wfofromthegetgo

Hi everyone, my first post here so just wanted to introduce myself. I just picked up a 5000 CD Quattro for REALLY cheap. I'd like to put a few little mods on it just for fun. I've done a search and everyone seems to put a stiffer wastegate spring and chip first. I used to have an 87 Supra Turbo and just using a bleeder valve to control boost was pretty sufficient as far as power went. Can I do this to the Audi or will the ECu not supply enough fuel? I guess my question is, is it even worth putting a manula boost controller on without someway of increasing fuel?

Thanks!

MarkPan

but the ECU cuts the fuel (via fuelpump relay) if the boost goes over 1.6bar ( 0,6bar absolute.. like uh 8.x PSI ?)

so you need to either chip the ECU, or R-mod it. Timing etc goes off a bit with an R-mod though, because you're making the ECU think there is boost than there actually is.

best to get a chip! :-)

Adam Mowafy

Do the R mod (resistor mod). its fairly easy if you're handy with a soldering iron. All this does is fool the ecu into thinking it is seeing less boost. overboost is counter-acted by shutting off the fuel pump. The whiplash factor.

Open the ecu up and look for pins 1 and 10 on the pressure transducer. there is is plenty of pin to solder to as they are very long.

solder in a resistor or a potentiometer between 1 and 10. I cant recall which size resistor to use? it really depends how much you want to fool the ecu. I wouldnt run more than 16lbs of boost without doing anything for fuel.


Get a ball valve type MBC from ebay, they are dirt cheap and work very well. just make sure when usng ball valve type that you put it inline on the lower wastegate hose and leave the top open to atmoshpere.

heres a link to a cheap and effective MBC:<ul><li><a href="http://cgi.ebay.com/ebaymotors/Manual-Turbo-boost-controller-MBC-0-30-PSI-pt-cruiser_W0QQcmdZViewItemQQcategoryZ33742QQitemZ803 5217223QQrdZ1">http://cgi.ebay.com/ebaymotors/Manual-Turbo-boost-controller-MBC-0-30-PSI-pt-cruiser_W0QQcm

boxerfan

I installed a pressure regulator after trying an el cheapo needle valve. The needle valve worked but wasn't very good. A working WGFV is the best option, but the MBC (manual boost controller) isn't bad.

The code in the stock ECU has the fuel cut at 1.60 bar, the common chip code floating around has the fuel cut raised to 1.95 bar. You can thus increase your boost by just less than 0.2 bar before hitting the abrupt fuel cut level.

The R-mod, while cheap and effective does fool the ECU and throw off the timing somewhat. Consider that the original ECU design can handle levels to 1.6 bar where it shuts down the fuel pump. The QLCC code adjusts the fuel cut level, boost map and WGFV control to allow the ECU to control the WGFV and apply more pressure to the WG holding it closed and allowing boost to build higher.

I run a chipped and r-modded ECU with a stiffer spring... but I did also take care of the fuel issues that start to appear at 1.8-1.9 bar.

HTH...

wfofromthegetgo

ok, great, thanks guys. well, I got it back to my place today and was looking around under the hood. Is the wastegate the black thing just on top of the intake manifold that has a rubber diaphragm on top of it? If it is, then mine looks like its missing a bolt that goes into it. Does this mean the wastegate is always shut?

icon73

wastegate is behind the intake manifold attached to the downpipe of the exhaust.

wfofromthegetgo

ha ha! of course it is! i don't know why I would think it was a wastegate considering it isn't connected to the turbo or exhaust in any way! anyone have a used crusie control valve they want to sell?