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Discussion Starter #1
I've located a turbo from a 94 9000 Aero.
Does anyone know if this will work with a NG900?

I'm told it has an oval exhaust port. But I as I have the 3 inch downpipe that fits the t25 housing, need to know if this will work..., and what are the disadvantages considering I have a stage 3 ECU setup now?

thanks

DC
 

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I assume you mean a TD04 turbo ?

TD04's can be made to fit.. but it's new coolant lines, oil feed lines and air intake feed too..

Plus.. you'll get a bit more from it on a custom mapping rather than on a stock mapping.

It's a bit more efficient (and reliable) at higher boosts, therefore runs a bit cooler which is a good thing...
 

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Discussion Starter #3
Your right....it's a TD04. Going for $350, and looks like its in pretty good shape. Been considering the stage 4 for my Maptune now.

What about the wastegate? Any idea on the
adjustment it will need?

DC
 

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It's possible to fit a TD04 to a B204L engine. As Mark already said, new coolant lines and oil feed lines are needed. The new air intakepipe is only necessary when a Mitsubishi TD04HL-15T-5 is used. This is the turbo as used on the Viggen and T7 Aero models.

There's also a TD04HL-15T-6 which was used on the 9000 Aero. The 6 version is capable of more hp at the expense of spoolup time. The area where the exhaust gasses leave the manifold and enter the turbo is slightly larger and has a different shape. Because of the smaller turbine inletport of the Viggen spec TD04, gasses will enter the turbo at a higher speed and make the turbo spool up faster. At very high revs it's a bit more restrictive compared to the 9000 Aero spec TD04.

So it's not the downpipe that needs to be adjusted, it's the exhaust manifold. It can be ported to make the transition from the exhaust manifold to turbine inlet very smooth. The turbogasket is oval and can be helpfull when marking the shape on the manifold.

Compared to the stock T25, the TD04HL-15T-5 has a little more lag. With the TD04HL-15T-6 it will be a bit more noticable.

Past 4500 rpm a T25 starts running out of breath, but the TD04 keeps pulling right up to the redline.

Wastegate adjustment depends on the software supplier's advice. I've been told by the Brittish Maptun sales agent that Maptun has developed a Trionic programme for the B204L TD04 combo.
 

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Originally posted by MarkA:
[qb]Perhaps.. it's cos he's done it on HIS GM900 huh ?    :thumbsup:        [/qb][/b]
If I had to do it all over again, I would have opted for rebuilding my T25 and adding a T28 compressor wheel. No hassle with lines or intakes.

I went the TD04 route because the turbo is said to be a bit more sturdy than the T25. The results of the TD04 project are great, but I never expected so many additional costs.
 

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Discussion Starter #9
Based on your last Maarten, Would you say a hybrid type is a better solution..?

Using the spoolup speed of the t25, and the power of a t28.

Frank
 

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Originally posted by Maarten (900 Hirsch):
[qb]Compared to the stock T25, the TD04HL-15T-5 has a little more lag. With the TD04HL-15T-6 it will be a bit more noticable.
[/qb][/b]
The TD04HL-15T-5 on my GM900 actually spools up slightly faster than the T25. However I have ported the turbo intake and have 3" intake pipes. I am using Mobil 1 15w-50.

Originally posted by Maarten (900 Hirsch):
[qb]Past 4500 rpm a T25 starts running out of breath, but the TD04 keeps pulling right up to the redline.
[/qb][/b]
I have found that my TD04 begins tapering off at 5200 rpm. At 6000 rpm it is down to 16 psi and at 7000 rpm it is down to 13 psi.

Originally posted by Maarten (900 Hirsch):
[qb]Wastegate adjustment depends on the software supplier's advice. I've been told by the Brittish Maptun sales agent that Maptun has developed a Trionic programme for the B204L TD04 combo. [/qb][/b]
This is not difficult. During the SOC this summer SQR made a custom ECU for my GM900. All that was needed was the base boost at every 1000 rpm. It then took Frank Stromqvist about 5 minutes to make a custom program for me, with an extra 10 hp and 800 rpm.

Eric
 

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Only 5 minutes to write a custom programme?
Did he bring a base programme for a TD04 2.0 engine?

It took Hirsch 30 minutes to adapt the Troll programme for the TD04 so it delivered maximum hp. A lot more time was used to finetune the torquecurve, doing numerous dynoruns.

Apart from the ported turbo intake and 3" intake pipes the differences are probably down to the way Trionic was reprogrammed. Mine also tapers slightly at high revs, but it's nothing compared to the T25.

It's a shame we can't testdrive our cars back to back. It would be interesting to know what impact the small differences in tuning have in real life.
 

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Discussion Starter #13
Thanks everyone..., I guess my quest continues then. Havent' purchased the turbo yet..., rebuilding the turbo I have is probably left best with a turbo expert...but at $750.00 hmmmm, even the dealer might be less.

I decided not to purchase the td04...6cm2, due to it being off of a junkyard special 94 9000...

Found a rebuilt viggen td04...5cm2 for $550.00
Ebay had a garrett t25/t28 for $200...with a square exhaust port...appears to fit the japaneze type autos... wonder if it will fit a SAAB.


DC
 

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Actually Maarten, it took more like two minutes for Frank to write the new software. He did it on his laptop in his hotel room. I watched him do it but could not read or understand the program. There were a bunch of vertical lines that he kept highlighting and dragging. All I can say is Frank knows his stuff. My torque curve consists of 3 straight lines. He also gave me the extra hp on less boost. I was using a MBC to hit 25 psi, but Frank brought it down to 21 psi. I’m sure you’ve seen it but here is the link: http://www.lehigh.edu/~erp4/Dyno2.html
One of Frank’s tuning traits is to create only moderate torque in the midrange, but more hp at the high end. If you look at the numbers for Frank’s ECU and compare it to other tuners you will notice his have about 10 ft-lbs less max torque but 10 more hp. I asked him about this and he told me he does that to preserve the transmission.

Have you dynod your Saab Maarten? I would like to see what it looks like.
 

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ERP it's interesting how Frank was able to get more hp with less boost. Cyllinder head, piston, and spark plug surface temperatures all increase the sensitivity to knock and it's possible that by reducing the boost down low the temps are cooler up in the high end. A couple of SCCA racers I know use ceramic coatings to get around that because they keep heat from building up on the surfaces. Neat stuff ...

As for the TD04 on the NG900 ... sounds like a good idea. And if you ever want more power it has many larger trims to upgrade to such as 18 and 19T.


Cheers,
Dubbya
 

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Hirsch also uses less low end boost to help out the top end hp numbers. I run 1.15 bar or 17 psi peak and a programmed 0.9 bar after about 5200 rpm. My car dynoed at 260 hp at the flywheel. The difference between mine and ERP's is that I still have a stock T25 turbo. So the TD04s better flow and efficiency higher up are the reasons his gets more power than mine. Also, Maarten's car probably runs similar boost to mine since he also has a custom programmed Hirsch ECU. He also has a TD04 and on the same dyno as mine, got about 10 more hp.

The reason the lower boost works is the fact of more heat being generated by sending a turbo out of it's efficiency range. They also explained to me that is somewhat also has to do with the small turbines sending too much backpressure into the cylinders a bit at higher boost pressures.
 

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The reason the lower boost works is the fact of more heat being generated by sending a turbo out of it's efficiency range. -- Eric

Actually that depends on the turbo. If we look at the compressor map for a TD04 turbo we'll actually see that it's peak flow and peak efficiency are both at about 22 psi of boost.

TD04H-15G ... this is similar to the 15T.

Intercooler restriction and intake restrictions all play a role in that. Notice it says pressure ratio and not manifold pressure. A restrictive intake and intercooler will force the turbocharger to feel as though it's creating more boost. This may be the strategy behind the restrictive intake on the Viggen. Because it only runs 15 psi stock putting a restrictive intake and intercooler would make the low pressure side lower, and the high pressure side higher, resulting in a higher pressure ratio and more efficiency at high rpm.

Anyway ... They also explained to me that is somewhat also has to do with the small turbines sending too much backpressure into the cylinders a bit at higher boost pressures. This would cause excessive EGTs. It's probably the primary reason they run lower boost. Keeps the EGT down as long as possible.

Cheers,
Dubbya
 

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Yep... Frank of Sweedspeed says he keeps 900 deg C as a maximum for EGT on road cars, and 950 for racing. This pretty much determines how high the boost can be turned up...
 

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Those numbers sound similar to what I remember Hirsch telling me. I think he said he tunes to about 920 C or so for the road cars. He did mention that 950 C is closer to best performance but 920 C gives that cusion you'd want in the road car for better longevity as well.
 
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