Which Turbo Computer To Use?

cody_i · Jun 4, 2008

I have a turbo 2.3 from an XR4Ti and I'm wondering what computer to use. I have no idea what one to look for. I have the complete engine, wiring harness and the stock VAM. The computer that came with the engine was from an automatic, so it won't do me any good in my manual truck. I have added an intercooler from an SVO as well. I can find a big VAM if necessary, or if it will give me an increase in power. Any knowledgeable suggestions would be greatly appreciated. I hope to have the engine installed this weekend, and would like to get it up and running.
Thanks much, Cody

Davis · Jun 5, 2008

You can use an auto computer in a manual, but vice versa wont work.
Look for a computer from an 87-88 turbocoupe, or from an 86 svo. Those used big VAMs and also were tuned for more power.

cody_i · Jun 5, 2008

Is there a specific one that is better than the other, such as the PE, PK, PK1, PF2, PF3, LA2, or LA3?

red85 · Jun 5, 2008

LA3 is the one that I was advised to use. Mine was in an 88 Turbo Coupe. Once I have my intercooler and big VAM I'll be doing my swap!

cody_i · Jun 5, 2008

Not that I'm planning to do a lot of computer tuning right away, but from what I understand the LA3 is not as easily reprogrammed or modified as the P-series computers.

Sevensecondsuv · Jun 14, 2008

The 85.5-86 SVO computers have the most timing and therefore make the most horsepower (210 I think).

The 87-88 turbocoupe computers (LA, LA2, LA3, LB2, LB3, 8UA) are the second most potent computer at about 190-200 in the manuals (the auto computers - LB2, LB3, 8UA - only let the engine run 9 PSI to save the poor A4LD). However, these six computer's are generally regarded as the "best" because they are set up for the big vam, 35 lb injectors, intercooling, and have much faster processors than the SVO computers. The auto computers are perfectly capable of running an engine with a manual transmission at 15+ PSI, you just have to get an aftermarket boost controller to crank the boost up that much.

Any of the large VAM computer's horse power limit is about 280 due to the fact that the large vam is pegged full open at that air intake rate. You can tighten down the vam spring and increase base fuel pressure to get it to go higher, but you should really be getting a chip and learning to tune so you can convert it to mass-air at that point.

Keep in mind that any of these computers require the large vam and 35 lb/hr brown top injectors.

red85 · Jun 15, 2008

Fast question regarding VAMs: My 94 Ranger has a MAF setup. Do I need the VAM to run my setup? (88 TC LA3, 36# brown tops and an intercooler+T3 from an 88 TC)

Sevensecondsuv · Jun 15, 2008

Yes, to run it stock without modifying the computer you need the VAM that came with the computer. Your MAF sensor has a totally different output signal than the VAM and your engine will not run with a MAF connected where the VAM should be.

You can convert to a MAF setup if you have a tuning device for the computer. You need to change the VAM transfer fuction (programmed into the computer) to work with a MAF sensor installed in place of the VAM. But it sounds like your still a ways from messing with changing code in a computer.

I would reccomend just getting a stock engine management system from a turbocoupe and get everything installed and running right and then start looking at ways to blow it up (by increasing the power!!!!)

Sevensecondsuv · Jun 15, 2008

Also, 87-88 turbocoupes came with IHI turbo's that were quite a bit smaller than any of the T-3's offered in other turbo 2.3 fords. This was because the turbocoupes were heavy and needed the turbo to spool fast - the downside being that IHI's become very inefficient at power levels much over stock. I would reccomend getting a T3 off another turbo ford rather than using the IHI.

I'm running a .48 A/R hot side .60 A/R cold side T3 and it's just about perfect. I get full boost at 2600 RPM's and it's still screaming and pulling hard at 6000.

red85 · Jun 16, 2008

Sevensecondsuv said:
Also, 87-88 turbocoupes came with IHI turbo's that were quite a bit smaller than any of the T-3's offered in other turbo 2.3 fords.

I'm pretty sure my turbo is a T3. It's a .63 AR hot side and it's got AIResearch on the compressor housing. Were the IHI's marked with those same markings? Do I indeed have an IHI?

ejholmgren · Jun 16, 2008

Sevensecondsuv · Jun 17, 2008

red85 said:
I'm pretty sure my turbo is a T3. It's a .63 AR hot side and it's got AIResearch on the compressor housing. Were the IHI's marked with those same markings? Do I indeed have an IHI?

No that sounds like the next size up T3 from what I have. That should be a good turbo for you. Although you probably won't get much boost below 2500-3000 RPMs.

cody_i · Jun 17, 2008

Thanks for the input. I purchased a computer yesterday and will let you know what happens.
Thanks, Cody

napolron · Jul 9, 2008

From what I remember the la2 and la3 out of '87 to '88 turbo coupes were the same the only real difference was the la2 didnt run full boost through the gears. 15psi in 1st and 2nd, 10psi everything else. The la2 is way cheaper on ebay and whatnot just get yourself a gillis valve or something and control the boost yourself.

The auto computers I think were lb2 and/or 3

AllanD · Jul 10, 2008

If you use an external boost controller which computer you use from a thunderbird is irrelevant.

The PE series computers aren't actually as agressive as the LA computers The cars with the PE's came with a bigger turbo than the IHI used on the LA's so most of the power difference comes from the turbo, not the computer.

There were only ever about 8000 cars made with PE computers (all SVO mustangs) There were 45,000 Turbocoupes made in 1987 and another 55,000 in 1988

which computer do you think is more common?

the LA computer has one advantage over a PE.
while the engines made with a PE had an intercooler the computer had no clue what the intercooler was accomplishing because the only point where the air temp was measured in the PE cars was at the VAT (built inside the VAM)

The LA controlled intercooled T-birds used an ACT sensor in the intake manifold AFTER the intercooler so they could "adjust" to intercooler effectiveness under differing conditions.

My choice would be an LA3 computer.

But you'll need to add an ACT sensor to the engine

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