Hybrid Turbos by Dan Jones. Article No 5 in a Series by Experts in the Industry

[IC]

This latest article is by Dan Jones of Turbo Technics. Turbo Technics are a long established company who are one of the leading authorities in the UK on Hybrid Turbochargers


Hybrid Turbochargers.


What is a Hybrid Turbo?

A hybrid turbocharger combines the quick boost response required at low
engine revs, with the extra air-flow capacity needed for more power at
higher revs - with excellent Turbo Technics reliability.

Hybrid turbochargers are not a new idea. Turbo Technics started
producing hybrids as long ago as 1985, and today continues to lead this
specialised field. A language has even evolved to describe the
components employed in hybrid turbos - words such as cut-back, 360°,
screw-down and quick release.

For most road going cars, a standard specification, good quality Service
Exchange Turbocharger is sufficient. Hybrid turbos only become necessary
when significant performance improvement is required, normally on a
modified engine. Most hybrid turbochargers will look identical to
standard units from the outside. The changes occur inside, by using
different aerodynamic configurations, both in the compressor and turbine
housings.

As a Garrett turbo main dealer (since 1986), Turbo Technics are in a
unique position to choose from a comprehensive range of components. This
allows our engineers to "blueprint" turbocharger components to achieve
the desired characteristics needed for a particular application.
Obviously there are limits, but this ability sets Turbo Technics apart
from others in producing very effective hybrid turbos.

Most turbocharged engines respond well to increased boost pressure, but
only if the engine is modified to capitalise on the change. The same can
be said of turbochargers. A hybrid turbo on a standard engine may offer
a small benefit, but will be more effective on a modified engine.
Unfortunately, increasing the boost pressure also significantly
increases the internal loading within the turbocharger. In order to
compensate for this, a "screwed down" thrust bearing is sometimes used.
This prevents the bearing from "lifting" at high load which can lead to
oil starvation and component failure.

To continue up the hybrid ladder of performance, a "360°" thrust bearing
is used. This is an entirely new bearing, manufactured by Turbo
Technics, and originally developed for our competition customers, such
as Ford Motorsport. It has a greater bearing contact face, to withstand
the high loads, which would otherwise destroy a standard bearing very
quickly.

Turbo Technics will occasionally specify a "cut-back" shaft wheel. This
is the main exhaust-driven turbine wheel inside the turbocharger. To
limit its speed to acceptable, reliable levels, and to improve the
airflow, the blades are "cut back". This is a very high precision
machining operation, requiring highly accurate grinding and balancing.
The Turbo Technics designed and manufactured VSR balancing machine
ensures that exact limits are achieved every time, regardless of the
vehicle to which the turbo will be fitted, from the standard Mondeo
turbo diesel to a full works Group A' Escort Cosworth.

Other ways in which a hybrid turbocharger can enhance an engine's
performance is by improving response, or reducing turbo lag. By
designing a more efficient turbocharger compatible with the engine's
characteristics, Turbo Technics offer hybrid turbos which can transform
a car's driveability.

This document may not be copied or edited for use in a publication or on the world wide web without
prior permission.

>What is a Hybrid Turbo?
>
>A hybrid turbocharger combines the quick boost response
>required at low
>engine revs, with the extra air-flow capacity needed for more
>power at
>higher revs - with excellent Turbo Technics reliability.

I have to disagree with that. A hybrid turbo is nothing more than a turbo made using components from 2 or more turbos. That's it!!! It really is that simple in it's definition.

Although many people try to make hybrid turbos so that they have the characteristics described above, it does not necessarily follow that this is always the case. You may have a hybrid turbo that has the same response low down, but improved top end. You may want a turbo that has same top end but better bottom end. Whatever the characteristics, if it's made from two or more different turbos and components, it's a hybrid. You can in fact make a hybrid turbo that has worse characteristics than a normal turbo, and although it sort of defeats the object, it's still a hybrid.

Adam.

[Dan F]

Hi.

I thought a hybrid turbo is one that is simply not an off-the-shelf item from a manufacturers catalogue.

If you can source an off-the-shelf item that will fulfill the extra needs of a modded engine then so much the better.
However hybrids are generally used at the very top end of the scale by people/teams who want to maximise everything about the turbo/turbos fitted to a car and they therefore hybridise; Compressor wheel from this one, turbine wheel/housing from that one, compressor housing from that one, or machined out etc etc etc. All to suit the one off, bespoke application they are building it for.

As soon as you start to manufacture 'a hybrid' of a certain spec, then surely at that point it is now an off-the-shelf item, and could be given its own designation.

Regards,
Dan.

[sholtby]

Thanks to Dan for taking the time to write that article.

What I'm interested in is if the Turbo Technics hybrid turbo is better than a 19T as a performance upgrade when fitted along with custom tuning?
We have only heard from one person on this forum who has fitted the TT hybrid and his dyno results were not over impressive. Please dont let us argue about this again. Do we have any other data from other cars fitted with this turbo?
The 19T turbo is very commonly used and seems to give excellent results other than when it is fitted without custom software when it has a tendancy to bend the con rods due to high boost at low revs ie excessive torque.
The only advantage I could see from fitting the TT hybrid was that I wouldnt need to replace the downpipe/cat as the fitting would be the same. This is a considerable cost saving though.
In my case I looked at what had been acheived by others and fitting a 19T seemed the best choice.

Simon

[pyaap]

>We have only heard from one person on this forum who has
>fitted the TT hybrid and his dyno results were not over
>impressive.

Hi Simon,

I think you'll find that the person in question wanted the car to be mapped according to his specific needs and was not going for all-out performance (I'm sure he'll correct me if I misunderstood his requirements) so the TT hybrid is not actually being stretched to its limits by any account. I think the majority of people who go for 19Ts do that because they really don't know of any alternatives and in some cases are certainly advised against them. There is always an element of reaching into the unknown with something completely new, and tuning companies rather stick with methods / equipment they are used to as it makes it a lot easier to work with.

I would also like to add that having been in the car in question, it certainly is no slouch - the mid range is VERY impressive.

[adieu]

Ok I'm the one with the Hybrid. You say my results wern't great but I gained 22Bhp with a standard map on my car and the Hybrid. Now with the map sorted I still have the extra 22bhp (running 1.1bar) but loads more torque and all at lower revs( so no having to thrash the engine to get the best) I can see the results and feel the results. I'm also safe in the knowledge that I have a Turbo that will out live my engine. My car is mapped for everyday driving with a bit of fun when required. Yes I could have it mapped to run a stupid amount of boost and maybe get 50-60bhp more but at what cost? A new engine every 10k?

As Dan states a Hybrid from TT is built to last and out perform any other Turbo of similar type.

With effect to this does a 18T or 19T need a dump valve?

Answer: YES

Does my Hybrid?

Answer: NO

Why?

Answer: Because it's built stronger, better and made to last!

Regards

Iain

[pault5]

>Ok I'm the one with the Hybrid. You say my results wern't
>great but I gained 22Bhp with a standard map on my car and the
>Hybrid. Now with the map sorted I still have the extra 22bhp
>(running 1.1bar) but loads more torque and all at lower revs(
>so no having to thrash the engine to get the best) I can see
>the results and feel the results. I'm also safe in the
>knowledge that I have a Turbo that will out live my engine. My
>car is mapped for everyday driving with a bit of fun when
>required. Yes I could have it mapped to run a stupid amount of
>boost and maybe get 50-60bhp more but at what cost? A new
>engine every 10k?
>
>As Dan states a Hybrid from TT is built to last and out
>perform any other Turbo of similar type.
>
>With effect to this does a 18T or 19T need a dump valve?
>
>Answer: YES
>
>Does my Hybrid?
>
>Answer: NO
>
>Why?
>
>Answer: Because it's built stronger, better and made to last!
>
>Regards
>
>Iain
so a turbo with a 'dump valve', actually the 19t has recirculating valve often refered to as a cbv is an inferior turbo unit! come on iain thats absolute twaddle! you can do better than that!
paul

[adieu]

>so a turbo with a 'dump valve', actually the 19t has
>recirculating valve often refered to as a cbv is an inferior
>turbo unit! come on iain thats absolute twaddle! you can do
>better than that!
>paul

I have no dump valve at all not even a recirculating one.

I feel that for performance a Hybrid is the only way to go! My turbo is stronger and will out last any 19T! And with the right mapping can and will out perform any 19T you want to throw at it. The hybrid I have fitted is far superiour to any 19T end of story.

But as I have said already my car is mapped to MY driving style and MY needs before you start quoting my perfomance figures.

Regards

Iain

P.s I'm no expert on Turbo's I just know what I feel everytime i drive my car. Maybe Dan can let us know the main diffrences betwwen the 19T and my Hybrid.

[pyaap]

Hi Paul,

I also feel it may be worthwhile noting the reasons why a 19T needs a recirculating valve and the hybrid does not. This has been discussed at length by Dan Jones in a previous post.

[adieu]

Here ya go the post made by Dan from TT:

The turbo is built to handle 22psi all day. While the 19T is a good turbo for a standard car, i would not recommend it to be used for running high boost. Yes, they come with a 360 degree thrust bearing as standard, but it really isn't up to the job of handling much more than standard boost. There is also the problem of the old comp wheel design and it's narrow working range.

To be honest, it is nearly impossible to use a standard turbo as an uprate in place of another standard turbo. While the 19T is the closest match you would find with regards to size (although it is still quite a bit smaller), it is not built to handle high boost pressures, nor is it specifically designed for the job you want it to do. It would be nearly impossible to put a warranty on a standard unit being run above its recommended boost pressure. We can offer a two years warranty with our hybrids.

I would just like to point out, as well, that it has been mentioned that a Standard unit can run up to 26psi. This is true of most turbos, and if that is the case, what is the need for hybrids? A standard unit can not run much more than standard boost EFFICIENTLEY. Tuning cars is more than just how much boost you can run. You need to take into consideration things like heat as well. A standard turbo will get extremely hot at 26psi, thus counteracting the compressing effect and therefore reducing power and creating dangerous knock as the intercooler struggles to cool the charge air back down. You also encounter the problem of overspeed, due to the turbine side being too small. This will cause premature wear on the bearings, hence the need for a larger turbine side.

And alittle more:


The T28 would be more responsive, has a substantially larger compressor wheel. In fact, to get technical, the diameter of a Td04hl wheel is 56mm with a 43.4mm inducer, whereas the T28 wheel is 60mm diameter and has a 46.4mm inducer. Therefore the T28 is 14% larger which would roughly equate to a 40bhp higher maximum working range. A 15G is capable of not much more than standard power, efficiently. The Mitsubishi compressor design is very old with a full blade design, which gives a very narrow operating range, and a common side-effect is the inducer chokes up. The T28 uses a new half blade design.


Our hybrid also comes with a substantially larger turbine side, designed by us for the Volvo, not a standard T28 housing. Yes, it does require a fitting kit, but this is supplied. Yes, it does away with the dump valve, but this is not a necessity. Dump Valves are only needed on the standard Mitsubishi turbos due to there compressor design. The narrow operating range can cause surge, and a dump valve is used to help counter-act this problem. If the user would like a dump valve, it can be plumbed in elsewhere very easily.

There ya go new I could find it.....Hope that answers your questions.

Regards

Iain