Bigger injectors for GTI

[Pommie]

I have been searching for a while but with no luck so I thought I'd ask the question.

I have been having problems with my 08 Polo GTI pinging under heavy load (FOOT TO FLOOR). I have a K04 Turbo, 2.5" manifold back system, 4bar FPR and APR K04 tune.
I was thinking that under extreme thrashing the stock injectors can not flow enough fuel to supply the engine, therefore I may need bigger injectors.
My question is what size are the stock injectors? does anyone know of a good upgrade? how much and where could I get them? and lastly is it an easy job to do yourself?

Many thanks Pommie

[DeanB]

Have you thought about contacting APR and seeing what they recommend ? Would make sense to me.

Also it would be worth finding someone with vagcom to run a scan and see what's going on.

[seangti]

Or put it on a dyno to see what's going on. Measure injector duty cycle and AFR's and/or EGT to get a good understanding of what it's doing.

[kaanage]

It could also be that the fuel pump can't keep up with the demand from the injection cycles.
But I agree with DeanB - with that level of modification, you need to start looking at the logs to be certain what it going on.

[noone]

Log it. There are systems to reduce timing if the knock is too much, you should be able to see that in logging very easily.

Def call APR as well.

[Guy_H]

Injectors are plenty big enough for K04 - log as suggested above & make sure your fuel pump isn't on the way out.

[vwthunder]

I dont know why some of the other tunes require different injectors eg OEM TT ones.

Im guessing the tune is not as agressive as others which require more fuel.

On saying that I am thinking of a K04 and seeing as I have the APR K03 tune, it is the cheapest option.

Can you give us your thoughts on the K04, is it a genuine turbo, or something like a RP turbo ??

[Pommie]

Thanks for the replies, I'm now just waiting on APR to get back to the dealer. He said it may be worth re-flashing it as it seemed ok when it was first done, also to give it a scan and see what's going on. I'll let you know.
As for the difference with the KO4, it is like chork and cheese from the K03 that had the APR tune. It's now a bit mental even in second it lights up the wheels - I would not want any more power... It is not a genuine K04.

[vwthunder]

As for the difference with the KO4, it is like chork and cheese from the K03 that had the APR tune. It's now a bit mental even in second it lights up the wheels - I would not want any more power... It is not a genuine K04.

Wow that is great to know, do you have a boost gauge in there?

I am seriously thiking of doing it

[Pommie]

for me it was the same difference as when I first got the std car APR tuned. Sorry no boost gauge.
The best thing was, the turbo cost about $400 from the States.