frame for the alternator, but it was easier to just make/mod a new bracket, and my frame rails were in excellent condition, and I didn't want to cut them just for the alternator.

 

As far as the feel of the new powerband, my last engine was practically a barely streetable race engine, and i can tell you that the vg30et was very smooth, with a very flat power band. I tested 4 differentials in one day. A 4.11, 3.9, 3.7 and a 3.54, and the car just got quicker as I transitioned from a 4.11 in order to the 3.54 I really needed to add "load" to the motor to get better performance. With the vg30et in stock form, it was only slightly quicker in the quarter. Once I modded it slightly, it was a different car since then.

So to sum it up, a turbo engine requires a totally different setup than a peaky high reving N/A.

 

With only minor mods to the suspension to correct the weight balance shift due to the setback position of the engine, the handling radically changed, and I found that I could dive deeper in to a turn, and the car "felt" like it pivoted around the corner. I couldn't feel the weight of nose of the car go around the corner. It was quite shocking, and I had to totally adjust my driving style to take advantage of the new handling characteristics.

[Comrade_Charlie]

What diff are you using? I have a 3.73open r200 Im going to be welding up(I have 4 turbo z31 halfshafts for it too). but the pathfinder trans has higher gears so I want to go with a 3.54

 

I have a arsenal of spare parts that im going to throw into my 280 eventuall the l28et I put in there isnt even running. it might not ever drive if I get money to put the VG in it. I love everything about these motors(EXCEPT the stock intake, if these came with the front tb maxima intake these engines would be perfect.

 

I want my engine smack dab on the firewall, have to pull it out to work on it or do anything, thats usually what I do any way. I dont want to cut the fire wall, might have to move brake lines(you say) to get it to work. Ill adress that when i get there. and ill be notching the frame rail, Id rather go that route.

 

but ill go get measurements. you using T5 or na trans, 71c?

[Comrade_Charlie]

26 1/2 inches from front of bell housing to shifter for pathfinder trans. 32inchs from front of bell housing to shifter on a 1987 z31 na 5spd trans. I am not going to be running a cross over pipe so i think ill be able to fit it far enough back.might just run no radio and have bent mustang style shifter haha.

 

Oh and on my friends wrecked z31 I think im going to cut up the front right of the car to get the harness out in one piece.

 

lot of good info on wiring a vg30 up here

 

http://www.z31performance.com/forum/viewtopic.php?f=6&t=6182

[ZR8ED]

I prefered the 3.54 diff, but it was an open diff. I now run a 87 LSD 3.7. I needed the traction.

 

 

I can snap a picture of the firewall placement, but I recall that the crossover pipe is one of the first parts to hit the firewall, and then it is a few of the waterlines under the intake plenum, then it is the plenum itself. (That is assuming you already moved the hood latch) I used a T5 from an 84 300zxt.

 

I will dig up some current links, to link some related information that may be usefull.

I will also add some current info about my car as it is today, with a dyno graph from my first tuning session.

 

Any suggestions, please PM me, and I will add it to the sticky.

[NCchris]

Excellent writeup! Question: If one were to front mount the turbo would the steering modification still be necessary?

tia

[Comrade_Charlie]

This is just a guess but. To front mount the turbo I don't think you would need to if you used 2 custom exhaust manifolds. But you might still have steering issues if you just used an extender pipe from the stock turbo manifold. Ive been thinking about using 2 nissan quest or 2 Pathfinder manifolds backwards for a front mount instead of doing fully custom manifolds.

[NCchris]

This is just a guess but. To front mount the turbo I don't think you would need to if you used 2 custom exhaust manifolds.

 

Yes, I was thinking custom manifolds with both coming forward and no crossover in the rear.

[HowlerMonkey]

If you front mount the turbo and get rid of the crossover pipe in the quest to move the engine back, you will also have to run a different plenum as the stock z31 plenum overhangs the crossover pipe.

 

Maybe a pathfinder plenum would work.

 

As far as trannies go, you might try the z32 tranny and leave the engine forward which should put the shifter exactly or a lot closer to where it should be.

 

The FS5r30 when pushed back might be larger than the tunnel.

[Comrade_Charlie]

If you front mount the turbo and get rid of the crossover pipe in the quest to move the engine back, you will also have to run a different plenum as the stock z31 plenum overhangs the crossover pipe.

 

Maybe a pathfinder plenum would work.

 

As far as trannies go, you might try the z32 tranny and leave the engine forward which should put the shifter exactly or a lot closer to where it should be.

 

The FS5r30 when pushed back might be larger than the tunnel.

 

If it doesnt fit Ill make it, lol. it is a huge transmission that why Im going to use it. Why do the swap if your going to throw a junk 5spd in there(I know the z32 one is the same) but the 71c and others just suck compared to a r30. The t5 isnt bad but I hear it doesnt hold a huge load of power, maybe it is better in a lighter chassis, you know, less load. If I do the swap I dont want drive line problems, pathfinder transmissions are easy to find so I figure if I get it to work good then If i brake one I can find another one for under 100 bucks compared to 300 from a z32.

 

I am just throwing ideas around as I still have the l28et in the car and it hasnt even ran yet, if it runs then ill drive it for a while untill I have everything for the swap, like money for a custom driveshaft, hx40 turbo, stuff to make mounts and custom manifolds, a engine(I have a vg30 sitting around but I want it to be a vg33 or bigger, if your going to go, go all out right? I already have a vg38 in the works, that might be done in a few months if I can get this maxima fixed and sold). It should be a hell of a car. VGsomethingET hx40 r30 transmission, welded r200, 4bolt z31 turbo halfshafts, nistune.

 

And I plan on running a maxima intake which has the TB on the front, it is my favorite, im trying to get my friend to sell me his 200sx vg30 intake, it is pretty small and is side mounted TB.

[260zturbo]

i came across this website http://xenonzcar.com/store/catalog/index.php?cPath=23&osCsid=40e61874a16631ecb6028e7d62580752 i plan to do vg swap in my z hopefully and i thought it would nice since it relocates the turbo upfront.

[ShaggyZ]

i came across this website http://xenonzcar.com/store/catalog/index.php?cPath=23&osCsid=40e61874a16631ecb6028e7d62580752 i plan to do vg swap in my z hopefully and i thought it would nice since it relocates the turbo upfront.

That's some expensive garbage!