UrS4 tuning success story

Mihnea Cotet mik at info.fundp.ac.be
Sun Jan 19 21:24:24 EST 2003

Hi all!

I just wanted to vent my happiness for what happened yesterday with a
friend's UrS4.

He had some chips in it with a 3 Bar MAP sensor, but he couldn't get proper
boost from the engine without having and hearing knocking...

So yesterday I went to his place with all my equipment and tested the car,
no fault codes, everything perfect. We then test drove it and got no knock
at boost pressures lower than 1.5 Bar (2.5 absolute). Then we turned the WG
spring down 2 turns, went for a drive and wow! I've gotten to hear knock
for the first time in my life, and hell it doesn't sound good or
reassuring! Then I opened his ECU, pulled the chips, read them and started
working on the maps inside. And there was the surprise! His chips software
was made for an enormous turbocharger, RS2 injectors and a huge intercooler
as well, plus probably some very high octane fuel. 27 degrees advance at
WOT/7000 RPM and a little lower than that at lower RPMs/WOT... Man, who's
the dumba$$ who did those chips??? The timing advance map for "recognized
knocking" was only 3 degrees retarded from the main map, so no wonder we
could hear knock!

So I set off to work and modify his ignition advance map, then added a
little more fuel, and meanwhile he installed a set of 3B injectors,
retaining the stock UrS4 fuel pressure regulator, so he could have a little
more fuel in order to protect his engine and get a few more horses out of
it. Then we burnt the chips, and went for the test drive that was going to
reveal if I knew what I was doing or not (though my friend didn't have a
doubt that I knew it). Well, at 1.6 Bar, the result is blasting! Whereas
before he used to have a nasty "flat spot" between 2 and 3k RPM at WOT and
not get proper boost below 3300 RPM (we measured 0.8 Bar at 3000 during the
first test drive), he now has 1.35 Bar at 2800 RPM and 1.6 at 3100 or
thereabouts. The car now pulls strongly to the redline with no signs of the
ECU backing off the advance at whatever RPM and no more flat spot either.

About 2 hours later when I was almost at home, he called me from Paris
(which is some 400 km away from his place BTW) to thank me again for the
good work and to tell me that his car never pulled so strongly as now!!! I
guess he slightly ignored the speed limits in order to get to Paris in such
a short time but oh well...

Sorry for the long post but I needed to somehow vent my pride! :-)


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