Increasing turbo boost

ubernub · Post by **ubernub** » Sun Sep 25, 2011 10:56 am

Hello everyone!
I wanted to increase the turbo boost on my L300 2.5TD and found some instructions on how to do it.
I installed a boost gauge, and tested the stock pressure before adjusting. It turned out to be 0.6bar / 8.7psi, which is very low since factory boost is 12psi!
I tried to adjust it up by tighting up the wastegate rod screw, but im not gaining any more boost.
What am i doing wrong?

jessef · Post by **jessef** » Sun Sep 25, 2011 1:55 pm

Factory boost is 8-9 psi.

11-12 psi is the max you want to push it in stock format.

ubernub · Post by **ubernub** » Mon Sep 26, 2011 9:37 am

jfarsang wrote:Factory boost is 8-9 psi.

11-12 psi is the max you want to push it in stock format.

As im reading the manual with specs right now, I can tell you that you're wrong. It says that the wastegate should open at 11,9 PSI on the 4D56T engine.

jessef · Post by **jessef** » Mon Sep 26, 2011 3:10 pm

How many turns are you doing?

tiitus · Post by **tiitus** » Mon Sep 26, 2011 10:50 pm

Boost don't go up if there is no more fuel.

ubernub · Post by **ubernub** » Tue Sep 27, 2011 1:14 pm

tiitus wrote:Boost don't go up if there is no more fuel.

Could you explain how to increase the fuel flow? pics would be nice!

yojimbo · Post by **yojimbo** » Tue Sep 27, 2011 1:27 pm

Most of the time though there is plenty of exhaust gas to keep increasing the boost, thats why you need a wastegate to vent it, you can prove it by pulling the pipe off and seeing how much boost you get.

tiitus · Post by **tiitus** » Tue Sep 27, 2011 10:39 pm

ubernub wrote:
Could you explain how to increase the fuel flow? pics would be nice!

Loose that 13mm nut and turn (in) center bolt, first half round, then thigten
nut and try. If it's ok, you have more boost.

But don't get you boost too high, or you need a new engine.

ubernub · Post by **ubernub** » Thu Sep 29, 2011 6:58 am

tiitus wrote:
ubernub wrote:
Could you explain how to increase the fuel flow? pics would be nice!
Loose that 13mm nut and turn (in) center bolt, first half round, then thigten
nut and try. If it's ok, you have more boost.
But don't get you boost too high, or you need a new engine.

Thanks! there was a little brass cap on the adjustment screw, but it was easy to remove! It smokes a little black when i rev it, and when flooring it on low boost.. Black smoke doesnt harm anything on the engine? is it possible to damage anything if i turn it up to make a smoke machine? hahe!

The turbo boost is up to 0.8BAR / 11,6PSI now, noticeable difference! :)

thedjjack · Post by **thedjjack** » Thu Sep 29, 2011 9:29 am

My experience is black smoke = unburned fuel = HEAT... Watch EGT...

My fiends Cummins on extreme tuning makes lots of black smoke and 975 ft.lbs of torque but you have to watch the EGT as it goes extreme real quick....but fun fun fun...

ubernub · Post by **ubernub** » Thu Sep 29, 2011 1:48 pm

thedjjack wrote:My experience is black smoke = unburned fuel = HEAT... Watch EGT...

My fiends Cummins on extreme tuning makes lots of black smoke and 975 ft.lbs of torque but you have to watch the EGT as it goes extreme real quick....but fun fun fun...

HMm! I dont have any EGT gauge, maybe i should turn the diesel pressure down again? what could happen if the exhaust gas temp gets too high? broken turbo? the engine temp gauge in the car is always on bottom of the "OK running temp line" when its fully heated.

What could happen if i ran too lean? (too little diesel)

ubernub · Post by **ubernub** » Thu Sep 29, 2011 1:48 pm

thedjjack wrote:My experience is black smoke = unburned fuel = HEAT... Watch EGT...

My fiends Cummins on extreme tuning makes lots of black smoke and 975 ft.lbs of torque but you have to watch the EGT as it goes extreme real quick....but fun fun fun...

HMm! I dont have any EGT gauge, maybe i should turn the diesel pressure down again? what could happen if the exhaust gas temp gets too high? broken turbo? the engine temp gauge in the car is always on bottom of the "OK running temp line" when its fully heated.

What could happen if i ran too lean? (too little diesel)

thedjjack · Post by **thedjjack** » Thu Sep 29, 2011 2:37 pm

too much exhaust heat will blow the motor...crack head, melt valves, melt pistons, melt turbo....

Extreme exhaust temperature will not show up in water temperature as the motor will melt prior to water getting too hot.

EGT/Pyro are repetitively cheap..

You can go as lean as you want eventually it will not run....and only get colder and colder (it is opposite world to gasoline engines)...

jwfchase · Post by **jwfchase** » Thu Sep 29, 2011 8:57 pm

I've always wanted to try upping my boost, but not until there's a pyrometer onboard...

Is your exhaust system stock or have you gone to a 2"- 2 1/2"?

ubernub · Post by **ubernub** » Thu Sep 29, 2011 9:58 pm

[quote]
Is your exhaust system stock or have you gone to a 2"- 2 1/2"?[/quote]

Its stock.

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