RS4, RS6 or TTRS injectors on 2.0 TFSI BT ?

A4_DTM

Registered User
I'm building BT kit on my car, it will consist of Garrett GT3076R .82 A/R and custom manifold. I'm not shure what injectors to put in it ? If I stay on stock S3, I will probably see 390HP but that is optimistic because my tuner is tuning on MAHA 3000 with very strong load which probably never happens on the road. He is not very happy with RS4 injectors because they don't disperse gas like S3 injectors do. This is test of them on the "table" LINK

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:
FSI_injectors_comparo.jpg


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.
Are there any other injectors that have same impedance as S3 and that they flow more gas at 110 bar ? For example RS6 or TTRS injectors that are designed for turbo engine ?
 
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warren_S5

Moderator
Moderator
VCDS Map User
I thought the S3 injectors were good for nearly 400bhp??

What kind of power are you looking for in your car?

There's a bloke on VAGOC whose signature states he has 500bhp but I have no idea what injectors he's running.
 

A4_DTM

Registered User
Well now it will have about 400hp because I don't want to go over that on stock engine (for now :) )... but I don't want that injectors are working on 99% of their capatibilitys so that is why I would like to install some other injectors
 

KRL

Registered User
My understanding was that the RS4 injectors should be good. REVO recommend the RS4 and R8 injectors for their stage 3 software on the S3. Here are REVO's HW requirements:
Required Hardware
GT3071R Turbo plus installation components
VAG RS4/R8 spec injectors
Cold Air intake (from turbo inlet pipe to front of car replacing factory airbox for best gains)
3.0"Turbo back exhaust without pre-cat and with decat or highflow catalytic convertor (DP comes with turbo kit)
Uprated or additional Intercooler
Uprated High Pressure Fuel Pump

I do not have any experience of the RS4 injectors myself but I know that JonnyC has been running them and not had any issues at silly BHP.
 

KRL

Registered User
APR do make their own injectors as well which are supplied with their stage 3 kit. They should be good for 500 BHP:

20ts3_injectors.jpg


APR Injectors

APR includes another unmatched achievement in FSI fueling technology by way of our uprated injectors that provide more fuel than any other available FSI injector. Early on in FSI development with VWGoA for the RGTi, APR's engineers determined the future of FSI performance modifications would require flow rates capable of achieving 500hp. APR set out to form strategic relationships with Tier 1 suppliers to the OEM's to develop processes and controls for a larger FSI injector. After 2 years of refinement, APR is proud to offer these injectors in our Stage III turbocharger upgrade systems for the first time to the general public.

I do not think they are available separately to the stage 3 kit though.
 

akash_sky1

Registered User
I would have thought injectors designed to run in a forced induction engine such as in TT-RS would be much more suitable. With an engine that has both high compression ratio and pressurized intake I woudn't have thought injectors designed for an N/A would be capable of proper distribution thru more highly pressurized gas.
 

A4_DTM

Registered User
I would have thought injectors designed to run in a forced induction engine such as in TT-RS would be much more suitable. With an engine that has both high compression ratio and pressurized intake I woudn't have thought injectors designed for an N/A would be capable of proper distribution thru more highly pressurized gas.

Just checked with jonnyc, TTRS and RS6 injectors don't fit :(
 

PH1L

Gievf Buckets
dans s3 (the vagoc one talked about) is running rs4 injectors with over 500bhp
 

Unitronic

Fear is just a word!
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.

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.


The RS4 Spray patterns is not perfectly designed for the 2.0T FSI and as such has some side effects. The spray pattern is in no way a benefit and in no way makes it a better option. :s3addict:
 

S3Alex

Rarely neutral
Gold Supporter
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.

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.


The RS4 Spray patterns is not perfectly designed for the 2.0T FSI and as such has some side effects. The spray pattern is in no way a benefit and in no way makes it a better option. :s3addict:

Thread exhumation!

I agree that the RS4 injectors at correct pressures are capable of flowing significantly more fuel,and those of us running RS4 injectors with big turbos have found them to be capable of over 500bhp,and probably up to 580bhp before they start to hit the limits,after which you need something like a Stg2 Sorensen manifold with extra injectors and off board ECU.

For sure also,the spray pattern is not optimal,and this is something that APR used to make much of when bashing them,but depsite that,they do work,and there are few alternatives.
 

grainqey

Registered User
Thread exhumation!

I agree that the RS4 injectors at correct pressures are capable of flowing significantly more fuel,and those of us running RS4 injectors with big turbos have found them to be capable of over 500bhp,and probably up to 580bhp before they start to hit the limits,after which you need something like a Stg2 Sorensen manifold with extra injectors and off board ECU.

For sure also,the spray pattern is not optimal,and this is something that APR used to make much of when bashing them,but depsite that,they do work,and there are few alternatives.

Holy zombie undead thread resurrection....

I've been looking at the new 4.0tfsi V8 injectors and TTRS injectors but nobody seems to have any information on the actual flow rate or spray pattern. The TTRS are supposed to flow 30% more than the S3 ones and I'm presuming they are the correct flow which is fine but I can get a set of 8 of the 4.0TFSI injectors which should be plenty based on what VFS on facebook advertise....
From facebook, VFS - vag fueling solutions supply the new 4.0tfsi injectors for anything from 400-500bhp and TTRS/RS3 from 500bhp upwards

Does anybody know anything about this?
 

grainqey

Registered User
I'll have to see what Rick says,

I'm half tempted to swap from my current tuner to Rick when I go big turbo so i'll have to see what he says, not a million miles difference between my current tuner and Rick as I'm only over the woodhead from him!

Thanks
 

S3Alex

Rarely neutral
Gold Supporter
I'll have to see what Rick says,

I'm half tempted to swap from my current tuner to Rick when I go big turbo so i'll have to see what he says, not a million miles difference between my current tuner and Rick as I'm only over the woodhead from him!

Thanks

I think unless you want something like mine then Rick would be an excellent choice.

He can get the best from the stock ECU and the various injector and LPFP options.

Otherwise....one word.

Syvecs.
 

grainqey

Registered User
I'd rather stay with the stock ecu but that may end up being a problem depending how mental I go haha!

I'm only FWD - although my tuner always asks if mine is Quattro when I have dyno runs lol

I'll drop him a PM about the injectors and see what he says

Thanks
 

Inertiauk

Registered User
Do these plug straight in ? Or do you need a loom / adaptor ?
Best place to source the 8v injectors ? Which fuel return valve ? (Stock is fine I presume due to upgrades injectors).

Thanks!
 

grainqey

Registered User
you have to repin (swap) the 2.0 TFSI connectors to the RS3 ones on the loom - the pins are the opposite way round too from what I've been told
 

scotty2hotty

Registered User
I'm in the middle of fitting rs3 injectors and have just noticed you mention the pins are the opposite way round? Is this a definite? And I assume they can't go any way round?
 

scotty2hotty

Registered User
Thanks for your reply and I was thinking it might not matter but still spent over an hour trying to find pictures of the plugs and wires.

Anyway I got it running this morning so hopefully it's all good
 

Dan Maguire

Registered User
I want upgrade my injectors on my Audi s3 8p do rs3 8v injectors fit just seen advert on eBay he said he had them in and the low pressure fuel pump ?
 

nluk100

Registered User
You need to re-wire the pins on the loom for RS3 8V injectors. Plus you will need a custom map for them too or they will most likely run rich.

I had RS4 B7 injectors in my BT S3 - they are good for 450bhp+, however they do cause the car to becoming more difficult to start (2-3 seconds to fire rather than the usual 1 second). No issues with part throttle response - this is down to how the tuner maps the car for them.

Stock injectors struggle above 390bhp on a realistic dyno.
 

Dan Maguire

Registered User
thanks for your replay just after abit more power 360bhp now going to Germany in couple weeks might just leave it standard ones in until I do turbo upgrade.
 

samuelh_888

Registered User
You don’t need to upgrade your injectors for a little more power. The stock items easily handle 380bhp, unless your going for a big turbo. Depending on the turbo, RS3 injectors with the AKS head mod receives great feedback in this forum and turning circles.
 

paddy

Registered User
Dan..in my experience half the battle with tuning is sorting out whats value for money and whats no real advantage.
You dont need uprated injectors at 360 or 380 BHP as Sam has said.
 
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