MPFI N/A Horizon

[1986GLH]

My brother and I started rebuilding an engine for my 87 Horizon this spring. The car has never run the greatest and always sounded horrible in the higher RPM's. It has always leaked oil too. So the Friday before Labor day the car started running even worse and was leaking oil more than normal. I lost a half quart driving 30 miles. Turns out that one of the bolts holding the fuel pump on backed out and was missing. My brother and I have talked about doing MPFI with Turbo I electronics and decided to give it a try. It now has an 84 block with 88 SMEC electronics in it.

The old engine.
http://i282.photobucket.com/albums/kk261/1986GLH/IMG00115-20100903-1404.jpg

The rebuilt engine on the stand.
http://i282.photobucket.com/albums/kk261/1986GLH/IMG00124-20100906-1256.jpg

http://i282.photobucket.com/albums/kk261/1986GLH/IMG00125-20100906-1300.jpg

Engine in the car.
http://i282.photobucket.com/albums/kk261/1986GLH/IMG00126-20100906-1455.jpg

How it is sitting right now.
http://i282.photobucket.com/albums/kk261/1986GLH/IMG00136-20100906-2127.jpg

[86Shelby]

Interesting. What are you doing for a calibration?

[1986GLH]

Interesting. What are you doing for a calibration?

Just going to use the stock 88 T1 calibration for now.

[shackwrrr]

Just going to use the stock 88 T1 calibration for now.

1 bar map? If so its going to be rich. If you go to the 2 bar it might be lean. Call up rob or use a AFPR.

Something I wanted to do for a MPG monster.

[135sohc]

I'm very interested to see how this turns out and runs. Will be doing something very similar to my dd Shadow someday when the stars and bank account align to let me do everything I want to do to really make a strong n/a engine.

I believe the potential of a really dialed in and built mpfi n/a 2.2/2.5 is alot more than most people are willing to think it is.

[turbovanman²]

Run the stock turbo 2 bar and don't go to WOT, it will run just fine or get it recalibrated or find a flex fuel computer.

[Vigo]

Get a narrowband afr gauge (close enough for N/A work) or tap it with a voltmeter temporarily for tuning purposes and see if it goes super rich at WOT. If it does, i think the easiest thing to do might be a 'Map Clamp' i.e. limiting the voltage coming out of the map sensor so that the computer never 'sees' 0 vacuum. That can be done with zener diode just like people used to do to get around the overboost shutdown. Although, i dont know how that affects the computer's BARO reading.. If you use an AFPR it will lower the pressure EVERYWHERE, i.e. at idle and midrange so it might cause the car to idle or drive bad before it goes into closed loop. I biult my own AFPR out of a log-motor FPR though, so it can be done almost free if you have the tools.

So is this a low compression turbo motor? I hope not.. because they barely move without boost. The tbi motor is MUCH stronger than an off-boost turbo motor.

Also, unaclocker built an NA mpfi rampage at one point and got it to do 42mpg highway (5spd of course) but he was running it on megasquirt and i dont know how much of that MPG was based off the tuning he did with megasquirt vs what it would do on a stock cal.

[turbovanman²]

It goes super rich, when I lost my turbo, I drove around, it was fine except when I hit wot, it would go pig rich and bog badly, :(

Agreed on tricking the computer so it never see's WOT.

[1986GLH]

It is a 2 bar map. Won't it only get rich if the Map is seeing boost? When my GLH wasn't boosting right it ran fine at WOT. It was only getting boost at 4k rpms and under that there was no boost and it ran fine.

[turbovanman²]

It is a 2 bar map. Won't it only get rich if the Map is seeing boost? When my GLH wasn't boosting right it ran fine at WOT. It was only getting boost at 4k rpms and under that there was no boost and it ran fine.

WOT is preprogrammed so it doesn't care if boost is present, it dumps a preset amount of fuel. 4000 rpm isn't the factor, its your right foot.

[contraption22]

How about a zeiner diode for the TPS? Think that might help?

[Vigo]

Doing it on the TPS would get around any BARO read problems (which i might have made up..) but i dont know if the computer only uses MAP or TPS or a combination of both to determine when to go open-loop. If limiting the TPS signal keeps it from going to open loop when you floor it that should do the trick.

[contraption22]

Thinking about it some more, this may not be a good solutuion, depending on what fuel and ignition the engine needs at WOT.

Ideally, the best solution would be a custom cal.

Not knowing much about building calibrations, is it possible to simply take the Mexican or Flex fuel SBEC tables and put them into a SMEC chip?

Also, is it possible to get a TBI computer to fire 4 injectors?

[1986GLH]

Doesn't the computer determine how much fuel to inject based on what the map sensor is reading? Yes at WOT there is a predetermined amount of fuel but it is based on what the map sensor is reading. When you adjust the boost the amount of fuel is also adjusted. So when it isn't seeing boost it shouldn't be adding a lot more fuel. Yes it may run a little rich at WOT these cars always do.

[turbovanman²]

Thinking about it some more, this may not be a good solutuion, depending on what fuel and ignition the engine needs at WOT.

Ideally, the best solution would be a custom cal.

Not knowing much about building calibrations, is it possible to simply take the Mexican or Flex fuel SBEC tables and put them into a SMEC chip?

Also, is it possible to get a TBI computer to fire 4 injectors?

Its easy to take out the fuel.


Doesn't the computer determine how much fuel to inject based on what the map sensor is reading? Yes at WOT there is a predetermined amount of fuel but it is based on what the map sensor is reading. When you adjust the boost the amount of fuel is also adjusted. So when it isn't seeing boost it shouldn't be adding a lot more fuel. Yes it may run a little rich at WOT these cars always do.

Not really, WOT is preset, that's it, good night. When it see's it, it starts dumping fuel, it probably does use a bit of the MAP but it will go pig rich at WOT without boost. Tweaking the cal is easy to fix that.

[contraption22]

The transition from vacuum to boost, in my understanding, is the hardest area of the MAP to tune for. Weird things happen there.

[contraption22]

Not really, WOT is preset, that's it, good night. When it see's it, it starts dumping fuel, it probably does use a bit of the MAP but it will go pig rich at WOT without boost. Tweaking the cal is easy to fix that.

Huh? The computer needs SOME input to calculate fueling. It uses MAP sensor input primarily for this at WOT.

[turbovanman²]

Huh? The computer needs SOME input to calculate fueling. It uses MAP sensor input primarily for this at WOT.

Ok, probably alot more but still, it see's WOT and goes into a fixed fuel mode, Rob can add more info.

As for fixing it, its not that hard, you simply rescale the fuel maps, sure it might not BE bang on, but should be pretty close.

[1986GLH]

Huh? The computer needs SOME input to calculate fueling. It uses MAP sensor input primarily for this at WOT.

My point exactly! So whether it reads no boost or 13 lbs of boost the computer will adjust it based on what the MAP sensor is seeing.

[84omni]

Not really, WOT is preset, that's it, good night. When it see's it, it starts dumping fuel, it probably does use a bit of the MAP but it will go pig rich at WOT without boost. Tweaking the cal is easy to fix that.

We will all find out hopefully after this weekend what the cal does as we should have it all together. We will hook up a dvom and check if if gets rich at wot. If that is a problem then we either need a custum cal of just stay off wot as this is a dd not a race car.

[contraption22]

My point exactly! So whether it reads no boost or 13 lbs of boost the computer will adjust it based on what the MAP sensor is seeing.

In theory, you are correct. However, the actual fueling table for a N/A motor at WOT and a Turbo motor in vac/boost transition may be greatly different. I can't say that this is the case, but it could be.

[1986GLH]

In theory, you are correct. However, the actual fueling table for a N/A motor at WOT and a Turbo motor in vac/boost transition may be greatly different. I can't say that this is the case, but it could be.

Good point... I'm hoping for the best.

[TheCanadian007]

Are you running turbo dished pistons or TBI/carb flat top pistons?

If you don't do anything with the calibration or injector size, it will run pig rich at WOT and bog down; the map sensor can't take that much fuel out and the SMEC will pull timing down at WOT too.

[thedon809]

I have been contemplating something similar. I was thinking more along the lines of individual throttle bodies, 12:1 compression, heavily ported head, long tube header, big --- cam. I wonder if 180whp would be possible? There's a neon that made 219whp with the sohc 2.0. Their heads flow a little bit better than the 8v though.

[Vigo]

I wonder if 180whp would be possible?

I think it is. I talked to a user named 'allmotor' iirc on the 'other' site about his n/a builds and he made it sound like 200+ crank hp was a sure thing if you built it a certain way. He claimed to have had a 200hp n/a 2.2 in a minivan at some point.

[thedon809]

I think it is. I talked to a user named 'allmotor' iirc on the 'other' site about his n/a builds and he made it sound like 200+ crank hp was a sure thing if you built it a certain way. He claimed to have had a 200hp n/a 2.2 in a minivan at some point.That's going to be my next project. I will probably pick up a charger at some point and see if I can make a 13 second all motor 2.2. Whats the highest FD 5 speed available for these cars?

[84omni]

Finished a few things on the horizon tonight and took it for a spin. Hooked a volt meter to the o2 sensor and while cruising it was switching around the .45v and at wot it was steady at .75-.76v not too bad for having t2 injectors with a 88 t1 computer in it.

[1986GLH]

As my brother said the Horizon ran really well. Way smoother than the old carb engine. I was a little worried that it might knock a little with the higher compression ratio since it is an 84 block with the flat top pistons with a swirl head on it. But there was no knock that we noticed. Can't wait to see what kind of mileage it will get now with the MPFI and 3.05 final drive!

[Vigo]

The lowest final drive gearing in any of the 5 spds is 3.85 or 3.87..

[ShelGame]

The computer will switch fuel tables at WOT, and the WOT table is MUCH richer than the P/T table which is why it goes pig rich. Turbo cars want it rich at WOT to keep things like the piston tops cool. For the MPFI, you could easily just scale down the WOT fuel table a few percent to pick up some power and economy.

The computer uses either TPS or MAP to switch to open loop and the WOT tables. Basically, anything over ~60% throttle is WOT, and any time you are in boost is open loop and the WOT fuel table is used. Obviously, you won't be getting into boost with an MPFI setup.

Also, since it's not turbo, you could bump up the TPS reading to switch to WOT. Move it up to say 80% and you would stay closed loop longer. Which should also improve the fuel economy.

The Flex-Fuel computer used 3D tables like the T3. So, you could not simply copy those tables over. The Mexican cals were 2D I think, but again, the code is different from the US computers, so you can't copy them over. The TBI computer can't run 4 injectors. Though, the code will run on a turbo computer. So, I suppose you could expand the TBI code to run the 4 injectors. I just don't think it would work as well as the turbo code does. It would also probably be tough to 'scale-down' the turbo code to run a 1-bar MAP. There are too many assumptions in the code for boost.

[contraption22]

What I was wondering if there is an external device you could use to get the TBI puter to run 4 injectors.

[Vigo]

People have been running all 4 injectors on the TBI's single injector driver ever since they started doing this 1pc manifold conversion on n/a cars.

However, plenty of aftermarket engine controllers have options for external injector driver boards. In fact, are the injector drivers themselves on the power module? If so you could just wire the harness to use a turbo power module with the TBI computer and just signal all of the drivers off the one signal coming from the tbi computer.

But in either case that would be for someone who didnt already decide to use the entire turbo harness/computer in the first place.

[contraption22]

People have been running all 4 injectors on the TBI's single injector driver ever since they started doing this 1pc manifold conversion on n/a cars.




Do you know of anybody that has done this with success?

[ShelGame]

People have been running all 4 injectors on the TBI's single injector driver ever since they started doing this 1pc manifold conversion on n/a cars.

However, plenty of aftermarket engine controllers have options for external injector driver boards. In fact, are the injector drivers themselves on the power module? If so you could just wire the harness to use a turbo power module with the TBI computer and just signal all of the drivers off the one signal coming from the tbi computer.

But in either case that would be for someone who didnt already decide to use the entire turbo harness/computer in the first place.

That's not a bad idea at all. Though, with a turbo computer, you at least get 2 batches of injectors instead of only 1...

[Vigo]

Do you know of anybody that has done this with success?

Many years ago i sought out and talked to (online) a handful of people who had done it. I dont remember much of anything about it at this point, though..:o

[contraption22]

Found this. Don't know the reliability of the source.

http://technovir.us/dodge-2-2l2-5l-tbi-to-mpi-system-conversion/

[Vigo]

I skimmer over it and it all seems plausible/correct.. touches on some of the major points i remember like 19pph high impedance injectors, etc.

Its really an impressive writeup considering how small the audience for it would be..

[1986GLH]

So it's been forever since I updated this thread. I have been daily driving the horizon for most of the last 5 years. I've put 26k on it with the MPFI and it still runs great.

[2.216VTurbo]

Nothing like a good 'Ole back from the dead thread but as I recall the million dollar question back then was what kind of mileage you were gonna get from it;). So??

[1986GLH]

I average anywhere from 28-32 mpg normally. With the ac on it brings it down to 26-28.

[GLHS60]

It sounds like a success to me !!!
Congrats.

Thanks
Randy

[WarlockSyno]

What all did you swap over to do this? All of the sensors, harness, and ECU? I want to swap over my '89 3-speed auto N/A to MPFI, I have a '89 3-speed T1 ECU, One piece intake, T2 injectors, and turbo alternator. Any idea on what else I would need?

[contraption22]

So it's been forever since I updated this thread. I have been daily driving the horizon for most of the last 5 years. I've put 26k on it with the MPFI and it still runs great.

Sweet! Is this on unmodified turbo electronics?

[84omni]

We used a complete turbo harness and sensors and it's been running on a stock 88t1 smec with 2 bar map.