175 Bar PRV?!?!

[StatusQuo]

http://www.akstuning.co.uk/engine-co..._valve-175_bar

Apparently this supports 175bar. Anyone confirm?

Any potential dangers running this?

[Audibot]

Probably not. I had the RS4 155 PRV on my A4 from hpfpupgrade and had no issues at all.

[james12lucy]

The danger is paying too much. This is grossly overpriced for what you're getting.


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[StatusQuo]

is 160 euro too much considering the HPFPupgrade ones go for 200 usd for the 155bar?

[aluthman]

I'm running a 165 bar HPFPupgrade PRV. It was a custom order and wasn't cheap. I would have bought this one in a heartbeat.

[StatusQuo]

Hey aluth are you able to hit over 160 bar on it?



I also have an idea. I've been thinking about it for the last few days. I'm thinking of putting a brass bolt in place of the PRV and block it off completely. Would also remove an inherent complication of the fuel system.


The ECU controls the pressure anyways. The lines should be good for over 200bar. But 165/175 bar commanded is safe because you can get PRVs made as such. I know there is a safety aspect but I feel the valve is there for legal/liability reasons.


Just thinking aloud here.

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[p0isin]

You will get MASSIVE spikes in fuel pressure if you don't have a PRV and just block it off instead. Just run a PRV. What are your plans that you need 175 bar on the high pressure fuel line?

[aluthman]

I haven't tried yet. The original plan was to run a 155 bar rail pressure. I've since started down the path of port injection, so that may not ever happen. I'm not sure blocking it off is the best idea. It may work just fine, but the potential consequences of things going wrong involve a rather large fireball.

[aluthman]

You will get MASSIVE spikes in fuel pressure if you don't have a PRV and just block it off instead. Just run a PRV. What are your plans that you need 175 bar on the high pressure fuel line?

I forgot about this part. When rapidly cutting the throttle after a WOT run, my old car would always spike to the PRV set pressure in logs. Who knows how high it would go if there was a bolt there instead.

[StatusQuo]

Thanks for clearing this up guys. I was thinking about the liftoff spikes but wasn't sure it would controlled or not. Guess I was wrong lol.


Anyways, the reason I'm trying to run 175bar is that I'm trying to pair it with RS4 injectors so I can run e85 with my big turbo. Hopefully get enough flow..

I'm trying to avoid the more exotic auxillary fueling common on the platform. Cali has only 91 and I'm terrified of knock.

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[Okedokey]

Use S3 injectors mate. RS4 ones have an incompatible spray pattern.

[aluthman]

Thanks for clearing this up guys. I was thinking about the liftoff spikes but wasn't sure it would controlled or not. Guess I was wrong lol.


Anyways, the reason I'm trying to run 175bar is that I'm trying to pair it with RS4 injectors so I can run e85 with my big turbo. Hopefully get enough flow..

I'm trying to avoid the more exotic auxillary fueling common on the platform. Cali has only 91 and I'm terrified of knock.

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You can max out RS4 injectors at 155 bar with a K04 on E85.

[StatusQuo]

Damn smh lol.

Has anyone tried TTRS TFSI injectors???

I haven't seen anyone run em. Do they fit?

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[p0isin]

I have a built motor with a gtx2867r, dw300c lpfp, IE hpfp, s3 injectors, and 155 bar PRV. Even with 93 octane and 145 bar on the high pressure line I get up around 10ms injection time.

S3 or rs4 injectors probably won't hold up to a big turbo on e85

- - - Updated - - -

Damn smh lol.

Has anyone tried TTRS TFSI injectors???

I haven't seen anyone run em. Do they fit?

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Ericpaulyoung may have been playing around with those injectors. Better spray pattern if they are the ones I'm thinking of, just not sure on their flow rates.

[Gotpsi2008]

Is there any point to upgrade the PRV if your still stock injectors?

[p0isin]

Is there any point to upgrade the PRV if your still stock injectors?

It won't do much. Maybe if your tune calls for it for some reason (e85) and you have an upgraded hpfp. But on k03 it shouldn't be needed

[StatusQuo]

Is there a possibility of rotating the RS4 injectors in some way so the spray angle is correct?

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[Gotpsi2008]

It won't do much. Maybe if your tune calls for it for some reason (e85) and you have an upgraded hpfp. But on k03 it shouldn't be needed

I have the upgraded HPFP but still stock injectors , 93 oct, k03, and its the 126 bar so just thinking of any potential weak points before FMIC

[p0isin]

RS4 injectors can be tuned to work just fine with our cars but most tuners aren't willing/able to make them work ideally so you'll see some black smoke sometimes.

Plenty of people on this forum have been fine with rs4 injectors if you can deal with some rough cold starts and occasional black smoke.

I think you need to look into injection time, angle, etc. maps for that.

- - - Updated - - -

I have the upgraded HPFP but still stock injectors , 93 oct, k03, and its the 126 bar so just thinking of any potential weak points before FMIC

Take data logs and see if your tune requests >125 bar

[StatusQuo]

I managed to run 100% e85 on stock injectors on a stage 2 K03 tune. The two issues I had was my LPFP was working it's ass off and I couldnt tune cold start. It was a total bish.



Not recommended. My LTFT was 13% and me duty cycle during the boost spike was too high for comfort

Sweet spot I found was a 25% mix. No issues then and started like stock.



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[StatusQuo]

RS4 injectors can be tuned to work just fine with our cars but most tuners aren't willing/able to make them work ideally so you'll see some black smoke sometimes.

Plenty of people on this forum have been fine with rs4 injectors if you can deal with some rough cold starts and occasional black smoke.

I think you need to look into injection time, angle, etc. maps for that.

- - - Updated - - -



Take data logs and see if your tune requests >125 bar

I think I might go RS4. I know the S3 is the correct angle but we know the RS4 flows more. I'm totally willing to deal with black smoke. My biggest concern is fueling.




Not possible to rotate them?

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[p0isin]

It's not just a matter of rotating them. They don't have as wide a spray so you get more concentrated spots of fuel in the cylinder vs. s3 injectors.

You'd have to adjust injection timing angle as well as injection pulse time, warmup fuel correction, acceleration fuel, and a few other maps if you wanted to fine tune the rs4 injectors.

[StatusQuo]

It's not just a matter of rotating them. They don't have as wide a spray so you get more concentrated spots of fuel in the cylinder vs. s3 injectors.

You'd have to adjust injection timing angle as well as injection pulse time, warmup fuel correction, acceleration fuel, and a few other maps if you wanted to fine tune the rs4 injectors.

Got it. I also messaged Eric and I asked him what injectors he's tried.

I got the ATP GTX2867R kit as well.


I was gonna start off by copying the injector maps off the maestro RS4 injector base files for the BPY. There is a "stage 3" file that uses RS4 injectors

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[Okedokey]

Got it. I also messaged Eric and I asked him what injectors he's tried.

I got the ATP GTX2867R kit as well.


I was gonna start off by copying the injector maps off the maestro RS4 injector base files for the BPY. There is a "stage 3" file that uses RS4 injectors

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Car to share that file?

[p0isin]

Got it. I also messaged Eric and I asked him what injectors he's tried.

I got the ATP GTX2867R kit as well.


I was gonna start off by copying the injector maps off the maestro RS4 injector base files for the BPY. There is a "stage 3" file that uses RS4 injectors

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Cool. I got my GTX setup from Pag Parts Turbo. My build thread is HERE.

The car is so much fun to drive. Turbo makes about 20 psi boost @ 3300 RPM in 2nd gear and 30 psi boost @ 3250 RPM in 3rd gear.

Here are some data log graphs that show boost curve on 93 octane.




For comparison here are max MAF readings from my different setups:

K03 = 196 g/s

F23L = 260 g/s

GTX2867r = 350 g/s

[Okedokey]

Wow, nice numbers!

[StatusQuo]

Cool. I got my GTX setup from Pag Parts Turbo. My build thread is HERE.

The car is so much fun to drive. Turbo makes about 20 psi boost @ 3300 RPM in 2nd gear and 30 psi boost @ 3250 RPM in 3rd gear.

Here are some data log graphs that show boost curve on 93 octane.




For comparison here are max MAF readings from my different setups:

K03 = 196 g/s

F23L = 260 g/s

GTX2867r = 350 g/s

Love it! Mind if I ask what program are you using for the graphs?

Yeah man. I'm about to start the install next week. I'm planning to go mafless run the most ricer bov I can find lol.

I picked up the kit actually off the forums used.

I've always been a sucker for early spool and the turbo fits the bill!

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[p0isin]

Cool, I'm no expert with Maestro but I can try to help if you run into any issues.

I just used Microsoft Excel 2010 to make the graphs.

[StatusQuo]

Cool, I'm no expert with Maestro but I can try to help if you run into any issues.

I just used Microsoft Excel 2010 to make the graphs.

Thanks dude! Yeah I'll let you know if I need any sorting out.

How much peak TQ would you feel safe running on a stock motor?

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[klrider44]

I forgot about this part. When rapidly cutting the throttle after a WOT run, my old car would always spike to the PRV set pressure in logs. Who knows how high it would go if there was a bolt there instead.

What is the explanation for this then



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[vce1232000]

What is the explanation for this then

They are speaking about the pressure relief valve on the side of the engine. Not the psi relief valve on the hpfp. They are different

[vce1232000]

RS4 injectors can be tuned to work just fine with our cars but most tuners aren't willing/able to make them work ideally so you'll see some black smoke sometimes.

Plenty of people on this forum have been fine with rs4 injectors if you can deal with some rough cold starts and occasional black smoke.

I'm totally willing to deal with black smoke. My biggest concern is fueling.

I have S3 injectors and under wot they blow black smoke from fuel enrichment. My exhaust tips are covered in black soot But no cold start issue's

[Okedokey]

Im sure this is a dumb question, but is there actually evidence that upgraded injectors are actually needed for a K04. I mean is there data showing this?

[StatusQuo]

^^ yupyup

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[Okedokey]

^^ yupyup

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Thanks mate, but where is it? Not being rude, just I trust that this is a known, but yet to see any proof and such (sorry its the engineer/scientist in me).

[StatusQuo]

Thanks mate, but where is it? Not being rude, just I trust that this is a known, but yet to see any proof and such (sorry its the engineer/scientist in me).

Woops. I ment that as the clarification to what vce stated. You and I posted at the same time

Sorry for the misunderstanding

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[aluthman]

Ericpaulyoung may have been playing around with those injectors. Better spray pattern if they are the ones I'm thinking of, just not sure on their flow rates.

He was running B8 RS4 injectors last I read. Same flow as the B7 RS4 injectors apparently, but with a multi nozzle tip that works better with our engines. You have to source them from overseas though, and wiring adapters are required.

Is there any point to upgrade the PRV if your still stock injectors?

If your tune requests a higher rail pressure than your current prv is rated for, then yes.

Im sure this is a dumb question, but is there actually evidence that upgraded injectors are actually needed for a K04. I mean is there data showing this?

It can be done, but you can't max it out and the injector duty cycle is tapped out. Your injectors won't last long under those conditions, especially if they are tired originals.

[StatusQuo]

But to answer your question, it's a mixed bag really. No one besides the manufacturer really knows the injector characteristics and flow rate of all these OEM injectors.


Literally the only way we know how much injector we have is pulswidth and if target lambda is being met (assuming the map/maf is calibrated properly)

Flow can be increased with pressure. This is actually what I'm going to try first. I'm going to run the stock injectors at 175bar and see how far I can push it.

You could run a K04 on stock injectors at 130bar. But if the injector cannot supply the volume of fuel required for a given volume of air, then you would have to run lower boost.


I ran full e85 on stock injectors on stage 2. That's 35% more fuel. Stage 2 is 260chp.

I might get some dirt for saying this, but I feel that stock injectors CAN support ~325 chp at 130bar tops and even that is pushing it. It would meet requested​ lambda. You would have to run 91. No ethanol.

I wanna see how much 175bar can push on 91.

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[p0isin]

Based on known injector constants the S3 injectors flow at least more than 15% vs. Stock injectors.

Injector Constant = KRKTE = Load to Injection Time Conversion Factor
Stock Injector Constant = .03332
S3 Injector Constant = .028770
RS4 Injector Constant = .02699

[aluthman]

Those are the commonly used injector constants, but I question their accuracy. I reduced my injector constant by 10% in Maestro on my S3 injectors to get my fuel trims in check, so I'm not sure you can get an accurate flow comparison through the commonly used injector constants.