Hi,

was adjusting wastegate rod but forgot where i started, so i bought a boost gauge and now i have set boost pressure to 1.3bar. 

Been searching for boost pressure value but only i find is "1.3 bar is not too much"

Anyone know what the correct boost pressure peak is?

Turbo is Garrett 750453-1

Thanks.

The 109 uses a VNT turbo.  That rod controls the VNT vanes, not a wastegate.  Be very careful adjusting it.

I'm pretty sure I've seen more than 1.7 bar (25psi) on these under heavy load uphill but it's been a while since I owned one.

Hi , thanks for rapid response.

I had to watch and learn about vnt right away.

Sounds like im on the safe side with 1.3bar , perhaps i will give the rod 1/2 turn to get to about 1.4bar .

Thanks

Adding VGTDC variable geometry value

At idle ~800rpm my VGTDC value is ~67%.

Would be great if someone could check and share what value you have?

Perhaps thats a better way to go than Boost pressure value ?

4 hours ago, fofo said:

Adding VGTDC variable geometry value

At idle ~800rpm my VGTDC value is ~67%.

Would be great if someone could check and share what value you have?

Perhaps thats a better way to go than Boost pressure value ?

I don't have the same car as you now so I can't help you with the VGTDC value, but what is probably more relevant is that the maximum Boost measured at the MAP, which includes Atmospheric Pressure, should be a little over 2.4 Bar and certainly no more than 2.5 Bar.

This might be slightly less than the Boost Pressure measured at the Turbo pre Intercooler and the Throttle Valve is never completely closed as well so that might reduce it as well.

This Pressure will only be achieved when the car is driven hard and only momentarily.

The Map Pressure at Idle should around 1 Bar, be the same as Atmospheric.

What I would also say is that if the expected Boost Pressures were a long way out then I would expect a Fault Code for under or over boost.

19 hours ago, Tizer said:

I don't have the same car as you now so I can't help you with the VGTDC value, but what is probably more relevant is that the maximum Boost measured at the MAP, which includes Atmospheric Pressure, should be a little over 2.4 Bar and certainly no more than 2.5 Bar.

This might be slightly less than the Boost Pressure measured at the Turbo pre Intercooler and the Throttle Valve is never completely closed as well so that might reduce it as well.

This Pressure will only be achieved when the car is driven hard and only momentarily.

The Map Pressure at Idle should around 1 Bar, be the same as Atmospheric.

What I would also say is that if the expected Boost Pressures were a long way out then I would expect a Fault Code for under or over boost.

Hi and thanks very much for your respons, and very good info.i have been working so late respons

I checked the MAP and it was 2.34 bar at peak.

I  shortened the VNT  rod 1/2 turn and ended up at 2.32 bar peak.

So i assume longer rod more boost pressure, is that correct?

If i have low boost will it respond better from idle and up?

I´m sure its basic questions but i am confused.

4 hours ago, fofo said:

Hi and thanks very much for your respons, and very good info.i have been working so late respons

I checked the MAP and it was 2.34 bar at peak.

I  shortened the VNT  rod 1/2 turn and ended up at 2.32 bar peak.

So i assume longer rod more boost pressure, is that correct?

If i have low boost will it respond better from idle and up?

I´m sure its basic questions but i am confused.

I'm not certain what way the rod should be turned to increase boost, if you turn it the other way and check the maximum boost you should be able to work things out. It will only achieve maximum boost under extreme load though.

I don't think that having a higher or lower boost than what was designed for will make the car drive better at lower revs. The PCM will control not only the Boost but also the Fuel Pressure, amount of Fuel Injected, the Timing of the Fuel etc as well as the Boost Pressure, so changing one of those things will most likely just confuse everything.

If you want the car to develop more speed or low down power then there must be lots of tuning companies that can Remap it to your requirements.

Thank you, i´ll adjust the rod and find out.

 

Hi, an update for those coming after me, shortening the VNT rod increases the boost.

I ended up at 1.4bar at boost gauge and 243kpa at the MAP and i am satisfied with that.

 

5 minutes ago, fofo said:

Hi, an update for those coming after me, shortening the VNT rod increases the boost.

I ended up at 1.4bar at boost gauge and 243kpa at the MAP and i am satisfied with that.

 

That looks to be perfect and if the car drives ok then it would be a good idea leave it as it is.

Hi , an update for those intrested.

Car felt harder to get running on clutch release with MAP 240kpa imagination or not but so it felt. Hotter turbo also i believe

So i turned vnt rod 2 full turns(longer rod) and ended up at MAP 220kpa. Now it feels better and i¨m keep this setting(for now....)

PS, rod can be turned without removing hat c-clip(lost mine) holding rod to turbo, just release 2 nuts holding the vacuum thing and then you can turn the hole rod and vacuum, only full turns is possible, not halt turns.