Thread: Boost control/max???

Ross.
21psi is the ECU fuel cut out,there is a further "limp home cutout" but I cant recall the boost value.To get more boost you need to adjust the wastegate,if its factory set there will be room for improvement even without the ECU being upgraded.To get the best out of the TD5 you need it to be creating around 20 PSI,ie just on the limiter.
Search "wastegate adjustment" for more info.
ENJOY
Andrew

Originally Posted by LandyAndy

Ross.
21psi is the ECU fuel cut out,there is a further "limp home cutout" but I cant recall the boost value.To get more boost you need to adjust the wastegate,if its factory set there will be room for improvement even without the ECU being upgraded.To get the best out of the TD5 you need it to be creating around 20 PSI,ie just on the limiter.
Search "wastegate adjustment" for more info.
ENJOY
Andrew

I was under the impression that 15psi was max boost on the TD5 Disco and over boost detection by the ECU was 18psi.

But going on the Nanocom, mine was overboosting when it went over 237(there reading) now what is this reading KPa/bar/Atm, BECAUSE if it were KPa then mine was overboosting at 35psi

Baz.

Originally Posted by Redback

I was under the impression that 15psi was max boost on the TD5 Disco and over boost detection by the ECU was 18psi.

But going on the Nanocom, mine was overboosting when it went over 237(there reading) now what is this reading KPa/bar/Atm, BECAUSE if it were KPa then mine was overboosting at 35psi

Baz.

Baz
It's in kpa but you need to subtract 100kpa as it registering absolute pressure, not charge pressure.
Static pressure at sea level is 14.7psi or 100kpa.
Your charge pressure is therefore 137kpa.
The ECU sees the intake pressure sensor signal which indicates 100 kpa as its measuring true pressure. It uses this reading to account for elevation changes and couples it into the fuelling algorithm. Its only used for this purpose. At different elevations you would get readings accordingly.
If you were sat at the beach with it and it read 0, you would stand more chance of suffocating than drowning as technically you have no air!

Cheers


Andrew

Originally Posted by mydot378

Put a boost gauge in last week,working ok till Sat when just stopped reading psi, so what i have found is the elec boost valve r/s,i had the T piece for gauge between the valve and the w/gate,hence the zero psi on gauge.I moved T to other side of valve (boost supply to valve) and yep gauge certianly works fine,over 20psi ,and yes boost cut comes in!! What I want to know is,has anyone removed the elec valve and replaced it with a simple manual bleed valve,eg Turbosmart? Obviously these control boost easily but having the elec unit removed/unplugged would this cause a fault to be registered with the ecu? Standard boost seemed to be around 14-15 psi, what boost can the standard ecu take before the cut comes in?(if the manual bleed valve was fitted) any input appreciated Happy days Ross

Mate, your better off putting your gauge fitting post intercooler. If you do this, damage to intercooler/hoses can be detected as a loss of the "normal running range" on the gauge. I have mine on the piece of pipe where the EGR valve used to be. Get up to 17psi full throttle.
Regards
Robbo

Originally Posted by LOVEMYRANGIE

Baz
It's in kpa but you need to subtract 100kpa as it registering absolute pressure, not charge pressure.
Static pressure at sea level is 14.7psi or 100kpa.
Your charge pressure is therefore 137kpa.
The ECU sees the intake pressure sensor signal which indicates 100 kpa as its measuring true pressure. It uses this reading to account for elevation changes and couples it into the fuelling algorithm. Its only used for this purpose. At different elevations you would get readings accordingly.
If you were sat at the beach with it and it read 0, you would stand more chance of suffocating than drowning as technically you have no air!

Cheers


Andrew

Thanks for that, so in my case 20psi was over boost or 137.9

All clear now

Sorry If I mislead Baz.
Im pretty sure 21PSI is the magic figure.
1.379 on Nanocom is Bar isnt it??? So your 20PSI is about right.
When I tune a TD5 via the wastegate I aim for 1.35 to 1.40 on the Nannocom then fine tune.An auto respods a lot differently than the manual.
The boost box allows 21psi without the fuel cutout.
Andrew

Originally Posted by robbotd5

Mate, your better off putting your gauge fitting post intercooler. If you do this, damage to intercooler/hoses can be detected as a loss of the "normal running range" on the gauge. I have mine on the piece of pipe where the EGR valve used to be. Get up to 17psi full throttle.
Regards
Robbo

Mine has always run @ 17psi regardless of which ECU I use [std or chipped].
Never thought of running the boost gauge from there. I put a T piece between the take off on the metal adapter and the pressure relief sensor. Still seems to pick up any faults.

Tony

Originally Posted by Grumpy

Mine has always run @ 17psi regardless of which ECU I use [std or chipped].
Never thought of running the boost gauge from there. I put a T piece between the take off on the metal adapter and the pressure relief sensor. Still seems to pick up any faults.

Tony

What that doesn't account for is any losses from the intercooler & hoses. This far more accurate for what's going into the engine hence the reason the ECU's boost sensor is on the manifold.
Temperature also affects the reading as does the loss and recovery from passing thru the CAC and from straight off the compressor it's the hottest and a far less dense charge.

Cheers

Andrew