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Discussion Starter · #1 ·
I have just bought a 1998 9-3 diesel. For the first time in a long while, I went for a drive just for fun
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The cost of petrol and poor mpg in my previous 900, sort of kept non essential drives to a minimum!
So, what can I do to increase performance a little This is the first diesel ive owned and dont know much about them (yet, any recommended reading?).
Can I fit a bov? (turbo seems to stall a bit on gear change)
Can I fit mbc?
Ive already taken the air intake that snakes up the wing out. Is a panel (JR) filter or cone filter best option?

Kev
 

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Can I fit a bov? (turbo seems to stall a bit on gear change)

No. Diesels do not have a throttle plate like a gasoline engine. No air is dumped between shifts. Diesels control power by boost pressure and more so on fuel. When you shift the ECU cuts the fuel to drop the RPM instead of closing the throttle like it would on a gasoline engine.

The reason the turbo slows between shifts is that when the fuel is cut there is less heat/pressure to drive it.

The nice thing about diesels, aside from economy, is that when tuned properly they can run nearly limitless boost pressure. Some tractor pulling diesels run 250 psi of manifold pressure through a 3 or 4 stage turbocharger setup. A single stage turbo can usually produce between 30-40 psi of boost.

Dubbya~
 

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IIRC the 900 uses a VNT turbo, which doesn't have a wastegate, and this may also preclude/eliminate the use of a BOV.
 

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Diesel engine changed on 2001 model year TiDs.

Previous units have 115 HP, post 2001 engines have 125HP. There are fairly large differences betweent he two engines with the older one being easier to tune.

Many diesel upgrade companies stock upgrades for the 115hp unit. I'd recommend the Hirsch or 'tuningbox' upgrades for a pre 2001 model TiD.

9-3 TiDs on or after the 2001 model year use a VNT turbo (thus they have no wastegate either) pre 2001 models did not.

TiDs don't use by-pass-valves or dumpvalves because they don't have throttles. Engine RPM is controlled by the super expensive, electronic control, very high pressure fuel pump (costs Euro 2500 from the dealer if it fails).

TiD upgrades interface with the diesel fuel pump to trick it into injecting more fuel than the ECU calls for.

If this isn't done correctly it can result in an overly rich mixture (i.e. not enough air in the mixture) and create lots of diesel smoke under acceleration.

Some companies combine these TiD upgrades with good breathing modifications to ensure that enough air is injested too.

My advice is not to tune a post 2001 model year TiD. The fuel pump is fragile, the fuel pump ECU doesn't allow mapping modifications and generally the air mods necessary to stop it smoking make the car very noisy.
 

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Discussion Starter · #7 ·
Thanks all. Some good info.
Ill start with chassis i think. Ive got some parts off of my 900 i will fit on the 93, then a panel air filter, then maybe the plug in upgrade, funds permiting.
I also have the rear box off a viggen, may put that on too.
 
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