Thread: TD5 Boost Limit Box group buy

Originally Posted by Blknight.aus

now yovue got me interested...

Given that the turbo is wastegated at 19 PSI as standard (at least on the Defenders) and the engine is easily capable of that without excessive risk whats the advantage of lifting it to only 18.5....

more importantly....

Define AFR...

IF your definition is the same as mine..

care to explain how you "set" the AFR of a diesel?

AFR was terminology used to try and explain.

May be it would have been better if i said adding boost can help get rid of smoke from a chipped overly diesel smokey engine loool.

On the TD5 the measured airflow amongst others is used to calculate injection ammount, so this is why i used terminology AFR or Air To Fuel ratio.

Here is an intresting post in diesel stoichiometric AFR

GM Diesel V6 for Commodore - FinalGear.com Forums

And a intresting pdf here

http://www.ornl.gov/~webworks/cppr/y2001/rpt/122001.pdf

both those links are nice and dont tell me anything I didnt already know and more to the point dont answer the question.. allow me to rephrase..

your box tricks the ECU into thinking it has less boost than its got there for letting it turn the wick up yeah

If it thinks its got less boost than its got its not going to open the wick as far as it could as it wont be reading sufficient boost pressure to allow full fuel into the system, after all that's part and parcel of why the boost pressure sense is there in the first place as it prevents polution and more importantly saves fuel,

if you have to have the ECU remapped for your little box to take full advantage, why not just remap the ECU to do what you box does in the first place?

IF your little box stops the ECU from putting the engine into a protected mode by telling the ECU lies about whats going on isnt that essentially circumventing a designed safety system? (safety as in this is what the engine can safely handle)

Isnt bypassing safety stuff generally bad?

Originally Posted by Blknight.aus

your box tricks the ECU into thinking it has less boost than its got there.

Yes

Originally Posted by Blknight.aus

If it thinks its got less boost than its got its not going to open the wick as far as it could as it wont be reading sufficient boost pressure to allow full fuel into the system, after all that's part and parcel of why the boost pressure sense is there in the first place as it prevents polution and more importantly saves fuel,

The box only comes into play just under the standard boost cut limit so 99% of the time the car pressure sensor is reading correct and standard figures.

Originally Posted by Blknight.aus

if you have to have the ECU remapped for your little box to take full advantage, why not just remap the ECU to do what you box does in the first place?

I can raise or remove the limit in the ecu that the boost cut comes in the mapping but some customers dont have my maps on so i can adjust theres.

Originally Posted by Blknight.aus

IF your little box stops the ECU from putting the engine into a protected mode by telling the ECU lies about whats going on isnt that essentially circumventing a designed safety system? (safety as in this is what the engine can safely handle)

Yes but its not actualy a bypassing or circumventing because the boost cut limit is still there its just raised slightly
,exactly the same as the pluse width modification on your chipped TD5 but who says its safe to do that ?? and that the engine can handle it.

Originally Posted by Blknight.aus

Isnt bypassing safety stuff generally bad?

yes but its not a total bypass, a bypass would mean it was totaly removed from the system.


Regards Pete

Right, now Im on net with you...

what your saying earlier on and whats in your links to your page didn't quite gell with my version of the way things work, the devils in the details...

I still think that the box shouldnt be required IF your Td5 Is remapped correctly Mine pushes through to 23+psi if Im being nasty enough to it

That said If your having problems with a TD5 remap thats causing an overboost cut out then this is the box you want...


My initial thoughts were along the lines of it was a fairly simple type resistor in a box made pretty that a lot of shifty sites flog to wanna be rice boys who know no better that is just a resistor that makes the ECU think the engine is still cold so it runs the mix a bit richer. Doing this on a TD5 if you get it wrong has the potential to do very bad things.

IF its one that has a pass through for normal operation and only comes into effect when its needed then all cool. I personally still wouldnt mind an eyeball of the logic map and schematic of it just so I can satisfy myself that it does what it does in a smart way and isnt the equivelent of cutting the waste gate actuator rod on a tdi.. (seen that before)

Originally Posted by Blknight.aus

Right, now Im on net with you...

what your saying earlier on and whats in your links to your page didn't quite gell with my version of the way things work, the devils in the details...

Im sorry if my text or explnation was misleading to you.

Originally Posted by Blknight.aus

I still think that the box shouldnt be required IF your Td5 Is remapped correctly Mine pushes through to 23+psi if Im being nasty enough to it

Have a look at your live maf reading and inlet pressure when you are creating a measured boost of 23psi, you may be suprised.
23psi is 259Kpa and is over the ecus set limit of 242Kpa max.

Originally Posted by Blknight.aus

That said If your having problems with a TD5 remap thats causing an overboost cut out then this is the box you want...

Thank you,
ill add to say that the map on the car is normaly irelevent to weather the needs to be limit rased or not because its normaly only when mechanical adjustments are made to the wastegate that the pressure goes over the threshold.

Originally Posted by Blknight.aus

My initial thoughts were along the lines of it was a fairly simple type resistor in a box made pretty that a lot of shifty sites flog to wanna be rice boys who know no better that is just a resistor that makes the ECU think the engine is still cold so it runs the mix a bit richer. Doing this on a TD5 if you get it wrong has the potential to do very bad things.

No i can confrim that there is no resistors even in the curcuit,admitingly the cirucit is not very compex as circuits go but there areno resistors used at all.

Originally Posted by Blknight.aus

IF its one that has a pass through for normal operation and only comes into effect when its needed then all cool. I personally still wouldnt mind an eyeball of the logic map and schematic of it just so I can satisfy myself that it does what it does in a smart way and isnt the equivelent of cutting the waste gate actuator rod on a tdi.. (seen that before)

The schematic is not available sorry,The box is not very complex as said and it does let about 99% of the standard readings go to the pressure sensor, it only comes into play when the sensor outs a signal very close to the boost cut level of 242kpa.

If the box is fitted to a car and NO mechanical adjustmenst are made it wont make any difference.
The box as said for people who want to run higher mechanicly adjusted boost than standard without having the problem of boost cut under load.

Regards Pete

Originally Posted by B-A-S

Im sorry if my text or explnation was misleading to you.

Have a look at your live maf reading and inlet pressure when you are creating a measured boost of 23psi, you may be suprised.
23psi is 259Kpa and is over the ecus set limit of 242Kpa max.

according to google, my computer converter, my calculator, my tyre pressure gauge and my mobile phone converter 32psi is only 220 KPa...

Originally Posted by B-A-S

The schematic is not available sorry,The box is not very complex as said and it does let about 99% of the standard readings go to the pressure sensor, it only comes into play when the sensor outs a signal very close to the boost cut level of 242kpa.

thats not the right answer dude...

In a very rare occurrence.

Im going to rebuke my stand... I don't recommend this box, IF you have over boost cutout problems. Find the actual cause and fix that instead.

I dont endorse aftermarket butchery that I cant dissect for functionality and other potential problems...

For those who would like a full explanation I am happy to do so in PM's

Originally Posted by Blknight.aus

according to google, my computer converter, my calculator, my tyre pressure gauge and my mobile phone converter 32psi is only 220 KPa...

Yes it is.

you said you were running 23Psi which is 158.5794Kpa !!!
PLUS atmospheric pressure of 100Kpa
This equals 258.5794Kpa which is over the 242Kpa ecu limit.

And yes before you state it 242Kpa minus 100Kpa atmospheric = 142Kpa or 20.59536Psi.
So why do i sell the box to help you run a steady 18psi if the limit in the ecu is 20.59536Psi.
Answer = because you cant run it long eniough without boost cut

Now you have me confused to which pressure you are actualy running.

Re the PM statement , post your explnation here since you braught the subject up.