Frequently Asked Questions


What are the differences between the Viggen and the regular Saab 9-3?
This image by Saab shows the main differences nicely.
But in reality, you have to drive both cars to know the difference. I test drove a 9-3 Aero a few days before the Viggen. The difference was night and day, much more than the 20 hp difference might suggest. The Viggen is pure brutal power. If you are able to handle it, it is sheer driving pleasure.

Who designed the Viggen?
The Viggen is based on the Saab 9-3, and the Saab 9-3 is based on the Saab 900-II ("GM900"). The initial draft of the GM900 was made on 24th of july 1988, some years before Saab was bought by GM, by Björn Envall. Björn Envall was a pupil of Sixten Sason, who designed all Saab cars from the Saab 92 up to the Saab 99.
The Viggen Body kit was designed by Ian Callum, of Aston Martin DB7 and Vantage fame. He was manager of TWR, the company behind the Viggen. He later became head desinger of Jaguar and is responsible for the very successful Jaguar S-Type.

How often should I change the oil and which oil should I use?
If you ask most Saab dealers, they will tell you that an oil change every 20.000 km is ok and that you should use Mobil One 0W40 fully synthetic oil. While I partly agree with the second part, I think the first advice is rather dangerous. If you drive your Viggen like most Viggens are driven (i.e. hard), change your oil all 10.000 km. It might safe you from an engine failure and is not that expensive.
More difficult to answer is the second question. The majority says you should use a fully synthetic oil like Mobil One. Heuschmid however thinks this is not good in every case. Under very high load or much city driving, the fully synthetic oil will sweat out water, which will reduce the lubrication effect of the oil and harm the engine. He thinks you should chose a good semi-sythetic oil (he prefers Shell 10W40) and change it every 10.000 km. Semi-synthetic oil is cheaper, too. I am following his advice.
UPDATE 09.09.09: Since I have an engine with forged pistons (june 2008), I found out that oil consumption is lower using fully synthetic Mobil One 0W40.

Is it a good idea to change the stock air filter to a performance air filter?
Most Swedish tuners think it is. Hirsch doesn´t think so. The reasons:
- The high performance air filter will only flow better than the stock Saab paper filter if freshly cleaned.
- The oil used on the performance air filter will settle on the Mass Air Flow (MAF) Sensor which is mounted at the air box outlet and will cause missreadings or even a MAF failure.
I kept my performance airfilter, but not because I think it really causes a higher performance but because I like the induction noise, which is much louder than unsing the stock airfliter. However, I try to use very little oil after cleaning the airfilter, and I sometimes clean the MAF with isopropanol.
So far, after more than one year with the JR performance air filter, my MAF is still alive.
UPDATE 09.09.09: I'm using JR filters now for many years without problems. But remember to clean them quite often, it is surprising how quick they get clogged.

How do I clean the mass-airflow-sensor (MAF)?
Sometimes, dirt (or oil from a performance air filter) will settle on the MAF which is mounted at the air box outlet and will cause missreadings. If you notice any problems with boost, it might be a good idea to clean the MAF.
This is how the cleaning is performed (thanks to Ollin Ruosaari for the advice): Buy some isopropanol spray (they often sell it where they sell electronic parts like resistors, LEDs, etc.). Remove your MAF. Once you have removed it, you will see a netting and behind that a few wires that run across the flow area. Aim the spray at these wires. Once done, allow the isopropanol to evaporate. You can use a hair dryer for approx. 10 minutes to make sure that the unit is dry. Remember to reset your ECU, otherwise it won´t be able to adjust to the new settings. You can do this by removing the battery cable for 15 minutes. Re-calibrate the ECU once the car is restarted.

Why should I change the spark plugs when tuning the Viggen to higher hp levels?
Trionic 7 uses the spark plugs for knock detection. The stock platinum spark plugs, used on the Viggen mainly for longer service intervalls, are suspected to detect knocking at higher rpm even when there isn´t any, which causes the ECU to take back ignition an boost, thus not allowing to reach maximum power. The regular spark plugs are much cheaper than the platinum plugs, so it is no problem to change them every 10.000 km.

I drive a MY99 (225hp) Viggen. Why should I change the intake pipe when tuning the Viggen to higher hp levels?
The MY99 intake pipe from airbox to turbo is very restrictive. You can see this on the right side of the picture: The pipe does not use the whole diameter of the connector to the turbo inlet. This was changed in the second MY of the Viggen (i.e. 2000) and was one of the reasons the engine delivered 230 hp from now on. Hirsch recommends to replace it with the less restrictive MY2000 pipe, which is quite cheap. If you aim for even higher hp numbers, you should choose a custom made intake pipe, as the pipe offered by Hirsch.
Be aware that on most MY99 Viggens, some water and oil pipes have to be slightly moved to the fit the custom pipe. This is quite a hassle and I didn´t consider it worth the work. However, if I ever should have to change the turbo charger, I will also change to the big pipe.

Why is the Viggen more prone to engine failure (cracked pistons, damaged cylinder walls) than the 9-5 Aero with the same engine?
1. Temperature! The Viggen has less space under the bonnet. This forced Saab to use a different intake and exhaust geometry. Plus the Viggen IC is in fact not as good as the 9-5 ic. Under certain conditions, the b235r intake temperatures are more than 15°C higher on the Viggen than on the 9-5 aero. Heat is your enemy! Higher intake temperatures -> higher egt (exhaust gas temperature) -> more strain on the engine)
2. Driving style. The Viggen is more often raced than the 9-5 Aero.

Then, why not install forged pistons instead of the stock pistons?
When I had massive oil consumption on my Viggen, this was attributed to blown pistons (this was not entirely right, but more later). As I had to spend quite some money, I investigated if forged pistons could be the way to go. A german tuner offered to install Wiseco custom forged pistons, but he told me that usually, 50.000 km on forged pistons would be a lot. It is not the piston that fails in this case, but the cylinder wall. This was backed up by a Wiseco rep I phoned: Forged pistons behave different from standard pistons concerning heat. If the car is still cold, piston tolerance is bigger. This will cause additional horizontal movement on the piston and therefore more wear on the engine. Not good for people using the car for a lot of short trips / city cruising.
Plus, if the piston is very hot, it can "mill out" the piston wall, which is softer than the piston material.
Generally speaking, one could probably say that the thermic balance of the engine is "disturbed" by using a forged piston, as the engine block was not designed to work with such a piston in mind.
The same was explained to me by Johann Heuschmid, former Saab factory tuner, and a Mahle Rep (Mahle is a South-German company which makes the stock pistons for the B235R).
UPDATE 09.09.09: I'm using a MapTun engine with forged pistons for more than a year now for both daily driving and the race track. The engine has covered 20.000 km so far, without any problems.

What is the limit for the Viggen´s pistons?
There are rumors on the internet that B235R pistons are weak and only good for up to 300 hp. This is also believed to be the reason why Hirsch limit their cars to 305-310 hp. However, there are a few B235R cars out the with far more power, running fine for quite some time now. I.e. Hirsch´s own Tuner GP car with 324 hp and Ollin Ruosaaris Viggen with more than 340hp.
To cite Ollin: Generally speaking, what will work for one will not work for the other. For instance one Hirsch employee wrote on the swedish Saab board that they ran a B235R engine up to 400hp with out failure, but at the same time there are people who have had failures with standard power levels. What does this tell us?
There are other variables within the B235R construction besides the physical piston itself that will lead to the "known" failure. Is the B235R more vulnerable to piston failure with 350hp than 250hp? We know the both can fail. Out of all the tuned B235 piston failures how many would have broken anyways? WE DO NOT KNOW.
What are some of the most common problems faced by T7 cars?
1. Weak and failing oil pumps that can drop to dangerous pressure levels before any warning light ever appears. This has been shown to be independant of sludge and clean engines have failed from oil starvation despite not having a sludge issue.
The pistons are cooled by oil squirters. If the oil pressure is much much lower than it is logical to assume the pistons are not having as much oil squirted on them and this reduces the cooling they would normally benefit from.
2. Faulty PCV systems
The PCV system failures have shown to cause an increase in blow by as well as overpressurization of the crankcase. This can lead to sludging which can also lead to oil starvation, low oil pressure and see point above. Another issue this creates is that oil (not just fumes) is sucked into the intake stream to be combusted. How many people have seen intercoolers caked with oil? Oil in your air/fuel mixture will rob the fuel of it's octane and we all know how important octane is (-knocking).
3. Mass air flow sensors commonly fail or at least show to have inaccurate or inconsistant readings
The differences between T5 and T7 are many but the most important is the method of fueling calculation. I won't get into the specifics but with the readings of the MAF sensor being so critical to T7 fueling, it could be that this simple part plays a large roll in knock if the part is not functioning correctly.
4. Direct Ignition Cassettes or IDM (could be the most common and well known problem with T7 cars)
Can the ECU accurately sense knock if the IDM is failing? Many have said there were issues that were suddenly fixed when the IDM was replaced. The old view that these parts simply worked or did not work is no longer accepted. Just because your car starts and runs does not mean the IDM is working at 100%. If the ECU can not "hear" the knocking, how does it know to cut back on power?
I'm sure there are other factors. I think it's more the systems in place than just the size of the pistons that is causing these failures ("The newer and less robust pistons failed because the oil pressure was so low it caused the pistons to overheat which combined with a non-functioning PCV system to increase blow by and oil in the intake which reduced the octane and caused knock which could not be detected because the direct ignition cassette was not functioning properly.").

So are the B235R pistons really "weak"?
I already promised to talk about my specific engine problem. I had a 1999 B235R in my Viggen. This was the first MY for the B235R, and therefore not quite free of flaws. While the pistons where in fact more solid than the MY2000 pistons, whose piston rings where mounted "too high" for emission reasons, it was to soft cylinder walls that were the problem. What happened to my engine was quite similar to what can happen with forged pistons: The pistons, when very hot, milled out the cylinder walls (stock pistons in the b235r are coated and quite hard, too), therefore causing too much piston tolerance -> oil consumption.
Solution:
-Change oil often.
-Try to keep egt low. How? Good IC, not too much boost. If you are a true Trionic genius, you can get much power on less boost.

Example:
When software re-calibration at Hirsch Performance was finished, my car pushed more hp on base boost than a stock Viggen on full boost.
By gently raising boost, Tommy Utengen created a very smooth torque curve, having less strain on engine, transmission an gearbox. Boost never raises above 1 bar.
When using my Maptun Stage III software on exactly the same hardware setup, max boost is around 1.4 bar (on hot days). This results in a little more power on the way up the rev range (until 4000 rpm), but much more strain on engine, transmission and gearbox. Because max hp is limited by the turbocharger, max boost at 5000 rpm is always around 0.8 bar, independantly of the software used. So max power should be about the same for both programs (in reality, around 5% more max power is reached using the Hirsch software).

When using the Hirsch custom software, EGT hardly ever goes beyond 910 °C, the car runs very, very healthy (Air fuel ratio, lambda, ignition, no knocking, low egt, no ic heat soak, nearly no turbo lag).

If you manage to keep temperature low and oil flowing, the pistons should be perfectly happy. They are not bad after all. They are just not as over engineered as the b234r pistons (9000 Aero), thus allowing smoother revving, lower emmisson, lower fuel consumption. It´s all a question of the perspective.

What is the limit of the Viggen´s turbocharger?
The Viggen´s stock turbocharger is a Mitsubishi TD04-HL15T with a 5cm^2 exhaust part. It is good for about 280 hp. If you spin it even faster, the charge air will be very hot -> not good for your engine, but short bursts up to 300 hp are possible this way.
N.B. The 9000 Aero uses a TD04-HL15T with a 6cm^2 exhaust part. This turbo will deliver 300 hp without overheating. The smaller exhaust part on the Viggen was used for a better low end, but I´ve heard that the Aero´s exhaust part should be a straight swap.

What is the limit of the Viggen´s injectors?
The stock injectors at stock fuel pressure (3bar) are good for around 280-290 hp if the ECU is fine tuned. The Hirsch 9-5 Troll delivers 305 hp on stock injectors, but using a 3.5 bar fuel pressure regulator (as does the Nordic Stage III Kit for the 9-5 Aero). Fuel pressure can also be raised to 4 bar, but for applications beyond 320 hp, bigger injectors have to be used.

The difficulties of Trionic 7 tuning, compared to Trionic 5.
The Trionic 5 system is a pure pressure related system, it only uses the boost in mbar and the intake air temperature to adjust slightly. No corrections take place in boost level, so if the ECU is programmed for a target boost of 2000mbar (absolute) at a certain rpm, the ECU will control the PWM (pulse width modulation) up to this boost (if reachable). There is no boost adaptation at all.
The Trionic 7 system is a pure airflow (mass) related system, boost (mbar) is not used (only for backup functions). (The only systems known to me using both (airflow and pressure) are Bosch ME7 and 9). Therefore the boost pressure cannot be specified and changes everyday, depending on atmospheric pressure and on intake temperature (hotter=more boost). So if you start in the morning with an intake temperature of 40°C, the requested airmass say 1000mg/comb (milligrams per combustion), you could have say 1900 mbar boost (abs). After driving a while in the traffic, the intake temp might raise to 60°C and the boost goes up to 2000 mbar on still 1000 mg/comb. Lower density of the air is corrected by the higher boost. However, this doesn´t mean that you get out the same power!
Hotter air is more knock sensitive (less efficient), the VE (volumetric efficency, basically the filling rate of a cylinder) is lower (due to the increased duty cycle of the turbo) and the ignition is reduced. These are basic functions.
The adaptions, boost or fuel are not very "long term". In fact, they are adjusted all the time, constantly when you drive in the "adaption windows". The boost adaption is not really power affecting. On steady load, the PID (Proportional-Integral-Derivative control) will take care of any kind of positive or negative adaption on boost. So the power result is not affected. But on transients (short acceleration) you "feel" it: Negative adaption will cause that you never reach the target boost in the short term (it is used to prevent "overshoothing" the request).
The fuel adaption (mult) however is affecting the power output. Now, if you have a car that runs "lean" in the closed loop (the lambda integrator has to add fuel to get lambda 1), you will have a positive fuel adaption. This % value of added fuel will be added on the request in the open loop (out of lambda control). Richer mixture = lower output.
Here lies the reason why upgrading of hardware parts without adjusting the software will most likely lead to some form of misbehaviour within Trionic 7 (this can be loss of smooth power, ability to adapt to different situations, etc) instead of a real gain of performance - a higher peak hp is not preferable if it affects T7’s smoothness of power delivery and ability to adapt to different situations:
The system is programmed to give a "fixed" fuel amount depending on rpm's and airmass ("fuel maps"). The airmass is a value coming from the original (initial) calibration of the Airmassmeter. If you change a hardware part (airfilter, exhaust, etc.) you affect this calibration, therefore the measured value is not "correct" anymore (1 is not = 1 but perhaps 0.99 or 1.01 or whatever). So the lambdaintegrator will need to adjust the lambda 1 factor back (adding or subtracting) and therefore you have a fuel adaption.
Hardware changes have enormous impact on the MAF calibration.
The first step any good Trionic 7 tuner should perform after upgrading hardware parts is a full recalibration. This can be done on a dyno and takes some hours work because of the sheer number of maps.
Also one should keep in mind that once you change one hardware part of the car to a custom piece you will be in this mess forever if you don´t have the possibility to custom tune the software: If in future you might decide to tune your car to a higher level, no "stage" software will mix with the custom hardware part.
So there are only two sensible options with Trionic 7 cars: Buy a complete stage kit with adjusted software included or take your car to a custom ECU tuner after all hardware changes have been made.
(Original text by Ollin Ruosaari)

300 hp should be doable with the mods you have. Nordic pulled out 306bhp from a 9-5 aero with less mods.
Tommy was very explicit about what he thought of that. He thinks that most tuners just do the software on their PC, install it on the ECU, drive to the dyno, take the best peak run and don´t care about stable long time performance. He said it would be absolutely impossible that Nordic reaches more than 300 healthy hp, while he, with 13 years experience in Trionic developement, does not.
Don´t get me wrong: He thinks that my car will dyno +300 hp near sea level, too. But stable performance for the stock injectors and the Viggen style TD04HL-15T is somewhere around 280 hp - and I will have those now under nearly all heat, load and height conditions.
Update: I know one 9-5 Aero owner with said Nordic stage 3 software. On multiple dyno runs, it never dynoed more than 270 instead of the promised 300 hp.
N.B. Nordic - like Hirsch - have their own dyno facility.

How to improve the Viggen brakes?
a. The standard Viggen brakes are pretty good. They are based on the same calipers and pads as the regular Saab 9-3 brakes. However, the Viggen uses different caliper carriers, moving the caliper further from the hub. This makes it possible to accomodate larger (308mm) front discs (stock front discs are 288 mm). The larger discs have two advantages: They dissipate heat better and by moving the caliper further from the center of the brake disc, greater brake torque is achieved (The brake caliper acts on the disc at a certain distance from the hub centre, known as the effective radius. The force exerted by the caliper, multiplied by the effective radius of the system equals the brake torque. Increasing the effective radius results in increased brake torque).
Both the 308 mm front discs and the 286 mm (same size as stock 9-3) rear discs are grooved and ventilated.
The Viggen also has a greater capacity brake servo master cylinder.
b. You can improve the brake performance easily by replacing the stock front pads with Ferrodo DS 2500 brake pads. Stopping power will increase, but so will wear. Using the Ferrodo pads, brake performance will be satisfying for the occasional track day.
Warning! Make sure to check the brake pads on a regular basis (don´t forget the inner pads!). Ferrodos wear down quickly. Look what happened to me after less than 20.000 km...
c. An inexpensive upgrade for a mainly roadgoing car are the 314mm 9-3 SS Aero discs. Speedparts offers a set including (small) Brembo 4-piston calipers for a very good price. Those should provide better stopping power, acceptable running costs and troublefree operation.
UPDATE. I´ve seen this system installed on a NG900, and I was not impressed. The small Brembo caliper does not use the entire contact area of the disc, so the inner area will not wear and probably rust. Also, the vented disc is designed to suck in the air form the outer side - where most of the air is sucked away by the wheels. It would be better to take the air from the inside, like the Porsche disc does.
d. A good, but very expensive brake upgrade for a mainly roadgoing car is the system offered by Hirsch. It includes 332mm discs and medium size Brembo 4-piston calipers. Big disadvantage are the very high running costs (expensive Hirsch discs and Ferrodo Pads). For frequent track and race use, the discs are too thin (only 28mm) and the contact area of the caliper is too narrow (less than 50mm), but the system is usually nearly free of annoying squealing or vibration. Also, every Saab dealership should be able to install and service them and get spare parts.
When used very hard, the single piece discs sometimes deform, causing vibration while breaking. Also, some squealing Hirsch brakes have been reported lately.
e. If you plan to participate in trackdays frequently, a brake upgrade including large discs and 4-piston-calipers is a worthwile investment. Brake upgrades for the Viggen are offered by MovIt, Nordic, Abbott, etc. You can also get Porsche brakes custom fitted, as I did. Disadvantage of all the big brake kits, compared to the stock brakes, are much higher running costs (disc prices between slightly less than 200 EURO per disc for Porsche 322x32mm discs and more than 300 EURO per disc for the AP racing discs supplied by Abbott, and a set of pads can easily cost 200 EURO). Also, those performance brakes are much more likely to squeal if only used for daily driving.
Here, I try to compare the different possibilities of designing a 4-piston-brake for the 9-3.

The perfect tire choice
The tires are the interface between car and street. Therefore, before modifying anything else, choose the right tire! Keep away from cheap no name tires.
Dunlop SP9000s have been proven to be excellent allround-tires for the Viggen in the dimensions 215/45 R17. They are both comfortable, grippy and avoid tramlining. In summer 2005, I used Yokohama AVS sport (225/40 R18) which offer, once properly warmed up, tremendous grip. However, they have very stiff sidewalls, tramlining is very strong and annoying and comfort is abyssmal. Next summer, I will try Dunlop SP 9000s in 225/40 R18 for street use and Yokohama A032Rs in 225/45 R17, which are racing tires, for race track use. I heard good things about Bridgestone Pole Position an Michelin Pilot tires, too. Just keep in mind that a street tire has to have a soft sidewall to avoid tramlining.
UPDATE: For track use, the A032R proved to be excellent. Grip is unbelievable. Nearly no tire spin, even in second gear. Big recommendation (but for every day street use much too loud).
UPDATE 09.09.09: I drive a set of Hankook V12 Evo for 5 months now, and I am very happy with them. I see no disadvantages compared to the Dunlop SP 9000. However, on the race track, they are no match for real race tires like Yokohama A032Rs.

Some additional tips and tricks
1. Buy some lowering spring like those made by H&R, Eibach, Hirsch. This will improve the ride of your Viggen tremendously. You don´t need new shocks, the stock Viggen shocks (made by Sachs) will do just fine.
2. If the Brake-Warning shows up in your cockpit, top up the braking fluid as much as possible. This will normally solve the problem.
(To be continued)
© 2005 - Philip Schneider Design - Chris Deutsch