Viewing: VW LT 35 turbo output.

**Harvey** · 05-10-2010, 12:21 PM

Can anyone tell me the power output of the VNT turbo fitted to LT35 around 2001/2002?

**turbonutter69** · 05-10-2010, 12:26 PM

Standard power is around 109 bhp.

**Harvey** · 05-10-2010, 12:42 PM

Not so good. I have just bought one, not a lot of money, with a view to increasing power output on my Vectra 1.9 CDTi/SRi that is currently 230 bhp/335 lbs.ft.

**turbonutter69** · 05-10-2010, 12:44 PM

Not sure about max power on that turbo?
Did anyone advise you to use that turbo?

**Harvey** · 05-10-2010, 04:47 PM

I was advised to get a BMW 530D turbo by an "expert" That is around 230 bhp on a 3 litre. Having examined one still on a 530 I concluded that getting it on the front of my Vectra might be a big, big job and need the radiator moving forward, even supposing it could make proper power.
I have seen a Land Rover with a VW VNT turbo, I think from an LT35 (I hope) and that was close to 260 bhp. Packaging looked like less of a nightmare for my restricted space.
Anyway I am now the proud owner of one of these so either I can mod it for proper power ie more than 230 bhp and it fits or I will have to sell it on.

**jarrus** · 05-10-2010, 07:59 PM

I think the best to use really would be something like a gt2256 or a gt2056, personally though the gt2256 would be better, that is what the 330d/530d uses,

**Harvey** · 06-10-2010, 12:20 PM

If I don't use the VW LT turbo that should be here by the weekend I will look at the above further. Thanks for the part numbers. Very useful. I concluded that getting the BMW 530D unit to fit in the space available could be a bigger job than I want and for that reason went for the VW unit which will need an inlet manifold fabricating and so on but I may not need to move the radiator. The complication with that is that I already have a large intercooler on the front taking up space that was previously vacant.

**jarrus** · 06-10-2010, 01:08 PM

Quite possibly, did you move your radiator backwards to fit the intercooler?

Also why do you need a custom intake manifold?

**jarrus** · 06-10-2010, 01:13 PM

What is the vw turbo off, a golf?

**Harvey** · 06-10-2010, 08:47 PM

No. An LT35 is a VW Transporter Van. The turbo and manifold should be here before the end of the week and I can then give it a good assessment and decide what is necessary and if I will be able to boost its power to do what I want. The existing turbo on the car is off a Saab but that is basically the same as the Vauxhall VNT turbo (Garrett I think) and all I have done is put on a 56 diameter compressor wheel in place of the OE 49 diameter wheel and then turned the compressor cover to suit and bored it out a bit at the compressor outlet. I can perform similar surgery on the LT35 turbo but I am hoping it will be less of a nightmare to fit than the BMW 3 litre diesel for the physical packaging. This all assumes it has a bigger exhaust housing so I have potential for more power for the effort that will go in to it.
The water radiator is still in the OE position but the twin fans are quite close to the turbo heat shield. When I fitted the large Subaru STi FMIC core I moved the air con condenser back a bit to allow the front mount to have enough space.
A custom manifold is needed for two reasons.
1. The 1.9 Vauxhall turbo exhaust housing is integral with the exhaust manifold.
2. The turbo exhaust inlet is located between cylinders 3 and 4 and for best gas flow and least back pressure it should be located between cylinders 2 and 3 ie. cylinders 2 and 3 will travel equally and cylinders 1 and 4 will travel equally.

I will try and get some photos at the weekend.

**jarrus** · 06-10-2010, 10:43 PM

So you've made a hybrid turbo then? So I'm guessing the turbine side is a gt17 then? If that's the case then an upgrade isn't really worth it, how much power and torque do you have now? And at what RPM's do they peak? And what are you aiming for?

**Harvey** · 07-10-2010, 12:41 AM

I don't know anything about part numbers. It is basically the OE Vauxhall turbo for a Vectra CDTi/SRi MY 06 but I have fitted a bigger compressor wheel and machined the Vauxhall cover to take that. I already build turbos for use on Subarus, (TD05 18G and 20G and TD05-06 20G) but obviously they are petrols and this diesel is VNT.
Why is an upgrade not really worth it???
I am going to my bed now but I will try and post the rolling road graph with all the relevant info showing RPM/torque/bhp, tomorrow or before the weekend.

**jarrus** · 07-10-2010, 07:57 AM

It totally depends on what your goals are at the end of the day,

The rolling road graph for your car would be ace as this is a more clear indication of what's going on that roar numbers
A 56 compressor wheels should be good for over 240 hp but then again if you are using a machined standard compressor housing then there maybe issues that haven't been accounted for before,

The case might be that a good upgrade would require you fitting a compressor housing from the gt2256 (the GT22 is the frame size which is the size of the turbine side and 56 is the size of the compressor side) and these are garrett turbos and If you buy a new turbo make sure that it has a 'V' on the end of the part number as this depicts a VNT rather than a wastegated turbo

**Harvey** · 07-10-2010, 10:08 PM

Thanks for all the information above.
If you can expand on this I will mull it over. When the turbo project started my main concern was there was enough meat in the O/E cover to take the 56 wheel in place of the 49. When the job was finished I was surprised how much meat was left.
Until now I was not familiar with the numbers of these garret turbos but I have done a bit of research and if I have it right here is a bit more info.
The 1.9 litre Saab and Opel are frame 17 so O/E they have GT1749 if such a thing exists??? So I have made that into a GT1756 I guess and with all the other mods it has gone well enough for 230 bhp and 335 ft lbs on the same rolling road it did 158 bhp and 230 ft lbs before any modding started.
Now the VW p. no. for the turbo I hope arrives tomorrow is 721-204, I hope. Now I am hoping that is a 2256 or at worst a 2056. My logic is that either of these turbos have a bigger shaft and vane system so even with the same 56 compressor wheel there will be potential for more power.
Do you know what cars/engines run 20 or 25 frames and is the 22 frame on Range Rover, hence the Land Rover connection where I first got the idea???

**Harvey** · 07-10-2010, 10:34 PM

Before anything was done to this car it did 158 bhp/230 ft.lbs on the same rollers.

**jarrus** · 07-10-2010, 10:37 PM

the audi 2.5 tdi v6 ran a gt2052 rather than the 56, and bmw 330d ran a gt2256,

from what I can gather, on a gt2056v you should be able to get 260 hp,

do you have that graph to hand?

**jarrus** · 07-10-2010, 10:41 PM

I would say try a gt2256 if you want big power mate, that should give you 280 hp with no problems, also some more torque up the rev band, i've seen these wrung out to 300 hp on VW 1.9 tdi's (the older engine in the mk4 then non PD the VP which is like an electronic VE pump)

can your injector supply the fuel though and your engine internals take the punishment?

what other mods do you have as well mate?

**jarrus** · 07-10-2010, 10:47 PM

apologies, it's a gt2259v, just looked it up, so it has a bigger compressor wheel then...

**Harvey** · 08-10-2010, 12:09 AM

Jarrus: Can you just clarify what has a gt2259 and can you confirm the VW 721-204 is either 2256, I hope, or 2056. My concern is that 1.9 litres in a daily driver will have a limitation at some point as to what is practical so what might work well on a 3 litre may not work so well on a 1.9 litre. Once I have tried out the VW turbo either my assumptions will be right or I will have to have a go at a third turbo. I may well get a little bit more out this present one.
From standard the car initially had an airbox and oil breather mod. I doubt they made any difference of consequence. I also fitted a K+N panel.
This was followed by a hand made exhaust which is as quiet as the original except on WOT when there is a little bit of a rasp.
The inlet manifold was replaced. A difficult job. The swirl flaps were jamming and the link rod popping off. I now know this is a common fault. At this point on Scooby Clinics rolling road we had 194 bhp and 294 ft.lbs. using a CK Speed tuning box to control fuel and the car was reasonably clean. Fantastic value for money.
I then put on the turbo that is still on which we can now call GT1756 along with a Hybrid front mount intercooler core for a Subaru Classic WRX/STi.

I then took the car to Celtic Tuning in St. Austell as I understood they could live map but that is not the case. After their mapping the car was very smokey and on WOT around 4000 rpm the CEL would come on and the car was in limp home mode. Not a complete disaster as switching the ignition off and back on again cleared the fault. This was showing on my data logger as PO100 Mass Air Flow Sensor. Celtic told me the MAF needed replacing which I disagreed with but replaced it with a new one immediately only to have the same fault. After some delay the car went back to Celtic, round trip 860 miles. The excess smoke was cured, the CEL still comes on as above but the car does not go in to limp home mode and the boost control is inconsistant. Celtic say this is not a mapping issue but I think it is.

On my OBD log the MAF sensor appears to max out at 172 g/s but I don't think this is restricting power at present just that the ECU can't read beyond that point and for some reason the boost is flat lining at 255 kpa even although it will momentarily pull 1.8 bar and drop back to anything between 1.45 and 1.6 bar. A sudden application of the throttle will get it to 1.8 bar but it fairly quickly gets pulled back, usually 1.5 or 1.6. The plan had been to set the boost to 1.9 bar but that was not achieve at Celtic. Having checked with Bosch Technical the MAF sensor is digital so it is not a simple matter of swapping as it would be with something reading 0-5v and the MAP sensor is 3 bar so running 2 bar as far as pressures are concerned should not be an issue.

Just tonight after a lot of frustration over many weeks I think I have deleted the EGR valve without the CEL coming on but I reserve judgement on that until I have driven the car for a few days. I want to get to the bottom of the MAF and MAP sensors and anything I can do to get more air in to the engine should improve things. I don't know how far the injectors can go but I know I can still get excess fuel so there is a little bit more to go but the turbo might be the limiting factor. I plan to port the previous inlet manifold and remove the tumbler flaps to see what happens. I may also remove the throttle flap at the beginning of the inlet manifold. I am not sure what it does but it might be something to do with the stability control. I just want to see what will happen without getting warning lights, limp home mode etc. Above all the car has to remain tractable and pleasant to drive in town. Fitting the bigger compressor wheel lost very little in driveability and I don't want an engine that needs 2000 rpm before it will go when originally it would pull from 1500 rpm.
When tuning Subarus it is relatively easy because we remove the original ECU and replace it with an aftermarket that makes adjusting ignition, fuel and boost relatively straight forward. Unfortunately playing about with this I am a bit in the dark and there are so many sensors feeding information back to the ECU it is not clear what the effects of a particular action might be.

Any input on any of the above greatly received

**Harvey** · 09-10-2010, 06:06 PM

Well that did not quite go as to plan and I have spent £200 on a turbo that is not exactly what I thought I was getting. I thought I was getting a VW 741-204 which would be a 2056 or 2256 but what I have is a 741-457 and that is stamped GT2052. The exhaust side is bigger than the existing Vauxhall turbo exhaust but the design is so different I am not sure I can utlilise it and while the snail is slightly bigger diameter than the OE Vauxhall item the wheel is obviously a bit smaller, 52 compared to 56.
I will strip it down tomorrow and assess the possibilities.

***HDi fun*** · 09-10-2010, 07:10 PM

Is the vehicle you're discussing fitted with a DPF?

**Harvey** · 09-10-2010, 07:28 PM

MY06 Vectra CDTi SRi. Bosch EDC16. This vehicle was just prior to the DPF equipped cars which had the EDC16+.

***HDi fun*** · 09-10-2010, 07:52 PM

That's fortunate.

My 406 HDi 2.2 was the first UK car to be thus equipped and this was back in 2001.

Needless to say at that time the systems were quite crude, if effective.

Despite this, Celtic managed to tune sympathetically and I didn't incur problems. In fact, the regeneration cycle used to be quicker after the remap, possibly due to slightly higher combustion and exhaust temps overall.

I asked the question on account of the fact that the warning light might have been DPF related. Clearly not, though, 'cos your car doesn't have one.

Keep us posted

**jarrus** · 09-10-2010, 08:19 PM

Make a hybrid with your vaux turbo, (sorry I haven't replied in ages)

A gt2056 should make 260 hp, but a gt2259 can make over it's stated 280hp

You will find you may loose a bit in the low end to make some more torque up top, however you will find that will still have plenty of torque left anyways so I wouldn't worry about it,

Have you considered using LPG as well?

**Harvey** · 09-10-2010, 10:07 PM

I have been told the EDC16+ equipped Vectras with DPF have more tuning potential but I am not sure I believe that.

I am not interested in LPG as the car is a load carrier and I can't be bothered with a cylinder but I have also thought of nitrous oxide (just for a laugh, pun intended) and the cylinder would mount easily behind the passenger or driver's seat. Not sure what I would tell my Wife that was as it is her car.

Making a Hybrid between the 2052 and the 1756 or whatever it is now the OE turbo on the Vectra with the grafted on 56 diameter wheel now has to be a possibility but I go back to my concerns that I am running 1.9 litres and the disparity between my 17 exhaust housing and the already big 56 diameter wheel. I will mull it over.