anyone notice APR developed an FSI fuel pump?
10-07-2007, 02:01 PM
#1
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anyone notice APR developed an FSI fuel pump?
...it's for the 2.0TFSI, but this has me wondering if our 4.2FSI might benefit from a similar approach. Maybe once we have some chip-tuning available to work with our free-flowing exhausts...then there might be a reason to get more fuel into the motor.
<a href="http://www.goapr.com/Audi/products/fsi_fuel_pump.html">click</a>
<a href="http://www.goapr.com/Audi/products/fsi_fuel_pump.html">click</a>
10-07-2007, 04:43 PM
#2
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It won't be need unless you go to N2O or forced induction.
There is always considerable headroom built into an OEM fuel system.
The fact that MTM can get 500+ horsepower on the stock injectors/pump with their supercharger backs this up.
It would be all but impossible to outflow the stock fuel system normally aspirated IMO.
The fact that MTM can get 500+ horsepower on the stock injectors/pump with their supercharger backs this up.
It would be all but impossible to outflow the stock fuel system normally aspirated IMO.
10-07-2007, 07:07 PM
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You would only make more power if your current system was beyond maxed out...
and running too lean.
I have no proof, but I can promise you MTM doesn't tune that way...not to mention the RS4 engine on stock internals would have a rather short lifespan if you really were on the ragged edge in terms of A/F ratio.
By design, the RS4 likely has a similar fuel "headroom" % when compared to a stock 2.0T FSI engine. If you look at APR's graph, you can see the stock fuel pump is good for ~35% over stock horsepower at the very least. In most cases, much more.
I don't think we'll every see an RS4 making that kind of extra power, at least not until someone slaps some turbos on one.
I have no proof, but I can promise you MTM doesn't tune that way...not to mention the RS4 engine on stock internals would have a rather short lifespan if you really were on the ragged edge in terms of A/F ratio.
By design, the RS4 likely has a similar fuel "headroom" % when compared to a stock 2.0T FSI engine. If you look at APR's graph, you can see the stock fuel pump is good for ~35% over stock horsepower at the very least. In most cases, much more.
I don't think we'll every see an RS4 making that kind of extra power, at least not until someone slaps some turbos on one.
10-07-2007, 08:18 PM
#5
Doubt it. They're using it for 280tq+ apps on the 2.0t FSI. You have two pumps on the 4.2 FSI...
so i'd bet you have enough fuel for the bit of power exhaust and chips will give. The 2.0TFSI will just about double it's power in the big turbo applications that are using the pump and the main purpose for the FSI pump upgrade is it's difficulty keeping up with instant torque demands not overall flow. The S4/RS4 and other non turbo apps shouldnt have this problem. THey ramp up progressively. Where the 2.0T fsi has problems is the way that due to being boosted you can get max torque at the push of the throttle at, say, 4000rpm. The pumps dont keep up with that.
10-07-2007, 09:34 PM
#6
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well they're saying it's good for 350hp on the 2.0T, so not quite double, but...
...obviously there would have to be other mods to exploit the extra fuel delivery...cams and full exhaust at a minimum. Maybe a displacement increase, which I don't think anyone has attempted with the 4.2. Just thinking out loud...
10-07-2007, 09:38 PM
#7
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that's why I mentioned the Champion car...
...we don't know how they're getting (allegedly) 500hp out of it. Stock displacement...cams? exhaust (we know it's fully open), race fuel & chip tuning, stock airbox...what else?
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10-07-2007, 09:53 PM
#8
They are conservative. Folks are already making close to 400hp on the 1.8t APR stage 3....
Some are making over 400hp on them with tweaks. The 2.0T stage 3 runs stock internals in it's plug and play form. It necessitates injectors, pump, turbo, manifold, full exhaust, and optional but recommended would be intercooler and clutch. Either way, I guess that's not important because the fuel pump will also be used on the small K04 upgrade and even the maxed out k03 (OEM turbo) setups. I ran into fuel cuts on my k03 and my k04 setup on my 2006 2.0t FSI and all tuners are tuning around that issue for now until the fuel pumps are out.
The real problem with the pump though is not just flow, but response. This is actually a problem they are having on the stock pump on just chipped cars and the little K04 turbo upgraded FSI cars like I had. More so on these setups becaues the smaller turbos spool so damn fast instead of ramping up slowly like the big turbos to. The small turbo can easily make peak boost at 3000rpm or so. So if you are driving along at 4000rpm and you go from no load to full load the turbo will instantly spike up to peak boost at 20psi or so as it should and the fuel system is now having to keep up with an instant 300lb torque demand. The NA cars don't seem to be having this problem.
For the RS4, you can check this by logging the fuel pressure under very demanding no load/full load transitions flat in upper gears (4th or 5th) at about 4000rpm to 5500rpm. You should see stable fuel pressure. You can log injector on0time as well to see how much headroom you have there.
The real problem with the pump though is not just flow, but response. This is actually a problem they are having on the stock pump on just chipped cars and the little K04 turbo upgraded FSI cars like I had. More so on these setups becaues the smaller turbos spool so damn fast instead of ramping up slowly like the big turbos to. The small turbo can easily make peak boost at 3000rpm or so. So if you are driving along at 4000rpm and you go from no load to full load the turbo will instantly spike up to peak boost at 20psi or so as it should and the fuel system is now having to keep up with an instant 300lb torque demand. The NA cars don't seem to be having this problem.
For the RS4, you can check this by logging the fuel pressure under very demanding no load/full load transitions flat in upper gears (4th or 5th) at about 4000rpm to 5500rpm. You should see stable fuel pressure. You can log injector on0time as well to see how much headroom you have there.
10-08-2007, 02:31 AM
#9
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Increasing the displacement wouldn't work well on these cars...
Increasing the stroke would require a reduction of revs, it's already got F1 mean piston speeds.
The bore spacing is already unusually small, and you'd have to have the block re-etched with Alusil.
It'd just be a bad idea IMO.
The bore spacing is already unusually small, and you'd have to have the block re-etched with Alusil.
It'd just be a bad idea IMO.
10-08-2007, 07:33 AM
#10
They state stock internals. looks like stock fuel pumps to me.
<center><img src="https://www.audiworld.com/news/07/alms-vitesse-rs4/header2.jpg"></center><p># The engine is a stock RS4 engine with identical internals to the RS4 available from Audi dealerships - even running a stock airbox and air filter
# The engine management system has been modified
# The exhaust system is comprised of custom built headers and straight pipes; there are no catalytic converters and no mufflers
# Engine output is rated at around 500 hp
# The engine management system has been modified
# The exhaust system is comprised of custom built headers and straight pipes; there are no catalytic converters and no mufflers
# Engine output is rated at around 500 hp