# USP Presents the FSI Low Pressure fuel solution, for you High Horsepower Guys!



## [email protected] (Oct 30, 2008)

*Introduction:*
As many of you know the fuel system for the 2.0T FSI platform is composed of two separate systems, the high pressure system and the low pressure system. While, the limitations of high pressure fuel delivery have been eliminated by products such as the APR upgraded rail pump, the low pressure system has been ignored. 
Through our testing we were able to determine that the low pressure fuel system is nearly maxed out when producing around 350whp, running an a/f ratio between 11.0:1 – 11.5:1. This limitation is a result of the in-tank fuel pump being maxed out. By replacing the factory in-tank fuel pump with an APR in-tank fuel pump, the low pressure fuel system sits on its limits at around 400whp, while still maintaining the same a/f ratio mentioned above.
Developing a low pressure fuel system to work properly with the complicated components and electronics of the 2.0T FSI was no easy task. The in-tank fuel pump that runs the FSI does not function like a traditional fuel pump. Meaning, the fuel pump does not always receive a full 12volt signal while the car is running like a traditional fuel pump does. Instead, the ECM controls the fuel pump through a Pulse-Width Modulated signal (PWM). This quickly ruled out the ability to add an inline fuel pump. Other options were explored but, adding a secondary in-tank fuel pump was the end result.

*Function:*
The main purpose of the USP Motorsports auxiliary fuel system is to provide enough fuel flow to the high pressure fuel pump to support 400+ horsepower safely. This was done by incorporating a secondary in-tank fuel pump that alone can support 600 horsepower. However, incorporating a secondary in-tank fuel pump by itself will not function properly as the FSI low pressure fuel system is return-less. To combat this issue USP Motorsports created a load-based fuel pump controller. The result is the secondary fuel pump only being turned on when it is needed. 
This system is estimated to be good for around 700 wheel horsepower and is the same system used on our in-house MK5 GTI which produces 605whp. 

*What is included:*
• High flow in-tank fuel pump
• Load-based fuel pump controller
• Preassembled fuel lines
• OEM Crimp style clamps
• Fuel distribution block 
• Fuel Tank bulkhead assembly
• All wires, terminals, and connectors
•Detailed instructions​









*FAQs*

What does this system do?
This system picks up where the factory low pressure fuel system left off. It provides the high pressure fuel pump with the needed fuel to achieve a high horsepower FSI motor.

How does this system work?
Your factory low pressure fuel system stays intact. The USP fuel system is added within the fuel tank to supplement the factory pump. The pump works off a load based controller so the added fuel is supplied only when it is needed.

How much power can this system handle?
This system has been tested on our in house GTI to 605whp and based on flow calculations should be good for 700whp.

How long does installation take?
Installation can be performed in around 2 hours. 

I see other FSI cars making around 400whp without this, how is that possible?
There are a few ways. One way is that the car is running a dangerously high air fuel ratio. We have seen this on several local customers’ cars. We have seen a/f ratios as lean as 13:1 on pump gas under full boost. This is extremely dangerous and robs horsepower from the FSI motor. The second way is that they are simply making up the lack of fuel by using methanol injection. This can be extremely dangerous as well because most kits do not have a failsafe if one of the many components in the methanol kits stops functioning.

I am located outside the U.S., how do I place my order?
Please email me at [email protected] so I can provide a shipping quote.

I have a question, how can I get an answer?
Feel free to email me at [email protected]

*At this time this kit is only available for FWD GTI, GLI, A3, and TT*
*Pricing and order information:*

*Retail pricing is $525*
*Vortex special $475 shipped within the U.S.*
Add APR in-tank fuel pump $199 (FWD only)
*Click here to order your low pressure fuel pump kit for $425 shipped. Be sure to use coupon code “lean-is-mean” at checkout.*


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## bwoodahl (Dec 13, 2007)

Good stuff. What's the difference between your "High flow in-tank fuel pump" and APR's in-tank fuel pump (for the additional $199)


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## [email protected] (Oct 30, 2008)

bwoodahl said:


> Good stuff. What's the difference between your "High flow in-tank fuel pump" and APR's in-tank fuel pump (for the additional $199)


the apr intank pump replaces the primary fuel pump in the tank.


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## LEWXCORE (Jul 7, 2007)

Gregg you know those sniffers might be a little bit off at times LOL i was running lean but not THAT lean.. maybe high 12s. i would have blown my motor by now because i'm running those boost levels on the street but wideband is reading high 11's- maybe 12.0 or 12.1 on 30psi with a larger quantity of meth. I agree this is dangerous though, relying on that much meth. 

Anyone interested in this kit i would highly recommend it for the safety of your motor, plus Id trust anything usp is offering, top notch quality and service.

I'll prob go with this solution after i see what happens with the APR intank and rs4 fuel rail valve.. hoping to flow more fuel then but i'll need more to really crank the boost on the 5857


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## [email protected] (Oct 30, 2008)

LEWXCORE said:


> Gregg you know those sniffers might be a little bit off at times LOL i was running lean but not THAT lean.. maybe high 12s. i would have blown my motor by now because i'm running those boost levels on the street but wideband is reading high 11's- maybe 12.0 or 12.1 on 30psi with a larger quantity of meth. I agree this is dangerous though, relying on that much meth.
> 
> Anyone interested in this kit i would highly recommend it for the safety of your motor, plus Id trust anything usp is offering, top notch quality and service.
> 
> I'll prob go with this solution after i see what happens with the APR intank and rs4 fuel rail valve.. hoping to flow more fuel then but i'll need more to really crank the boost on the 5857


I was not referring to your car  We have seen others down here that ran that lean


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## CoNGLoMeRaTeGTi (Apr 4, 2007)

This isn't much of a solution. It's just like a WMI system. A hobb switch ran pump. 

Instead of pumping WM it's pumping gasoline. 

A solution would be a drop in solution that runs off of PWM. 

There are two real drop in solutions. One being the APR unit and the other is a unit that has yet to be completely tested yet.


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## bwoodahl (Dec 13, 2007)

I was wondering if this USP set-up is redundant (and therefore not necessary) for those that already have the APR in-tank pump?


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## [email protected] (Oct 30, 2008)

CoNGLoMeRaTeGTi said:


> This isn't much of a solution. It's just like a WMI system. A hobb switch ran pump.
> 
> Instead of pumping WM it's pumping gasoline.
> 
> ...


Its a little more complicated then a hobbs switch. For not being much of a solution it sure works for us. FYI the APR unit wont bring you past 450whp and that is if you are running a lower compression ratio.


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## CoNGLoMeRaTeGTi (Apr 4, 2007)

12.5 is stoich. 

We all know the FSI is capable of doing things with fueling that a conventional EFI Otto engine. 

Who knows how lean we can really make these engines go?

Trial and error is really the only way. 

I had 11.5 AFR when I had my 100% stock fueling and WMI on my old 28RS setup and was able to make 330whp. Seems like nothing, but the fact that my fueling was 100% stock, with the exception on WMI speaks volumes about the capabilities of the FSI technology. 

I'm shooting for 450whp on stock LPFP. Then 500whp on a LPFP I've been playing around with lately.


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## [email protected] (Oct 30, 2008)

CoNGLoMeRaTeGTi said:


> 12.5 is stoich.
> 
> We all know the FSI is capable of doing things with fueling that a conventional EFI Otto engine.
> 
> ...


We played around with my car a lot and we saw power loss with anything leaner than 12.3:1 FYI stoichiometric mixture of air and fuel is 14.7:1 anything less is consider rich anything more is lean. This definition of rich and lean is of course from a scientific stand point.


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## LEWXCORE (Jul 7, 2007)

not redundant because the APR in-tank isn't even included in this setup, it's just an option that will support maybe around another 50hp worth of fuel (correct me if i'm wrong.)

The thing here is that this incorporates a secondary in-tank fuel pump (the one that runs off the switch) that will flow more than possible for the apr in-tank pump alone to the fuel rail... the question now once we get to this point though of course is: how much can you make on the rs4 injectors before they themselves are maxxed out on this setup?


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## IMAN973 (Jun 1, 2006)

LEWXCORE said:


> not redundant because the APR in-tank isn't even included in this setup, it's just an option that will support maybe around another 50hp worth of fuel (correct me if i'm wrong.)
> 
> The thing here is that this incorporates a secondary in-tank fuel pump (the one that runs off the switch) that will flow more than possible for the apr in-tank pump alone to the fuel rail... the question now once we get to this point though of course is: how much can you make on the rs4 injectors before they themselves are maxxed out on this setup?


450hp tops with regular pump gas, not c16


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## LEWXCORE (Jul 7, 2007)

that's the important detail we're leaving out here.. injectors themselves do not support the high hp.


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## Hendrik (Sep 13, 2008)

I remember a thread, Gregg said that they are maxed out at approx. 470whp on pump!


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## LEWXCORE (Jul 7, 2007)

lol i'd say that's close to 600 on pump and meth considering what people are making with stock low pressure and meth.. if a bigger injector option was available we'd see alot bigger numbers everywhere.


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## Hendrik (Sep 13, 2008)

I wrote on pump  

...it´s 1 year ago and referred to 130bar FP and not 136 with the RS4 valve... 
with meth there is a lot more possible, sure!


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## IMAN973 (Jun 1, 2006)

So is this the same kit thats been around for years through USP or has there been a revision and hence this thread?


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## CoNGLoMeRaTeGTi (Apr 4, 2007)

LEWXCORE said:


> lol i'd say that's close to 600 on pump and meth considering what people are making with stock low pressure and meth.. if a bigger injector option was available we'd see alot bigger numbers everywhere.


Why bother with larger injectors?

Just run C16 or Q16.


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## FSIGTI (Oct 9, 2006)

CoNGLoMeRaTeGTi said:


> Why bother with larger injectors?
> 
> Just run C16 or Q16.


How much is that a gallon for a DD


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## CoNGLoMeRaTeGTi (Apr 4, 2007)

16 dollars a gallon, but who DD 600hp. You can run 24psi on 93 and make decent power for DD.anThem 30+ on 116 octane. 

This would be great for someone with a billet set up. Even better for someone with Revo that can actually advance the timing with the revo switch.


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## [email protected] (Oct 30, 2008)

IMAN973 said:


> So is this the same kit thats been around for years through USP or has there been a revision and hence this thread?


it has been redone for production


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## [email protected] (Oct 30, 2008)

all orders have shipped


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## marc1171 (Nov 19, 2008)

we are installing this USP system RIGHT NOW on mine  top notch quality i must say! 
ill let you all know the HP numbers ill get and how far the RS4's will go...


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## Serrari (Jun 29, 2008)

[email protected] said:


> it has been redone for production


What has changed?


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## [email protected] (Oct 30, 2008)

Serrari said:


> What has changed?


the fitting going into the fuel tank for the wires, the lines and merge fitting, and some changes to the pump controller


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## vwguy13 (Oct 5, 2008)

was there any problems with the old set up?


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## [email protected] (Oct 30, 2008)

vwguy13 said:


> was there any problems with the old set up?


no, there was nothing wrong with it, we just found a way to manufacture them faster and offer them to the consumer at a lower price.


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## [email protected] (Oct 30, 2008)

Just shipped 3 out yesterday. Get yours and make some horsepower


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## Serrari (Jun 29, 2008)

After several tries I cant get the pumps inside the tank. They dont fit in that little hole. Do you have more detailed instructions or how do I get it in?


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## [email protected] (Oct 30, 2008)

Serrari said:


> After several tries I cant get the pumps inside the tank. They dont fit in that little hole. Do you have more detailed instructions or how do I get it in?


just sent you an email earlier today


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## [email protected] (Oct 30, 2008)

more kits are instock and ready to ship


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## Serrari (Jun 29, 2008)

Why would you run auxiliary injectors on your setup to get 600whp when you have this kit?


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## [email protected] (Oct 30, 2008)

Serrari said:


> Why would you run auxiliary injectors on your setup to get 600whp when you have this kit?


We only ran the auxiliary injectors when we ran the car on E85


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## Serrari (Jun 29, 2008)

[email protected] said:


> We only ran the auxiliary injectors when we ran the car on E85


Ok, have you dynoed your car on race gas without auxiliary injectors?


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## Serrari (Jun 29, 2008)




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## Serrari (Jun 29, 2008)

No answer? 

I just want to know how was the USP low pressure fuel system tested to 700hp without additional injectors.


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## $GTI07$ (Feb 29, 2008)

i dont think ups does any fsi low pressure pumps? lol you mean usp!!


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## [email protected] (Oct 30, 2008)

Serrari said:


> No answer?
> 
> I just want to know how was the USP low pressure fuel system tested to 700hp without additional injectors.


we made 605whp with this fuel system with NO additional injectors. The additional injectors were added when we tuned the car for E85


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## Serrari (Jun 29, 2008)

[email protected] said:


> we made 605whp with this fuel system with NO additional injectors. The additional injectors were added when we tuned the car for E85


Thanks Gregg, just wanted to be sure. :thumbup:


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## axthomson (Jul 8, 2006)

A little off topic, but how did the car run on E85? and how much power did it make?


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## amckernon1028 (Apr 14, 2009)

Would I see any gains by adding this to my APR KO4 setup? Or are my S3 injectors maxed and therefor no gains would be made?


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## [email protected] (Oct 30, 2008)

axthomson said:


> A little off topic, but how did the car run on E85? and how much power did it make?


The car ran actually pretty well except for cold starts, it made right around the same power as race gas but was $15 cheaper per gallon 



amckernon1028 said:


> Would I see any gains by adding this to my APR KO4 setup? Or are my S3 injectors maxed and therefor no gains would be made?


At K04 power levels you really won't see a difference.


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## [email protected] (Oct 30, 2008)

should have more ready to ship early next week


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## [email protected] (Oct 30, 2008)

production batch is done, and they are ready to ship


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