Automatic Trans for L6....

[BlueStag]

I was going to post this over on the "drivetrain" forum, but for some reason I am not being allowed to post there.

 

Which is OK, as my questions are specifically for the L6.

 

Two automatics were paired to L6's, to my knowledge: L3N71B was the three sp offered with Zs, and L4N71B was the same transmission but with an overdrive hung on it for 4sp offered on the Maxima.

 

These are Jatco transmissions and thus are made by Nissan, and so you should not be surprised to find many Nissan products using these and other Jatco transmissions.

 

Both of these transmissions are pretty old school hydraulic units.

 

The E4N71B was similar to the Maxima unit mentioned above, but heavier duty. It was run behind 300ZX's, and lots of V6 trucks.

 

I want to believe that the bell housing off the Maxima unit could be used on the heavier trans and still mounted to an L6.

 

Nisan also build a series of more modern 4sp autos that were much more electronic, using an ECU, etc.

 

I'm looking to chat with someone who can guide me to more information. I want to find something that will shift a little smarter and more aggressively, withstand the torque of a 28ET, and keep the fuel consumption under control.

 

Hell. Jatco even makes 5sp automatics......

 

In other words, how far up the food chain can I go while keeping the L6?

Edited May 31, 2012 by BlueStag

[letitsnow]

People have done GM th350 and 700r4 swaps behind these things, using the same adapters and the MS GPIO you could run a 4l60e or 4l80e if you wanted.

[HowlerMonkey]

The big question is whether the z31 turbo torque convertor fits the maxima L4n71b flexplate and bellhousing dimensions.

 

The stall is so low in the stock convertor that it really hurts performance.

 

If you want to build one to handle big hp, you could start with the Z31 turbo, holden V8, starion turbo, rx7 turbo II transmissions because they have the most clutch frictions and possibly gearsets with more planets.

 

The case of the trans. determines power level a certain bit by how many frictions it was machined for so you will find the maxima l4n71b case to not fit as many frictions as the turbo models.

 

That said, the L4n71b as used in the maxima uses an external line for lock-up while the E4n71b lacks this.

 

This case issue and the torque convertor/flexplate issues might make things more difficult.

 

L4n71b from maxima.

 

 

E4n71b....note the missing hydraulic line and addition of soleniods.

 

Edited May 31, 2012 by HowlerMonkey

[240Z Turbo]

4N71B mods

 

Get the maxima bell housing

I used a tranny from a starion because it held more clutches, but perhaps the 300zx unit would as well.

biggest problem is getting the proper converter built

 

Ran 11.2@129 with this tranny

[HowlerMonkey]

I ran a 11.5 with a 3n71b in a "j ported" mazda RX2.

 

It lasted many years shifting at 8500 rpms and it had a B&M shift kit in it but I had to spend 800 bucks (in 1982) to have TCI build a 4,000 rpm stall convertor.

 

That thing was a wild ride.

Edited June 9, 2012 by HowlerMonkey

[BlueStag]

I ran a 11.5 with a 3n71b in a "j ported" mazda RX2.

 

It lasted many years shifting at 8500 rpms and it had a B&M shift kit in it but I had to spend 800 bucks (in 1982) to have TCI build a 4,000 rpm stall convertor.

 

That thing was a wild ride.

 

I finally got the kick-down switch working at about 3/4 throttle. I like it!

 

The trans will go to 5000rpm before downshifting, which I need to believe is nearly the peak of the HP on my L26.

 

And the down shift is now happening really only when I want it. Yesterday it was kicking in at moments that I did not need it.

 

I'm suddenly liking this drivetrain a lot more.

[Tony D]

May want to PM Bernard as he is running the 3N71 Turbo Tranny on his ZX, far as I remember. Manual Valve Body.

JeffP was playing with the Nisstune to control the Z32 Autobox behind his Turbo Engine in his 79 Coupe Drag Car.

[BlueStag]

May want to PM Bernard as he is running the 3N71 Turbo Tranny on his ZX, far as I remember. Manual Valve Body.

JeffP was playing with the Nisstune to control the Z32 Autobox behind his Turbo Engine in his 79 Coupe Drag Car.

 

I think I will be leaving well enough alone for now. Remembering that this is my only car..... But I'd really like to give you a 0 to 60 run, I expect it will be obviously faster than the last time you rode in it.

[Tony D]

hehehe!

 

"It Begins"

 

The "Blue Turd" you saw me driving around in is basically my only car as well. In order for me to pursue similar endeavors, I've figured I'm going to get a BMW E36 to drive daily when in town so when I'm there in the states, I can start an involved mechanical project and if something comes up....I CAN LET IT SIT FOR THREE MONTHS till I return and have the time to properly address it and not simply rush to cobble it together because I got to get to work on Monday.

 

I know your pain, man! I know your pain!

 

I did happen to uncover an Autobox next to the grey container under the weeds. I'll look into it to see where it came from... I gave the last two away for $75---one N/A and one from a great running 83 L28ET that I was doing rally jumps through my wash in the back yard before I cut it up and took the driveline to use! No plans to do that with my 4N71's but who knows....

[BlueStag]

hehehe!

 

No plans to do that with my 4N71's but who knows....

 

Well, remember, I do have a 4sp just now, so I would need a REALLY good reason to put something else in there. It has an untuned L26 in front of it, so I don't think it is suffering. Including the fact that it is in a car no heavier than Nissan sent it out in.

 

Hey, what sort of numbers do people get out of N/A fuel injected L28s? Can I get over 150 hp at the flywheel and still have an environmentally friendly engine?

 

Without spending buckets and buckets of money. It seems to me the envior question rather limits the choices of cams, but a good ecu swap might serve the purpose rather well.

 

The point being that this thing just STINKS of gas!

[letitsnow]

My somewhat stock L28ET made 270rwhp, that's what that stag really wants.

 

150 fwhp is less than the L28e made stock, isn't it?

[BlueStag]

My somewhat stock L28ET made 270rwhp, that's what that stag really wants.

 

150 fwhp is less than the L28e made stock, isn't it?

 

270hp? I'd be dead within the week.

 

I'm trying to remember what the claimed HP of the stock L28 was. I don't believe claimed numbers readily.

 

If I could have a clean burning 160-175 hp without stressing the engine (I know, I know) I could get real interested.

[Leon]

My somewhat stock L28ET made 270rwhp, that's what that stag really wants.

 

150 fwhp is less than the L28e made stock, isn't it?

The L28e made exactly 0 fwhp.

 

Now if you're talking bhp, then It was rated around 140-170 bhp, depending on what standard you're talking about.

[letitsnow]

You're talking flywheel hp, right? There's a big difference, my 270 at the rear wheels is approximately 310-320 flywheel.

 

I don't honestly know much about N/A L's, but I don't think your goals would be very difficult, I've seen a bunch of dyno plots posted with numbers like that. Wiki has some info on stock ratings. http://en.wikipedia.org/wiki/Nissan_L_engine

 

If your carb'd l26 stinks badly of gas, you may have a leak or need to spend some time tuning them. The couple of carb'd Z's I've been around never smelled much. The L26 wasn't rated much differently than the L28 power wise.

 

Edit: by fwhp, I meant FlyWheel HP.

Edited June 12, 2012 by letitsnow

[Tony D]

"my 270 at the rear wheels is approximately 310-320 flywheel"

No, it's NOT!

It's 270 at the rear wheels. PERIOD.

Unless you were on a very specific chassis dyno which has been calibrated to the SAE requirements, a RWHP number is THAT and NOTHING else!

To B-Stag, 170HP drop-in is a smog-legal stock L28ET with a boost controller. And you can tweak that to 200 without drawing the ire of the Smog Nazis every 2 years (or from random roadside testing...)

[BlueStag]

]To B-Stag, 170HP drop-in is a smog-legal stock L28ET with a boost controller. And you can tweak that to 200 without drawing the ire of the Smog Nazis every 2 years (or from random roadside testing...)[/color][/size]

 

My chassis is a '73 (in California) and thus is exempt from smog testing.

 

My conscience, however, is not. If this were just a hobby car that I was driving a few hundred or thousand miles per year, I certainly would not be considering a FI engine. I expressly chose a Datsun L6 due to the fact that it can be readily fitted with SUs.

 

 

If I ever do go to the expense (no time soon) and the trouble of swapping in a more powerful engine, I will be choosing either of the ZX L28 na or turbo. Which one will be a matter of opportunity, cost, complexity, suitability to the vehicle, implications for complications (need to swap in an R200? Need to find a burlier 4sp automatic? More cost.)

 

The fact is that Stags have been built with 400hp engines. But I don't like to think what the necessary upgrades of the suspension and brakes are driven by that. Certainly anyone who takes a Z past 250hp is advised to consider these elements.

 

The Stag is, in fact, very similar to the ZX. Both have semi-trailing arm rear suspension, similar size and weight, wheelbase and track. I think the ZX's brakes were slightly superior in stock form.

 

I am certainly not looking for an absolute pavement beater. 200hp would certainly get my 2700lbs car moving at a remarkable rate. Just getting the down shift worked out such that the trans takes the 125hp engine to the rpm band where I actually get that sort of hp that makes the car a pleasure to drive. I really need a manual transmission in some sort of sports car, long time since I have shifted.....

Edited June 13, 2012 by BlueStag

[Leon]

You're talking flywheel hp, right? There's a big difference, my 270 at the rear wheels is approximately 310-320 flywheel.

 

I don't honestly know much about N/A L's, but I don't think your goals would be very difficult, I've seen a bunch of dyno plots posted with numbers like that. Wiki has some info on stock ratings. http://en.wikipedia.org/wiki/Nissan_L_engine

 

If your carb'd l26 stinks badly of gas, you may have a leak or need to spend some time tuning them. The couple of carb'd Z's I've been around never smelled much. The L26 wasn't rated much differently than the L28 power wise.

 

Edit: by fwhp, I meant FlyWheel HP.

The acronym FWHP is typically used to describe "front-wheel horsepower". BHP, or "brake horsepower", is the term used to describe power measured at the flywheel. It is called so, because of the use of a brake to measure power at the engine's flywheel on an engine dyno. Semantics...

 

Again, the L28E was rated at something like 140-170 BHP, depending on what standard is being used to quantify that power.

Edited June 13, 2012 by Leon

[letitsnow]

Front wheel drive is for the feeble, I don't really deal in FWD cars and my acronym usage mirrors that. I will adopt BHP to mean power at the crankshaft though, less ambiguity I suppose.

 

Tony, I was simply trying to make the point that BHP and RWHP can differ, sometimes significantly, not to give accurate relationships. 180 RWHP is quite a bit different than 180 BHP.

[BlueStag]

Front wheel drive is for the feeble,

 

Try a well sorted Lancia Fulvia and perhaps you will see things differently.

 

I'd kill for a Fulvia.

[Tony D]

Standard Glossary of Terms and Definitions is in the front of every engineering paper so this kind of made-up terminology doesn't happen.

There are standards for terminology. AS are there for Dyno tests!

 

My point was that a RWHP number is NOTHING more than that, there is NO WAY to 'estimate' the flywheel horsepower UNLESS the chassis dyno you have is very specially calibrated according to engineering standards regarding the relationship between what you measure at the wheels and what would be produced under an SAE J-Spec'd Dynamometer running an SAE J-Spec'd BHP Test. And if this is the case, chances are it reads out in BHP and states the SAE J-Spec that the testing conforms to.... Without reference to the conforming SAE Spec used when running the dyno test...it's an advertising, salesman's number worth nothing more than the integrity of the guy boasting about it. Give me one with an SAE J-Spec and I'll pay attention to it.

 

Because numbers can differ, doesn't mean they will. When you are fast and loose with Dyno numbers throwing in 'correction factors' and 'estimates' they become ABSOLUTELY USELESS.

 

The change in the L28E HP reflects refining of the ENGINE DYNO TEST PROCEDURE AND SPECIFICATIONS---nothing more! It remained practically the same to the rear wheels when it was rated at 170 BHP as when it was rated at 142. A chassis dyno, on the other hand, running say---eddy current, would have shown the same range of 89-103Kw (120-140 HP---the normal range you see with stock L28's) to the rear wheels. Engine dyno numbers are USELESS without knowing what spec they were performed under. Saying "170 BHP" means absolutely nothing. Saying "170 BHP per SAE 179J Specification" means that there is a way to TRACE THE FORMULATION OF THAT NUMBER. IT can be REPLICATED. I think Ford learned a little bit about this a couple of years back when salesmen and marketing got some people PPO over HP Claims that were virtually unsupportable.

 

What is more true to say is that generally there is very little correlation to BHP and performance, whereas RWHP generally is correlated directly with many aspects of performance evaluation.

 

Newer Engine Horsepower Test Specifications are more and more 'true' to giving you an Horsepower Number you can relate to actual corresponding performance. The more they refine the specification, the closer that number comes to being directly reflected in a chassis dyno test.

 

Many have gotten upset that my L28E spun a RWHP number of 147 "That's higher than the factory had it at the Flywheel"---maybe true, but production variance and proper tuning can make SIZEABLE differences in what you will see on EITHER an Engine or Chassis Dyno. What it's "Rated" at is for a production engine, with production tolerances, put together on a production line. That can change spectacularly on older engines like this with proper assembly and fitting of the exact same components.

 

As for FWD being weak...wellll it DOES have the advantage usually having less driveline losses. So unless you're driving a VW Beetle or P-Car, chances are the exact same engine, running through a RWD setup, and a FWD setup...well, the RWD would be the one that show up as "weak"!

Edited June 14, 2012 by Tony D