Quote:
Originally Posted by robnitro
Why not push the compressed air into the intake instead? For the work done to get X flow/psi of that air into intake it takes more on the exhaust side to get the same intake charge as the exhaust side has losses through the turbo. The extra air on intake with fuel burning will create much more volume/flow than the air alone on the exhaust side too.
I think it's more for emissions in their case.
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It is specifically used in both cases above as a legitimate way to reduce turbo lag (although enough to be beneficial is debatable). koenigsegg is injecting 290psi for example. The guys taking their 335d's to the drag strip and trying to get the best times possible couldnt hurt to at least research a little further into this.
I mentioned the reasoning for why exhaust manifold and not the intake due to venting to atmosphere if you dont have something like the asv (auto shutoff valve) temporarily cut-off the filter housing to create one path so most air injected doesnt just go to atmosphere. But no need to make it so complex hardware & coding wise as it would actually work better in the exhaust manifold (even better in the turbine housing on single turbo setup as shown in patent above) anyway because it would be hitting the blades that were designed to spin the compressor most effectively causing the fastest spool up.
The point is to reduce turbo lag not necessarily force more air into the engine because it is already getting what it wants unless the intake is inadequately spec'd. Colder air (more dense) hitting the turbine side will actually make it spin faster than any exhaust gas as well, just figuring out the injection pressure would be the task and hoping it doesn't trigger a lean false positive limp mode.