Isuzu Trooper Owners Club UK™

Requin · Posted: Sat Sep 08, 2018 16:06 Post subject: blow off valve positioning

So while I was messing with the actuator on my 1998 3.0tdi, for the purpose of adding a regulator on it for a bit more boost(1-1.1 bar), I had this genius-dumb ideea.
What if I take the hose from the actuator and stick it on a blow off valve? The valve would blow at around 1.1 bar, thus working the same way the actuator does... but it would blow the extra pressure into the atmosphere.
I am also installing a boost gauge so that I can always keep an eye on my boost.
Is there any logical reason it would not work? It's been eating me up that I don't have a BOV on the Monterey.
Also, any suggestions on where to stick the hose for the gauge? Was thinking of putting it on the actuator hose, can't see a reason not to but I am more than open to ideas.
Thanks!
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Requin · Posted: Sat Sep 08, 2018 20:18 Post subject:

Point is to see what happens when you replace the actuator's work with a bov
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eithan h · Posted: Sun Sep 09, 2018 12:11 Post subject:

a diesel engine is regulated by the fuel unlike a petrol that is regulated by the the air it takes in so on a diesel you don't need to regulate the air you just need to control the amount of boost pressure so it doesn't blow the head gasket, if you remove the waste gate actuator then in theory the turbo will boost with no control on the exhaust side and could end up keeping the blow off valve open all the time and could end up with boost creep where it can't get rid of the excess intake pressure fast enough so the boost pressure goes up and up and then something gives...
and remember the blow off valve only works with a build up of pressure when the throttle flap shuts so it doesn't bend turbo vanes but on the 3.0l there is no throttle flap

the map sensor pretty much maxes out anyway at 200kpa which the standard turbo will produce easily so unless your going to alter the sensor theres no point in trying to get more boost out of it

Requin · Posted: Sun Sep 09, 2018 13:01 Post subject:

You are perfectly right on all counts, as usual.
My logic is as follows.
Engine is on it's way out, so is the turbo. So before I spend another bucket of gold on this black hole of a car, I was thinking I could have some fun with it and try some stupid ideas("genius").

One thing I still am in doubt about. The turbo can push 200kpa(meaning 2 bar) but it does not. It pushes about .85 if I am not wrong, because the actuator opens. So putting a regulator would stop the actuator from opening, well it would open a bit later. Thus giving more boost.
I see no other way to get more from the turbo. Maybe messing with the actuator rod but I have the standard one, without the nut on it so I can't use that. And the actuator rod, with the nut costs more than the regulator. Also, the regulator can be installed in the cabin, making it very easy to use.
Am I wrong? Can I get more boost into the engine in another way, other than messing with the actuator?
Thank you.
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eithan h · Posted: Sun Sep 09, 2018 15:23 Post subject:

turbo pushes out about 100 kpa as atmospheric is also measured by the map at 100kpa but the map sensor is maxed out at that so unless you alter the map sensor as well it wouldn't make a difference if the turbo pushed out 4kpa as the ecu will only inject for the 2 the map is reading.
to get more on a turbo diesel you need to fit a bleed valve to the actuator pipe not a dump valve to the inlet side. remember a dump valve is there to release excess pressure on the intake side i.e when a throttle flap shuts off the build up of air between the turbo and the flap is what causes the dump valve to go off, on a petrol yes by fitting a higher pressure one it increases the pressure between the turbo and throttle flap therefore when you accelerate again theres no lag as such and your off. but on a diesel theres no throttle flap so no excess pressure to build up so the dump valve will never go off.
turbo boost pressure is controlled by the exhaust side you need to make it boost longer before the waste gate opens to get the boost pressure up so either fit a bleed valve or a restrictor to the actuator pipe (subaru's use a restrictor in the pipe) which means it will take longer for the actuator to open allowing the turbo to boost more. but without altering the map sensor and possibly the ecu's fuelling map as i don't know what the ecu will cope with before it gets upset.

as a quick test just clamp off the actuator pipe and see if it goes any better but you do so at your own risk to the engine!!!

Requin · Posted: Sun Sep 09, 2018 15:43 Post subject:

Yes, that was the idea from my last reply. A bleed valve on the actuator hose. I get it why a bov would be pointless, still would love to try it out Smile

)
Would love to get someone to remap the whole thing but nobody here will touch it. It's like they are all scared of the car...

The sensor is maxed at what the turbo is putting out as standard(100kpa) or at 200? I am a bit confused since you mentioned both values for both turbo and map sensor.
In other words, what is the turbo putting out and at what value is the map sensor maxed out?
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eithan h · Posted: Sun Sep 09, 2018 16:10 Post subject:

map maxes out at about 200kpa think the highest i seen one read is 208kpa, the turbo is pushing out about 100 kpa as with engine off the map reads 100kpa which is atmospheric pressure

Requin · Posted: Sun Sep 09, 2018 17:09 Post subject:

So practically the map reads 200, half from turbo half from atmosphere.
Any simple way to fool the map? Something that will not require some scared guy that would do it but will not? Like I said, nobody will touch it...
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eithan h · Posted: Mon Sep 10, 2018 0:45 Post subject:

i would try and find a map sensor that can read more than 200kpa and wire it in, fit a boost gauge and then start restricting the pipe to the waste gate actuator and see what happens. as far as i know no one has done this yet so your in unknown territory lol

Requin · Posted: Mon Sep 10, 2018 8:04 Post subject:

Of all the Trooper enthusiasts, nuts and experts, not one has tried to get more kick out of their engine...
Well... I'll give it a go and see what's what.
Perhaps I should change my username to Nate. Deto Nate... Smile

)))
Guessing you wouldn't happen to have a suggestion as to what map sensor I should look for or what to use to modify mine?
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eithan h · Posted: Mon Sep 10, 2018 8:48 Post subject:

most people go the route of the tunit box on the 3.0l which alters the fuelling via the orps readings and everyone is scared of the fragility of the 3.0l engine

as for the sensor i don't know, a quick google of 3 bar sensors came up with this https://www.amazon.com/SENSOR-CUSTOM-12223861-MANIFOLD-PRESSURE/dp/B01NBDM6I9 which looks like the original but i don't know if it's right as it might be -1bar to +2 bar which is no higher than what they got at the minute

Requin · Posted: Mon Sep 10, 2018 10:00 Post subject:

Yeah, saw the tunit thing a bit ago but I am unsure... 400 £ for 40hp, IF it does get 40hp... seems like a total scam.
The map sensor from Amazon seems to be the right one, but it mentions nothing of the model it's made for and the thing costs about 50 usd and shipping is 110 usd. I will try and find something closer and with more details about it. What exactly did you search for? I gave a Trooper 3.0tdi 3bar map sensor search but came up with the standard one.
Was also thinking of adding 2 boost gauges.
1 would be tapped on the actuator hose, just before the bleed valve, and the other on the big hose that comes out if the intercooler. Thus, I can keep an eye on the entire thing.
Overkill?
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eithan h · Posted: Mon Sep 10, 2018 13:16 Post subject:

yes because the boost pressure in the actuator line before the bleed valve should be the same as the big pipe,

i just searched 3 bar map sensor i didn't put a specific car in so i could get more results

Requin · Posted: Mon Sep 10, 2018 13:28 Post subject:

Makes sense.
Did a search myself, even gave a few calls to some UK and other UE sites that sell 3 bar sensors.
Most can only read 2 bar positive and some didn't know...
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Requin · Posted: Wed Sep 12, 2018 11:29 Post subject:

So I installed the boost gauge, seems to be working.
At 3000rpm it pushes about 0.9 bar and starts dropping to 0.3 bar after 3000rpm.
But no point in messing with the beed valve since I don't have a map sensor that can read more than 2 bar... stiil searchin.
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I expect nothing. I fear no one. I am free.