He's On Toroids

iTrader: (2)

He posted it on: 08-19-2009 https://www.rx7club.com/3rd-generation-specific-1993-2002-16/auto-tranny-saga-help-record-858339/

I'm not sure if he had the harness or not. In fact, looking back on some of his posts, I think he was running the stock ECU.

grimple1

iTrader: (1)

fair enough


I do think that a modified stall is probably the best solution in the long run; although, mine is on jack stands atm and amunoz is on a tear to get 600hp

amunoz3

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tsmysak1 broke how many autos at stock hp???? are u serious???? something sounds fishy.

Banzai-Racing

iTrader: (11)

I think if you look at that users post history he was having trans issues 4+ years ago and the car has been sitting.

I am not surprised that the stock trans can be used in excess of 400rwhp, it is basically the same unit used in the Cosmo with a 20B. Mazda could not have it blowing up every time someone decided to get on the throttle.

I am a little surprised that it has held up to nearly 500whp, and quite honestly I don't think it will handle 600whp. Even the manual trans has an issue with shreading gears at around 600. I am not saying it will not do it, and it will be interesting to find out what happens. I think you should install some sort of scatter shield just to be safe, if you haven't already.

At 488whp the car must have just been insane at shift points. We have customers with 330-350 and the cars spin the tires when shifting from 1st to 2nd

He's On Toroids

iTrader: (2)

Obviously he (tsmysak1) wasn't having transmission problems that were due to power levels. (100k plus transmissions fail, level 10 doesn't have the cleanest rep, the 30k may have had issues before it was installed)

The reason I included that post was for the information that seemed valid in it. The section after he says "here is what I have learned" where he goes on about the weak points in the transmission was interesting to me. Can anyone confirm these statements? Maybe by upgrading these parts amunoz can get to 600. (after he scatters the first one)

amunoz3

iTrader: (2)

the auto harness is the ****, its awsome...... good job.

He's On Toroids

iTrader: (2)

amunoz3: Any updates on your progress from the last month?

jeff p

I think the key here is the banzai racing auto harness. my transmission shifts just like stock and I thinks this is allowing the transmission to hit higher hp numbers without stress. before the harness many people reported transmission failure early in hp gains after adding a couple of mods giving the autos a bad name. I think this was stress related since the trans was not getting the proper signals needed to work properly. since the harness was created (thanks chris) there is no need to do a 5 speed swap I dont know why anyone would spend the time and money when that money could be used in so many areas to improve this great car.

Jeff

amunoz3

iTrader: (2)

good point jeff. If these cars stay with stock twins they never need a manual swap. even with me and my twin to4e crazy power setup the tranny is doing well....... Some performance shops that have built many auto cars said that i will be surprised on how much the autos can take. I think a lot of people here just have their mind set on just driving a manual sports car is the way to go. If people only really knew what the rx7 auto can do........ 3.90 gears is perfect for those high horsepower gains to

amunoz3

iTrader: (2)

The motor project starts on friday just been super busy.... and in the middle of all this professional photographers want to put my car in 5 different magazines. I didnt get to play a whole lot with 488 whp so i will start where i left off and go up from there. I will post all power gains at what times and how much i had gotten on it (which will probably be all the time lol).

grimple1

iTrader: (1)

I don't really have a problem with people swapping transmissions. That's fine and it's their ride.

What I have a problem is the notion that one MUST do so to enjoy an RX.

He's On Toroids

iTrader: (2)

I'm not trying to rush you, just interested in the project. How many miles did you get with 488?

weaklink

I agree 100% Jeff. When I was playing with the TCS I could see lockup, slip, and temp. They were not functioning correctly and the temps were very high. I agree that this probably leads to early trans failure. I have already swapped, but probably would not have had the Banzaii been available. Why was it so long in the making??? I think it's because the autos are predominantly the only "nice" rx7s left that haven't been totally thrashed, modded and hacked to bits. There's a market there now!

jeff p

the 4.33 gears are great for getting the power to the wheels on the stock twins and made the auto trans so much more fun. "it woke the car up".

jeff p

I am so glad chris explored this for us it was a big step forward in getting the auto's respected. Thanks again Chris


Jeff

amunoz3

iTrader: (2)

okay you guys i know i havent posted in awhile im still getting this tranny to work with the nasty half bridge idle of 2200 rpms lol. awaiting the return of my modified torque converter from level ten. it sucks that i was not fully able to test the tranny in a completely stock form.

He's On Toroids

iTrader: (2)

Yeah that's a shame. The rest of the tranny will remain unmodified though, right? What mods to the TC did you have done? what's the new stall?

amunoz3

iTrader: (2)

3k stall custom made from level ten to hold 500 whp. the rest of the tranny does remain to be unmodified.

a3dcadman

iTrader: (1)

I just did a total rebuild of my auto tranny, top to bottom, front to back and also put a shift kit in it. My clutches in the third gear pack looked like the waffles on an accordion at less than 1/16" thick. Other than a grayish ooze that permeated the oil everything else was okay. The valve body components werent moving freely and required a little coaxing to remove. It took me a couple of weeks to do the job, working on it a few hours a day, with most of the tiime being spent thoroughly cleaning all the parts and carefully re-installing all the new parts. With the dealer shop manual it was relatively easy and certainly wasnt as tough as I thought it would be. It works great with no problems and the way it shifts is definitely different.

I had planned on doing the conversion to 5 speed but this was a less expensive option for the time being coming in at about 5 bills with all materials, oil, supplies, and the rebuild kits. Fabricated my own special tools.

-chuck

He's On Toroids

iTrader: (2)

Impressive, how many miles were on it and why did you do the rebuild? did it fail or was it just shifting poorly?

ploplen

Cool, an auto thread! Nice to see some people that are satisfied with their auto trannies.

Someone talked about maintenance... What kind of maintenance do you guys do? I have only pulled the diagnostic codes

Maybe getting a bit of topic now, but how about driving style. I noticed that I made faster 0-100 kph (0-60 mph) in full auto mode rather than in hold mode. Maybe it was bad to rev it up to 7k? Any hints about how to use it in hold mode?

He's On Toroids

iTrader: (2)

Regarding the auto thread: Tell me about it, I almost think the autos are as persecuted around here as the V8 guys. We could use a sub-forum to get away from all the 'just swap it' guys.


As for maintenance, how many miles are on your car? They shouldn't require too much to maintain as long as you keep the fluids clean and the transmission cool. I am curious to see what the details are about that rebuild by a3dcadman, I wonder if that clutch pack wear is purely mileage related or if there was a failure that caused it.


Hold mode will allow you to rev it up to 7500 RPM. The problem is when you don't hit the button at the right time, and hit the rev limiter.

Hitting the Hold button as you pass 5500 usually gives you a pretty good timed shift (if stock). I tried playing with it on the strip and due to inexperience I had mixed results with the shifting. Sometimes I only got as good as without using it, sometimes a little better, but I could definitely tell on the sheets when I was late to shift and hit the limiter.

ploplen

47000km (about 29 000miles). The fluid is inside the gearbox and I don't have a temp gauge for the gearbox. I very rarely do any power braking.

Hmm.... Either JDM and USDM are very different or I have missed out on how to use it. I push the hold button so that the hold lamp illuminates. The gearbox is then locked into gear. L=1st gear, S=2nd gear, D=3rd gear. I then choose gear by pushing the gear lever up and down. I do not touch the hold button until I'm tired of doing the gear changing manually.

He's On Toroids

iTrader: (2)

I'd say keep up with your factory mandated fluid changes and you will have a happy transmission for a long time. I have approx. 95K miles on mine and it is still kicking. (90K miles were a fully stock car)


You can do it that way too. I personally don't know which way is faster or more repeatable .

I was leaving it in L with the Hold light on. When I wanted to shift I would hit the button again and it will up-shift. Doing it this way I cant accidentally push the stick too far if I am trying to shift vigorously. It also allows me to push the stick up into S and depress the hold button again while I am climbing through 2nd. That way I am ready for the button again when it comes time for 3rd.

I haven't gotten to the strip more then once and I don't have a G logger to tell you which way is quicker. So mark that down in the long list of items about the Auto transmission that have not been tested.

I've heard of all sorts of different ways of shifting that create better results. Supposedly if you are in D with the hold button on and shift to S you get a quicker downshift then just hitting the button in S. Both different ways of bringing you from 3rd to 2nd, but is there an appreciable difference?

a3dcadman

iTrader: (1)

[QUOTE=

As for maintenance, how many miles are on your car? They shouldn't require too much to maintain as long as you keep the fluids clean and the transmission cool. I am curious to see what the details are about that rebuild by a3dcadman, I wonder if that clutch pack wear is purely mileage related or if there was a failure that caused it.

[/QUOTE]

The clutch pack wear is attributable to a couple of things. 1. Its my understanding that because of the way the valve body is setup, there is excess pressure on that clutch pack. A shift kit is supposed to relieve that problem and I did install a shift kit. 2. I like to get on it and in full auto mode it shifts hard enough to spin the tires and cause the car to go sideways a bit. The stress of the shifts obviously took a toll on the clutches and plates only in one of the clutch packs, all the others were in fairly good shape.

The symptoms of imminent failure were characterized by a slight slipping between shifts which got progressively worse over time. When I pulled the valve body apart, many of the valves were so gummed up from the gray sludge that they probably were not working as they should.

During this break-in period, I used a less expensive ATF but will change it out to full synthetic at probably 500-700 miles. I will pull the oil pan and check out the residue buildup and also remove and clean the filter. I have a drain plug installed but I really need to see whats in the oil pan.

Any questions, feel free to ask and I will tell you what I can.

-chuck

FYI - These are Jatco transmissions and this particular model is also used in a couple of Nissans.