Tune for 3 bar map sensor

Depending on which ecu, tolerance for aggressive control is generally 130-200 kPa depending on which gain component. Some have it as 300 kPa. So in a manner of speaking, any value within .2 or .3 bar is "kind of" considered "good enough" by the ECU. IOW corrections are less aggressive in this area, close to the setpoint. Outside that tolerance band, the gain corrections are considerably more aggressive.

that is why you do not want to run specified boost too close to the limit of the measuring range of the map sensor. If you do, the ECU won't correct for overboost spikes aggessively enough. (and EVERY properly adjusted turbo will spike a little on transients, at times, by design. If it does not, the response is overdamped or "too slow" which may look ok on a low-resolution vcds log but it drives like crap) That's why I INSIST on a 3bar with any upgrade turbo. Unless they don't mind stock turbo performance.

can you add a 3 map sensor and have malone tuning set it for a 3 map or do you need some modifications also? only mods i have is 520's and no cat.

VW_TDi_ said:

can you add a 3 map sensor and have malone tuning set it for a 3 map or do you need some modifications also? only mods i have is 520's and no cat.

Click to expand...

Yes you can add a 3bar map sensor, and have it tuned for. HOWEVER, your 3 bar map sensor would be a waste of money until you upgrade turbo. Then when you upgrade turbo, you'd have to do another software flash to it, or else the upgraded turbo will be performing like a stock one, more or less.

So then you'd spend twice the money on software.

Now if you learn/have the capability of tuning yourself, it wouldn't be too much of an issue.

If you're hitting 90+% I feel the actuator setting is the problem.
I've never seen the n75's fail and cause too much boost...
I have taken quite a few apart and tested them.
Usually they leak vacuum due to dirt and not being able to seal well closed. The vacuum ends up leaking , and you have lagginess and a low vac reading on the feed line (which goes away when you remove and plug the n75 vac feed)
Or, the dirt that builds up makes it harder for the VAC source to go to the turbo actuator (reducing vanes).

With age, the actuator internal return spring gets weaker and makes it harder for it to work against the exhaust flow against the vanes (to open up). 90%+ just explains that here...
Test it out, look for 20-22 in Hg setting where it hits the stop.


KERMA, exactly. If you are running anywhere near to the limit of the 2.5 bar map sensor- which is 1.5x 14.7=22 psi approx, you really should go to the 3 bar map, to give some leeway. On a vnt15 at typical 18-19 psi max, it works well.. but not the vnt17 or higher. Sure you can use a boost valve to control spikes, but that's a bad solution that adds lag.
Why?
You can set it to crack at 22 psi for example. Max vacuum is pretty much -14.7 psi gauge.
So, let's say you are at 15 psi, and the ecu tells the n75 xx% which gives max vanes at around -10 psi (or higher) to spool up quick.
The boost valve will be opening up and limiting what the ecu asked for. 15 - (-10)= 25 psi.
In reality, the n75 would be giving 3 psi less vacuum to the actuator, adding to lag.
The closer you get to the set point, the less vac can be given.
That being said, a boost valve can be set as a LAST RESORT control.
In my case, 24 psi or so VNT17, I set it to crack at 32 psi. So if something does happen, the most it will let the turbo hit is 32 psi, by then I can tell by the gauges, the turbo/n75/ecu/map sensor has a problem.

Well, setting my SVBL at 2300mbar has kept me completely limp free for about 1 week now, with lots of repetitive testing of the same scenarios. I put that second N75 map back to stock for now.

Thank you Kerma and robnitro for the clarifications above.



Now onto how to gain some mpg's back due to using the power more often... (BTW, my Jetta is now much faster than a Chevy Sonic Turbo now. Yay. Had one try to shut me out on a lane merge after a light)

Gotta love the flat HP of the TDI, I'm pushing about 180 hp from 2700-5500, that sonic may have more hp than you but in a smaller range, and if they aren't in the right rpm range, a flatter Hp engine will have more real power.

A good case:
A friend had an evo 8 with 380 hp/ 420 ft lbs. 380 hp from 4000-7200.
At the drag races with sti's/evos he beat many 400-420 hp cars... they were making their 400 or so hp between 6200-7200, but before 6500, it was dropped lower- probably less than his 380 flat hp. So like calculus tells us about integrals: the area under the curve between the limits of rpm you are in gear is the real hp that gets used... if you have a peaky engine, the average is much less than your peak
Also turbo lag on the 400+ evos/sti but on a drag strip turbo lag is less of an issue than normal driving or road racing.

i bet you cant see above 2600mbar in vcds....

chances are the diag limits will need changing

makesure to check the voltage and scale

for example on my 4 bar sensor its 250mv to 4.48v 289mbar to 4bar

I bet this thread is almost 6 years old too.

oldie but goodie