Thread: Twin Turbo's or Hybrid

Originally Posted by c.h.i.e.f

Thanks dougal i thought it may have been the case with the wheel size etc etc i must get time to sit and read a turbocharger book..
Im just trying to find a turbo that will match the motor but still handle well over 20psi i might be looking at a vnt then
So you recon it could have failed due to other reasons and not due to getting pushed hard ?

Oh no, it was definitely overspeed that killed your 2052. They are a good turbo for up to 15psi on these engines, not 30psi.

Bush65 has done a lot of work matching Borg Warner turbos to the 4BD1, I believe he has one for his engine but I don't know if it's running or been tested yet.

The problem with VNT's is they don't make them in a good size for our engines. Ones from 3 litre and smaller engines are everywhere, larger ones can be found on engines 6 litres and up. But the 4 litre mark is a bit of a struggle. Toyota fitted a GT2560V to their 4.2 diesels in europe (commonrail too), but these turbos are rocking horse poo. Some nissan ZD30's had a GT2560V but it's apparently a first generation turbo that doesn't flow as much air as it's size would suggest. Later engines got a GT2052V.
The other problem is the compressor maps for VNT turbos aren't available. You can guess max flow by inducer size and take a stab at the rest of the map shape, but it's guesswork to a large degree.

sorry dougal i miss understood you before about the failure of my turbo and thought you ment it had nothing to do with overspeed for a second but yeah it was waiting to happen...
thanks for the info on the vnt's i personally want to go a bit bigger than the 2260 size even though Matt said he is having great success i was thinking if there was a larger one but obviously they are as you said pretty rare
i downloaded the borgwarner manual on there new range of vnt's awhile ago and they look like they have some very good design aspects and technology gone into everything to do with them but im just curious to see wether or not there worth buying or not not and if so what ones suit the isuzu.

as you have said bush65 will be the best bet

The GT2260VNT that Matt is running works quite well, heaps heaps better than the T25 he had on before. I have this same turbo for mine, (actually have a collection of them) and plan to use it (and the spares) until they die, then i may look into the borgwarner

From the L322 BMW?

iveco daily 3.0l

Where have you been sourcing these turbos from vern ? And how much roughly if you dont mind me asking ?

For the reasons dougal mentioned and the lack if tech info on the vnt ones I went with a BW. Havnt installed it yet, but I will do before and after dyno etc to get as much data as possible for people.

I got it from treadstone.

Double post..