Turbo Technics Hybrid turbo details.

[nutron]

The unit I have fitted and have done about 1700 miles with is a GT1752 effectively. Changes from standard:

1) Increased the compressor from 49mm to 52mm
2) Larger shaft to take the extra load
3) both bearings uprated

The turbine is unchange by the upgrade and the unit look identical from the outside.

Results from the change should be about 2bar (29psi) available from 2500rpm right up to the red line. Mine makes 20psi at 2000rpm which is as near as damed standard boost at that point. So you won't see any difference to performance below 2000rpm. Once you hit that mark though, boost rockets up and you can cleanly burn far more fuel to get plenty of clean power.

The ECU will throw a fit if you go above about 2bar with the boost, which is good because it means you can not over boost this turbo. but you should always allow the car to warm up fully before pushing it hard and let it spin down after driving BEFORE turning the car off.

Options available are:

1) send a working turbo for full modification
2) send a working turbo for service and a replacement core (should be faster turn around but they are having difficulty aquiring cores at the moment)
3) buy a new reworked unit (obviously very expensive)

Option 1 will cost you about 600 notes but may take a week or more. So either the car is off the road or you find one on ebay to send in like I did (100 quid max you should get one for).

In addition, you will need to change the oil and filter, new manifold studs and nuts, new manifold gasket, new EGR gasket, new oil feed pipe and bolts (the bolt into the block has an internal oil filter so it is important to replace or clean this). All that lot will add another 100-200 quid, depending on where you go.

You should also spend maybe the first 50 miles not pushing the turbo hard, to let it bed in. It looks just the same and has the same pipe fittings, so if you can take the old one off, you can put the new one on.

If you are interested, give them a ring and ask to speak to Pete. Some of the other staff are not very helpfull unfortunately.

Still waiting to run it with all my water/methanol running and see how much power/torque it makes but I got 195hp/290lbft at the road wheel (est 229hp/360lbft at fly).

Graph of boost shown below, obviously, the boost tails off where they let off the accelerator.

[dh.dti]

Karl,

How do the results compare to running the crd-t with standard turbo

[merikiito]

Thanks for the info. I will post up the specs for the one I have being done by AET Engineering when I get it so we can compare.The AET one is coming in at about £540 so a bit cheaper.

[nutron]

You couldn't make anywhere near the boost I now get with a standard turbo and it would peak and fall off. Does anyone have a standard boost graph?

[Harvey Smith]

My home made Vectra CDTi turbo cost £147.00 to make and that included a donor turbo.
I bought a Saab 1749VNT turbo on ebay for £77 delivered from some nice guys in Arbroath. I already had a 56 wheel and a local machine shop with the right experience machined the 49 cover to take the 56 wheel.
The car is mapped to run at 1.9 bar but it will do more and you can see the results below.

http://i52.tinypic.com/30aurs7.jpg

http://i52.tinypic.com/2u76agg.jpg

I now have a GT1756 VNT with a 60 wheel to try when I am finished getting the best out of the above turbo and if I find the 60 wheel too big I can go back to GT1756.

[nutron]

My only issues with your turbo Harvey is that

a) is has not been balanced and at 150,000 to 200,000 rpm it should be balanced to avoid potential catastrophic failure.

b) you did not uprate the bearings or shaft to cope with the extra torque on the turbo shaft.

I hope it lasts but I would not be suprised if it didn't. One of the guys from another site has a turbo on his old Volvo that he milled out in his bedroom with a remel. I would rather the piece of mind from having everything uprated, balanced and tested before it even goes near my car.

On the boost side, I am not sure how much boost mine would push. I have run 31psi on two sets of rollers but if I go higher the ECU throws a fit and tells me I have a leak. I was thinking of adding a potentiometer in the MAF system to reduce the amount of flow the ECU sees and see if I can push the boost a little higher.

I would like to add a larger turbine next, to see if the boost can be brought up faster, hopefully peaking at 30psi by 2000rpm.

[Harvey Smith]

a) You are entirely correct, my £147 turbo was not balanced but it was checked on a machine that apparently simulates 160,000 rpm or more and we have calculated that the bigger wheel is not likely to rotate at this speed.
The logic for going for bigger wheel was to cut down RPM and avoid overspeed.

b) Again you are entirely correct but this was a first venture in to an uprated Vectra turbo and it has several thousand miles under its belt now with capability well beyond 200 bhp and no failures.

I think you blew up the first turbo you got made professionally so have I been lucky or do we know what we are doing?

I hope it lasts but I would not be suprised if it didn't. One of the guys from another site has a turbo on his old Volvo that he milled out in his bedroom with a remel. I would rather the piece of mind from having everything uprated, balanced and tested before it even goes near my car.

I am quite well known for my Subaru turbos so the knowledge that goes in to them has gone in to my first Vectra turbo. I appreciate your concerns but I think I actually know what I am doing as indicated by my results and despite the very modest cost this is not a bedroom and dremel effort.
My next turbo, already built, 17/56/60 may be a stage too far in which case it will become a 17/56 but I am doing these things to see what works and so far everything is coming together nicely. The 17/56/60 does have a bigger shaft and bearing housings but I don't want to use that until I have finished with the development I am doing at present involving the 17/49/56. Modifying this first turbo means that instead of pulling from 1500 RPM the car is now pulling from 1700 RPM but it pulls strongly all the way to the red line whereas before there was never any point exceeding 4000 RPM and full boost is available just over 2000 RPM.

At RS Tuning you were running 2.3 bar which I thought was rather a lot. I was therefore surprised at your relevantly low torque figure because as you know more boost usually equates to more torque. My car is mapped to 1.9 bar and I have no plans to particularly exceed that figure. The limp home issue is identified and will be sorted when time permits so another run at RS Tuning in the near future is on the cards.

[nutron]

At RS I ran 31psi, where are you getting this 2.3bar idea from? Go check the graphs as I keep telling you to instead of using the random number generator on your scientific calculator.

The bigger wheel would rotate slower at the same pressure output but you aren't producing the same pressure, so you have no idea what speed it is running to. Supposed to simulate 160,000 rpm sounds like Regals supposed to be 210bhp claims...

You seem to be missing out on the purpose of the turbine. If you keep making the compressor bigger without increasing the turbine size, you put additional thrust loads on the turbo and increase lag.

The first failure was very irritating I agree and not what one would expect.

[merikiito]

Nutron and Harvey you both have a wealth of knowledge between you. Can we try and work together for the good of everyone? We can all learn by each others failures and successes and therefore be able to come up with the best results.

Rather than tit for tat can we not bounce ideas of each other to everybodies benefit?

I for one have to admire what both you guys have done as I am in awe of the knowledge you both have and the efforts you go to for power gains.

If have read some of the posts wrong then I apologise, all I can see at the moment tho is knowledge being wasted.

[Duncan]

Nutron and Harvey you both have a wealth of knowledge between you. Can we try and work together for the good of everyone? We can all learn by each others failures and successes and therefore be able to come up with the best results.

Rather than tit for tat can we not bounce ideas of each other to everybodies benefit?

I for one have to admire what both you guys have done as I am in awe of the knowledge you both have and the efforts you go to for power gains.

If have read some of the posts wrong then I apologise, all I can see at the moment tho is knowledge being wasted.

At RS I ran 31psi, where are you getting this 2.3bar idea from? Go check the graphs as I keep telling you to instead of using the random number generator on your scientific calculator.

2.3 bar is 33.8psi, so is that not splitting hairs a bit? He only 'over quoted' by just under 10%, so those comments maybe not really necessary?