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'91 NA Tuning with '85 Turbo

1645 Views 3 Replies 4 Participants Last post by  mike d
Hey, New member here. I have been over at Saab Central but nobody there seems to be interested in tuning NA Saabs, so I'm hoping for some guidance and advise here.

Background: A few years ago I picked up a 1985 Saab 900 Turbo. Bought it fairly cheap, as the previous owner needed to get rid of it quick and didn't really know what she had (it had changed hands a few times recently, but the original owner had it for 20+ years).

Engine currently has a mere 132K on it, but the body is rusting away to the point that it is getting dangerous to drive, the gas tank is being held on with bungy cords and the rear shocks could crash through at any point.

However, the 2.0 turbo motor is still great! So I began the search to find a newer body to transplant it into. What I ended up with was a 1991 2.1 NA 900 that had been sitting in a driveway, undriven for the last 7 years :)

The owner said it had engine, transmission, and brake problems, but didn't really know what. It was dirty as hell, but looked rust free and like a decent candidate for my engine swap.

I bought it for $100 and spent a day cleaning it, then thought I'd try to get it started just to see what I had. Changed out the spark plugs, cap & rotor, oil change and new fuel filer, added fresh gas and an additive to help it out. New battery and she fired up! Cool! I let her idle for a bit and then drove her home.

Brakes were good, it just needed a new pedal return spring, Transmission has a bad syncro in 2nd gear but it's still driveable. The engine is a little noisy, but I'm not sure there is any major issue.

So now I'm trying to figure out what to do with these 2 cars to make 1 GOOD 900.

Option 1 - Transfer the entire engine and transmission from the 1985 Turbo into the 1991 body. However, the wiring harness from the '85 is crap, the insulation is falling apart and it wouldn't survive the transfer. So Then I run into problems trying to use the '91 harness with the LH2.4.2 and EZK. Don't know how this will work with the '85 Lh2.2 and ACP.

Option 2 - Tune the 2.1 NA engine with parts from the '85 turbo. I kinda like this idea as the NA engine only has 136k on it and would keep me from having to hassle with the electronics. I have heard that the '85 turbo head was espically well suited to swap onto the 2.1 block, as long as I port it to match the 2.1 header. I could also use the '85 turbo exhaust cam and downpipe, muffler, exhaust for better flow. I could even change out the transmission as well as to eliminate the bad 2nd gear syncro.

Any thoughts, ideas, or rants on this? A how bout a vote on which option is the better plan?

Thanks!!!! :thumbup:
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In all honesty I would prolly look at doing a Low Pressure Turbo T5 swap on the NA and don't even bother with the 85 at all..

I am thinking base boost on a 2.1 motor with T5 swap might be the business:winky:

you have options just need to think it through..

from where I stand the only thing good from your 85 is the Short block and the exhaust cam.

I would send the rest of the car to its maker.
^ Bingo. I have always wanted to mess with an N/A motor running T5 with a turbo. One of our members did just that, I'll see if I can get some info.
use these parts

91 na head and intake assembly, 85 turbo block, and whatever trans shifts better

Run t5

have a rocket ship of a car

do not reuse the 1985 head, they are crap, and cause lots of detonation issue when tuning

let me know if you need help with the t5 stuff, ive done it a few times

Mike d
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