# Stock vs S3 vs RS4 injectors SOME GOOD INFO



## Serrari (Jun 29, 2008)

I dont really get this info:_

More fuel for the fire.We've tested the RS4 injectors during our 2.0T turbo development R&D.
We first tested them in cars, before we purchased our $8000 ASNU DI injector test stand.
When in the car, they produce what looks to be much richer air/fuel ratio vs stock or S3. However, after careful analysis, some odd starting and part throttle behavior was traced to their use.
Upon testing stock, S3, and RS4 injectors in our ASNU test stand, we had some interesting results.
As you can see from the photo below, the spray pattern of the RS4 injector is very different from the stock and S3 injectors. This alone can contribute to the starting and part throttle issues:_









_What was even more interesting were the measured flow rates:
Stock = 1080 cc/min
RS4 = 1091 cc/min
S3 = 1217 cc/min

For all intents and purposes, the RS4 injectors flow about the same as stock 2.0T FSI injectors. This makes sense when you do a hp per cylinder calculation between the two engines. We also confirmed our results after contacting Hitachi directly._ _
The rich air/fuel exhaust reading seems to be an anomaly possibly related to incomplete combustion due to the wrong spray pattern. The peculiarities of direct injection behavior vs conventional injection behavior are still being learned.
Either way, the exhaust gas readings are a false positive as confirmed by our bench testing. Unknowingly, software tuners may be pushing things way leaner than they intended just going off of wideband readings!
What we also found is that a mass marketed transverse K04 kit out there is indeed using RS4 injectors. We had a client come to us with running issues, and a first hand test of his injectors confirmed this.

_*So can the S3 injectors make more power with a good tune?

Anyone knows what is the flow rate on the APR injectors?**

I did heard that spray pattern makes the RS4 a better option, but I dont see how?

USPSMotorsports where going to release a fuel system able to make 700whp, what is the status on that?*


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## Krieger (May 5, 2009)

where did you get that info?

according to this info, the S3 inj. can make more power due to more flow potential.

Also, no, the RS4s will not make more power because of the flow pattern. Apparently the opposite is true since it's not all being burned in the combustion process. I used to think that the RS4s just made everything super rich since ever BT ive seen in person has shot black smoke all over the place, but this makes since if there is a ton of gas going into a focused space, and not being injected in the areas that our engine was designed to use.

idk though, it looks almost like the flow pattern is limited due to maybe some blockage perhaps? I just dont see why it would flow like such a weird pattern and not in a normal fan spray.


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## GolfRS (Feb 4, 2006)

Ding ding ding !!!!

Round two !!!


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## CoNGLoMeRaTeGTi (Apr 4, 2007)

Anyone remember this thread?
http://forums.fourtitude.com/showthread.php?4946733-Big-Turbo-Software&p=66559391&viewfull=1

Or this post?


LEWXCORE said:


> Dude aren't you the same guy that went around ranting about how s3 injectors flow more than rs4's?? forgive me if i'm mistaken. As far as I could see last summer when i built my car, revo advocates and [email protected] informed me that their gt3071 file was not intended to be safe past ~350hp. I believe it was preset to 18psi or so on the n75 and fuel trims were limited. If you're telling me a couple tweeks on the SPS to run as rich as possible and maybe some timing advance for meth can get you up to or past 500 safely then I personally have been very misled by revo and our forum... i might even buy the revo file for chets and gigs if that's a case because getting customer service from uni right now is like watching a bunch of deets trying to fk a doorknob.


heehee

Let's see what else I am right about. Time will only tell.


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## Serrari (Jun 29, 2008)

I just sold my S3 injectors last week, but would like to do some tests...


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## CoNGLoMeRaTeGTi (Apr 4, 2007)

Krieger said:


> where did you get that info?


AWE conducted this experiment.


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## [email protected] (Jul 29, 2008)

CoNGLoMeRaTeGTi said:


> AWE conducted this experiment.


The information they shared is not correct. 

RS4 injectors outflow the S3 injectors when testing at the proper fuel pressure. Their junior injector test stand is not capable of testing at the correct operating pressure. The formula they used to calculate the flow rates at the proper pressure is incorrect.




> So can the S3 injectors make more power with a good tune?


Unmodified S3 injectors are not capable of flowing as much fuel as the RS4 injectors, therefor your potential to make more power on s3 injectors will be lower than RS4 injectors.



> Anyone knows what is the flow rate on the APR injectors?


Sorry, I wish I could share this information with the community but the APR Injectors (Modified S3) is closely protected by our engineering department. 




> I did heard that spray pattern makes the RS4 a better option, but I dont see how


The RS4 Spray patterns is not perfectly designed for the 2.0T FSI and as such has some side effects. Some of the side effects listed above by AWE are not related to the spray pattern. The spray pattern is in no way a benefit and in no way makes it a better option.


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## Serrari (Jun 29, 2008)

[email protected] said:


> Sorry, I wish I could share this information with the community but the APR Injectors (Modified S3) is closely protected by our engineering department.


I think APR would have a huge market to sell those injectors if they can outflow the RS4s. Why haven't you guys think of sell them separately and make lots of money?


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## Krieger (May 5, 2009)

because another company could get their hands on it and do a knock off. It sucks though. Id pick some up with my BT build coming up.


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## FSIGTI (Oct 9, 2006)

Krieger said:


> because another company could get their hands on it and do a knock off. It sucks though. Id pick some up with my BT build coming up.


This cannot be the reason as another company would have already purchased an APR Stage 3 and copied the injectors already..


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## CoNGLoMeRaTeGTi (Apr 4, 2007)

Until someone (individual or company) proves AWEs experiment invalid, I'm still running with their empirical evidence.


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## [email protected] (Oct 23, 2008)

We've been running modified S3 injectors since 06/07... Pag/Tapp GTI runs them


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## Serrari (Jun 29, 2008)

[email protected] said:


> We've been running modified S3 injectors since 06/07... Pag/Tapp GTI runs them


Do you sell them? What are they flow capabilities?


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## alva8193 (May 13, 2009)

[email protected] said:


> We've been running modified S3 injectors since 06/07... Pag/Tapp GTI runs them


im also very curious about this, whats the cost or config?


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## CoNGLoMeRaTeGTi (Apr 4, 2007)

I thought tapp was using modded RS4 injectors


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## [email protected] (Oct 23, 2008)

We had used several different kinds of injectors. At the time (3yrs ago), there wasnt equipment that you can easily acquire to test these injectors. Thinking about building a test fixture in the very near future, but we had opened up the nozzle a certain percentage that allowed us to achieve in the mid 400's. As far as I know, Eurodyne was the first to tune these.


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## EL_3grab (Mar 25, 2006)

[email protected] said:


> We had used several different kinds of injectors. At the time (3yrs ago), there wasnt equipment that you can easily acquire to test these injectors. Thinking about building a test fixture in the very near future these


[email protected] said the only way to have a proper affordable larger injector is to modify the S3

Props to APR of being ahead since 2006, that says a lot :thumbup:


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## [email protected] (Jul 29, 2008)

CoNGLoMeRaTeGTi said:


> Until someone (individual or company) proves AWEs experiment invalid, I'm still running with their empirical evidence.


How bout the hundreds of big turbo cars running RS4 injectors once the S3 injectors became the limiting factor?


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## yvrnycracer (Apr 17, 2007)

this thread needs to be tossed into the black hole... although it could provide some good entertainment like Version 1 did... :laugh::laugh:

And just for consideration... what is the details for the TSI injectors? Seeing that both K04 and Stage 3 kits don't need any sort of upgraded fueling... where are their limits?!


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## rracerguy717 (Apr 8, 2003)

[email protected] said:


> How bout the hundreds of big turbo cars running RS4 injectors once the S3 injectors became the limiting factor?


The rs4 injectors spray pattern will allow you to run a leaner A/F without prob with knock IMO because of the saturation. 

My car on APR 100 octane program spraying very little water in w/m kit pulls little to no timing the 100 octane tune seems alittle leaner (little smoke @ WOT ) compaired to the 93 program (which some times alot of smoke @ WOT). I bet when the air temps are not extreme the 100 octane program will run well in my car with 93 in the tank with the rs4 injectors . 

Arnold taking the car tommorow to freshen the motor up with rings and put a set of his brute rods and coating bearing ,will see how the spray pattern if any effected the inside of the motor after 40K miles with rs4 injectors in place . Then Im ready for future HP uprades ( cams, intake manifold , more aggressive SW. Bob.G


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## Serrari (Jun 29, 2008)

Modified S3 injectors > RS4 injectors?

What about modifying some RS4s?


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## CLestat (Nov 15, 2007)

I belive than USP GTI (3076 and 600 Hp) fit the APR inyectors.


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## IMAN973 (Jun 1, 2006)

CLestat said:


> I belive than USP GTI (3076 and 600 Hp) fit the APR inyectors.


They don't count. Were not talking race fuel numbers just pump and maybe meth.


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## [email protected] (Jul 29, 2008)

Serrari said:


> Modified S3 injectors > RS4 injectors?
> 
> What about modifying some RS4s?


RS4 injectors are laser welded shut. 



yvrnycracer said:


> And just for consideration... what is the details for the TSI injectors? Seeing that both K04 and Stage 3 kits don't need any sort of upgraded fueling... where are their limits?!


TSI has an operating pressure between 150bar and 200 bar.... that gives you a **** ton more headroom compared to the 110-136bar limit on the FSI.


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## LEWXCORE (Jul 7, 2007)

CoNGLoMeRaTeGTi said:


> Anyone remember this thread?
> http://forums.fourtitude.com/showthread.php?4946733-Big-Turbo-Software&p=66559391&viewfull=1
> 
> Or this post?
> ...


Dude AWE posted that Almost 2 years ago, I saw that before I posted that and we all have known from the get that was falsified.. When you run ~130bar the rs4 outflow the s3 by like 100 horsepower.


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## crew219 (Oct 18, 2000)

LEWXCORE said:


> Dude AWE posted that Almost 2 years ago, I saw that before I posted that and we all have known from the get that was falsified.. When you run ~130bar the rs4 outflow the s3 by like 100 horsepower.


:thumbup:

pretty much


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## TTAdict (Aug 3, 2010)

crew219 said:


> :thumbup:
> 
> pretty much


I also do think so because from a technical point of view, if

1) your sensors show you that with RS4 injectors you have more fuel injection
2) your dyno tells you that the engine is producing more power with safe AFR's
3) your diagnostic equipment tells you that everything in the engine is working properly
4) your Exhaust Gas Temperature Gauge shows you lower gas temperatures

then this means that the injectors are larger and do work properly.

If the richer AFR could have ever been attributed to the RS4 injectors different spray pattern,
that would mean:

1. that the combustion chamber would have very very uneven thermal load
2. there would be hot spots on a very wide area of the piston and the cylinder head, hence knocking
3. the piston would have melted long before the engine could produce 450hp+ at the crankshaft



A few examples from big turbo kits:

* Audi A3 2.0 TFSI http://www.etuners.gr/en/index.php?s=13&t=214
* Skoda Octavia 5 RS 2.0 TFSI http://www.etuners.gr/en/index.php?s=13&t=215
* VW Golf 5 GTI 2.0 TFSI http://www.etuners.gr/en/index.php?s=13&t=207


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## LEWXCORE (Jul 7, 2007)

TTAdict said:


> I also do think so because from a technical point of view, if
> 
> 1) your sensors show you that with RS4 injectors you have more fuel injection
> 2) your dyno tells you that the engine is producing more power with safe AFR's
> ...


Even the village idiots understand by now that the RS4 outflow the S3. People are making 500+ left and right with rs4+meth and s3 aren't really getting people anywhere. Only thing that sucks about the rs4 is that warmup can be wierd at times and the first mile or two of driving. Maybe that's just my tune or something but i've experienced these symptoms since day 1. Car feels very healthy about a mile or so into driving from a cold start though. The only thing that sucks now is that new fsi injectors are a different design and won't bolt on. Another oem option that could flow enough for 600hp or so would be king and push this platform so much further in a simple way. E85 conversions, higher boost, bigger turbos, bigger numbers, Then everything else gets developed more and more people jump aboard. It's a shame it really is.


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## V8mgbgt (Jan 4, 2015)

*RS4 flow rates versus pressure*

Hi
These RS4 injectors have impressive flow rates in excess of 1,000cc at high pressure.

Do anyone have any flow rates for these injectors at pressures as low as 7 bar. Odd request I know but looking to use some on another application.

Thanks


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## vtraudt (Mar 1, 2010)

[email protected] said:


> TSI has an operating pressure between 150bar and 200 bar.... that gives you a **** ton more headroom compared to the 110-136bar limit on the FSI.


What years/engine codes are TSI, which are FSI?
Since fuel=power, what are the limits of the respective fuel pumps? 
Looking at stage 2 tuned charts (stock otherwise) power curve flattens from 4700 rpm and up. Is the stock K03 running out of breath, or is fueling running out?


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## vtraudt (Mar 1, 2010)

vtraudt said:


> What years/engine codes are TSI, which are FSI?


I think I found my answer:
2005.5-2008.5: FSI EA113 engine (lower pressure pump)
2008.5-2013.5: TSI EA888 engine (higher pressure pump)


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## JaxACR (Dec 6, 2007)

vtraudt said:


> I think I found my answer:
> 2005.5-2008.5: FSI EA113 engine (lower pressure pump)
> 2008.5-2013.5: TSI EA888 engine (higher pressure pump)


Right, the only exceptions in 2008.5-up being the high output variants (TT-S, Golf R, S3) which still use the EA113 with stronger internals. The HPFP is the same as the lower output models, but the cam that the HPFP runs on may have a different profile to alter output. Seems like there's conflicting info about this though.


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## Allyn (Dec 23, 2001)

LEWXCORE said:


> Even the village idiots understand by now that the RS4 outflow the S3.


...so this has been bugging me for a while now. I'm not trying to argue that folks can or can't make more power with the RS4 injectors as that seems more or less proven, but what I don't understand is why the math doesn't work out. Injectors are commonly flow tested at 5 bar, with that pressure actually called for in many factory / manufacturer test procedures (yes, even for FSI injectors). Injector flow rate, when adjusting for a different pressure than measured, is proportional to the square of the pressure difference. That being the case, how can we have the original poster measure greater flow from S3 injectors at a specified pressure, but then APR (Arin) chimes in and claims that at higher pressures the S3 injector actually flows less. What is it about the RS4 injectors that enables them to violate the laws of physics that apply to flow nozzles? Not trying to be sarcastic here, I genuinely want to know what accounts for this difference of opinion / fact here, because the math (or the actual injector physics) just isn't working out as it should be.


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## [email protected] (Jul 29, 2008)

The short answer is the flow rate isn't linear. You can't test them at 5 bar and make accurate assumptions for 100, 130, 150 bar, etc. It's a curve and different for each injector.


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## filthyillness (Feb 13, 2010)

Stock injectors are good up to around the 350hp range. All these injector swaps are just to settle peoples minds. Keep your fuel system clean and you won't have any issues unless you're going BT (above k04).


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## schumacher_peng (Aug 18, 2016)

If I'm going to build a high rpm (ie 8000rpm) NA FSI engine ,do I need to go for the RS4 injectors?


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## Sugar Bear (Jul 17, 2016)

filthyillness said:


> Stock injectors are good up to around the 350hp range. All these injector swaps are just to settle peoples minds. Keep your fuel system clean and you won't have any issues unless you're going BT (above k04).


anyone else second this?


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## NitrousOxide (Dec 5, 2017)

[email protected] said:


> We've been running modified S3 injectors since 06/07... Pag/Tapp GTI runs them


http://pagparts.com/product_info.php?cPath=79_107_127&products_id=308

Is this being sold above, modified? May I have the OEM part number?


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## jed02gtiguy (Mar 30, 2002)

*let me know what you come up with*

let me know what you hear.


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## NitrousOxide (Dec 5, 2017)

I'm just doing a K03 -> F23T turbo upgrade. I'm just looking for a fueling option that gives me 290-300whp on my daily driven MK5 GTI.

I only went with the F23T to fill the areas where the K03 tapers off.


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## NitrousOxide (Dec 5, 2017)

*Injector constant query*

Can someone tell me what the injector constant is for the S3 injector with Bosch part number: 0261500037
This would be for a 4-cylinder 1984 cc block


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