1995 850T Adjusted turbo waste gate and wow!

850TurboTurtle · Post by **850TurboTurtle** » 27 Sep 2015, 19:56

I only gave the wastegate adjustment one full turn and I'm amazed at how much more responsive the car is when accelerating or flooring it to pass. It's like a different car: feels like another 40-50hp. (I can't imagine what two turns would do!)

So my question is, can these old engines handle the extra power, or is it really the same power just appearing earlier in the curve? (Meaning, are the internal stresses on the engine about the same as normal, it just gets to the normal max 'stress' faster?) I love having the extra power there if I need it, though I generally drive pretty laid back. I just don't want to take a year off my car's life.

I know if you go much over two full turns you get too much boost at low RPM and risk rods or other problems, but what about under 2? Should it handle it fine?

Post by **j-dawg** » 27 Sep 2015, 22:54

Grab a Mityvac and find out how many PSI you're opening the wastegate at. It's possible that you've set it correctly, and you're just back up to factory spec, in which case there's nothing to worry about.

Post by **abscate** » 28 Sep 2015, 05:12

There aren't shortcuts adjusting this stuff other than following the factory settings, which require the precision pressure gauge and time. The mantra here is the 2 full turns past stock are ok on a -1998 but much less on 1999+

Post by **mecheng** » 28 Sep 2015, 10:25

Like the others stated, don't go more than two turns in general. And yes you are correct, it shouldn't affect the peak boost, it will just reduce the lag. In my 98 T5, it still has lag, but it is more bearable with 1 turn.

Post by **Clemens** » 29 Sep 2015, 03:13

So, will moving the boost curve to the left (boost kicks in earlier) increase the torque? HP ratings won´t really be effected, at least not peak hp, I believe.
Just curious cuz the AT equipped turbos have reduced torque and hp (at least on the 96 and 97 R) so I wonder if that could cause an increase of torque into an unsafe range (for the AT, not the driver).

Post by **mecheng** » 29 Sep 2015, 09:31

Clemens wrote:So, will moving the boost curve to the left (boost kicks in earlier) increase the torque? HP ratings won´t really be effected, at least not peak hp, I believe.
Just curious cuz the AT equipped turbos have reduced torque and hp (at least on the 96 and 97 R) so I wonder if that could cause an increase of torque into an unsafe range (for the AT, not the driver).

I've read people safely putting 300hp on the stock 4 speed trans without any issues. It is a very well built transmission, fluid change every 50,000km and it should not cause any issues.

Post by **Clemens** » 29 Sep 2015, 14:35

300 hp with an AT? Interesting... I read somewhere that on the 96 and 97 R the hp was reduced to 240 and limited to 300 Nm (Motronic 4.3 as in the T-5R) in the AT models opposed to 250hp and 330 Nm (Motronic 4.4) in the MT models (not available in the US) in order not to exceed the max torque and hp for the Aisin Warner. But maybe the idea was to stretch the max torque band wider by reducing max hp because that is more useful with the 4-speed AT.

Post by **j-dawg** » 29 Sep 2015, 18:37

The issue with boost coming on too soon is detonation, not transmission damage.

Post by **matthew1** » 29 Sep 2015, 20:05

A guy around here has been over 300hp in his '95 or '96 850 R for several years.

Post by **Clemens** » 30 Sep 2015, 01:48

@j-dawg: where´s the detonation coming from?
mixture too lean or not enough timing advance?