Saab 900 SPG performance upgrades?

I am starting with the basics on the 88 SPG rescue. Plugs, wires, vacuum hoses, filters, fluids, throttle body and IAC cleaning and cleaning 26 years of goo from under the hood. But am dreaming of more...A little more burble to the exhaust. Header and downpipe wrap(?) More whistle to the better turbo(which would be?) Bigger better intercooler. Red box. New racy rubber. Super Aero wheels. Fresh shockers and struts.(Bilsteins?) New bushings. (poly?)Freshened up and improved brakers. Proper gauges. Short throw shifter. Momo Monte Carlo wheel. What is my Imagineering lacking? Beside money...

Trionic 5.

A few spare transmissions?

the T5 swap is nice.. and it is basically the stock injection system from the later NG900 and 9000. It is tunable from the factory with a laptop, connector, and program

For suspension, I really like Bilstein HDs and bigass swaybars on these cars. A wider, lighter wheel would serve you better than the Super Aeros, but I totally understand the desire to keep that 'in the family' look. It doesn't take much to be lighter than Super Aeros.

I've not done a T5 conversion yet, but it really does seem like the way to go for a clean EMS install on a C900. If you don't want to go that far, a 2.8 or 3.0 FPR, redbox APC or tweaked regular APC, and freer flowing exhaust wakes them up very nicely. Both of my remaining C900Ts are factory redbox cars, and I've been impressed with the difference between them and the others I've owned.

If you're interested, I may have a spare short shifter (likely Saab Savior) and I definitely have a spare redbox APC and FPR.

I agree that the Super Aeros are -heavy-. I have a set on my 900 Turbo

Yes Powar. Do tell about the red box and the short shifter!We Worked on the car in the dark last night. Definitely more interesting.

the old 900 is an interesting car. Once you figure out the logic to how it is built.. it becomes a very simple car. Check out the driver's side engine mount. it's almost like one of those metal bar puzzles, once you figure out the magic bolt, it just slides apart

Not many 4x108 wheels on the market. Especially period correct ones...I did find a set of European wheels that looked sort of like Sterns last night but they cost more than two of my parts cars combined. Suggestions? The 10 year old and I have been replacing vacuum hoses, cleaning throttle body, Mass air meter and IAC. Tonight was the test of how we had done. And how satisfying it is to make the old SPG run that much better. Great seeing my little buddy smile as we ran through the gears!

ls1fiero wrote: Yes Powar. Do tell about the red box and the short shifter!We Worked on the car in the dark last night. Definitely more interesting.

I've been poking around and the shifter assembly appears to be MIA for now. The redbox is safely nestled on a shelf in my office at home. I removed it from a '94 Commemorative convertible. I'd be happy to sell it. I was planning to throw it on eBay since people apparently go nuts for these things, but I'd let it go on here for a cool hundred dollars, and I'll cover the shipping.

4 x 108 is very common in Europe, the issue for Saab's is the large 65.1mm center bore compared to the common Ford center of 63.3. Also the Saab offset is around 33-39mm depending on if you have 900 or 9000 wheels compared to Ford offset of around 48mm. The good news is you can use spacers to get around this and rely on lug centering rather than hub centric.

If you poke around you can find 15" and 16" Rota RB's with 4 x 108 and a 73mm center bore on e-bay, although that gets pricy.

I've bought some cheap Ford Cougar 16x6.5 wheels with snow tires to use for rally cross if I can ever get the car running again.

I've got a set of 15" x 7" BBS Bugatti wheels that were supposed to be an OE Saab fitment from the late 80's...Bought them off ebay and were supposed to be 15" x 5.5" for my former Fiesta. Similar to these, but 4 lug:

Yeah. Those were a dealer-installed option, IIRC. Personally, I'm partial to the Ronal cross spoke wheels. I managed to find a set for my convertible. They seem a lot lighter than the standard Saab offerings, but I didn't really care about that for this car.

A few years ago, I managed to pick up a set of 15x7 Team Dynamics Pro Race 1s that were made specifically for Saab fitment. I have to imagine that there are other sets of them floating around. Mine came from Canada.

I'm using 9000 sedan wheels with 205/55/15 Yokohamas on my c900. They are 15×6.5 and look like they belong on the car, and are lighter than aero wheels. There was also a 15×7 5 spoke wheel that were optional on 9000s. They are rare but they can be found.

Ojala wrote: A few spare transmissions?

There are SOME mods that can be done to extend the life of the SAAB/GM (yes GM) 5 speed manual transmission... One is a trans cooler/pump assembly, another is a directed oiling jet directed at the ring gear (ring and pinion failure pretty common - related to the main shaft bearing weakness)

I know that heat kills these transmissions. As half the case serves as the oilsump for the engine, I am sure it gets hotter than most manual boxes do.

While I had not considered a cooler.. I was going to add a transmission temp gage to watch how hot it gets. Maybe a cooler/pump with a manual switch might not be a bad idea?

Trans Oil pump and cooler along with absurdly frequent oil changes (like 3000 miles) help. A lot of guys geek out on chill cast trans cases and pinion housings. Steel pinion spacer, steel diff plate, external braces, and etc -you get the idea. Fantastic car and engine but the trans is the definite weak point.

well.. that trans was built for the 90.. which had a lot less HP than an SPG

About c900 gearboxes :

I really think the problem is exaggerated. I've owned 3 c900 turbos. I haven't babied any of them, and the worst gearbox problem that I have experienced was a shifting into reverse problem on a box with about 250k miles. I'm not saying that catastrophic failures don't happen, I've seen it happen to a friends carefully driven & well maintained 900 at 175k miles, and that was one of the supposedly really good early nineties boxes.

But IMO, a very large percentage of the failures come from abusive drivers* and/or highly modified engines with high mileage boxes. Weak and damaged front motor mounts lead to binding shift linkage, which in turn leads to damaged shift forks and synchros. Another thing to consider is that the gearbox was designed in the very early seventies for the 99, which was much lighter and had half the power. There were many revisions from the early 4 spd gear driven primary boxes to the later 5 spd chain driven primary boxes, but the basic architecture with its limitations didn't change. Fun fact: despite the fact that it has 5 speeds, the high gear is not an OD ratio, in fact I'm pretty sure that its not even a direct 1/1 ratio.

• driving techniques that you can get away with in other cars are abusive to c900 gearboxes. You can't slam gears and dump the clutch like its a mustang with a 4 spd toploader, you need to shift smooth and deliberately and not kick or dump the clutch. Once you learn the technique you can still drive very quickly.

A few years ago I did a 15.85 second pass at Cecil county raceway (with hard as rock tires, a pathetic RT and a malfunctioning boost controller) shifting the way I just described . That is a respectable time for a lightly modded c900.

Disclaimer : I am not a c900 gearbox expert, all the information that I just shared is well known in the c900 enthusiast community. If you want your mind blown go to saabrally.com forums and read some of the gearbox threads they have.

In reply to HappyAndy:

To be fair I wasn't close to stock power levels. Its just so easy to make power with that engine but the downside was that I got pretty good at rebuilding Saab transmissions.

About to change the oil in the trans. Any suggestions? I have heard everything from straight 10w30 to Honda MTL.

In reply to Powar: Do you have a way to accept payment by credit card? I have a gift card that would be a perfect source of funds for the red box.

I can't wait to see how the trans in my turbo shifts. It originally came out of my 91 2.1, I had it rebuilt even though it's only problem was a recalcitrant reverse.

ls1fiero wrote: In reply to Powar: Do you have a way to accept payment by credit card? I have a gift card that would be a perfect source of funds for the red box.

PayPal works for me. Send me a PM on here if you're interested.

Re: Gearbox failures. I've had exactly one failure in 13 years in the 13 C900s and 4 99s that I've owned. I don't run big power through them, but I also understand what I like to call 'mechanical sympathy'. It makes a big difference. The one trans that I did break was the one in my very first car. Burnouts, J-turns, e-brake slides, etc. It happened. I regret destroying a nice car, but it happened.

The one in my current 86 900 locks up going in reverse and wines going forward. I thing the pinion bearing is bad. This one has seen a hard life though it was my 2002,03,04 challenge car. 15 psi boost on 10:1 engine, My daughter learned to drive a stick in it. I have a spare trans waiting to go in, someday.