lag-less boost anyone?

[gareth]

how about installing a small jet engine as well as your 'normal' engine to provide constant lag-less boost!

[N00b]

RS200E engine anyone?
0-60 in 1.8 seconds.
0-130 in just over 6 seconds.
Standing 1/4 mile in sub 9.5 @150mph+


Does anyone know if you can hook one of these upto an iS box?

[GeoffBob]

how about installing a small jet engine as well as your 'normal' engine to provide constant lag-less boost!

Haven't seen the video yet Gareth (not enough bandwidth here at home), but FYI, the clever formula-1 engineers of the mid '80's pioneered what they loosely termed the "5-stroke engine" to counter turbo lag. Basically, the engine management was programmed to dump extra fuel into the engine while braking and cornering. Simultaneously the ignition was retarded or cut, allowing pretty much unburned fuel to be dumped into the exhaust. With the heat of the turbine wheel this would ignite in the turbo and very effectively keep the turbine spooled up, even though the engine rpm were low. The system was characterised by black smoke coming out the tail pipe.

This principle is not that different to a jet turbine. In fact a very nice turbine engine can be made from an old turbo, some bits of tubing and an injector to pump fuel (paraffin works well) into the turbine. Of course some method of ignition is required to get the thing started, and compressed air to initially spool up the turbine, but once it gets going its self sustaining. If the experiment gets out of hand it can do a lot of damage (you need to have a remote fuel-cut close at hand).

[gareth]

that sounds rather interesting
a similar principle to rally car anti-lag systems i guess?

[GeoffBob]

Just watched that video Gareth, very interesting. Sounds pretty much like I described above, except that he is using proper gas turbine from a helicopter to do the job. See how he uses compressed air from a tank to spool the tubine up in the begining. Once he fuels and ignites it, the turbine is self sustaining, unlike a turbocharger which spools down everytime you take your foot off the throttle. It's a vey clever and unique idea by the looks of it, but would cost you a fortune in parafin if you had to keep that turbine idling while stuck in traffic perefect for what he's doing though. Brilliant idea!

[ross_jsy]

how about installing a small jet engine as well as your 'normal' engine to provide constant lag-less boost!

Haven't seen the video yet Gareth (not enough bandwidth here at home), but FYI, the clever formula-1 engineers of the mid '80's pioneered what they loosely termed the "5-stroke engine" to counter turbo lag. Basically, the engine management was programmed to dump extra fuel into the engine while braking and cornering. Simultaneously the ignition was retarded or cut, allowing pretty much unburned fuel to be dumped into the exhaust. With the heat of the turbine wheel this would ignite in the turbo and very effectively keep the turbine spooled up, even though the engine rpm were low. The system was characterised by black smoke coming out the tail pipe.

This principle is not that different to a jet turbine. In fact a very nice turbine engine can be made from an old turbo, some bits of tubing and an injector to pump fuel (paraffin works well) into the turbine. Of course some method of ignition is required to get the thing started, and compressed air to initially spool up the turbine, but once it gets going its self sustaining. If the experiment gets out of hand it can do a lot of damage (you need to have a remote fuel-cut close at hand).

Isn't that just the fundamentals of antilag though Geoff?

[GeoffBob]

Isn't that just the fundamentals of antilag though Geoff?

Yip. And that's what the chap in the video is doing, except using a turbine engine, which is self sustaining, to spool his turbocharger, rather than his exhaust gasses.

it might not be immediately obvious, but there is little difference between a turbine engine and a turbocharger. Both use the kinetic energy of an expanding gas to spin a turbine, and both do work via an output shaft. The point I wanted to make, however, is that implementing the popular antilag strategy (burning fuel in the turbine) is not that different to what this chap has done with his helicopter turbine engine. The turbine engine is, however, at all times self propelling and in no way dependant upon engine exhaust output, so he keeps his turbo spooled up all the time. Nifty! Very clever of him I must say.

[ross_jsy]

Ah right, can't watch the vid due to being at work.

But surely at say idle there will be an excess of gas? Or does it use some kind of vent dependant on throttle position?

[GeoffBob]

Ah right, can't watch the vid due to being at work.
But surely at say idle there will be an excess of gas? Or does it use some kind of vent dependant on throttle position?

I doubt it, he probably has a wastegate on the turbo that works off the engine throttle (if only to keep it simple). As I understand it he uses the exhaust gas from the gas turbine engine to spool up the turbine of a conventional turbo, whose compressor in turn boosts his relatively small 1700cc engine. In other words, the turbine engine effectively boosts his petrol engine.

If he wanted to avoid the situation where the turbo was spooled up to excessive speeds (thus having to blow off air from the turbocharger compressor) he would surely just bypass the turbocharger turbine with a wastegate, thus blowing off the exhaust from the turbine engine.

This is the only pic of the car I could find here:



You can see someone on the right pumping compressed air into the turbine engine to spool it up. The only downside that I can see is that the turbine engine has to run for the turbocharger to boost, and so the turbine engine runs near full rpm before he sets off. But then its not as if he takes the car shopping, so its perfect for what he does with it. The power to mass ratio must be phenomenal!

[gareth]

I thought you'd like that GeoffBob

that is lateral thinking at it's best

[ross_jsy]

I am with you now.

But instead of using the exhaust gases from the turbine I am wondering if it would be possible to have a mechanicaly driven compressor driven off the turbine?

[GeoffBob]

I am with you now.

But instead of using the exhaust gases from the turbine I am wondering if it would be possible to have a mechanicaly driven compressor driven off the turbine?

From a theoretical standpoint, yes, I really don't see why not. The turbine engine drives the helicopter rotors via a gearbox, so why not do the same on a FI engine - effectively a turbine engine driven supercharger.

This idea would however face two practical problems. 1) How to gear the turbine engine to the compressor so as to run the compressor at the correct speed, and 2) how to regulate the speed of the compressor while 'off boost' (no wastegate on a supercharger), so some sort of clutch would be required.

So long as the practical problems can be overcome I think it's an idea that would work.

[HairyScreech]

its known as hypobaric turbo charging, did quite a bit on it for a project a couple of years ago.