GTB1756VK - Some questions !

[Hdisw]

Hey people i have some questions and i wish you could help me !

I've installed an GTB1756VK in my estate hdi ..

I had a leak in the exhaust header at the time and the turbo was doing 30 psi ..

Now that the leak is fixed and it's doing 30 psi also .. i have the GT15 wastegate .. i think it only does 24/25 psi max.

Previously i didn't listen to anything but the leak .. now i hear some whining and i guess it's from the wastegate.

Maybe the wastegate is the problem ?

hug !

[Poodle]

The GTB-V doesn't need a wastegate, it's a vnt turbo that you should be controlling with the ecu.

[Hdisw]

It can be controlled by pressure with a wastegate, that's the way i'm doing it and other people done here in portugal with other turbos like 1852v and 1749vb's and so on ..

To be controlled by the ecu i think it needs the HDi 110 ecu and the N75 valve ..

Anyway i'm going to check my wastegate if it's working good or not .. but guess not !

[darrenjlobb]

It will work as you say with the wastegate accautor. However, it would work better using a orignal VNT boost can with the diaphram reversed, it has a softer spring / more travel. Either way, you need to reduce pre load / mbc pressure as its obviously un able to overcome it at the moment / over boosting...

[Poodle]

Well yeah it can, but then you may as well spend £50 on a td04 rather than shelling out for a vnt, it completely defeats the object of running variable geometry. Unless you mean you're using the old pressure actuator to control the vnt mechanism..?

You need the n75 valve, can use the one that was controlling the egr valve. The 110 ecu is exactly thesame as the 90bhp one, just has different maps, any decent mapper should be able to enable vnt control on the standard 90 ecu afaik.

[Dum-Dum]

Sounds like it could be an incredible turbo.

Anyway if your using a GT15 boost actuator on the VNT mechanism instead of the original vacuum actuator you need to turn it round the other way as the vacuum actuator leaves the vanes open with no vacuum then pulls them closed with ECU fed vacuum whereas with a boost actuator you need to have them pulled closed with no boost and then pushed open when the actuator receives boost.

I set my turbo up using a length of hose to the actuator with a tyre valve glued into the other end and then connected a bicycle tyre pump with a good pressure gauge to it and used it to check the travel (see the below video).




Some people run a manual ball and spring boost controller in the line to the actuator so it doesn't start opening till a certain boost threshold as all the actuators I have tested start moving at about 5psi.

[darrenjlobb]

Well yeah it can, but then you may as well spend £50 on a td04 rather than shelling out for a vnt, it completely defeats the object of running variable geometry. Unless you mean you're using the old pressure actuator to control the vnt mechanism..?

You need the n75 valve, can use the one that was controlling the egr valve. The 110 ecu is exactly thesame as the 90bhp one, just has different maps, any decent mapper should be able to enable vnt control on the standard 90 ecu afaik.

Lol, you have obviously never driven / rode in a diesel with a VNT on a boost can then? Comparing a td04 to a vnt on a boostcan is like comparing a 1.1 TU to a gti6....

Running an ECU does help with surge / mpg and easier on the turbo during cruise..but it wont make mower power, or spool up any faster. They are a monster to drive on a boost can just as they are on an ecu...once you run a VNT you will never run a WG turbo ever again. Its certainly not pointless / might as well run a td04....

Why "waste" excess exhaust gas past the turbine via the wastegate when you can just run a turbine that can flow more gas in the first place and "close up the vanes" to utilize the turbo in the lower revs....


Watch my audi v6 mtdi / 306 mtdi build videos to see how I modify the boost can, takes 5 minutes, and works perfectly.

[silverzx]

Sounds like it could be an incredible turbo.

Anyway if your using a GT15 boost actuator on the VNT mechanism instead of the original vacuum actuator you need to turn it round the other way as the vacuum actuator leaves the vanes open with no vacuum then pulls them closed with ECU fed vacuum whereas with a boost actuator you need to have them pulled closed with no boost and then pushed open when the actuator receives boost.

I set my turbo up using a length of hose to the actuator with a tyre valve glued into the other end and then connected a bicycle tyre pump with a good pressure gauge to it and used it to check the travel (see the below video).




Some people run a manual ball and spring boost controller in the line to the actuator so it doesn't start opening till a certain boost threshold as all the actuators I have tested start moving at about 5psi.

I like what you've done there Chris.

[Poodle]

And you have obviously not read my post properly Darren lol. Seems i've got the wrong end of the stick, I took the op literally when he said he was using it with the old wastegate, my bad. I should think you'd agree that running a vnt with a wg would be about as pointless as it gets.

Yeah, quite, just seems daft to bodge it on with a boost can when you could just control it properly, especially considering he's already got all the hardware in place. Each to their own though I guess.

[darrenjlobb]

And you have obviously not read my post properly Darren lol. Seems i've got the wrong end of the stick, I took the op literally when he said he was using it with the old wastegate, my bad. I should think you'd agree that running a vnt with a wg would be about as pointless as it gets.

Yeah, quite, just seems daft to bodge it on with a boost can when you could just control it properly, especially considering he's already got all the hardware in place. Each to their own though I guess.

To be fair, even if i was running EDC15, I would run a boost can...or if i wanted ecu would likely just do it with an arduino / something else, as otherwise your relying on someone to "map" it to work as you want it...im yet to ever see someone map a car how I want it...let alone map a VNT how I want it...its just always a disaster...

Its easy enough to setup an arduino, even more so given the program is freely downloadable for basic VNT control, but even then, its so much easier to boost can it in alot of cases, and it often wouldnt matter at all. Depends on milage / what the cars for at the end of the day. That said, 20k seems to be no hassle at all with a boost can, and even if they fail every 20k (which clearly they wont), theres nothing like a turbo failure for an excuse to get a bigger / better blower!!!

[darrenjlobb]

p.s. Im pretty sure the OP means "wastegate actuator" when he says "wastegate" but correct me if im wrong, thats how i read it anyway.

[Dum-Dum]

p.s. Im pretty sure the OP means "wastegate actuator" when he says "wastegate" but correct me if im wrong, thats how i read it anyway.

TBF I read it as he was running a wastegate on a VNT initially too but decided that was stupid and re-read it remembering that english isn't the first language of the OP and took the other meaning from it.

[Poodle]

Fair enough, as Steve will probably verify; personally i'd just keep bugging the mapper until they got it right lol. Can certainly see your reasoning there though, and tbf if it works...

You're dead right there, that would have been the obvious assumption. I'm not much good at assumptions though, hardly surprising when you look at some of the hdi threads/pms that get sent my way. I wouldn't be surprised to find out a nooby had heard about the new vnts being top drawer but the vnt mech being difficult and made the jump to "i'll just use it with a wastegate", that's actually a fairly intelligent thought process compared to some i've seen recently (look at the "bad times... what now" thread if you want a laugh).

[dashmader]

I am also from PT (Azores) and i have been using from some years the vnt on my 306 controlled by ecu

[Hdisw]

solved !