joe44510

OK so i know there has been threads upon threads of this written up there is just so many that i cant read through them all. Basically this is where I stand. I have the opportunity to pick up a 90's t2 motor and tranny from a guy with the wiring harness and I believe the computer but not sure. the motor has already have the front cover changed and the oil pan changed and the 83 motor mounts installed so thats basically ready to drop in but its all the other stuff i would like to get some more info on. like all the wiring tranny setup drive line setup i read the shifter on the tranny has to be moved so info on what to do with that would be appreciated. I want to read the post as they come instead of reading through pages and pages on another post. Any solid links would be appreciated. I understand this isn't going to be easy but i want to get this figured out so i can potentially swap into another 83 that i will be getting with the motor that is race ready.

GySgtFrank

iTrader: (4)

OK Joe, Even though this properly belongs in a different section than the build threads, I'll give you a quick run down. I'm sure others will disagree with me, but I'll give you my best advice.

There are two versions of the FC TII. The 86-87 version that uses the mechanical OMP and the 88-91 using an electronic OMP. It sounds like you're looking at the later version. The easiest way to mount them is with a GSL-SE front cover (for the front engine mount set up) and the GSL-SE oil pan (to clear the stock steering arms). It sounds like this is what you already have, although it is possible to use the 12A front cover if you block off the OMP and pre-mix. (The 12A OMP does not work with the later 13Bs)

You can use the stock harness and ECU, but getting it to interface with all of the controls in the 83 is not easy, doable, but not easy. You will become intimately familiar with the factory wiring diagrams for both years (diagrams are available on SgtFox's site). This will still leave you with the problem of the electronic OMP. The GSL-SE front cover uses a mechanical OMP (the electronic one doesn't fit), which is fine, except that the stock 88-91 ECU has to have the signal from an electronic OMP or it goes into limp mode and will never run right. A few people have come up with work arounds, but I'm not sure how well they have worked out in the end. (such as leaving it hooked up and wiring out of the way.)

The best way is to spend the money on a good current generation ECU and harness. Such as HalTech etc. It's pricey, but worth it in the long run. It gives you the flexibility to make changes and gets rid of the OMP issue. Getting it tuned properly is the biggest drawback with the stand alones. Try to find someone locally that has experience with one of the systems.

As far as the TII transmission the later TII trans had different mounts than the earlier TII and NA transmissions. The mount will have to be fabricated to fit the 83 mounting points. The gear shift lever will be a little further back than the original, but not as much so as the 79 - 80. There are threads on modifying the shift rails on the tail shaft housing if you don't want to modify the shifter opening. The TII used a different tail shaft yoke than the NA and FB/SA yokes (which were the same). You will need to modify an FB shaft to use a TII front yoke with the early FB rear yoke if you have an early small bearing rear end, or a later rear yoke (84-85) if you have the later big bearing rear end. Be advised the U joints in the stock drive shafts of the 83 and up are not replaceable, Mazda in their infinite wisdom wanted you to replace the whole drive shaft. MazdaTrix has drive shafts with replaceable u-joints and would probably be able to help you out on this as it's a relatively common swap.

An alternative to dealing with the standalone would be to swap the entire front K member from an FC into the 83 for the better brakes, spindles, and rack and pinion steering. Then you could use the late TII front cover and oil pan with the FC engine mounts. Allowing the use of the stock ECU/harness and the electronic OMP. You still have to deal with making it all work with the 83 controls however. This swap has also been covered and brings up it's own issues.

As you said, it's not easy. But where there's a will there's a way.

joe44510

Ok so the easiest way to deal with the wiring is us a haltech system? The guy im getting the motor from said he was going to use that and knows a guy who is able to tune them pretty well. and i believe he said he already covered the omp spot since he was going to use the haltech system. as for the shifter if i just modify the shifter opening how far back will it sit? and it sounds like you have done this before, so one other question was it worth it????

joe44510

oh and what type of HalTech do you recomend?

GySgtFrank

iTrader: (4)

I didn't do the TII swap, but the NA swap with EFI using the stock ECU. I was looking for stock reliability, but using the carburetor with the NA swap is far easier. The stand alone would have made the EFI swap easier as well. In your case you have the turbo system so using the EFI is going to be necessary, unless you wanted to put a bunch of money into manifolds, carb, etc. Sticking with the EFI in your case would be a lot better IMO. Either way it's going to take a little money to complete the swap so you might as well go with the better set up.

Which system to use depends on your goals and plans for the engine. I would recommend a current generation system as they are quite a bit better than the older systems. It really depends on what you can afford, buy the most capable system within your price range.

I thought it was worth it, and the folks that have done the TII swaps have been very happy with the results. At stock boost levels the rotary does very well. When people get in trouble is when they start chasing the boost bug and pop their engines at high boost levels. The good part is that your later TII will handle more boost the early TIIs.

The shifter will be about an inch or so farther back. I have the early SA so my shifter opening was farther forward, others have said the 83 and up opening is a little further back. The only way to tell for sure is to test fit it and see which way you prefer to go. Modifying the shifter doesn't look to be all that hard. I moved my shifter back as I didn't like the stock shifter position and modified the sheet metal for the opening instead.

GySgtFrank

iTrader: (4)

addendum: The new systems also have the harnesses available, which you will need as you are doing a custom set up.

joe44510

ok so i have never used a custom ecu before and am not to familiar with haltech and other system what is the difference between all the different type of haltech ecu's?

GySgtFrank

iTrader: (4)

price and capabilities. I've never used them, but if you read up on their site they have full information. Which one is right for you depends upon your plans for the build and your budget. The data logging function will be important especially if you don't have ready access to a dyno for tuning. Talk to the person that will be doing the tuning, they should be able to steer you to the system that works for you.