Boost of 1 bar

[prj]

in my map Dmitri, in the motronic i could boost to 1.9-2bar and the rs2 has a 300kpa controller. With the OEM wastegate spring when the car was mapped it could never hit the boost limiter, and the boost limiter was operational, something i checked when i modified the spring screw on the wastegate and i was hitting the boost limiter quite easily.

so maybe to map only up to 280kpa on a 300kpa limiter, maybe its a bit conservative, unless there is another way to set the boost limiter higher somehow, although i doubt it, since the motronic wont know what boost is there when it is above 300kpa.

You might have been hitting load limiter, not boost limiter.
In your software N75 duty is mapped wrong and boost cut is turned off. Load limiter is still in tact though.

[newsh]

Excellent, thanks.

So how much would boost be reduced by? Would you revert to spring pressure or would you get a part reduction, say to 1 Bar or 0.7 Bar?

Well, you can. You can actually boost as much as you want with a 2.5 bar sensor.
This comes at a price though, you have to completely disable the boost limiter, which for very obvious reasons is a pretty bad idea. You also lose feedback control on your boost.

So, if you want to keep it intact, you have to leave some leeway, so you do not trigger it in normal driving.
For example - if you drive up a steep incline in a lower gear, you can have slightly more boost than specified at a moment, and you can trigger the boost cut.

With a 2.5 bar map sensor, the most boost I'd program is 1.35-1.4 bar. With a 3 bar map sensor, I do not go over 1.8 when mapping.
You can always fit a 4 bar map sensor to the ECU if you want more boost - it is not more expensive than a 3 bar sensor and the accuracy is good enough.

[newsh]

BTW, just looked up the Homefry spec. Its max overboost of 1.4 Bar.

[QUOTE .. S2_Central]

snip... the spec is roughly as follows

430Nm circa 3000rpm
280bhp circa 6000rpm
Max overboost is ~1.4bar

Returns ~1-2 MPG better than standard on Optimax

All Motronic safety routines are in tact

All diagnostic routines also in tact - won't appear as chipped when plugged into dealership diagnostic equipment

Absolutely doesn't require any mechanical wastegate adjustment.


[/QUOTE]

[A80Avant]

what is the load limiter?

[prj]

what is the load limiter?

Based on MAF and TPS, not on MAP.

Boost cut = spring boost. But fuel cut will act the same, except it'll be a bit more violent.

[newsh]

So if you had a reduction in boost to say 0.7 Bar and no boost leak what could that be? On the same car WGFV unplugged gave 0.4 Bar.

[prj]

On what software is that?

I'd say heavy knock.

[sjw185]

1bar of boost

Ive been boost leak testing tonight as ive still got one bar of boost!?

Disconnected vac line to rear diff controller and plugged pipe at the rear of the manifold to eliminate that section from the test.

Tested to 1bar from the maf hose with breather still connected, loosing a bit out the dip stick but nothing else showing bubbles with a soapy spray?

Plugged the breather connection on the maf hose and cranked up to 1.4bar test pressure and found bubbles coming out the back of the ISV where the metal crimps round the electrical connection?
dont think this is the cause as it still takes time to return to normal after ive shut the air off??

Will change ISV tomorrow and see what happens?

[newsh]

On what software is that?

I'd say heavy knock.

Just seen this reply.

I think it probably was heavy knock. The engine was burning a lot of oil.

[Christophski]

Hey guys a few friends of mine with a workshop ran the test for boost leak with the kit I got from Andy. We could hear a hiss and made sure all jubilees were as tight as could be but could still hear a hiss. Sprayed with soapy water and couldnt see bubbles. Would the test kit test a leak from the DV or the flying saucer thing? (Dont know its name) Also I guess it could be the intercooler connection but couldnt see it.

Thanks

[newsh]

The test will check the DV for leaks to the outside world but not the diaphragm as both sides of the diaphragm are pressurised.

How much pressure would it hold? You will get a little air escaping from the lower WG chamber into the exhaust. sometimes the WGFV wil leak a little at the solenoid.

[Christophski]

Well I was putting in to 1 bar and then most of it was gone in not to long a time. Maybe 30 seconds. So it could be the dv leaking?

[Jamo]

Have you got a forge dump valve?

[Christophski]

A normal s3 one apparantly but do have a forge one to fit. Do you think this would help cure it?

[Jamo]

The reverse, the forge dv tend to leak and you have to use PTFE tape on them.