Recipe for a powerful/reliable 2.8l turbo+tranny setup

[Guest Anonymous]

my mechanic has finally convinced me to stick with the 2.8 turbo motor and since i'll have a little bit of cash left over what can i do for/to the motor to get more out of it in terms of performance as well as reliability.

this motor will be going in my 72 240 with has an auto tranny also what can i do to my tranny since i'm tempted to keep the auto tranny set-up.should i just rebuild the tranny which i think is still stock or pull one off a maxima an reinforce it?

pls gurus let me know

[DAW]

I'm certainly not well informede on A/Ts but I think this is a good topic thread to update once in a while. There's a concurrent related post in "Drivetrain" re a member's quick L28ET with a 4N71B.

 

As to your situation, I know you'd be able to upgrade the 3N71B (Jatco) trans in your '72 by going to a 3N71B from an '81-'83 280ZXT as it has a higher stall speed torque convertor (and maybe beefier internals; anyone?).

 

There's a 3LN71B from the '81-'83ish Maxima that has a hydraulically-locking convertor that in itself is a step up from your non-locking convertor trans. When the convertor locks up, it's feels and drives like it shifted into a higher gear.

 

The '84 Maxima had an electrically-switched lock-up convertor 4sp A/T with the bellhousing you need to bolt onto your L28.

 

Then there were the A/Ts on the 300ZX(T)s which were 4spd A/Ts with electrically or hydraulically locking convertors; and the turbos have higher stall speeds than the na cars. The same Jatco trans is used in Starion/Conquests and some RX-7s.

 

It would be very helpful if anyone has some facts as to which applications offer the best/strongest internals (# of clutches,etc), as well as some stall speed comparisons, and if the Maxima L4N71B bell housing bolts onto all of these options for adapting to the L6.

 

Presently, I'm using a 3LN71B behind a 2.8L L6. The trans is from an LD28 and has a lower stall speed than even the na L6 (and much lower than the turbo applic.). It works great for the street but the engine is set up for a lot of low-end torque (83mm stroke) and I doubt it would work as well with less low-end torque.

 

Maybe admin could shift this to Drivetrain? ha

DAW

[fl327]

i would just have him dump a bone stock motor in, with exception of fmic, bigger fuel pump, adjustable regulator, and a bov, turn boost to 8-9psi, and run that 280zx stock auto with a good rebuild, dont make your mechanic do a whole buttload of custom work besides the actual swap, you will have too much fun with that setup.

[Lockjaw]

The maxima tranny can handle about 200 hp, beyond that you need the conquest one if you want overdrive. I would go with the ZXT auto, and a stock turbo engine with a good exhaust system, like a 3 inch mandrel with a straight thru muffler. You should be able to run 8 to 9 psi with that set-up.

 

You will need to do something with the stock pop off valve on the intake, and I would get a plug from the nissan dealer that goes into the intake manifold of a 300zx non turbo.

 

I think the stock turbo fuel pump will work at these boost levels and you won't need an intercooler if you run super unleaded, at least I didn't here where we have 93 octane. You can get a replacement pump, but if a 240Z the return line is not big enough to handle the flow of a larger than stock pump.

 

Get a boost gauge and a manual boost controller and don't go beyond 9 psi without octane boost or 110 leaded. Have fun with it and spank on some ricers.

[Guest Anonymous]

thanks all for the imput.i'm sure i've have all kinds of fun in this baby and kick a few RIcers while i'm at it.

cheers

[DAW]

An intercooler never hurts; it can only help. DAW

[DAW]

The Maxima 4N71B wouldn't be suitable for any performance application (but it would be an option for a retrofit upgrade on a stock 240-280Z with an A/T), but it is the source for the bellhousing to adapt the stronger 4N71Bs to the L6.

 

I'd like to know if anyone has facts as to which 4N71B is the strongest and why. I've heard it said that the Starion is a good donor but what about the 300ZXT and RX7, & Mazda 929? They have similar hp or higher curb wts so why wouldn't they be built similar? Are there other worthy sources like Mitsubishi trucks, Monteros? How does the A/T failure rate compare on all these sources? Anyone out there with good experience & knowledge that could do this comparison with other than heresay? I have a 4N71B from an '84 300ZXT that I plan to install in a '72 240Z but I'd reconsider if there's a better source at reasonable price/availability. Thanks in advance. DAW

[240Z Turbo]

internally the 4N71B's are from maxima, starion, 300zx are almost the same. The reason for using the tranny from a turbo model is the snap ring groove in the drum is located such that more clutches can be packed into the drum. Knowing this, you can use the maxima tranny and use the drums from a turbo model. Todd Wheeler sent me a drum from a 300zxt and it allowed me to use more clutches than the Conquest unit. Anyway, with valve body mods and OEM clutches, the tranny will handle 500hp easily in a light 240Z. I ran my tranny for 2 years with 400+hp.