putting a carb. engine in front of auto. trans.

[abcus]

I tried to look this up on the threads; but maybe I did not use the right terms. I am thinking of putting a carburated 1986 1.8 liter engine in front of an automatic transmission that was behind a 1989 turbo 1.8 liter engine. What would be the problems? Both are 4 door wagons.

Thanks,

abcus

[86BRATMAN]

The ea82t should have a 4eat Computer controlled transmission. At the abolsute least you'd have to do a boat load of wiring to get it to function halfway correct.

[calebz]

Should work just fine if its a 3AT

 

Kind of a waste of a turbo car though

[daeron]

Should work just fine if its a 3AT

 

Kind of a waste of a turbo car though

 

Agreed; what were the problems with the turbo engine??? The heads at least should be the same, right guys??

 

second the motions, 4 speed EAT, problems and difficulty but doable. 3AT, straight swap.. but there will be things on the car that complain (CEL wont work, will always be lit for instance) since you have ripped the computer's "body" out but not its brain.. the brain will get "phantom pains" and try to tell you that sixteen million things are going wrong.

[mikeshoup]

If its a 4 spd, it is impossible. The carb does not have a throttle position sensor which the 4spd requires.

 

If its a 3 spd, then no problem at all.

[GeneralDisorder]

If its a 4 spd, it is impossible. The carb does not have a throttle position sensor which the 4spd requires.

 

Correct - I believe it also requires a MAP signal from the computer. If you were industrious enough it could be done with some creative circuit design and fabbing up the TPS to the carb throttle.

 

If its a 3 spd, then no problem at all.

 

Well - all except the fuel system which has to be rewired through a carb FPCU (if you want it correct and safe), and the system run off a carb pump rather than the hi-pressure MPFI one.

 

GD

[mikeshoup]

Well - all except the fuel system which has to be rewired through a carb FPCU (if you want it correct and safe), and the system run off a carb pump rather than the hi-pressure MPFI one.

Ah c'mon, BGD told us he could run his carb off of a 45PSI pump with a pressure regulator

 

If BGD could do it, then we could do it.

[Gloyale]

Correct - I believe it also requires a MAP signal from the computer. If you were industrious enough it could be done with some creative circuit design and fabbing up the TPS to the carb throttle.

 

 

 

Well - all except the fuel system which has to be rewired through a carb FPCU (if you want it correct and safe), and the system run off a carb pump rather than the hi-pressure MPFI one.

 

GD

 

4eat only needs a TPS signal. Nothing else form engine, doesn't *talk* to ECU. No MAP signal( no EA82's even have a MAP, they have MAF's) I'll bet you could mount a TPS on the carb throttle shaft.

 

Carb FPCU? are you talking for *feedback system*? Cause 4wd non-Cali model carbed don't have an ECU at all. High pressure pump would be too high pressure. easy to swap a carb on though.

 

ABCUS, is this car a 2wd or 4wd. If it's 2wd, it has a 3AT, and the swap would be pretty simple. If it is 4wd, it has a 4EAT and would require the TPS to work correctly (although it would still drive without it)

 

either way the Fuel pump is an issue. You could get any cheap aftermarket electric pump.

 

 

Daeron, no the heads are not the same at all. In fact that's the big physical difference between Turbo(MPFI) and the others(Carb, SPFI) other than the pistons. MPFI have dual intake ports, all others are single.

 

I agree this would be a bit of a waste of a turbo car

[abcus]

I have two 4wheel drive cars. The reason I was thinking about doing it was because the best engine from my backup Subarus was a carb engine. The turbo engine may have a blown head gasket. I will have to do some more checking . I may be getting in over my head.

Thanks for help so far,

abcusuote=Gloyale]4eat only needs a TPS signal. Nothing else form engine, doesn't *talk* to ECU. No MAP signal( no EA82's even have a MAP, they have MAF's) I'll bet you could mount a TPS on the carb throttle shaft.

 

Carb FPCU? are you talking for *feedback system*? Cause 4wd non-Cali model carbed don't have an ECU at all. High pressure pump would be too high pressure. easy to swap a carb on though.

 

ABCUS, is this car a 2wd or 4wd. If it's 2wd, it has a 3AT, and the swap would be pretty simple. If it is 4wd, it has a 4EAT and would require the TPS to work correctly (although it would still drive without it)

 

either way the Fuel pump is an issue. You could get any cheap aftermarket electric pump.

 

 

Daeron, no the heads are not the same at all. In fact that's the big physical difference between Turbo(MPFI) and the others(Carb, SPFI) other than the pistons. MPFI have dual intake ports, all others are single.

 

I agree this would be a bit of a waste of a turbo car

[zyewdall]

Well, the first problem would be it would be really really slow, instead of just slow. It sounds like you have two wagons - -why not transplant both the engine and the tranny from the '86, and get rid of the auto tranny?

 

I was also going to suggest just putting the longblock from the '86 into the turbo car, with all the turbo stuff, till I remembered that the turbo engines have the completely different heads for the MPFI. And if you are going to switch heads, why not just redo the head gaskets on the turbo engine. Actually, head gaskets are not that hard, compared to the control issues of changing the engine control system.... I'd just do that, and you'll still have a turbo car.

[daeron]

Well, the first problem would be it would be really really slow, instead of just slow. It sounds like you have two wagons - -why not transplant both the engine and the tranny from the '86, and get rid of the auto tranny?

 

I was also going to suggest just putting the longblock from the '86 into the turbo car, with all the turbo stuff, till I remembered that the turbo engines have the completely different heads for the MPFI. And if you are going to switch heads, why not just redo the head gaskets on the turbo engine. Actually, head gaskets are not that hard, compared to the control issues of changing the engine control system.... I'd just do that, and you'll still have a turbo car.

 

Agreed, the most potentially painful aspect of doing the headgaskets are frozen intake manifold bolts, and milling the heads.. Machine work is no big deal, and well, just.. Good luck with the intake manifold bolts. Mine were fine, but apparently they like to be stuck. Youwould be in for a little more mechanical work than in changing the motors, and a LOT less electrical work in re wiring the ignition system, replacing the fuel pump, and eliminating the ECU.

 

I am sure that you could find a simple way to set it up to run with the carbed engine in the short term.. but if you want to try that, I could only recommend that you embark on the project with an FSM or two, and a thorough understanding of the contents before you begin. You are also liable to need some things from a donor vehicle, but I couldn't say off the top of my head.

 

If you are thinking of this as a temporary running solution "until" you can fix the turbo motor, then it might be viable, but it IS likely to be less simple than one might think. Unless you already have all conceivable parts needed, though, it would likely be less expensive to replace the head gaskets on the turbo engine.

 

What is up with the turbo engine that has you saying "may have a blown head gasket?

[GeneralDisorder]

4eat only needs a TPS signal. Nothing else form engine, doesn't *talk* to ECU. No MAP signal( no EA82's even have a MAP, they have MAF's) I'll bet you could mount a TPS on the carb throttle shaft.

 

I can't recall off the top of my head but I think the MPFI/Turbo ECU's have a MAP inside the ECU. It's used for altitude compensation, and does not require an engine hookup as it's there to read atmospheric pressure.

 

Carb FPCU? are you talking for *feedback system*? Cause 4wd non-Cali model carbed don't have an ECU at all. High pressure pump would be too high pressure. easy to swap a carb on though.

 

FPCU = Fuel Pump Control Unit, and all carbed subaru's have them. Very important safety feature that should not be bypassed.

 

GD

[Gloyale]

I can't recall off the top of my head but I think the MPFI/Turbo ECU's have a MAP inside the ECU. It's used for altitude compensation, and does not require an engine hookup as it's there to read atmospheric pressure.

GD

 

MAP= Manifold Absolute Pressure sensor.

 

There is a device inside the ECU that monitors altitude (by atmospheric pressure) but it is not a MAP like they are used in GM, Dodge, other applications. It is just to give the ECU an ialtitude reading and does not have anything to do with the TCU for the 4EAT(not in 89 anyhow, perhaps in later 95+ versions, perhaps)

 

FPCU, yeah I figured that out soon after I logged off last night.

[daeron]

MAP= Manifold Absolute Pressure sensor.

 

There is a device inside the ECU that monitors altitude (by atmospheric pressure) but it is not a MAP like they are used in GM, Dodge, other applications. It is just to give the ECU an ialtitude reading and does not have anything to do with the TCU for the 4EAT(not in 89 anyhow, perhaps in later 95+ versions, perhaps)

 

FPCU, yeah I figured that out soon after I logged off last night.

 

it IS an identical sensor.. its just that one is sensing manifold absolute pressure and one senses atmosphere "absolute" pressure.

 

but why dicker about it?

[GeneralDisorder]

MAP= Manifold Absolute Pressure sensor.

 

There is a device inside the ECU that monitors altitude (by atmospheric pressure) but it is not a MAP like they are used in GM, Dodge, other applications. It is just to give the ECU an ialtitude reading and does not have anything to do with the TCU for the 4EAT(not in 89 anyhow, perhaps in later 95+ versions, perhaps)

 

As daeron mentioned, the actual sensor itself (regardless of where they are located) is generally refered to as a MAP sensor even when not used for manifold pressure. In the MS world for example, the MS control units have two of them - one for manifold pressure, and one for atmospheric - both are refered to as "MAP sensors". Either way it's a nomenclature difference - the part used is the same.

 

GD

[Gloyale]

As daeron mentioned, the actual sensor itself (regardless of where they are located) is generally refered to as a MAP sensor even when not used for manifold pressure. In the MS world for example, the MS control units have two of them - one for manifold pressure, and one for atmospheric - both are refered to as "MAP sensors". Either way it's a nomenclature difference - the part used is the same.

 

GD

 

 

I see what you're saying. Both are pressure sensors.

 

My point was just that it's not used to sense Manifold pressure, just atmosphereic(for alltitude adjustment)

 

And at any rate it doesn't have anything to do with the transmission on an 89. The only signal from the engine that the TCU needs is from the TPS.