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Discussion Starter #1
Hello,

If anyone knows what tortures I may face during this project, please feel welcome to share them. My goal is to incorporate a T1 system with my 2.5 liter 1990 Sundance, using a 1991 Turbo computer with a 5 speed manual.

I am specifially interested in which idosycricities can result from using an auto transmission computer with the manual trany. Another question is wether the tachometer from the auto will work with the manual transmission?

Additionally, if I add a 5 speed to my car, currently with a TBI auto computer, will it work well or do I need to source a manual computer?
 

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Tachometer should be plug-and-play; at least it was on my Spirit. The plugs are there, they're just unused. From what I understand, the code in the computers is slightly different, but I don't think you'll be doing any serious damage by using one over the other. I would get an opinion other than mine on that.
As for putting in a turbo... that's an entirely different animal. You're going to need AT LEAST the turbo manifolds, the ENTIRE turbo harness with sensors, bits of turbo vacuum harness, a turbo computer, not to mention probably an entire turbo head-- turbos have hardened seats and exhaust valves, as well as a different cam. On top of that, it's probably a very good idea to put in turbo pistons (lower compression ratio than TBI pistons), non-lightweight rods (the TBI cars used lightweight rods, and while I've heard that some 2.2 T1 setups used lightweight rods, I don't know if that held for the 2.5 T1) and a forged rather than cast crank. You're also going to need a different head gasket to handle the boost pressures and cross-drilling. So basically, yes, it is a TON of work.
Now, I'm in much the same boat as you, I want more power, and I've been considering going turbo eventually. My current plan of action is move out of my folks' house/graduate from college, and then do the following:
1. Get a 2.2 Turbo I motor and electronics from... wherever I can, preferably one with a spun bearing/blown piston rings/whatever. The point is, get a turbo engine with enough substantial damage to the lower end that it's worth essentially nothing, but with no real damage to the top end.
2. Get a common block 2.5 motor with a cracked or warped head. Sadly, this will probably be the easy part.
3. Strip the lower end of the 2.5 block down, check it all out, hot tank and paint.
4. Swap anything I can salvage from the 2.2 over onto the 2.5 block, and put in 2.5 turbo pistons (since the 2.2 and 2.5 were common block after '89-- what I am aiming for-- the 2.5 used a shorter piston).
5. Plumb up the turbo and install any other bits and pieces I need (manifolds, etc.)
The idea then would be to get up VERY EARLY on a Saturday to pull the TBI engine out of the car. With the engine out of the way, I'll have the room to do the harnesses. Then, drop the turbo motor in, close up shop for the night (I'm assuming that getting everything ready will take most of Saturday). I then have all of Sunday to get the car driveable to take to work on Monday. I only lose the car for a weekend, and I get a known good engine in there. I would run stock stuff until I got the chance to do some upgrades to the transmission and put in a boost gauge, etc., but those are things that can come with time. This way, I have a driveable car the whole time. Someone ran ridiculously good times in a Reliant with the 3-speed with some upgrades to it. Because I have bench seats, I would have to get new seats to put in a 5-speed, which is not something I want to do. Besides, I like my cars to be sleepers anyway...
 

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B10alia has the right idea, have the engine ready and set up with the proper components on hand and ready to go. There have been several guys/gals which have put a manual transmission in a vehicle that had the auto computer without any issues whatsoever so that is not the issue, it is making sure you have all the parts needed to put the whole thing together.B10alia has a very good starting list he needs and would recommend you follow (means of getting the components is up to you, a donor car is always a good thing, pull and swap everything at once is always a plus), but remember, you need the pedal assembly specific to your car, someone else knows the specifics of that, not sure which models will work or if she happens to be a year specific setup. Being a 1990, as a T1, your parts list could be smaller, turbo pistons, turbo rods (always be safe here), forged 2.5 crank if you can get one, and turbo head and camshaft, T1 computer you mentioned, wiring harness, manifolds, turbo, and a few other turbo items on the list.
 

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The only real problem that seems to come up using an auto computer with a manual transmission is a tendency for the idle to hang or be slow to return to idle. But often there isn't any problem so I'd try it first and swap only if an issue comes up.
 

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Discussion Starter #5
B10alia, Dana44 and valiant67;

At least one person smarter than I suggested changing to a manual 1st for economy, yet another suggested swapping in a turbo for power. I have begun gathering the parts for the turbo but realise that I may be happy with just the 5 speed for now.

I can get a 94 TBI manual transmission computer to run my car with a 5 speed but I don't have all the turbo stuff yet, nor the time or spare vehicles, let alone afford it.

I am not unhappy waiting for power, performance remains a necessity.

Will a 94 TBI manual computer be happy with my 90 auto car with the addition of a 5 speed?
 

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Manual to manual, but the thing to check is the wiring compatability between the 90 and 94 model years, sometimes there are things that change, I don't know that specific, but, if it does, verify the sensors and locations on the engine as far as function goes, would really hate to have things set up to, for example, fire on number one cylinder but the sensor takes its feed off cylinder four, but one thing we all forgot was the fuel pump setup for the injectors over the throttlebody. there is a pressure difference of 7, 14, and 45-54psi with different intake setups.
 

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I would leave the original ECM in there. The swap to manual means that the computer will not flare the idle up between shifts, so it may drop just a little low instantaneously. This may or may not be that noticeable. But the manual computers drive the AIS so that the idle doesn't sag when you push the clutch in to shift.

Going from auto to manual, you will notice a definite increase in power to the wheels. And it's more fun. And you can push-start it in a pinch.
 

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Your Caps Lock key seems to be stuck when making thread titles ;)
 
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