Bored at work today and I got to thinking. Has anyone tried piping in an electric high-pressure air compressor to the exhaust side of a turbo? Essential I was thinking you could jet an additional stream of compressed air (100psi or so) in addition to the exhaust flow to help spin-up the turbo at off-idle. Could virtually eliminate turbo lag.

Let me know, why wouldn't this work? Or why hasn't anyone done this yet, or if so why haven't I heard of it???

 

The idea is similar to an electric supercharger and because of that it has its downsides.

1. An air compressor takes a good amount of energy to run (especially to run at the level to spool a turbo faster then the exhaust gases would).

2. An air compressor is also relitivly large so shoving into an already space limited car would be a project of its own.

3. To reduce the already minimum amount of lag that the turbos have now on our car, its probably not worth it


Just my guess on the idea

 

that 100psi of air you are talking about is over about a 1-3mm opening usually. Trying to spread that same amount of air over 60-63mm will not even be able to fill the vacuum of the engine.

 

I always wondered about something kinda like this..

Suppose instead of a BOV, the excess air was stored in a pressurized tank. Next time you get on the gas and the turbo isn't spooled, the tank releases the air. Would it work? Is it feasible?

 

You would have to pressurize the excess air to get it into the pressurized tank. So you would need an air compressor to do that. Also as kane said, an air compressor only makes its high PSI through a very small hole, not at 60ish mm.

Also air compressors are by no means instant either, they take a GOOD bit of time to built up pressure. So in the short amount of time that the turbo is "laging" you would have to built up the pressure and release it. Not happening sorry to say.

 

Since this is your great idea why don't you spend your money and do it

 

I wasn't referring to using an electric compressor.. I was referring to taking the excess compressed air (boost) that's normally vented to the atmosphere via a blow off valve. I just don't know enough to say whether or not that would make adequate stored energy to spool a turbo.

Didn't Prodrive have some prototype car that burned fuel in the exhaust manifold to spool the turbo when off-boost?

 

The charge air is only at 5-20psi. You'd be better off plumbing a straw to the cockpit so you could blow in it.

As for anti-lag systems, yes Prodrive use this on rally cars. And it's also an option on the AEM EMS. Elaug uses it on his S2000 via the Motec EMS.

 

Every good stand alone has a anti-lag function. Even the AEM EMS has it. It's really hard on the turbo and an average rally car changes the turbo after each race due to the anti-lag function. You retard ignition but let the injectors inject fuel. Unburned fuel exits trought the hot manifold, ignites and creates a vacuum behind the turbine wheel thus making it's spin and "maintain" boost during shifts.

BTW. since when is lag an issue on a properly sized BB turbo?

 

Maybe it isn't an issue, what is the usual rpm that your turbo has been spooling up to full pressure?

Also i wasn't thinking of trying to pressurize the entire 60mm. If you have ever cleaned off a computer fan with a compressed can of air, think of a thin high-pressure jet of air pushing on the blades. You don't HAVE to cover the whole blade, the pressure should be enough to push the blade, there-by starting the spool up.

And the reason I haven't tried it yet is because I don't have a turbo yet. Just had a curious thought during some idle time at work.