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350bhp filth
- Thread starter R20 CWH
- Start date
Dude it's direct injection. They are capable of a lot of flow because of how quick they have to deliver during fuel-stratified (fuel saving) operation.
It's fitted with an APR direct injection high pressure pump with a bigger piston to push more fuel into the rail and maintain the 120 bar operating pressure.
I'm a wondering if it's 350bhp as i didn't think the turbo was up to that. iirc it's just a K04.
It may have an uprated fuel pump pushing fuel into the rail, but the actual injector heads would need to be increased. FSI injectors are absolutley no bigger than they have to be because of the fuel saving and that is how FSI works. no extra capacity at all.
I'm sorry mate, but I'm pretty sure your wrong. During stratified operation those injectors have to deliver all the fuel that the clylinder requires in about 10 degrees of crank rotation. That requires a fair old bit of flow capacity. So when you start operating homogenously for full power (lol, homo) then you've suddenly got <180 degrees to get all the fuel in. Easy peasy, no problem.
In fact FSI injector heads are normally smaller to increase the pressure of the squirt. Stratisification happens when the pressure is so high the fuel pulse is momentarily compressed while it enters the piston chamber. When the pistons moves down and creates a vacumn the compressed fuel pulse then has a higher expansion ratio allowing more oxygen to be mixed with a smaller amount of fuel.
Don't mix up pressure and flow rates, they are 2 different things entirely
Don't mix up pressure and flow rates, they are 2 different things entirely
The holes on the injectors are smaller because the pressure behind them is 120bar rather than 3-5bar!
What your describing doesent sound anything like direct injection.
What is this about the piston moving down? Is that meant to be the power stroke or the induction stroke? I don't know where your getting this, but i'd say your either describing it all wrong or you havent a clue.
The objective with fuel-stratified operation is to get an area of slightly rich or stoichiometric mixture right under the spark plug, surrounded by fresh air at the time of the spark. That requires last mili-second injection. Theres no 'piston moves down' about it.
What your describing doesent sound anything like direct injection.
What is this about the piston moving down? Is that meant to be the power stroke or the induction stroke? I don't know where your getting this, but i'd say your either describing it all wrong or you havent a clue.
The objective with fuel-stratified operation is to get an area of slightly rich or stoichiometric mixture right under the spark plug, surrounded by fresh air at the time of the spark. That requires last mili-second injection. Theres no 'piston moves down' about it.
I am talking about the induction stroke and a negative pressure allowing a much higher fuel to air ratio because of the higher expansion ratio caused by an exteremely high pressure compressed pulse of fuel. this allows a mixture that requires less fuel but does the same thing. timing has got bugger all to do with it.
You've mixed up the two operating modes of GDI.
You've got a homogenous mode. That is for the higher power end of the map.This injects on the induction stroke and aims to get a stoichiometric AFR in the cylinder. The advantage of GDI here is that the fuel cools the compressing mixture and allows higher compression ratio.
Then the stratified mode, for fuel ecomony. This injects just before the piston comes to TDC on the compression stroke. The AVERAGE cylinder mixture is allowed to be lean. But that's only because there are 2 separate zones of mixture in the cylinder. The stochiometric around the spark plug and the clean air in the rest of the cylinder. The advantage is the surrounding air insulates the combustion from the cylinder wall and increases thermal efficiency. This with the extra compression ratio increases engine efficiency further.
If your going to talk about fuel compression, that's more an issue of diesel direct injection tbh. You can't 'allow' a significantly leaner mixture in the whole cylinder, that would cause really slow combustion or a missfire.
You've got a homogenous mode. That is for the higher power end of the map.This injects on the induction stroke and aims to get a stoichiometric AFR in the cylinder. The advantage of GDI here is that the fuel cools the compressing mixture and allows higher compression ratio.
Then the stratified mode, for fuel ecomony. This injects just before the piston comes to TDC on the compression stroke. The AVERAGE cylinder mixture is allowed to be lean. But that's only because there are 2 separate zones of mixture in the cylinder. The stochiometric around the spark plug and the clean air in the rest of the cylinder. The advantage is the surrounding air insulates the combustion from the cylinder wall and increases thermal efficiency. This with the extra compression ratio increases engine efficiency further.
If your going to talk about fuel compression, that's more an issue of diesel direct injection tbh. You can't 'allow' a significantly leaner mixture in the whole cylinder, that would cause really slow combustion or a missfire.
