My 20v 2.5 stroker track day ur quattro

[DamoM]

Any boost and rpm graphs. Interested in how responsive this turbo is.

Yes I have. I'll upload them...

[DamoM]

File names should be self-explanatory...

[ATTACH]41195[/ATTACH]

[ATTACH]41196[/ATTACH]

[ATTACH]41197[/ATTACH]

[jsws3]

Yeah it's a real blow. I think that the 1000cc injectors might already have been ordered! It won't be long!

I have ev14 750 do you think the gtx will out flow them and would need to go bigger ?

[DamoM]

I have ev14 750 do you think the gtx will out flow them and would need to go bigger ?

No I think they'll be fine. I think that we might have actually gone for these:

http://www.034motorsport.com/fuel-injection-solutions-fuel-injectors-850cc-bosch-ev14-fuel-injector-p-19844.html

There is a genuine lack of choice in the uk though?

[Audi_CQ]

Well had the car remapped. My 660cc injectors are running at 90% of their duty cycle and so this is holding it back and I can only run 1.6 bar boost. Exhaust is restrictive (a 20+ year old Scorpion!) and the inlet filter is too small (they'd sent the wrong one and it cost 25 bhp compared to the plot without it fitted).

Net result was 404bhp FWHP which was quite disappointing.

I will post the dyno plot when I get a chance.

Car went well though and the GTX3071 turbo seemed good if not fantastic.

So new injectors, better exhaust and revised inlet setup = MORE MONEY!!!

660 injectors at 90% at only 400hp? (3 bar fuel pressure? With 4bar fpr the injectors should deliver enough for that turbo)
Must be something else then injectors holding it back. Have you measured back pressure?

[jade]

660 injectors at 90% at only 400hp? (3 bar fuel pressure? With 4bar fpr the injectors should deliver enough for that turbo)
Must be something else then injectors holding it back. Have you measured back pressure?

Agree

I am running 550+ on 660cc at 4 bar

[prj]

Sounds like fuel pump is tapering badly.

660cc injectors at 90% will give over 550hp at the crank.

[DamoM]

660 injectors at 90% at only 400hp? (3 bar fuel pressure? With 4bar fpr the injectors should deliver enough for that turbo)
Must be something else then injectors holding it back. Have you measured back pressure?

We are at 3.8 bar fuel pressure and 90% duty cycle. How do you measure back pressure?

[DamoM]

Agree

I am running 550+ on 660cc at 4 bar

Have you got a dyno plot? Would be good to compare.

[DamoM]

Sounds like fuel pump is tapering badly.

660cc injectors at 90% will give over 550hp at the crank.

Guess that would make sense. How would you go about measuring if it was?

[DJones]

Guess that would make sense. How would you go about measuring if it was?

My measure has always been a little agricultural but it has worked for me.. I always want to see 2 to 2.5 litres on the return.

I apply the same amount of pressure to the FPR as the turbo would and apply 12v to the pump in the same way as the ECU would (i.e. earth it) hold it for 15 seconds and * it by four, so long as its 2+ litres in the return to the tank i'm happy...

I'm sure there is better ways but that's what i do...

[prj]

Guess that would make sense. How would you go about measuring if it was?

The only correct way to test the pressure is have a gauge attached while making a run at WOT. Testing at idle is useless... also the backpressure has no effect on this.

Before you spend ages testing, make sure your pump's pickup is clean, you are using an adequate fuel pump and the fuel pump is relayed separately to feed directly from the battery and there is no voltage drop.

Kinda surprised your tuner didn't pick that up, it's way out.
Furthermore, fitting bigger injectors will accomplish absolutely nothing, they won't flow more up top, because they are not the choke point.

[Audi_CQ]

We are at 3.8 bar fuel pressure and 90% duty cycle. How do you measure back pressure?

Do you have a fuel pressure gauge fitted? If not Mount one and watch it under load on the dyno. Should be 3.8 + boost (5,4bar if 1.6bar boost).

To measure backpressure you need to tap into the ex. manifold collector/turbo housing and connect it to a boost/pressure gauge then take a reading when on full power on the dyno.

[prj]

Do you have a fuel pressure gauge fitted? If not Mount one and watch it under load on the dyno. Should be 3.8 + boost (5,4bar if 1.6bar boost).

To measure backpressure you need to tap into the ex. manifold collector/turbo housing and connect it to a boost/pressure gauge then take a reading when on full power on the dyno.

I think something is lost in translation.
Backpressure refers to the pressure in the exhaust manifold or the exhaust.

What you are talking about is pressure in the fuel rail, same thing as I am

[URquattroGus]

Damo. NO! Please stop this thread, must be satisfied with what I've got! Stop putting ideas into my head...!

Another interesting development, hope you get it all sorted Interested to know how well it spools up, presumably you should be able to hit 500bhp at the crank when everything is sorted?