Better Acceleration? [Archive] - SaabCentral Forums

: Better Acceleration?

14th May 2003, 04:36 PM
Hey guys, I'm new around here.

I got a "hand-me-down" car from my aunt in the form of an '87 Saab 9000 T. This is probably only a temporary car, until I can afford something else. Though, I do like the car considering it was free. One thing I am wondering is how to get some better acceleration out of this thing? The spool up the turbo takes a while.... and even 4 cyl. Toyota Camryy beat me off the line.

Any low cost mods I can do, or maybe some tweaking? (Take in mind I am novice when it comes to Saabs.)


14th May 2003, 05:36 PM
Welcome Inferno21,

Well a Toyota shouldn't beat you from the lights (although Saabs are not great from the lights) so I would suggest that you check that things are running correctly first. Check or replace the spark plugs, the air filter and inspect all of the rubber vacuum hoses carefully for air leaks.

How much boost are you getting on the turbo gauge? The needle should go quite close to the start of the red section under hard acceleration. If not then you should check and adjust the wastegate.

If all of this seems okay then you can start tweaking the car for more power! The first step is to modify the APC to allow the car to give more boost. It involves changing a couple of resistors in the APC box. I would suggest that you search the 900 performance section of this forum for information on this since the APCs on 900s and early 9000s are basically the same. With this mod alone you can see an extra 30 Bhp for no more than $1. Give it a try!


14th May 2003, 05:49 PM
Thanks for the info!

The Turbo gauge doesnt quite go to the spot you mentioned... so I'm going to have to take a look at that.

As for the APC mod... wow. I'll head over to the 900 section right now. :)

I found a fuse in the box labeled "speed control". Could this have any real world effect on performance, or do you know what the fuse engages/disengages?

15th May 2003, 04:30 AM
No, I think that fuse relates to the cruise control.

You first need to locate the APC box (it will have 'APC' on it). On early 9000s I'm afraid that I'm not sure where it is located. Possibly under one of the seats or maybe behind the false bulkhead. The box is black, about 5 inches by 4 inches and is connected to a large plug. Unplug it and undo the four screws holding the unit together.

You will see three pots: P, K and F. Don't touch 'K' as this relates to knock protection. I see that Keith on the Perf. 900 forum has provided you with the link to Tweaker's site. Just follow the instructions regarding swapping the resistors and adjusting the P and F pots. Don't be scared about doing this. It's not difficult. The result is a BIG difference in performance and it is quite safe (since full knock protection has been left intact).


15th May 2003, 10:04 PM
Where can I pick these resistors up in the U.S., anyone know?

Also... I cant seem to find the APC box. If someone knows where its located tell me!

16th May 2003, 11:05 AM
I am sure you can get the resitors at any Radio Shack...

17th May 2003, 12:27 PM
How's the performance now, did you find the culprit? It seems that you're only getting the base boost, and if that's the case, you will REALLY feel the difference when getting the full boost. Oh, and with a -87 9000 turbo you should go 0-60mph at about 9 seconds, which a Camry owner can only dream of...


17th May 2003, 04:12 PM
Well, the turbo is hitting right above the beginning of the red, where it should be. (According to others.) I hunted down the APC box, and found it. But ofcourse, its attached to the underside of the dash by allen screws, and I dont have a big enough allen wrench for it.

When I do try and floor it, a yellow light pops up on the dash, it looks almost like a box 2 dashed lines coming out of it. I have no clue what this is, perhaps the TCS kicking in? Next step is to clean out the air filter.... and we'll see.

17th May 2003, 04:23 PM
-87 9k T having a TCS? Hmmm...Not sure about that one. The yellow light you mentioned could be something as simple as the washer fluid reservoir warning light(my -92 9000T gives that light under acceleration when the reservoir is getting close to empty).

Well, you really could try to get the boost pressure measured with a decent gauge (pretty simple, just put a t-joint in the pipe line for the gauge), because if you are getting the turbo/APC needle close/next to the red (and not cutting back immediately), you really SHOULD be moving relatively quick, unless you're normally driving a Viper or a Corvette...


17th May 2003, 04:38 PM
OK, a really simple question, but I just have to ask. Do your rev's go up when flooring the pedal but you are not accelerating accordingly? If so, you are having a classic case of clutch slippage...This should also be followed by distinct smell of a burnt clutch.

My general advice is, check the simple things first (like fuel quality, plugs, filters) before messing up with details.


17th May 2003, 04:39 PM
It "chirps" if I am already doing 20 MPH... but it doesnt even come close to squealing the tires to the least from a dead stop. I'm not saying it should squeal the tires... but compared to my dads V6 Buick lesabre, and even my moms v6 minivan... the thing is a turtle off the line. And that minivan is pretty big/heavy.

17th May 2003, 04:49 PM
Okay then, this is instead of a classic clutch slippage, a classic case of a turbo lag...Just try to keep the revs above 2000 RPM, and you find your Saab pretty fast (just try and then try again and learn...). If it's an auto, it can feel even more lame from dead stop than a manual. Whether the car is an auto or a manual transmission, my advice is to minimize the "drag race" starts from dead stop and your tranny will live longer :roll:


Castor Troy
20th May 2003, 12:07 AM
hehe, my grandma's 91 9kt w/a 5speed(converted from auto) will leave 75ft rubber marks on pavement :D