Twin Charging.....super and turbo....the 'Superbocharged'

mrbeige wrote:So, for example, take a 2.0l 16v engine, strap an Eaton M62 and say a GT28 to it. how would you go about routing the charge? Into the Eaton first then on to the Turbo would be the most logical, but once the turbo spools up, will the super be able to deliver enough air, or will it start to choke the turbo? What I mean is, would you want to bypass the Eaton once you've spooled?

Turbo compressors are very delicate, so if if you do it that way I reckon you'll end up bending them? Directing the S/C's boost over the turbine wheel might work though and I'm sure it could be done using existing EGR (Exhaust Gas Recirc) technology? Would need a redesigned turbine housing though, or a dedicated port on the manifold very close to the turbine wheel and it would have to be post lambda too.....hmmmm, tricky!

The way JD Engineering did their's makes sense in theory.

Take a 20VT engine with a turbo and a G60. The turbo's compressor output feeds the G60's inlet and the combined boost is then intercooled before entering the intake.

When the turbo is out of it's boost zone, the G60 helps turbo spool by effectively pulling air through the compressor. When the turbo comes on boost, the G60 is compressing the already compressed air still further, so in theory it's an easy thing to do. In practice Mr Dik used 3 ECUs!! A G60 Ecu, 20VT ECU plus another one, can't remember what that one was for. Bonkers!

I'm sure it could be done a little easier than that, but his way works very well by all accounts.

3 things concern me with that method though:-

1) Intake charge temp. 70-80 deg C (depending on boost) out of the turbo into G60 Plus the G60's own heat = very hot indeed. You would need a very good intercooler that's top of league division 1, plus some supplementary cooling I would imagine, such as meth injection or petrol spray onto the G60's scroll.

2) Turbo lifespan. Turbos are designed to produce boost relative to exhaust pressure and volume, so I'm not sure how well it would take to being forced to make boost outside of it's comfort zone by being 'sucked on' by an S/C. I'm also not sure how much of a restriction shoving boost into a supercharger would present to the turbo. Boost surging is a bad enough problem as it is, without shoving an S/C into the mix to complicate matters It would work though, but for how long is anyone's guess. Careful matching of turbo and S/C flow rates is essential tho.

3) If the turbo throws a blade or if the turbo sucks in something harder than ally, you'll lose both the turbo AND the S/C, but I doubt anyone mad enough to build a Superbocharged engine would worry about that!

Well if used a great big feck off GT30Which im sure is way oversized compared to the grenade. He also used the 3 throttle bodies did he not.

Dunno, didn't read the whole article but additional throttles would indeed be needed to avoid excess boost and noise at low rpms.

The GT30 is far from feck off big, it's actually a tiddler relatively speaking

Frame size wise its the same as your small 35 is it not. Relatively speaking its huge with relation to airflow compared to the grenade as you said flow rates would need to be matched, well put 2 grenades on then. Suppose he can put strain on his stuff though as he owns 1 of the best tuning outfits in europe.

Surely you'd be better having two separate feeds into the intake, rather than compond charging it? As Kev says, you wouldn't want to take out both chargers in the event of a failure.

So if you were to have two separate feeds into one inlet, how would you go about switching between the two, or could you use some sort of one-way valve?

junkie wrote:Frame size wise its the same as your small 35 is it not.

Same CHRA size but very different wheel sizes and Compressor AR.

interesting link of a toyota supercharger clutch system
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Well, after discussing using an Eaton on a VR and I now understand why they fit a clutch to the charger. As a roots type charger is positive displacement, it requires a means to limit the boost at idle. As mentioned elsewhere the guy on VR6OC who has fitted an Eaton, had to throttle the intake to the charger, as teh idle boost caused al sorts of issues. Using the clutch has the same effect here I guess. Elegant solution.

mrbeige wrote:Well, after discussing using an Eaton on a VR and I now understand why they fit a clutch to the charger. As a roots type charger is positive displacement, it requires a means to limit the boost at idle. As mentioned elsewhere the guy on VR6OC who has fitted an Eaton, had to throttle the intake to the charger, as teh idle boost caused al sorts of issues. Using the clutch has the same effect here I guess. Elegant solution.

Interesting...
Going to look into this some more.

YOUR NUTS!

ctwg60 wrote:YOUR NUTS!

just idle ODDUNIT chat.
No harm.

An example of an AC unit clutch.
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You know what though....I love that idea. A clutched Eaton M92 on a VR. You could use the clutch mechanism from an AC compressor above. I wonder if it just like a switch, or you could provide the field coil above with a PWM type signal to allow it to slip....

mrbeige wrote:You know what though....I love that idea. A clutched Eaton M92 on a VR.

mrbeige wrote:
You could use the clutch mechanism from an AC compressor above.

I wonder if it just like a switch, or you could provide the field coil above with a PWM type signal to allow it to slip....

dunno but i bet it wouldn't be that hard ..

Big advantage of the clutch I would of thought is that you don't need to over-rev the charger when the turbo kicks in.

ctwg60 wrote:Big advantage of the clutch I would of thought is that you don't need to over-rev the charger when the turbo kicks in.

exactly.
62mm pulley time

You better make sure the clutch is working!

I don't think it would work. You need to see Tom's Eaton'd VR to see what you're letting yourself in for!

Aye, you're probably right, but wouldn't it be fun trying

kevhaywire wrote:I don't think it would work. You need to see Tom's Eaton'd VR to see what you're letting yourself in for!

where can I snoop that then?

are the ac compressors in VR's clutched?