My dream come true, External transmission control

[jonseyq45]

Well, I have had an idea for some time about controlling the transmission.

I have read all the posts related to the transmission step down resistor. I have also looked at the device that a Subaru shop in Seattle is selling that opens the circuit based on engine vacuum. What I have done is prototyped a box with 2 Potentiometers and a vacuum control that is adjustable to when the second setting comes in. The idea is to raise the base line ohms from 12.8 to a higher number to tighten up the shifts without becoming too harsh. The second adjustments allow you to set the line pressure at higher throttle openings. I started with a proof of concept, then last night cobbled up a prototype. So far works as expected, no warning light and firmer shifts. What I want to have when I am completed is a box with two knobs and a vacuum line to replace the existing ballast resistor. Hook up the vacuum line, adjust the base line pressure, adjust the crossover, and then adjust the full throttle pressure.

I figured that there could be a market for this, but after thinking about all the help I have received from this group, I plan on giving the information and plans away for free. If you guys are interested in something like this, just let me know and I will follow up with the finished product.

Jonsey…..

[Infinitiguy19]

Do you think you can market these out, Like make them your self?

Do you have anything for softer shifts?

[jonseyq45]

For softer shifts, replace the current resistor with like 5 ohm. The ignition is already being retarded at the shift to lesson the hit.

Jonsey

[maxnix]

While I think this is innovative thinking, I wonder if it is a cure to a wear problem as I never have heard anyone complain about this on a new tranmission, and indeed, it isn't a problem on mine at 103K.

[qship96]

Nor mine at 224K.

[jonseyq45]

Maybe I did not describe it right. This is not for a wear problem. This is a performance upgrade. This firms up the shifts, no hang time. Feels like you have installed a shift kit. It also allows wot shifts with no slippage. After reading what people had said about the "slush box" and its shifting characteristics. I felt that I could go about it differently, with out going in the transmission. The other item I bring to the table is the adjust ability that a normal kit wouldn't have. Now for the last kicker, the total cash outlay will be around $30.00. I raced motocross for 20 years, had 4 stokes before it was fashionable. I built my own speed parts, and other custom internal engine parts. I like fast stuff that hangs together. Now I am an IT Operations manager who again likes fast stuff. I took from both sides to create this kit. I not trying to fix a problem with the transmission, even though slippage equals heat and wear, I am trying to improve the drivability and performance of the Q. Increase the giggle factor...........

Jonsey

[Infinitiguy19]

I am all in for this so basically $35 shipped for it?

Any chance you can make one and test it and report back?

I was wondering about the soft shifts, because it would be nice to have a button like the Maxima which has the options of stock, comfort and sport shifts, But it works differently.

[maxnix]

This firms up the shifts, no hang time. It also allows wot shifts with no slippage. After reading what people had said about the "slush box" and its shifting characteristics.

Remember those people are commenting on their used transmissions with who knows what kind of maintenance?

Few on this forum (maybe 10) even perform a mechanical exchange of the ATF fluid. Probably 40 run an auxilliary ATF cooler. Probably 2 change the later ATF external filter.

I for one do not experience slippage, and find the RE04R03A pretty responsive with the stock TCU. Remember the shifts were purposely softened by retarding the ingnition not only for comfort but transmission longevity. I think slippage is an indication of degree of wear, and hardening shifts may in fact accelerate this wear.

It would be most interesting if this were developed with a new Nissan remanufactured transmission for baseline purposes. I wonder if the need would still be perceived?

[jonseyq45]

I have built it and am in the process of testing it. When reading the posts from the more technical people here the expressed a concern that when the transmission does it mellow shift at higher throttle openings, what is happening is a built in slippage to soften the gear change. As we add power to our rides this actually works against us as slippage causes heat and wear (even if it is designed in) to the transmission. From reading some white papers on transmission design, I feel that increased line pressure and quicker more positive shifts actually improve the life of the transmission and lowers its operating temperature. I my self have installed a large B&M transmission cooler. The retarding of the ignition lessons the hit but not the speed of the shift and that's why I have designed the adjustability into the control kit. You set the the 2 different firmness of shift and when the the change from to the other happens. And addressing worn boxes, the added line pressure may help the box last a little longer. This is not a case of unplugging the stock resistor, this is using some controls to find another way of controlling it. I don't think Nissan settled on the 12.8 ohm resistance on the very first try. I think they looked at the customers requirements and then tailored it to that need. People often forget that our cars are designed to run on the worst gas available, at all different altitudes, with all ages and skill levels driving them. The whole car is a compromise to reach the widest group of people. What we do is tighten down those different spreads and refocus our performance, handling, and comfort using a much tighter set of performance criteria with factors already built into the car......

Jonsey

[qsiguy]

I've had my dropping resistor disconected completely for a while now. Always shifts firm. I messed around with a pot on the wire for a bit but it drew a higher current than the small pots can handle. What potentiometer did you use for the circuit? At times the current on the dropping resistor hits about 1 amp if I remember correctly. Typical pots handle only about 1/4 - 1/2 watt which is only about 2-4 mA @ 12 volts.

Sure the firmer shifts may be harder on the transmission but if I was worried about speeding up wear on anything on my car I would have left it stock and let my wife drive the kids to school in it. Some of us are looking for more performance even at the expense of comfort or excessive wear. This car is my toy so I'm going to play with it!

[jonseyq45]

The secret is to use a ceramic resistor rated at 10 watts or higher before the pot. I went through trying it with just the pot a few times before I thought I'll let the resistor take the hit with the heat and then fine tune it with the pot. Less resistance =less heat at the rheostat. Radio shack has a 10 watt 25 ohm one for $2.98. I matched it up with the stock ballast for the first setting and match it up with a 50 ohm one, again from radio shack ($1.99) for the second load setting The other item is use is from a Harley Davidson. The early electronic ignitions had a vacuum operated switch that changed between 2 curves depending on vacuum load. The thing that the Subaru guy sells up in Seattle for $52.00 is $14.00 at the HD dealer. You just have to drill out the epoxy covering over the adjuster screw.

Now you know my secrets

Jonsey

[Infinitiguy19]

Can you further elaborate how we would exactly hook all this up?

Any diagrams of some sort?

[texasoil]

I gotta have it PLEASE. Would greatly enhance 'track day' runs with the Porsche guys--no more s-l-o-w up/down shifts.

[3Q Jay]

Keith, i'm not so sure on the faster downshifts.

I have experimented extensively with 10+ watt ceramic resistors of varying ohmage. while it is certain that the upshifts are harder, even crisper in terms of lag time---the downshifts, particularly the 4-3 downshift is actually quite a bit slower, at least in my case. downshifts 4-3 faster either manually with gate, or under part throttle in 'D' with the stock resistor in place.

i do give jonsey props though for experimenting with this. although cost prohibitive for me, the $700 fully adjustable TCU would be the HOT ticket.

[Infinitiguy19]

if he can prove that this will not affect transmission life, and down and up shifts will be quicker then i am willing to test one.

[MinisterofDOOM]

Do you have anything for softer shifts?

You want SOFTER shifts?!?!!?!?!

[bullittandy]

if he can prove that this will not affect transmission life, and down and up shifts will be quicker then i am willing to test one.

I don't think someone would be so eager to get one of these to you that they would run durability tests-gotta gamble.

[Drake57]

...

I figured that there could be a market for this, but after thinking about all the help I have received from this group, I plan on giving the information and plans away for free. If you guys are interested in something like this, just let me know and I will follow up with the finished product.

Jonsey…..

Jonsey,

Good job. Many are intimidated by transmission and engine controllers, and doubtless the manufacturer put a lot of resources into developing the oem controllers, but if you are happy with the results, good for you and good for the rest of us.

Enthusiasts like yourself prove that it's not always necessary to accept what the manufacturers supply, and provide an alternative. No doubt you put considerable time and effort into it, and I thank you for that, and for offering to share.

PS I did add a B&M cooler and replaced the OEM transmission oil line filter with an external spin on filter so you may add that to your count Brian. If my automatic fails, I'm thinking 6 speed manual.

[maxnix]

I did add a B&M cooler and replaced the OEM transmission oil line filter with an external spin on filter so you may add that to your count Brian. If my automatic fails, I'm thinking 6 speed manual.

Good for you, Drake. Did you use the the Ford one? Does it filter to the same level as the OEM one? Think it is only a few microns, but can't recall. I wonder if the pressure relief valve is at the same setting? Was the one in the old filter tripped? Did you look at it internally?

I'll help you on the six speed. T66? You'll kick me out after 15 minutes any way. We need to meet up as I am not that far away (N of 620). Email me.

[Drake57]

Brian,

IIRC the oem had a bypass, I found a spin on that also had a bypass, I do not recall the number, it is a FRAM. I did cut the can off of the OEM filter, there was more or less a teaspoon of steel sand in the bottom of it but the paper was relatively clean.

The idea for a manual transmission is only a glimmer at this point, as long as the oem automatic functions.

[maxnix]

Still have that can? Might come see it as I need to do that now. Or at least get the Fram # and get a Wix or something.

6 speed manual is interesting if it will fit the tunnel.

[Jesda]

Its a fairly terrible transmission by modern standards. I'm glad folks are rigging up solutions to reduce wear and improve performance.

[MinisterofDOOM]

Its a fairly terrible transmission by modern standards. I'm glad folks are rigging up solutions to reduce wear and improve performance.

When I drive my dad's Maxima with the excellent 5 speed auto, then get back in the Q, I get very strong urges to rip the gearshift lever loose and beat the transmission to death with it. I can't believe it took Nissan that long to get it right.

It's especially irritating considering that the Q is superior to the (14 years newer) Maxima in every way except the stupid transmission.

I'd definitely be interested in this mod. Anything to improve those horrible mushy slow shifts until the details are worked out on the 5-speed conversion.

[maxnix]

Its a fairly terrible transmission by modern standards. I'm glad folks are rigging up solutions to reduce wear and improve performance.

Actually, it is a lot more heavy duty than it's succesor the RE05. Also, it outlives the BMW autos substantially if maintained, barely if not.

The best wear reduction solution is an auxiliary ATF cooler and frequent mechanical exchanges of ATF.

And the RE4 is much less expensive to replace than new 5 - 8 speeds which can run in excess of $6K for the transmission alone.

Recall that during Q45tech's documented turn with his second (Nissan new) transmission, the only decline in performance was .5 seconds longer shift interval at 173K.

I still think all these guys complaining about mush are describing a war problem. My transmission work amazingly well with crisp shifts. I think changing the TCU program woudlbe a more effective approach on one in new condition. Like JWT did.

[MinisterofDOOM]

No possible way it's a wear problem for me. My trans has under 30k miles on it, has been VERY well taken care of (had mechanical fluid flush a few weeks ago). It's just one of the concessions Infiniti had to make in order to not scare off too many wimps. A quick, strong shifting trans would scare away all the Lexus cross-shoppers.

[jonseyq45]

All,

Thanks for all the good feedback and its my pleasure to give something back to this community. I am working on the final settings now so you have a baseline to start from. I am also looking for a readily available box to put it all in, that would attach in the corner cut out in the fuse box near the battery. The other item I am working on is an adjustable kick down switch for the throttle. My GM allows me to move it up and down because the switch allows travel past the activation point. This would allow the transmission to kick down faster and at an earlier RPM. I also will hold the gear longer. Don't laugh, I did this to my wife's Pinto and it made lane changes a lot safer;) I will be working over the weekend and and should have some information and diagrams next week. I fully understand Maxnix's concerns and his thoughts on this. I am trying to come up with a solution that will not impact the reliability or have a very small impact on the transmission.

I have 165,000 miles on mine and I feel it represents what is out there. I have added the cooler, flushed and replaced the so called filter in the pan and changed to a quality ATF ( more on this later, I have another brain storm on the type of ATF to use). I take care of it as it may save my life sometime, oh that's my rifle....never mind. I like to tinker, I have a 6 cylinder Kawasaki that was a barn find. I am making it into a Streetfighter, I have adapted the coil pack out of a Buick GNX turbo. It now throws a spark across 15mm. I have also built a 6 into 1 header along with lightening the carb slides in the CV two barrels. It howls like a 12 cyl Ferrari. So you can see I am a tinkerer with a slightly different slant on things. Well I got to go and see in I can i increase the line pressure in my wife's dishwasher.......................

Jonsey
Modified by jonseyq45 at 10:53 AM 3/6/2009

[maxnix]

I bet that Straight 6 does wail. Always liked the original CB1000 six and even the Gold Wing flat 4 and sixes were smooth if a little heavy.

Good luck on your projects.

[qsiguy]

...I think changing the TCU program would be a more effective approach on one in new condition. Like JWT did.

I've tested a JWT TCU on my turbo and was unimpressed. I noticed no significant change good or bad. It felt exactly like my OEM TCU. Only benefit I could see from the one I tried would be if you were converting a 90-93 to first gear start. Had I forked over the large wad of cash JWT wants for it I would have been extremely upset.

I would like to get my hands on an adjustable one to test, maybe it would do something...

[MinisterofDOOM]

I've given thought to the JWT TCUs, but they're just too expensive.

Plus, the idea of having user-tunable line-pressure is really appealing. Mark out 2 or 3 settings on the pots and you can quickly switch to the most appropriate setting, from calm and collected for hauling passengers to firm and quick for having fun.

[jonseyq45]

Here is the story so far;

Have the stock resistor, added a 8 ohm on the negative side and then put the 0-25 potentiometer at the end. But first had my son who installed the large transmission cooler fix a leak at one of the connectors (teaching him about charge backs and warranty redo's) on the cooler. His comment was I think I know which one, mine was ggrrrrr...... When I roll back the resistance to 20.8 (stock plus first add on) I get a subtle difference, little sharper shifts, seems a little quicker to back shift. Now when I add the full 25 ohms to the existing load (always all or nothing) to the mix it start getting a lot sharper shifts with no harshness so far. It also seems to hold it longer in gear when accelerating. Kick down seems to be right there when you need it also. No lights on the warning panel, the car runs just like stock. I also noticed that first or second are right there when you need them at the lower speeds (I have a 94 TCU). Also the resistors are staying warm to cool so far. Before I burnt out a few pots before putting then on the negative side after the other resistors. I am looking for a little more range in the pot to see where the ceiling is for the aggressive setting. I also purchased the vacuum controlled switch from Harley Davidson Saturday. This with another adjustable ohm device will allow the wide open setting to be dialed in, at what engine demand and rpm and how firm the shifts will be (like unplugging the dropping resistor altogether) but with some control.

Well that's it , I will keep updating with the progress so far

Jonsey