2JZ in a Z4 Coupe - Custom Project

[dre99gsx]

After doing some measurements and making a few calls, turns out cutting my driveshaft won't be an option. I need it shortened by at least 10mm, which is almost nothing. I found a Z3 driveshaft which is identical in every way, but 6" too short. Could not find any other BMW driveshaft that would work based on research.

Called up DSS and got a quote for a custom one-piece drive shaft (roughly $1k). Had a choice: Pay $1k, be done with it, or cut the subframe, move the motor up ~15mm, and use my current drive shaft for $0. I chose to cut the subframe. Mostly because I need to weed out issues and get this driving before spending the big $. Going for low-budget right now.

My favorite tools


Before:


The oil pan current has about 3mm clearance to the crossmember front and above.



Cut:



Adjusted motor/trans mounts to move engine 13mm forward, still have clearance under subframe and can now mount stock driveshaft with ease! Waiting for some 304 SS sheet to weld up the subframe holes.

[dre99gsx]

Draining massive amount of oil


This is why you should always inspect any motor you buy. Found a broken oil cap sitting between the intake manifold runner near the fuel rail. Thought to myself... "wonder where the broken pieces went?".


Look closely at the oil drain hole between the cam lobes Good thing I went digging before I trying to rotate the assembly (to remove the Torque converter bolts on the other side).


Child Labor





My exhaust side block mount was hitting the turbo hot side


Trim here, cut there...


Fits. I'll be creating a steel heat shield to help protect the aluminum mount from melting. Should be less of an issue when I go tubular headers in the future.




After further inspection and realizing this motor had quite a bit of sludge, I decided I'll be tearing it down COMPLETELY (minus pistons/rods/crank) and doing a full cleaning and refreshing - gaskets, ARP head bolts, etc. Might as well do my best here so I don't have to pull the motor again.

[AmmarYasirA]

This is going to be so sick. Excited to see how this plays out.

[dre99gsx]

Disassembly - crud on the head cam caps



Lots of carbon deposits on valves, head bowls and piston tops



Cleaned most of it up


Checking for flatness with a precision straight edge



Washed the block, ready for assembly


Engine seems healthy without going into further measurements for bottom end. Valve stems looked clean and dry, don't think valve seals will need to be replaced. Ordered a bunch of o-rings and gaskets, using an old oil pump/water pump I have from a previous build, new headgasket, ARP studs, and buttoning her back up. Keeping it simple and budget for now.

[dre99gsx]

Ran into a roadblock today:

Aristo 2JZ throttle body is drive-by-wire (not cable controlled)
Z4 throttle pedal is electronic

All is good, except the Z4 pedal voltage values are not correct with respect to what the 2JZ ecu wants to see, and controlling the 2J throttle body isn't cake.

I can go to a cable throttle body from the US MKIV, but after looking around, can't find anything that will fit the Z4 for cable operation.

If any of you know of a gas pedal which can be swapped with cable control, let me know!

[E86Z]

Just a thought. Are the pre facelift (m54) convertibles by cable?

[NickyC]

Good
Freaking
Grief

:O

[dre99gsx]

Replacing automatic brake pedal with manual brake and clutch



Clutch uses the same brake master cyl reservoir



Tried to find a way to convert to a drive-by-cable pedal system, but there is no room for one under there. Even tried to fit a E30 and E36 gas pedal to no avail. I'll end up controlling the Z4 3.0si DBW throttlebody with my standalone.


Powered up the 2JZ ecu to test the DBW Aristo throttle body using the Z4 pedal. Voltage ranges of the Z4 pedal don't match the ranges expected by the 2J ecu, thus it won't work.




New 2J oil cooler seals


Cleaned the oil cooler of the ugly gooky mess from supposed overdue oil changes from this motor


ARP head stud washers - older kits used smaller diameter washers which would dig into the 2J head. This kit has the correct washers. Black = ARP Gray = OEM 2J





Was planning on using the oem 2J intake manifold - not only is the Z4 throttle body larger in diameter, but this would awkward custom mounting



Headgasket, seals, parts


More child labor. I keep finding kids on the street to help turn a bolt





2J VVTi crank pulley - 36 - 2

[dre99gsx]

Continued engine assembly




240 ft lbs!!!






Purchased a cheapo-Fleebay manifold, checking fitment. Way to many problems with these Chinese manifolds. This one will end up as a paper weight.





Transfering over N52 alternator and AC Compressor

[dre99gsx]

Mocking up AC Compressor on the passenger side (opposite of 2JZ original design)


Completed brackets, painting later...




Mocking up Alternator - this will need some extra work since I wont be using a hydrolic steering pump (Z4 has electric assist steering). I ordered an extra idler pulley to space the belt out

[Daemonblitz]

Progress ! Awesome !

[Taskmaster]

Awesome!!

[dre99gsx]

Checking clearances - like it was made to fit



Collins plate clearance to rear water pipe on the 2J. Was able to unbolt the pipe from the block and shift it up a bit. Just clears..







Waiting on a real manifold, mocking up with Fleebay for now. Can't clock the turbo correctly with this manifold anyway - garbage.

[Finnegan]

Dedication and skill. Wonderful.

Subscribed.

[Vanne]

Sweetness... popcorn at the ready . Tuned in Toyota/bimmer hybrid action

[NickyC]

My favorite car of all time, with my favorite engine of all time (which I've owned hah). Incredible!

[dre99gsx]

Suprastore.com manifold finally came in, work of art!


Checking fitment. A+. Enough room to clock the turbo, oil drain points straight down with no interference.




Ebay intake manifold mockup. Unfortunately, it points my throttle body into a dead corner.


No way to route 3" intercooler tubing through here...


This is the angle I need:


Checking fitment of a E46 Mishimoto radiator, Check.


Hacking up the Ebay manifold


Tack welded the proper angle. Will finish this up next time...


Also measured and ordered an 18" x 3.5" frontmount core, and some end tanks to weld up next week. Progress...

[inTgr8r]

Epic!

[dre99gsx]

Research: Fuel pump and Fuel filter are inside the tank. Can only get to them from under the vehicle, need to remove exhaust and bunch of shields, need to empty tank as much as possible. Actually have to reach into the tank to fish out the pump it seems. No idea how easy it is to update those pumps. Was going to go dual Walbro and bypass the entire internal fuel filter assy, do a -6an line and standard fuel system. TBD

Also, unlike the Supras where you supply a TTL signal for low or high fuel pump voltage, the Z4 has a fuel pump controller (ECU) which regulates fuel pump voltage via CAN messages. Yikes. I can bypass it all and control the fuel pump via a relay, but from some reading:

"
The EKP control unit controls the EKP according to the system mode of the fuel supply system in the operation of the vehicle. The fuel output rate of the EKP is activated and regulated according to a given characteristic curve via engine speed recognition. The reference variables for this are the fuel requirement of the engine and the fuel circuit systems.

Emergency operation

If there is no communication with the DME (engine ECU) of this is defective, the EKP (Fuel Pump) control unit switches to emergency operation. The electric fuel pump is fully activated."

If this is correct and pump runs at full voltage, then I can just regulate it with a FPR up front.

[Jumbosock]

Cool build. I enjoy the updates. But how do you get all the energy/motivation to do all this stuff? Maybe I'm lazy or hypothyroid.

[NickyC]

I'm not sure if you'd want to divulge this information, but not counting all your labor, what kind of dollar amount do you expect for this swap (not including the car itself)? Obviously the labor involved could probably double the cost of the parts alone, but I'm curious to know.

[dre99gsx]

Being that most parts are used or recondition, and also spare parts I had laying around from my Supra (past builds and rebuilds), the cost in parts is fairly low for me so far - not including any cosmetics like wheels/suspension/lips.

As for resale, I haven't even wrapped my head around that, but as with anything, money talks! In the end, I'm leaving enough wiggle room to quickly swap back to 100% stock in case I do need to sell quickly. Or, sell the project as is for anyone who wants to take on the challenge.

The hard part is done - fitting it in there. It fits. Now is just tying up loose ends, wiring, tuning the motor and "coding" the BMW electronics.

Perhaps I'll beat Toyota/BMW at their game to the supposed "Z5/New Supra"