BV43 turbo upgrade

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desertstorm
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Joined: Thu Apr 19, 2007 9:11 pm
Passat model: B5.5 130 TDI AWX
Location: Cannock

BV43 turbo upgrade

Post by desertstorm » Wed May 18, 2011 10:19 pm

Decided to upgrade the turbo on my 130bhp AWX Passat to make the most of the phase 1 Custom code remap. After seeing posts from Chris (Adams24) on here and searching the net discovered that the KKK BV43 turbo fitted to certain Audi A4 170TDI models was a plug and play option. I believe these were cars made from around early 2005 to the end of 2007 This appears to have been remapped sucessfully to around 210BHP on several engines which is about the limit of existing injectors on my engine so it looks like a good match.
You need to be looking for a 03G145702H, 03G145702HV or 03G145702HX. Part number 5303 988 0109 or 5303 970 0109 from a BRD or BVA engine type.
Removal of the turbo is fairly straightforward if a little fiddly when it comes to trying to undo some of the nuts and bolts securing the lower oil pipe and the turbo to manifold securing nuts. A good 12mm offset ring spanner is needed and some ball ended allen keys.
Here are some pictures of the old turbo and new one.

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There really isn't anything between them physically . The BV43 has an actuator position sensor but that doesn't need to be used at all, the vacuum actuator is very similar to the Garret except because it's plastic it needs a larger diameter vacuum pipe which is a small difference.
Had to modify the turbo a little bit with an angle grinder because I couldn't get one of the nut refitted on the turbo to manifold studs. The ring spanner I was using wouldn't go over the nut because there wasn't enough clearance between the nut and the turbo.

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The BV43 also has a fitting for an EGT sensor this is a 1/4 NPT threaded hole.. I bought my turbo off E-bay from a scrap yard but it never came with the EGT sensor.

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I bought a new genuine EGT sensor off E-bay for £15 and intended just to use this to measure EGT temps to make sure car wasn't running too hot.The Audi sensors are not thermocouples as you may expect. They are 200 ohm Platinum resistance sensors.This isn't something you can connect to a normal EGT meter as they use thermocouples. But you can use a normal multimeter and just measure the resistance.
The table on page 7 of this document allows you to convert ohms to degrees C.

http://www.heraeus-sensor-technology.co ... chuere.pdf

I have seen mine upto around 840 degrees C max when accelerating through the gears.After reading round on the net it appears that 900 degrees is about the highest you want on an intermittent basis.

I have adjusted slightly the stop and stroke of the rod on the actuator to improve the driveability of the car.I would recommend altering the actuator bracket where it mounts on the turbo.

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You can see the actuator has a slot for the one bolt fitting. The other bolt is at the back of the turbo and if you want to alter the stop or stroke of the actuator you really need to undo both bolts that secure it so you can adjust it. The problem is the bolt closest to the manifold is very fiddly to undo and because it is in a hole and not slotted you have to take it all the way out.I slotted the hole so you only need to loosen the bolt at the back.
The vanes work a little differently to the Garret in that they almost close off the flow of exhaust gas when the actuator hits the stop so very small adjustments only here.The ends of the vanes line up to form a circle with very small gaps end to end.
Logging block 11 on VAG-COM gives you RPM, Specified boost, Actual boost and the duty cycle for the N75 valve.
I drove around and logged this then converted it to a chart on Excel which makes it a lot easier to see.

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The actual is not keeping up with the specified very well. The way the actuator works on the Audi will be slightly different because the ECU actually knows the position of the vanes so is probably more accurate in controlling the boost.I shortened the boost actuator adjustment by 3 or 4 mm and tried again.

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This time there is a better track between specified and actual and car felt better to drive as well, Not as flat at lower RPM. You can't shorten the rod too much as otherwise the turbo will spike and overboost and there will be more back pressure because the vanes are not fully open, this will increase EGT's at high RPM. You are looking for the duty cycle to be around 75% at 4000 RPM this means the ECU has some room left to control the boost by opening the vanes more.The way it is at the moment that is the case.On flat out acceleration the turbo produces 1.7 bar boost around 2400 RPM this tails off to about 1.45 bar at 4000 rpm and it's still keeping up at 1.3 bar at 4800 RPM. This is with a custom code phase 1 map which is for a standard turbo. To get the most out of this it needs another remap to use the boost available. Will hopefully get it on the rolling road soon and see what it's doing :D .
Gone but will never be forgotten
207Bhp 347Lb/ft 14.9 seconds 93mph
The build topic viewtopic.php?f=5&t=56110

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The new 382bhp Audi viewtopic.php?f=5&t=70765

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