2.0 FSI Service intervals

[DBCPerformance]

http://www.vw.com/spweb/pages/spweb/serv_maint_results_full.jsp?Model=GTI%20FSI&year=2006&engine=2.0FSI&odometer=10000&units=MILES

[L-Dub]

Noob question:

It says 2.0FSI. Does this apply to the turbo'd version? Thanks.

[DBCPerformance]

yes it does 2.0FSI is the 2.0T

[kirk180]

Let me take a stab at explaining this L-Dub. But I'll remind you that I don't work on auto engines. So I'll put it in the only terms I know.

It does not stand for the "turbo" it stands for the way the fuel is injected into the cylinder/ Kind of like the old "FI" meant Fuel Injected. The "FSI" means Fuel Stratified Injection. It's a more modern way to inject the fuel into the cylinder that works under a higher compression ratio and helps to minimize premature combustion while giving you more power via a "bigger bang". The common fuel injector operates at about 45 psi while this one requires about 1600 psi. Instead of throwing the fuel into the cylinder at the same time as the air and compressing the two hence making your combustion (which gives you your power) the FSI only puts the air in there first enabling it to get a higher compression because the fuel isn't in there to create a premature combustion. Then once the cylinder has compressed the air and met its "firing point" the fuel is then timed to squirt into each cylinder independantly via its FSI mechanism to create the greatest most evenly distributed explosion. However, I believe the FSI's main intention was to save fuel under light to moderate work loads. So actually, it does all sorts of good things for the engine.
If someone feels I am wrong then please chime in and I will re-research my answer. But I've done it before and this is about the best I can explain it. Air and fuel use to and still are dispensed into many automobile cylinders before it starts it's compression stroke and then once it reaches its threshold the air/fuel mixture will combust. Well the GTI did away with that technology to give you a more fuel efficient, power increasing way to utilize your fuel.

[kirk180]

yes it does 2.0FSI is the 2.0T
Maybe I misunderstood his question. There I go always reading too deep into questions. Oh well, either way it's cool. I guess the few who end up reading this may actually learn something about the way their Fuel Stratified Injection system works. :w00t:

[DBCPerformance]

:laugh:

[bigdyno]

I think another advantage to the high pressure injection is finer atomization that allows a more homogeneous mixture of the fuel and air. This will produce better burn patterns and in theory a higher percentage of the potential energy will be realized.

With all the little things they are doing these days to squeeze every little drop of power from the engines I wouldn't be surprised if you see other car builders developing similar systems. Honda had done research on direct injection two strokes a few years back, I don't think they were high pressure systems.

However, there seems to be more and more technology being developed in this direction. Bombardier has been using the Orbital direct injection technology in Sea-Doos for a few years now (http://www.orbeng.com.au/orbital/aboutOrbital/aboutOrbital.htm) and has been doing well with it

[kirk180]

Oh yeah ScuderiaVw2?:slice:

[kirk180]

I think another advantage to the high pressure injection is finer atomization that allows a more homogeneous mixture of the fuel and air. This will produce better burn patterns and in theory a higher percentage of the potential energy will be realized.
Yeah, I just said that (only in different words):bonk:

Good point though. Car mfgr's probably will all start to make FSI systems or something similar to it. I'm sure it won't stop there. Technology just keeps getting more and more amazing.

[alf]

nice find berk!

in doh doh mexican term the gas is shocked before entering the cylinder. or "stratisfied".

[L-Dub]

yes it does 2.0FSI is the 2.0T

Thank you!

Maybe I misunderstood his question. There I go always reading too deep into questions. Oh well, either way it's cool. I guess the few who end up reading this may actually learn something about the way their Fuel Stratified Injection system works. :w00t:

No problem, I certainly learned something new about my new car, and that is always welcome :headbang:

[bigdyno]

Hey Kirk,
just to let you know, there is no difference in compression between the two types of fuel injection. If you had higher compression (past a certain point), you would get premature combustion. The problem with regular FI and also taking a step back to carburation, you don't get a complete burn all the time and this is why we have CATs.

The FI is more efficient at mixing the F/A mixture than carbs the same way the new high pressure system is an improvement over regular FI. Again this is to squeeze more efficient power out of the same ammount of gas.

For gas engines to have the combustion started by high compression, we are talking upwards of 14:1, there would have to be some seriously tight clearances in the combustion chamber. Diesel engines, however, run exactly like this, they are typically around 22-24:1 to be able to start the reaction.

I would be happy to discuss this further if you have any questions:thumbup:

[slickvic]

Hey Kirk,
just to let you know, there is no difference in compression between the two types of fuel injection. If you had higher compression (past a certain point), you would get premature combustion. The problem with regular FI and also taking a step back to carburation, you don't get a complete burn all the time and this is why we have CATs.

The FI is more efficient at mixing the F/A mixture than carbs the same way the new high pressure system is an improvement over regular FI. Again this is to squeeze more efficient power out of the same ammount of gas.

For gas engines to have the combustion started by high compression, we are talking upwards of 14:1, there would have to be some seriously tight clearances in the combustion chamber. Diesel engines, however, run exactly like this, they are typically around 22-24:1 to be able to start the reaction.

I would be happy to discuss this further if you have any questions:thumbup:

I disagree. Most turbo charged cars have a lower compression (8:1) than normal aspriated engines (9.5:1) because the heated intake temperature could cause pre detonation. The FSI engine is able to use a higher compression ratio (10.3:1) because the fuel is directly injected into the cylinder at the precise moment before spark ignition under high pressure.

DISCLAIMER: The first 2 compression ratios listed are an approximation and vary among manufacturers.

[kirk180]

I disagree. Most turbo charged cars have a lower compression (8:1) than normal aspriated engines (9.5:1) because the heated intake temperature could cause pre detonation. The FSI engine is able to use a higher compression ratio (10.3:1) because the fuel is directly injected into the cylinder at the precise moment before spark ignition under high pressure.

DISCLAIMER: The first 2 compression ratios listed are an approximation and vary among manufacturers.
Correct. You can reach a higher compression ratio without the fear of premature detonation due to the fact that the fuel isn't in the chamber being mixed with the air yet. Hence the reason this FI system requires about 1600psi in order to overcome the greater "compression" in comparison to one that injects the fuel in before compression that only requires about 45psi. That's a huge difference in requirements for a fuel injection system. But it was worth it. Now that they can go to a higher compression ratio safely and follow that with a higher pressured burst of fuel thus creating a larger or as stated before "bigger bang". They can then in turn give you more power.

My offer extends back to you and your comments are also welcome. But perhaps this has cleared any misunderstandings of my previous post. Sorry to take so long bigdyno. But I never knew your comment was posted until I saw it today.:thumbsup:

[bigdyno]

I disagree. Most turbo charged cars have a lower compression (8:1) than normal aspriated engines (9.5:1) because the heated intake temperature could cause pre detonation. The FSI engine is able to use a higher compression ratio (10.3:1) because the fuel is directly injected into the cylinder at the precise moment before spark ignition under high pressure.

.

I'm not sure what you are disagreeing to, I wasn't stating a CR for our cars specifically. Higher compression in general leads to the need for higher octane fuel. Our cars run a lower compression ration because the air comming is is pressurized, so the actual CR is a multiplier of the cylinder CR. (eg: 8.5 cylinder CR x 10 Lbs boost= 11:1 this is an example only, the math may be totally wrong, just trying to explain the theory)

I am also not sure that the intake temperature being higher due to boosting would be the sole cause of detonation. I am sure it would play a part, but the biggest reason for lower CR is the boost. If you run 15 lbs boost in a regular CR engine (let's say 9.5:1) you would have too much compression and probably have blowby problems until you blew a head (gasket, studs, or worse) It would also put excessive stress on pistons, pins, rods and crank. All bad parts to have breaking on you.

[kirk180]

^^^So then you agree on the higher compression being able to be achieved due to FSI that I was explaining though?

[bigdyno]

Hence the reason this FI system requires about 1600psi in order to overcome the greater "compression" in comparison to one that injects the fuel in before compression that only requires about 45psi. That's a huge difference in requirements for a fuel injection system. But it was worth it. Now that they can go to a higher compression ratio safely and follow that with a higher pressured burst of fuel thus creating a larger or as stated before "bigger bang". They can then in turn give you more power.

:
Good point about the pressure being needed to overcome compression, I am sure this is a factor in the psi of the injectors. I still think that part of the reason for the higher pressure is to better mix the fuel/air, allowing better (more consistant) mixture that will allow more power to be harvested from said mixture.

Keep in mind that the one steady factor in this equation is the speed at which fuel burns. Because of this, the fuel has to be injected soon enough before TDC to allow a full burn. Because you are adding more fuel to a boosted charge, you need more burn time, I would think that the computer takes this into account as well as timing. Considering the time it would take for this fuel to burn, it would make sense that the fuel is injected while there is still considerable compression stroke left ( talking in degrees BTDC) for some heat to be generated by "rubbing" the fuel and air atoms together. Sorry, can't think of a better word for it.

Typically, the temperature of the intake charge is of concern only for the reason that higer temperature air is less dense, ergo less potential power generating ability. I have never heard of any reference to the concern of predetination from a hot intake charge.

[bigdyno]

^^^So then you agree on the higher compression being able to be achieved due to FSI that I was explaining though?

Yes. It would make sense that this is a factor, however, you still need to look at what your total CR is (cylinder CR x boost pressure, not sure of the actual equation).

Performance engines have been bumping CR due to new technology and better materials/maufacturing methods, I am sure this has a great deal to do with the CR in our engine. I haven't seen any of the engine numbers yet (CR, bore, stroke, cam timing etc) so I can't comment specifically on where our engine sits.

I wouldn't be surprised if this engine has higher cylinder CR than the 1.8T, again from newer materials, methods and technology.

[slickvic]

I stand by my earlier comment that a typical turbocharged engine has a lower compression ration that a non aspirated engine. Also the VW FSI turbo engine has a higher than normal compression ration due to the direct injection.
My Wife's 2005 Legacy GT 2.5 turbo engine has a compression ratio of 8.2:1
While my GTI has a compression ratio of 10.3:1.
This is before the turbo does anything so no "voodoo math" is involved.

[slickvic]

I am also not sure that the intake temperature being higher due to boosting would be the sole cause of detonation. I am sure it would play a part, but the biggest reason for lower CR is the boost. If you run 15 lbs boost in a regular CR engine (let's say 9.5:1) you would have too much compression and probably have blowby problems until you blew a head (gasket, studs, or worse) It would also put excessive stress on pistons, pins, rods and crank. All bad parts to have breaking on you.

Not exactly. A diesel engine has a compression ratio close to 20:1
The increased pressure ignites the fuel because the compressed air is that hot.
You cannot have that high of a CR with a gasoline engine because the fuel would preignite due to th higher cylinder temp, not because a stronger engine could not be built. :wink:

[bigdyno]

I stand by my earlier comment that a typical turbocharged engine has a lower compression ration that a non aspirated engine. Also the VW FSI turbo engine has a higher than normal compression ration due to the direct injection.
My Wife's 2005 Legacy GT 2.5 turbo engine has a compression ratio of 8.2:1
While my GTI has a compression ratio of 10.3:1.
This is before the turbo does anything so no "voodoo math" is involved.

I agree that a turbo engine has a lower CR than a non-boosted car. You have to remember that a Legacy isn't as performance oriented car as our GTI, hence the lower CR.

The difference may also (but not necessicarily in this case) be because the turbo is producing more boost in a lower CR engine. This could produce the same end charge pressure.

[bigdyno]

Not exactly. A diesel engine has a compression ratio close to 20:1
The increased pressure ignites the fuel because the compressed air is that hot.
You cannot have that high of a CR with a gasoline engine because the fuel would preignite due to th higher cylinder temp, not because a stronger engine could not be built. :wink:

I think the pre-ignition would be caused by the friction between the air and fuel molecules at these levels. When stating that you would break engine parts in a gas engine at higher CR, I am referring to boosting an engine that is already designed to run at 9.5:1 ( or what ever the CR is) I guess what I was trying to say is that is you take your stock engine (or turbo engine for that matter) and boost CR to beyond what it was designed for, it would pop.

[kirk180]

Yes. It would make sense that this is a factor, however, you still need to look at what your total CR is (cylinder CR x boost pressure, not sure of the actual equation)..That's fine. I'm not trying to get into all the reasons for this or that. I's just trying to get on a common ground as far as FSI enabling a car to achieve a higher compression rate than without it.

[bigdyno]

I hope to find some more info on this, I'll let you know if I find anything.

[kirk180]

I hope to find some more info on this, I'll let you know if I find anything.
+1, already did. Found a couple of seemingly reputable reports wrote up on it via the friendly search button.

:wink: