superchargers

Yugguy said:
We had this thread a while back, do a search.
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If we considered every turbocharger to be a supercharger (which it is - the full name is turbo-supercharger) then all turbo-diesel cars are supercharged.

I am not aware of any current road cars which utilise mechanically driven superchargers in conjunction with a diesel engine.

Mechaninal supercharging is used to great effect in large two-stroke diesels. It's almost essential to be honest in these installations. There is very little scavenging in any diesel engine because there is no throttle.

So the intake has to be pressurised from right startup, regardless of revs simply to charge the cylinder effectively.

By large I'm thinking of nautical and railway applications.

Look up Napier Deltic.
 
can you fit a supercharger to a turbo charged engine? The way i see it is that the supercharger boosts in constant relation with the rpm's, and if that charged air runs through the turbo it'll increase the rpm, in-turn increasing the boost from the turbo, increasing the rpm's again which is charging the supercharger even more... correct me if in wrong
 
It has been done by VW with the brilliant TFSi 1368cc unit. But it's not as simple as simply bolting on a supercharger. Get the boost ratios wrong and you'll simply find the turbo trying to suck the blades off the supercharger

Diesels are ideal for turbocharging because the engines don't have throttles.
 
Yes they are indeed.
But something I've only seen done once on a diesel is a supercharger and a turbocharger.
Best way to do it is having the turbo blowing into the supercharger, then the supercharger blowing though an intercooler of some sort then up to the intake manifold.
I've seen this setup on petrols a few times and who knows...I might consider doing it myself ;)
 
you couldn't have the turbo charging the supercharger because the supercharger would act as a regulator. The " benefit " boost from the turbo would be held back from reaching the engine because the supercharger is still running in ratio with the engine and hasn't picked up because the rpm's haven't picked up whiich makes the supercharger boost.

in essence the turbo isn't "allowed" to do its job because the supercharger runs off the engine rpm not off the boost that enters it which leaves the turbo creating boost but the engine not getting to use it.

how does the twin turbo 2.7 v6 peugeot engines run, one small turbo charging a larger one or is it one turbo for 3 cylinders and another for the other three? i always thought that if one small turbo charging a bigger one would create a huge amount of vaccume in the inlet side of the smaller turbo, would this not be detrimental?
 
The V6 HDi uses two identical turbos, one for each bank of 3. These are tightly regulated by the ECU to ensure that exactly the same boost is applied to both cylinder banks.

petescustompipes said:
you couldn't have the turbo charging the supercharger because the supercharger would act as a regulator. The " benefit " boost from the turbo would be held back from reaching the engine because the supercharger is still running in ratio with the engine and hasn't picked up because the rpm's haven't picked up whiich makes the supercharger boost.

in essence the turbo isn't "allowed" to do its job because the supercharger runs off the engine rpm not off the boost that enters it which leaves the turbo creating boost but the engine not getting to use it.

how does the twin turbo 2.7 v6 peugeot engines run, one small turbo charging a larger one or is it one turbo for 3 cylinders and another for the other three? i always thought that if one small turbo charging a bigger one would create a huge amount of vaccume in the inlet side of the smaller turbo, would this not be detrimental?
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how does the small turbo charging the big turbo situation work? would it not be terribly sore on the small turbo or am i thinking of this wrong?. i know the tractor pulling men use up to four turbos in a line and a diesel engine is a diesel engine whether its in a tractor producing 4000bhp or a car producing 200bhp...
 
The smaller turbos are bypassed as the larger ones get into their stride basically. At least for road car purposes I think this is the most obvious way of doing it.

The 4000lbft racing machinery is possibly different.
 
Most likely will be,

I've been thinking about ways in which to twin turbo my car using a smaller turbo and a bigger one.
Leave the standard turbo in and weld up the wastegate and remove the wastegate actuator then use an external wastegate in the exhaust manifold in place ofthe EGR valve.
When the external wastegate sences it's boost limit then it opens then diverts the excess exhaust gasses to the other side of the small turbo (after it) which will be feeding the bigger turbo..

something along those lines I reckon...
 
The principle is sound but I reckon it'll need considerable development and refinement to achieve what you're looking for. I think it's unlikely to work without considerable electronic intervention.
 
Boost controllers maybe?
Really I would want as little electronic intervention as possible
Maybe a couple of MBC's should do the trick
After all I am looking for big power but without the horrific turbo lag
 
petescustompipes said:
can you fit a supercharger to a turbo charged engine? The way i see it is that the supercharger boosts in constant relation with the rpm's, and if that charged air runs through the turbo it'll increase the rpm, in-turn increasing the boost from the turbo, increasing the rpm's again which is charging the supercharger even more... correct me if in wrong
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wrong, you need to run the boost from the turbo through the supercharger, watch this space

http://www.torquecars.com/forums/f41/picks-my-engine-bay-9158/index3.html
 
please explain how it works, because it works (supercharger then turbo) in my head fine but in reality it doesn't... iv been studding this for hours and its all wrong, but why???
 
I'm not going to try and explain it because there is not one simple solution. Using a pair of turbos, regardless of the configuration requires extremely careful design.

Using a mechanical supercharger together with a turbo(super)charger is even more radical. VW has managed this to great effect in the 1.4 TFSi engine but I suspect that the development costs were pretty high and that the oeprating principles are pretty complex. It's not the first of its kind but it's probably the first to hit truly mass market cars.

There is no simple one-size-fits-all configuration.

I steer away from mods to be honest, apart from a decent custom ECU remap I have never modified any cars. Which is not to say that it shouldn't be done, but I can think of easier and cheaper ways to ramp up usable performance, such as buying a different car in the first place.
 
compound charging will only really work if you have a roots type of supercharger,(which is a compressor) a centrifugal turbo/supercharger is really only an air mover. if the supercharger boosts 7psi, then if you have 12psi going into it from the turbo you will have 19psi coming out (but in practice it will be more like 22psi)
 
HDi fun said:
but I can think of easier and cheaper ways to ramp up usable performance, such as buying a different car in the first place.
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Find me a car that has over 350bhp for less than a grand, and I'll bye it. (then I'll start to mod that.......lol)
I find half the fun is doing things my own way.
 
You can't just add absolute or relative boost pressures. Flow rate is more significant. Roots blowers are positive displacement devices. Other types aren't.

At the end of the day airflow is measured by mass divided into time, irrespective of pressures at any point in the intake system.
 
So true,

I've been trying to explain this to people for years, (and i'm only 21) just because someone is running more boost on the same engine doesn't mean more power,
For example, if you had say a Garrett GT1549 running 20 psi boost, and a Garrett GT2560 running 15 psi, which turbo is likey to be flowing more air and thus is more likely to make more power on the same engine?

and Claymore what supercharger is that you have? an Eaton E90?
 
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