New here? You want more power? Read here FIRST.

DISCLAIMER: I did not force you to go out and get yourself in trouble while behind the wheel of your car after doing these things to it. Be careful when behind the wheel, do not let your friend drive once your Saab is transformed into a rocket ship after reading this information.




If you're here to any of the following questions:

"How do I get more power from my Saab?"
"Which turbo should I get?"
"How much horsepower will I make if.....?"

Keep reading.

For other questions, USE THE SEARCH FUNCTION BEFORE MAKING A NEW THREAD. More than likely, you will find the answer you are looking for.




If you've been on here for a while, you may have noticed that many of the same questions pop up over and over, so I'll try to be as transparent as I can in this thread with the different possibilities that await you and your newly found love. A lot of it is common knowledge but maybe not for some. People were there for me when I had questions, and since then, I've just tried to pay it forward as best as possible, so I hope this helps some of you who are new or even if you've been around a little while. Here goes.
Note that most of this applies to MANUAL transmission vehicles.


The Turbocharger

For those who are entirely new to engines, turbochargers and tuning, I highly recommend these links to begin. They are simple yet concise explanations to give you the basics.

How Engines Work - www.howstuffworks.com/engine.htm
How Turbochargers Work - auto.howstuffworks.com/turbo.htm

Generally speaking, the purpose of the turbocharger is to 'recycle' exhaust gases coming out of your engine, using them to spin a turbine wheel on one side of the turbocharger before exiting through your exhaust system. This turbine wheel is directly connected to another wheel via a shaft. The purpose of this second compressor wheel is to compress the air it intakes when spun at really high speeds. Compressed air means more dense, meaning more can fit into a space. This compressed air is then routed through the intercooler, cooled and fed into the throttle body.

In short: exhaust gas comes out of your engine, feeding into the turbo, spinning the turbine wheel and, in turn, spinning the compressor wheel, which compresses air allowing you to fit more of it into your motor. This, combined with the appropriate amount of fuel, makes more power. The larger the turbo and its exhaust/compressor wheels, the more exhaust/rpm it needs to reach peak 'boost'; thus, the rpm at which peak torque arrives is shifted to the right on the scale.


Now back to Saab.


If you've got the following model, then:



1994-1998 Saab 900 2.0 Turbo - Garrett T25
1999 Saab 9-3 - Garrett T25
185bhp - 2.0L B204L

1999 Saab 9-3 HOT - Garrett T25
200bhp - 2.0L B204R

1994-1998 Saab 9000 Aero 2.3 - Mitsubishi TD04-15T, 6cm^2 exhaust housing
225bhp -2.3L B234R


And in some markets,
1994-1998 Saab 900 2.0 Low-Pressure Turbo - Garrett T25
155bhp - 2.0L B204E (differs from a B204L - lack of Boost Controller (BPC) and different software)

T5 Engine Management - MAP sensor



2000-2002 Saab 9-3 Base - Garrett GT17
185bhp - 2.0L B205L

2000-2002 Saab 9-3 SE HOT - Mitsubishi TD04-15T, 5cm^2 exhaust housing
205bhp - 2.0L B205R

1999-2002 Saab 9-3 Viggen - Mitsubishi TD04-15T, 5cm^2 exhaust housing
225bhp - 2.3L B235R


And in some markets,
2000-2002 Saab 9-3 Base 2.0 Low-Pressure Turbo - Garrett T17
150bhp - 2.0L B205E (differs from a B205L - different software)

T7 Engine Management - MAF sensor


Yes, they're all interchangeable, and you can put a TD04-15T on your 1994-1998 900 or whatever you like, but we'll get to that. The flange on all these turbos is of the T25 designation, not to be confused with the actual Garrett T25 turbo.

Also, if you pop your hood and see a RED cartridge on the motor that says Direct Ignition, you have T5 engine management. If it is BLACK, you have T7. Do not interchange these cartridges with ones of a different colour.



But wait, first, can I run outside and stick a blow-off valve on my car?

Before I get going, I want to make it clear from the start because I know someone will ask.
YOU CAN NOT USE A BLOW-OFF VALVE ON T7 CARS. Period. For those T7 owners who want to upgrade from their fault stock bypass valve, Forge offers a nice aftermarket unit that recirculates back into the system as it should. There is no way around this today, but with further tinkering in T7suite, someone may come up with a trick.


BOOST DOES NOT EQUAL HORSEPOWER

One last thing I'd like to clarify before going is that it annoys me pretty bad when I hear it. If you're boosting 30psi on your stock T25 and your friend is only boosting 20psi on his GT3071, you are NOT making more power than your friend. xxPSI is an arbitrary number that tells you nothing without knowing what turbo it applies to. DO NOT embarrass yourself and possibly the Saab community by walking up to someone at a car show not knowing anything about the car and asking, "How much psi is it doing?"
You would be disowned if I were your mother.


Now the Stages
This hierarchy of staged tuning has been standard terminology for years, so we stick to them. Horsepower ratings are approximate and will vary by dyno, your Saab's health, specific modifications, etc. Even though this part of our forum is for all NG900 and OG9-3s, these mostly pertain to those without the TD04 but do not differ by much besides the turbo.


Stage 1
~220bhp/190whp
'Stage 1' ECU tune

It's as simple as that - your ECU gets remapped, making appropriate ignition timing and fueling adjustments.
Open air intakes and aftermarket air filters are OK, but one member has proven there to be no gain over the stock filters. That is fine if you want those things for the look/noise.

Stage 2
~240bhp/210whp
'Stage 2' ECU tune, 2.5" Catback exhaust

Not much to explain here. You have a larger exhaust for the turbo to breathe out of (imagine blowing through a straw as hard as you can), and it flows more unrestricted, allowing the turbo to spin easier.

Stage 3
~260-270bhp/230-240whp
'Stage 3' ECU tune, 3" turbo-back exhaust OR 3" downpipe mated to 2.5" exhaust, upgraded intercooler, stage 2 clutch disc and Viggen pressure plate (optional)

Instead of just a larger exhaust from the catalytic converter and back, ideally, you're replacing the whole system from the turbo on back to the muffler with a 3" system. This further loosens up the back pressure created by the smallish 2.25" stock system right at the turbo allowing it to spool slightly faster but more importantly lower Exhaust Gas Temperature (EGT). Genuine Saab offers a very reasonably priced full 3" turbo back system for a similar price that many would want for just the downpipe, which is why it gets my recommendation. Mine has held up just fine for over five years. You can also make your downpipe and exhaust for very cheap. If you have an excellent cutter, a few well-chosen 3" bends, and a welder (or a friend with a welder), you can spend less than $100 for a nice downpipe.

As for the intercooler, many people like to upgrade to the 'Viggen intercooler,' which can be found on either the B204R or the B235R. Due to the high cost of one, I would highly recommend searching for one on eBay or, if you have the money, purchasing the ETS intercooler, which is more drop-in. For those looking on eBay, 28x8x3.5" dimensions of the absolute most oversized intercooler you can use, including the end tanks. An intercooler is not necessarily required at this level, BUT if you use the stock NG900 unit, heat soak will be very noticeable, and you probably won't be able to go more than two gears worth of WOT pulls before you feel the power fade. Also, a cooler charge temperature means you are much less susceptible to knock, which is a good enough reason. A Viggen intercooler is slightly better than the NG900 one, but not by too much.

Your original clutch may also start to slip at this point, depending on how it has been treated, so if it does, now is the time to upgrade. The stage 2 Clutchnet disc offered by GS is excellent for daily use and similar to the stock feel. Stage 3 is a little more aggressive but not impossible to deal with. I had a set of 3 discs last for about 60k miles which included 30+ pulls on the drag strip and COUNTLESS runs while tuning. I'm now using stage 2, as recommended to me.


Stage 4
~285-295bhp/250-260whp
3" turbo back exhaust, upgraded intercooler, TD04-15T 5cm^2 or 6cm^2 housing.

The difference between stages 3 and 4 is the turbo. If the Mitsubishi is the turbo you already have on your car, then this is where the hierarchy merges. The TD04 is just slightly more significant than the T25, but even so, you will need a retune if you are coming from stages 1-3 because your new turbo will be flowing slightly more air.


From this point on, the stages are slightly less defined due to the number of different paths you can take. They refer more to the power level than the actual hardware, but because we don't want to remember 20 different stages, I will group them as best as I can based on this. It is not necessary to stick to them, though. I also won't drag out too much detail at this point because if you're at this level, you probably need to be doing a little more research for info that my little thread won't give you. : nono;

You should also consider a custom, in-person tune as a requirement beyond this point.


Stage 5
325-395bhp/285-350whp
3" turbo back exhaust, upgraded intercooler, 3 bar MAP sensor, Custom tune, T28 OR GT28rs (Disco Potato) OR GT2871 OR TD04-18T OR TD04-19T, Walbro 255lph fuel pump, Siemens 60# or 80# injectors, Pistons (T7 cars required)

For those looking for a lot more pep in their step, this is where things get fun. I have seen all kinds of power numbers with the T28. The TD04-18T - in my opinion, you're better off getting the 19T because the difference in lag between the two is negligible. With the 19T, a personal friend of mine has made 320whp. The GT2871 probably surpasses them all in terms of power - I believe Nick at GS made closer to 400whp with one.

For those of you with T7 motors: your engines will not hold up much past 300whp. It may last for a while, but you are eventually doomed. To reach this level and beyond, it is necessary to build the motor.

For fueling, I put the Walbro because it's cheap enough of an investment (~$100) and if you want E85, you're gonna need it anyway. The Siemens injectors are available in 60lbs/hr or 80lbs/hr. Again, my recommendation is just to get the 80lbs/hr ones because the price difference is so slight and because you don't want to 'under-injector' yourself if you decide in the future to make some changes.

A 3-bar MAP is only required if you expect to be boosted more than what the stock 2.5bar MAP sensor can read. 1 bar is 14.7psi. Accounting for 1 bar of atmospheric pressure, a 2.5bar MAP sensor can thus read 1.5bar of boost, which is 22psi. If you are going to be above this, upgrade your MAP sensor.


Stage X
400bhp-700bhp and beyond.
3"/3.5" turbo-back exhaust, upgraded intercooler, sufficient fueling, pistons, rods, larger camshafts, valve springs, larger turbo, tubular manifold, external wastegate, etc.

I think you get the idea by this point. There's always more you can do. Enem camshafts for better intake and exhaust of gases from the combustion chamber along with uprated valve springs, allow the motor to breathe better and be better suited for whatever large turbo you decide to stick on it. Holset HX35, Holset WH1C, Garrett GT3071, GTX3071, GT3076, GTX3076, and the Holset Super 40 are all tried and true for our motors. 600whp is a number to remember - a stock B204L engine has been proven capable of holding up to this amount of abuse when tuned correctly. Many of you will not reach this point, but the upside to that is most of you can go without 'building' your motor unless so desired.

The nice thing about the Garrett ballbearing turbochargers is that they are available with a T25 flange, thus, will bolt up to your original manifold. The downside is the higher cost. However, there is a Garrett to fit whatever your horsepower needs are, so research them and find the one that is right for you. Dyno charts are floating around everywhere.

The Holset turbos are much cheaper, but for the NG900/OG9-3, you must purchase or have made some tubular manifold with a matching flange (divided T3 or T4 depending on your selection). A known version of the Holset HX35 comes from a 94-02 (or around there) Dodge Ram Turbodiesel Cummins engine. Very cheap to find on diesel forums and will make close to 500whp on E85, quick spooling when matched to a twin-scroll manifold. The Holset Super 40 is a high-performance Holset that has made over 600whp for some people. You don't need my advice if you're at that point.




The tuning

For the tune, no tune will work for any range of turbos. In other words, get a custom tune once you go beyond stage 3 or 4.. Each turbo has different spooling characteristics; thus, different fueling needs at different rpm and pressure ratios. Thus, you are better off allowing someone with experience to tune your car in person using proper instrumentation. It is worth it for safety's sake and to get the most out of your setup. If you're up to the task, you may join the ECU project to learn how to tune your ECU. Much easier said than done, but it is not rocket science. T5Suite for T5 ECUs, T7Suite for T7 ECUs. No, you cannot swap a T7 ECU with a T5 one.

My recommendation for tuning from being on these forums for a few years now and after learning T5Suite myself? Anyone who can make power gradually without just spiking the torque ASAP, who does not blow up engines, and who knows what they're doing. Base your decision on facts, data and experience. Just because a customer is happy that their car is faster does not necessarily mean the tune is a good one, so do some research before choosing. It's straightforward to max out on torque and roast the front tires in 5th gear, but what good does that do for acceleration? None.
Feel free to contact me via PM for more specifics.




More on large turbochargers - are they right for you?

The issue (notice I didn't say problem or disadvantage) of a larger turbo is the lag mentioned above associated with them. However, once spooled, it will reach and maintain a higher flow rate over a more extensive registry (rpm range). But in stock form, the B204/B234 engines can only rev so high - somewhere in the neighbourhood of 7000rpm - so you may get cut off before your turbo makes power. Stock camshafts are also a bottleneck as they are not meant to breathe in the upper rev range and begin to choke in those bounds. The way to overcome these things is to upgrade valve springs and camshafts to take advantage of where the turbocharger flows most efficiently. Revving to 8500rpm and beyond is not unheard of at this point, and you are thus only limited to the turbo you decide to use.


"But turbo lag! I've watched YouTube videos, and my friend's car doesn't spool til 4k! That isn't practical!"

This is a common misconception, in my opinion. I have driven my car daily for three years now with a turbo that reaches has the potential to achieve full boost at around 4100rpm. One thing you notice when you go up in size is that the gas pedal is no longer annoying the On/Off switch of torque. In other words, it's excellent for commuting around town. In everyday driving, 80% of the time, you won't be driving at wide-open throttle, so a high amount of torque isn't necessary for the expected rpm range. But if you get an itch and want to go fast, it's as simple as a downshift away. For those who race regularly, lag in first gear is the only lag you will have to overcome, given you are shifting properly.

As a bonus, better gas mileage is more easily attained, and you may also find yourself just enjoying the drive for once rather than feeling on edge just as the peaky stock turbo would.


T7 Boost Pressure Control Valve (BPC) for T5 cars

This is an upgrade that I highly recommend for those with T5 cars who either already have a faulty boost controller that needs to be replaced or who want more reliable control. The newer one is a much better design, and if it does happen to go out, they can be had for a low cost. They are incredibly cheap, especially compared to the T5 unit, and only require some easy rewiring to the harness and an adjustment to two different numbers within T5suite. This is not necessary at any level, but it's just nice not to worry about the crappy stock one. Search the forum for the How-Tos.


Suspension

Do NOT forget your suspension modifications. Believe me when I say much over 400lb. Ft. of torque is USELESS on the road if the chassis is not up to the task of holding the tires on the ground. I'm not covering suspension much in this thread, but do some research on your own and don't neglect it. Going much over 100mph in these cars on stock suspension is pretty scary. Let alone 150mph (on a track, of course).


Other nice things to have

There's always more you can buy. Nothing is set in stone.

Silicone vacuum lines - are much more durable than rubber ones; go to your favourite vendor and order enough to replace them.
Boost gauge - These cars come with a factory 'gauge' on the cluster, but it's more fun to watch than anything. There are many good brands, be sure to find one that reads up to 30psi, just in case.
Methanol Injection - Spray a methanol solution into your charge pipes, and cool the charge temps to make more power and run more safely. There are many DIY guides online; Snow Performance sells kits, too.
Uprated engine/transmission mounts - To my knowledge, Genuine Saab is the only place that makes one for us. Very worthwhile to keep everything in place once you start beating on the car.
LSD - Traction and drive are greatly improved. Pricey and should be done by specialists only
Tires - If you're really into stoplight showdowns, a good set of tires is a must. More sticky tires will also wear faster because they are softer - a treadwear rating between 100 and 200 will be noticeably more humid than a treadwear rating of 400. Still, they will also last 1/4 and 1/2 as long, respectively.
E85 - Use ONLY if you are tuned for it or if you have a separate ECU that is tuned for it for your car. With larger turbochargers, you can expect to gain at least 40whp-50whp. I'm not sure what the potential is for stages 1-3, but there almost certainly are some.




Most of all, be safe. And be sure to change your oil at regular intervals!


-Branden