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Discussion Starter #1
Last week I've been to Hirsch Performance in Switzerland to get a custom remap for my NG900. A lot of hardware has been upgraded on the car, so the software had to be changed to match the car, especially after installing a Mitsubishi TD04 turbo. The stage 1 chip I had is designed for stock 900 turbo models.

The turbo is a TD04HL-15T-5. This is the unit that's used on a 9-3 Viggen and 9-5 Aero. The TD04HL-15T-6 that's used on the 9000 Aero is capable of more power at the expense of early spoolup. Given the limitations of the NG900 chassis I thought it would be better to go for quicker spoolup rather than maximum power.

For Renato Boldrini, the ECU developer at Hirsch Performance, it was very important to get a nice and smooth power delivery. He did not create a hard to handle racing machine. I've got several dyno prints to compare the different settings. He got to 277 hp at one stage, but that was peak power, it would only be there for a very short period of time. From there he started to detune the engine to obtain a better torque curve and a more balanced ride. At 272 hp he was almost pleased, but at 270.6 hp he got the perfect torque curve.

Turbolag seems to be a little bit more pronounced than with the small T25. From 1900 rpm power really starts to build up and just before 2800rpm there's the full power that lasts until the redline. The engine is much stronger in the 4500 to 6000 rpm range now.

Power is now just between the 9-3 Troll (260 hp 2.0) and 9-3 Troll R version (280 hp 2.3). The base for the ECU is a Troll ECU. It was modified to match the 900. According to Renato, the Viggen intake setup I'm using now is the most restrictive part. The next thing to do will be freeing the intake. ERP has done the same on his TD04 equipped SQR 900.

I've been thinking about buying the big Hirsch Performance intercooler. On the 900 it would make a 10 to 15 hp difference, but only in situations where the Viggen intercooler gets heatsoaked, like on the repeated dyno runs we did and on sustained high boost, like driving at very high speeds on the Autobahn for a longer period of time. For short bursts of power the Viggen intercooler will do fine. The mesh I'm using in the Viggen bumper to protect the intercooler didn't help performance. It blocks the airflow, so I'll start looking for something that's not as finemeshed.

The noise the car makes on the dyno is deafening. After 3 or so dynoruns, I decided to wait in the showroom upstairs. Although the dynoroom was insolated with sounddeadening material, the roar from the 900 at full power could be heard in the showroom. I'm still not sure wether it was fun or embarrassing

The way back home to the Netherlands was fun, most of it is German Autobahn
. Still can't get that big grin off my face
This Sunday I'll meet up with some fellow Saabscene members at the Nurburgring to do some more testdriving


edit:
Renato, I know you are reading the posts on Saabscene , so thanks again for the great job you did!
 

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Lordy, I'll bet your baby flys.

Note to self, don't go picking on 900's anymore as it might be one of these monsters.
 

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Is that est crank hp or wheel hp?
I don't know how much hp the Viggen turbo is able to put out, but I do know that on my car the turbo starts to cut boost at high rpm. Seems to run out of breath! Could be just the ecu trying to save itself?

Also, a larger intercooler will typically give you more power regardless of heat soak. Reducing the pressure before the intercooler decreases the temp of the gasses going into it because they don't have to be "pushed" as hard to go through. Not sure if it would be 15 hp from just that, but it would make a few ponies. (not to mention looking really cool )
 

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Discussion Starter #7
Originally posted by Adrian W:
[qb]crank hp or wheel hp? [/qb][/b]
It's crank hp. The Hirsch dyno in Switzerland is at much higher altitude than where I live, here in the Netherlands at sealevel. The dyno compensates for that, but I'll do a dynorun at the local speedshop to see if there's a big difference.
Another factor that influences the power is the ambient temperature. After doing so many dynoruns (used up a quarter to a third tank of fuel) in a short time in a small dynoroom it gets hot inside.

[qb]I don't know how much hp the Viggen turbo is able to put out, but I do know that on my car the turbo starts to cut boost at high rpm.  Seems to run out of breath!  Could be just the ecu trying to save itself? [/qb][/b]
Boost taper is often programmed in the ECU. Mine starts at 1.25 bar and tapers off as the rpm's rise.

[qb]Also, a larger intercooler will typically give you more power regardless of heat soak.  Reducing the pressure before the intercooler decreases the temp of the gasses going into it because they don't have to be "pushed" as hard to go through.  Not sure if it would be 15 hp from just that, but it would make a few ponies. (not to mention looking really cool        ) [/qb][/b]
The Viggen intercooler flows very well, that's not the problem, it's the heatsoak that might hamper better performance.
The quoted 10 to 15 hp will only be gained at sustained load. Bolting on a big intercooler will not get you an instant 15 horses. What it can do is compensate for the loss of power that a very hot small intercooler would suffer from, that might give a 10 to 15 hp difference. Most of the times the Viggen intercooler has the time to cool down a bit between consecutive demands for full power.
The temperature of the inletair also influences the intercooler's efficiency. The hotter the inletair, the bigger the drop in temp will be. So on a 270 hp 2.0 a bigger intercooler will make more of a difference than on a LPT.

Since the airco is removed, there's plenty of space to install an even bigger intercooler.
A Mitsu Lancer EVO maybe???????????
 

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You never mentioned the torque. What is it now?

Congratulations, it sounds like you are happy with the results.

We'll see you on Sunday and Mark will need to borrow it to have any hope of keeping up with me on the Ring. The moose smoked the 9k on the autobahn today.
 

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By the way, Mark is currently underneath the 9k with a spanner in a desparate search for more power. He also made an appointment at Ring Racing Sunday morning to see if they can work some magic for him. God knows, he'll need it!
 

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Beauty of a car with a engine like that , i'am very very very jealous .

edit: Renato , please do something to make my Tid going quicker !
 

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What was the wheel hp rating? And for the boost taper in the Viggen, it's possible that it's programmed into the ECU. But it doesn't taper it at any other instances, and it begins to taper suspiciously right after the max power is reached at 5500 rpms.

Hafta find out once these temps cool for a good dyno run. If (for whatever un-explained reason) the car really is putting down 240-250 hp at the wheels, that would certainly explain the turbo running out of breath!
Just hafta wait and see.
 

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Congratulations, Maarten! I would love to have a ride with you on Sunday. I hope I will be able to make it to the Ring, but I don´t think I will. My grandmother celebrates her 91st birthday that day in Stuttgart ... which is about 400 km from the Ring. So even if I can leave at 3 PM, I won´t be able to reach the Ring before 7 PM

Yours,
Philip
 

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Adrian, the boost taper is indeed programmed in the stock ECU. However, with custom programming such as mine or Maarten's, things can be different. Something about removal of top speed limiter as well.
 

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Unfortunately not much use for getting rid of the 155 mph top speed limiter on the Viggen here. Seems a superfluous endeavor considering the fastest you can go here legally is 75, and I'd hafta drive 500 miles out of state just to do that. But that boost taper is a little irritating, next time you talk to the guys at Hirsch ask them if that's programmed specifically into the Ecu of the Viggen. Seems to be less near sea level, and (obviously) more as the altitude goes up. Could still be programmed, just curious about it, as it is at least sliiiightly suspicious. Oh well. Car has lots of
regardless.

Here's an interesting question for you 2.0 turbo Saab owners out there: Why is the compression on the 2.3L motors 9.3:1 and the 2.0L motors 8.8:1 At least on the GM 2.0's. If due to poorer combustion chambers in the 2.0L head perhaps a 2.3L head would be a reasonable upgrade if the opportunity arrived? Or perhaps the shallower combustion chamber of the 2.0 since it has a shorter stroke make it more likely to knock? Should be interesting.
 

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Discussion Starter #15
@Eric: Torque is down 2 Nm compared to the 251hp/258Nm dynorun in Geldrop, about six months ago. However it feels like the car is pulling stronger now
.
Comparing figures from different dyno's isn't very reliable though, they can vary. I'll do a dynorun at Van Kronenburg Motorsport in Geldrop to see what difference the TD04 and Troll ECU really have made. This is what dyno's are meant for, seeing what an upgrade brings you performancewise.

@Philip: I hope you will be able to make it to the Nurburgring.

@Adrian: Removing the speed limiter isn't a very practical feature, you're right about that. My car should be able to reach 260 km/h, but the chassis would not be able to cope with that. I was advised not to try it.

The point about the difference in compression on 2.0 and 2.3 engines is very interesting. Unfortunately I haven't got a clue why the ratios differ.
 

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I think it is just the NG900 that uses 8.8:1 ... but the B234R uses 9.3:1 still ... maybe they just figured the 2.0 would get reasonable gas mileage anyway, and wanted the extra room in case of overboost?
 
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