T50 to AZ6... a "new" option for gearbox issues
|
01-29-2007, 11:49 PM
Post: #1
|
|||
|
|||
T50 to AZ6... a "new" option for gearbox issues
A brief overview... the AE86 GTS is going on 20 years old. It is rear wheel drive. It was originally equipped with the 4AGE twin cam 4 cylinder, a 5 speed transmission, and a solid rear axle. In recent years the AE86 has garnered "collectors status" as well as becoming a cult "drifter". The AE86's popularity is VERY strong!
The 5 speed transmission is known as the T50. The 5 speed T50 evolved from the earlier T40 4 speed. The T40/T50 was originally designed for engines producing 40 to 100 hp. The stock power of the AE86 4AGE is 112 horsepower. The T50 in stock form tends to have 2nd gear difficulties as it has aged. Cost to rebuild a STOCK T50 (complete rebuild) are quite expensive, parts can cost $900+ and the labor would add another $450. There are TRD performance gearsets for the T50, they would add somewhere between $1200 and $1900 to the rebuild cost. The TRD gear set is more substantial but overall the T50 remains fragile. Besides its fragility, the stock gearing is VERY poor. So poor that when it was originally tested by Road & Track in February 1985, they commented, Quote:The GT-S was a fraction slower... ...there were times and places when the engines power couldn't be used... ...the jump from 2nd to 3rd is too wide and the jump from 4th to 5th isn't wide enoughadding a TRD gear set improves the gear spacing, but because the TRD gear set's 1st is so much tighter (2.6 or 2.3 to 1 as opposed to 3.5 to 1) it makes use on the street MUCH tougher. Move ahead in time 15 years... The Miata is introduced with the AZ6 6 speed transmission. In essences the AZ6 is a close ratio 5 speed(gears 2 through 6), with a taller 1st gear. This in essence gives you the advantage of a close ratio transmission WITHOUT sacrificing the ease of use that a tall 1st gear offers. The AZ6 was originally designed for the Altezza, the Miata and the RX8, its power capability is well over 250 horsepower. The AZ6 is capable of running just about ANY type 4AG - n/a, s/c, turbo. The gearing is just about perfect for the 4AGE AE86 - placing redline shifts at or above 4500 rpm(TVIS engagement) for each successive gear The problems to overcome: 1) Toyota gearbox is a self contained unit, the bell housing isn't intregal to sealing the gearbox itself, the Miata bell housing is also the front of the gear box case. This is the biggest problem to overcome. Doing research I've found that this isn't an unknown swap (AZ6 into AE86) but it is VERY RARE, but it has been done a handfull of times, but in all previous cases the Toyota bell was welded to the AZ6 bell and a clutch mixture has been used. The problem with this is the engineering involved with the clutch working range was never taken into consideration. The reliability of this is unknown. "We"* decided that the most reliable way to do this was to use the entire Toyota clutch... complete bellhousing, hydralics, disc and pressure plate, all Toyotas engineering. To do this we needed to cast an adapter. This adapter would closee up the AZ6 gear box, support the output shaft bearing, and have a flange to bolt on the Toyota bell housing. 2) Since we decided to use an adapter, the input shaft becomes too short. Also, to use the Toyota clutch, the splines are wrong anyway. The Toyota input shaft will be grafted on to the Miata input shaft. this will extend the length needed, and fit the Toyota clutch 3) The AZ6 is physically larger than the T50, a bit wider(no so wide to be a concern) and quite a bit longer. The length on the AZ6 will be compensated by shortening the stock 2 piece drive shaft. The front section will be shortened and the AZ6 output shaft will be added. This will keep the driveshaft support bearing in the stock place, thus keeping the driveshaft to axle angles all intact from the stock driveline. 4) As stated above the AZ6 is larger, one of the issues in this swap is the shifter would come through the floor in the AE86 about 9" behind where it does originally. Now if this was a racing example, this would not be an issue, just move the parking brake and cut a hole, BUT I don't want to do that, so the shifter section is going to be shortened so the shifter will come through the floor in the correct location. This will require shortening the top of the AZ6 case and shortening all the shift linkage. 5) The AZ6 as fitted to the Miata does NOT have a rear transmount as is conventionally known... the AZ6 in the Miata has a link to the rear this link holds up the back of the AZ6. This link section needs to be modified to hold a conventional cross type transmission mount. 6) The last problem to overcome is speedometer drive. The Miata uses a digital signal, the AE86 uses a mechanical cable. For now... we are looking at fitting a mechanical drive to the AZ6. Now.... there are a lot of VERY intricate details that seem to be "over engineered" for a one of a kind swap. Now some of this is because I want a fully useable car when I'm done, but there is a second larger over riding purpose... go back... look above.... T50 remains fragile AND The AZ6 is capable of running just about ANY type 4AG - n/a, s/c, turbo. soooo..... Rob and I decided that most of the T50s are now junk, and for nearly the same cost as a rebuilt T50 with a TRD gear set you can have an AZ6! The final costs will be set once the engineering is done, but as of now the total cost for a complete AE86 AZ6 swap would come in UNDER $3000 That might seem like a lot, but once you compare it to rebuilding an inferior trans...(or purchasing a Quaife for $6g!) it makes PERFECT sense! * - "We" are Rob Golden owner of Pineapple Racing http://www.pineappleracing.com/ - renown Mazda builder.... and me Why.... bet that is running through some brains.... simple really... T50 sucks. W box is fine... but could used better ratios... AND one more gear(for use with a 4AGE). In essence(for 4AGE use) look at the AZ6 as a 6 speed W box..... But why?.... well, the one part of the puzzle that isn't there... is the addition (in my case) of a 4.10 Richmond Racing rear diff. The slightly taller 1st gear of the AZ6, matched to the 4.10 offers me nearly identical starts.... as the T50 and the 4.30... and between the 4.10 and the .843 6th gear I should lower high rpm by over 700... which I'm expecting a 10% boost in mileage... Ratios for those that want them....... Original Transmission T50 gear ratio 1st 3.587 2nd 2.022 3rd 1.384 4th 1.000 5th 0.861 Final Gear Ratio 4.300 TRD set#1 For T50 1st 2.630 2nd 1.891 3rd 1.384 4th 1.000 5th 0.861 TRD set#2 For T50 1st 2.341 2nd 1.607 3rd 1.195 4th 1.000 5th 0.886 AZ6 from 1999-05 MX5 1st 3.760 2nd 2.269 3rd 1.645 4th 1.257 5th 1.000 6th 0.843 The pattern - what the casting will look like once poured Dan - You can | .... OR you can ask for help!!! OST Porting service - http://hachiroku.net/forums/showthread.php?t=19991 |
|||
01-30-2007, 12:03 AM
Post: #2
|
|||
|
|||
T50 to AZ6... a "new" option for gearbox issues
I'm not sure. Sounds like alot of work.
|
|||
01-30-2007, 12:57 AM
Post: #3
|
|||
|
|||
T50 to AZ6... a "new" option for gearbox issues
sticky ? At least once your writeup is complete.
I understand the idea but I have seen a guy running GZE's for years and never having problems. ....... maybe you guys can't shift :-D I don't see the need of chaning the gearbox on a AE86 I think its great. But maybe your purpose with it is difrent than mine .... Have you thought of a Supra gearbox ... .As far as I know it fits the AE86 body Cars: "99 Lexus IS200 "86 AE86 Kouki Panda Levin GT-Apex (restore project) "84 AE86 Zenki Blue Levin (project racer) Motorcycles: "02 Yamaha R1 "02 Honda Hornet S "08 BMW R1200GS |
|||
01-30-2007, 01:09 AM
Post: #4
|
|||
|
|||
T50 to AZ6... a "new" option for gearbox issues
T50's can still be found around, and combining them with a shorter FD might be alot cheaper and easier to do. Though miata 6speed is one of the best in the bussiness. Still i think that is a big big mod. At that point you might as well go all the way and swap in a whole engine with tranny (like the honda f20c).
|
|||
01-30-2007, 11:18 AM
Post: #5
|
|||
|
|||
T50 to AZ6... a "new" option for gearbox issues
1. Will such swap require AE86 chassis cutting & welding ?
2. Will it cure the problem with relatively weak AE86 rear end ? The AE86 gears and rear end are limited to ~200hp (or even less). Changing the gearbox only will cure hard shifting problem but power-wise we must change the rear end too. Your idea sounds interesting ! |
|||
01-30-2007, 11:39 AM
Post: #6
|
|||
|
|||
T50 to AZ6... a "new" option for gearbox issues
Interesting post...
But, are you really sure that t50 gearbox is so weak? Just one example. If I check history of my ae85, I can presume that it has been used rough wihtout frequent services. It's 23 years old, and I must say that my gearbox is in good shape (at least by my amateur judgement). Shifting is very smooth. Even on some newer cars that I drove shifting is harder then on ae85. |
|||
01-30-2007, 02:12 PM
Post: #7
|
|||
|
|||
T50 to AZ6... a "new" option for gearbox issues
Very interesting topic.
However I do sense something a bit like commercial posting with all the dollar signs and the "We" part. You guys are familiar with out commercial sales postings? If this applies to you just send me or Mux a pm. Alex: ae85 should not really stress out a T50 since the power output is not that high. Most 4age powered cars should get some difficulties with 2nd and 3rd after 200-250k. 1983 - AE86 Sprinter Trueno - import project 2013 - Honda Civic sport - daily driver 2004 - AEU86 dot ORG - daily domain Support our forum, buy from the AEU86 shop: |
|||
01-30-2007, 02:14 PM
Post: #8
|
|||
|
|||
T50 to AZ6... a "new" option for gearbox issues
banpei Wrote:Alex: ae85 should not really stress out a T50 since the power output is not that high. Most 4age powered cars should get some difficulties with 2nd and 3rd after 200-250k. The torque is almost the same, just RPM range is different (IMHO gears are torque sensitive). |
|||
01-30-2007, 02:16 PM
Post: #9
|
|||
|
|||
T50 to AZ6... a "new" option for gearbox issues
jamiemirror Wrote:The torque is almost the same, just RPM range is different (IMHO gears are torque sensitive).True, but ae85 drivers used to drive a bit differently from ae86 drivers. 1983 - AE86 Sprinter Trueno - import project 2013 - Honda Civic sport - daily driver 2004 - AEU86 dot ORG - daily domain Support our forum, buy from the AEU86 shop: |
|||
01-30-2007, 04:17 PM
Post: #10
|
|||
|
|||
T50 to AZ6... a "new" option for gearbox issues
if the tranny gearing is shorter than more torque comes to the rear diff, and that puts even more stress on the diff. and the first gear is a bit shorter in the miata transmission. Its not that relevant i think..
|
|||
« Next Oldest | Next Newest »
|
Possibly Related Threads... | |||||
Thread | Author | Replies | Views | Last Post | |
OST-026: "My White Hatch" | oldeskewltoy | 49 | 57,692 |
07-03-2014 11:56 PM Last Post: oldeskewltoy |
|
Project "Roku-ju" TA60 Carina | Motax | 24 | 37,401 |
03-05-2014 10:21 AM Last Post: Motax |
|
project "twin cam 16" another AE86... | fax0815 | 11 | 17,811 |
11-19-2011 09:05 AM Last Post: BOOMEX |
|
Supercharged Hachiroku "update" | roadrunner | 20 | 23,803 |
06-02-2011 03:27 AM Last Post: kennedy8383 |
|
4AGZE - REBUILD AE86 NYC's "Black Prophet" | ae86driftmaster | 25 | 37,376 |
02-19-2010 06:18 PM Last Post: ae86driftmaster |
User(s) browsing this thread: 1 Guest(s)