ALH turbo upgrade question

wauwau

Member
Joined
Jun 9, 2021
Location
Germany
TDI
New Beetle 1.9TDI ALH
Not at all ! You just reduce the IQ in the software !
Reducing the IQ in the software, you mean the mapping or via VCDS or the hammer mod?

What would be the benefits of the bigger nozzles if i have to lower the fuelling, shouldn't i just use smaller nozzles?
 

adamss24

Veteran Member
Joined
Nov 2, 2005
Location
Great Britain
TDI
audi a4 2.5 tdi 98 quatrro 6speed
The benefit of larger nozzles is headroom and better atomization into a shorter window ! The power is addictive and you get used to it, best to have fueling sorted in the tune than having to go trough the swapping of injector nozzles all over again when you’re bored of the power !
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
Reducing the IQ in the software, you mean the mapping or via VCDS or the hammer mod?

What would be the benefits of the bigger nozzles if i have to lower the fuelling, shouldn't i just use smaller nozzles?
thats not how it works. you are moving the fuel map by shifting the cam on the QA. NOT changing how much fuel it gets, just when it gets it. kinda..... its complicated. Just know if you DO NOT raise the QA on bigger nozzles with out an EGT gauge and boost to back that fuel map up... you WILL have EGTs that can and will destroy the turbo in just a second.
 

wauwau

Member
Joined
Jun 9, 2021
Location
Germany
TDI
New Beetle 1.9TDI ALH
Ok, but shouldn't 0.230 nozzles be enough instead of the 0.216? But at first i have to take a look at my current tune an try to modify it myself.
 

wauwau

Member
Joined
Jun 9, 2021
Location
Germany
TDI
New Beetle 1.9TDI ALH
thats not how it works. you are moving the fuel map by shifting the cam on the QA. NOT changing how much fuel it gets, just when it gets it. kinda..... its complicated. Just know if you DO NOT raise the QA on bigger nozzles with out an EGT gauge and boost to back that fuel map up... you WILL have EGTs that can and will destroy the turbo in just a second.
If i understand correctly, if i take my current fuel maps and multiply them with 0.83 wouldn't i get nearly the same amount of fuel with 0.260 nozzles? Just trying to understand mappings. So, with bigger nozzles, would it be possible to alter the SOI and the Injection time, becuse more fuel is delivered in the same time?
 

PakProtector

Veteran Member
Joined
Jan 5, 2014
Location
AnnArbor, MI
TDI
Mk.4 and the Cummins-es
Hmmm...I like to look at the extremes; book-ending a question so to speak. I am fairly sure with a big enough pump/injector set up one could have a 'nominal' SOI, and deliver enough fuel fast enough to burn the edges of the bowl. Not sure where this lies on the spectrum, but I suspect it is near one end. The other end is pointless to look at as it involves long duration and small injectors...

I would think a slightly expanded pilot injection event, starting from something like factory acceptable specs would be useful...then dump in the rest quickly and from higher pressure. The 'the rest' happening whilst it is least likely to impinge on the bowl edges.

Douglas
 
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